Science.gov

Sample records for nox emission reduction

  1. NOx Emission Reduction by Oscillating Combustion

    SciTech Connect

    2005-09-01

    This project focuses on a new technology that reduces NOx emissions while increasing furnace efficiency for both air- and oxygen-fired furnaces. Oscillating combustion is a retrofit technology that involves the forced oscillation of the fuel flow rate to a furnace. These oscillations create successive, fuel-rich and fuel-lean zones within the furnace.

  2. Nox Emission Reduction in Commercial Jets Through Water Injection

    NASA Technical Reports Server (NTRS)

    Balepin, Vladimir; Ossello, Chris; Snyder, Chris

    2002-01-01

    This paper discusses a method of the nitrogen oxides (NOx) emission reduction through the injection of water in commercial turbofan engines during the takeoff and climbout cycles. In addition to emission reduction, this method can significantly reduce turbine temperature during the most demanding operational modes (takeoff and climbout) and increase engine reliability and life.

  3. NOx Emission Reduction by Oscillating combustion

    SciTech Connect

    Institute of Gas Technology

    2004-01-30

    High-temperature, natural gas-fired furnaces, especially those fired with preheated air, produce large quantities of NO{sub x} per ton of material processed. Regulations on emissions from industrial furnaces are becoming increasingly more stringent. In addition, competition is forcing operators to make their furnaces more productive and/or efficient. Switching from preheated air to industrial oxygen can increase efficiency and reduce NO{sub x}, but oxygen is significantly more costly than air and may not be compatible with the material being heated. What was needed, and what was developed during this project, is a technology that reduces NO{sub x} emissions while increasing furnace efficiency for both air- and oxy-fired furnaces. Oscillating combustion is a retrofit technology that involves the forced oscillation of the fuel flow rate to a furnace. These oscillations create successive, fuel-rich and fuel-lean zones within the furnace. Heat transfer from the flame to the load increases due to the more luminous fuel-rich zones, a longer overall flame length, and the breakup of the thermal boundary layer. The increased heat transfer shortens heat up times, thereby increasing furnace productivity, and reduces the heat going up the stack, thereby increasing efficiency. The fuel-rich and fuel-lean zones also produce substantially less NO{sub x} than firing at a constant excess air level. The longer flames and higher heat transfer rate reduces overall peak flame temperature and thus reduces additional NO{sub x} formation from the eventual mixing of the zones and burnout of combustibles from the rich zones. This project involved the development of hardware to implement oscillating combustion on an industrial scale, the laboratory testing of oscillating combustion on various types of industrial burners, and the field testing of oscillating combustion on several types of industrial furnace. Before laboratory testing began, a market study was conducted, based on the

  4. NOx Emission Reduction by Oscillating Combustion

    SciTech Connect

    John C. Wagner

    2004-03-31

    High-temperature, natural gas-fired furnaces, especially those fired with preheated air, produce large quantities of NO{sub x} per ton of material processed. Regulations on emissions from industrial furnaces are becoming increasingly more stringent. In addition, competition is forcing operators to make their furnaces more productive and/or efficient. Switching from preheated air to industrial oxygen can increase efficiency and reduce NO{sub x}, but oxygen is significantly more costly than air and may not be compatible with the material being heated. What was needed, and what was developed during this project, is a technology that reduces NO{sub x} emissions while increasing furnace efficiency for both air- and oxy-fired furnaces. Oscillating combustion is a retrofit technology that involves the forced oscillation of the fuel flow rate to a furnace. These oscillations create successive, fuel-rich and fuel-lean zones within the furnace. Heat transfer from the flame to the load increases due to the more luminous fuel-rich zones, a longer overall flame length, and the breakup of the thermal boundary layer. The increased heat transfer shortens heat up times, thereby increasing furnace productivity, and reduces the heat going up the stack, thereby increasing efficiency. The fuel-rich and fuel-lean zones also produce substantially less NO{sub x} than firing at a constant excess air level. The longer flames and higher heat transfer rate reduces overall peak flame temperature and thus reduces additional NO{sub x} formation from the eventual mixing of the zones and burnout of combustibles from the rich zones. This project involved the development of hardware to implement oscillating combustion on an industrial scale, the laboratory testing of oscillating combustion on various types of industrial burners, and the field testing of oscillating combustion on several types of industrial furnace. Before laboratory testing began, a market study was conducted, based on the

  5. REDUCTION OF NOx EMISSION FROM COAL COMBUSTION THROUGH OXYGEN ENRICHMENT

    SciTech Connect

    Western Research Institute

    2006-07-01

    BOC Process Gas Solutions and Western Research Institute (WRI) conducted a pilot-scale test program to evaluate the impact of oxygen enrichment on the emissions characteristics of pulverized coal. The combustion test facility (CTF) at WRI was used to assess the viability of the technique and determine the quantities of oxygen required for NOx reduction from coal fired boiler. In addition to the experimental work, a series of Computational Fluid Dynamics (CFD) simulations were made of the CTF under comparable conditions. A series of oxygen enrichment test was performed using the CTF. In these tests, oxygen was injected into one of the following streams: (1) the primary air (PA), (2) the secondary air (SA), and (3) the combined primary and secondary air. Emission data were collected from all tests, and compared with the corresponding data from the baseline cases. A key test parameter was the burner stoichiometry ratio. A series of CFD simulation models were devised to mimic the initial experiments in which secondary air was enriched with oxygen. The results from these models were compared against the experimental data. Experimental evidence indicated that oxygen enrichment does appear to be able to reduce NOx levels from coal combustion, especially when operated at low over fire air (OFA) levels. The reductions observed however are significantly smaller than that reported by others (7-8% vs. 25-50%), questioning the economic viability of the technique. This technique may find favor with fuels that are difficult to burn or stabilize at high OFA and produce excessive LOI. While CFD simulation appears to predict NO amounts in the correct order of magnitude and the correct trend with staging, it is sensitive to thermal conditions and an accurate thermal prediction is essential. Furthermore, without development, Fluent's fuel-NO model cannot account for a solution sensitive fuel-N distribution between volatiles and char and thus cannot predict the trends seen in the

  6. SELECTIVE CATALYTIC REDUCTION OF DIESEL ENGINE NOX EMISSIONS USING ETHANOL AS A REDUCTANT

    SciTech Connect

    Kass, M; Thomas, J; Lewis, S; Storey, J; Domingo, N; Graves, R Panov, A

    2003-08-24

    NOx emissions from a heavy-duty diesel engine were reduced by more than 90% and 80% utilizing a full-scale ethanol-SCR system for space velocities of 21000/h and 57000/h respectively. These results were achieved for catalyst temperatures between 360 and 400 C and for C1:NOx ratios of 4-6. The SCR process appears to rapidly convert ethanol to acetaldehyde, which subsequently slipped past the catalyst at appreciable levels at a space velocity of 57000/h. Ammonia and N2O were produced during conversion; the concentrations of each were higher for the low space velocity condition. However, the concentration of N2O did not exceed 10 ppm. In contrast to other catalyst technologies, NOx reduction appeared to be enhanced by initial catalyst aging, with the presumed mechanism being sulfate accumulation within the catalyst. A concept for utilizing ethanol (distilled from an E-diesel fuel) as the SCR reductant was demonstrated.

  7. Continuous reduction of cyclic adsorbed and desorbed NO(x) in diesel emission using nonthermal plasma.

    PubMed

    Kuwahara, Takuya; Nakaguchi, Harunobu; Kuroki, Tomoyuki; Okubo, Masaaki

    2016-05-01

    Considering the recent stringent regulations governing diesel NO(x) emission, an aftertreatment system for the reduction of NO(x) in the exhaust gas has been proposed and studied. The proposed system is a hybrid method combining nonthermal plasma and NOx adsorbent. The system does not require precious metal catalysts or harmful chemicals such as urea and ammonia. In the present system, NO(x) in diesel emission is treated by adsorption and desorption by adsorbent as well as nonthermal plasma reduction. In addition, the remaining NO(x) in the adsorbent is desorbed again in the supplied air by residual heat. The desorbed NO(x) in air recirculates into the intake of the engine, and this process, i.e., exhaust gas components' recirculation (EGCR) achieves NO(x) reduction. Alternate utilization of two adsorption chambers in the system can achieve high-efficiency NO(x) removal continuously. An experiment with a stationary diesel engine for electric power generation demonstrates an energy efficiency of 154 g(NO2)/kWh for NO(x) removal and continuous NO(x) reduction of 70.3%. Considering the regulation against diesel emission in Japan, i.e., the new regulation to be imposed on vehicles of 3.5-7.5 ton since 2016, the present aftertreatment system fulfills the requirement with only 1.0% of engine power.

  8. Continuous reduction of cyclic adsorbed and desorbed NO(x) in diesel emission using nonthermal plasma.

    PubMed

    Kuwahara, Takuya; Nakaguchi, Harunobu; Kuroki, Tomoyuki; Okubo, Masaaki

    2016-05-01

    Considering the recent stringent regulations governing diesel NO(x) emission, an aftertreatment system for the reduction of NO(x) in the exhaust gas has been proposed and studied. The proposed system is a hybrid method combining nonthermal plasma and NOx adsorbent. The system does not require precious metal catalysts or harmful chemicals such as urea and ammonia. In the present system, NO(x) in diesel emission is treated by adsorption and desorption by adsorbent as well as nonthermal plasma reduction. In addition, the remaining NO(x) in the adsorbent is desorbed again in the supplied air by residual heat. The desorbed NO(x) in air recirculates into the intake of the engine, and this process, i.e., exhaust gas components' recirculation (EGCR) achieves NO(x) reduction. Alternate utilization of two adsorption chambers in the system can achieve high-efficiency NO(x) removal continuously. An experiment with a stationary diesel engine for electric power generation demonstrates an energy efficiency of 154 g(NO2)/kWh for NO(x) removal and continuous NO(x) reduction of 70.3%. Considering the regulation against diesel emission in Japan, i.e., the new regulation to be imposed on vehicles of 3.5-7.5 ton since 2016, the present aftertreatment system fulfills the requirement with only 1.0% of engine power. PMID:26844402

  9. Waste Coal Fines Reburn for NOx and Mercury Emission Reduction

    SciTech Connect

    Stephen Johnson; Chetan Chothani; Bernard Breen

    2008-04-30

    Injection of coal-water slurries (CWS) made with both waste coal and bituminous coal was tested for enhanced reduction of NO{sub x} and Hg emissions at the AES Beaver Valley plant near Monaca, PA. Under this project, Breen Energy Solutions (BES) conducted field experiments on the these emission reduction technologies by mixing coal fines and/or pulverized coal, urea and water to form slurry, then injecting the slurry in the upper furnace region of a coal-fired boiler. The main focus of this project was use of waste coal fines as the carbon source; however, testing was also conducted using pulverized coal in conjunction with or instead of waste coal fines for conversion efficiency and economic comparisons. The host site for this research and development project was Unit No.2 at AES Beaver Valley cogeneration station. Unit No.2 is a 35 MW Babcock & Wilcox (B&W) front-wall fired boiler that burns eastern bituminous coal. It has low NO{sub x} burners, overfire air ports and a urea-based selective non-catalytic reduction (SNCR) system for NO{sub x} control. The back-end clean-up system includes a rotating mechanical ash particulate removal and electrostatic precipitator (ESP) and wet flue gas desulfurization (FGD) scrubber. Coal slurry injection was expected to help reduce NOx emissions in two ways: (1) Via fuel-lean reburning when the slurry is injected above the combustion zone. (2) Via enhanced SNCR reduction when urea is incorporated into the slurry. The mercury control process under research uses carbon/water slurry injection to produce reactive carbon in-situ in the upper furnace, promoting the oxidation of elemental mercury in flue gas from coal-fired power boilers. By controlling the water content of the slurry below the stoichiometric requirement for complete gasification, water activated carbon (WAC) can be generated in-situ in the upper furnace. As little as 1-2% coal/water slurry (heat input basis) can be injected and generate sufficient WAC for mercury

  10. Simultaneous reduction of particulate matter and NO(x) emissions using 4-way catalyzed filtration systems.

    PubMed

    Swanson, Jacob J; Watts, Winthrop F; Newman, Robert A; Ziebarth, Robin R; Kittelson, David B

    2013-05-01

    The next generation of diesel emission control devices includes 4-way catalyzed filtration systems (4WCFS) consisting of both NOx and diesel particulate matter (DPM) control. A methodology was developed to simultaneously evaluate the NOx and DPM control performance of miniature 4WCFS made from acicular mullite, an advanced ceramic material (ACM), that were challenged with diesel exhaust. The impact of catalyst loading and substrate porosity on catalytic performance of the NOx trap was evaluated. Simultaneously with NOx measurements, the real-time solid particle filtration performance of catalyst-coated standard and high porosity filters was determined for steady-state and regenerative conditions. The use of high porosity ACM 4-way catalyzed filtration systems reduced NOx by 99% and solid and total particulate matter by 95% when averaged over 10 regeneration cycles. A "regeneration cycle" refers to an oxidizing ("lean") exhaust condition followed by a reducing ("rich") exhaust condition resulting in NOx storage and NOx reduction (i.e., trap "regeneration"), respectively. Standard porosity ACM 4-way catalyzed filtration systems reduced NOx by 60-75% and exhibited 99.9% filtration efficiency. The rich/lean cycling used to regenerate the filter had almost no impact on solid particle filtration efficiency but impacted NOx control. Cycling resulted in the formation of very low concentrations of semivolatile nucleation mode particles for some 4WCFS formulations. Overall, 4WCFS show promise for significantly reducing diesel emissions into the atmosphere in a single control device.

  11. NOx Emission Reduction and its Effects on Ozone during the 2008 Olympic Games

    SciTech Connect

    Yang, Qing; Wang, Yuhang; Zhao, Chun; Liu, Zhen; Gustafson, William I.; Shao, Min

    2011-07-15

    We applied a daily-assimilated inversion method to estimate NOx (NO+NO2) emissions for June-September 2007 and 2008 on the basis of the Aura Ozone Monitoring Instrument (OMI) observations of nitrogen dioxide (NO2) and model simulations using the Regional chEmistry and trAnsport Model (REAM). Over urban Beijing, rural Beijing, and the Huabei Plain, OMI column NO2 reductions are approximately 45%, 33%, and 14%, respectively, while the corresponding anthropogenic NOx emission reductions are only 28%, 24%, and 6%, during the full emission control period (July 20 – Sep 20, 2008). The emission reduction began in early July and was in full force by July 20, corresponding to the scheduled implementation of emission controls over Beijing. The emissions did not appear to recover after the emission control period. Meteorological change from summer 2007 to 2008 is the main factor contributing to the column NO2 decreases not accounted for by the emission reduction. Model simulations suggest that the effect of emission reduction on ozone concentrations over Beijing is relatively minor using a standard VOC emission inventory in China. With an adjustment of the model emissions to reflect in situ observations of VOCs in Beijing, the model simulation suggests a larger effect of the emission reduction.

  12. Reductions of NOx emissions from the Bowline Point generating station

    SciTech Connect

    O`Sullivan, R.C.; Conti, A.V.; Hersh, S.

    1996-12-31

    Improved combustion hardware, based upon the simultaneous optimization of oil atomizer and flame stabilizer technologies, has been retrofitted to oil and gas fired boilers to reduce NO{sub x} emissions, particulate matter emissions, and opacity, and to provide operational and performance benefits. This technology, known as REACH, can be applied to wall and tangential-fired boilers at a fraction of the cost of installing new burners. In combination with conventional NO{sub x} controls such as overfire air, flue gas recirculation, and low-NO{sub x} burners, REACH technology can provide an additional increment in NO{sub x} reduction; often valuable for meeting and maintaining regulatory compliance. This paper describes the results achieved when this technology was applied to the boilers at Orange and Rockland Utilities` Bowline Point Station to meet NYSDEC part 227 regulations for the emissions of nitrogen oxides (NO{sub x}). Bowline Point Unit 1 is a 600 MWe tangentially fired boiler with no installed NO{sub x} control systems. Bowline Point No. 2 is a 600 MW opposed-wall fired boiler with overfire air and windbox flue gas recirculation capability.

  13. Reconciling NOx emissions reductions and ozone trends in the U.S., 2002-2006

    NASA Astrophysics Data System (ADS)

    Zhou, Wei; Cohan, Daniel S.; Napelenok, Sergey L.

    2013-05-01

    Dynamic evaluation seeks to assess the ability of photochemical models to replicate changes in air quality as emissions and other conditions change. When a model fails to replicate an observed change, a key challenge is to discern whether the discrepancy is caused by errors in meteorological simulations, errors in emission magnitudes and changes, or inaccurate responses of simulated pollutant concentrations to emission changes. In this study, the Community Multiscale Air Quality (CMAQ) model is applied to simulate the ozone (O3) change after the NOx SIP Call and mobile emission controls substantially reduced nitrogen oxides (NOx) emissions in the eastern U.S. from 2002 to 2006. For both modeled and observed O3, changes in episode average daily maximal 8-h O3 were highly correlated (R2 = 0.89) with changes in the 95th percentile, although the magnitudes of reductions increased nonlinearly at high percentile O3 concentrations. Observed downward changes in mean NOx (-11.6 to -2.5 ppb) and 8-h O3 (-10.4 to -4.7 ppb) concentrations in metropolitan areas in the NOx SIP Call region were under-predicted by 31%-64% and 26%-66%, respectively. The under-predicted O3 improvements in the NOx SIP Call region could not be explained by adjusting for temperature biases in the meteorological input, or by considering uncertainties in the chemical reaction rate constants. However, the under-prediction in O3 improvements could be alleviated by 5%-31% by constraining NOx emissions in each year based on observed NOx concentrations. This demonstrates the crucial need to accurately characterize changes in precursor emissions when dynamically evaluating a model's ability to simulate O3 responses to those changes.

  14. INVESTIGATION OF SELECTIVE CATALYTIC REDUCTION IMPACT ON MERCURY SPECIATION UNDER SIMULATED NOX EMISSION CONTROL CONDITIONS

    EPA Science Inventory

    Selective catalytic reduction (SCR) technology is being increasingly applied for controlling emissions of nitrogen oxides (NOx) from coal-fired boilers. Some recent field and pilot studies suggest that the operation of SCR could affect the chemical form of mercury in the coal com...

  15. Emission reduction of NOx, PM, PM-carbon, and PAHs from a generator fuelled by biodieselhols.

    PubMed

    Tsai, Jen-Hsiung; Chen, Shui-Jen; Huang, Kuo-Lin; Lin, Wen-Yinn; Lee, Wen-Jhy; Chao, How-Ran; Lin, Chih-Chung; Hsieh, Lien-Te

    2014-06-15

    This investigation examines the particulate matter (PM), particulate carbon, polycyclic aromatic hydrocarbons (PAHs), and nitrogen oxides (NOx) emitted from a generator fueled by petroleum diesel blended with waste-edible-oil-biodiesel and water-containing acetone. Experimental results show that using biodieselhols with water-containing (or pure) acetone as the fuel of generator, in comparison to using petroleum diesel, significantly reduces PM emission; roughly, this reduction increased as percentage of water-containing acetone increased. When the percentages of waste-edible-oil-biodiesel were ≤ 5 vol%, adding pure or water-containing acetone (1-3 vol%) to biodieselhols generated emission reductions of NOx, PM, particle-bound organic carbon (OC), total-PAHs, and total-BaPeq. Consequently, using water-containing acetone biodieselhols as an alternative generator fuel is feasible and helps recycle and reuse waste solvents containing water-containing acetone.

  16. Selective catalytic reduction operation with heavy fuel oil: NOx, NH3, and particle emissions.

    PubMed

    Lehtoranta, Kati; Vesala, Hannu; Koponen, Päivi; Korhonen, Satu

    2015-04-01

    To meet stringent NOx emission limits, selective catalytic reduction (SCR) is increasingly utilized in ships, likely also in combination with low-priced higher sulfur level fuels. In this study, the performance of SCR was studied by utilizing NOx, NH3, and particle measurements. Urea decomposition was studied with ammonia and isocyanic acid measurements and was found to be more effective with heavy fuel oil (HFO) than with light fuel oil. This is suggested to be explained by the metals found in HFO contributing to metal oxide particles catalyzing the hydrolysis reaction prior to SCR. At the exhaust temperature of 340 °C NOx reduction was 85-90%, while at lower temperatures the efficiency decreased. By increasing the catalyst loading, the low temperature behavior of the SCR was enhanced. The drawback of this, however, was the tendency of particle emissions (sulfate) to increase at higher temperatures with higher loaded catalysts. The particle size distribution results showed high amounts of nanoparticles (in 25-30 nm size), the formation of which SCR either increased or decreased. The findings of this work provide a better understanding of the usage of SCR in combination with a higher sulfur level fuel and also of ship particle emissions, which are a growing concern.

  17. Satellite-observed US power plant NOx emission reductions and their impact on air quality - article no. L22812

    SciTech Connect

    Kim, S.W.; Heckel, A.; McKeen, S.A.; Frost, G.J.; Hsie, E.Y.; Trainer, M.K.; Richter, A.; Burrows, J.P.; Peckham, S.E.; Grell, G.A.

    2006-11-29

    Nitrogen oxide (NOx) emissions resulting from fossil fuel combustion lead to unhealthy levels of near-surface ozone (O{sub 3}). One of the largest U.S. sources, electric power generation, represented about 25% of the U.S. anthropogenic NOx emissions in 1999. Here we show that space-based instruments observed declining regional NOx levels between 1999 and 2005 in response to the recent implementation of pollution controls by utility companies in the eastern U.S. Satellite-retrieved summertime nitrogen dioxide (NO{sub 2}) columns and bottom-up emission estimates show larger decreases in the Ohio River Valley, where power plants dominate NOx emissions, than in the northeast U.S. urban corridor. Model simulations predict lower O{sub 3} across much of the eastern U.S. in response to these emission reductions.

  18. Reductions in particulate and NO(x) emissions by diesel engine parameter adjustments with HVO fuel.

    PubMed

    Happonen, Matti; Heikkilä, Juha; Murtonen, Timo; Lehto, Kalle; Sarjovaara, Teemu; Larmi, Martti; Keskinen, Jorma; Virtanen, Annele

    2012-06-01

    Hydrotreated vegetable oil (HVO) diesel fuel is a promising biofuel candidate that can complement or substitute traditional diesel fuel in engines. It has been already reported that by changing the fuel from conventional EN590 diesel to HVO decreases exhaust emissions. However, as the fuels have certain chemical and physical differences, it is clear that the full advantage of HVO cannot be realized unless the engine is optimized for the new fuel. In this article, we studied how much exhaust emissions can be reduced by adjusting engine parameters for HVO. The results indicate that, with all the studied loads (50%, 75%, and 100%), particulate mass and NO(x) can both be reduced over 25% by engine parameter adjustments. Further, the emission reduction was even higher when the target for adjusting engine parameters was to exclusively reduce either particulates or NO(x). In addition to particulate mass, different indicators of particulate emissions were also compared. These indicators included filter smoke number (FSN), total particle number, total particle surface area, and geometric mean diameter of the emitted particle size distribution. As a result of this comparison, a linear correlation between FSN and total particulate surface area at low FSN region was found.

  19. Reduction of NOx emissions on oil firing at Bowline Point Unit No. 2

    SciTech Connect

    Conti, A.V.; Lucente, J.; O`Sullivan, R.C.; Schmidt, D.W.

    1995-12-31

    Improved combustion technology, based upon optimization of oil atomizer and flame stabilizer design, has been retrofitted to oil and oil/gas fired boilers to reduce NOx emissions, particulate matter emissions, opacity, and to provide operational and performance benefits. This technology, known as REACH, can be applied to wall and tangential-fired boilers at a fraction of the cost of installing new burners. The technology is also compatible with conventional NOx controls such as overfire air, flue gas recirculation, low-NOx burners, and can be combined with these controls to further reduce NOx Emissions. This paper describes the results achieved when this technology was applied to Orange and Rockland Utilities` Bowline Point Unit No. 2 to meet NYSDEC part 227 regulations for the emissions of nitrogen oxides (0.25 lbs/MBtu). Bowline Point No. 2 is a 600 MW opposed-wall fired boiler with overfire air and flue gas recirculation capability.

  20. Design and testing of an independently controlled urea SCR retrofit system for the reduction of NOx emissions from marine diesels.

    PubMed

    Johnson, Derek R; Bedick, Clinton R; Clark, Nigel N; McKain, David L

    2009-05-15

    Diesel engine emissions for on-road, stationary and marine applications are regulated in the United States via standards set by the Environmental Protection Agency (EPA). A major component of diesel exhaust that is difficult to reduce is nitrogen oxides (NOx). Selective catalytic reduction (SCR) has been in use for many years for stationary applications, including external combustion boilers, and is promising for NOx abatement as a retrofit for mobile applications where diesel compression ignition engines are used. The research presented in this paper is the first phase of a program focused on the reduction of NOx by use of a stand-alone urea injection system, applicable to marine diesel engines typical of work boats (e.g., tugs). Most current urea SCR systems communicate with engine controls to predict NOx emissions based on signals such as torque and engine speed, however many marine engines in use still employ mechanical injection technology and lack electronic communication abilities. The system developed and discussed in this paper controls NOx emissions independentof engine operating parameters and measures NOx and exhaust flow using the following exhaust sensor inputs: absolute pressure, differential pressure, temperature, and NOx concentration. These sensor inputs were integrated into an independent controller and open loop architecture to estimate the necessary amount of urea needed, and the controller uses pulse width modulation (PWM) to power an automotive fuel injector for airless urea delivery. The system was tested in a transient test cell on a 350 hp engine certified at 4 g/bhp-hr of NOx, with a goal of reducing the engine out NOx levels by 50%. NOx reduction capabilities of 41-67% were shown on the non road transient cycle (NRTC) and ICOMIA E5 steady state cycles with system optimization during testing to minimize the dilute ammonia slip to cycle averages of 5-7 ppm. The goal of 50% reduction of NOx can be achieved dependent upon cycle. Further

  1. Estimates of ozone response to various combinations of NO(x) and VOC emission reductions in the eastern United States

    NASA Technical Reports Server (NTRS)

    Roselle, Shawn J.; Schere, Kenneth L.; Chu, Shao-Hang

    1994-01-01

    There is increasing recognition that controls on NO(x) emissions may be necessary, in addition to existing and future Volatile Organic Compounds (VOC) controls, for the abatement of ozone (O3) over portions of the United States. This study compares various combinations of anthropogenic NO(x) and VOC emission reductions through a series of model simulations. A total of 6 simulations were performed with the Regional Oxidant Model (ROM) for a 9-day period in July 1988. Each simulation reduced anthropogenic NO(x) and VOC emissions across-the-board by different amounts. Maximum O3 concentrations for the period were compared between the simulations. Comparison of the simulations suggests that: (1) NO(x) controls may be more effective than VOC controls in reducing peak O3 over most of the eastern United States; (2) VOC controls are most effective in urban areas having large sources of emissions; (3) NO(x) controls may increase O3 near large point sources; and (4) the benefit gained from increasing the amount of VOC controls may lessen as the amount of NO(x) control is increased. This paper has been reviewed in accordance with the U.S. Environmental Protection Agency's peer and administrative review policies and approved for presentation and publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.

  2. Eco-friendly selection of ship emissions reduction strategies with emphasis on SOx and NOx emissions

    NASA Astrophysics Data System (ADS)

    Seddiek, Ibrahim S.; Elgohary, Mohamed M.

    2014-09-01

    Increasing amounts of ships exhaust gases emitted worldwide forced the International Maritime Organization to issue some restricted maritime legislation for reducing the adverse environmental impacts arising from such emissions. Consequently, ships emission reduction became one of the technical and economical challenges that facing the ships, operators. The present paper addresses the different strategies that can be used to reduce those emissions, especially nitrogen oxides and sulfur oxides. The strategies included: applying reduction technologies onboard, using of alternative fuels, and follows one of fuel saving strategies. Using of selective catalytic reduction and sea water scrubbing appeared as the best reduction technologies onboard ships. Moreover, among the various proposed alternative fuels, natural gas, in its liquid state; has the priority to be used instead of conventional fuels. Applying one of those strategies is the matter of ship type and working area. As a numerical example, the proposed methods were investigated at a high-speed craft operating in the Red Sea area between Egypt and the Kingdom of Saudi Arabia. The results obtained are very satisfactory from the point of view of environment and economic issues, and reflected the importance of applying those strategies

  3. A new approach for estimation of the effect of NOx emission reduction on roadside NO2 concentration in Tokyo

    NASA Astrophysics Data System (ADS)

    Takekawa, Hideto; Chatani, Satoru; Ito, Akiyoshi

    2013-04-01

    The mean NO2/NOx ratios of vehicle emission, the mean duration time of NO reaction with O3 and background concentrations at the five most polluted roadside stations in Tokyo are estimated statistically using monitoring data at both roadside sites and urban background sites. These statistics are then used to categorize roadside NO2 into three components; NO2 emission from vehicles (primary NO2), oxidation of NO by O3 (secondary NO2) and background NO2 (BG NO2). Secondary NO2 and BG NO2 make a greater contribution to the high NO2 concentrations in spring and summer. On the other hand, BG NO2 contributes the dominant portion to high NO2 concentrations in winter. The effects of vehicle NOx emission reduction on the concentration of primary, secondary and BG NO2 are evaluated using an NO2 emission reduction scenario, an oxidation model proposed in this study and an air quality simulation, respectively. It is predicted that the shift to vehicles meeting the stringent emission regulation beginning in 2009 will lower the roadside NO2 concentration due mainly to the large decrease in secondary NO2. On the other hand, the reduction of NOx in vehicle emissions results in a smaller decrease in roadside NO2 in winter.

  4. Controlling NOx emission from industrial sources

    SciTech Connect

    Srivastava, R.K.; Nueffer, W.; Grano, D.; Khan, S.; Staudt, J.E.; Jozewicz, W.

    2005-07-01

    A number of regulatory actions focused on reducing NOx emissions from stationary combustion sources have been taken in the United States in the last decade. These actions include the Acid Rain NOx regulations, the Ozone Transport Commission's NOx Budget Program, and the NOx SIP Call rulemakings. In addition to these regulations, the recent Interstate Air Quality Rulemaking proposal and other bills in the Congress are focusing on additional reductions of NOx. Industrial combustion sources accounted for about 18016 of NOx emissions in the United States in 2000 and constituted the second largest emitting source category within stationary sources, only behind electric utility sources. Based on these data, reduction of NOx emissions from industrial combustion sources is an important consideration in efforts undertaken to address the environmental concerns associated with NOx. This paper discusses primary and secondary NOx control technologies applicable to various major categories of industrial sources. The sources considered in this paper include large boilers, furnaces and fired heaters, combustion turbines, large IC engines, and cement kilns. For each source category considered in this paper, primary NOx controls are discussed first, followed by a discussion of secondary NOx controls.

  5. Reduction on NOx emissions on urban areas by changing specific vehicle fleets: effects on NO2 and O3 concentration

    NASA Astrophysics Data System (ADS)

    Goncalves, M.; Jimenez, P.; Baldasano, J.

    2007-12-01

    The largest amount of NOx emissions in urban areas comes from on-road traffic, which is the largest contributor to urban air pollution (Colvile et al., 2001). Currently different strategies are being tested in order to reduce its effects; many of them oriented to the reduction of the unitary vehicles emissions, by alternative fuels use (such as biofuels, natural gas or hydrogen) or introduction of new technologies (such as hybrid electric vehicles or fuel cells). Atmospheric modelling permits to predict their consequences on tropospheric chemistry (Vautard et al., 2007). Hence, this work assesses the changes on NO2 and O3 concentrations when substituting a 10 per cent of the urban private cars fleets by petrol hybrid electric cars (HEC) or by natural gas cars (NGC) in Madrid and Barcelona urban areas (Spain). These two cities are selected in order to highlight the different patterns of pollutants transport (inland vs. coastal city) and the different responses to emissions reductions. The results focus on a typical summertime episode of air pollution, by means of the Eulerian air quality model ARW- WRF/HERMES/CMAQ, applied with high resolution (1-hr, 1km2) since of the complexity of both areas under study. The detailed emissions scenarios are implemented in the HERMES traffic emissions module, based on the Copert III-EEA/EMEP-CORINAIR (Nztiachristos and Samaras, 2000) methodology. The HEC introduction reduces NOx emissions from on-road traffic in a 10.8 per cent and 8.2 per cent; and the NGC introduction in a 10.3 per cent and 7.8 per cent, for Madrid and Barcelona areas, respectively. The scenarios also affect the NMVOCs reduction (ranging from -3.1 to -6.9 per cent), influencing the tropospheric photochemistry through the NOx/NMVOCs ratio. The abatement of the NO photooxidation but also to the reduction on primary NO2 involves a decrease on NO2 levels centred on urban areas. For example, the NO2 24-hr average concentration in downtown areas reduces up to 8 per

  6. Structure, Stability and Emissions of Lean Direct Injection Combustion, including a Novel Multi-Point LDI System for NOx Reduction

    NASA Astrophysics Data System (ADS)

    Villalva Gomez, Rodrigo

    Experimental research on Lean Direct Injection (LDI) combustors for gas turbine applications is presented. LDI combustion is an alternative to lean premixed combustion which has the potential of equivalent reduction of oxides of nitrogen (NOx) emissions and of peak combustor exit temperatures, but without some drawbacks of premixed combustors, such as flashback and autoignition. Simultaneous observations of the velocity field and reaction zone of an LDI swirl-stabilized combustor with a mixing tube at atmospheric conditions, with the goal of studying the flame stabilization mechanism, are shown. The flame was consistently anchored at the shear layer formed by the high-speed reactants exiting the mixing tube and the low speed recirculation region. Individual image analysis of the location of the tip of the recirculation zone and tip of the reaction region confirmed previously observed trends, but showed that calculation of the distance between these two points for corresponding image pairs yields results no different than when calculated from random image pairs. This most likely indicates a lag in the anchoring of the flame to changes in the recirculation zone, coupled with significant stochastic variation. An alternate LDI approach, multi-point LDI (MLDI), is also tested experimentally. A single large fuel nozzle is replaced by multiple small fuel nozzles to improve atomization and reduce the total volume of the high-temperature, low velocity recirculation zones, reducing NOx formation. The combustor researched employs a novel staged approach to allow good performance across a wide range of conditions by using a combination of nozzle types optimized to various power settings. The combustor has three independent fuel circuits referenced as pilot, intermediate, and outer. Emissions measurements, OH* chemiluminescence imaging, and thermoacoustic instability studies were run in a pressurized combustion facility at pressures from 2.0 to 5.3 bar. Combustor performance

  7. Impact of biogenic emissions on ozone and fine particles over Europe: Assessing the effect of temperature increase and the role of anthropogenic NOx emissions reduction

    NASA Astrophysics Data System (ADS)

    Tagaris, Efthimios; Sotiropoulou, Rafaella-Eleni P.; Gounaris, Nikos; Andronopoulos, Spyros; Vlachogiannis, Diamando

    2014-05-01

    The role of biogenic emissions on ozone and PM2.5 levels over Europe is assessed for July 2006 using the CMAQ modeling system. Biogenic emissions are simulated to increase the daily maximum 8 hour ozone (Max8hrO3) mixing ratios and to decrease PM2.5 average concentrations over Europe. Since climate change will lead to higher temperatures increasing subsequently biogenic emissions, sensitivity analysis to temperature is performed. Higher temperatures suggest an average increase in Max8hrO3 mixing ratios over Europe by about 3% and an average decrease in PM2.5 concentrations by about 6%, related to a temperature increase by 3 K degrees. Temperature increases are simulated, also, to increase the organic part of PM2.5 and to decrease the inorganic one on average over Europe. In order to examine if abatement measures for anthropogenic emissions could offset ozone increases in a warmer environment and their effect on PM2.5 concentrations, simulation with a domain wide reduction of anthropogenic NOx emissions by 10% is performed. This is estimated to reduce Max8hrO3 mixing ratios on average over Europe, however, in VOCs limited areas there is an increase. The reduction in anthropogenic NOx emissions is simulated to reduce PM2.5 concentrations on average over Europe enhancing the reduction simulated in a warmer environment but further modifying PM2.5 component concentrations. This work was supported by the National Strategic Reference Framework (NSRF) 2007-2013 grand No 09SYN-31-667.

  8. NOx emissions in China: historical trends and future perspectives

    NASA Astrophysics Data System (ADS)

    Zhao, B.; Wang, S. X.; Xu, J. Y.; Fu, K.; Klimont, Z.; Hao, J. M.; He, K. B.; Cofala, J.; Amann, M.

    2013-06-01

    Nitrogen oxides (NOx) are key pollutants for the improvement of ambient air quality. Within this study we estimated the historical NOx emissions in China for the period 1995-2010, and calculated future NOx emissions every five years until 2030 under six emission scenarios. Driven by the fast growth of energy consumption, we estimate the NOx emissions in China increased rapidly from 11.0 Mt in 1995 to 26.1 Mt in 2010. Power plants, industry and transportation were major sources of NOx emissions, accounting for 28.4, 34.0, and 25.4% of the total NOx emissions in 2010, respectively. Two energy scenarios, a business as usual scenario (BAU) and an alternative policy scenario (PC), were developed to project future energy consumption. In 2030, total energy consumption is projected to increase by 64 and 27% from 2010 level respectively. Three sets of end-of-pipe pollution control measures, including baseline, progressive, and stringent control case, were developed for each energy scenario, thereby constituting six emission scenarios. By 2030, the total NOx emissions are projected to increase (compared to 2010) by 36% in the baseline while policy cases result in reduction up to 61% in the most ambitious case with stringent control measures. More than a third of the reduction achieved by 2030 between least and most ambitious scenario comes from power sector and more than half is distributed equally between industry and transportation sectors. Selective Catalytic Reduction dominates the NOx emission reductions in power plants, while life style changes, control measures for industrial boilers and cement production are major contributors to reductions in industry. Timely enforcement of legislation on heavy duty vehicles would contribute significantly to NOx emission reductions. About 30% of the NOx emission reduction in 2020, and 40% of the NOx emission reduction in 2030 could be treated as the ancillary benefit of energy conservation. Sensitivity analysis was conducted to

  9. NOx emissions in China: historical trends and future perspectives

    NASA Astrophysics Data System (ADS)

    Zhao, B.; Wang, S. X.; Liu, H.; Xu, J. Y.; Fu, K.; Klimont, Z.; Hao, J. M.; He, K. B.; Cofala, J.; Amann, M.

    2013-10-01

    Nitrogen oxides (NOx) are key pollutants for the improvement of ambient air quality. Within this study we estimated the historical NOx emissions in China for the period 1995-2010, and calculated future NOx emissions every five years until 2030 under six emission scenarios. Driven by the fast growth of energy consumption, we estimate the NOx emissions in China increased rapidly from 11.0 Mt in 1995 to 26.1 Mt in 2010. Power plants, industry and transportation were major sources of NOx emissions, accounting for 28.4%, 34.0%, and 25.4% of the total NOx emissions in 2010, respectively. Two energy scenarios, a business as usual scenario (BAU) and an alternative policy scenario (PC), were developed to project future energy consumption. In 2030, total energy consumption is projected to increase by 64% and 27% from 2010 level respectively. Three sets of end-of-pipe pollution control measures, including baseline, progressive, and stringent control case, were developed for each energy scenario, thereby constituting six emission scenarios. By 2030, the total NOx emissions are projected to increase (compared to 2010) by 36% in the baseline while policy cases result in reduction up to 61% in the most ambitious case with stringent control measures. More than a third of the reduction achieved by 2030 between least and most ambitious scenario comes from power sector, and more than half is distributed equally between industry and transportation sectors. Selective catalytic reduction dominates the NOx emission reductions in power plants, while life style changes, control measures for industrial boilers and cement production are major contributors to reductions in industry. Timely enforcement of legislation on heavy-duty vehicles would contribute significantly to NOx emission reductions. About 30% of the NOx emission reduction in 2020 and 40% of the NOx emission reduction in 2030 could be treated as the ancillary benefit of energy conservation. Sensitivity analysis was conducted to

  10. Alternative control techniques document. NOx emissions from stationary gas turbines

    SciTech Connect

    Snyder, R.B.

    1993-01-01

    The Alternative Control Techniques document describes available control technologies for reducing NOx emissions levels from stationary combustion gas turbines. Information on the formation of NOx and uncontrolled NOx emissions from gas turbines is included. Water injection, steam injection, and low-NOx combustors, used independently or in combination with selective catalytic reduction (SCR), are discussed. Achievable controlled NOx emissions levels, costs and cost effectiveness, and environmental impacts are presented and applicability to new equipment as well as retrofit applications is discussed. The application of these technologies to gas turbines operating in offshore platform applications is included. Information on the use of alternate fuels, catalytic combustion, and selective noncatalytic reduction (SNCR) to reduce NOx emissions is also briefly presented.

  11. NOx reduction by electron beam-produced nitrogen atom injection

    DOEpatents

    Penetrante, Bernardino M.

    2002-01-01

    Deactivated atomic nitrogen generated by an electron beam from a gas stream containing more than 99% N.sub.2 is injected at low temperatures into an engine exhaust to reduce NOx emissions. High NOx reduction efficiency is achieved with compact electron beam devices without use of a catalyst.

  12. Selective catalytic reduction system and process for treating NOx emissions using a palladium and rhodium or ruthenium catalyst

    SciTech Connect

    Sobolevskiy, Anatoly; Rossin, Joseph A.; Knapke, Michael J.

    2011-07-12

    A process for the catalytic reduction of nitrogen oxides (NOx) in a gas stream (29) in the presence of H.sub.2 is provided. The process comprises contacting the gas stream with a catalyst system (38) comprising zirconia-silica washcoat particles (41), a pre-sulfated zirconia binder (44), and a catalyst combination (40) comprising palladium and at least one of rhodium, ruthenium, or a mixture of ruthenium and rhodium.

  13. Increased Use of Natural Gas for Power Generation in the U.S. and the Resulting Reductions in Emissions of CO2, NOx and SO2

    NASA Astrophysics Data System (ADS)

    De Gouw, J. A.; Parrish, D. D.; Trainer, M.

    2013-12-01

    Over the past decades, natural gas has increasingly replaced coal as a fuel for electrical power generation in the U.S. As a result, there have been significant reductions in the emissions of carbon dioxide (CO2), nitrogen oxides (NOx) and sulfur dioxide (SO2). Power plant emissions are continuously measured at the stack using continuous emissions monitoring systems (CEMS) required by the EPA. Previous studies using airborne measurements have shown these CEMS measurements to be accurate. Here, we use annual emissions since 1995 from all point sources included in the CEMS database to quantify the changes in CO2, NOx and SO2 emissions that have resulted from the changing use of fuels and technologies for power generation. In 1997, 83% of electrical power in the CEMS database was generated from coal-fired power plants. In 2012, the contribution from coal had decreased to 59%, and natural gas contributed 34% of the electrical power. Natural gas-fired power plants, in particular those equipped with combined cycle technology, emit less than 50% of CO2 per kWh produced compared to coal-fired plants. As a result of the increased use of natural gas, total CO2 emissions from U.S. power plants have decreased since 2008. In addition, natural gas-fired power plants emit less NOx and far less SO2 per kWh produced than coal-fired power plants. The increased use of natural gas has therefore led to significant emissions reductions of NOx and SO2 in addition to those obtained from the implementation of emissions control systems on coal-fired power plants. The increased use of natural gas for power generation has led to significant reductions in CO2 emissions as well as improvements in U.S. air quality. We will illustrate these points with examples from airborne measurements made using the NOAA WP-3D aircraft in the Southeastern U.S. in 2013 as part of the NOAA Southeast Nexus (SENEX) study. The emissions reductions from U.S. power plants due to the increased use of natural gas will

  14. Aircraft NO/x/ emissions and stratospheric ozone reductions - Another look

    NASA Technical Reports Server (NTRS)

    Turco, R. P.; Whitten, R. C.; Toon, O. B.; Inn, E. C. Y.; Hamill, P.

    1981-01-01

    New estimates for stratospheric ozone perturbations attributable to supersonic transport (SST) emissions are presented. First, a review is given of recent data pointing to lower OH concentrations below 30 km, as compared to the values predicted by photochemical models. The evidence for lower OH comes from a wide range of laboratory and atmospheric studies. The sensitivity of theoretical estimates of ozone change to OH abundances, and the coupling mechanisms between the O(x)-NO(x)-HO(x)-Cl(x) families which are responsible for the sensitivity, are discussed. Updated calculations for SST-induced ozone alterations are compared with older predictions. For example, assuming continuous aircraft injection of NO2 at 20 km at a rate of 1 x 10 to the 9th kg per year (globally), a 4% ozone decrease, is now calculated where earlier a 3% ozone increase was found. This large variance from previous forecasts suggests that new assessments of certain other polluting agents, particularly nitrogen fertilizers, are needed.

  15. Reducing NO(x) emissions from a nitric acid plant of domestic petrochemical complex: enhanced conversion in conventional radial-flow reactor of selective catalytic reduction process.

    PubMed

    Abbasfard, Hamed; Hashemi, Seyed Hamid; Rahimpour, Mohammad Reza; Jokar, Seyyed Mohammad; Ghader, Sattar

    2013-01-01

    The nitric acid plant of a domestic petrochemical complex is designed to annually produce 56,400 metric tons (based on 100% nitric acid). In the present work, radial-flow spherical bed reactor (RFSBR) for selective catalytic reduction of nitric oxides (NO(x)) from the stack of this plant was modelled and compared with the conventional radial-flow reactor (CRFR). Moreover, the proficiency of a radial-flow (water or nitrogen) membrane reactor was also compared with the CRFR which was found to be inefficient at identical process conditions. In the RFSBR, the space between the two concentric spheres is filled by a catalyst. A mathematical model, including conservation of mass has been developed to investigate the performance of the configurations. The model was checked against the CRFR in a nitric acid plant located at the domestic petrochemical complex. A good agreement was observed between the modelling results and the plant data. The effects of some important parameters such as pressure and temperature on NO(x) conversion were analysed. Results show 14% decrease in NO(x) emission annually in RFSBR compared with the CRFR, which is beneficial for the prevention of NO(x) emission, global warming and acid rain.

  16. Reducing NO(x) emissions from a nitric acid plant of domestic petrochemical complex: enhanced conversion in conventional radial-flow reactor of selective catalytic reduction process.

    PubMed

    Abbasfard, Hamed; Hashemi, Seyed Hamid; Rahimpour, Mohammad Reza; Jokar, Seyyed Mohammad; Ghader, Sattar

    2013-01-01

    The nitric acid plant of a domestic petrochemical complex is designed to annually produce 56,400 metric tons (based on 100% nitric acid). In the present work, radial-flow spherical bed reactor (RFSBR) for selective catalytic reduction of nitric oxides (NO(x)) from the stack of this plant was modelled and compared with the conventional radial-flow reactor (CRFR). Moreover, the proficiency of a radial-flow (water or nitrogen) membrane reactor was also compared with the CRFR which was found to be inefficient at identical process conditions. In the RFSBR, the space between the two concentric spheres is filled by a catalyst. A mathematical model, including conservation of mass has been developed to investigate the performance of the configurations. The model was checked against the CRFR in a nitric acid plant located at the domestic petrochemical complex. A good agreement was observed between the modelling results and the plant data. The effects of some important parameters such as pressure and temperature on NO(x) conversion were analysed. Results show 14% decrease in NO(x) emission annually in RFSBR compared with the CRFR, which is beneficial for the prevention of NO(x) emission, global warming and acid rain. PMID:24527652

  17. Effect of reductive treatments on Pt behavior and NOx storage in lean NOx trap catalysts

    SciTech Connect

    Wang, Xianqin; Kim, Do Heui; Kwak, Ja Hun; Wang, Chong M.; Szanyi, Janos; Peden, Charles HF

    2011-10-01

    Lean NOx trap (LNT) catalysts represent a promising approach to meet increasingly stringent NOx emission regulations on diesel and other lean-burn engines. Pt material properties, including dispersion and particle size, are known to be important factors in determining NOx uptake performance, since Pt provides active sites for NO oxidation to NO2 necessary for storing NOx as nitrates, and for the reduction of nitrates to N2. In this work, the physicochemical properties of Pt in Pt-BaO/Al2O3 LNT catalysts, such as the Pt accessible surface area and particle size, were investigated by using various tools, such as irreversible volumetric H2 chemisorption, high resolution transmission electron microscopy (HRTEM), and X-ray diffraction (XRD), following successive reductive treatments at elevated temperatures. NOx uptake activities were also measured to establish a relationship between the properties of Pt and NOx storage following identical high-temperature reductive treatments. We find that the reductive treatments of Pt-BaO/Al2O3 lean NOx trap catalysts at temperatures up to 500 ºC promote a significant increase in NOx uptake explained, in part, by an induced close interaction between Pt and BaO phases in the catalyst, thus enabling facilitation of the NOx storage process.

  18. Catalytic effects of minerals on NOx emission from coal combustion

    SciTech Connect

    Yao, M.Y.; Che, D.F.

    2007-07-01

    The catalytic effects of inherent mineral matters on NOx emissions from coal combustion have been investigated by a thermo-gravimetric analyzer (TGA) equipped with a gas analyzer. The effect of demineralization and the individual effect of Na, K, Ca, Mg, and Fe on the formation of NOx are studied as well as the combined catalytic effects of Ca + Na and Ca + Ti. Demineralization causes more Fuel-N to retain in the char, and reduction of NOx mostly. But the mechanistic effect on NOx formation varies from coal to coal. Ca and Mg promote NOx emission. Na, K, Fe suppress NOx formation to different extents. The effect of transition element Fe is the most obvious. The combination of Ca + Na and Ca + Ti can realize the simultaneous control of sulfur dioxide and nitrogen oxides emissions.

  19. NOx Emission Reduction by the Optimization of the Primary Air Distribution in the 235Mwe CFB Boiler

    NASA Astrophysics Data System (ADS)

    Mirek, P.; Czakiert, T.; Nowak, W.

    The article presents the results of experimental studies conducted on a large-scale 235 MWe CFB (Circulating Fluidized Bed) boiler, in which the primary air distribution system was modified. The modification was connected with the change of internal geometry of primary air channels as well as internal space of plenum chamber. The obtained results have shown, that the optimization of primary air flow has a great influence on the intensity of the combustion process and the temperature distribution along the height of combustion chamber. As a result, the NOx emission has been reduced by up to ten percent and the temperature profile in the combustion chamber has been revealed to be more uniform.

  20. UREA INFRASTRUCTURE FOR UREA SCR NOX REDUCTION

    SciTech Connect

    Bunting, Bruce G.

    2000-08-20

    Urea SCR is currently the only proven NOX aftertreatment for diesel engines - high NOX reduction possible - some SCR catalyst systems are robust against fuel sulfur - durability has been demonstrated - many systems in the field - long history in other markets - Major limitations to acceptance - distribution of urea solution to end user - ensuring that urea solution is added to vehicle.

  1. Impact of NO(x) emissions reduction policy on hospitalizations for respiratory disease in New York State.

    PubMed

    Lin, Shao; Jones, Rena; Pantea, Cristian; Özkaynak, Halûk; Rao, S Trivikrama; Hwang, Syni-An; Garcia, Valerie C

    2013-01-01

    To date, only a limited number of studies have examined the impact of ambient pollutant policy on respiratory morbidities. This accountability study examined the effect of a regional pollution control policy, namely, the US Environmental Protection Agency's (EPA) nitrogen oxides (NO(x)) Budget Trading Program (NBP), on respiratory health in New York State (NYS). Time-series analysis using generalized additive models was applied to assess changes in daily hospitalizations for respiratory diseases in NYS after the implementation of the NBP policy. Respiratory end points in the summers during the baseline period (1997-2000) were compared with those during the post-intervention period (2004-2006). Stratified analyses were also conducted to examine whether health impacts of the NBP differed by socio-demographic, regional, or clinical characteristics. Following the implementation of EPA's NBP policy, there were significant reductions in mean ozone levels (-2% to -9%) throughout NYS. After adjusting for time-varying variables, PM(2.5) concentration, and meteorological factors, significant post-intervention declines in respiratory admissions were observed in the Central (-10.18, 95% confidence interval (CI): -14.18, -6.01), Lower Hudson (-11.05, 95% CI: -16.54, -5.19), and New York City Metro regions (-5.71, 95% CI: -7.39, -4.00), consistent with wind trajectory patterns. Stratified analyses suggest that admissions for asthma, chronic airway obstruction, among those 5-17 years old, self-payers, Medicaid-covered, and rural residents declined the most post-NBP. This study suggests that the NO(x) control policy may have had a positive impact on both air pollution levels statewide and respiratory health in some NYS regions. However, the effect varied by disease subgroups, region, and socio-demographic characteristics. PMID:22829050

  2. 40 CFR 76.6 - NOX emission limitations for Group 2 boilers.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... PROGRAMS (CONTINUED) ACID RAIN NITROGEN OXIDES EMISSION REDUCTION PROGRAM § 76.6 NOX emission limitations..., the date on which the unit is required to meet Acid Rain emission reduction requirements for SO2,...

  3. 40 CFR 76.6 - NOX emission limitations for Group 2 boilers.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... PROGRAMS (CONTINUED) ACID RAIN NITROGEN OXIDES EMISSION REDUCTION PROGRAM § 76.6 NOX emission limitations..., the date on which the unit is required to meet Acid Rain emission reduction requirements for SO2,...

  4. 40 CFR 76.6 - NOX emission limitations for Group 2 boilers.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... PROGRAMS (CONTINUED) ACID RAIN NITROGEN OXIDES EMISSION REDUCTION PROGRAM § 76.6 NOX emission limitations..., the date on which the unit is required to meet Acid Rain emission reduction requirements for SO2,...

  5. 40 CFR 76.6 - NOX emission limitations for Group 2 boilers.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... PROGRAMS (CONTINUED) ACID RAIN NITROGEN OXIDES EMISSION REDUCTION PROGRAM § 76.6 NOX emission limitations..., the date on which the unit is required to meet Acid Rain emission reduction requirements for SO2,...

  6. 40 CFR 76.6 - NOX emission limitations for Group 2 boilers.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... PROGRAMS (CONTINUED) ACID RAIN NITROGEN OXIDES EMISSION REDUCTION PROGRAM § 76.6 NOX emission limitations..., the date on which the unit is required to meet Acid Rain emission reduction requirements for SO2,...

  7. Emissions reductions strategies

    SciTech Connect

    Sirois, R.H.

    1996-12-31

    This paper consists of the series of viewgraphs used by the author during his presentation. They tabulate nitrogen oxide reduction techniques, technical evaluation of NOx control techniques, critical system design parameters for SNCR processes, major concerns for SCR retrofit applications, integrating technologies, sulfur dioxide control for a coal fired power plant, heavy metals on US EPA`s HAPs list, and mercury emissions. Other slides show flow charts of some of these processes, as well as diagrams of equipment.

  8. Final technical report on investigation of selective non-catalytic processes for in-situ reduction of NOx and CO emissions from marine gas turbines and diesel engines. Final technical report, 1 April 1994-31 March 1997

    SciTech Connect

    Bowman, C.T.; Hanson, R.K.

    1997-05-15

    The effectiveness of selective non-catalytic (SNCR) gas-phase reaction processes for NO(x) removal from combustion products at elevated pressures was investigated in a combined experimental and modeling research program. Calculations using existing chemical models for SNCR indicate that the temperature window for NO(x) removal by SNCR widens as pressure increases, resulting in NO(x) removal at higher temperatures than at ambient pressure. The calculations also show a significant reduction in the reaction time scale with increasing pressure. These observations suggest the possibility of utilizing SNCR for reducing NO(x) emissions from marine gas turbines and Diesel engines by direct injection of a reductant species into the combustion chamber, possibly as a fuel additive. Initial experiments were carried out at atmospheric pressure to allow comparison with previous measurements in order to verify the experimental approach. Following these validation tests, experiments were conducted at elevated pressures. Results from these tests, confirm the model predictions that the SNCR window for NO(x) removal widens as the pressure increases. In addition, a project was initiated, to develop compact, robust, solid-state microsensors for pollutant species for use in control systems for reduction of pollutant emissions. The sensor concept is based on integrated circuit fabrication technology that allows the integration of a metal-oxide sensor with associated electronic circuitry on a single chip. Initial efforts focused on development of a sensor for NO(x).

  9. Correlating Engine NOx Emission with Biodiesel Composition

    NASA Astrophysics Data System (ADS)

    Jeyaseelan, Thangaraja; Mehta, Pramod Shankar

    2016-06-01

    Biodiesel composition comprising of saturated and unsaturated fatty acid methyl esters has a significant influence on its properties and hence the engine performance and emission characteristics. This paper proposes a comprehensive approach for composition-property-NOx emission analysis for biodiesel fuels and highlights the pathways responsible for such a relationship. Finally, a procedure and a predictor equation are developed for the assessment of biodiesel NOx emission from its composition details.

  10. LOW-CONCENTRATION NOX EMISSIONS MEASUREMENT

    EPA Science Inventory

    The paper gives results of a recent series of low-concentration nitrogen oxides (NOx) emission measurements, made by Midwest Research Institute (MRI) during U.S. EPA-sponsored Environmental Technology Verification (ETV) test of a NOx control system called Xonon (TM) Cool Combust...

  11. Optimization of NOx emissions in Yangtze Delta Region using in-situ observations

    NASA Astrophysics Data System (ADS)

    Wang, Hengmao; Jiang, Fei; Jiang, Ziqiang; Liu, Jane; Chen, Jing Ming; Ju, Weimin

    2016-04-01

    Well quantified NOx emissions are essential for air quality forecasting and air pollution mitigation. The traditional "bottom-up" estimates of NOx emissions, using activity data and emission factors, are subject to large uncertainties, especially in China. Inverse modelling, often referred to as "top-down" approach, using atmospheric observations made from satellites and ground stations, provides an effective means to optimize bottom-up NOx emission inventory. The rapid expansion of air quality monitoring network in China offers an opportunity to constrain NOx emissions using in-situ ground measurements. We explore the potential of using NO2 observations from the air quality monitoring network to improve NOx emissions estimates in China. The four dimensional variational data assimilation (4DVAR) scheme in the Community Multi-scale Air Quality (CMAQ) adjoint model is implemented to infer NOx emissions in Yangtze Delta Region at 12 km resolution. The optimized NOx emissions are presented. The uncertainly reduction of estimates is analyzed and discussed.

  12. Characteristics of NOx emission from Chinese coal-fired power plants equipped with new technologies

    NASA Astrophysics Data System (ADS)

    Ma, Zizhen; Deng, Jianguo; Li, Zhen; Li, Qing; Zhao, Ping; Wang, Liguo; Sun, Yezhu; Zheng, Hongxian; Pan, Li; Zhao, Shun; Jiang, Jingkun; Wang, Shuxiao; Duan, Lei

    2016-04-01

    Coal combustion in coal-fired power plants is one of the important anthropogenic NOx sources, especially in China. Many policies and methods aiming at reducing pollutants, such as increasing installed capacity and installing air pollution control devices (APCDs), especially selective catalytic reduction (SCR) units, could alter NOx emission characteristics (NOx concentration, NO2/NOx ratio, and NOx emission factor). This study reported the NOx characteristics of eight new coal-fired power-generating units with different boiler patterns, installed capacities, operating loads, and coal types. The results showed that larger units produced less NOx, and anthracite combustion generated more NOx than bitumite and lignite combustion. During formation, the NOx emission factors varied from 1.81 to 6.14 g/kg, much lower than those of older units at similar scales. This implies that NOx emissions of current and future units could be overestimated if they are based on outdated emission factors. In addition, APCDs, especially SCR, greatly decreased NOx emissions, but increased NO2/NOx ratios. Regardless, the NO2/NOx ratios were lower than 5%, in accordance with the guidelines and supporting the current method for calculating NOx emissions from coal-fired power plants that ignore NO2.

  13. NASA Glenn High Pressure Low NOx Emissions Research

    NASA Technical Reports Server (NTRS)

    Tacina, Kathleen M.; Wey, Changlie

    2008-01-01

    In collaboration with U.S. aircraft engine companies, NASA Glenn Research Center has contributed to the advancement of low emissions combustion systems. For the High Speed Research Program (HSR), a 90% reduction in nitrogen oxides (NOx) emissions (relative to the then-current state of the art) has been demonstrated in sector rig testing at General Electric Aircraft Engines (GEAE). For the Advanced Subsonic Technology Program (AST), a 50% reduction in NOx emissions relative to the 1996 International Civil Aviation Organization (ICAO) standards has been demonstrated in sector rigs at both GEAE and Pratt & Whitney (P&W). During the Ultra Efficient Engine Technology Program (UEET), a 70% reduction in NOx emissions, relative to the 1996 ICAO standards, was achieved in sector rig testing at Glenn in the world class Advanced Subsonic Combustion Rig (ASCR) and at contractor facilities. Low NOx combustor development continues under the Fundamental Aeronautics Program. To achieve these reductions, experimental and analytical research has been conducted to advance the understanding of emissions formation in combustion processes. Lean direct injection (LDI) concept development uses advanced laser-based non-intrusive diagnostics and analytical work to complement the emissions measurements and to provide guidance for concept improvement. This paper describes emissions results from flametube tests of a 9-injection-point LDI fuel/air mixer tested at inlet pressures up to 5500 kPa. Sample results from CFD and laser diagnostics are also discussed.

  14. Modelling NOx emissions of single droplet combustion

    NASA Astrophysics Data System (ADS)

    Moesl, Klaus G.; Schwing, Joachim E.; Sattelmayer, Thomas

    2012-02-01

    An approach for modelling and simulation of the generation of nitrogen oxide (NOx) in the gas phase surrounding single burning droplets is presented. Assuming spherical symmetry (no gravity, no forced convection), the governing equations are derived first. Then simplifications are introduced and it is proven that they are appropriate. The influences of the initial droplet diameter, the ambient conditions, and the droplet pre-vapourisation on NOx are investigated. The fuel of choice is n-decane (C10H22) as it resembles kerosene and diesel fuel best, and the complexity of the reaction mechanism is manageable. Combinations of C10H22 mechanisms and well-established NOx kinetics are evaluated in detail and validated for their applicability in the context of this work. The conducted simulations of droplet combustion in an atmosphere of hot exhaust gas show that NOx formation (by mass of fuel) increases linearly with the droplet diameter. There is a trade-off between available oxygen and ambient temperature. Increasing the equivalence ratio of the exhaust gas leads to higher NOx emissions in the very lean regime, but to lower emissions if the equivalence ratio exceeds 0.85. Pre-vapourisation of fuel at ambient conditions becomes beneficial with respect to NOx emissions only if the degree of vapourisation is above a minimum limit. If less fuel is vapourised before ignition, the NOx emissions remain almost unaffected.

  15. Innovative clean coal technology: 500 MW demonstration of advanced wall-fired combustion techniques for the reduction of nitrogen oxide (NOx) emissions from coal-fired boilers. Final report, Phases 1 - 3B

    SciTech Connect

    1998-01-01

    This report presents the results of a U.S. Department of Energy (DOE) Innovative Clean Coal Technology (ICCT) project demonstrating advanced wall-fired combustion techniques for the reduction of nitrogen oxide (NOx) emissions from coal-fired boilers. The project was conducted at Georgia Power Company`s Plant Hammond Unit 4 located near Rome, Georgia. The technologies demonstrated at this site include Foster Wheeler Energy Corporation`s advanced overfire air system and Controlled Flow/Split Flame low NOx burner. The primary objective of the demonstration at Hammond Unit 4 was to determine the long-term effects of commercially available wall-fired low NOx combustion technologies on NOx emissions and boiler performance. Short-term tests of each technology were also performed to provide engineering information about emissions and performance trends. A target of achieving fifty percent NOx reduction using combustion modifications was established for the project. Short-term and long-term baseline testing was conducted in an {open_quotes}as-found{close_quotes} condition from November 1989 through March 1990. Following retrofit of the AOFA system during a four-week outage in spring 1990, the AOFA configuration was tested from August 1990 through March 1991. The FWEC CF/SF low NOx burners were then installed during a seven-week outage starting on March 8, 1991 and continuing to May 5, 1991. Following optimization of the LNBs and ancillary combustion equipment by FWEC personnel, LNB testing commenced during July 1991 and continued until January 1992. Testing in the LNB+AOFA configuration was completed during August 1993. This report provides documentation on the design criteria used in the performance of this project as it pertains to the scope involved with the low NOx burners and advanced overfire systems.

  16. NOx Reduction with Natural Gas for Lean Large-Bore Engine Applications Using Lean NOx Trap Aftertreatment

    SciTech Connect

    Parks, JE

    2005-02-11

    Large-bore natural gas engines are used for distributed energy and gas compression since natural gas fuel offers a convenient and reliable fuel source via the natural gas pipeline and distribution infrastructure. Lean engines enable better fuel efficiency and lower operating costs; however, NOx emissions from lean engines are difficult to control. Technologies that reduce NOx in lean exhaust are desired to enable broader use of efficient lean engines. Lean NOx trap catalysts have demonstrated greater than 90% NOx reduction in lean exhaust from engines operating with gasoline, diesel, and natural gas fuels. In addition to the clean nature of the technology, lean NOx traps reduce NOx with the fuel source of the engine thereby eliminating the requirement for storage and handling of secondary fuels or reducing agents. A study of lean NOx trap catalysts for lean natural gas engines is presented here. Testing was performed on a Cummins C8.3G (CG-280) engine on a motor dynamometer. Lean NOx trap catalysts were tested for NOx reduction performance under various engine operating conditions, and the utilization of natural gas as the reductant fuel source was characterized. Engine test results show that temperature greatly affects the catalytic processes involved, specifically methane oxidation and NOx storage on the lean NOx trap. Additional studies on a bench flow reactor demonstrate the effect of precious metal loading (a primary cost factor) on lean NOx trap performance at different temperatures. Results and issues related to the potential of the lean NOx trap technology for large-bore engine applications will be discussed.

  17. 40 CFR 75.19 - Optional SO2, NOX, and CO2 emissions calculation for low mass emissions (LME) units.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... for units equipped with SCR or SNCR), or, consistent with paragraph (c)(1)(iv)(C)(4) of this section, for a unit that uses SCR or SNCR to control NOX emissions, an estimated default NOX emission rate of 0... units that use selective catalytic reduction (SCR) or selective non-catalytic reduction (SNCR)...

  18. Development of Low-NOx Emission DME (Dimethyl Ether) Combustor

    NASA Astrophysics Data System (ADS)

    Matsumoto, Ryosuke; Ishihara, Isao; Ozawa, Mamoru; Imahori, Keizo

    This study focuses on fundamental characteristics of DME (Dimethyl Ether) combustion, aiming at the development of low-NOx combustion. DME is one of the most promising new alternative fuels owing to its cleanness of the exhaust gas and wide applications. Combustion experiments using a diffusion burner were conducted for characterizing DME through the comparison with the results of LPG and 13A-city gas. Experimental results demonstrated a high potential of DME for a boiler and a gas-turbine fuel. DME has a wide stable-combustion range compared with those of the other fuels. In this study, the concept of the low-NOx combustion, referred to as the tube-nested combustion, was applied to the DME combustion. This tube-nested combustor consists of tube banks to cool the burning flame leading to NOx reduction. Then, the NOx emission of the DME combustion was successfully reduced to a level suitable for practical applications.

  19. 40 CFR 76.5 - NOX emission limitations for Group 1 boilers.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... PROGRAMS (CONTINUED) ACID RAIN NITROGEN OXIDES EMISSION REDUCTION PROGRAM § 76.5 NOX emission limitations..., the date on which the unit is required to meet Acid Rain emission reduction requirements for SO2, the... 404(d) of the Act, the date the unit is required to meet Acid Rain emissions reduction...

  20. 40 CFR 76.5 - NOX emission limitations for Group 1 boilers.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... PROGRAMS (CONTINUED) ACID RAIN NITROGEN OXIDES EMISSION REDUCTION PROGRAM § 76.5 NOX emission limitations..., the date on which the unit is required to meet Acid Rain emission reduction requirements for SO2, the... 404(d) of the Act, the date the unit is required to meet Acid Rain emissions reduction...

  1. 40 CFR 76.5 - NOX emission limitations for Group 1 boilers.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... PROGRAMS (CONTINUED) ACID RAIN NITROGEN OXIDES EMISSION REDUCTION PROGRAM § 76.5 NOX emission limitations..., the date on which the unit is required to meet Acid Rain emission reduction requirements for SO2, the... 404(d) of the Act, the date the unit is required to meet Acid Rain emissions reduction...

  2. 40 CFR 76.5 - NOX emission limitations for Group 1 boilers.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... PROGRAMS (CONTINUED) ACID RAIN NITROGEN OXIDES EMISSION REDUCTION PROGRAM § 76.5 NOX emission limitations..., the date on which the unit is required to meet Acid Rain emission reduction requirements for SO2, the... 404(d) of the Act, the date the unit is required to meet Acid Rain emissions reduction...

  3. NOx reduction methods and apparatuses

    DOEpatents

    Tonkyn, Russell G.; Barlow, Stephan E.; Balmer, M. Lou; Maupin, Gary D.

    2004-10-26

    A NO.sub.x reduction method includes treating a first gas containing NO.sub.x, producing a second gas containing NO.sub.2, reducing a portion of the NO.sub.2 in the second gas to N.sub.2, and producing a third gas containing less NO.sub.x than the first gas, substantially all of the third gas NO.sub.x being NO. The method also includes treating the third gas, producing a fourth gas containing NO.sub.2, reducing a portion of the NO.sub.2 in the fourth gas to N.sub.2, and producing a fifth gas containing less NO.sub.x than the third gas, substantially all of the fifth gas NO.sub.x being NO. Treating the first and/or third gas can include treatment with a plasma. Reducing a portion of the NO.sub.2 in the second and/or fourth gas can include reducing with a catalyst. The method can further include controlling energy consumption of the plasmas independent of each other.

  4. Implications of diesel emissions control failures to emission factors and road transport NOx evolution

    NASA Astrophysics Data System (ADS)

    Ntziachristos, Leonidas; Papadimitriou, Giannis; Ligterink, Norbert; Hausberger, Stefan

    2016-09-01

    Diesel NOx emissions have been at the forefront of research and regulation scrutiny as a result of failures of late vehicle technologies to deliver on-road emissions reductions. The current study aims at identifying the actual emissions levels of late light duty vehicle technologies, including Euro 5 and Euro 6 ones. Mean NOx emission factor levels used in the most popular EU vehicle emission models (COPERT, HBEFA and VERSIT+) are compared with latest emission information collected in the laboratory over real-world driving cycles and on the road using portable emissions measurement systems (PEMS). The comparison shows that Euro 5 passenger car (PC) emission factors well reflect on road levels and that recently revealed emissions control failures do not call for any significant corrections. However Euro 5 light commercial vehicles (LCVs) and Euro 6 PCs in the 2014-2016 period exhibit on road emission levels twice as high as used in current models. Moreover, measured levels vary a lot for Euro 6 vehicles. Scenarios for future evolution of Euro 6 emission factors, reflecting different degree of effectiveness of emissions control regulations, show that total NOx emissions from diesel Euro 6 PC and LCV may correspond from 49% up to 83% of total road transport emissions in 2050. Unless upcoming and long term regulations make sure that light duty diesel NOx emissions are effectively addressed, this will have significant implications in meeting future air quality and national emissions ceilings targets.

  5. Radiative cooling in a flameholder for NOx reduction

    NASA Astrophysics Data System (ADS)

    Breidenthal, Robert; Krichtafovitch, Igor; Karkow, Doug; Colannino, Joseph

    2014-11-01

    Recent experiments have revealed dramatic reductions in NOx emissions using a ceramic honeycomb as a flameholder. A jet of fuel entrains and mixes air before entering the honeycomb. The honeycomb is positioned at a distance away from the jet nozzle such that the mixed fluid arriving at the upstream edge of the honeycomb is combustible. Combustion occurs within the honeycomb, transferring heat to the ceramic walls, which glow red hot. According to a simple physical model, radiation and thermal conduction transport energy toward the upstream end of the honeycomb, thereby heating the incident cold reactants to maintain combustion. The radiation also transports energy downstream and away from the honeycomb, toward a thermal load. This is an attractive characteristic in boiler applications, for example. Furthermore, the hot combustion products in intimate thermal contact with the walls of the radiating honeycomb are rapidly cooled, consistent with the low NOx emissions. Preliminary experiments with different honeycomb configurations are in accord with this model.

  6. Enhanced High Temperature Performance of NOx Reduction Catalyst Materials

    SciTech Connect

    Gao, Feng; Kim, Do Heui; Luo, Jinyong; Muntean, George G.; Peden, Charles HF; Howden, Ken; Currier, Neal; Kamasamudram, Krishna; Kumar, Ashok; Li, Junhui; Stafford, Randy; Yezerets, Aleksey; Castagnola, Mario; Chen, Hai Ying; Hess, Howard ..

    2012-12-31

    Two primary NOx after-treatment technologies have been recognized as the most promising approaches for meeting stringent NOx emission standards for diesel vehicles within the Environmental Protection Agency’s (EPA’s) 2007/2010 mandated limits, NOx Storage Reduction (NSR) and NH3 selective catalytic reduction (SCR); both are, in fact being commercialized for this application. However, in looking forward to 2015 and beyond with expected more stringent regulations, the continued viability of the NSR technology for controlling NOx emissions from lean-burn engines such as diesels will require at least two specific, significant and inter-related improvements. First, it is important to reduce system costs by, for example, minimizing the precious metal content while maintaining, even improving, performance and long-term stability. A second critical need for future NSR systems, as well as for NH3 SCR, will be significantly improved higher and lower temperature performance and stability. Furthermore, these critically needed improvements will contribute significantly to minimizing the impacts to fuel economy of incorporating these after-treatment technologies on lean-burn vehicles. To meet these objectives will require, at a minimum an improved scientific understanding of the following things: i) the various roles for the precious and coinage metals used in these catalysts; ii) the mechanisms for these various roles; iii) the effects of high temperatures on the active metal performance in their various roles; iv) mechanisms for higher temperature NOx storage performance for modified and/or alternative storage materials; v) the interactions between the precious metals and the storage materials in both optimum NOx storage performance and long term stability; vi) the sulfur adsorption and regeneration mechanisms for NOx reduction materials; vii) materials degradation mechanisms in CHA-based NH3 SCR catalysts. The objective of this CRADA project between PNNL and Cummins, Inc

  7. 40 CFR 76.5 - NOX emission limitations for Group 1 boilers.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... PROGRAMS (CONTINUED) ACID RAIN NITROGEN OXIDES EMISSION REDUCTION PROGRAM § 76.5 NOX emission limitations..., the date on which the unit is required to meet Acid Rain emission reduction requirements for SO2, the... subject to section 404(d) of the Act, the date the unit is required to meet Acid Rain emissions...

  8. NOx emissions from a Central California dairy

    NASA Astrophysics Data System (ADS)

    Hasson, Alam S.; Ogunjemiyo, Segun O.; Trabue, Steven; Ashkan, Shawn; Scoggin, Kenwood; Steele, Julie; Olea, Catalina; Middala, Srikar; Vu, Kennedy; Scruggs, Austen; Addala, Laxmi R.; Nana, Lucien

    2013-05-01

    Concentrations of NOx (NO + NO2) were monitored downwind from a Central California dairy facility during 2011 and 2012. NOx concentrations at the dairy were significantly higher than the background levels during August 2011 primarily due to the presence of elevated NO, but were indistinguishable from background concentrations during January and April 2012. A Gaussian plume model (AERMOD) and a Lagrangian back trajectory model (Wind Trax) were used to estimate the flux of NO from the dairy during August 2011 with the assumption that emissions were primarily from animal feed. NO emissions from silage were also directly measured from feed to provide additional insight into the sources. Isolation flux chamber measurements imply an NO flux from the feed of about 1.3 × 10-3 g m-2 h-1, but these relatively low fluxes are inconsistent with the elevated NO concentrations observed during August 2011. This implies that either the flux chamber method grossly underestimates the true NO emissions from feed, or that most of the ambient NO measured at the dairy is from other sources. Emissions from farm machinery may account for the NO concentrations observed. Animal feed thus appears to be a small contributor to NOx emissions within Central California.

  9. NOX REDUCTION FOR LEAN EXHAUST USING PLASMA ASSISTED CATALYSIS

    SciTech Connect

    Bhatt, B.

    2000-08-20

    Currently CARB estimates on road diesel vehicles contribute 50% of the NOX and 78% of the particulates being discharged from mobile sources. Diesel emissions obviously must be reduced if future air quality targets are to be met. A critical technological barrier exists because there are no commercial technologies available, which can reduce NOX from diesel (lean), exhaust containing 5-15% O2 concentration. One promising approach to reducing NOX and particulates from diesel exhaust is to use a combination of plasma with catalyst. Plasma can be generated thermally or non-thermally. Thermal plasma is formed by heating the system to an exceedingly high temperature (>2000 C). High temperature requirements for plasma makes thermal plasma inefficient and requires skillful thermal management and hence is considered impractical for mobile applications. Non-thermal plasma directs electrical energy into the creation of free electrons, which in turn react with gaseous species thus creating plasma. A combination of non-thermal plasma with catalysts can be referred to Plasma Assisted Catalysts or PAC. PAC technology has been demonstrated in stationary sources where non-thermal plasma catalysis is carried out in presence of NH3 as a reductant. In stationary applications NO is oxidized to HNO3 and then into ammonium nitrate where it is condensed and removed. This approach is impractical for mobile application because of the ammonia requirement and the ultimate mechanism by which NOX is removed. However, if a suitable catalyst can be found which can use onboard fuel as reductant then the technology holds a considerable promise. NOX REDUCTION FOR LEAN EXHAUST USING PLASMA ASSISTED CATALYSIS Ralph Slone, B. Bhatt and Victor Puchkarev NOXTECH INC. In addition to the development of an effective catalyst, a non-thermal plasma reactor needs be scaled and demonstrated along with a reliable and cost effective plasma power source and onboard HC source needs to be proven. Under the work

  10. NOx Emissions from a Lobed Fuel Injector/Burner

    NASA Technical Reports Server (NTRS)

    Mitchell, M. G.; Smith, L. L.; Karagozian, A. R.; Smith, O. I.

    1996-01-01

    The present experimental study examines the performance of a novel fuel injector/burner configuration with respect to reduction in nitrogen oxide NOx emissions. The lobed injector/burner is a device in which very rapid initial mixing of reactants can occur through strong streamwise vorticity generation, producing high fluid mechanical strain rates which can delay ignition and thus prevent the formation of stoichiometric diffusion flames. Further downstream of the rapid mixing region. this flowfield produces a reduced effective strain rate, thus allowing ignition to occur in a premixed mode, where it is possible for combustion to take place under locally lean conditions. potentially reducing NOx emissions from the burner. The present experiments compare NO/NO2/NOx emissions from a lobed fuel injector configuration with emissions from a straight fuel injector to determine the net effect of streamwise vorticity generation. Preliminary results show that the lobed injector geometry can produce lean premixed flame structures. while for comparable flow conditions, a straight fuel injector geometry produces much longer. sooting diffusion flames or slightly rich pre-mixed flames. NO measurements show that emissions from a lobed fuel injector/burner can be made significantly lower than from a straight fuel injector under comparable flow conditions.

  11. DEVELOPMENT OF A NOVEL RADIATIVELY/CONDUCTIVELY STABILIZED BURNER FOR SIGNIFICANT REDUCTION OF NOx EMISSIONS AND FOR ADVANCING THE MODELING AND UNDERSTANDING OF PULVERIZED COAL COMBUSTION AND EMISSIONS

    SciTech Connect

    Noam Lior; Stuart W. Churchill

    2003-10-01

    the Gordon Conference on Modern Development in Thermodynamics. The results obtained are very encouraging for the development of the RCSC as a commercial burner for significant reduction of NO{sub x} emissions, and highly warrants further study and development.

  12. Plasma-assisted combustion technology for NOx reduction in industrial burners.

    PubMed

    Lee, Dae Hoon; Kim, Kwan-Tae; Kang, Hee Seok; Song, Young-Hoon; Park, Jae Eon

    2013-10-01

    Stronger regulations on nitrogen oxide (NOx) production have recently promoted the creation of a diverse array of technologies for NOx reduction, particularly within the combustion process, where reduction is least expensive. In this paper, we discuss a new combustion technology that can reduce NOx emissions within industrial burners to single-digit parts per million levels without employing exhaust gas recirculation or other NOx reduction mechanisms. This new technology uses a simple modification of commercial burners, such that they are able to perform plasma-assisted staged combustion without altering the outer configuration of the commercial reference burner. We embedded the first-stage combustor within the head of the commercial reference burner, where it operated as a reformer that could host a partial oxidation process, producing hydrogen-rich reformate or synthesis gas product. The resulting hydrogen-rich flow then ignited and stabilized the combustion flame apart from the burner rim. Ultimately, the enhanced mixing and removal of hot spots with a widened flame area acted as the main mechanisms of NOx reduction. Because this plasma burner acted as a low NOx burner and was able to reduce NOx by more than half compared to the commercial reference burner, this methodology offers important cost-effective possibilities for NOx reduction in industrial applications.

  13. Influence of Ceria on the NOx Storage/Reduction Behavior of Lean NOx Trap Catalysts

    SciTech Connect

    Ji, Yaying; Choi, Jae-Soon; Toops, Todd J; Crocker, Dr. Mark; Naseri, Mojghan

    2008-01-01

    The effect of La2O3-stabilized ceria incorporation on the functioning of fully formulated lean NOx trap catalysts was investigated. Monolithic catalysts were prepared, corresponding to loadings of 0, 50 and 100 g CeO2/L, together with a catalyst containing 100 g/L of ceria-zirconia (Ce0.7Zr0.3O2). Loadings of the other main components (Pt, Rh and BaO) were held constant. Catalyst evaluation was performed on a bench flow reactor under simulated diesel exhaust conditions, employing NOx storage/reduction cycles. NOx storage efficiency in the temperature range 150-350 C was observed to increase with ceria loading, resulting in higher NOx conversion levels. At 150 C, high rich phase NOx slip was observed for all of the catalysts, resulting from an imbalance in the rates of nitrate decomposition and NOx reduction. Optimal NOx conversion was obtained in the range 250-350 C for all the catalysts, while at 450 C high rich phase NOx slip from the most highly loaded ceria-containing catalyst resulted in lower NOx conversion than for the ceria-free formulation. N2O was the major NOx reduction product at 150 C over all of the catalysts, although low NOx conversion levels limited the N2O yield. At higher temperatures N2 was the main product of NOx reduction, although NH3 formation was also observed. Selectivity to NH3 decreased with increasing ceria loading, indicating that NH3 is consumed by reaction with stored oxygen in the rear of the catalyst.

  14. Maximize the benefit of SNCR: Combine SNCR with combustion optimization and achieve 50% NOx reduction from a low NOx burner baseline

    SciTech Connect

    Trego, P.; Schindler, E.

    2000-07-01

    PECO Energy Company operates one coal fired boiler at its Cromby Generating Facility. Cromby Unit 1 is a B and W front fired unit rated at 160 MW. The units boiler has been retrofitted with low NOx burners and overfire air ports. Due to NOx allowance pricing, PECO began evaluating options for reducing Cromby's NOx emissions. SNCR was evaluated at the best option for the plant even though the furnace exit temperatures and CO were high at practical injection locations. RJM Corporation, a Fuel Tech NOxOUT{trademark} Implementer, was selected to supply the system because of their extensive experience in solving combustion problems and applying NOxOUT SNCR systems on utility boilers. In order to reduce emissions during the 1999 NOx season, the deadline for an operational system was set at June 2nd. The project was issued on a fast track schedule starting February 2, 1999. The boiler was started up on June 2 on schedule after a six week maintenance outage. The project's 25% NOx reduction target was achieved after two weeks of combustion optimization. Combustion optimization was followed by NOxOUT A reagent injection system optimization which resulted in a 50% combined NOx reduction. Other benefits included a reduction in CO to less than 100 ppm and a 33% reduction in LOI.

  15. NOx Emissions Performance and Correlation Equations for a Multipoint LDI Injector

    NASA Technical Reports Server (NTRS)

    He, Zhuohui J.; Chang, Clarence T.; Follen, Caitlin E.

    2014-01-01

    Lean Direct Injection (LDI) is a combustor concept that reduces nitrogen oxides (NOx) emissions. This paper looks at a 3-zone multipoint LDI concept developed by Parker Hannifin Corporation. The concept was tested in a flame-tube test facility at NASA Glenn Research Center. Due to test facility limitations, such as inlet air temperature and pressure, the flame-tube test was not able to cover the full set of engine operation conditions. Three NOx correlation equations were developed based on assessing NOx emissions dependencies on inlet air pressure (P3), inlet air temperature (T3), and fuel air equivalence ratio (?) to estimate the NOx emissions at the unreachable high engine power conditions. As the results, the NOx emissions are found to be a strong function of combustion inlet air temperature and fuel air equivalence ratio but a weaker function of inlet air pressure. With these three equations, the NOx emissions performance of this injector concept is calculated as a 66 percent reduction relative to the ICAO CAEP-6 standard using a 55:1 pressure-ratio engine cycle. Uncertainty in the NOx emissions estimation increases as the extrapolation range departs from the experimental conditions. Since maximum inlet air pressure tested was less than 50 percent of the full power engine inlet air pressure, a future experiment at higher inlet air pressure conditions is needed to confirm the NOx emissions dependency on inlet air pressure.

  16. NOx Emissions Performance and Correlation Equations for a Multipoint LDI Injector

    NASA Technical Reports Server (NTRS)

    He, Zhuohui J.; Chang, Clarence T.; Follen, Caitlin E.

    2014-01-01

    Lean Direct Injection (LDI) is a combustor concept that reduces nitrogen oxides (NOx) emissions. This paper looks at a 3-zone multipoint LDI concept developed by Parker Hannifin Corporation. The concept was tested in a flame-tube test facility at NASA Glenn Research Center. Due to test facility limitations, such as inlet air temperature and pressure, the flame-tube test was not able to cover the full set of engine operation conditions. Three NOx correlation equations were developed based on assessing NOx emissions dependencies on inlet air pressure (P3), inlet air temperature (T3), and fuel air equivalence ratio (phi) to estimate the NOx emissions at the unreachable high engine power conditions. As the results, the NOx emissions are found to be a strong function of combustion inlet air temperature and fuel air equivalence ratio but a weaker function of inlet air pressure. With these three equations, the NOx emissions performance of this injector concept is calculated as a 66 percent reduction relative to the ICAO CAEP-6 standard using a 55:1 pressure-ratio engine cycle. Uncertainty in the NOx emissions estimation increases as the extrapolation range departs from the experimental conditions. Since maximum inlet air pressure tested was less than 50 percent of the full power engine inlet air pressure, a future experiment at higher inlet air pressure conditions is needed to confirm the NOx emissions dependency on inlet air pressure.

  17. NOx Emissions Performance and Correlation Equations for a Multipoint LDI Injector

    NASA Technical Reports Server (NTRS)

    He, Zhuohui Joe; Chang, Clarence T.; Follen, Caitlin E.

    2015-01-01

    Lean Direct Injection (LDI) is a combustor concept that reduces nitrogen oxides (NOx) emissions.This paper looks at a 3-zone multipoint LDI concept developed by Parker Hannifin Corporation. The concept was tested in a flame-tube test facility at NASA Glenn Research Center. Due to test facility limitations, such as inlet air temperature and pressure, the flame-tube test was not able to cover the full set of engine operation conditions. Three NOx correlation equations were developed based on assessing NOx emissions dependencies on inlet air pressure (P3), inlet air temperature (T3), and fuel air equivalence ratio(theta) to estimate the NOx emissions at the unreachable high engine power conditions. As the results, the NOx emissions are found to be a strong function of combustion inlet air temperature and fuel air equivalence ratio but a weaker function of inlet air pressure. With these three equations, the NOx emissions performance of this injector concept is calculated as a 66 reduction relative to the ICAO CAEP-6 standard using a 55:1 pressure-ratio engine cycle. Uncertainty in the NOx emissions estimation increases as the extrapolation range departs from the experimental conditions. Since maximum inlet air pressure tested was less than 50 of the full power engine inlet air pressure, a future experiment at higher inlet air pressure conditions is needed to confirm the NOx emissions dependency on inlet air pressure.

  18. NOx Emissions Performance and Correlation Equations for a Multipoint LDI Injector

    NASA Technical Reports Server (NTRS)

    He, Zhuohui J.; Chang, Clarence T.; Follen, Caitlin E.

    2015-01-01

    Lean Direct Injection (LDI) is a combustor concept that reduces nitrogen oxides (NOx) emissions. This paper looks at a 3-zone multipoint LDI concept developed by Parker Hannifin Corporation. The concept was tested in a flame-tube test facility at NASA Glenn Research Center. Due to test facility limitations, such as inlet air temperature and pressure, the flame-tube test was not able to cover the full set of engine operation conditions. Three NOx correlation equations were developed based on assessing NOx emissions dependencies on inlet air pressure (P3), inlet air temperature (T3), and fuel air equivalence ratio (?) to estimate the NOx emissions at the unreachable high engine power conditions. As the results, the NOx emissions are found to be a strong function of combustion inlet air temperature and fuel air equivalence ratio but a weaker function of inlet air pressure. With these three equations, the NOx emissions performance of this injector concept is calculated as a 66% reduction relative to the ICAO CAEP-6 standard using a 55:1 pressure-ratio engine cycle. Uncertainty in the NOx emissions estimation increases as the extrapolation range departs from the experimental conditions. Since maximum inlet air pressure tested was less than 50% of the full power engine inlet air pressure, a future experiment at higher inlet air pressure conditions is needed to confirm the NOx emissions dependency on inlet air pressure.

  19. Nox reduction system utilizing pulsed hydrocarbon injection

    DOEpatents

    Brusasco, Raymond M.; Penetrante, Bernardino M.; Vogtlin, George E.; Merritt, Bernard T.

    2001-01-01

    Hydrocarbon co-reductants, such as diesel fuel, are added by pulsed injection to internal combustion engine exhaust to reduce exhaust NO.sub.x to N.sub.2 in the presence of a catalyst. Exhaust NO.sub.x reduction of at least 50% in the emissions is achieved with the addition of less than 5% fuel as a source of the hydrocarbon co-reductants. By means of pulsing the hydrocarbon flow, the amount of pulsed hydrocarbon vapor (itself a pollutant) can be minimized relative to the amount of NO.sub.x species removed.

  20. Verification of NOx emission inventories over North Korea.

    PubMed

    Kim, Na Kyung; Kim, Yong Pyo; Morino, Yu; Kurokawa, Jun-ichi; Ohara, Toshimasa

    2014-12-01

    In this study, the top-down NOx emissions estimated from satellite observations of NO2 vertical column densities over North Korea from 1996 to 2009 were analyzed. Also, a bottom-up NOx emission inventory from REAS 1.1 from 1980 to 2005 was analyzed with several statistics. REAS 1.1 was in good agreement with the top-down approach for both trend and amount. The characteristics of NOx emissions in North Korea were quite different from other developed countries including South Korea. In North Korea, emissions from industry sector was the highest followed by transportation sector in the 1980s. However, after 1990, the NOx emissions from other sector, mainly agriculture, became the 2nd highest. Also, no emission centers such as urban areas or industrial areas were distinctively observed. Finally, the monthly NOx emissions were high during the warm season.

  1. Nitrogen isotopic composition of coal-fired power plant NOx: influence of emission controls and implications for global emission inventories.

    PubMed

    Felix, J David; Elliott, Emily M; Shaw, Stephanie L

    2012-03-20

    Despite the potential use of δ(15)N as a tracer of NO(x) source contributions, prior documentation of δ(15)N of various NO(x) emission sources is exceedingly limited. This manuscript presents the first measurements of the nitrogen isotopic composition of NO(x) (δ(15)N-NO(x)) emitted from coal-fired power plants in the U.S. at typical operating conditions with and without the presence of selective catalytic reduction (SCR) and selective noncatalytic reduction (SNCR) technology. To accomplish this, a novel method for collection and isotopic analysis of coal-fired stack NO(x) emission samples was developed based on modifications of a historic U.S. EPA stack sampling method. At the power plants included in this study, large differences exist in the isotopic composition of NO(x) emitted with and without SCRs and SNCRs; further the isotopic composition of power plant NO(x) is higher than that of other measured NO(x) emission sources confirming its use as an environmental tracer. These findings indicate that gradual implementation of SCRs at power plants will result in an industry-wide increase in δ(15)N values of NO(x) and NO(y) oxidation products from this emission source.

  2. The challenge to NOx emission control for heavy-duty diesel vehicles in China

    NASA Astrophysics Data System (ADS)

    Wu, Y.; Zhang, S. J.; Li, M. L.; Ge, Y. S.; Shu, J. W.; Zhou, Y.; Xu, Y. Y.; Hu, J. N.; Liu, H.; Fu, L. X.; He, K. B.; Hao, J. M.

    2012-10-01

    China's new "Twelfth Five-Year Plan" set a target for total NOx emission reduction of 10% for the period of 2011-2015. Heavy-duty diesel vehicles (HDDVs) have been considered a major contributor to NOx emissions in China. Beijing initiated a comprehensive vehicle test program in 2008. This program included a sub-task for measuring on-road emission profiles of hundreds of HDDVs using portable emission measurement systems (PEMS). The major finding is that neither the on-road distance-specific (g km-1) nor brake-specific (g kWh-1) NOx emission factors for diesel buses and heavy-duty diesel trucks improved in most cases as emission standards became more stringent. For example, the average NOx emission factors for Euro II, Euro III and Euro IV buses are 11.3 ± 3.3 g km-1, 12.5 ± 1.3 g km-1, and 11.8 ± 2.0 g km-1, respectively. No statistically significant difference in NOx emission factors was observed between Euro II and III buses. Even for Euro IV buses equipped with SCR systems, the NOx emission factors are similar to Euro III buses. The data regarding real-time engine performance of Euro IV buses suggest the engine certification cycles did not reflect their real-world operating conditions. These new on-road test results indicate that previous estimates of total NOx emissions for HDDV fleet may be significantly underestimated. The new estimate in total NOx emissions for the Beijing HDDV fleet in 2009 is 37.0 Gg, an increase of 45% compared to the previous study. Further, we estimate that the total NOx emissions for the national HDDV fleet in 2009 are approximately 4.0 Tg, higher by 1.0 Tg (equivalent to 18% of total NOx emissions for vehicle fleet in 2009) than that estimated in the official report. This would also result in 4% increase in estimation of national anthropogenic NOx emissions. More effective control measures (such as promotion of CNG buses and a new in-use compliance testing program) are urged to secure the goal of total NOx mitigation for the HDDV

  3. 40 CFR 75.17 - Specific provisions for monitoring emissions from common, bypass, and multiple stacks for NOX...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... reduction program must also meet the provisions for monitoring NOX emission rate in §§ 75.71 and 75.72. (a... operating properly, as described in the quality assurance/quality control program for the unit, required by... record parametric data to verify the proper operation of the NOX add-on emission controls as described...

  4. 40 CFR 75.17 - Specific provisions for monitoring emissions from common, bypass, and multiple stacks for NOX...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... reduction program must also meet the provisions for monitoring NOX emission rate in §§ 75.71 and 75.72. (a... operating properly, as described in the quality assurance/quality control program for the unit, required by... record parametric data to verify the proper operation of the NOX add-on emission controls as described...

  5. Plasma-Chemical Hybrid NOx Reduction System for Commercial Cogeneration Boiler

    NASA Astrophysics Data System (ADS)

    Kuroki, Tomoyuki; Fujishima, Hidekatsu; Okubo, Masaaki

    Operation tests of the smoke-tube boiler emission NOx treatment plant which consists of a plasma ozonizer using a pressure swing adsorption (PSA) oxygen generator and silent discharge for indirect NO oxidation and a Na2SO3 chemical scrubber are carried out for cogeneration boilers which uses a city gas and heavy oil as a fuel based on our proposed plasma-chemical hybrid NOx reduction principle. It is clear that amount of NO removed is almost same as the amount of corresponding O3 concentration to oxidize NO regardless of fuels and flow rates of flue gas. After the relation between oxidation-reduction potential (ORP) and the NOx removal efficiency is obtained, continuous operation tests of this plant are performed. For gas firing boiler emission, the NO complete removal and the decrease in NOx from 32 ppm to 3 ppm are achieved for 300 min by keeping -30 mV of ORP. For the treatment of heavy oil boiler emission, the decrease in NOx from 90 ppm to less than 25 ppm is maintained for 250 min. It is demonstrated that the high NOx removal performance can be maintained for a long time by keeping the optimum value of ORP.

  6. Environmental Assessment for the Commercial Demonstration of the Low NOx Burner/Separated Over-Fire Air (LNB/SOFA) Integration System Emission Reduction Technology, Finney County, Kansas

    SciTech Connect

    n /a

    2003-03-11

    The U.S. Department of Energy (DOE) proposes to provide partial funding to the Sunflower Electric Power Corporation (Sunflower), to demonstrate the commercial application of Low-NO{sub x} Burner/Separated Over-Fire Air (LNB/SOFA) integration system to achieve NO{sub x} emission reduction to the level of 0.15 to 0.22 pounds per million British thermal units (lb/MM Btu). The proposed project station is Sunflower's 360 MW coal-fired generation station, Holcomb Unit No. 1 (Holcomb Station). The station, fueled by coal from Wyoming's Powder River Basin, is located near Garden City, in Finney County, Kansas. The period of performance is expected to last approximately 2 years. The Holcomb Station, Sunflower LNB/SOFA integrated system would be modified in three distinct phases to demonstrate the synergistic effect of layering NO{sub x} control technologies. Once modified, the station would demonstrate that a unit equipped with an existing low-NO{sub x} burner system can be retrofitted with a new separated over-fire air (SOFA) system, coal flow measurement and control, and enhanced combustion monitoring to achieve about 45 percent reduction in nitrogen oxides (NO{sub x}) emissions. The proposed project would demonstrate a technology alternative to Selective Catalytic Reduction (SCR) systems. While SCR does generally achieve high reductions in NO{sub x} emissions (from about 0.8 lb/MM to 0.12 lb/MM Btu), it does so at higher capital and operating cost, requires the extensive use of critical construction labor, requires longer periods of unit outage for deployment, and generally requires longer periods of time to complete shakedown and full-scale operation. Cost of the proposed project technology would be on the order of 15-25 percent of that for SCR, with consequential benefits derived from reductions in construction manpower requirements and periods of power outages. This proposed technology demonstration would generally be applicable to boilers using opposed-wall burners

  7. Discovery of New NOx Reduction Catalysts for CIDI Engines Using Combinatorial Techniques

    SciTech Connect

    Blint, Richard J

    2005-08-15

    This project for the discovery of new lean reduction NOx catalysts was initiated on August 16th, 2002 and is now into its fourth year. Several materials have already been identified as NOx reduction catalysts for possible future application. NOx reduction catalysts are a critical need in the North American vehicle market since these catalysts are needed to enable both diesels and lean gasoline engines to meet the 2007-2010 emission standards. Hydrocarbon selective catalytic reduction (SCR) is a preferred technology since it requires no infrastructure changes (as may be expected for urea SCR) and most likely has the simplest engine control strategy of the three proposed NOx reduction approaches. The use of fast throughput techniques and informatics greatly enhances the possibility of discovering new NOx reduction catalysts. Using fast throughput techniques this project has already screened over 3000 new materials and evaluates hundreds of new materials a month. Evaluating such a high number of new materials puts this approach into a very different paradigm than previous discovery approaches for new NOx reduction catalysts. With so much data on materials it is necessary to use statistical techniques to identify the potential catalysts and these statistical techniques are needed to optimize compositions of the multi-component materials that are identified under the program as possible new lean NOx catalysts. Several new materials have conversions in excess of 80% at temperatures above 300 C. That is more than twice the activity of previous HC SCR materials. These materials are candidates for emission control on heavy-duty systems (i.e.; over 8500 pounds gross weight). Tests of one of the downselected materials on an engine dynamometer show NOx reductions greater than 80% under some conditions even though the net NOx reductions on the HWFET and the US06 cycles were relatively low. The program is scheduled to continue until the end of the 2006 calendar year. Work in the

  8. Lean Gasoline Engine Reductant Chemistry During Lean NOx Trap Regeneration

    SciTech Connect

    Choi, Jae-Soon; Prikhodko, Vitaly Y; Partridge Jr, William P; Parks, II, James E; Norman, Kevin M; Huff, Shean P; Chambon, Paul H; Thomas, John F

    2010-01-01

    Lean NOx Trap (LNT) catalysts can effectively reduce NOx from lean engine exhaust. Significant research for LNTs in diesel engine applications has been performed and has led to commercialization of the technology. For lean gasoline engine applications, advanced direct injection engines have led to a renewed interest in the potential for lean gasoline vehicles and, thereby, a renewed demand for lean NOx control. To understand the gasoline-based reductant chemistry during regeneration, a BMW lean gasoline vehicle has been studied on a chassis dynamometer. Exhaust samples were collected and analyzed for key reductant species such as H2, CO, NH3, and hydrocarbons during transient drive cycles. The relation of the reductant species to LNT performance will be discussed. Furthermore, the challenges of NOx storage in the lean gasoline application are reviewed.

  9. Optimal ozone reduction policy design using adjoint-based NOx marginal damage information.

    PubMed

    Mesbah, S Morteza; Hakami, Amir; Schott, Stephan

    2013-01-01

    Despite substantial reductions in nitrogen oxide (NOx) emissions in the United States, the success of emission control programs in optimal ozone reduction is disputable because they do not consider the spatial and temporal differences in health and environmental damages caused by NOx emissions. This shortcoming in the current U.S. NOx control policy is explored, and various methodologies for identifying optimal NOx emission control strategies are evaluated. The proposed approach combines an optimization platform with an adjoint (or backward) sensitivity analysis model and is able to examine the environmental performance of the current cap-and-trade policy and two damage-based emissions-differentiated policies. Using the proposed methodology, a 2007 case study of 218 U.S. electricity generation units participating in the NOx trading program is examined. The results indicate that inclusion of damage information can significantly enhance public health performance of an economic instrument. The net benefit under the policy that minimizes the social cost (i.e., health costs plus abatement costs) is six times larger than that of an exchange rate cap-and-trade policy.

  10. The challenge to NOx emission control for heavy-duty diesel vehicles in China

    NASA Astrophysics Data System (ADS)

    Wu, Y.; Zhang, S. J.; Li, M. L.; Ge, Y. S.; Shu, J. W.; Zhou, Y.; Xu, Y. Y.; Hu, J. N.; Liu, H.; Fu, L. X.; He, K. B.; Hao, J. M.

    2012-07-01

    China's new "Twelfth Five-Year Plan" set a target for total NOx emission reduction of 10% for the period of 2011-2015. Heavy-duty diesel vehicles (HDDVs) have been considered a major contributor to NOx emissions in China. Beijing initiated a comprehensive vehicle test program in 2008. This program included a sub-task for measuring on-road emission profiles of hundreds of HDDVs using portable emission measurement systems (PEMS). The major finding is that neither the on-road distance-specific (g km -1) nor brake-specific (g kW h-1) NOx emission factors for diesel buses and heavy-duty diesel trucks improved in most cases as emission standards became more stringent. For example, the average NOx emission factors for Euro II, Euro III and Euro IV buses are 11.3±3.3 g km-1, 12.5± 1.3 g km-1, and 11.8±2.0 g km-1, respectively. No statistically significant difference in NOx emission factors was observed between Euro II and III buses. Even for Euro IV buses equipped with SCR systems, the NOx emission factors are similar to Euro III buses. The data regarding real-time engine performance of Euro IV buses suggest the engine certification cycles did not reflect their real-world operating conditions. These new on-road test results indicate that previous estimates of total NOx emissions for HDDV fleet may be significantly underestimated. The new estimate in total NOx emissions for the Beijing HDDV fleet in 2009 is 37.0 Gg, an increase of 45% compared to the previous study. Further, we estimate that the total NOx emissions for the national HDDV fleet in 2009 are approximately 4.0 Tg, higher by 1.0 Tg (equivalent to 18% of total NOx emissions for vehicle fleet in 2009) than that estimated in the official report. This would also result in 4% increase in estimation of national anthropogenic NOx emissions. More effective control measures (such as promotion of CNG buses and a new in-use compliance testing program) are urged to secure the goal of total NOxmitigation for the HDDV fleet

  11. Integrated diesel engine NOx reduction technology development

    SciTech Connect

    Hoelzer, J.; Zhu, J.; Savonen, C.L.; Kharas, K.C.C.; Bailey, O.H.; Miller, M.; Vuichard, J.

    1997-12-31

    The effectiveness of catalyst performance is a function of the inlet exhaust gas temperature, gas flow rate, concentration of NO{sub x} and oxygen, and reductant quantity and species. Given this interrelationship, it becomes immediately clear that an integrated development approach is necessary. Such an approach is taken in this project. As such, the system development path is directed by an engine-catalyst engineering team. Of the tools at the engine engineer`s disposal the real-time aspects of computer assisted subsystem modeling is valuable. It will continue to be the case as ever more subtle improvements are needed to meet competitive performance, durability, and emission challenges. A review of recent prototype engines has shown that considerable improvements to base diesel engine technology are being made. For example, HSDI NO{sub x} has been reduced by a factor of two within the past ten years. However, additional substantial NO{sub x}/PM reduction is still required for the future. A viable lean NO{sub x} catalyst would be an attractive solution to this end. The results of recent high and low temperature catalyst developments were presented. High temperature base metal catalysts have been formulated to produce very good conversion efficiency and good thermal stability, albeit at temperatures near the upper range of diesel engine operation. Low temperature noble metal catalysts have been developed to provide performance of promising 4-way control but need increased NO{sub x} reduction efficiency.

  12. Three-Dimensional Composite Nanostructures for Lean NOx Emission Control

    SciTech Connect

    Gao, Pu-Xian

    2013-07-31

    This final report to the Department of Energy (DOE) and National Energy Technology Laboratory (NETL) for DE-EE0000210 covers the period from October 1, 2009 to July 31, 2013. Under this project, DOE awarded UConn about $1,248,242 to conduct the research and development on a new class of 3D composite nanostructure based catalysts for lean NOx emission control. Much of the material presented here has already been submitted to DOE/NETL in quarterly technical reports. In this project, through a scalable solution process, we have successfully fabricated a new class of catalytic reactors, i.e., the composite nanostructure array (nano-array) based catalytic converters. These nanocatalysts, distinct from traditional powder washcoat based catalytic converters, directly integrate monolithic substrates together with nanostructures with well-defined size and shape during the scalable hydrothermal process. The new monolithic nanocatalysts are demonstrated to be able to save raw materials including Pt-group metals and support metal oxides by an order of magnitude, while perform well at various oxidation (e.g., CO oxidation and NO oxidation) and reduction reactions (H{sub 2} reduction of NOx) involved in the lean NOx emissions. The size, shape and arrangement of the composite nanostructures within the monolithic substrates are found to be the key in enabling the drastically reduced materials usage while maintaining the good catalytic reactivity in the enabled devices. The further understanding of the reaction kinetics associated with the unique mass transport and surface chemistry behind is needed for further optimizing the design and fabrication of good nanostructure array based catalytic converters. On the other hand, the high temperature stability, hydrothermal aging stability, as well as S-poisoning resistance have been investigated in this project on the nanocatalysts, which revealed promising results toward good chemical and mechanical robustness, as well as S

  13. Low Emissions Aftertreatment and Diesel Emissions Reduction

    SciTech Connect

    2005-05-27

    Detroit Diesel Corporation (DDC) has successfully completed a five-year Low Emissions Aftertreatment and Diesel Emissions Reduction (LEADER) program under a DOE project entitled: ''Research and Development for Compression-Ignition Direct-Injection Engines (CIDI) and Aftertreatment Sub-Systems''. The objectives of the LEADER Program were to: Demonstrate technologies that will achieve future federal Tier 2 emissions targets; and Demonstrate production-viable technical targets for engine out emissions, efficiency, power density, noise, durability, production cost, aftertreatment volume and weight. These objectives were successfully met during the course of the LEADER program The most noteworthy achievements in this program are listed below: (1) Demonstrated Tier 2 Bin 3 emissions target over the FTP75 cycle on a PNGV-mule Neon passenger car, utilizing a CSF + SCR system These aggressive emissions were obtained with no ammonia (NH{sub 3}) slip and a combined fuel economy of 63 miles per gallon, integrating FTP75 and highway fuel economy transient cycle test results. Demonstrated feasibility to achieve Tier 2 Bin 8 emissions levels without active NOx aftertreatment. (2) Demonstrated Tier 2 Bin 3 emissions target over the FTP75 cycle on a light-duty truck utilizing a CSF + SCR system, synergizing efforts with the DOE-DDC DELTA program. This aggressive reduction in tailpipe out emissions was achieved with no ammonia slip and a 41% fuel economy improvement, compared to the equivalent gasoline engine-equipped vehicle. (3) Demonstrated Tier 2 near-Bin 9 emissions compliance on a light-duty truck, without active NOx aftertreatment devices, in synergy with the DOE-DDC DELTA program. (4) Developed and applied advanced combustion technologies such as ''CLEAN Combustion{copyright}'', which yields simultaneous reduction in engine out NOx and PM emissions while also improving engine and aftertreatment integration by providing favorable exhaust species and temperature

  14. 40 CFR 76.7 - Revised NOX emission limitations for Group 1, Phase II boilers.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 17 2012-07-01 2012-07-01 false Revised NOX emission limitations for Group 1, Phase II boilers. 76.7 Section 76.7 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) ACID RAIN NITROGEN OXIDES EMISSION REDUCTION PROGRAM § 76.7 Revised...

  15. 40 CFR 76.7 - Revised NOX emission limitations for Group 1, Phase II boilers.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 16 2010-07-01 2010-07-01 false Revised NOX emission limitations for Group 1, Phase II boilers. 76.7 Section 76.7 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) ACID RAIN NITROGEN OXIDES EMISSION REDUCTION PROGRAM § 76.7 Revised...

  16. 40 CFR 76.7 - Revised NOX emission limitations for Group 1, Phase II boilers.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 16 2011-07-01 2011-07-01 false Revised NOX emission limitations for Group 1, Phase II boilers. 76.7 Section 76.7 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) ACID RAIN NITROGEN OXIDES EMISSION REDUCTION PROGRAM § 76.7 Revised...

  17. 40 CFR 76.7 - Revised NOX emission limitations for Group 1, Phase II boilers.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 17 2014-07-01 2014-07-01 false Revised NOX emission limitations for Group 1, Phase II boilers. 76.7 Section 76.7 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) ACID RAIN NITROGEN OXIDES EMISSION REDUCTION PROGRAM § 76.7 Revised...

  18. 40 CFR 76.7 - Revised NOX emission limitations for Group 1, Phase II boilers.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 17 2013-07-01 2013-07-01 false Revised NOX emission limitations for Group 1, Phase II boilers. 76.7 Section 76.7 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) ACID RAIN NITROGEN OXIDES EMISSION REDUCTION PROGRAM § 76.7 Revised...

  19. Effects of reducing SO2 and NOx emission from ships on air quality in Alaska

    NASA Astrophysics Data System (ADS)

    Tran, T. T.; Mölders, N.

    2011-12-01

    We performed simulations with the Alaska-adapted WRF/Chem using the same meteorological conditions of January 2000, but alternatively applying the emissions of 2000 (REF), emissions of 2000 with the ship-emission reductions for the planned North American Emission Contral Area (ECA) for SO2 only (ECA1) and SO2 and NOx (ECA2) that have been proposed by the International Maritime Organization for 2015. The analysis focused on the air quality along the international shipping lanes (ISL), in the ECA and over Alaska (AK). Our goal is to examine how the decreases in ship emissions in the ISL and ECA affect to air quality in Alaska. Our model results show that reducing SO2 and NOx ship-emissions reduces the concentration of sulfur and nitrogen compounds over Alaska despite of no changes in Alaska emissions. The reductions of pollutants over the ISL, ECA and AK stemming from concurrent SO2-NOx ship emission reductions are an order of magnitude of those stemming from SO2 reduction in ship emissions only. Reductions in sulfur compounds reach up to 14km while reductions of nitrogen compounds reach to only about 7km. Reductions of sulfate and nitrate in clouds are highest at the top of the boundary layer. Among the three regions of interest, strongest reductions occur over the ECA and ISL for sulfur and nitrogen compounds, respectively, since the ECA (ISL) has highest reductions of SO2 (NOx). The PM2.5 speciation partitioning over all three regions marginally changes when the ship emissions change. Sulfate is the major component of PM2.5 in all regions. Closer to the land, organic carbon (OC) partitioning is higher indicating the enhancing impacts of inland anthropogenic emissions to total PM2.5 concentrations over land.

  20. Importance of NOx control for peak ozone reduction in the Pearl River Delta region

    NASA Astrophysics Data System (ADS)

    Li, Ying; Lau, Alexis K. H.; Fung, Jimmy C. H.; Zheng, Junyu; Liu, Shawchen

    2013-08-01

    As major air pollutants and key precursors of several secondary air pollutants, nitrogen oxide (NOx) emissions are regulated in many countries. However, NOx control increases ozone concentrations when the ozone formation regime is volatile organic compound (VOC) limited. Although many studies have shown that NOx regulation reduces ozone levels over the long term, it is still of concern that NOx regulation increases short-term ozone levels in metropolitan regions, where ozone formation is found to be predominantly VOC-limited. The Pearl River Delta (PRD) in China is such a region. Our modeling sensitivity study shows that while NOx reduction in the PRD region may raise the mean ozone concentration, it can also decrease peak ozone levels. Similar changes are observed in the NOx and ozone data of the PRD regional air quality monitoring network (2006-2012), lending further credence to our results. In the model, this NOx control effect is a result of the complicated spatial and diurnal variations of the ozone formation regime. In most of the PRD region, the formation regime is VOC-limited in the morning and becomes NOx-limited during peak ozone hours. Although some areas are always VOC-limited, their ozone concentrations are relatively low, and the ozone increases caused by NOx reduction generally do not cause higher ozone levels than the region's original ozone maxima. Several control scenarios are simulated to evaluate the effects of various possible control regulations. Our results show that in addition to VOC control, NOx control can be effective for reducing peak ozone concentrations in the PRD region.

  1. NOX REMOVAL WITH COMBINED SELECTIVE CATALYTIC REDUCTION AND SELECTIVE NONCATALYTIC REDUCTION: PILOT- SCALE TEST RESULTS

    EPA Science Inventory

    Pilot-scale tests were conducted to develop a combined nitrogen oxide (NOx) reduction technology using both selective catalytic reduction (SCR) and selective noncatalytic reduction (SNCR). A commercially available vanadium-and titatnium-based composite honeycomb catalyst and enh...

  2. High Pressure Low NOx Emissions Research: Recent Progress at NASA Glenn Research Center

    NASA Technical Reports Server (NTRS)

    Chi-Ming, Lee; Tacina, Kathleen M.; Wey, Changlie

    2007-01-01

    In collaboration with U.S. aircraft engine companies, NASA Glenn Research Center has contributed to the advancement of low emissions combustion systems. For the High Speed Research Program (HSR), a 90% reduction in nitrogen oxides (NOx) emissions (relative to the then-current state of the art) has been demonstrated in sector rig testing at General Electric Aircraft Engines (GEAE). For the Advanced Subsonic Technology Program (AST), a 50% reduction in NOx emissions relative to the 1996 International Civil Aviation Organization (ICAO) standards has been at demonstrated in sector rigs at both GEAE and Pratt & Whitney (P&W). During the Ultra Efficient Engine Technology Program (UEET), a 70% reduction in NOx emissions, relative to the 1996 ICAO standards, was achieved in sector rig testing at Glenn in the world class Advanced Subsonic Combustion Rig (ASCR) and at contractor facilities. Low NOx combustor development continues under the Fundamental Aeronautics Program. To achieve these reductions, experimental and analytical research has been conducted to advance the understanding of emissions formation in combustion processes. Lean direct injection (LDI) concept development uses advanced laser-based non-intrusive diagnostics and analytical work to complement the emissions measurements and to provide guidance for concept improvement. This paper describes emissions results from flametube tests of a 9- injection-point LDI fuel/air mixer tested at inlet pressures up to 5500 kPa. Sample results from CFD and laser diagnostics are also discussed.

  3. 40 CFR 97.154 - Compliance with CAIR NOX emissions limitation.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 22 2013-07-01 2013-07-01 false Compliance with CAIR NOX emissions... PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS CAIR NOX Allowance Tracking System § 97.154 Compliance with CAIR NOX emissions limitation. (a) Allowance...

  4. 40 CFR 96.154 - Compliance with CAIR NOX emissions limitation.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 21 2011-07-01 2011-07-01 false Compliance with CAIR NOX emissions... PROGRAMS (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS FOR STATE IMPLEMENTATION PLANS CAIR NOX Allowance Tracking System § 96.154 Compliance with CAIR NOX emissions...

  5. 40 CFR 97.354 - Compliance with CAIR NOX emissions limitation.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 21 2011-07-01 2011-07-01 false Compliance with CAIR NOX emissions... PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS CAIR NOX Ozone Season Allowance Tracking System § 97.354 Compliance with CAIR NOX emissions limitation....

  6. 40 CFR 97.154 - Compliance with CAIR NOX emissions limitation.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 21 2011-07-01 2011-07-01 false Compliance with CAIR NOX emissions... PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS CAIR NOX Allowance Tracking System § 97.154 Compliance with CAIR NOX emissions limitation. (a) Allowance...

  7. 40 CFR 97.354 - Compliance with CAIR NOX emissions limitation.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 22 2013-07-01 2013-07-01 false Compliance with CAIR NOX emissions... PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS CAIR NOX Ozone Season Allowance Tracking System § 97.354 Compliance with CAIR NOX emissions limitation....

  8. 40 CFR 97.154 - Compliance with CAIR NOX emissions limitation.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 22 2012-07-01 2012-07-01 false Compliance with CAIR NOX emissions... PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS CAIR NOX Allowance Tracking System § 97.154 Compliance with CAIR NOX emissions limitation. (a) Allowance...

  9. 40 CFR 97.354 - Compliance with CAIR NOX emissions limitation.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 22 2012-07-01 2012-07-01 false Compliance with CAIR NOX emissions... PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS CAIR NOX Ozone Season Allowance Tracking System § 97.354 Compliance with CAIR NOX emissions limitation....

  10. 40 CFR 96.154 - Compliance with CAIR NOX emissions limitation.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 22 2012-07-01 2012-07-01 false Compliance with CAIR NOX emissions... PROGRAMS (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS FOR STATE IMPLEMENTATION PLANS CAIR NOX Allowance Tracking System § 96.154 Compliance with CAIR NOX emissions...

  11. Assimilated inversion of NOx emissions over east Asia using OMI NO2 column measurements

    NASA Astrophysics Data System (ADS)

    Zhao, Chun; Wang, Yuhang

    2009-03-01

    Assimilated inversion on a daily basis using OMI tropospheric NO2 columns is developed and applied in a regional chemical transport model (REAM) to constrain fossil fuel (FF) NOx emissions over east Asia in 2007. The iterative nature of the assimilated inversion improves upon the widely used monthly-mean inversion by accounting for the chemical feedbacks of changed NOx emissions and reducing the dependence of the a priori emissions. The assimilated a posteriori emissions from FF combustion over east Asia are 9.5 Tg N/yr comparable to 10.9 Tg N/yr of the a priori. Significant changes in the spatial distribution of FF NOx emissions are found in the assimilated inversion from the a priori or monthly-mean inversion. The assimilated inversion shows that the a priori FF NOx emission inventory tends to overestimate the emissions over the economically developed areas and underestimate over the underdeveloped areas in East China, which may reflect in part FF NOx emission reductions resulting from the urban-centric air quality controls in China.

  12. NOx Emissions from Diesel Passenger Cars Worsen with Age.

    PubMed

    Chen, Yuche; Borken-Kleefeld, Jens

    2016-04-01

    Commonly, the NOx emissions rates of diesel vehicles have been assumed to remain stable over the vehicle's lifetime. However, there have been hardly any representative long-term emission measurements. Here we present real-driving emissions of diesel cars and light commercial vehicles sampled on-road over 15 years in Zurich/Switzerland. Results suggest deterioration of NOx unit emissions for Euro 2 and Euro 3 diesel technologies, while Euro 1 and Euro 4 technologies seem to be stable. We can exclude a significant influence of high-emitting vehicles. NOx emissions from all cars and light commercial vehicles in European emission inventories increase by 5-10% accounting for the observed deterioration, depending on the country and its share of diesel cars. We suggest monitoring the stability of emission controls particularly for high-mileage light commercial as well as heavy-duty vehicles.

  13. NOx Emissions from Diesel Passenger Cars Worsen with Age.

    PubMed

    Chen, Yuche; Borken-Kleefeld, Jens

    2016-04-01

    Commonly, the NOx emissions rates of diesel vehicles have been assumed to remain stable over the vehicle's lifetime. However, there have been hardly any representative long-term emission measurements. Here we present real-driving emissions of diesel cars and light commercial vehicles sampled on-road over 15 years in Zurich/Switzerland. Results suggest deterioration of NOx unit emissions for Euro 2 and Euro 3 diesel technologies, while Euro 1 and Euro 4 technologies seem to be stable. We can exclude a significant influence of high-emitting vehicles. NOx emissions from all cars and light commercial vehicles in European emission inventories increase by 5-10% accounting for the observed deterioration, depending on the country and its share of diesel cars. We suggest monitoring the stability of emission controls particularly for high-mileage light commercial as well as heavy-duty vehicles. PMID:26886254

  14. METHANE de-NOX process as a NO{sub x} reduction technology for stoker boilers

    SciTech Connect

    Rabovitser, I.; Roberts, M.; Chan, I.; Loviska, T.; Morrow, R.; Bonner, T.; Hall, D.

    1996-12-31

    The most common NO{sub x} control technology utilized in stokers is selective noncatalytic reduction (SNCR) systems. The natural gas industry has developed the patented METHANE de-NOX reburning process for stokers to reduce NO{sub x} emissions to the levels set by current EPA regulations without increasing the levels of other undesirable emissions. In contrast to conventional reburning, where the reburn fuel is injected above the combustion zone to create a fuel-rich reburn zone, with METHANE de-NOX, natural gas is injected directly into the combustion zone above the grate; this results in a reduction of NO{sub x} formed in the coal bed and also limits its formation through decomposition of the NO{sub x} precursors to form molecular nitrogen rather than nitrogen oxides. The METHANE de-NOX process was field tested at the Olmsted County waste-to-energy facility in Rochester, Minnesota, and at an incineration plant in Japan. Compared to baseline levels, about 60% NO{sub x} reduction and an increase in boiler efficiency were achieved. IGT, Detroit Stoker Company, and Cogentrix are presently demonstrating the METHANE de-NOX technology on a coal-fired 390 MM Btu/h stoker boiler at a 240 MW cogeneration plant in Richmond, Virginia. Baseline tests were conducted which indicated that 50 to 60% NO{sub x} can be reduced by utilization of METHANE de-NOX.

  15. Evaluation of the impacts of biodiesel and second generation biofuels on NO(x) emissions for CARB diesel fuels.

    PubMed

    Hajbabaei, Maryam; Johnson, Kent C; Okamoto, Robert A; Mitchell, Alexander; Pullman, Marcie; Durbin, Thomas D

    2012-08-21

    The impact of biodiesel and second generation biofuels on nitrogen oxides (NO(x)) emissions from heavy-duty engines was investigated using a California Air Resources Board (CARB) certified diesel fuel. Two heavy-duty engines, a 2006 engine with no exhaust aftertreatment, and a 2007 engine with a diesel particle filter (DPF), were tested on an engine dynamometer over four different test cycles. Emissions from soy- and animal-based biodiesels, a hydrotreated renewable diesel, and a gas to liquid (GTL) fuel were evaluated at blend levels from 5 to 100%. NO(x) emissions consistently increased with increasing biodiesel blend level, while increasing renewable diesel and GTL blends showed NO(x) emissions reductions with blend level. NO(x) increases ranged from 1.5% to 6.9% for B20, 6.4% to 18.2% for B50, and 14.1% to 47.1% for B100. The soy-biodiesel showed higher NO(x) emissions increases compared to the animal-biodiesel. NO(x) emissions neutrality with the CARB diesel was achieved by blending GTL or renewable diesel fuels with various levels of biodiesel or by using di-tert-butyl peroxide (DTBP). It appears that the impact of biodiesel on NO(x) emissions might be a more important consideration when blended with CARB diesel or similar fuels, and that some form of NO(x) mitigation might be needed for biodiesel blends with such fuels.

  16. A Portable Emissions Measurement System (PEMS) study of NOx and primary NO2 emissions from Euro 6 diesel passenger cars and comparison with COPERT emission factors

    NASA Astrophysics Data System (ADS)

    O'Driscoll, Rosalind; ApSimon, Helen M.; Oxley, Tim; Molden, Nick; Stettler, Marc E. J.; Thiyagarajah, Aravinth

    2016-11-01

    Real world emissions of oxides of nitrogen (NOx) often greatly exceed those achieved in the laboratory based type approval process. In this paper the real world emissions from a substantial sample of the latest Euro 6 diesel passenger cars are presented with a focus on NOx and primary NO2. Portable Emissions Measurement System (PEMS) data is analysed from 39 Euro 6 diesel passenger cars over a test route comprised of urban and motorway sections. The sample includes vehicles installed with exhaust gas recirculation (EGR), lean NOx traps (LNT), or selective catalytic reduction (SCR). The results show wide variability in NOx emissions from 1 to 22 times the type approval limit. The average NOx emission, 0.36 (sd. 0.36) g km-1, is 4.5 times the Euro 6 limit. The average fraction primary NO2 (fNO2) is 44 (sd. 20) %. Higher emissions during the urban section of the route are attributed to an increased number of acceleration events. Comparisons between PEMS measurements and COPERT speed dependent emissions factors show PEMS measurements to be on average 1.6 times higher than COPERT estimates for NOx and 2.5 times for NO2. However, by removing the 5 most polluting vehicles average emissions were reduced considerably.

  17. ULTRA LOW NOx INTEGRATED SYSTEM FOR NOx EMISSION CONTROL FROM COAL-FIRED BOILERS

    SciTech Connect

    Galen H. Richards; Charles Q. Maney; Richard W. Borio; Robert D. Lewis

    2002-12-30

    ALSTOM Power Inc.'s Power Plant Laboratories, working in concert with ALSTOM Power's Performance Projects Group, has teamed with the U.S. Department of Energy's National Energy Technology Laboratory (DOE NETL) to conduct a comprehensive study to develop/evaluate low-cost, efficient NOx control technologies for retrofit to pulverized coal fired utility boilers. The objective of this project was to develop retrofit NOx control technology to achieve less than 0.15 lb/MMBtu NOx (for bituminous coals) and 0.10 lb/MMBtu NOx (for subbituminous coals) from existing pulverized coal fired utility boilers at a cost which is at least 25% less than SCR technology. Efficient control of NOx is seen as an important, enabling step in keeping coal as a viable part of the national energy mix in this century, and beyond. Presently 57% of U.S. electrical generation is coal based, and the Energy Information Agency projects that coal will maintain a lead in U.S. power generation over all other fuel sources for decades (EIA 1998 Energy Forecast). Yet, coal-based power is being strongly challenged by society's ever-increasing desire for an improved environment and the resultant improvement in health and safety. The needs of the electric-utility industry are to improve environmental performance, while simultaneously improving overall plant economics. This means that emissions control technology is needed with very low capital and operating costs. This project has responded to the industry's need for low NOx emissions by evaluating ideas that can be adapted to present pulverized coal fired systems, be they conventional or low NOx firing systems. The TFS 2000{trademark} firing system has been the ALSTOM Power Inc. commercial offering producing the lowest NOx emission levels. In this project, the TFS 2000{trademark} firing system served as a basis for comparison to other low NOx systems evaluated and was the foundation upon which refinements were made to further improve NOx emissions and

  18. Influence of satellite-derived photolysis rates and NOx emissions on Texas ozone modeling

    NASA Astrophysics Data System (ADS)

    Tang, W.; Cohan, D. S.; Pour-Biazar, A.; Lamsal, L. N.; White, A. T.; Xiao, X.; Zhou, W.; Henderson, B. H.; Lash, B. F.

    2015-02-01

    Uncertain photolysis rates and emission inventory impair the accuracy of state-level ozone (O3) regulatory modeling. Past studies have separately used satellite-observed clouds to correct the model-predicted photolysis rates, or satellite-constrained top-down NOx emissions to identify and reduce uncertainties in bottom-up NOx emissions. However, the joint application of multiple satellite-derived model inputs to improve O3 state implementation plan (SIP) modeling has rarely been explored. In this study, Geostationary Operational Environmental Satellite (GOES) observations of clouds are applied to derive the photolysis rates, replacing those used in Texas SIP modeling. This changes modeled O3 concentrations by up to 80 ppb and improves O3 simulations by reducing modeled normalized mean bias (NMB) and normalized mean error (NME) by up to 0.1. A sector-based discrete Kalman filter (DKF) inversion approach is incorporated with the Comprehensive Air Quality Model with extensions (CAMx)-decoupled direct method (DDM) model to adjust Texas NOx emissions using a high-resolution Ozone Monitoring Instrument (OMI) NO2 product. The discrepancy between OMI and CAMx NO2 vertical column densities (VCDs) is further reduced by increasing modeled NOx lifetime and adding an artificial amount of NO2 in the upper troposphere. The region-based DKF inversion suggests increasing NOx emissions by 10-50% in most regions, deteriorating the model performance in predicting ground NO2 and O3, while the sector-based DKF inversion tends to scale down area and nonroad NOx emissions by 50%, leading to a 2-5 ppb decrease in ground 8 h O3 predictions. Model performance in simulating ground NO2 and O3 are improved using sector-based inversion-constrained NOx emissions, with 0.25 and 0.04 reductions in NMBs and 0.13 and 0.04 reductions in NMEs, respectively. Using both GOES-derived photolysis rates and OMI-constrained NOx emissions together reduces modeled NMB and NME by 0.05, increases the model

  19. 40 CFR 96.354 - Compliance with CAIR NOX emissions limitation.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 22 2012-07-01 2012-07-01 false Compliance with CAIR NOX emissions... PROGRAMS (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS FOR STATE IMPLEMENTATION PLANS CAIR NOX Ozone Season Allowance Tracking System § 96.354 Compliance with CAIR NOX...

  20. 40 CFR 97.424 - Compliance with TR NOX Annual emissions limitation.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 22 2012-07-01 2012-07-01 false Compliance with TR NOX Annual... (CONTINUED) AIR PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS TR NOX Annual Trading Program § 97.424 Compliance with TR NOX Annual emissions limitation....

  1. The impact of satellite-adjusted NOx emissions on simulated NOx and O3 discrepancies in the urban and outflow areas of the Pacific and Lower Middle US

    NASA Astrophysics Data System (ADS)

    Choi, Y.

    2013-08-01

    We analyze the simulation results from a CMAQ model and GOME-2 NO2 retrievals over the United States for August~2009 to estimate the model-simulated biases of NOx concentrations over six geological regions (Pacific Coast = PC, Rocky Mountains = RM, Lower Middle = LM, Upper Middle = UM, Southeast = SE, Northeast = NE). By comparing GOME-2 NO2 columns to corresponding CMAQ NO2 columns, we produced satellite-adjusted NOx emission ("GOME2009") and compared baseline emission ("BASE2009") CMAQ simulations with GOME2009 CMAQ runs. We found that the latter exhibited decreases of -5.6%, -12.3%, -21.3%, and -15.9% over the PC, RM, LM, and SE regions, respectively, and increases of +2.3% and +10.0% over the UM and NE regions. In addition, we found that changes in NOx emissions generally mitigate discrepancies between the surface NOx concentrations of baseline CMAQ and those of AQS at EPA AQS stations (mean bias of +19.8% to -13.7% over PC, -13.8% to -36.7% over RM, +149.7% to -1.8% over LM, +22.5% to -7.8% over UM, +31.3% to -7.9% over SE, and +11.6% to +0.7% over NE). The relatively high simulated NOx biases from baseline CMAQ over LM (+149.7%) are likely the results of over-predictions of simulated NOx emissions, which could shed light on those from global/regional Chemical Transport Models. We also perform more detailed investigations on surface NOx and O3 concentrations in two urban and outflow areas, PC (e.g., Los Angeles, South Pasadena, Anaheim, La Habra and Riverside) and LM (e.g., Houston, Beaumont and Sulphur). From two case studies, we found that the GOME2009 emissions decreased surface NOx concentrations significantly in the urban areas of PC (up to 30 ppbv) and in those of LM (up to 10 ppbv) during the daytime and that simulated NOx concentrations from CMAQ with GOME2009 compare well to those of in-situ AQS observations. A significant reduction in NOx concentrations resulted in a comparable increase in surface O3 concentrations in the urban areas of PC (up to 30

  2. The impact of satellite-adjusted NOx emissions on simulated NOx and O3 discrepancies in the urban and outflow areas of the Pacific and Lower Middle US

    NASA Astrophysics Data System (ADS)

    Choi, Y.

    2014-01-01

    We analyze the simulation results from a CMAQ model and GOME-2 NO2 retrievals over the United States for August 2009 to estimate the model-simulated biases of NOx concentrations over six geological regions (Pacific Coast = PC, Rocky Mountains = RM, Lower Middle = LM, Upper Middle = UM, Southeast = SE, Northeast = NE). By comparing GOME-2 NO2 columns to corresponding CMAQ NO2 columns, we produced satellite-adjusted NOx emission ("GOME2009") and compared baseline emission ("BASE2009") CMAQ simulations with GOME2009 CMAQ runs. We found that the latter exhibited decreases of -5.6%, -12.3%, -21.3%, and -15.9 % over the PC, RM, LM, and SE regions, respectively, and increases of +2.3% and +10.0% over the UM and NE regions. In addition, we found that changes in NOx emissions generally mitigate discrepancies between the surface NOx concentrations of baseline CMAQ and those of AQS at EPA AQS stations (mean bias of +19.8% to -13.7% over PC, -13.8% to -36.7% over RM, +149.7% to -1.8% over LM, +22.5% to -7.8% over UM, +31.3% to -7.9% over SE, and +11.6% to +0.7% over NE). The relatively high simulated NOx biases from baseline CMAQ over LM (+149.7%) are likely the results of over-predictions of simulated NOx emissions, which could shed light on those from global/regional Chemical Transport Models. We also perform more detailed investigations on surface NOx and O3 concentrations in two urban and outflow areas, PC (e.g., Los Angeles, South Pasadena, Anaheim, La Habra and Riverside) and LM (e.g., Houston, Beaumont and Sulphur). From two case studies, we found that the GOME2009 emissions decreased surface NOx concentrations significantly in the urban areas of PC (up to 30 ppbv) and in those of LM (up to 10 ppbv) during the daytime and that simulated NOx concentrations from CMAQ with GOME2009 compare well to those of in-situ AQS observations. A significant reduction in NOx concentrations resulted in a comparable increase in surface O3 concentrations in the urban areas of PC (up to 30

  3. NOx emission estimates during the 2014 Youth Olympic Games in Nanjing

    NASA Astrophysics Data System (ADS)

    Ding, J.; van der A, R. J.; Mijling, B.; Levelt, P. F.; Hao, N.

    2015-08-01

    The Nanjing Government applied temporary environmental regulations to guarantee good air quality during the Youth Olympic Games (YOG) in 2014. We study the effect of those regulations by applying the emission estimate algorithm DECSO (Daily Emission estimates Constrained by Satellite Observations) to measurements of the Ozone Monitoring Instrument (OMI). We improved DECSO by updating the chemical transport model CHIMERE from v2006 to v2013 and by adding an Observation minus Forecast (OmF) criterion to filter outlying satellite retrievals due to high aerosol concentrations. The comparison of model results with both ground and satellite observations indicates that CHIMERE v2013 is better performing than CHIMERE v2006. After filtering the satellite observations with high aerosol loads that were leading to large OmF values, unrealistic jumps in the emission estimates are removed. Despite the cloudy conditions during the YOG we could still see a decrease of tropospheric NO2 column concentrations of about 32 % in the OMI observations when compared to the average NO2 columns from 2005 to 2012. The results of the improved DECSO algorithm for NOx emissions show a reduction of at least 25 % during the YOG period and afterwards. This indicates that air quality regulations taken by the local government have an effect in reducing NOx emissions. The algorithm is also able to detect an emission reduction of 10 % during the Chinese Spring Festival. This study demonstrates the capacity of the DECSO algorithm to capture the change of NOx emissions on a monthly scale. We also show that the observed NO2 columns and the derived emissions show different patterns that provide complimentary information. For example, the Nanjing smog episode in December 2013 led to a strong increase in NO2 concentrations without an increase in NOx emissions. Furthermore, DECSO gives us important information on the non-trivial seasonal relation between NOx emissions and NO2 concentrations on a local scale.

  4. DYNAMOMETER EVALUATION OF PLASMA-CATALYST FOR DIESEL NOX REDUCTION

    SciTech Connect

    Hoard, J; Schmieg, S; Brooks, D; Peden, C; Barlow, S; Tonkyn, R

    2003-08-24

    A three-stage plasma-catalyst system was developed and tested on an engine dynamometer. Previous laboratory testing suggested high NOx efficiency could be obtained. With hexene reductant added to the exhaust, over 90% NOx reduction was observed. However, with diesel or Fischer-Tropsch reductant the catalyst efficiency rapidly dropped off. Heating the catalyst in air removed brown deposit from the surface and restored conversion efficiency. Following the engine tests, the used catalysts were evaluated. BET surface area decreased, and TPD revealed significant storage. This storage appears to be partly unburned diesel fuel that can be removed by heating to around 250-300 C, and partly hydrocarbons bonded to the surface that remain in place until 450-500 C. Laboratory testing with propene reductant demonstrated that the catalyst regains efficiency slowly even when operating temperature does not exceed 300 C. This suggests that control strategies may be able to regenerate the catalyst by occasional moderate heating.

  5. COST OF SELECTIVE CATALYTIC REDUCTION (SCR) APPLICATION FOR NOX CONTROL ON COAL-FIRED BOILERS

    EPA Science Inventory

    The report provides a methodology for estimating budgetary costs associated with retrofit applications of selective catalytic reduction (SCR) technology on coal-fired boilers. SCR is a postcombustion nitrogen oxides (NOx) control technology capable of providing NOx reductions >90...

  6. Nox Reduction in a Fluidized Bed Reactor with Fe/ZSM-5 Catalyst and Propylene as Reductant

    NASA Astrophysics Data System (ADS)

    Yang, Terris; Bi, Xiaotao

    The performance of a fluidized bed catalytic reactor was investigated for NOx reduction using a Fe/ZSM-5 catalyst and propylene as the reducing agent. The effects of inlet NOx concentration, propylene to NOx molar ratio, flue gas oxygen concentration and fluidizing gas velocity on NOx conversion were studied using simulated flue gases. The results showed that the NOx conversion decreased with decreasing the inlet NOx concentration, and propylene to NOx molar ratio. The increase in flue gas oxygen concentration also imposed a significant negative impact. As the flue gas oxygen concentration increased, NOx reduction decreased while propylene conversion increased at a given propylene to NOx molar ratio, due to the oxidation of propylene in the presence of high oxygen concentration. The increase in fluidization gas velocity reduced the contact time between reactant and the catalyst particles due to the increased bubble size and bubble rise velocity. As a result, the NOx reduction decreased as the gas velocity increased.

  7. NOx Sensor for Direct Injection Emission Control

    SciTech Connect

    Betteridge, William J

    2006-02-28

    The Electricore/Delphi team continues to leverage the electrochemical planar sensor technology that has produced stoichiometric planar and wide range oxygen sensors as the basis for development of a NOx sensor. Zirconia cell technology with an integrated heater will provide the foundation for the sensor structure. Proven materials and packaging technology will help to ensure a cost-effective approach to the manufacture of this sensor. The electronics technique and interface is considered to be an area where new strategies need to be employed to produce higher S/N ratios of the NOx signal with emphasis on signal stability over time for robustness and durability Both continuous mode and pulse mode control techniques are being evaluated. Packaging the electronics requires careful design and circuit partitioning so that only the necessary signal conditioning electronics are coupled directly in the wiring harness, while the remainder is situated within the ECM for durability and costs reasons. This task continues to be on hold due to the limitation that the definition of the interface electronics was unavailable until very late in the project. The sense element is based on the amperometric method utilizing integrated alumina and zirconia ceramics. Precious metal electrodes are used to form the integrated heater, the cell electrodes and leads. Inside the actual sense cell structure, it is first necessary to separate NOx from the remaining oxygen constituents of the exhaust, without reducing the NOx. Once separated, the NOx will be measured using a measurement cell. Development or test coupons have been used to facilitate material selection and refinement, cell, diffusion barrier, and chamber development. The sense element currently requires elaborate interconnections. To facilitate a robust durable connection, mechanical and metallurgical connections are under investigation. Materials and process refinements continue to play an important role in the development of the

  8. Electrochemical NOx Sensor for Monitoring Diesel Emissions

    SciTech Connect

    Woo, L Y; Glass, R S

    2008-11-14

    % NO, balance NO{sub 2}. Since automotive exhaust sensors will probably be required to operate at temperatures > 600 C, NO is the dominant component in thermodynamic equilibrium and the target NOx species. Also, the use of upstream catalysts could further promote the conversion of NO{sub x} species to NO. Therefore, the focus of current work is to investigate the response to NO. Nevertheless, minimizing the sensitivity to a variety of competing species is important in order to obtain the accuracy necessary for achieving the emission limits. Mitigating the effect of interfering gases (e.g., O{sub 2}, water vapor, HCs, etc.) is an area of current study. For impedance metric NO{sub x} sensors, our previous work has demonstrated that the cross-sensitivity to O{sub 2} may be accounted for by comparing measurements at multiple frequencies. Other strategies for compensation are also being explored, including calibration using data from existing sensors located nearby. Our current work has made significant advances in terms of developing prototype sensors more suitable for commercialization. Also, dynamometer testing has provided real-world sensor performance data that will be useful in approaching potential suppliers to whom we can transfer the technology for commercialization. The advances are a direct result of understanding the sensing mechanisms responsible for impedance-based NO{sub x} sensing and the effect of materials choice and sensor design/geometry.

  9. Estimating Lightning NOx Emissions for Regional Air Quality Modeling

    NASA Astrophysics Data System (ADS)

    Holloway, T.; Scotty, E.; Harkey, M.

    2014-12-01

    Lightning emissions have long been recognized as an important source of nitrogen oxides (NOx) on a global scale, and an essential emission component for global atmospheric chemistry models. However, only in recent years have regional air quality models incorporated lightning NOx emissions into simulations. The growth in regional modeling of lightning emissions has been driven in part by comparisons with satellite-derived estimates of column NO2, especially from the Ozone Monitoring Instrument (OMI) aboard the Aura satellite. We present and evaluate a lightning inventory for the EPA Community Multiscale Air Quality (CMAQ) model. Our approach follows Koo et al. [2010] in the approach to spatially and temporally allocating a given total value based on cloud-top height and convective precipitation. However, we consider alternate total NOx emission values (which translate into alternate lightning emission factors) based on a review of the literature and performance evaluation against OMI NO2 for July 2007 conditions over the U.S. and parts of Canada and Mexico. The vertical distribution of lightning emissions follow a bimodal distribution from Allen et al. [2012] calculated over 27 vertical model layers. Total lightning NO emissions for July 2007 show the highest above-land emissions in Florida, southeastern Texas and southern Louisiana. Although agreement with OMI NO2 across the domain varied significantly depending on lightning NOx assumptions, agreement among the simulations at ground-based NO2 monitors from the EPA Air Quality System database showed no meaningful sensitivity to lightning NOx. Emissions are compared with prior studies, which find similar distribution patterns, but a wide range of calculated magnitudes.

  10. 40 CFR 96.354 - Compliance with CAIR NOX emissions limitation.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... IMPLEMENTATION PLANS CAIR NOX Ozone Season Allowance Tracking System § 96.354 Compliance with CAIR NOX emissions limitation. (a) Allowance transfer deadline. The CAIR NOX Ozone Season allowances are available to be deducted for compliance with a source's CAIR NOX Ozone Season emissions limitation for a control period...

  11. 40 CFR 96.354 - Compliance with CAIR NOX emissions limitation.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... IMPLEMENTATION PLANS CAIR NOX Ozone Season Allowance Tracking System § 96.354 Compliance with CAIR NOX emissions limitation. (a) Allowance transfer deadline. The CAIR NOX Ozone Season allowances are available to be deducted for compliance with a source's CAIR NOX Ozone Season emissions limitation for a control period...

  12. Lagrangian Hotspots of In-Use NOX Emissions from Transit Buses.

    PubMed

    Kotz, Andrew J; Kittelson, David B; Northrop, William F

    2016-06-01

    In-use, spatiotemporal NOX emissions were measured from a conventional powertrain transit bus and a series electric hybrid bus over gradients of route kinetic intensity and ambient temperature. This paper introduces a new method for identifying NOX emissions hotspots along a bus route using high fidelity Lagrangian vehicle data to explore spatial interactions that may influence emissions production. Our study shows that the studied transit buses emit higher than regulated emissions because on-route operation does not accurately represent the range of engine operation tested according to regulatory standards. Using the Lagrangian hotspot detection, we demonstrate that NOX hotspots occurred at bus stops, during cold starts, on inclines, and for accelerations. On the selected routes, bus stops resulted in 3.3 times the route averaged emissions factor in grams/km without significant dependence on bus type or climate. The buses also emitted 2.3 times the route averaged NOX emissions factor at the beginning of each route due to cold selective catalytic reduction aftertreatment temperature. The Lagrangian hotspot detection technique demonstrated here could be employed in future connected vehicles empowered by advances in computational power, data storage capability, and improved sensor technology to optimize emissions as a function of spatial location.

  13. Lagrangian Hotspots of In-Use NOX Emissions from Transit Buses.

    PubMed

    Kotz, Andrew J; Kittelson, David B; Northrop, William F

    2016-06-01

    In-use, spatiotemporal NOX emissions were measured from a conventional powertrain transit bus and a series electric hybrid bus over gradients of route kinetic intensity and ambient temperature. This paper introduces a new method for identifying NOX emissions hotspots along a bus route using high fidelity Lagrangian vehicle data to explore spatial interactions that may influence emissions production. Our study shows that the studied transit buses emit higher than regulated emissions because on-route operation does not accurately represent the range of engine operation tested according to regulatory standards. Using the Lagrangian hotspot detection, we demonstrate that NOX hotspots occurred at bus stops, during cold starts, on inclines, and for accelerations. On the selected routes, bus stops resulted in 3.3 times the route averaged emissions factor in grams/km without significant dependence on bus type or climate. The buses also emitted 2.3 times the route averaged NOX emissions factor at the beginning of each route due to cold selective catalytic reduction aftertreatment temperature. The Lagrangian hotspot detection technique demonstrated here could be employed in future connected vehicles empowered by advances in computational power, data storage capability, and improved sensor technology to optimize emissions as a function of spatial location. PMID:27135811

  14. Neural network boiler optimization of efficiency, emission, and reliability with TVA Kingston Unit 3 low NOx optimization test results

    SciTech Connect

    Chang, P.S.; Poston, J.M.; Schroech, K.A.; Hou, H.S.

    1995-12-31

    Boiler performance optimization includes the preservation of efficiency, emission, capacity, and reliability. Competitive pressures require cost reduction and environmental compliance. It is a challenge for utility personnel to balance these requirements often demand tradeoffs. The Clean Air Act Amendment requires utilities to reduce NOx emission. NOx emission reduction has often been accomplished by installation of new low NOx burners. Boiler tuning for NOx control can be used as an alternative to low NOx burner installation. Specifically in tangentially-fired boilers, boiler tuning can be very effective in NOx reduction. A PC-based computer software program was developed to assist the tuning process. This software, System Optimization Analysis Program (SOAP), is a neural network based code which uses the self-adaptation learning process, with an adaptive filter added for data noise control. SOAP can use historical data as the knowledge base and provides a fast optimal solution to adaptive control problems. SOAP was tested at TVA`s Kingston Unit 3 tangentially coal-fired furnace for NOx reduction. With a well-organized test plan, the optimized solution was reached with 16 tests at each test series load level. SOAP will be used for other plant equipment or system optimization, such as pulverizer performance, combustion system optimization, compared thermal performance design, and boiler tube leak detection and allocation.

  15. Will Euro 6 reduce the NOx emissions of new diesel cars? - Insights from on-road tests with Portable Emissions Measurement Systems (PEMS)

    NASA Astrophysics Data System (ADS)

    Weiss, Martin; Bonnel, Pierre; Kühlwein, Jörg; Provenza, Alessio; Lambrecht, Udo; Alessandrini, Stefano; Carriero, Massimo; Colombo, Rinaldo; Forni, Fausto; Lanappe, Gaston; Le Lijour, Philippe; Manfredi, Urbano; Montigny, Francois; Sculati, Mirco

    2012-12-01

    The nitrogen dioxide (NO2) pollution in urban areas of Europe can be partially attributed to the increasing market penetration of diesel cars that show higher distance-specific nitrogen oxides (NOx) emissions than gasoline cars. The on-road NOx emissions of diesel cars, furthermore, appear to exceed substantially applicable emissions standards. This observation raises concerns that the introduction of more stringent Euro 6 emissions standards in 2014 may not adequately reduce the distance-specific on-road NOx emissions of new diesel cars. We address the existing concerns by analyzing the gaseous emissions of one novel Euro 6 diesel car and six Euro 4-5 diesel cars with Portable Emissions Measurement Systems (PEMS). We find that the average on-road NOx emissions of the Euro 6 car (0.21 ± 0.09 g per kilometer [g km-1]) are considerably lower than those of the Euro 4 cars (0.76 ± 0.12 g km-1) and the Euro 5 cars (0.71 ± 0.30 g km-1). The selective catalytic reduction (SCR) system of the Euro 6 diesel car is suitable to limit NOx emissions during real-world on-road driving. Still, all tested cars, including the Euro 6 diesel car, exceed their NOx emissions standards on the road by 260 ± 130%. This finding suggests that the current type-approval procedure does not adequately capture the on-road NOx emissions of diesel cars. By introducing a complementary emissions test procedure that covers a wide range of normal operating conditions, the European legislative authorities can address this problem and ensure that Euro 6 will indeed deliver an adequate reduction in the NOx emissions of new diesel cars.

  16. Experimental Assessment of NOx Emissions from 73 Euro 6 Diesel Passenger Cars.

    PubMed

    Yang, Liuhanzi; Franco, Vicente; Mock, Peter; Kolke, Reinhard; Zhang, Shaojun; Wu, Ye; German, John

    2015-12-15

    Controlling nitrogen oxides (NOx) emissions from diesel passenger cars during real-world driving is one of the major technical challenges facing diesel auto manufacturers. Three main technologies are available for this purpose: exhaust gas recirculation (EGR), lean-burn NOx traps (LNT), and selective catalytic reduction (SCR). Seventy-three Euro 6 diesel passenger cars (8 EGR only, 40 LNT, and 25 SCR) were tested on a chassis dynamometer over both the European type-approval cycle (NEDC, cold engine start) and the more realistic Worldwide harmonized light-duty test cycle (WLTC version 2.0, hot start) between 2012 and 2015. Most vehicles met the legislative limit of 0.08 g/km of NOx over NEDC (average emission factors by technology: EGR-only 0.07 g/km, LNT 0.04 g/km, and SCR 0.05 g/km), but the average emission factors rose dramatically over WLTC (EGR-only 0.17 g/km, LNT 0.21 g/km, and SCR 0.13 g/km). Five LNT-equipped vehicles exhibited very poor performance over the WLTC, emitting 7-15 times the regulated limit. These results illustrate how diesel NOx emissions are not properly controlled under the current, NEDC-based homologation framework. The upcoming real-driving emissions (RDE) regulation, which mandates an additional on-road emissions test for EU type approvals, could be a step in the right direction to address this problem.

  17. Observations of the temperature dependent response of ozone to NOx reductions in the Sacramento, CA urban plume

    NASA Astrophysics Data System (ADS)

    Lafranchi, B. W.; Goldstein, A. H.; Cohen, R. C.

    2011-07-01

    Observations of NOx in the Sacramento, CA region show that mixing ratios decreased by 30 % between 2001 and 2008. Here we use an observation-based method to quantify net ozone (O3) production rates in the outflow from the Sacramento metropolitan region and examine the O3 decrease resulting from reductions in NOx emissions. This observational method does not rely on assumptions about detailed chemistry of ozone production, rather it is an independent means to verify and test these assumptions. We use an instantaneous steady-state model as well as a detailed 1-D plume model to aid in interpretation of the ozone production inferred from observations. In agreement with the models, the observations show that early in the plume, the NOx dependence for Ox (Ox = O3 + NO2) production is strongly coupled with temperature, suggesting that temperature-dependent biogenic VOC emissions and other temperature-related effects can drive Ox production between NOx-limited and NOx-suppressed regimes. As a result, NOx reductions were found to be most effective at higher temperatures over the 7 year period. We show that violations of the California 1-h O3 standard (90 ppb) in the region have been decreasing linearly with decreases in NOx (at a given temperature) and predict that reductions of NOx concentrations (and presumably emissions) by an additional 30 % (relative to 2007 levels) will eliminate violations of the state 1 h standard in the region. If current trends continue, a 30 % decrease in NOx is expected by 2012, and an end to violations of the 1 h standard in the Sacramento region appears to be imminent.

  18. Observations of the temperature dependent response of ozone to NOx reductions in the Sacramento, CA urban plume

    NASA Astrophysics Data System (ADS)

    Lafranchi, B. W.; Goldstein, A. H.; Cohen, R. C.

    2011-02-01

    Observations of NOx in the Sacramento, CA region show that mixing ratios decreased by 30% between 2001 and 2008. Here we use an observation-based method to quantify net ozone production rates in the outflow from the Sacramento metropolitan region and examine the O3 decrease resulting from reductions in NOx emissions. This observational method does not rely on assumptions about detailed chemistry of ozone production, rather it is an independent means to verify and test these assumptions. We use an instantaneous steady-state model as well as a detailed 1-D plume model to aid in interpretation of the ozone production inferred from observations. In agreement with the models, the observations show that early in the plume, the NOx dependence for Ox (Ox = O3 + NO2) production is strongly coupled with temperature, suggesting that temperature-dependent biogenic VOC emissions can drive Ox production between NOx-limited and NOx-suppressed regimes. As a result, NOx reductions were found to be most effective at higher temperatures over the 7 year period. We show that violations of the California 1-hour O3 standard (90 ppb) in the region have been decreasing linearly with decreases in NOx (at a given temperature) and predict that reductions of NOx concentrations (and presumably emissions) by an additional 30% (relative to 2007 levels) will eliminate violations of the state 1 h standard in the region. If current trends continue, a 30% decrease in NOx is expected by 2012, and an end to violations of the 1 h standard in the Sacramento region appears to be imminent.

  19. Dynamic evaluation of the CMAQv5.0 modeling system: Assessing the model’s ability to simulate ozone changes due to NOx emission reductions

    EPA Science Inventory

    Regional air quality models are frequently used for regulatory applications to predict changes in air quality due to changes in emissions or changes in meteorology. Dynamic model evaluation is thus an important step in establishing credibility in the model predicted pollutant re...

  20. Nitrogen Release from a NOx Storage and Reduction Catalyst

    SciTech Connect

    Tonkyn, Russell G.; Disselkamp, Robert S.; Peden, C. H.

    2006-04-30

    In a NOx storage and reduction (NSR) catalyst the release and reduction of NOx occurs over a very short period. The speed of the NOx release and reduction creates difficulties in analyzing the chemistry using normal analytical techniques, which are typically better suited to slower, steady state studies. We have investigated the time dependence of NO, NO2, NH3, N2O and N2 released by an NSR catalyst using a combination of FTIR and gas chromatographic techniques. Nitrogen was detected with the GC by using He rather than N2 as the background gas. The FTIR was used not only to monitor NO, NO2, NH3 and N2O, but also to establish cycle-to-cycle reproducibility. Under these conditions we used the GC to sample the effluent at multiple times over many lean-rich cycles. To the extent that the chemistry was truly periodic and reproducible, we obtained the time dependence of the release of nitrogen after the lean-to-rich transition. Similar information was obtained for O2, H2 and N2O. Combining the FTIR and GC data we obtained good cycle averaged nitrogen balances, indicating that all the major products were accounted for.

  1. Constraining NOx emissions using satellite NO2 measurements during 2013 DISCOVER-AQ Texas campaign

    NASA Astrophysics Data System (ADS)

    Souri, Amir Hossein; Choi, Yunsoo; Jeon, Wonbae; Li, Xiangshang; Pan, Shuai; Diao, Lijun; Westenbarger, David A.

    2016-04-01

    Reliable emission inventories are key to precisely model air pollutant concentrations. The relatively large reduction in NOx emissions that is well corroborated by satellite and in-situ observations over southeast Texas has resulted in discrepancies between observations and regional model simulations based on the National Emission Inventory (NEI) provided every three years in U.S. In this study, a Bayesian inversion of OMI tropospheric NO2 is conducted to update anthropogenic sources of NEI-2011 and soil-biogenic sources from BEIS3 (Biogenic Emission Inventory System version 3) over southeast Texas and west Louisiana during the 2013 DISCOVER-AQ Texas campaign. Results reveal that influences of the a priori profile used in OMI NO2 retrieval play a significant role in inconsistencies between model and satellite observations, which should be mitigated. A posteriori emissions are produced using the regional Community Multiscale Air Quality (CMAQ) model associated with Decoupled Direct Method (DDM) sensitivity analysis. The inverse estimate suggests a reduction in area (44%), mobile (30%), and point sources (60%) in high NOx areas (ENOx> 0.2 mol/s), and an increase in soil (∼52%) and area emissions (37%) in low NOx regions (ENOx< 0.02 mol/s). The reductions in anthropogenic sources in high NOx regions are attributed to both uncertainty of the priori and emissions policies, while increases in area and soil-biogenic emissions more likely resulted from under-estimation of ships emissions, and the Yienger- Levy scheme used in BEIS respectively. In order to validate the accuracy of updated NOx emissions, CMAQ simulation was performed and results were evaluated with independent surface NO2 measurements. Comparing to surface monitoring sites, we find improvements (before and after inverse modeling) for MB (1.95, -0.30 ppbv), MAB (3.65, 2.60 ppbv), RMSE (6.13, 4.37 ppbv), correlation (0.68, 0.69), and IOA (0.76, 0.82). The largest improvement is seen for morning time surface

  2. INDUSTRIAL BOILER RETROFIT FOR NOX CONTROL: COMBINED SELECTIVE NONCATALYTIC REDUCTION AND SELECTIVE CATALYTIC REDUCTION

    EPA Science Inventory

    The paper describes retrofitting and testing a 590 kW (2 MBtu/hr), oil-fired, three-pass, fire-tube package boiler with a combined selective noncatalytic reduction (SNCR) and selective catalytic reduction (SCR) system. The system demonstrated 85% nitrogen oxides (NOx) reduction w...

  3. Management of Southern California Edison`s NOx reduction program in a changing regulatory environment

    SciTech Connect

    Estrada, J.C.; Hoffman, D.R.; Johnson, L.W.; Kimoto, E.M.; Petrucelli, A.; Zamorano, D.

    1995-12-31

    The Southern California Edison Company (Edison) is a privately owned electric utility serving customers in a twelve county area of Southern California. Beginning in 1989, Edison initiated a major effort, within the Los Angeles air quality basin, to significantly reduce generating station emissions of the oxides of nitrogen (NOx). Since this program began, there have been numerous changes to the local, state and regional air quality regulations under which Edison operates. As a result, the program has evolved and expanded to include most of the fossil fuel generating units within the Edison service territory. Edison has attempted to meet these regulatory changes in the most cost effective manner. Using a variety of NOx control mechanisms, implemented throughout the period, Edison has taken a flexible approach to incorporating the latest technological developments. At the same time, lessons learned during each phase have been factored into succeeding phases of the program. Now that most of the NOx control devices have been installed and several years of operating experience have been gained, Edison would like to share that experience so that others might gain additional knowledge which may help in their NOx control programs. The major areas which will be addressed include (1) new developments, (2) contracting strategy, (3) project management and (4) an overview of operating experiences and results with Urea Injection (SNCR), Low NOx Burners (LNB), Flue Gas Recirculation and Selective Catalytic Reduction (SCR) systems.

  4. Demonstration of selective catalytic reduction (SCR) technology for the control of nitrogen oxide (NOx) emissions from high-sulfur coal-fired boilers

    SciTech Connect

    Not Available

    1991-11-01

    The objective of this project is to demonstrate and evaluate commercially available Selective Catalytic Reduction (SCR) catalysts from US, Japanese and European catalyst suppliers on a high-sulfur US coal-fired boiler. SCR is a post-combustion nitrogen oxide (NO{sub x}) control technology that involves injecting ammonia into the flue gas generated from coal combustion in an electric utility boiler. The flue gas containing ammonia is then passed through a reactor that contains a specialized catalyst. In the presence of the catalyst, the ammonia reacts with NO{sub x} to convert it to nitrogen and water vapor.

  5. 40 CFR 97.524 - Compliance with TR NOX Ozone Season emissions limitation.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 22 2013-07-01 2013-07-01 false Compliance with TR NOX Ozone Season... TR NOX Ozone Season Trading Program § 97.524 Compliance with TR NOX Ozone Season emissions limitation. (a) Availability for deduction for compliance. TR NOX Ozone Season allowances are available to...

  6. 40 CFR 97.524 - Compliance with TR NOX Ozone Season emissions limitation.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 22 2012-07-01 2012-07-01 false Compliance with TR NOX Ozone Season... TR NOX Ozone Season Trading Program § 97.524 Compliance with TR NOX Ozone Season emissions limitation. (a) Availability for deduction for compliance. TR NOX Ozone Season allowances are available to...

  7. 40 CFR 97.524 - Compliance with TR NOX Ozone Season emissions limitation.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 21 2014-07-01 2014-07-01 false Compliance with TR NOX Ozone Season... TR NOX Ozone Season Trading Program § 97.524 Compliance with TR NOX Ozone Season emissions limitation. (a) Availability for deduction for compliance. TR NOX Ozone Season allowances are available to...

  8. 40 CFR 96.154 - Compliance with CAIR NOX emissions limitation.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... IMPLEMENTATION PLANS CAIR NOX Allowance Tracking System § 96.154 Compliance with CAIR NOX emissions limitation... affect the liability of the owners and operators of the CAIR NOX source or the CAIR NOX units at the... submissions. (1) The Administrator may review and conduct independent audits concerning any submission...

  9. 40 CFR 96.154 - Compliance with CAIR NOX emissions limitation.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... IMPLEMENTATION PLANS CAIR NOX Allowance Tracking System § 96.154 Compliance with CAIR NOX emissions limitation... affect the liability of the owners and operators of the CAIR NOX source or the CAIR NOX units at the... submissions. (1) The Administrator may review and conduct independent audits concerning any submission...

  10. MENU OF NOX EMISSION CONTROL OPTIONS FOR COAL-FIRED ELECTRIC UTILITY BOILERS

    EPA Science Inventory

    The paper reviews NOx control options for coal-fired electric utility boilers. (NOTE: Acid Rain NOx regulations, the Ozone Transport Commission's NOx Budget Program, revision of the New Source Performance Standards (NSPS) for NOx emissions from utility sources, and Ozone Transpor...

  11. NOX EMISSION CONTROL OPTIONS FOR COAL-FIRED ELECTRIC UTILITY BOILERS

    EPA Science Inventory

    The paper reviews NOx control options for coal-fired electric utility boilers. (NOTE: Acid Rain NOx regulations, the Ozone Transport Commission's NOx Budget Program, revision of the New Source Performance Standards (NSPS) for NOx emissions from utility sources, and Ozone Transpor...

  12. Generation and Reduction of NOx on Air-Fed Ozonizers

    NASA Astrophysics Data System (ADS)

    Ehara, Yoshiyasu; Amemiya, Yusuke; Yamamoto, Toshiaki

    A generation and reduction of NOx on air-fed ozonizers using a ferroelectric packed bed reactor have been experimentally investigated. The reactors packed with CaTiO3, SrTiO3 and BaTiO3 pellets are examined for ozone generation. An ac voltage is applied to the reactor to generate partial discharge. Ozone concentration and the different nitrogen oxides at downstream of the packed bed reactor were measured with UV absorption ozone monitor and a Fourier transform infrared spectroscope respectively. The dielectric constant of packed ferroelectric pellets influences the discharge characteristic, ozone and NOx generations are varied by the dielectric constant value. Focusing on a discharge pulse current and maximum discharge magnitude, the ferroelectric packed bed plasma reactors have been evaluated on nitrogen oxide and ozone generated concentrations.

  13. 40 CFR 51.125 - Emissions reporting requirements for SIP revisions relating to budgets for SO2 and NOX emissions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... SIP revisions relating to budgets for SO2 and NOX emissions. 51.125 Section 51.125 Protection of... SIP revisions relating to budgets for SO2 and NOX emissions. (a) For its transport SIP revision under § 51.123 and/or 51.124, each State must submit to EPA SO2 and/or NOX emissions data as described...

  14. 40 CFR 51.125 - Emissions reporting requirements for SIP revisions relating to budgets for SO2 and NOX emissions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... SIP revisions relating to budgets for SO2 and NOX emissions. 51.125 Section 51.125 Protection of... SIP revisions relating to budgets for SO2 and NOX emissions. (a) For its transport SIP revision under § 51.123 and/or 51.124, each State must submit to EPA SO2 and/or NOX emissions data as described...

  15. Simulation of catalytic oxidation and selective catalytic NOx reduction in lean-exhaust hybrid vehicles

    SciTech Connect

    Gao, Zhiming; Daw, C Stuart; Chakravarthy, Veerathu K

    2012-01-01

    We utilize physically-based models for diesel exhaust catalytic oxidation and urea-based selective catalytic NOx reduction to study their impact on drive cycle performance of hypothetical light-duty diesel powered hybrid vehicles. The models have been implemented as highly flexible SIMULINK block modules that can be used to study multiple engine-aftertreatment system configurations. The parameters of the NOx reduction model have been adjusted to reflect the characteristics of Cu-zeolite catalysts, which are of widespread current interest. We demonstrate application of these models using the Powertrain System Analysis Toolkit (PSAT) software for vehicle simulations, along with a previously published methodology that accounts for emissions and temperature transients in the engine exhaust. Our results illustrate the potential impact of DOC and SCR interactions for lean hybrid electric and plug-in hybrid electric vehicles.

  16. Impact of Heavy Duty Vehicle Emissions Reductions on Global Climate

    SciTech Connect

    Calvin, Katherine V.; Thomson, Allison M.

    2010-08-01

    The impact of a specified set of emissions reductions from heavy duty vehicles on climate change is calculated using the MAGICC 5.3 climate model. The integrated impact of the following emissions changes are considered: CO2, CH4, N2O, VOC, NOx, and SO2. This brief summarizes the assumptions and methods used for this calculation.

  17. NOx emissions from Euro IV busses with SCR systems associated with urban, suburban and freeway driving patterns.

    PubMed

    Fu, Mingliang; Ge, Yunshan; Wang, Xin; Tan, Jianwei; Yu, Linxiao; Liang, Bin

    2013-05-01

    NOx and particulate matter (PM) emissions from heavy-duty diesel vehicles (HDVs) have become the most important sources of pollutants affecting urban air quality in China. In recent years, a series of emission control strategies and diesel engine polices have been introduced that require advanced emission control technology. China and Europe mostly have used Selective Catalytic Reduction (SCR) with urea to meet the Euro IV diesel engine emission standard. In this study, two Euro IV busses with SCR were tested by using potable emission measurement system (PEMS) to assess NOx emissions associated with urban, suburban and freeway driving patterns. The results indicated that with the SCR system, the urea injection time for the entire driving period increased with higher vehicle speed. For freeway driving, the urea injection time covered 71%-83% of the driving period; the NOx emission factors from freeway driving were lower than those associated with urban and suburban driving. Unfortunately, the NOx emission factors were 2.6-2.8-, 2.3-2.7- and 2.2-2.3-fold higher than the Euro IV standard limits for urban, suburban and freeway driving, respectively; NOx emission factors (in g/km and g/(kW·h)) from the original vehicles (without SCR) were higher than their corresponding vehicles with SCR for suburban and freeway driving. Compared with the IVE model results, the measured NOx emission factors were 1.60-1.16-, 1.77-1.27-, 2.49-2.44-fold higher than the NOx predicted by the IVE model for urban and suburban driving, respectively. Thus, an adjustment of emission factors is needed to improve the estimation of Euro IV vehicle emissions in China.

  18. On-Road Measurements of NO2 /NOx and NOx / CO Vehicle Emission Ratios in Colorado Summer Traffic

    NASA Astrophysics Data System (ADS)

    Wild, R. J.; Peischl, J.; Ryerson, T. B.; Neuman, J. A.; Dube, W. P.; Brown, S. S.

    2014-12-01

    Emissions of nitrogen oxides (NO and NO2) from vehicles are important precursors to ozone (O3) formation, and thus contribute to environmental and health issues. Both carbon dioxide (CO2) and carbon monoxide (CO) are large emissions from combustion, with the former a marker for total fuel consumption and the latter a commonly used combustion tracer. Thus, measurements of NOx to CO and CO2 emission ratios form an important part of characterizing total vehicle NOx emissions. Vehicle NOx emissions are primarily in the form of NO, although the NO2 content of these emissions may be changing as a result of control technology implementation, particularly for Diesel engines. Characterization of direct NO2 emission factors (i.e., NO2 to NOx ratio) is important because NO2 produces ozone upon its photolysis, while NO emission titrates ozone near sources. NO + O3 → NO2 + O2NO2 + hν (+ O2) → NO + O3Higher NO2 to NO emission ratios will likely result in higher ozone levels per unit NOx emitted. Higher NO2 emission ratios also lead to ozone production in closer proximity to the emission sources. There is a substantial lack of top-down measurements to assess emission inventories. Here we present an analysis of on-road measurements of vehicular emissions. We simultaneously measured NO, NO2 and O3 with a shared inlet at 20 pptv/s precision using a custom-built cavity ring-down measurement system in an instrumented van, together with high time resolution measurements of CO and CO2. Measurements were performed while driving throughout the Colorado Front Range urban area. We present a statistical analysis of vehicle plumes and their corresponding emissions ratios that can be used to constrain the direct emission ratio of NO2 in NOx, and NOx emission factors relative to CO and CO2.

  19. Quantification of NOx emissions from NO2 hotspots over China: A satellite perspective

    NASA Astrophysics Data System (ADS)

    Liu, Fei; Beirle, Steffen; Zhang, Qiang; Wagner, Thomas; He, Kebin

    2014-05-01

    China is the primary contributor of global anthropogenic NOx emissions, owing to its massive energy demand driven by strong economic growth. Most of the emissions are emitted by power plants or/and from urban areas, from which have been placed considerable emphasis on promoting emission reduction by Chinese government. Better knowledge of their emissions could help to assess the achieved emission reductions and provide perspectives as to the future effectiveness, which is also a valuable aid for taking regulatory steps. Thus we have developed an unit-based emission inventory of China's coal-fired power plants with high spatial and temporal resolution for the period 1990-2010 in our previous work (Liu et al., in preparation), but developing an emission inventory for each city at the same resolution and accuracy is much more challenging. Strong power plants and large cities can be identified as NO2 "hotspots" using satellite-based instruments. It has been demonstrated in previous studies (Beirle et al., Science, 2011) that OMI products can be applied for the determination of megacity NOx emissions and their lifetime by analyzing the downwind decay of the NO2 plume. In addition, from the analysis of the OMI time-series, the construction of new, large power plants in China can clearly be identified (Zhang et al, GRL, 2009). We are working on determining Chinese hotspots emissions and lifetimes of NOx simultaneously from the observed downwind plume evolution and ECMWF wind fields using the latest OMI product (DOMINO V2.0). However, the method applied to isolated megacities like Riyadh needs to be modified in order to take interferences of several strong NOx sources within small distances into account.We will present and discuss different approaches to deal with this challenge. The derived power plant emission will be compared to the bottom-up unit-based emission inventory. The found relation between bottom-up and top-down emissions will be used for the evaluation of top

  20. Modeling the effects of VOC/NOx emissions on ozone synthesis in the cascadia airshed of the Pacific Northwest.

    PubMed

    Barna, M; Lamb, B; Westberg, H

    2001-07-01

    A modeling system consisting of MM5, Calmet, and Calgrid was used to investigate the sensitivity of anthropogenic volatile organic compound (VOC) and oxides of nitrogen (NOx) reductions on ozone formation within the Cascadia airshed of the Pacific Northwest. An ozone episode that occurred on July 11-14, 1996, was evaluated. During this event, high ozone levels were recorded at monitors downwind of Seattle, WA, and Portland, OR, with one monitor exceeding the 1 hr/120 ppb National Ambient Air Quality Standard (at 148 ppb), and six monitors above the proposed 8 hr/80 ppb standard (at 82-130 ppb). For this particular case, significant emissions reductions, between 25 and 75%, would be required to decrease peak ozone concentrations to desired levels. Reductions in VOC emissions alone, or a combination of reduced VOC and NOx emissions, were generally found to be most effective; reducing NOx emissions alone resulted in increased ozone in the Seattle area. When only VOC emissions were curtailed, ozone reductions occurred in the immediate vicinity of densely populated areas, while NOx reductions resulted in more widespread ozone reductions. PMID:15658221

  1. 40 CFR 75.12 - Specific provisions for monitoring NOX emission rate.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 17 2014-07-01 2014-07-01 false Specific provisions for monitoring NOX... provisions for monitoring NOX emission rate. (a) Coal-fired units, gas-fired nonpeaking units or oil-fired... for a NOX continuous emission monitoring system (CEMS) for each affected coal-fired unit,...

  2. 40 CFR 75.12 - Specific provisions for monitoring NOX emission rate.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 17 2013-07-01 2013-07-01 false Specific provisions for monitoring NOX... provisions for monitoring NOX emission rate. (a) Coal-fired units, gas-fired nonpeaking units or oil-fired... for a NOX continuous emission monitoring system (CEMS) for each affected coal-fired unit,...

  3. 40 CFR 75.12 - Specific provisions for monitoring NOX emission rate.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 17 2012-07-01 2012-07-01 false Specific provisions for monitoring NOX... provisions for monitoring NOX emission rate. (a) Coal-fired units, gas-fired nonpeaking units or oil-fired... for a NOX continuous emission monitoring system (CEMS) for each affected coal-fired unit,...

  4. 40 CFR 60.4380 - How are excess emissions and monitor downtime defined for NOX?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... downtime defined for NOX? 60.4380 Section 60.4380 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... downtime defined for NOX? For the purpose of reports required under § 60.7(c), periods of excess emissions... NOX control will also be considered an excess emission. (2) A period of monitor downtime is any...

  5. 40 CFR 60.4320 - What emission limits must I meet for nitrogen oxides (NOX)?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 7 2014-07-01 2014-07-01 false What emission limits must I meet for nitrogen oxides (NOX)? 60.4320 Section 60.4320 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... nitrogen oxides (NOX)? (a) You must meet the emission limits for NOX specified in Table 1 to this...

  6. 40 CFR 60.4320 - What emission limits must I meet for nitrogen oxides (NOX)?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 7 2013-07-01 2013-07-01 false What emission limits must I meet for nitrogen oxides (NOX)? 60.4320 Section 60.4320 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... nitrogen oxides (NOX)? (a) You must meet the emission limits for NOX specified in Table 1 to this...

  7. 40 CFR 60.4320 - What emission limits must I meet for nitrogen oxides (NOX)?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 7 2012-07-01 2012-07-01 false What emission limits must I meet for nitrogen oxides (NOX)? 60.4320 Section 60.4320 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... nitrogen oxides (NOX)? (a) You must meet the emission limits for NOX specified in Table 1 to this...

  8. 40 CFR 60.4320 - What emission limits must I meet for nitrogen oxides (NOX)?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 6 2011-07-01 2011-07-01 false What emission limits must I meet for nitrogen oxides (NOX)? 60.4320 Section 60.4320 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... nitrogen oxides (NOX)? (a) You must meet the emission limits for NOX specified in Table 1 to this...

  9. 40 CFR 60.4320 - What emission limits must I meet for nitrogen oxides (NOX)?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false What emission limits must I meet for nitrogen oxides (NOX)? 60.4320 Section 60.4320 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... nitrogen oxides (NOX)? (a) You must meet the emission limits for NOX specified in Table 1 to this...

  10. CONTROLLING NOX EMISSION FROM INDUSTRIAL SOURCES

    EPA Science Inventory

    A number of regulatory actions focused on reducing NOx emissions from stationary combustion sources have been taken in the United States in the last decade. These actions include the Acid Rain NOx regulations, the Ozone Transport Commission's NOx ...

  11. Optimal deployment of emissions reduction technologies for construction equipment.

    PubMed

    Bari, Muhammad Ehsanul; Zietsman, Josias; Quadrifoglio, Luca; Farzaneh, Mohamadreza

    2011-06-01

    The objective of this research was to develop a multiobjective optimization model to deploy emissions reduction technologies for nonroad construction equipment to reduce emissions in a cost-effective and optimal manner. Given a fleet of construction equipment emitting different pollutants in the nonattainment (NA) and near -nonattainment (NNA) counties of a state and a set of emissions reduction technologies available for installation on equipment to control pollution/emissions, the model assists in determining the mix of technologies to be deployed so that maximum emissions reduction and fuel savings are achieved within a given budget. Three technologies considered for emissions reduction were designated as X, Y, and Z to keep the model formulation general so that it can be applied for any other set of technologies. Two alternative methods of deploying these technologies on a fleet of equipment were investigated with the methods differing in the technology deployment preference in the NA and NNA counties. The model having a weighted objective function containing emissions reduction benefits and fuel-saving benefits was programmed with C++ and ILOG-CPLEX. For demonstration purposes, the model was applied for a selected construction equipment fleet owned by the Texas Department of Transportation, located in NA and NNA counties of Texas, assuming the three emissions reduction technologies X, Y, and Z to represent, respectively, hydrogen enrichment, selective catalytic reduction, and fuel additive technologies. Model solutions were obtained for varying budget amounts to test the sensitivity of emissions reductions and fuel-savings benefits with increasing the budget. Different mixes of technologies producing maximum oxides of nitrogen (NO(x)) reductions and total combined benefits (emissions reductions plus fuel savings) were indicated at different budget ranges. The initial steep portion of the plots for NO(x) reductions and total combined benefits against budgets

  12. Lean NOx reduction over Ag/alumina catalysts via ethanol-SCR using ethanol/gasoline blends

    DOE PAGESBeta

    Gunnarsson, Fredrik; Pihl, Josh A.; Toops, Todd J.; Skoglundh, Magnus; Härelind, Hanna

    2016-09-04

    This paper focuses on the activity for lean NOx reduction over sol-gel synthesized silver alumina (Ag/Al2O3) catalysts, with and without platinum doping, using ethanol (EtOH), EtOH/C3H6 and EtOH/gasoline blends as reducing agents. The effect of ethanol concentration, both by varying the hydrocarbon-to-NOx ratio and by alternating the gasoline concentration in the EtOH/gasoline mixture, is investigated. High activity for NOx reduction is demonstrated for powder catalysts for EtOH and EtOH/C3H6 as well as for monolith coated catalysts (EtOH and EtOH/gasoline). The results show that pure Ag/Al2O3 catalysts display higher NOx reduction and lower light-off temperature as compared to the platinum dopedmore » samples. The 4 wt.% Ag/Al2O3 catalyst displays 100% reduction in the range 340–425 °C, with up to 37% selectivity towards NH3. These results are also supported by DRIFTS (Diffuse reflection infrared Fourier transform spectroscopy) experiments. Finally, the high ammonia formation could, in combination with an NH3-SCR catalyst, be utilized to construct a NOx reduction system with lower fuel penalty cf. stand alone HC-SCR. In addition, it would result in an overall decrease in CO2 emissions.« less

  13. 40 CFR 1037.102 - Exhaust emission standards for NOX, HC, PM, and CO.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... (CONTINUED) AIR POLLUTION CONTROLS CONTROL OF EMISSIONS FROM NEW HEAVY-DUTY MOTOR VEHICLES Emission Standards and Related Requirements § 1037.102 Exhaust emission standards for NOX, HC, PM, and CO. See 40 CFR... 40 Protection of Environment 33 2014-07-01 2014-07-01 false Exhaust emission standards for NOX,...

  14. 40 CFR 1037.102 - Exhaust emission standards for NOX, HC, PM, and CO.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... (CONTINUED) AIR POLLUTION CONTROLS CONTROL OF EMISSIONS FROM NEW HEAVY-DUTY MOTOR VEHICLES Emission Standards and Related Requirements § 1037.102 Exhaust emission standards for NOX, HC, PM, and CO. See 40 CFR... 40 Protection of Environment 34 2012-07-01 2012-07-01 false Exhaust emission standards for NOX,...

  15. 40 CFR 1037.102 - Exhaust emission standards for NOX, HC, PM, and CO.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... (CONTINUED) AIR POLLUTION CONTROLS CONTROL OF EMISSIONS FROM NEW HEAVY-DUTY MOTOR VEHICLES Emission Standards and Related Requirements § 1037.102 Exhaust emission standards for NOX, HC, PM, and CO. See 40 CFR... 40 Protection of Environment 34 2013-07-01 2013-07-01 false Exhaust emission standards for NOX,...

  16. Multifunctional Low Pressure Turbine for Core Noise Reduction, Improved Efficiency, and NOx Reduction

    NASA Technical Reports Server (NTRS)

    Miller, Chris; Shyam, Vikram; Rigby, David; Acosta, Waldo

    2013-01-01

    Determining the feasibility of the induced synthetic jet is key, and is still TBD. center dot Available LPT vane volume is sufficient for tens of resonators per span-wise hole spacing, so physically feasible. center dot Determination of acoustic attenuation requires accurate model of vane, resonator locations, flow field and incident waves. (TBD) center dot Determination of NOx reduction is also TBD.

  17. Overall evaluation of combustion and NO(x) emissions for a down-fired 600 MW(e) supercritical boiler with multiple injection and multiple staging.

    PubMed

    Kuang, Min; Li, Zhengqi; Liu, Chunlong; Zhu, Qunyi

    2013-05-01

    To achieve significant reductions in NOx emissions and to eliminate strongly asymmetric combustion found in down-fired boilers, a deep-air-staging combustion technology was trialed in a down-fired 600 MWe supercritical utility boiler. By performing industrial-sized measurements taken of gas temperatures and species concentrations in the near wing-wall region, carbon in fly ash and NOx emissions at various settings, effects of overfire air (OFA) and staged-air damper openings on combustion characteristics, and NOx emissions within the furnace were experimentally determined. With increasing the OFA damper opening, both fluctuations in NOx emissions and carbon in fly ash were initially slightly over OFA damper openings of 0-40% but then lengthened dramatically in openings of 40-70% (i.e., NOx emissions reduced sharply accompanied by an apparent increase in carbon in fly ash). Decreasing the staged-air declination angle clearly increased the combustible loss but slightly influenced NOx emissions. In comparison with OFA, the staged-air influence on combustion and NOx emissions was clearly weaker. Only at a high OFA damper opening of 50%, the staged-air effect was relatively clear, i.e., enlarging the staged-air damper opening decreased carbon in fly ash and slightly raised NOx emissions. By sharply opening the OFA damper to deepen the air-staging conditions, although NOx emissions could finally reduce to 503 mg/m(3) at 6% O2 (i.e., an ultralow NOx level for down-fired furnaces), carbon in fly ash jumped sharply to 15.10%. For economical and environment-friendly boiler operations, an optimal damper opening combination (i.e., 60%, 50%, and 50% for secondary air, staged-air, and OFA damper openings, respectively) was recommended for the furnace, at which carbon in fly ash and NOx emissions attained levels of about 10% and 850 mg/m(3) at 6% O2, respectively.

  18. Experimental investigation on NOx emission characteristics of a new solid fuel made from sewage sludge mixed with coal in combustion.

    PubMed

    Zhai, Yunbo; Zhu, Lu; Chen, Hongmei; Xu, Bibo; Li, Caiting; Zeng, Guangming

    2015-02-01

    In this article, a new briquette fuel (SC), which was produced by the mixture of coal fines (25.9%), sewage sludge (60.6%), lignin (4.5%), tannic acid (4.5%) and elemental silicon (4.5%), was provided. Then, in a high temperature electric resistance tubular furnace, the total emissions of NO2 and NO, effects of combustion temperature, air flow rate and heating rate on NOx (NO, NO2) emissions of SC were studied during the combustion of SC; furthermore, effects of additives on hardness were also analysed, and the X-ray photoelectron spectroscopy was applied to investigate the reduced NOx emission mechanism. The research results showed that, compared with the characteristics of briquette fuel (SC0) produced only by the mixture of coal and sewage sludge (the ratio of coal to sewage sludge was the same as that of SC), the Meyer hardness of SC was 12.6% higher than that of SC0 and the emissions of NOx were 27.83% less than that of SC0 under the same combustion conditions. The NOx emissions of SC decreased with the adding of heating rate and increased with the rise of air flow rate. When the temperature was below 1000 °C, the emissions of NOx increased with the elevated temperature, however, further temperature extension will result in a decreasing in emissions of NOx. Furthermore, the X-ray photoelectron spectroscopy results proposed that the possible mechanism for the reduction of NOx emissions was nitrogen and silicon in SC to form the compounds of silicon and nitrogen at high temperatures.

  19. Experimental Assessment of NOx Emissions from 73 Euro 6 Diesel Passenger Cars.

    PubMed

    Yang, Liuhanzi; Franco, Vicente; Mock, Peter; Kolke, Reinhard; Zhang, Shaojun; Wu, Ye; German, John

    2015-12-15

    Controlling nitrogen oxides (NOx) emissions from diesel passenger cars during real-world driving is one of the major technical challenges facing diesel auto manufacturers. Three main technologies are available for this purpose: exhaust gas recirculation (EGR), lean-burn NOx traps (LNT), and selective catalytic reduction (SCR). Seventy-three Euro 6 diesel passenger cars (8 EGR only, 40 LNT, and 25 SCR) were tested on a chassis dynamometer over both the European type-approval cycle (NEDC, cold engine start) and the more realistic Worldwide harmonized light-duty test cycle (WLTC version 2.0, hot start) between 2012 and 2015. Most vehicles met the legislative limit of 0.08 g/km of NOx over NEDC (average emission factors by technology: EGR-only 0.07 g/km, LNT 0.04 g/km, and SCR 0.05 g/km), but the average emission factors rose dramatically over WLTC (EGR-only 0.17 g/km, LNT 0.21 g/km, and SCR 0.13 g/km). Five LNT-equipped vehicles exhibited very poor performance over the WLTC, emitting 7-15 times the regulated limit. These results illustrate how diesel NOx emissions are not properly controlled under the current, NEDC-based homologation framework. The upcoming real-driving emissions (RDE) regulation, which mandates an additional on-road emissions test for EU type approvals, could be a step in the right direction to address this problem. PMID:26580818

  20. 40 CFR 75.19 - Optional SO2, NOX, and CO2 emissions calculation for low mass emissions (LME) units.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... emission test data that is representative of operation at normal load or historical data from a CEMS... historical emission test data that is representative of operation at normal load. The NOX emission limit... rate by conducting a four load NOX emission rate test procedure as specified in section 2.1 of...

  1. LOW NOx EMISSIONS IN A FUEL FLEXIBLE GAS TURBINE

    SciTech Connect

    Raymond Drnevich; James Meagher; Vasilis Papavassiliou; Troy Raybold; Peter Stuttaford; Leonard Switzer; Lee Rosen

    2004-08-01

    In alignment with Vision 21 goals, a study is presented here on the technical and economic potential for developing a gas turbine combustor that is capable of generating less that 2 ppm NOx emissions, firing on either coal synthesis gas or natural gas, and being implemented on new and existing systems. The proposed solution involves controlling the quantity of H2 contained in the fuel. The presence of H2 leads to increased flame stability such that the combustor can be operated at lower temperatures and produce less thermal NOx. Coal gas composition would be modified using a water gas shift converter, and natural gas units would implement a catalytic partial oxidation (CPOX) reactor to convert part of the natural gas feed to a syngas before fed back into the combustor. While both systems demonstrated technical merit, the economics involved in implementing such a system are marginal at best. Therefore, Praxair has decided not to pursue the technology any further at this time.

  2. Influence of population density and temporal variations in emissions on the air duality benefits of NOx emission trading.

    PubMed

    Nobel, Carolyn E; McDonald-Buller, Elena C; Kimura, Yosuke; Lumbley, Katherine E; Allen, David T

    2002-08-15

    Ozone formation is a complex function of local hydrocarbon and nitrogen oxide emissions. Therefore, trading of NOx emissions among geographically distributed facilities can lead to more or less ozone formation than across-the-board reductions. Monte Carlo simulations of trading scenarios involving 51 large NOx point sources in eastern Texas were used in a previous study by the authors to assess the effects of trading on air quality benefits, as measured by changes in ozone concentrations. The results indicated that 12% of trading scenarios would lead to greater than a 25% variation from conventional across-the-board reductions when air quality benefits are based only on changes in ozone concentration. The current study found that when benefits are based on a metric related to population exposure to ozone, two-thirds of the trading scenarios lead to changes in air quality benefits of approximately 25%. Variability in air quality benefits is not as strongly dependent on the temporal distribution of NOx emissions.

  3. Latest results on reducing NOx emissions at American Electric Power's coal fired utility boilers with DB Riley's CCV burner technologies

    SciTech Connect

    Patel, R.; Penterson, C.; Weinshiemer, J.

    2000-07-01

    American Electric Power Service Corporation (AEP) and DB Riley, Inc., under an alliance arrangement, have retrofitted eight coal fired utility boilers with DB Riley's Controlled Combustion Venturi (CCV{reg_sign}) burners for reducing NOx emissions prior to SCR and/or SNCR installations on some of these units. These units all burn eastern bituminous coal and range in size from 260 to 1,300 MWn. The larger utility boilers are equipped with cell fired burners while the smaller units utilize more traditional single circular coal burners. The low NOx CCV{reg_sign} burner technology installed consisted of a variety of different designs including CCV{reg_sign} single register and CCV{reg_sign} cell burners. All burners were designed to be a ``plug into the existing waterwall openings'' type to preclude pressure part modifications. The most unique retrofit involved the installation of low NOx burners on all four-furnace walls of a 450 MWn utility boiler. Pre-retrofit baseline NOx levels on these eight (8) utility boilers ranged from 0.9 to 1.6 lb/mmbtu while post-retrofit NOx emission levels ranged from 0.42 to 0.70 lb/mmbtu. This represents about 50--60% reduction in NOx from uncontrolled levels using the burners only technology. This paper describes the latest results from this major low NOx burner retrofit project.

  4. Agricultural Bio-Fueled Generation of Electricity and Development of Durable and Efficent NOx Reduction

    SciTech Connect

    Boyd, Rodney

    2007-08-08

    The objective of this project was to define the scope and cost of a technology research and development program that will demonstrate the feasibility of using an off-the-shelf, unmodified, large bore diesel powered generator in a grid-connected application, utilizing various blends of BioDiesel as fuel. Furthermore, the objective of project was to develop an emissions control device that uses a catalytic process and BioDiesel (without the presence of Ammonia or Urea)to reduce NOx and other pollutants present in a reciprocating engine exhaust stream with the goal of redefining the highest emission reduction efficiencies possible for a diesel reciprocating generator. Process: Caterpillar Power Generation adapted an off-the-shelf Diesel Generator to run on BioDiesel and various Petroleum Diesel/BioDiesel blends. EmeraChem developed and installed an exhaust gas cleanup system to reduce NOx, SOx, volatile organics, and particulates. The system design and function was optimized for emissions reduction with results in the 90-95% range;

  5. High NO2/NOx emissions downstream of the catalytic diesel particulate filter: An influencing factor study.

    PubMed

    He, Chao; Li, Jiaqiang; Ma, Zhilei; Tan, Jianwei; Zhao, Longqing

    2015-09-01

    Diesel vehicles are responsible for most of the traffic-related nitrogen oxide (NOx) emissions, including nitric oxide (NO) and nitrogen dioxide (NO2). The use of after-treatment devices increases the risk of high NO2/NOx emissions from diesel engines. In order to investigate the factors influencing NO2/NOx emissions, an emission experiment was carried out on a high pressure common-rail, turbocharged diesel engine with a catalytic diesel particulate filter (CDPF). NO2 was measured by a non-dispersive ultraviolet analyzer with raw exhaust sampling. The experimental results show that the NO2/NOx ratios downstream of the CDPF range around 20%-83%, which are significantly higher than those upstream of the CDPF. The exhaust temperature is a decisive factor influencing the NO2/NOx emissions. The maximum NO2/NOx emission appears at the exhaust temperature of 350°C. The space velocity, engine-out PM/NOx ratio (mass based) and CO conversion ratio are secondary factors. At a constant exhaust temperature, the NO2/NOx emissions decreased with increasing space velocity and engine-out PM/NOx ratio. When the CO conversion ratios range from 80% to 90%, the NO2/NOx emissions remain at a high level.

  6. High NO2/NOx emissions downstream of the catalytic diesel particulate filter: An influencing factor study.

    PubMed

    He, Chao; Li, Jiaqiang; Ma, Zhilei; Tan, Jianwei; Zhao, Longqing

    2015-09-01

    Diesel vehicles are responsible for most of the traffic-related nitrogen oxide (NOx) emissions, including nitric oxide (NO) and nitrogen dioxide (NO2). The use of after-treatment devices increases the risk of high NO2/NOx emissions from diesel engines. In order to investigate the factors influencing NO2/NOx emissions, an emission experiment was carried out on a high pressure common-rail, turbocharged diesel engine with a catalytic diesel particulate filter (CDPF). NO2 was measured by a non-dispersive ultraviolet analyzer with raw exhaust sampling. The experimental results show that the NO2/NOx ratios downstream of the CDPF range around 20%-83%, which are significantly higher than those upstream of the CDPF. The exhaust temperature is a decisive factor influencing the NO2/NOx emissions. The maximum NO2/NOx emission appears at the exhaust temperature of 350°C. The space velocity, engine-out PM/NOx ratio (mass based) and CO conversion ratio are secondary factors. At a constant exhaust temperature, the NO2/NOx emissions decreased with increasing space velocity and engine-out PM/NOx ratio. When the CO conversion ratios range from 80% to 90%, the NO2/NOx emissions remain at a high level. PMID:26354692

  7. 40 CFR 96.354 - Compliance with CAIR NOX emissions limitation.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... IMPLEMENTATION PLANS CAIR NOX Ozone Season Allowance Tracking System § 96.354 Compliance with CAIR NOX emissions... under paragraph (d)(1) of this section shall not affect the liability of the owners and operators of the... Administrator may review and conduct independent audits concerning any submission under the CAIR NOX...

  8. CONTROL OF NOX EMISSIONS FROM U.S. COAL-FIRED ELECTRIC UTILITY BOILERS

    EPA Science Inventory

    The paper discusses the control of nitrogen oxide (NOx) emissions from U.S. coal-fired electric utility boilers. (NOTE: In general, NOx control technologies are categorized as being either primary or secondary control technologies. Primary technologies reduce the amount of NOx pr...

  9. Application of hybrid coal reburning/SNCR processes for NOx reduction in a coal-fired boiler

    SciTech Connect

    Yang, W.J.; Zhou, Z.J.; Zhou, J.H.; Hongkun, L.V.; Liu, J.Z.; Cen, K.F.

    2009-07-01

    Boilers in Beijing Thermal Power Plant of Zhongdian Guohua Co. in China are coal-fired with natural circulation and tangential fired method, and the economical continuous rate is 410 ton per hour of steam. Hybrid coal reburning/SNCR technology was applied and it successfully reduced NOx to about 170 mg/Nm{sup 3} from about 540 mg/Nm{sup 3}, meanwhile ammonia slip was lower than 10 ppm at 450-210 t/h load and the total reduction efficiency was about 70%. Normal fineness pulverized coal from the bin was chosen as the reburning fuel and the nozzles of the upper primary air were retrofitted to be used as the reburning fuel nozzles. The reducing agent of SNCR was an urea solution, and it was injected by the four layer injectors after online dilution. At 410 t/h load, NOx emission was about 300 mg/Nm{sup 3} when the ratio of reburning fuel to the total fuel was 25.9%-33.4%. Controlling the oxygen content of the gas in the reversal chamber to less than 3.4% resulted in not only low NOx emission but also high combustion efficiency. Ammonia slip distribution in the down gas pass was uneven and ammonia slip was higher in the front of the down gas pass than in the rear of the down gas pass. NSR and NOx reduction were proportional to each other and usually resulted in more ammonia slip with reduction in NOx. About 100 mg/Nm{sup 3} NOx emission could be achieved with about 40 ppm NH{sub 3} slip at 300-450 t/h, and ammonia slip from the SNCR reactions could be used as reducing agent of SCR, which was favorable for the future SCR retrofit.

  10. Greenidge multi-pollutant project achieves emissions reduction goals

    SciTech Connect

    2008-07-01

    Performance testing at the Greenridge Multi-Pollutant Project has met or exceeded project goals, indicating that deep emission reduciton sin small, difficult-to-retrofit power plants can be achieved. The technology fitted at the 107 MWe AES Greenridge Unit 4 includes a hybrid selective non-catalytic reduction/selective catalytic reduction system for NOx control (NOxOUT CASCADE) and a Turbosorp circulating fluidized bed dry scrubber system for SO{sub 2}, mercury, SO{sub 3} HC and Hf control. 2 figs.

  11. Advances in potassium catalyzed NOx reduction by carbon materials: An overview

    SciTech Connect

    Bueno-Lopez, A.; Garcia-Garcia, A.; Illan-Gomez, M.J.; Linares-Solano, A.; de Lecea, C.S.M.

    2007-06-15

    The research work conducted in our group concerning the study of the potassium-catalyzed NOx reduction by carbon materials is presented. The importance of the different variables affecting the NOx-carbon reactions is discussed, e.g. carbon porosity, coal rank, potassium loading, influence of the binder used, and effect of the gas composition. The catalyst loading is the main feature affecting the selectivity for NOx reduction against O{sub 2} combustion. The NOx reduction without important combustion in O{sub 2} occurs between 350 and 475{sup o}C in the presence of the catalyst. The presence of H{sub 2}O in the gas mixture enhances NOx reduction at low carbon conversions, but as the reaction proceeds, it decreases as the selectivity does. The presence of CO{sub 2} diminishes the activity and selectivity of the catalyst. SO{sub 2} completely inhibits the catalytic activity of potassium due to sulfate formation.

  12. Development of a Comprehensive Community Nitrogen Oxide Emissions Reduction Toolkit (CCNERT)

    NASA Astrophysics Data System (ADS)

    Sung, Yong Hoon

    The main objective of this study is to research and develop a simplified tool to estimate energy use in a community and its associated effects on air pollution. This tool is intended to predict the impacts of selected energy conservation options and efficiency programs on emission reduction. It is intended to help local government and their residents understand and manage information collection and the procedures to be used. This study presents a broad overview of the community-wide energy use and NOx emissions inventory process. It also presents various simplified procedures to estimate each sector's energy use. In an effort to better understand community-wide energy use and its associated NOx emissions, the City of College Station, Texas, was selected as a case study community for this research. While one community might successfully reduce the production of NOx emissions by adopting electricity efficiency programs in its buildings, another community might be equally successful by changing the mix of fuel sources used to generate electricity, which is consumed by the community. In yet a third community low NOx automobiles may be mandated. Unfortunately, the impact and cost of one strategy over another changes over time as major sources of pollution are reduced. Therefore, this research proposes to help community planners answer these questions and to assist local communities with their NOx emission reduction plans by developing a Comprehensive Community NOx Emissions Reduction Toolkit (CCNERT). The proposed simplified tool could have a substantial impact on reducing NOx emission by providing decision-makers with a preliminary understanding about the impacts of various energy efficiency programs on emissions reductions. To help decision makers, this study has addressed these issues by providing a general framework for examining how a community's non-renewable energy use leads to NOx emissions, by quantifying each end-user's energy usage and its associated NOx

  13. 40 CFR 75.72 - Determination of NOX mass emissions for common stack and multiple stack configurations.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 17 2014-07-01 2014-07-01 false Determination of NOX mass emissions... ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTINUOUS EMISSION MONITORING NOX Mass Emissions Provisions § 75.72 Determination of NOX mass emissions for common stack and multiple...

  14. 40 CFR 75.72 - Determination of NOX mass emissions for common stack and multiple stack configurations.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 17 2013-07-01 2013-07-01 false Determination of NOX mass emissions... ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTINUOUS EMISSION MONITORING NOX Mass Emissions Provisions § 75.72 Determination of NOX mass emissions for common stack and multiple...

  15. 40 CFR 75.72 - Determination of NOX mass emissions for common stack and multiple stack configurations.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 16 2011-07-01 2011-07-01 false Determination of NOX mass emissions... ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTINUOUS EMISSION MONITORING NOX Mass Emissions Provisions § 75.72 Determination of NOX mass emissions for common stack and multiple...

  16. SLCP co-control approach in East Asia: Tropospheric ozone reduction strategy by simultaneous reduction of NOx/NMVOC and methane

    NASA Astrophysics Data System (ADS)

    Akimoto, Hajime; Kurokawa, Jun`ichi; Sudo, Kengo; Nagashima, Tatsuya; Takemura, Toshihiko; Klimont, Zbigniew; Amann, Markus; Suzuki, Katsunori

    2015-12-01

    The emissions of NOx and CO2 in East Asia (Northeast and Southeast Asia) contribute more than 30% of the global total since 2008, and consequently the control of air pollutants and CO2 alleviating regional air pollution and global climate change is of great concern of not only in this region but also worldwide. In order to arrive at a rational view of the short-lived climate pollutants (SLCPs) co-control approach in East Asia, the effectiveness of the reduction of NOx/NMVOC and CH4 emissions for the reduction of tropospheric O3 has been evaluated by individual and simultaneous 50%-reduction of the emissions in Northeast Asia (NEA) using both a global chemical climate model (CHASER/SPRINTARS-MIROC), and a regional chemical transport model (WRF-CMAQ). The simultaneous reduction of NOx/NMVOC and CH4 emissions was found to reduce the regional concentration of surface O3 in NEA, and globally averaged net radiative forcing most effectively. Global mean RF and regional air quality change were also evaluated for the climate stabilization scenario ("450-ppm"), and climate stabilization with additional air pollution mitigation strengthened scenario ("450-ppm-cntr") developed in IIASA with the aid of GAINS model. In the 450 ppm-cntr scenario, emissions of NOx NMVOC, BC and OC were further reduced respectively, for East Asia from the emissions in 450 ppm. The improvement of air quality as well as the mitigation of climate change would grant to the basis of the SLCP co-control approach in East Asia.

  17. Spatio-temporal variability in isotopic signatures of atmospheric NOx emissions from vehicles

    NASA Astrophysics Data System (ADS)

    Miller, D. J.; Wojtal, P.; O'Connor, M.; Clark, S.; Hastings, M. G.

    2015-12-01

    Atmospheric nitrogen oxides (NOx = NO + NO2) play key roles in atmospheric chemistry and radiative forcing. Their oxidation products, nitric acid or nitrate, have significant contributions to nitrogen (N) deposition, with implications for ecosystem health. On-road vehicle NOx sources currently dominate U.S. anthropogenic emission budgets, yet vehicle NOx emissions contributions to local and regional N deposition patterns are highly uncertain. NOx isotopic signatures offer a potentially valuable observational tool to trace source contributions to N deposition. We characterize the spatio-temporal variability of vehicle NOx emission isotopic signatures with a field and laboratory-verified technique for actively capturing NOx in solution to quantify the nitrogen isotopic composition (δ15N-NOx) to within ±1.5‰ (1σ) precision. We present a novel combination of on-road mobile and stationary urban δ15N-NOx measurements at minutes to hourly resolution along with NOx and CO2 concentration measurements. We evaluate spatial gradients of δ15N-NOx on U.S. Northeast and Midwest highways, including six urban metropolitan areas and rural interstate highways during summer and autumn. We also assess on-road diurnal δ15N-NOx variations over ~800 km driving distance in Providence, RI by targeting the upwind footprint of urban background measurements to distinguish background and source NOx. We observe on-road δ15N-NOx signatures range from -3 to -10‰ under different traffic conditions in the U.S. Northeast and Midwest. On-road δ15N-NOx daytime variations from -3 to -6‰ agree well with simultaneous urban background sampling in Providence, RI, suggesting that vehicles dominate NOx emissions in this region. We use these datasets to estimate the range of representative δ15N-NOx source signatures for U.S. vehicle fleet-integrated emission plumes. Our novel approach suggests that previously reported isotopic signatures for vehicle NOx are not necessarily representative. These

  18. Two-stage Catalytic Reduction of NOx with Hydrocarbons

    SciTech Connect

    Umit S. Ozkan; Erik M. Holmgreen; Matthew M. Yung; Jonathan Halter; Joel Hiltner

    2005-12-21

    A two-stage system for the catalytic reduction of NO from lean-burn natural gas reciprocating engine exhaust is investigated. Each of the two stages uses a distinct catalyst. The first stage is oxidation of NO to NO{sub 2} and the second stage is reduction of NO{sub 2} to N{sub 2} with a hydrocarbon. The central idea is that since NO{sub 2} is a more easily reduced species than NO, it should be better able to compete with oxygen for the combustion reaction of hydrocarbon, which is a challenge in lean conditions. Early work focused on demonstrating that the N{sub 2} yield obtained when NO{sub 2} was reduced was greater than when NO was reduced. NO{sub 2} reduction catalysts were designed and silver supported on alumina (Ag/Al{sub 2}O{sub 3}) was found to be quite active, able to achieve 95% N{sub 2} yield in 10% O{sub 2} using propane as the reducing agent. The design of a catalyst for NO oxidation was also investigated, and a Co/TiO{sub 2} catalyst prepared by sol-gel was shown to have high activity for the reaction, able to reach equilibrium conversion of 80% at 300 C at GHSV of 50,000h{sup -1}. After it was shown that NO{sub 2} could be more easily reduced to N{sub 2} than NO, the focus shifted on developing a catalyst that could use methane as the reducing agent. The Ag/Al{sub 2}O{sub 3} catalyst was tested and found to be inactive for NOx reduction with methane. Through iterative catalyst design, a palladium-based catalyst on a sulfated-zirconia support (Pd/SZ) was synthesized and shown to be able to selectively reduce NO{sub 2} in lean conditions using methane. Development of catalysts for the oxidation reaction also continued and higher activity, as well as stability in 10% water, was observed on a Co/ZrO{sub 2} catalyst, which reached equilibrium conversion of 94% at 250 C at the same GHSV. The Co/ZrO{sub 2} catalyst was also found to be extremely active for oxidation of CO, ethane, and propane, which could potential eliminate the need for any separate

  19. Alkali- and Sulfur-Resistant Tungsten-Based Catalysts for NOx Emissions Control.

    PubMed

    Huang, Zhiwei; Li, Hao; Gao, Jiayi; Gu, Xiao; Zheng, Li; Hu, Pingping; Xin, Ying; Chen, Junxiao; Chen, Yaxin; Zhang, Zhaoliang; Chen, Jianmin; Tang, Xingfu

    2015-12-15

    The development of catalysts with simultaneous resistance to alkalis and sulfur poisoning is of great importance for efficiently controlling NOx emissions using the selective catalytic reduction of NOx with NH3 (SCR), because the conventional V2O5/WO3-TiO2 catalysts often suffer severe deactivation by alkalis. Here, we support V2O5 on a hexagonal WO3 (HWO) to develop a V2O5/HWO catalyst, which has exceptional resistance to alkali and sulfur poisoning in the SCR reactions. A 350 μmol g(-1) K(+) loading and the presence of 1,300 mg m(-3) SO2 do not almost influence the SCR activity of the V2O5/HWO catalyst, and under the same conditions, the conventional V2O5/WO3-TiO2 catalysts completely lost the SCR activity within 4 h. The strong resistance to alkali and sulfur poisoning of the V2O5/HWO catalysts mainly originates from the hexagonal structure of the HWO. The HWO allows the V2O5 to be highly dispersed on the external surfaces for catalyzing the SCR reactions and has the relatively smooth surfaces and the size-suitable tunnels specifically for alkalis' diffusion and trapping. This work provides a useful strategy to develop SCR catalysts with exceptional resistance to alkali and sulfur poisoning for controlling NOx emissions from the stationary source and the mobile source.

  20. Novel Mn-Ce-Ti mixed-oxide catalyst for the selective catalytic reduction of NOx with NH₃.

    PubMed

    Liu, Zhiming; Zhu, Junzhi; Li, Junhua; Ma, Lingling; Woo, Seong Ihl

    2014-08-27

    Mn-Ce-Ti mixed-oxide catalyst prepared by the hydrothermal method was investigated for the selective catalytic reduction (SCR) of NOx with NH3 in the presence of oxygen. It was found that the environmentally benign Mn-Ce-Ti catalyst exhibited excellent NH3-SCR activity and strong resistance against H2O and SO2 with a broad operation temperature window, which is very competitive for the practical application in controlling the NOx emission from diesel engines. On the basis of the catalyst characterization, the dual redox cycles (Mn(4+) + Ce(3+) ↔ Mn(3+) + Ce(4+), Mn(4+) + Ti(3+) ↔ Mn(3+) + Ti(4+)) and the amorphous structure play key roles for the high catalytic deNOx performance. Diffuse reflectance infrared Fourier transform spectroscopy studies showed that the synergetic effect between Mn and Ce contributes to the formation of reactive intermediate species, thus promoting the NH3-SCR to proceed.

  1. 40 CFR 51.122 - Emissions reporting requirements for SIP revisions relating to budgets for NOX emissions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... reporting requirements of 40 CFR part 75, then the state need not provide an every-year cycle report to EPA... SIP revisions relating to budgets for NOX emissions. 51.122 Section 51.122 Protection of Environment... relating to budgets for NOX emissions. (a) As used in this section, words and terms shall have the...

  2. Computer simulation as a NOx reduction design tool

    SciTech Connect

    Liu, G.; Higgins, B.S.

    2008-10-15

    Nalco Mobotec engineers were charged with reducing emissions on a utility boiler converted from burning oil to eastern bituminous coal using the company's Rotamix selective noncatalytic reduction (SNCR) system which injects urea into the furnace. A CFD simulation of the existing boiler was first conducted and then the furnace was simulated with the SNCR system added and the design was optimised. Operating and capital costs were minimised by optimal placement of 50 injector ports. 6 figs., 2 tabs.

  3. Control of NOx Emissions from Stationary Combustion Sources

    EPA Science Inventory

    In general, NOx control technologies are categorized as being either primary control technologies or secondary control technologies. Primary control technologies reduce the formation of NOx in the primary combustion zone. In contrast, secondary control technologies destroy the NO...

  4. Variation of radiative forcings and global warming potentials from regional aviation NOx emissions

    NASA Astrophysics Data System (ADS)

    Skowron, Agnieszka; Lee, David S.; De León, Ruben R.

    2015-03-01

    The response to hemispherical and regional aircraft NOx emissions is explored by using two climate metrics: radiative forcing (RF) and Global Warming Potential (GWP). The global chemistry transport model, MOZART-3 CTM, is applied in this study for a series of incremental aircraft NOx emission integrations to different regions. It was found that the sensitivity of chemical responses per unit emission rate from regional aircraft NOx emissions varies with size of aircraft NOx emission rate and that climate metric values decrease with increasing aircraft NOx emission rates, except for Southeast Asia. Previous work has recognized that aircraft NOx GWPs may vary regionally. However, the way in which these regional GWPs are calculated are critical. Previous studies have added a fixed amount of NOx to different regions. This approach can heavily bias the results of a regional GWP because of the well-established sensitivity of O3 production to background NOx whereby the Ozone Production Efficiency (OPE) is greater at small background NOx. Thus, even a small addition of NOx in a clean-air area can produce a large O3 response. Using this 'fixed addition' method of 0.035 Tg(N) yr-1, results in the greatest effect observed for North Atlantic and Brazil, ∼10.0 mW m-2/Tg(N) yr-1. An alternative 'proportional approach' is also taken that preserves the subtle balance of local NOx-O3-CH4 systems with the existing emission patterns of aircraft and background NOx, whereby a proportional amount of aircraft NOx, 5% (N) yr-1, is added to each region in order to determine the response. This results in the greatest effect observed for North Pacific that with its net NOx RF of 23.7 mW m-2/Tg(N) yr-1 is in contrast with the 'fixed addition' method. For determining regional NOx GWPs, it is argued that the 'proportional' approach gives more representative results. However, a constraint of both approaches is that the regional GWP determined is dependent on the relative global emission pattern

  5. Emission inventories of NOx from commercial energy consumption in China, 1995-1998.

    PubMed

    Hao, Jiming; Tian, Hezhong; Lu, Yongqi

    2002-02-15

    Emissions of nitrogen oxides (NOx) in China are of great concern because of their impact on local air pollution as well as on regional environmental risks such as acid rain, eutrophication, tropospheric ozone, fine particulate matter, and loss of biodiversity. In this paper, total anthropogenic emissions of NOx in China during the past two decades are estimated on the basis of commercial energy consumption and NOx emission factors of different sectors and fuel types. Specifically, emission inventories of NOx from 31 provinces, 7 economic sectors, and 11 fuel types from 1995 to 1998 are evaluated and analyzed in detail, and the distribution of provincial-based average NOx emission intensity in 1998 is presented. It can be seen that the calculated national total emissions of NOx have rapidly increased from 4.76 Mt in 1980 to a peak value of about 12.03 Mt in 1996, with an average annual growth rate of 6%. However, instead of increasing, NOx emissions in 1997 and 1998 decreased by 0.37 Mt and 0.85 Mt, respectively, as compared to the peak in 1996. In short, NOx emissions caused by energy use are mainly concentrated in the more populated and industrialized areas of China, i.e., the Eastern Central and Southeastern areas. These results imply that China's NOx emissions in the future may not become as high as previously expected which will be helpful for policy making to control local NOx pollution as well as to reduce acid rain and tropospheric ozone in East Asia.

  6. 40 CFR 75.17 - Specific provisions for monitoring emissions from common, bypass, and multiple stacks for NOX...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... emissions from common, bypass, and multiple stacks for NOX emission rate. 75.17 Section 75.17 Protection of..., and multiple stacks for NOX emission rate. Notwithstanding the provisions of paragraphs (a), (b), (c... this part to meet the monitoring and reporting requirements of a State or federal NOX mass...

  7. [NOx and SO2 formation in the sintering process and influence of sintering material composition on NOx emissions].

    PubMed

    Ren, Zhong-Pei; Zhu, Tian-Le; Zhu, Ting-Yu; Lü, Dong

    2014-10-01

    NOx and SO2 formation in the sintering process and the influence of coke powder content, moisture content and adding additives on NO emissions were investigated by the sintering pot experimental method. The results showed that the combustion zone moved downward along the sintering pot after the sintering started. The NOx concentrations of all monitoring points below the combustion zone were basically the same. SO2 generated in the combustion zone was adsorbed and accumulated in the sintering materials below the zone. Then, SO2 was released by pyrolysis, and finally discharged from the outlet of sintering pot. So the significant SO2 couldn't be detected before the burning through point, and the relationship between the SO2 concentration and the sintering time displayed an inverted "V" curve. NOx produced from the sintering process was mainly thermal-NOx, and most of it was NO, the NO2 concentration was very low. Reducing the coke powder and moisture contents, or adding sintering additives could effectively reduce NOx emissions.

  8. Ships going slow in reducing their NOx emissions: changes in 2005-2012 ship exhaust inferred from satellite measurements over Europe

    NASA Astrophysics Data System (ADS)

    Folkert Boersma, K.; Vinken, Geert C. M.; Tournadre, Jean

    2015-07-01

    We address the lack of temporal information on ship emissions, and report on rapid short-term variations of satellite-derived ship NOx emissions between 2005 and 2012 over European seas. Our inversion is based on OMI observed tropospheric NO2 columns and GEOS-Chem simulations. Average European ship NOx emissions increased by ˜15% from 2005 to 2008. This increase was followed by a reduction of ˜12% in 2009, a direct result of the global economic downturn in 2008-2009, and steady emissions from 2009 to 2012. Observations of ship passages through the Suez Canal and satellite altimeter derived ship densities suggests that ships in the Mediterranean Sea have reduced their speed by more than 30% since 2008. This reduction in ship speed is accompanied by a persistent 45% reduction of average, per ship NOx emission factors. Our results indicate that the practice of ‘slow steaming’, i.e. the lowering of vessel speed to reduce fuel consumption, has indeed been implemented since 2008, and can be detected from space. In spite of the implementation of slow steaming, one in seven of all NOx molecules emitted in Europe in 2012 originated from the shipping sector, up from one in nine in 2005. The growing share of the shipping contributions to the overall European NOx emissions suggests a need for the shipping sector to implement additional measures to reduce pollutant emissions at rates that are achieved by the road transport and energy producing sectors in Europe.

  9. NOx EMISSIONS PRODUCED WITH COMBUSTION OF POWDER RIVER BASIN COAL IN A UTILITY BOILER

    SciTech Connect

    John S. Nordin; Norman W. Merriam

    1997-04-01

    The objective of this report is to estimate the NOx emissions produced when Powder River Basin (PRB) coal is combusted in a utility boiler. The Clean Air Act regulations specify NOx limits of 0.45 lb/mm Btu (Phase I) and 0.40 lb/mm Btu (Phase II) for tangentially fired boilers, and 0.50 lb/mm 13tu (Phase II) and 0.46 lb/mm Btu (Phase II) for dry-bottom wall-fired boilers. The Clean Air Act regulations also specify other limits for other boiler types. Compliance for Phase I has been in effect since January 1, 1996. Compliance for Phase II goes into effect on January 1, 2000. Emission limits are expressed as equivalent NO{sub 2} even though NO (and sometimes N{sub 2}O) is the NOx species emitted during combustion. Regulatory agencies usually set even lower NOx emission limits in ozone nonattainment areas. In preparing this report, Western Research Institute (WRI) used published test results from utilities burning various coals, including PRB coal, using state-of-the art control technology for minimizing NOx emissions. Many utilities can meet Clean Air Act NOx emission limits using a combination of tight combustion control and low-NOx burners and by keeping furnaces clean (i.e., no slag buildup). In meeting these limits, some utilities also report problems such as increased carbon in their fly ash and excessive furnace tube corrosion. This report discusses utility experience. The theory of NOx emission formation during coal combustion as related to coal structure and how the coal is combusted is also discussed. From this understanding, projections are made for NOx emissions when processed PRB coal is combusted in a test similar to that done with other coals. As will be shown, there are a lot of conditions for achieving low NOx emissions, such as tight combustion control and frequent waterlancing of the furnace to avoid buildup of deposits.

  10. Sensitivity of NOx over the Indian Ocean to emissions from the surrounding continents and nonlinearities in atmospheric chemistry responses

    NASA Astrophysics Data System (ADS)

    Kunhikrishnan, T.; Lawrence, M. G.

    2004-08-01

    The sensitivity of the Indian Ocean atmospheric chemistry to continental NOx emissions is examined using a global chemistry-transport model (MATCH-MPIC). NOx responds nonlinearly to changes in emissions, since O3 and OH, which depend on NOx, influence its lifetime. Due to this feedback and the contribution from other NOx sources (e.g., lightning), much of the Indian Ocean lower troposphere (LT) is only weakly sensitive to continental NOx emissions. In contrast to INDOEX (Indian Ocean Experiment) results for aerosols, CO, etc., during the winter monsoon the central Indian Ocean (CIO) is weakly sensitivity to Indian NOx emissions. However, the Bay of Bengal LT is very sensitive to NOx emissions from India (summer) and SE Asia and China (winter). Higher up, NOx over the CIO is most sensitive to African and SE Asian emissions, while the northern regions are influenced by the summer monsoon plume from India, SE Asia and China.

  11. Atmospheric emissions from a passenger ferry with selective catalytic reduction.

    PubMed

    Nuszkowski, John; Clark, Nigel N; Spencer, Thomas K; Carder, Daniel K; Gautam, Mridul; Balon, Thomas H; Moynihan, Paul J

    2009-01-01

    The two main propulsion engines on Staten Island Ferry Alice Austen (Caterpillar 3516A, 1550 hp each) were fitted with selective catalytic reduction (SCR) aftertreatment technology to reduce emissions of oxides of nitrogen (NOx). After the installation of the SCR system, emissions from the ferry were characterized both pre- and post-aftertreatment. Prior research has shown that the ferry operates in four modes, namely idle, acceleration, cruise, and maneuvering modes. Emissions were measured for both engines (designated NY and SI) and for travel in both directions between Manhattan and Staten Island. The emissions characterization used an analyzer system, a data logger, and a filter-based particulate matter (PM) measurement system. The measurement of NOx, carbon monoxide (CO), and carbon dioxide (CO2) were based on federal reference methods. With the existing control strategy for the SCR urea injection, the SCR provided approximately 64% reduction of NOx for engine NY and 36% reduction for engine SI for a complete round trip with less than 6.5 parts per million by volume (ppmv) of ammonia slip during urea injection. Average reductions during the cruise mode were 75% for engine NY and 47% for engine SI, which was operating differently than engine NY. Reductions for the cruise mode during urea injection typically exceeded 94% from both engines, but urea was injected only when the catalyst temperature reached a 300 degrees C threshold pre- and postcatalyst. Data analysis showed a total NOx mass emission split with 80% produced during cruise, and the remaining 20% spread across idle, acceleration, and maneuvering. Examination of continuous NOx data showed that higher reductions of NOx could be achieved on both engines by initiating the urea injection at an earlier point (lower exhaust temperature) in the acceleration and cruise modes of operation. The oxidation catalyst reduced the CO production 94% for engine NY and 82% for engine SI, although the high CO levels

  12. Power plant emissions reduction

    SciTech Connect

    Anand, Ashok Kumar; Nagarjuna Reddy, Thirumala Reddy

    2015-10-20

    A system for improved emissions performance of a power plant generally includes an exhaust gas recirculation system having an exhaust gas compressor disposed downstream from the combustor, a condensation collection system at least partially disposed upstream from the exhaust gas compressor, and a mixing chamber in fluid communication with the exhaust gas compressor and the condensation collection system, where the mixing chamber is in fluid communication with the combustor.

  13. The observed response of ozone production to the policy-driven decrease of NOx and CO emissions in the Baltimore/Washington area

    NASA Astrophysics Data System (ADS)

    Roberts, S. J.; Hosley, K.; Ren, X.; Wolfe, G.; Dickerson, R. R.; Salawitch, R. J.

    2015-12-01

    The nonlinearity of ozone production has important policy implications as cities continue to decrease NOx, CO, and other important ozone precursors. Observations in the Baltimore/Washington area from 1970 through 2014 demonstrate reductions in NOx and CO emissions due to policy implementation leading to dramatic improvement in air quality. We will analyze the response of the reactivity of ozone, NOx, and VOC to these emission reductions in the Baltimore/Washington area using the University of Washington Chemical Model (UWCMv2.2). This model allows us to evaluate this response using multiple gas-phase chemical mechanisms. With this model, we will also compare and contrast the response of modeled ozone to reduced NOx and CO concentrations across multiple chemical mechanisms.

  14. Fundamental limits on gas-phase chemical reduction of NOx in a plasma

    SciTech Connect

    Penetrante, B.M.; Hsiao, M.C.; Merritt, B.T.; Vogtlin, G.E.

    1997-12-31

    In the plasma, the electrons do not react directly with the NOx molecules. The electrons collide mainly with the background gas molecules like N{sub 2}, O{sub 2} and H{sub 2}O. Electron impact on these molecules result partly in dissociation reactions that produce reactive species like N, O and OH. The NOx in the engine exhaust gas initially consist mostly of NO. The ground state nitrogen atom, N, is the only species that could lead to the chemical reduction of NO to N{sub 2}. The O radical oxidizes NO to NO{sub 2} leaving the same amount of NOx. The OH radical converts NO{sub 2} to nitric acid. Acid products in the plasma can easily get adsorbed on surfaces in the plasma reactor and in the pipes. When undetected, the absence of these oxidation products can often be mistaken for chemical reduction of NOx. In this paper the authors will examine the gas-phase chemical reduction of NOx. They will show that under the best conditions, the plasma can chemically reduce 1.6 grams of NOx per brake-horsepower-hour [g(NOx)/bhp-hr] when 5% of the engine output energy is delivered to the plasma.

  15. Emissions reductions from expanding state-level renewable portfolio standards.

    PubMed

    Johnson, Jeremiah X; Novacheck, Joshua

    2015-05-01

    In the United States, state-level Renewable Portfolio Standards (RPS) have served as key drivers for the development of new renewable energy. This research presents a method to evaluate emissions reductions and costs attributable to new or expanded RPS programs by integrating a comprehensive economic dispatch model and a renewable project selection model. The latter model minimizes incremental RPS costs, accounting for renewable power purchase agreements (PPAs), displaced generation and capacity costs, and net changes to a state's imports and exports. We test this method on potential expansions to Michigan's RPS, evaluating target renewable penetrations of 10% (business as usual or BAU), 20%, 25%, and 40%, with varying times to completion. Relative to the BAU case, these expanded RPS policies reduce the CO2 intensity of generation by 13%, 18%, and 33% by 2035, respectively. SO2 emissions intensity decreased by 13%, 20%, and 34% for each of the three scenarios, while NOx reductions totaled 12%, 17%, and 31%, relative to the BAU case. For CO2 and NOx, absolute reductions in emissions intensity were not as large due to an increasing trend in emissions intensity in the BAU case driven by load growth. Over the study period (2015 to 2035), the absolute CO2 emissions intensity increased by 1% in the 20% RPS case and decreased by 6% and 22% for the 25% and 40% cases, respectively. Between 26% and 31% of the CO2, SO2, and NOx emissions reductions attributable to the expanded RPS occur in neighboring states, underscoring the challenges quantifying local emissions reductions from state-level energy policies with an interconnected grid. Without federal subsidies, the cost of CO2 mitigation using an RPS in Michigan is between $28 and $34/t CO2 when RPS targets are met. The optimal renewable build plan is sensitive to the capacity credit for solar but insensitive to the value for wind power. PMID:25884101

  16. Emissions reductions from expanding state-level renewable portfolio standards.

    PubMed

    Johnson, Jeremiah X; Novacheck, Joshua

    2015-05-01

    In the United States, state-level Renewable Portfolio Standards (RPS) have served as key drivers for the development of new renewable energy. This research presents a method to evaluate emissions reductions and costs attributable to new or expanded RPS programs by integrating a comprehensive economic dispatch model and a renewable project selection model. The latter model minimizes incremental RPS costs, accounting for renewable power purchase agreements (PPAs), displaced generation and capacity costs, and net changes to a state's imports and exports. We test this method on potential expansions to Michigan's RPS, evaluating target renewable penetrations of 10% (business as usual or BAU), 20%, 25%, and 40%, with varying times to completion. Relative to the BAU case, these expanded RPS policies reduce the CO2 intensity of generation by 13%, 18%, and 33% by 2035, respectively. SO2 emissions intensity decreased by 13%, 20%, and 34% for each of the three scenarios, while NOx reductions totaled 12%, 17%, and 31%, relative to the BAU case. For CO2 and NOx, absolute reductions in emissions intensity were not as large due to an increasing trend in emissions intensity in the BAU case driven by load growth. Over the study period (2015 to 2035), the absolute CO2 emissions intensity increased by 1% in the 20% RPS case and decreased by 6% and 22% for the 25% and 40% cases, respectively. Between 26% and 31% of the CO2, SO2, and NOx emissions reductions attributable to the expanded RPS occur in neighboring states, underscoring the challenges quantifying local emissions reductions from state-level energy policies with an interconnected grid. Without federal subsidies, the cost of CO2 mitigation using an RPS in Michigan is between $28 and $34/t CO2 when RPS targets are met. The optimal renewable build plan is sensitive to the capacity credit for solar but insensitive to the value for wind power.

  17. Impact of passenger car NOx emissions and NO2 fractions on urban NO2 pollution - Scenario analysis for the city of Antwerp, Belgium

    NASA Astrophysics Data System (ADS)

    Degraeuwe, Bart; Thunis, Philippe; Clappier, Alain; Weiss, Martin; Lefebvre, Wouter; Janssen, Stijn; Vranckx, Stijn

    2016-02-01

    The annual NO2 concentrations in many European cities exceed the established air quality standard. This situation is mainly caused by Diesel cars whose NOx emissions are higher on the road than during type approval in the laboratory. Moreover, the fraction of NO2 in the NOx emissions of modern diesel cars appears to have increased as compared to previous models. In this paper, we assess 1) to which level the distance-specific NOx emissions of Diesel cars should be reduced to meet established air quality standards and 2) if it would be useful to introduce a complementary NO2 emissions limit. We develop a NO2 pollution model that accounts in an analysis of 9 emission scenarios for changes in both, the urban background NO2 concentrations and the local NO2 emissions at street level. We apply this model to the city of Antwerp, Belgium. The results suggest that a reduction in NOx emissions decreases the regional and urban NO2 background concentration; high NO2 fractions increase the ambient NO2 concentrations only in close spatial proximity to the emission source. In a busy access road to the city centre, the average NO2 concentration can be reduced by 23% if Diesel cars emitted 0.35 g NOx/km instead of the current 0.62 g NOx/km. Reductions of 45% are possible if the NOX emissions of Diesel cars decreased to the level of gasoline cars (0.03 g NOx/km). Our findings suggest that the Real-Driving Emissions (RDE) test procedure can solve the problem of NO2 exceedances in cities if it reduced the on-road NOx emissions of diesel cars to the permissible limit of 0.08 g/km. The implementation of a complementary NO2 emissions limit may then become superfluous. If Diesel cars continue to exceed by several factors their NOx emissions limit on the road, a shift of the vehicle fleet to gasoline cars may be necessary to solve persisting air quality problems.

  18. Combining nonthermal plasma with perovskite-like catalyst for NOx storage and reduction.

    PubMed

    Peng, Han Hsuan; Pan, Kuan Lun; Yu, Sheng Jen; Yan, Shaw Yi; Chang, Moo Been

    2016-10-01

    A new NOx storage and reduction (NSR) system is developed for NOx removal by combining perovskite-like catalyst with nonthermal plasma technology. In this hybrid system, catalyst is mainly used for oxidizing NO to NO2 and storing them, while nonthermal plasma is applied as a desorption-reduction step for converting NOx into N2. An innovative catalyst with a high NOx storage capacity and good reduction performance is developed by successive impregnation. The catalysts prepared with various metal oxides were investigated for NOx storage capacity (NSC) and NOx conversion. Characterization of the catalysts prepared reveals that addition of cobalt (Co) and potassium (K) considerably increases the performance for NSC. Results also show that SrKMn0.8Co0.2O4 supported on BaO/Al2O3 has good NSC (209 μmol/gcatalyst) for the gas stream containing 500 ppm NO and 5 % O2 with N2 as carrier gas. For plasma reduction process, NOx conversion achieved with SrKMn0.8Co0.2O4/BaO/Al2O3 reaches 81 % with the applied voltage of 12 kV and frequency of 6 kHz in the absence of reducing agents. The results indicate that performance of plasma reduction process (81 %) is better than that of thermal reduction (64 %). Additionally, mixed gases including 1 % CO, 1 % H2 and 1 % CH4, and 2 % H2O(g) are simultaneously introduced into the system to investigate the effect on NSR with plasma system and results indicate that performance of NSR with plasma can be enhanced. Overall, the hybrid system is promising to be applied for removing NOx from gas streams. Graphical abstract ᅟ. PMID:27392625

  19. Combining nonthermal plasma with perovskite-like catalyst for NOx storage and reduction.

    PubMed

    Peng, Han Hsuan; Pan, Kuan Lun; Yu, Sheng Jen; Yan, Shaw Yi; Chang, Moo Been

    2016-10-01

    A new NOx storage and reduction (NSR) system is developed for NOx removal by combining perovskite-like catalyst with nonthermal plasma technology. In this hybrid system, catalyst is mainly used for oxidizing NO to NO2 and storing them, while nonthermal plasma is applied as a desorption-reduction step for converting NOx into N2. An innovative catalyst with a high NOx storage capacity and good reduction performance is developed by successive impregnation. The catalysts prepared with various metal oxides were investigated for NOx storage capacity (NSC) and NOx conversion. Characterization of the catalysts prepared reveals that addition of cobalt (Co) and potassium (K) considerably increases the performance for NSC. Results also show that SrKMn0.8Co0.2O4 supported on BaO/Al2O3 has good NSC (209 μmol/gcatalyst) for the gas stream containing 500 ppm NO and 5 % O2 with N2 as carrier gas. For plasma reduction process, NOx conversion achieved with SrKMn0.8Co0.2O4/BaO/Al2O3 reaches 81 % with the applied voltage of 12 kV and frequency of 6 kHz in the absence of reducing agents. The results indicate that performance of plasma reduction process (81 %) is better than that of thermal reduction (64 %). Additionally, mixed gases including 1 % CO, 1 % H2 and 1 % CH4, and 2 % H2O(g) are simultaneously introduced into the system to investigate the effect on NSR with plasma system and results indicate that performance of NSR with plasma can be enhanced. Overall, the hybrid system is promising to be applied for removing NOx from gas streams. Graphical abstract ᅟ.

  20. 40 CFR 97.424 - Compliance with TR NOX Annual emissions limitation.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 21 2014-07-01 2014-07-01 false Compliance with TR NOX Annual emissions limitation. 97.424 Section 97.424 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... accounting basis in the following order: (i) Any TR NOX Annual allowances that were allocated to the units...

  1. 40 CFR 97.354 - Compliance with CAIR NOX emissions limitation.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 21 2014-07-01 2014-07-01 false Compliance with CAIR NOX emissions limitation. 97.354 Section 97.354 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... section, on a first-in, first-out (FIFO) accounting basis in the following order: (i) Any CAIR NOX...

  2. 40 CFR 96.354 - Compliance with CAIR NOX emissions limitation.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 21 2014-07-01 2014-07-01 false Compliance with CAIR NOX emissions limitation. 96.354 Section 96.354 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... section, on a first-in, first-out (FIFO) accounting basis in the following order: (i) Any CAIR NOX...

  3. 40 CFR 97.424 - Compliance with TR NOX Annual emissions limitation.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 22 2013-07-01 2013-07-01 false Compliance with TR NOX Annual emissions limitation. 97.424 Section 97.424 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... accounting basis in the following order: (i) Any TR NOX Annual allowances that were allocated to the units...

  4. 40 CFR 97.154 - Compliance with CAIR NOX emissions limitation.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 21 2014-07-01 2014-07-01 false Compliance with CAIR NOX emissions limitation. 97.154 Section 97.154 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR...) accounting basis in the following order: (i) Any CAIR NOX allowances that were allocated to the units at...

  5. 40 CFR 97.354 - Compliance with CAIR NOX emissions limitation.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Ozone Season Allowance Tracking System § 97.354 Compliance with CAIR NOX emissions limitation. (a... under paragraph (d)(1) of this section shall not affect the liability of the owners and operators of the... Administrator may review and conduct independent audits concerning any submission under the CAIR NOX...

  6. 40 CFR 97.154 - Compliance with CAIR NOX emissions limitation.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Allowance Tracking System § 97.154 Compliance with CAIR NOX emissions limitation. (a) Allowance transfer... required under paragraph (d)(1) of this section shall not affect the liability of the owners and operators... conduct independent audits concerning any submission under the CAIR NOX Annual Trading Program and...

  7. Effects of Coaxial Air on Nitrogen-Diluted Hydrogen Jet Diffusion Flame Length and NOx Emission

    SciTech Connect

    Weiland, N.T.; Chen, R.-H.; Strakey, P.A.

    2007-10-01

    Turbulent nitrogen-diluted hydrogen jet diffusion flames with high velocity coaxial air flows are investigated for their NOx emission levels. This study is motivated by the DOE turbine program’s goal of achieving 2 ppm dry low NOx from turbine combustors running on nitrogen-diluted high-hydrogen fuels. In this study, effects of coaxial air velocity and momentum are varied while maintaining low overall equivalence ratios to eliminate the effects of recirculation of combustion products on flame lengths, flame temperatures, and resulting NOx emission levels. The nature of flame length and NOx emission scaling relationships are found to vary, depending on whether the combined fuel and coaxial air jet is fuel-rich or fuel-lean. In the absence of differential diffusion effects, flame lengths agree well with predicted trends, and NOx emissions levels are shown to decrease with increasing coaxial air velocity, as expected. Normalizing the NOx emission index with a flame residence time reveals some interesting trends, and indicates that a global flame strain based on the difference between the fuel and coaxial air velocities, as is traditionally used, is not a viable parameter for scaling the normalized NOx emissions of coaxial air jet diffusion flames.

  8. Effect of B20 and Low Aromatic Diesel on Transit Bus NOx Emissions Over Driving Cycles with a Range of Kinetic Intensity

    SciTech Connect

    Lammert, M. P.; McCormick, R. L.; Sindler, P.; Williams, A.

    2012-10-01

    Oxides of nitrogen (NOx) emissions for transit buses for up to five different fuels and three standard transit duty cycles were compared to establish whether there is a real-world biodiesel NOx increase for transit bus duty cycles and engine calibrations. Six buses representing the majority of the current national transit fleet and including hybrid and selective catalyst reduction systems were tested on a heavy-duty chassis dynamometer with certification diesel, certification B20 blend, low aromatic (California Air Resources Board) diesel, low aromatic B20 blend, and B100 fuels over the Manhattan, Orange County and UDDS test cycles. Engine emissions certification level had the dominant effect on NOx; kinetic intensity was the secondary driving factor. The biodiesel effect on NOx emissions was not statistically significant for most buses and duty cycles for blends with certification diesel, except for a 2008 model year bus. CARB fuel had many more instances of a statistically significant effect of reducing NOx. SCR systems proved effective at reducing NOx to near the detection limit on all duty cycles and fuels, including B100. While offering a fuel economy benefit, a hybrid system significantly increased NOx emissions over a same year bus with a conventional drivetrain and the same engine.

  9. Fluidized combustion of coal. [to limit SO2 and NOx emissions

    NASA Technical Reports Server (NTRS)

    Pope, M.

    1978-01-01

    A combustion technology that permits the burning of low quality coal, and other fuels, while maintaining stack emissions within State and Federal EPA limits is discussed. Low quality fuels can be burned directly in fluidized beds while taking advantage of low furnace temperatures and chemical activity within the bed to limit SO2 and NOx emissions. The excellent heat transfer characteristics of the fluidized beds also result in a reduction of total heat transfer surface requirements. Tests on beds operating at pressures of one to ten atmospheres, at temperatures as high as 1600 F, and with gas velocities in the vicinity of four to twelve feet per second, have proven the concept. The progress that has been made in the development of fluidized bed combustion technology and work currently underway are discussed.

  10. Evaluation of on-road vehicle CO and NOx National Emission Inventories using an urban-scale source-oriented air quality model

    NASA Astrophysics Data System (ADS)

    Kota, Sri Harsha; Zhang, Hongliang; Chen, Gang; Schade, Gunnar W.; Ying, Qi

    2014-03-01

    The MOBILE6.2 model was replaced by the Motor Vehicle Emission Simulator (MOVES) in 2012 as an official tool recommended by the United States Environmental Protection Agency (US EPA) to predict vehicular pollutant emission factors. In this study, on-road vehicle emission inventories of CO and NOx for Southeast Texas generated by MOVES and MOBILE6.2 in two versions of the 2005 National Emission Inventory (NEI) were studied by comparing predicted CO and NOx using the EPA's Community Multiscale Air Quality (CMAQ) Model incorporated with a source-oriented gas phase chemical mechanism with measurements made at six urban and industrial sites in Southeast Texas. The source tracing technique allows direct determination of contributions of on-road vehicles to overall CO and NOx concentrations and identification of ambient concentration measurements which are mostly impacted by vehicle emissions. By grouping the fractional bias (FB) values of the hourly predictions based on vehicle contributions to total CO or NOx concentrations, clear trends in the FB were observed, indicating systematic biases in the emission inventory for these species. Data points dominated by vehicle emissions suggest that surface CO concentrations due to vehicle exhaust are significantly over-estimated by a factor of 2 using either MOVES or MOBILE6.2. NOx concentrations are overestimated by approximately 20-35% and 70% by using the MOBILE6.2 and MOVES emissions, respectively. Emission scaling runs show that a domain-wide reduction of MOBILE6.2 CO emissions by 60% and NOx emissions by 15-25% leads to better model performance of exhaust CO and NOx concentrations in the current study.

  11. Collection of NO and NO2 for isotopic analysis of NO(x) emissions.

    PubMed

    Fibiger, Dorothy L; Hastings, Meredith G; Lew, Audrey F; Peltier, Richard E

    2014-12-16

    There have been several measurements made of the nitrogen isotopic composition of gaseous NOx (NOx = NO + NO2) from various emission sources, utilizing a wide variety of methods to collect the NOx in solution as nitrate or nitrite. However, previous collection techniques have not been verified for complete or efficient capture of NOx such that the isotopic composition of NOx remains unaltered during collection. Here, we present a method of collecting NOx (NO + NO2) in solution as nitrate to evaluate the nitrogen isotopic composition of the NOx (δ(15)N-NOx). Using a 0.25 M KMnO4 and 0.5 M NaOH solution, quantitative NOx collection was achieved under a variety of conditions in laboratory and field settings, allowing for isotopic analysis without correcting for fractionations. The uncertainty across the entire analytic procedure is ±1.5‰ (1σ). With this method, a more robust inventory of NOx source isotopic composition is possible, which has implications for studies of air quality and acid deposition. PMID:25415365

  12. THE ACID RAIN NOX PROGRAM

    EPA Science Inventory

    Between 350,000 and 400,000 tons of annual NOx emissions have been eliminated as a result of Phase I of the Acid Rain NOx Program. As expected. the utilities have chosen emissions averaging as the primary compliance option. This reflects that, in general, NO x reductions have ...

  13. Don't NOx Texas

    SciTech Connect

    Mathis, J.D.; Lachowicz, Y.

    2005-07-01

    Modifications to boiler combustion systems allow Fayette Power Projects units 1 and 2 to meet new NOx emissions limits east of La Grange in Eastern Texas. The article describes modifications executed by Alstom in 2004 which attained an overall reduction in NOx emissions of almost 69%. 4 figs., 1 tab., 1 photo.

  14. Characterization of NOx emission in the suburbs of Tokyo based on simultaneous and real-time observations of atmospheric Ox and NOx

    NASA Astrophysics Data System (ADS)

    Matsumoto, J.

    2013-12-01

    Nitrogen oxides, NOx (NO, NO2), and volatile organic compounds, VOCs, are important as precursors of photochemical oxidants (tropospheric ozone, O3). To predict and control photochemical oxidants, NOx emission should be captured precisely. In addition, the ratio of NO2/NOx in the exhaust gas is also important as the initial balance between NO and NO2 in the atmosphere. Monitoring the NO2/NOx ratio in the exhaust gases is essential. Especially, the influence of the NOx emission on the real atmosphere should be explored. However, conversion reactions among NO, NO2 and O3 are typically in the time scale of minutes. The NO2/NOx ratio can change rapidly just after emission. Real-time observations of these compounds in the second time scale are essential. In view of photochemical oxidant, near emission sources of NO, ozone concentration can be easily perturbed by reaction with locally emitted NO. As an index of oxidant, the sum of O3 and NO2 (Ox = O3 + NO2) is useful. In this study, a simultaneous and real-time analyzer of atmospheric Ox and NOx has been developed utilizing the dual NO2 detectors based on laser-induced fluorescence technique (LIF), and characterization of NOx emission was explored through the observations of Ox and NOx in the suburbs of Tokyo. The dual LIF detectors consisted of one laser head, two LIF cells, and one common vacuum pump. As the Ox monitor, the excess NO was added to the sample and O3 was converted to NO2, and then the sum of O3 and NO2 in the sample was quantified at the 1st LIF cell. As the NOx monitor, the excess O3 was added to the sample and NO was converted to NO2, and then the sum of NO and NO2 in the sample was quantified at the 2nd LIF cell. Both the ';Ox' and ';NOx' channels in the dual LIF analyzer were simultaneously monitoring Ox and NOx in the sample air, respectively. The temporal resolution of observed data was 1 s. Typical conversion efficiencies of O3 and NO to NO2 were more than 0.98. The lower detection limits were 0

  15. 40 CFR 51.10 - How does my state report emissions that are required by the NOX SIP Call?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... are required by the NOX SIP Call? 51.10 Section 51.10 Protection of Environment ENVIRONMENTAL... does my state report emissions that are required by the NOX SIP Call? The District of Columbia and states that are subject to the NOX SIP Call § 51.121) are subject to the emissions reporting...

  16. 40 CFR 51.10 - How does my state report emissions that are required by the NOX SIP Call?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... are required by the NOX SIP Call? 51.10 Section 51.10 Protection of Environment ENVIRONMENTAL... does my state report emissions that are required by the NOX SIP Call? The District of Columbia and states that are subject to the NOX SIP Call § 51.121) are subject to the emissions reporting...

  17. 40 CFR 51.10 - How does my state report emissions that are required by the NOX SIP Call?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... are required by the NOX SIP Call? 51.10 Section 51.10 Protection of Environment ENVIRONMENTAL... does my state report emissions that are required by the NOX SIP Call? The District of Columbia and states that are subject to the NOX SIP Call § 51.121) are subject to the emissions reporting...

  18. Novel fluidized bed reactor for integrated NOx adsorption-reduction with hydrocarbons

    SciTech Connect

    Terris T. Yang; Hsiaotao T. Bi

    2009-07-01

    In order to avoid the negative impact of excessive oxygen in the combustion flue gases on the selectivity of most hydrocarbon selective catalytic reduction (HC-SCR) catalysts, an integrated NOx adsorption-reduction process has been proposed in this study for the treatment of flue gases under lean burn conditions by decoupling the adsorption and reduction into two different zones. The hypothesis has been validated in a novel internal circulating fluidized bed (ICFB) reactor using Fe/ZSM-5 as the catalyst and propylene as the reducing agent. Effects of propylene to the NOx molar ratio, flue gas oxygen concentration, and gas velocity on NOx conversion were studied using simulated flue gases. The results showed that increasing the ratio of HC:NO improved the reduction performance of Fe/ZSM-5 in the ICFB reactor. NOx conversion decreased with an increasing flue gas flow velocity in the annulus U{sub A} but increased with an increasing reductant gas flow velocity in the draft tube U{sub D}. The NOx adsorption ratio decreased with increasing U{sub A}. In most cases, NOx conversion was higher than the adsorption ratio due to the relatively poor adsorption performance of the catalyst. Fe/ZSM-5 showed a promising reduction performance and a strong inhibiting ability on the negative impact of excessive O{sub 2} in the ICFB reactor, proving that such an ICFB reactor possessed the ability to overcome the negative impact of excessive O{sub 2} in the flue gas using Fe/ZSM-5 as the deNOx catalyst. 22 refs., 10 figs.

  19. REDUCTION OF EMISSIONS FROM A HIGH SPEED FERRY

    SciTech Connect

    Thompson,G.; Gautam, M; Clark, N; Lyons, D; Carder, D; Riddle, W; Barnett, R; Rapp, B; George, S

    2003-08-24

    Emissions from marine vessels are being scrutinized as a major contributor to the total particulate matter (TPM), oxides of sulfur (SOx) and oxides of nitrogen (NOx) environmental loading. Fuel sulfur control is the key to SOx reduction. Significant reductions in the emissions from on-road vehicles have been achieved in the last decade and the emissions from these vehicles will be reduced by another order of magnitude in the next five years: these improvements have served to emphasize the need to reduce emissions from other mobile sources, including off road equipment, locomotives, and marine vessels. Diesel-powered vessels of interest include ocean going vessels with low- and medium-speed engines, as well as ferries with high speed engines, as discussed below. A recent study examined the use of intake water injection (WIS) and ultra low sulfur diesel (ULSD) to reduce the emissions from a high-speed passenger ferry in southern California. One of the four Detroit Diesel 12V92 two-stroke high speed engines that power the Waverider (operated by SCX, inc.) was instrumented to collect intake airflow, fuel flow, shaft torque, and shaft speed. Engine speed and shaft torque were uniquely linked for given vessel draft and prevailing wind and sea conditions. A raw exhaust gas sampling system was utilized to measure the concentration of NOx, carbon dioxide (CO2), and oxygen (O2) and a mini dilution tunnel sampling a slipstream from the raw exhaust was used to collect TPM on 70 mm filters. The emissions data were processed to yield brake-specific mass results. The system that was employed allowed for redundant data to be collected for quality assurance and quality control. To acquire the data, the Waverider was operated at five different steady state speeds. Three modes were in the open sea off Oceanside, CA, and idle and harbor modes were also used. Data have showed that the use of ULSD along with water injection (WIS) could significantly reduce the emissions of NOx and PM

  20. Shifting primary energy source and NOx emission location with plug-in hybrid vehicles

    NASA Astrophysics Data System (ADS)

    Karman, Deniz

    2011-06-01

    Plug-in hybrid vehicles (PHEVs) present an interesting technological opportunity for using non-fossil primary energy in light duty passenger vehicles, with the associated potential for reducing air pollutant and greenhouse gas emissions, to the extent that the electric power grid is fed by non-fossil sources. This perspective, accompanying the article by Thompson et al (2011) in this issue, will touch on two other studies that are directly related: the Argonne study (Elgowainy et al 2010) and a PhD thesis from Utrecht (van Vliet 2010). Thompson et al (2011) have examined air quality effects in a case where the grid is predominantly fossil fed. They estimate a reduction of 7.42 tons/day of NOx from motor vehicles as a result of substituting electric VMTs for 20% of the light duty gasoline vehicle miles traveled. To estimate the impact of this reduction on air quality they also consider the increases in NOx emissions due to the increased load on electricity generating units. The NOx emission increases are estimated as 4.0, 5.5 and 6.3 tons for the Convenience, Battery and Night charging scenarios respectively. The net reductions are thus in the 1.1-3.4 tons/day range. The air quality modelling results presented show that the air quality impact from a ground-level ozone perspective is favorable overall, and while the effect is stronger in some localities, the difference between the three scenarios is small. This is quite significant and suggests that localization of the NOx emissions to point sources has a more pronounced effect than the absolute reductions achieved. Furthermore it demonstrates that localization of NOx emissions to electricity generating units by using PHEVs in vehicle traffic has beneficial effects for air quality not only by minimizing direct human exposure to motor vehicle emissions, but also due to reduced exposure to secondary pollutants (i.e. ozone). In an electric power grid with a smaller share of fossil fired generating units, the beneficial

  1. Emission reduction for small utility two-stroke engine

    SciTech Connect

    Tamba, Shinichi; Yamamoto, Masaru; Yuasa, Tsuneyoshi; Yoshimizu, Isao

    1995-12-31

    As a result of the authors` research into reduction of exhaust emissions for small utility two-stroke engines which are widely used for handheld equipment such as a brush cutter and a hedge trimmer, they here discuss how much exhaust emissions can be reduced with only minor modifications of an engine. For the purpose of reducing emissions, they evaluated the effects of exhaust timing retard and of enleanment of carburetor mixture on mass emissions using the existing 25cc two-stroke engine, which emits high levels of HC and CO, and substantially low levels of NOx. The authors attained great reduction of HC and CO. The power output, however, dropped and both the plug seat and the exhaust gas temperatures rose, which would detract the practicability of the engine. But the authors solved the problems by modifying the combustion chamber and the exhaust port shape, keeping the emissions reduced as mentioned above.

  2. Decreasing emissions of NOx relative to CO2 in East Asia inferred from satellite observations

    NASA Astrophysics Data System (ADS)

    Reuter, M.; Buchwitz, M.; Hilboll, A.; Richter, A.; Schneising, O.; Hilker, M.; Heymann, J.; Bovensmann, H.; Burrows, J. P.

    2014-11-01

    At present, global CO2 emission inventories are mainly based on bottom-up estimates that rely, for example, on reported fossil fuel consumptions and fuel types. The associated uncertainties propagate into the CO2-to-NOx emission ratios that are used in pollution prediction and monitoring, as well as into biospheric carbon fluxes derived by inverse models. Here we analyse simultaneous and co-located satellite retrievals from SCIAMACHY (ref. ; SCanning Imaging Absorption SpectroMeter for Atmospheric CHartographY) of the column-average dry-air mole fraction of CO2 (refs , ) and NO2 (refs , , ) for the years 2003-2011 to provide a top-down estimate of trends in emissions and in the ratio between CO2 and NOx emissions. Our analysis shows that the CO2-to-NOx emission ratio has increased by 4.2 +/- 1.7% yr-1 in East Asia. In this region, we find a large positive trend of CO2 emissions (9.8 +/- 1.7% yr-1), which we largely attribute to the growing Chinese economy. This trend exceeds the positive trend of NOx emissions (5.8 +/- 0.9% yr-1). Our findings suggest that the recently installed and renewed technology in East Asia, such as power plants, transportation and so on, is cleaner in terms of NOx emissions than the old infrastructure, and roughly matches relative emission levels in North America and Europe.

  3. The impact of global aviation NOx emissions on tropospheric composition changes from 2005 to 2011

    NASA Astrophysics Data System (ADS)

    Wasiuk, D. K.; Khan, M. A. H.; Shallcross, D. E.; Lowenberg, M. H.

    2016-09-01

    The impact of aviation NOx emissions from 2005 to 2011 on the chemical composition of the atmosphere has been investigated on the basis of integrations of the 3-D global chemical and transport model, STOCHEM-CRI with the novel CRIv2-R5 chemistry scheme. A base case simulation without aircraft NOx emissions and integrations with NOx emissions from aircraft are inter-compared. The sensitivity of the global atmosphere to varying the quantity and the geographical distribution of the global annual aviation NOx emissions is assessed by performing, for the first time, a series of integrations based on changing the total mass and distribution of aircraft NOx emissions derived from air traffic movements recorded between 2005 and 2011. The emissions of NOx from the global fleet based on actual records of air traffic movements between 2005 and 2011 increased the global tropospheric annual mean burden of O3 by 1.0 Tg and decreased the global tropospheric annual mean burden of CH4 by 2.5 Tg. The net NOy and O3 production increases by 0.5% and 1%, respectively between 2005 and 2011 in total. At cruise altitude, the absolute increase in the modelled O3 mixing ratios is found to be up to 0.7 ppb between 2005 and 2011 at 25°N-50°N.

  4. Evaluating Texas NOx emissions using satellite-based observations and model simulations

    NASA Astrophysics Data System (ADS)

    Frost, G. J.; Kim, S.; McKeen, S.; Cooper, O.; Hsie, E.; Trainer, M.; Heckel, A.; Richter, A.; Burrows, J.; Gleason, J.

    2008-12-01

    Anthropogenic NOx is produced primarily from fossil fuel combustion by motor vehicles, power generation, and industrial processes. Satellite-based measurements have been used to assess NOx emission trends on regional to global spatial scales and daily to annual temporal scales. The small horizontal footprints of current satellite-borne instruments, including SCIAMACHY and OMI, can be used to detect NO2 resulting from NOx emitted by isolated point sources and metropolitan areas in the western US. In this study we examine NOx emissions in the state of Texas by comparing NO2 vertical columns retrieved from these satellite instruments to those predicted by a regional chemical-transport model. Comparisons of satellite-derived and model- calculated NO2 columns over US power plants, where in-stack emission monitoring is carried out, enables a critical evaluation of the key parameters leading to uncertainties in the satellite and model data products. By using the satellite retrieval algorithms and model configurations that produce the best agreement in NO2 columns over power plants in northeastern Texas and elsewhere in the western US, satellite-model comparisons of NO2 columns over Texas cities in turn allow urban NOx emission inventories to be assessed. This work focuses on two large Texas metropolitan areas: Dallas/Fort Worth, where NOx is emitted predominantly by mobile and area-wide sources; and Houston, which, like Dallas, has typical urban sources, but also contains large industrial point sources emitting significant amounts of NOx. Year-to-year and day-of- week changes in the satellite data are used to infer NOx emission trends from point and mobile sources and to evaluate the effectiveness of NOx controls on some of these sources.

  5. On the observed response of ozone to NOx and VOC reactivity reductions in San Joaquin Valley California 1995-present

    NASA Astrophysics Data System (ADS)

    Pusede, S. E.; Cohen, R. C.

    2012-09-01

    We describe the effects of nitrogen oxide (NOx) and organic reactivity reductions on the frequency of high ozone days in California's San Joaquin Valley. We use sixteen years of observations of ozone, nitrogen oxides, and temperature at sites upwind, within, and downwind of three cities to assess the probability of exceeding the California 8-h average ozone standard of 70.4 ppb at each location. The comprehensive data records in the region and the steep decreases in emissions over the last decade are sufficient to constrain the relative import of NOx and organic reactivity reductions on the frequency of violations. We show that high ozone has a large component that is due to local production, as the probability of exceeding the state standard is lowest for each city at the upwind site, increases in the city center, is highest at downwind locations, and then decreases at the receptor city to the south. We see that reductions in organic reactivity have been very effective in the central and northern regions of the San Joaquin but less so in the southern portion of the Valley. We find evidence for two distinct categories of reactivity sources: one source that has decreased and dominates at moderate temperatures, and a second source that dominates at high temperatures, particularly in the southern San Joaquin, and has not changed over the last twelve years. We show that NOx reductions are already effective or are poised to become so in the southern and central Valley, where violations are most frequent, as conditions in these regions have or are transitioning to NOx-limited chemistry when temperatures are hottest and high ozone most probable.

  6. On the observed response of ozone to NOx and VOC reactivity reductions in San Joaquin Valley California 1995-present

    NASA Astrophysics Data System (ADS)

    Pusede, S. E.; Cohen, R. C.

    2012-04-01

    We present a statistical approach to describe the effects of nitrogen oxide (NOx) and organic reactivity reductions on the frequency of high ozone days. We use sixteen years of observations of ozone, nitrogen oxides, and temperature at sites upwind, within, and downwind of three cities in California's San Joaquin Valley to assess the probability of exceeding of the California 8-h average ozone standard of 70.4 ppb at each location. We demonstrate that the comprehensive data records in the region and the steep decreases in emissions over the last decade are sufficient to constrain the relative import of NOx and organic reactivity reductions on the frequency of violations. We show that high ozone has a large component that is due to local production, as the probability of exceeding the state standard is lowest for each city at the upwind site, increases across the city center, is highest at downwind locations, and then decreases at the receptor city to the south. We see that reductions in organic reactivity have been very effective in the central and northern regions of the San Joaquin but not in the southern portion of the Valley. We find evidence for two distinct categories of reactivity sources: one source that has decreased and dominates at moderate temperatures, and a second source that dominates at high temperatures in the southern San Joaquin, which has not changed over the last twelve years. We show that NOx reductions are already effective or are poised to become so in the southern and central Valley, where violations are most frequent, as conditions in these regions have or are transitioning to NOx-limited chemistry when temperatures are hottest and high ozone most probable.

  7. Improving NO(x) cap-and-trade system with adjoint-based emission exchange rates.

    PubMed

    Mesbah, S Morteza; Hakami, Amir; Schott, Stephan

    2012-11-01

    Cap-and-trade programs have proven to be effective instruments for achieving environmental goals while incurring minimum cost. The nature of the pollutant, however, affects the design of these programs. NO(x), an ozone precursor, is a nonuniformly mixed pollutant with a short atmospheric lifetime. NO(x) cap-and-trade programs in the U.S. are successful in reducing total NO(x) emissions but may result in suboptimal environmental performance because location-specific ozone formation potentials are neglected. In this paper, the current NO(x) cap-and-trade system is contrasted to a hypothetical NO(x) trading policy with sensitivity-based exchange rates. Location-specific exchange rates, calculated through adjoint sensitivity analysis, are combined with constrained optimization for prediction of NO(x) emissions trading behavior and post-trade ozone concentrations. The current and proposed policies are examined in a case study for 218 coal-fired power plants that participated in the NO(x) Budget Trading Program in 2007. We find that better environmental performance at negligibly higher system-wide abatement cost can be achieved through inclusion of emission exchange rates. Exposure-based exchange rates result in better environmental performance than those based on concentrations. PMID:23050674

  8. NOx reduction Activity over Phosphate-supported Platinum Catalysts with Hydrogen under Oxygen-rich Condition

    NASA Astrophysics Data System (ADS)

    Itoh, M.; Takehara, M.; Saito, M.; Machida, K.

    2011-10-01

    The phosphate supported Pt catalysts (Pt/AlPO4, Pt/CePO4, Pt/CeP2O7, Pt/SnP2O7, Pt/TiP2O7, Pt/Zn3(PO4)2) were prepared by a conventional impregnation method to evaluate their selective catalytic reduction activity of NOx under excess oxygen condition. Among them, good NOx reduction activity was obtained on the Pt/AlPO4 catalyst. Specific adsorption species during the NOx reduction were checked by a diffuse reflectance infrared Fourier transform spectrum (DRIFTs) measurement to examine the reaction mechanism. Also NH3 temperature programmed desorption measurements were performed for all catalysts and their catalytic properties were discussed from the viewpoints of solid acidity.

  9. 500 MW demonstration of advanced wall-fired combustion techniques for the reduction of nitrogen oxide (NOx) emissions from coal-fired boilers. Public design report (preliminary and final)

    SciTech Connect

    1996-07-01

    This Public Design Report presents the design criteria of a DOE Innovative Clean Coal Technology (ICCT) project demonstrating advanced wall-fired combustion techniques for the reduction of NO{sub x} emissions from coal-fired boilers. The project is being conducted at Georgia Power Company`s Plant Hammond Unit 4 (500 MW) near Rome, Georgia. The technologies being demonstrated at this site include Foster Wheeler Energy Corporation`s advanced overfire air system and Controlled Flow/Split Flame low NO{sub x} burner. This report provides documentation on the design criteria used in the performance of this project as it pertains to the scope involved with the low NO{sub x} burners, advanced overfire systems, and digital control system.

  10. Anthropogenic NOx emissions alter the intrinsic water-use efficiency (WUEi) for Quercus cerris stands under Mediterranean climate conditions.

    PubMed

    Guerrieri, Rossella; Siegwolf, Rolf; Saurer, Matthias; Ripullone, Francesco; Mencuccini, Maurizio; Borghetti, Marco

    2010-09-01

    We investigated the effect of N deposition (Ndep) on intrinsic water-use efficiency (WUEi), the ratio of photosynthesis (A) to stomatal conductance (gs), for two Quercus cerris stands at different distances to an oil refinery in Southern Italy. We used delta13C in tree rings for assessing changes in WUEi; while the influence of climate and NOx emission was explored through delta18O and delta15N, respectively. Differences in WUEi between the two sites were significant, with trees exposed to different degrees of NOx emissions showing an abrupt increase with the onset of pollution. Assuming similar gs at the two sites, as inferred through delta18O, the higher N availability at the polluted site caused the shift of the A/gs ratio in favour of A. Overall, our result suggests that an increase of Ndep may enhance tree WUE under a scenario of reduction of precipitation predicted for Mediterranean area.

  11. Emission factors of air pollutants from CNG-gasoline bi-fuel vehicles: Part II. CO, HC and NOx.

    PubMed

    Huang, Xiaoyan; Wang, Yang; Xing, Zhenyu; Du, Ke

    2016-09-15

    The estimation of emission factors (EFs) is the basis of accurate emission inventory. However, the EFs of air pollutants for motor vehicles vary under different operating conditions, which will cause uncertainty in developing emission inventory. Natural gas (NG), considered as a "cleaner" fuel than gasoline, is increasingly being used to reduce combustion emissions. However, information is scarce about how much emission reduction can be achieved by motor vehicles burning NG (NGVs) under real road driving conditions, which is necessary for evaluating the environmental benefits for NGVs. Here, online, in situ measurements of the emissions from nine bi-fuel vehicles were conducted under different operating conditions on the real road. A comparative study was performed for the EFs of black carbon (BC), carbon monoxide (CO), hydrocarbons (HCs) and nitrogen oxides (NOx) for each operating condition when the vehicles using gasoline and compressed NG (CNG) as fuel. BC EFs were reported in part I. The part II in this paper series reports the influence of operating conditions and fuel types on the EFs of CO, HC and NOx. Fuel-based EFs of CO showed good correlations with speed when burning CNG and gasoline. The correlation between fuel-based HC EFs and speed was relatively weak whether burning CNG or gasoline. The fuel-based NOx EFs moderately correlated with speed when burning CNG, but weakly correlated with gasoline. As for HC, the mileage-based EFs of gasoline vehicles are 2.39-12.59 times higher than those of CNG vehicles. The mileage-based NOx EFs of CNG vehicles are slightly higher than those of gasoline vehicles. These results would facilitate a detailed analysis of the environmental benefits for replacing gasoline with CNG in light duty vehicles.

  12. Emission factors of air pollutants from CNG-gasoline bi-fuel vehicles: Part II. CO, HC and NOx.

    PubMed

    Huang, Xiaoyan; Wang, Yang; Xing, Zhenyu; Du, Ke

    2016-09-15

    The estimation of emission factors (EFs) is the basis of accurate emission inventory. However, the EFs of air pollutants for motor vehicles vary under different operating conditions, which will cause uncertainty in developing emission inventory. Natural gas (NG), considered as a "cleaner" fuel than gasoline, is increasingly being used to reduce combustion emissions. However, information is scarce about how much emission reduction can be achieved by motor vehicles burning NG (NGVs) under real road driving conditions, which is necessary for evaluating the environmental benefits for NGVs. Here, online, in situ measurements of the emissions from nine bi-fuel vehicles were conducted under different operating conditions on the real road. A comparative study was performed for the EFs of black carbon (BC), carbon monoxide (CO), hydrocarbons (HCs) and nitrogen oxides (NOx) for each operating condition when the vehicles using gasoline and compressed NG (CNG) as fuel. BC EFs were reported in part I. The part II in this paper series reports the influence of operating conditions and fuel types on the EFs of CO, HC and NOx. Fuel-based EFs of CO showed good correlations with speed when burning CNG and gasoline. The correlation between fuel-based HC EFs and speed was relatively weak whether burning CNG or gasoline. The fuel-based NOx EFs moderately correlated with speed when burning CNG, but weakly correlated with gasoline. As for HC, the mileage-based EFs of gasoline vehicles are 2.39-12.59 times higher than those of CNG vehicles. The mileage-based NOx EFs of CNG vehicles are slightly higher than those of gasoline vehicles. These results would facilitate a detailed analysis of the environmental benefits for replacing gasoline with CNG in light duty vehicles. PMID:27219504

  13. Characteristics of NOx Removal Combining Dielectric Barrier Discharge Plasma with Selective Catalytic Reduction by C3H6

    NASA Astrophysics Data System (ADS)

    Wang, Xing-Quan; Li, Yi; Chen, Wei; Lv, Guo-Hua; Huang, Jun; Zhu, Guo-Xian; Wang, Xiao-Qian; Zhang, Xian-Hui; Wang, Da-Cheng; Feng, Ke-Cheng; Yang, Si-Ze

    2010-08-01

    Characteristics of NOx removal combining dielectric barrier discharge (DBD) plasma with selective catalytic reduction (SCR) by C3H6 were investigated under the conditions of high NOx concentration and high space velocity at various temperatures. Experiment results show that there were no obvious removal of NOx and NO in the only C3H6-SCR system and only DBD system individually. But the high NOx removal rate was achieved in C3H6-SCR cooperating with DBD plasma system. Especially NOx removal rate can reach up to 88.5% at 150 °C simulating diesel engine exhaust temperature. It can be seen that when discharge comes into being, the catalystic activity was enhanced with discharge strengthened, so that the NOx was almost completely removed. In the course of NOx removal, DBD played an important role in oxidizing NO to NO2 and activating C3H6 and catalysts to reduce NOx.

  14. Evaluating NOx emission inventories for regulatory air quality modeling using satellite and air quality model data

    NASA Astrophysics Data System (ADS)

    Kemball-Cook, Susan; Yarwood, Greg; Johnson, Jeremiah; Dornblaser, Bright; Estes, Mark

    2015-09-01

    The purpose of this study was to assess the accuracy of NOx emissions in the Texas Commission on Environmental Quality's (TCEQ) State Implementation Plan (SIP) modeling inventories of the southeastern U.S. We used retrieved satellite tropospheric NO2 columns from the Ozone Monitoring Instrument (OMI) together with NO2 columns from the Comprehensive Air Quality Model with Extensions (CAMx) to make top-down NOx emissions estimates using the mass balance method. Two different top-down NOx emissions estimates were developed using the KNMI DOMINO v2.0 and NASA SP2 retrievals of OMI NO2 columns. Differences in the top-down NOx emissions estimates made with these two operational products derived from the same OMI radiance data were sufficiently large that they could not be used to constrain the TCEQ NOx emissions in the southeast. The fact that the two available operational NO2 column retrievals give such different top-down NOx emissions results is important because these retrievals are increasingly being used to diagnose air quality problems and to inform efforts to solve them. These results reflect the fact that NO2 column retrievals are a blend of measurements and modeled data and should be used with caution in analyses that will inform policy development. This study illustrates both benefits and challenges of using satellite NO2 data for air quality management applications. Comparison with OMI NO2 columns pointed the way toward improvements in the CAMx simulation of the upper troposphere, but further refinement of both regional air quality models and the NO2 column retrievals is needed before the mass balance and other emission inversion methods can be used to successfully constrain NOx emission inventories used in U.S. regulatory modeling.

  15. Lean NOx Reduction in Two Stages: Non-thermal Plasma Followed by Heterogeneous Catalysis

    SciTech Connect

    Tonkyn, Russell G.; Yoon, Ilsop S.; Barlow, Stephan E.; Panov, Alexander G.; Kolwaite, A; Balmer, Mari LOU.

    2000-10-16

    We present data in this paper showing that non-thermal plasma in combination with heterogeneous catalysis is a promising technique for the treatment of NOx in diesel exhaust. Using a commonly available zeolite catalyst, sodium Y, to treat synthetic diesel exhaust we report approximately 50% chemical reduction of NOx over a broad, representative temperature range. We have measured the overall efficiency as a function of the temperature and hydrocarbon concentration. The direct detection of N2 and N2O when the background gas is replaced by helium confirms that true chemical reduction is occurring.

  16. Method for the control of NOx emissions in long-range space travel.

    PubMed

    Xu, X H; Shi, Y; Liu, S H; Wang, H P; Chang, S G; Fisher, J W; Pisharody, S; Moran, M; Wignarajah, K

    2003-01-01

    The wheat straw, an inedible biomass that can be continuously produced in a space vehicle has been used to produce activated carbon for effective control of NOx emissions from the incineration of wastes. The optimal carbonization temperature of wheat straw was found to be around 600 degrees C when a burnoff of 67% was observed. The BET surface area of the activated carbon produced from the wheat straw reached as high as 300 m2/g. The presence of oxygen in flue gas is essential for effective adsorption of NO by activated carbon. On the contrary, water vapor inhibits the adsorption efficiency of NO. Consequently, water vapor in flue gas should be removed by drying agents before adsorption to ensure high NO adsorption efficiency. All of the NO in the flue gas was removed for more than 2 h by the activated carbons when 10% oxygen was present and the ratio of carbon weight to the flue gas flow rate (W/F) was 30 g min/L, with a contact time of 10.2 s. All of NO was reduced to N2 by the activated carbon at 450 degrees C with a W/F ratio of 15 g min/L and a contact time of 5.1 s. Reduction of the adsorbed NO also regenerated the activated carbon, and the regenerated activated carbon exhibited an improved NO adsorption efficiency. However, the reduction of the adsorbed NO resulted in a loss of carbon which was determined to be about 0.99% of the activated carbon per cycle of regeneration. The sufficiency of the amount of wheat straw in providing the activated carbon based on a six-person crew, such as the mission planned for Mars, has been determined. This novel approach for the control of NOx emissions is sustainable in a closed system such as the case in space travel. It is simple to operate and is functional under microgravity environment.

  17. Method for the control of NOx emissions in long-range space travel.

    PubMed

    Xu, X H; Shi, Y; Liu, S H; Wang, H P; Chang, S G; Fisher, J W; Pisharody, S; Moran, M; Wignarajah, K

    2003-01-01

    The wheat straw, an inedible biomass that can be continuously produced in a space vehicle has been used to produce activated carbon for effective control of NOx emissions from the incineration of wastes. The optimal carbonization temperature of wheat straw was found to be around 600 degrees C when a burnoff of 67% was observed. The BET surface area of the activated carbon produced from the wheat straw reached as high as 300 m2/g. The presence of oxygen in flue gas is essential for effective adsorption of NO by activated carbon. On the contrary, water vapor inhibits the adsorption efficiency of NO. Consequently, water vapor in flue gas should be removed by drying agents before adsorption to ensure high NO adsorption efficiency. All of the NO in the flue gas was removed for more than 2 h by the activated carbons when 10% oxygen was present and the ratio of carbon weight to the flue gas flow rate (W/F) was 30 g min/L, with a contact time of 10.2 s. All of NO was reduced to N2 by the activated carbon at 450 degrees C with a W/F ratio of 15 g min/L and a contact time of 5.1 s. Reduction of the adsorbed NO also regenerated the activated carbon, and the regenerated activated carbon exhibited an improved NO adsorption efficiency. However, the reduction of the adsorbed NO resulted in a loss of carbon which was determined to be about 0.99% of the activated carbon per cycle of regeneration. The sufficiency of the amount of wheat straw in providing the activated carbon based on a six-person crew, such as the mission planned for Mars, has been determined. This novel approach for the control of NOx emissions is sustainable in a closed system such as the case in space travel. It is simple to operate and is functional under microgravity environment. PMID:14672086

  18. Method for the control of NOx emissions in long-range space travel

    NASA Technical Reports Server (NTRS)

    Xu, X. H.; Shi, Y.; Liu, S. H.; Wang, H. P.; Chang, S. G.; Fisher, J. W.; Pisharody, S.; Moran, M.; Wignarajah, K.

    2003-01-01

    The wheat straw, an inedible biomass that can be continuously produced in a space vehicle has been used to produce activated carbon for effective control of NOx emissions from the incineration of wastes. The optimal carbonization temperature of wheat straw was found to be around 600 degrees C when a burnoff of 67% was observed. The BET surface area of the activated carbon produced from the wheat straw reached as high as 300 m2/g. The presence of oxygen in flue gas is essential for effective adsorption of NO by activated carbon. On the contrary, water vapor inhibits the adsorption efficiency of NO. Consequently, water vapor in flue gas should be removed by drying agents before adsorption to ensure high NO adsorption efficiency. All of the NO in the flue gas was removed for more than 2 h by the activated carbons when 10% oxygen was present and the ratio of carbon weight to the flue gas flow rate (W/F) was 30 g min/L, with a contact time of 10.2 s. All of NO was reduced to N2 by the activated carbon at 450 degrees C with a W/F ratio of 15 g min/L and a contact time of 5.1 s. Reduction of the adsorbed NO also regenerated the activated carbon, and the regenerated activated carbon exhibited an improved NO adsorption efficiency. However, the reduction of the adsorbed NO resulted in a loss of carbon which was determined to be about 0.99% of the activated carbon per cycle of regeneration. The sufficiency of the amount of wheat straw in providing the activated carbon based on a six-person crew, such as the mission planned for Mars, has been determined. This novel approach for the control of NOx emissions is sustainable in a closed system such as the case in space travel. It is simple to operate and is functional under microgravity environment.

  19. Impact of Aircraft Emissions on NO(x) in the Lowermost Stratosphere at Northern Midlatitudes

    NASA Technical Reports Server (NTRS)

    Kondo, Y.; Koike, M.; Ikeda, H.; Anderson, B. E.; Brunke, K. E.; Zhao, Y.; Kita, K.; Sugita, T.; Singh, H. B.; Liu, S. C.

    1999-01-01

    Airborne measurements of NO(x) total reactive nitrogen (NO(y)), O3 and condensation nuclei (CN) were made within air traffic corridors over the U.S. and North Atlantic regions (35-60 deg N) in the fall of 1997. NO(x) and NO(y) data obtained in the lowermost stratosphere (LS) were examined using the calculated increase in NO(y) ((delta)NO(y)) along five-day back trajectories as a parameter to identify possible effects of aircraft on reactive nitrogen. It is very likely that aircraft emissions had a significant impact on the NO(x) levels in the LS inasmuch as the NO(s), mixing ratios at 8.5-12 km were significantly correlated with the independent parameters of aircraft emissions, i.e., (delta)NO(y) levels and CN values. In order to estimate quantitatively the impact of aircraft emissions on NO(x), and CN, the background levels of CN and NO(x) at O3 = 100-200 ppbv were derived from the correlations of these quantities with (delta)NO(y)). On average, the aircraft emissions are estimated to have increased the NO(x) and CN values by 130 pptv and 400 STP,cc, respectively, which corresponds to 70 -/+ 30 % and 30 -/+ 20 % of the observed median values.

  20. Estimated emission reductions from California's enhanced Smog Check program.

    PubMed

    Singer, Brett C; Wenzel, Thomas P

    2003-06-01

    The U.S. Environmental Protection Agency requires that states evaluate the effectiveness of their vehicle emissions inspection and maintenance (I/M) programs. This study demonstrates an evaluation approach that estimates mass emission reductions over time and includes the effect of I/M on vehicle deterioration. It includes a quantitative assessment of benefits from pre-inspection maintenance and repairs and accounts for the selection bias effect that occurs when intermittent high emitters are tested. We report estimates of one-cycle emission benefits of California's Enhanced Smog Check program, ca. 1999. Program benefits equivalent to metric tons per day of prevented emissions were calculated with a "bottom-up" approach that combined average per vehicle reductions in mass emission rates (g/gal) with average per vehicle activity, resolved by model year. Accelerated simulation mode test data from the statewide vehicle information database (VID) and from roadside Smog Check testing were used to determine 2-yr emission profiles of vehicles passing through Smog Check and infer emission profiles that would occur without Smog Check. The number of vehicles participating in Smog Check was also determined from the VID. We estimate that in 1999 Smog Check reduced tailpipe emissions of HC, CO, and NO(x) by 97, 1690, and 81 t/d, respectively. These correspond to 26, 34, and 14% of the HC, CO, and NO(x) that would have been emitted by vehicles in the absence of Smog Check. These estimates are highly sensitive to assumptions about vehicle deterioration in the absence of Smog Check. Considering the estimated uncertainty in these assumptions yields a range for calculated benefits: 46-128 t/d of HC, 860-2200 t/d of CO, and 60-91 t/d of NO(x). Repair of vehicles that failed an initial, official Smog Check appears to be the most important mechanism of emission reductions, but pre-inspection maintenance and repair also contributed substantially. Benefits from removal of nonpassing

  1. In2O3/Al2O3 Catalysts for NOx Reduction in Lean Condition

    SciTech Connect

    Park, Paul W.; Ragle, Christie; Boyer, Carrie S.; Balmer, M Lou; Engelhard, Mark H. ); McCready, David E. )

    2002-01-01

    The lean NOx performance and catalytic properties of In2O3/Al2O3 catalysts were investigated. High lean NOx activity was observed when propene was used as a reductant in the presence of 9% O2 and 7% H2O at a space velocity of 30,000h-1. The optimum lean NOx activity of In2O3/Al2O3 catalysts was observed at a loading of 2.5 wt.% indium on -Al2O3 which was prepared by a sol-gel technique (230 m2/g). When propane was used as a reductant, the In2O3/Al2O3 catalyst did not promote NOx reduction compared to the alumina substrate. X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and temperature programmed reduction (TPR) have been used to characterize a series of In2O3/Al2O3 catalysts to better understand the surface structure of indium oxide species on the alumina support. The XRD data indicated that crystalline In2O3 was present at In2O3 loadings > 5wt.% and the quantity of the crystalline phase increased as a function of indium loading. XPS results suggested that indium oxide existed as a well-dispersed phase up to 10wt.% indium. The well dispersed or reducible indium oxide species below 400 C in TPR experiments were assigned as the sites which activate propene to oxygenated hydrocarbons such as acetaldehyde and acrolein. Alumina sites readily utilize the oxygenated hydrocarbons to reduce NOx. Dual-function mechanism was proposed to explain NOx reduction over In2O3/Al2O3 catalysts.

  2. NOx Emissions from Large Point Sources: Variability in Ozone Production, Resulting Health Damages and Economic Costs

    NASA Astrophysics Data System (ADS)

    Mauzerall, D. L.; Sultan, B.; Kim, N.; Bradford, D.

    2004-12-01

    We present a proof-of-concept analysis of the measurement of the health damage of ozone (O3) produced from nitrogen oxides (NOx = NO + NO2) emitted by individual large point sources in the eastern United States. We use a regional atmospheric model of the eastern United States, the Comprehensive Air Quality Model with Extensions (CAMx), to quantify the variable impact that a fixed quantity of NOx emitted from individual sources can have on the downwind concentration of surface O3, depending on temperature and local biogenic hydrocarbon emissions. We also examine the dependence of resulting ozone-related health damages on the size of the exposed population. The investigation is relevant to the increasingly widely used "cap and trade" approach to NOx regulation, which presumes that shifts of emissions over time and space, holding the total fixed over the course of the summer O3 season, will have minimal effect on the environmental outcome. By contrast, we show that a shift of a unit of NOx emissions from one place or time to another could result in large changes in the health effects due to ozone formation and exposure. We indicate how the type of modeling carried out here might be used to attach externality-correcting prices to emissions. Charging emitters fees that are commensurate with the damage caused by their NOx emissions would create an incentive for emitters to reduce emissions at times and in locations where they cause the largest damage.

  3. A simplified reaction mechanism for prediction of NO(x) emissions in the combustion of hydrocarbons

    NASA Technical Reports Server (NTRS)

    Kundu, K. P.; Deur, J. M.

    1992-01-01

    A simplified reaction mechanism is developed for the prediction of NO(x) in hydrocarbon combustion. The mechanism uses fewer reacting species and reaction steps than the detailed mechanisms available in the literature and therefore takes less computer time when used in CFD calculations. The mechanism has been used to calculate NO(x) emissions in the combustion of propane. With slight modifications, the same mechanism can be used to calculate NO(x) in the combustion of other hydrocarbons. Results obtained with the simplified reaction are compared with experimental results and results obtained with a detailed kinetic mechanism.

  4. Limitations of ozone data assimilation with adjustment of NOx emissions: mixed effects on NO2 forecast over Beijing and surrounding areas

    NASA Astrophysics Data System (ADS)

    Tang, X.; Zhu, J.; Wang, Z. F.; Gbaguidi, A.; Lin, C. Y.; Xin, J. Y.; Song, T.; Hu, B.

    2015-12-01

    This study investigates a cross-variable ozone data assimilation (DA) method based on an ensemble Kalman filter (EnKF) that has been validated as an efficient approach for improving ozone forecasts. The main purpose is to delve into the impacts of the cross-variable adjustment of nitrogen oxides (NOx) emissions on the nitrogen dioxide (NO2) forecasts over Beijing and surrounding regions during the 2008 Beijing Olympic Games. A mixed effect on the NO2 forecasts was observed during the application of the cross-variable assimilation approach in real-data assimilation (RDA) experiments. The method improved the NO2 forecast over almost half of the urban sites with reductions of the root mean square errors (RMSEs) by 15-36 % in contrast to big increases of the RMSEs over other urban stations by 56-239 %. Over the urban stations with negative DA impacts, improvement of the NO2 forecasts with 7 % reduction of the RMSEs was noticed during the night and the morning vs. significant deterioration of the forecasts during daytime with 190 % increase of the RMSEs, suggesting the negative DA impacts mainly occurred during daytime. Ideal data assimilation (IDA) experiments with a box model and the same cross-variable assimilation method, as a further investigation, confirmed the mixed effects found in the RDA experiments. An improvement of the NOx emission estimation was obtained from the cross-variable assimilation under relatively small errors in the prior estimation of NOx emissions during daytime, while deterioration of the NOx emission estimation was found under large biases in the prior estimation of NOx emissions during daytime. However, the cross-variable assimilation improved the NOx emission estimations during the night and the morning even with large biases in the prior estimations. The mixed effects observed in the cross-variable assimilation, i.e., positive DA impacts on NO2 forecast over some urban sites, negative DA impacts over the other urban sites and weak DA

  5. Simultaneous NOx and hydrocarbon emissions control for lean-burn engines using low-temperature solid oxide fuel cell at open circuit.

    PubMed

    Huang, Ta-Jen; Hsu, Sheng-Hsiang; Wu, Chung-Ying

    2012-02-21

    The high fuel efficiency of lean-burn engines is associated with high temperature and excess oxygen during combustion and thus is associated with high-concentration NO(x) emission. This work reveals that very high concentration of NO(x) in the exhaust can be reduced and hydrocarbons (HCs) can be simultaneously oxidized using a low-temperature solid oxide fuel cell (SOFC). An SOFC unit is constructed with Ni-YSZ as the anode, YSZ as the electrolyte, and La(0.6)Sr(0.4)CoO(3) (LSC)-Ce(0.9)Gd(0.1)O(1.95) as the cathode, with or without adding vanadium to LSC. SOFC operation at 450 °C and open circuit can effectively treat NO(x) over the cathode at a very high concentration in the simulated exhaust. Higher NO(x) concentration up to 5000 ppm can result in a larger NO(x) to N(2) rate. Moreover, a higher oxygen concentration promotes NO conversion. Complete oxidation of HCs can be achieved by adding silver to the LSC current collecting layer. The SOFC-based emissions control system can treat NO(x) and HCs simultaneously, and can be operated without consuming the anode fuel (a reductant) at near the engine exhaust temperature to eliminate the need for reductant refilling and extra heating.

  6. The effect of functional forms of nitrogen on fuel-NOx emissions.

    PubMed

    Zhang, Linghui; Su, Dagen; Zhong, Mingfeng

    2015-01-01

    This work explores the effects of different nitrogen functional forms on fuel-NOx emissions at 900 °C. The majority of tests are performed with an excess air coefficient of 1.4. Fuel-NOx is detected by measuring N-(1-naphthyl) ethylenediamine dihydrochloride (C₁₂H₁₆Cl₂N₂) via spectrophotometry. The different functional forms of nitrogen in the raw materials are identified by using X-ray photoelectron spectroscopy (XPS). A reliable density functional theory (DFT) method at the B3LYP/6-311++G** level is employed to investigate the reaction pathways of all functional forms of nitrogen during combustion. The results indicate that the functional forms of nitrogen influence the formation of nitrogen oxides. While under the same experimental conditions, fuel-NOx emissions increase by using less activation energy and nitrogen-containing groups with poor thermal stability. It is determined that fuel-NOx emissions vary in the following order: glycine > pyrrole > pyridine > methylenedi-p-phenylene diisocyanate (MDI). Glycine is the chain structure of amino acids in waste-leather and has low activation energy and poor thermal stability. With these properties, it is noted that glycine produces the most fuel-NOx in all of the raw materials studied. More pyrrole than pyridine in coal lead to high yields of fuel-NOx. The lowest yields of fuel-NO x are obtained using polyurethanes in waste-PU.

  7. Shifting primary energy source and NOx emission location with plug-in hybrid vehicles

    NASA Astrophysics Data System (ADS)

    Karman, Deniz

    2011-06-01

    Plug-in hybrid vehicles (PHEVs) present an interesting technological opportunity for using non-fossil primary energy in light duty passenger vehicles, with the associated potential for reducing air pollutant and greenhouse gas emissions, to the extent that the electric power grid is fed by non-fossil sources. This perspective, accompanying the article by Thompson et al (2011) in this issue, will touch on two other studies that are directly related: the Argonne study (Elgowainy et al 2010) and a PhD thesis from Utrecht (van Vliet 2010). Thompson et al (2011) have examined air quality effects in a case where the grid is predominantly fossil fed. They estimate a reduction of 7.42 tons/day of NOx from motor vehicles as a result of substituting electric VMTs for 20% of the light duty gasoline vehicle miles traveled. To estimate the impact of this reduction on air quality they also consider the increases in NOx emissions due to the increased load on electricity generating units. The NOx emission increases are estimated as 4.0, 5.5 and 6.3 tons for the Convenience, Battery and Night charging scenarios respectively. The net reductions are thus in the 1.1-3.4 tons/day range. The air quality modelling results presented show that the air quality impact from a ground-level ozone perspective is favorable overall, and while the effect is stronger in some localities, the difference between the three scenarios is small. This is quite significant and suggests that localization of the NOx emissions to point sources has a more pronounced effect than the absolute reductions achieved. Furthermore it demonstrates that localization of NOx emissions to electricity generating units by using PHEVs in vehicle traffic has beneficial effects for air quality not only by minimizing direct human exposure to motor vehicle emissions, but also due to reduced exposure to secondary pollutants (i.e. ozone). In an electric power grid with a smaller share of fossil fired generating units, the beneficial

  8. Long-term NOx trends over large cities in the United States during the great recession: Comparison of satellite retrievals, ground observations, and emission inventories

    NASA Astrophysics Data System (ADS)

    Tong, Daniel Q.; Lamsal, Lok; Pan, Li; Ding, Charles; Kim, Hyuncheol; Lee, Pius; Chai, Tianfeng; Pickering, Kenneth E.; Stajner, Ivanka

    2015-04-01

    National emission inventories (NEIs) take years to assemble, but they can become outdated quickly, especially for time-sensitive applications such as air quality forecasting. This study compares multi-year NOx trends derived from satellite and ground observations and uses these data to evaluate the updates of NOx emission data by the US National Air Quality Forecast Capability (NAQFC) for next-day ozone prediction during the 2008 Global Economic Recession. Over the eight large US cities examined here, both the Ozone Monitoring Instrument (OMI) and the Air Quality System (AQS) detect substantial downward trends from 2005 to 2012, with a seven-year total of -35% according to OMI and -38% according to AQS. The NOx emission projection adopted by NAQFC tends to be in the right direction, but at a slower reduction rate (-25% from 2005 to 2012), due likely to the unaccounted effects of the 2008 economic recession. Both OMI and AQS datasets display distinct emission reduction rates before, during, and after the 2008 global recession in some cities, but the detailed changing rates are not consistent across the OMI and AQS data. Our findings demonstrate the feasibility of using space and ground observations to evaluate major updates of emission inventories objectively. The combination of satellite, ground observations, and in-situ measurements (such as emission monitoring in power plants) is likely to provide more reliable estimates of NOx emission and its trend, which is an issue of increasing importance as many urban areas in the US are transitioning to NOx-sensitive chemical regimes by continuous emission reductions.

  9. Simulation of NOx emission in circulating fluidized beds burning low-grade fuels

    SciTech Connect

    Afsin Gungor

    2009-05-15

    Nitrogen oxides are a major environmental pollutant resulting from combustion. This paper presents a modeling study of pollutant NOx emission resulting from low-grade fuel combustion in a circulating fluidized bed. The simulation model accounts for the axial and radial distribution of NOx emission in a circulating fluidized bed (CFB). The model results are compared with and validated against experimental data both for small-size and industrial-size CFBs that use different types of low-grade fuels given in the literature. The present study proves that CFB combustion demonstrated by both experimental data and model predictions produces low and acceptable levels of NOx emissions resulting from the combustion of low-grade fuels. Developed model can also investigate the effects of different operational parameters on overall NOx emission. As a result of this investigation, both experimental data and model predictions show that NOx emission increases with the bed temperature but decreases with excess air if other parameters are kept unchanged. 37 refs., 5 figs., 5 tabs.

  10. Evaluating BC and NOx emission inventories for the Paris region from MEGAPOLI aircraft measurements

    NASA Astrophysics Data System (ADS)

    Petetin, H.; Beekmann, M.; Colomb, A.; Denier van der Gon, H. A. C.; Dupont, J.-C.; Honoré, C.; Michoud, V.; Morille, Y.; Perrussel, O.; Schwarzenboeck, A.; Sciare, J.; Wiedensohler, A.; Zhang, Q. J.

    2015-09-01

    High uncertainties affect black carbon (BC) emissions, and, despite its important impact on air pollution and climate, very few BC emissions evaluations are found in the literature. This paper presents a novel approach, based on airborne measurements across the Paris, France, plume, developed in order to evaluate BC and NOx emissions at the scale of a whole agglomeration. The methodology consists in integrating, for each transect, across the plume observed and simulated concentrations above background. This allows for several error sources (e.g., representativeness, chemistry, plume lateral dispersion) to be minimized in the model used. The procedure is applied with the CHIMERE chemistry-transport model to three inventories - the EMEP inventory and the so-called TNO and TNO-MP inventories - over the month of July 2009. Various systematic uncertainty sources both in the model (e.g., boundary layer height, vertical mixing, deposition) and in observations (e.g., BC nature) are discussed and quantified, notably through sensitivity tests. Large uncertainty values are determined in our results, which limits the usefulness of the method to rather strongly erroneous emission inventories. A statistically significant (but moderate) overestimation is obtained for the TNO BC emissions and the EMEP and TNO-MP NOx emissions, as well as for the BC / NOx emission ratio in TNO-MP. The benefit of the airborne approach is discussed through a comparison with the BC / NOx ratio at a ground site in Paris, which additionally suggests a spatially heterogeneous error in BC emissions over the agglomeration.

  11. Differences in satellite-derived NOx emission factors between Eurasian and North American boreal forest fires

    NASA Astrophysics Data System (ADS)

    Schreier, S. F.; Richter, A.; Schepaschenko, D.; Shvidenko, A.; Hilboll, A.; Burrows, J. P.

    2015-11-01

    Current fire emission inventories apply universal emission factors (EFs) for the calculation of NOx emissions over large biomes such as boreal forest. However, recent satellite-based studies over tropical and subtropical regions have indicated spatio-temporal variations in EFs within specific biomes. In this study, satellite measurements of tropospheric NO2 vertical columns (TVC NO2) from the GOME-2 instrument and fire radiative power (FRP) from MODIS are used for the estimation of fire emission rates (FERs) of NOx over Eurasian and North American boreal forests. The retrieval of TVC NO2 is based on a stratospheric correction using simulated stratospheric NO2 instead of applying the reference sector method, which was used in a previous study. The model approach is more suitable for boreal latitudes. TVC NO2 and FRP are spatially aggregated to a 1° × 1° horizontal resolution and temporally averaged to monthly values. The conversion of the satellite-derived tropospheric NO2 columns into production rates of NOx from fire (Pf) is based on the NO2/NOx ratio as obtained from the MACC reanalysis data set and an assumed lifetime of NOx. A global land cover map is used to define boreal forests across these two regions in order to evaluate the FERs of NOx for this biome. The FERs of NOx, which are derived from the gradients of the linear relationship between Pf and FRP, are more than 30% lower for North American than for Eurasian boreal forest fires. We speculate that these discrepancies are mainly related to the variable nitrogen content in plant tissues, which is higher in deciduous forests dominating large parts in Eurasia. In order to compare the obtained values with EFs found in the literature, the FERs are converted into EFs. The satellite-based EFs of NOx are estimated at 0.83 and 0.61 g kg-1 for Eurasian and North American boreal forests, respectively, which is in good agreement with the value found in a recent emission factor compilation. However, recent fire

  12. Reduction of aircraft gas turbine engine pollutant emissions

    NASA Technical Reports Server (NTRS)

    Diehl, L. A.

    1978-01-01

    To accomplish simultaneous reduction of unburned hydrocarbons, carbon monoxide, and oxides of nitrogen, required major modifications to the combustor. The modification most commonly used was a staged combustion technique. While these designs are more complicated than production combustors, no insurmountable operational difficulties were encountered in either high pressure rig or engine tests which could not be resolved with additional normal development. The emission reduction results indicate that reductions in unburned hydrocarbons were sufficient to satisfy both near and far-termed EPA requirements. Although substantial reductions were observed, the success in achieving the CO and NOx standards was mixed and depended heavily on the engine/engine cycle on which it was employed. Technology for near term CO reduction was satisfactory or marginally satisfactory. Considerable doubt exists if this technology will satisfy all far-term requirements.

  13. 40 CFR 51.122 - Emissions reporting requirements for SIP revisions relating to budgets for NOX emissions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... reporting requirements of 40 CFR part 75, then the state need not provide an every-year cycle report to EPA... SIP revisions relating to budgets for NOX emissions. 51.122 Section 51.122 Protection of Environment... OF IMPLEMENTATION PLANS Control Strategy § 51.122 Emissions reporting requirements for SIP...

  14. 40 CFR 51.122 - Emissions reporting requirements for SIP revisions relating to budgets for NOX emissions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... reporting requirements of 40 CFR part 75, then the state need not provide an every-year cycle report to EPA... SIP revisions relating to budgets for NOX emissions. 51.122 Section 51.122 Protection of Environment... OF IMPLEMENTATION PLANS Control Strategy § 51.122 Emissions reporting requirements for SIP...

  15. 40 CFR 75.19 - Optional SO2, NOX, and CO2 emissions calculation for low mass emissions (LME) units.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... rates in Table LM-2 of this section are inappropriately high for the unit, the owner or operator may use... interval, the owner or operator shall either report the appropriate default NOX emission rate from Table LM... example, use the default emission rates in Tables LM-1, LM-2, and LM-3 of this section or use the...

  16. NOx storage and reduction in model lean NOx trap catalysts studied by in situ DRIFTS

    SciTech Connect

    Ji, Yaying; Toops, Todd J; Pihl, Josh A; Crocker, Mark

    2009-01-01

    NO{sub x} storage and reduction on a model Pt/BaO/Al{sub 2}O{sub 3} catalyst was studied by means of in situ DRIFTS measurements. To examine the effect of ceria addition, experiments were also conducted using Pt/BaO/Al{sub 2}O{sub 3} to which Pt/CeO{sub 2} was added as a physical mixture in a 74:26 weight ratio. For the former catalyst, DRIFT spectra acquired during NO/O{sub 2} and NO{sub 2}/O{sub 2} storage indicated the formation of nitrite at 200 C during the initial stages of adsorption, while increasing the adsorption temperature appeared to facilitate the oxidation of nitrite to nitrate. The ceria-containing catalyst afforded similar DRIFT spectra under these conditions, although the presence of cerium nitrates was observed at 200 and 300 C, consistent with NO{sub x} storage on the ceria phase. DRIFT spectra acquired during NO{sub x} reduction in CO and CO/H{sub 2} showed that Ba nitrate species remained on the surface of both catalysts at 450 C, whereas the use of H{sub 2}-only resulted in complete removal of stored NO{sub x}. The observation of Ba carbonates when CO was present suggests that the inferior reduction efficiency of CO may arise from the formation of a crust of BaCO{sub 3} on the Ba phase, which inhibits further NO{sub x} reduction. DRIFT spectra acquired during lean-rich cycling (6.5 min lean, 1.0 min rich) with CO/H{sub 2} as the rich phase reductants revealed that a significant concentration of nitrates remained on the catalysts at the end of the rich phase. This implies that a large fraction of nitrate is not decomposed during cycling and thus cannot participate in NO{sub x} abatement through storage and regeneration.

  17. Investigation of NOx Reduction by Low Temperature Oxidation Using Ozone Produced by Dielectric Barrier Discharge

    NASA Astrophysics Data System (ADS)

    Stamate, Eugen; Irimiea, Cornelia; Salewski, Mirko

    2013-05-01

    NOx reduction by low temperature oxidation using ozone produced by a dielectric barrier discharge generator is investigated for different process parameters in a 6 m long reactor in serpentine arrangement using synthetic dry flue gas with NOx levels below 500 ppm, flows up to 50 slm and temperatures up to 80 °C. The role of different mixing schemes and the impact of a steep temperature gradient are also taken into consideration. The process chemistry is monitored by Fourier transform infrared spectroscopy, chemiluminescence and absorption spectroscopy. The kinetic mechanism during the mixing in a cross flow configuration is investigated using three-dimensional simulations.

  18. Spatially resolved flux measurements of NOx from London suggest significantly higher emissions than predicted by inventories.

    PubMed

    Vaughan, Adam R; Lee, James D; Misztal, Pawel K; Metzger, Stefan; Shaw, Marvin D; Lewis, Alastair C; Purvis, Ruth M; Carslaw, David C; Goldstein, Allen H; Hewitt, C Nicholas; Davison, Brian; Beevers, Sean D; Karl, Thomas G

    2016-07-18

    To date, direct validation of city-wide emissions inventories for air pollutants has been difficult or impossible. However, recent technological innovations now allow direct measurement of pollutant fluxes from cities, for comparison with emissions inventories, which are themselves commonly used for prediction of current and future air quality and to help guide abatement strategies. Fluxes of NOx were measured using the eddy-covariance technique from an aircraft flying at low altitude over London. The highest fluxes were observed over central London, with lower fluxes measured in suburban areas. A footprint model was used to estimate the spatial area from which the measured emissions occurred. This allowed comparison of the flux measurements to the UK's National Atmospheric Emissions Inventory (NAEI) for NOx, with scaling factors used to account for the actual time of day, day of week and month of year of the measurement. The comparison suggests significant underestimation of NOx emissions in London by the NAEI, mainly due to its under-representation of real world road traffic emissions. A comparison was also carried out with an enhanced version of the inventory using real world driving emission factors and road measurement data taken from the London Atmospheric Emissions Inventory (LAEI). The measurement to inventory agreement was substantially improved using the enhanced version, showing the importance of fully accounting for road traffic, which is the dominant NOx emission source in London. In central London there was still an underestimation by the inventory of 30-40% compared with flux measurements, suggesting significant improvements are still required in the NOx emissions inventory.

  19. Spatially Resolved Emissions of NOx and VOCs and Comparison to Inventories.

    NASA Astrophysics Data System (ADS)

    Vaughan, A. R.; Lee, J. D.; Lewis, A. C.; Shaw, M.; Purvis, R.; Carslaw, D.; Hewitt, C. N.; Misztal, P. K.; Metzger, S.; Beevers, S.; Goldstein, A. H.; Karl, T.; Davison, B.

    2015-12-01

    Recent trends in ambient concentrations of NOx in the UK (and other European countries) have shown a general decrease over the period 1990 to 2002, followed by largely static concentrations from 2004 - present. This is not in line with the decreases predicted based on bottom up emission inventories and has lead to widespread non-compliance with EU Air Quality Directives. We present a method to quantify the geographic variability of emission of NOx and selected VOCs at a city scale (London) using an aircraft platform. High frequency observations of NOx and VOCs (10 Hz and 2 Hz, respectively) were made using low altitude flights across London and combined with 20 Hz micro-meteorological data to provide an emission flux using the aircraft eddy covariance technique. A continuous wavelet transformation was used to produce instantaneous fluxes along the flight transect and a parameterisation of a backward Lagrangian model used to calculate the flux footprint, attributing emission rates to specific areas in Greater London (see figure). The observed flux was compared to the UK National Atmospheric Emission Inventory (NAEI), which takes a "bottom up" approach to calculating emissions, involving estimates from different source sectors to produce yearly emission estimates. These were then modified using factors specific to each source to reflect the actual month, day and time of the flight, to provide a more meaningful comparison to the observation. A significant underestimation in the inventory NOx was observed ranging from 150-200% in outer London, to 300% in the central area. Potential reasons for this are discussed, including the poor treatment of real world emissions of NOx from diesel vehicles in the inventory. We also compare measurements to the London Atmospheric Emissions Inventory (LAEI), which provides a more explicit treatment of the traffic emissions specific to London and which shows better agreement with the measurements.

  20. Spatially resolved flux measurements of NOx from London suggest significantly higher emissions than predicted by inventories.

    PubMed

    Vaughan, Adam R; Lee, James D; Misztal, Pawel K; Metzger, Stefan; Shaw, Marvin D; Lewis, Alastair C; Purvis, Ruth M; Carslaw, David C; Goldstein, Allen H; Hewitt, C Nicholas; Davison, Brian; Beevers, Sean D; Karl, Thomas G

    2016-07-18

    To date, direct validation of city-wide emissions inventories for air pollutants has been difficult or impossible. However, recent technological innovations now allow direct measurement of pollutant fluxes from cities, for comparison with emissions inventories, which are themselves commonly used for prediction of current and future air quality and to help guide abatement strategies. Fluxes of NOx were measured using the eddy-covariance technique from an aircraft flying at low altitude over London. The highest fluxes were observed over central London, with lower fluxes measured in suburban areas. A footprint model was used to estimate the spatial area from which the measured emissions occurred. This allowed comparison of the flux measurements to the UK's National Atmospheric Emissions Inventory (NAEI) for NOx, with scaling factors used to account for the actual time of day, day of week and month of year of the measurement. The comparison suggests significant underestimation of NOx emissions in London by the NAEI, mainly due to its under-representation of real world road traffic emissions. A comparison was also carried out with an enhanced version of the inventory using real world driving emission factors and road measurement data taken from the London Atmospheric Emissions Inventory (LAEI). The measurement to inventory agreement was substantially improved using the enhanced version, showing the importance of fully accounting for road traffic, which is the dominant NOx emission source in London. In central London there was still an underestimation by the inventory of 30-40% compared with flux measurements, suggesting significant improvements are still required in the NOx emissions inventory. PMID:27098421

  1. JV Task-Long-Kiln NOx Reduction Study

    SciTech Connect

    Bruce Folkedahl; Joshua Strege; Darren Schmidt; Lingbu Kong

    2008-07-01

    Field sampling was conducted by the Energy & Environmental Research Center at two Lafarge North America cement kiln locations in Canada. Emissions including SO{sub x}, NO{sub x}, and particulate were measured and reported at various locations throughout the kilns. At each site data were collected on two kilns during field sampling. However, only Kiln 1 at the Ravena site was utilized for modeling efforts. Experimental work was then conducted to estimate the effectiveness of various NO{sub x} control techniques on limiting both NO{sub x} and SO{sub x} emissions in cement kiln exhaust. Theory-based models were constructed to estimate both NO{sub x} and SO{sub x} emissions from cement kilns. These models were then applied to estimating the impact of various NO{sub x} control strategies on kiln exhaust emissions. The sulfur model constructed as part of this work was successful at predicting SO{sub 2} emissions and sulfur capture in the Alpena kiln. This model is designed to run as a postprocessing step that uses the output of a NO{sub x} model as input. With an accurate NO{sub x} model, the sulfur model may prove to be a valuable tool in estimating the impact of kiln modifications on sulfur emissions. The NO{sub x} model was also applied to model several operating scenarios on three of Lafarge's kilns: Alpena 20/21, Alpena 22/23, and Ravena 1. The predictions of the flue gas temperature at the kiln feed end, the kiln shell heat loss, the quality of clinker, and the excess O{sub 2} in the flue gas are consistent with the audit data. The developed simulation tool in this project has proven to be an effective way to investigate the NO{sub x} emissions, to optimize kiln performance, and to assess changes in operating condition on kiln performance.

  2. Heavy-Duty Emissions Control: Plasma-Facilitated vs Reformer-Assisted Lean NOx Catalysis

    SciTech Connect

    Aardahl, C; Rozmiarek, R; Rappe, K; Mendoza, D Park, P

    2003-08-24

    Progress has been made in the control of combustion processes to limit the formation of environmentally harmful species, but lean burn vehicles, such as those powered by diesel engines used for the majority of commercial trucking and off-road applications, remain a major source of nitrogen oxides (NOx) and particulate matter (PM) emissions. Tighter control of the combustion process coupled with exhaust gas recirculation has brought emissions in line with 2004 targets worldwide. Additional modifications to the engine control system, somewhat limited NOx control, and PM filters will likely allow the 2007 limits to be met for the on-highway regulations for heavy-duty engines in the United States. Concern arises when the NOx emission limit of 0.2 g/bhphr set for the year 2010 is considered.

  3. Study on Reaction Products in Plasma-Assisted Selective Catalytic Reduction of NOx

    NASA Astrophysics Data System (ADS)

    Yoshizawa, Hayato; Tochikubo, Fumiyoshi; Uchida, Satoshi; Watanabe, Tsuneo

    Since the gas discharge plasma easily converts NO to NO2, which can be reduced more actively in selective catalytic reduction with hydrocarbons (HC-SCR), the plasma-assisted HC-SCR is an effective method for NOx reduction from diesel engine exhaust gases. In this work, the relation between NOx removal and reaction products is investigated in plasma-assisted HC-SCR in simulated flue gas as parameters of gas composition, plasma specific energy and catalyst temperature. C2H4 is used as a hydrocarbon and commercially available Al2O3 is used as a catalyst. After the plasma treatment of simulated flue gas, HCHO and HCOOH were generated as by-products, while NO was effectively converted to NO2. These by-products were confirmed to be reactive at lower catalyst temperature than C2H4 in HC-SCR. The relation between NOx removal and reaction products suggests that HCHO and HCOOH contribute the effective NOx reduction at low catalyst temperature in plasma-assisted HC-SCR.

  4. Impact of sulfation and desulfation on NOx reduction using Cu-chabazite SCR catalysts

    DOE PAGESBeta

    Brookshear, Daniel William; Nam, Jeong -Gil; Nguyen, Ke; Toops, Todd J.; Binder, Andrew J.

    2015-06-05

    This bench reactor study investigates the impact of gaseous sulfur on the NOx reduction activity of Cu-chabazite SCR (Cu-CHA) catalysts at SO2 concentrations representative of marine diesel engine exhaust. After two hours of 500 ppm SO2 exposure at 250 and 400 °C in the simulated diesel exhaust gases, the NOx reduction activity of the sulfated Cu-CHA SCR catalysts is severely degraded at evaluation temperatures below 250 °C; however, above 250 °C the impact of sulfur exposure is minimal. EPMA shows that sulfur is located throughout the washcoat and along the entire length of the sulfated samples. Interestingly, BET measurements revealmore » that the sulfated samples have a 20% decrease in surface area. Moreover, the sulfated samples show a decrease in NOx/nitrate absorption during NO exposure in a DRIFTS reactor which suggests that Cu sites in the catalyst are blocked by the presence of sulfur. SO2 exposure also results in an increase in NH3 storage capacity, possibly due to the formation of ammonium sulfate species in the sulfated samples. In all cases, lean thermal treatments as low as 500 °C reverse the effects of sulfur exposure and restore the NOx reduction activity of the Cu-CHA catalyst to that of the fresh condition.« less

  5. Investigating the impacts of aviation NOX, SO2 and black carbon emissions on ozone, aerosol and climate.

    NASA Astrophysics Data System (ADS)

    Kapadia, Zarashpe; Borman, Duncan; Spracklen, Dominick; Arnold, Stephen; Mann, Graham; Williams, Paul

    2013-04-01

    Aviation is currently responsible for 3% of global anthropogenic CO2 emissions, but 2-14% of anthropogenic induced warming due to the co-emission of NOX, SO2 and black carbon and formation of contrails. The impact of aviation emissions on ozone and aerosol is uncertain with recent research demonstrating the need to include atmospheric nitrate chemistry. The inclusion of nitrate chemistry may lead to a 20% reduction in aviation induced ozone forcing estimates due to the competition for atmospheric oxidants such as OH . Compounding this, uncertainties relating to the effects of NOx on ozone and methane illustrate the need for refining the understanding of aviation induced impacts. Furthermore the role of aerosol microphysics in controlling the climate impacts of aviation has not yet been explored. Here we use the TOMCAT 3-D chemical transport model coupled to the GLOMAP-mode aerosol microphysics model to quantify the impacts of aviation NOX, SO2 and BC emissions on ozone, aerosol and climate. GLOMAP-mode treats size resolved aerosol using a two-moment modal approach. We evaluate the effects of nitrate processing on the diagnosed impacts of aviation emissions on atmospheric composition including the first assessment of the impact on the global concentrations of cloud condensation nuclei. We investigate interactions between gas-phase oxidant photochemistry and aerosol microphysics in regions influenced by aircraft emissions, using fully-coupled tropospheric chemistry and multi-component aerosol treatment (BC, sulphate, nitrate). Finally, we use a 3-D radiative transfer model to quantify the ozone and aerosol direct and indirect radiative effects of aviation emissions. The work presented here is part of a wider research project which will be the first study to combine aviation NOX, SO2 and black carbon emission in a global size-resolved model which considers atmospheric nitrate chemistry, which will aim to add to the science surrounding present day aviation impacts by

  6. Characterization of NOx, SO2, ethene, and propene from industrial emission sources in Houston, Texas

    NASA Astrophysics Data System (ADS)

    Washenfelder, R. A.; Trainer, M.; Frost, G. J.; Ryerson, T. B.; Atlas, E. L.; de Gouw, J. A.; Flocke, F. M.; Fried, A.; Holloway, J. S.; Parrish, D. D.; Peischl, J.; Richter, D.; Schauffler, S. M.; Walega, J. G.; Warneke, C.; Weibring, P.; Zheng, W.

    2010-08-01

    The Houston-Galveston-Brazoria urban area contains industrial petrochemical sources that emit volatile organic compounds and nitrogen oxides, resulting in rapid and efficient ozone production downwind. During September to October 2006, the NOAA WP-3D aircraft conducted research flights as part of the second Texas Air Quality Study (TexAQS II). We use measurements of NOx, SO2, and speciated hydrocarbons from industrial sources in Houston to derive source emission ratios and compare these to emission inventories and the first Texas Air Quality Study (TexAQS) in 2000. Between 2000 and 2006, NOx/CO2 emission ratios changed by an average of -29% ± 20%, while a significant trend in SO2/CO2 emission ratios was not observed. We find that high hydrocarbon emissions are routine for the isolated petrochemical facilities. Ethene (C2H4) and propene (C3H6) are the major contributors to ozone formation based on calculations of OH reactivity for organic species including C2-C10 alkanes, C2-C5 alkenes, ethyne, and C2-C5 aldehydes and ketones. Measured ratios of C2H4/NOx and C3H6/NOx exceed emission inventory values by factors of 1.4-20 and 1-24, respectively. We examine trends in C2H4/NOx and C3H6/NOx ratios between 2000 and 2006 for the isolated petrochemical sources and estimate a change of -30% ± 30%, with significant day-to-day and within-plume variability. Median ambient mixing ratios of ethene and propene in Houston show decreases of -52% and -48%, respectively, between 2000 and 2006. The formaldehyde, acetaldehyde, and peroxyacetyl nitrate products produced by alkene oxidation are observed downwind, and their time evolution is consistent with the rapid photochemistry that also produces ozone.

  7. The Observed Response of Ozone Monitoring Instrument (OMI) NO2 Columns to NOx Emission Controls on Power Plants in the United States: 2005-2011

    NASA Technical Reports Server (NTRS)

    Duncan, Bryan N.; Yoshida, Yasuko; deFoy, Benjamin; Lamsal, Lok N.; Streets, David G.; Lu, Zifeng; Pickering, Kenneth E.; Krotkov, Nickolay A.

    2013-01-01

    We show that Aura Ozone Monitoring Instrument (OMI) nitrogen dioxide (NO2) tropospheric column data may be used to assess changes of the emissions of nitrogen oxides (NOx) from power plants in the United States, though careful interpretation of the data is necessary. There is a clear response for OMI NO2 data to NOx emission reductions from power plants associated with the implementation of mandated emission control devices (ECDs) over the OMI record (2005e2011). This response is scalar for all intents and purposes, whether the reduction is rapid or incremental over several years. However, it is variable among the power plants, even for those with the greatest absolute decrease in emissions. We document the primary causes of this variability, presenting case examples for specific power plants.

  8. Towards Ideal NOx and CO2 Emission Control Technology for Bio-Oils Combustion Energy System Using a Plasma-Chemical Hybrid Process

    NASA Astrophysics Data System (ADS)

    Okubo, M.; Fujishima, H.; Yamato, Y.; Kuroki, T.; Tanaka, A.; Otsuka, K.

    2013-03-01

    A pilot-scale low-emission boiler system consisting of a bio-fuel boiler and plasma-chemical hybrid NOx removal system is investigated. This system can achieve carbon neutrality because the bio-fuel boiler uses waste vegetable oil as one of the fuels. The plasma-chemical hybrid NOx removal system has two processes: NO oxidation by ozone produced from plasma ozonizers and NO2 removal using a Na2SO3 chemical scrubber. Test demonstrations of the system are carried out for mixed oils (mixture of A-heavy oil and waste vegetable oil). Stable combustion is achieved for the mixed oil (20 - 50% waste vegetable oil). Properties of flue gas—e.g., O2, CO2 and NOx—when firing mixed oils are nearly the same as those when firing heavy oil for an average flue gas flow rate of 1000 Nm3/h. NOx concentrations at the boiler outlet are 90 - 95 ppm. Furthermore, during a 300-min continuous operation when firing 20% mixed oil, NOx removal efficiency of more than 90% (less than 10 ppm NOx emission) is confirmed. In addition, the CO2 reduction when heavy oil is replaced with waste vegetable oil is estimated. The system comparison is described between the plasma-chemical hybrid NOx removal and the conventional technology.

  9. Recent advances in automotive catalysis for NOx emission control by small-pore microporous materials.

    PubMed

    Beale, A M; Gao, F; Lezcano-Gonzalez, I; Peden, C H F; Szanyi, J

    2015-10-21

    The ever increasing demand to develop highly fuel efficient engines coincides with the need to minimize air pollution originating from the exhaust gases of internal combustion engines. Dramatically improved fuel efficiency can be achieved at air-to-fuel ratios much higher than stoichiometric. In the presence of oxygen in large excess, however, traditional three-way catalysts are unable to reduce NOx. Among the number of lean-NOx reduction technologies, selective catalytic reduction (SCR) of NOx by NH3 over Cu- and Fe-ion exchanged zeolite catalysts has been extensively studied over the past 30+ years. Despite the significant advances in developing a viable practical zeolite-based catalyst for lean NOx reduction, the insufficient hydrothermal stabilities of the zeolite structures considered cast doubts about their real-world applicability. During the past decade renewed interest in zeolite-based lean NOx reduction was spurred by the discovery of the very high activity of Cu-SSZ-13 (and the isostructural Cu-SAPO-34) in the NH3-SCR of NOx. These new, small-pore zeolite-based catalysts not only exhibited very high NOx conversion and N2 selectivity, but also exhibited exceptionally high hydrothermal stability at high temperatures. In this review we summarize the key discoveries of the past ∼5 years that led to the introduction of these catalysts into practical applications. This review first briefly discusses the structure and preparation of the CHA structure-based zeolite catalysts, and then summarizes the key learnings of the rather extensive (but not complete) characterisation work. Then we summarize the key findings of reaction kinetic studies, and provide some mechanistic details emerging from these investigations. At the end of the review we highlight some of the issues that still need to be addressed in automotive exhaust control catalysis.

  10. Recent advances in automotive catalysis for NOx emission control by small-pore microporous materials.

    PubMed

    Beale, A M; Gao, F; Lezcano-Gonzalez, I; Peden, C H F; Szanyi, J

    2015-10-21

    The ever increasing demand to develop highly fuel efficient engines coincides with the need to minimize air pollution originating from the exhaust gases of internal combustion engines. Dramatically improved fuel efficiency can be achieved at air-to-fuel ratios much higher than stoichiometric. In the presence of oxygen in large excess, however, traditional three-way catalysts are unable to reduce NOx. Among the number of lean-NOx reduction technologies, selective catalytic reduction (SCR) of NOx by NH3 over Cu- and Fe-ion exchanged zeolite catalysts has been extensively studied over the past 30+ years. Despite the significant advances in developing a viable practical zeolite-based catalyst for lean NOx reduction, the insufficient hydrothermal stabilities of the zeolite structures considered cast doubts about their real-world applicability. During the past decade renewed interest in zeolite-based lean NOx reduction was spurred by the discovery of the very high activity of Cu-SSZ-13 (and the isostructural Cu-SAPO-34) in the NH3-SCR of NOx. These new, small-pore zeolite-based catalysts not only exhibited very high NOx conversion and N2 selectivity, but also exhibited exceptionally high hydrothermal stability at high temperatures. In this review we summarize the key discoveries of the past ∼5 years that led to the introduction of these catalysts into practical applications. This review first briefly discusses the structure and preparation of the CHA structure-based zeolite catalysts, and then summarizes the key learnings of the rather extensive (but not complete) characterisation work. Then we summarize the key findings of reaction kinetic studies, and provide some mechanistic details emerging from these investigations. At the end of the review we highlight some of the issues that still need to be addressed in automotive exhaust control catalysis. PMID:25913215

  11. Numerical analysis of NOx reduction for compact design in marine urea-SCR system

    NASA Astrophysics Data System (ADS)

    Choi, Cheolyong; Sung, Yonmo; Choi, Gyung Min; Kim, Duck Jool

    2015-11-01

    In order to design a compact urea selective catalytic reduction system, numerical simulation was conducted by computational fluid dynamics tool. A swirl type static mixer and a mixing chamber were considered as mixing units in the system. It had great influence on flow characteristics and urea decomposition into ammonia. The mixer caused flow recirculation and high level of turbulence intensity, and the chamber increased residence time of urea-water-solution injected. Because of those effects, reaction rates of urea decomposition were enhanced in the region. When those mixing units were combined, it showed the maximum because the recirculation zone was significantly developed. NH3 conversion was maximized in the zone due to widely distributed turbulence intensity and high value of uniformity index. It caused improvement of NOx reduction efficiency of the system. It was possible to reduce 55% length of the chamber and connecting pipe without decrease of NOx reduction efficiency.

  12. The selective catalytic reduction of NOx over Ag/Al2O3 with isobutanol as the reductant

    DOE PAGESBeta

    Brookshear, Daniel William; Pihl, Josh A.; Toops, Todd J.; West, Brian H.; Prikhodko, Vitaly Y.

    2016-02-13

    Here, this study investigates the potential of isobutanol (iBuOH) as a reductant for the selective catalytic reduction (SCR) of NOx over 2 wt% Ag/Al2O3 between 150 and 550 °C and gas hourly space velocities (GHSV) between 10,000 and 35,000 h-1. The feed gas consists of 500 ppm NO, 5% H2O, 10% O2, and 375-1500 ppm iBuOH (C1:N ratios of 3-12); additionally, blends of 24 and 48% iBuOH in gasoline are evaluated. Over 90% NOx conversion is achieved between 300 and 400 C using pure iBuOH, including a 40% peak selectivity towards NH3 that could be utilized in a dual HC/NH3more » SCR configuration. The iBuOH/gasoline blends are only able to achieve greater than 90% NOx conversion when operated at a GHSV of 10,000 h-1 and employing a C1:N ratio of 12. Iso-butyraldehyde and NO2 appear to function as intermediates in the iBuOH-SCR mechanism, which mirrors the mechanism observed for EtOH-SCR. In general, the performance of iBuOH in the SCR of NOx over a Ag/Al2O3 catalyst is comparable with that of EtOH, although EtOH/gasoline blends display higher NOx reduction than iBuOH/gasoline blends. The key parameter in employing alcohols in SCR appears to be the C-OH:N ratio rather than the C1:N ratio.« less

  13. Impact of the 2008 Global Recession on air quality over the United States: Implications for surface ozone levels from changes in NOx emissions

    NASA Astrophysics Data System (ADS)

    Tong, Daniel; Pan, Li; Chen, Weiwei; Lamsal, Lok; Lee, Pius; Tang, Youhua; Kim, Hyuncheol; Kondragunta, Shobha; Stajner, Ivanka

    2016-09-01

    Satellite and ground observations detected large variability in nitrogen oxides (NOx) during the 2008 economic recession, but the impact of the recession on air quality has not been quantified. This study combines observed NOx trends and a regional chemical transport model to quantify the impact of the recession on surface ozone (O3) levels over the continental United States. The impact is quantified by simulating O3 concentrations under two emission scenarios: business-as-usual (BAU) and recession. In the BAU case, the emission projection from the Cross-State Air Pollution Rule is used to estimate the "would-be" NOx emission level in 2011. In the recession case, the actual NO2 trends observed from Air Quality System ground monitors and the Ozone Monitoring Instrument on the Aura satellite are used to obtain "realistic" changes in NOx emissions. The model prediction with the recession effect agrees better with ground O3 observations over time and space than the prediction with the BAU emission. The results show that the recession caused a 1-2 ppbv decrease in surface O3 concentration over the eastern United States, a slight increase (0.5-1 ppbv) over the Rocky Mountain region, and mixed changes in the Pacific West. The gain in air quality benefits during the recession, however, could be quickly offset by the much slower emission reduction rate during the post-recession period.

  14. SELECTIVE REDUCTION OF NOX IN OXYGEN RICH ENVIRONMENTS WITH PLASMA-ASSISTED CATALYSIS: CATALYST DEVELOPMENT AND MECHANISTIC STUDIES

    SciTech Connect

    Peden, C; Barlow, S; Hoard, J; Kwak, J; *Balmer-Millar, M; *Panov, A; Schmieg, S; Szanyi, J; Tonkyn, R

    2003-08-24

    The control of NOx (NO and NO2) emissions from so-called ''lean-burn'' vehicle engines remains a challenge. In recent years, there have been a number of reports that show that a plasma device combined with a catalyst can reduce as high as 90% or more of NOx in simulated diesel and other ''lean-burn'' exhaust. In the case of propylene containing simulated diesel exhaust, the beneficial role of a plasma treatment is now thought to be due to oxidation of NO to NO2, and the formation of partially oxidized hydrocarbons that are more active for the catalytic reduction of NO2 than propylene. Thus, the overall system can be most usefully described as hydrocarbon selective catalytic reduction (SCR) enhanced by 'reforming' the exhaust with a non-thermal plasma (NTP) device. For plasma-enhanced catalysis, both zeolite- and alumina-based materials have shown high activity, albeit in somewhat different temperature ranges, when preceded by an NTP reactor. This paper will briefly describe our research efforts aimed at optimizing the catalyst materials for NTP-catalysis devices based, in part, on our continuing studies of the NTP- and catalytic-reaction mechanisms. Various alkali- and alkaline earth-cation-exchanged Y zeolites have been prepared, their material properties characterized, and they have been tested as catalytic materials for NOx reduction in laboratory NTP-catalysis reactors. Interestingly, NO2 formed in the plasma and not subsequently removed over these catalysts, will back-convert to NO, albeit to varying extents depending upon the nature of the cation. Besides this comparative reactivity, we will also discuss selected synthesis strategies for enhancing the performance of these zeolite-based catalyst materials. A particularly important result from our mechanistic studies is the observation that aldehydes, formed during the plasma treatment of simulated diesel exhaust, are the important species for the reduction of NOx to N2. Indeed, acetaldehyde has been found to

  15. NOx lifetimes and emissions of cities and power plants in polluted background estimated by satellite observations

    NASA Astrophysics Data System (ADS)

    Liu, Fei; Beirle, Steffen; Zhang, Qiang; Dörner, Steffen; He, Kebin; Wagner, Thomas

    2016-04-01

    We present a new method to quantify NOx emissions and corresponding atmospheric lifetimes from OMI NO2 observations together with ECMWF wind fields without further model input for sources located in a polluted background. NO2 patterns under calm wind conditions are used as proxy for the spatial patterns of NOx emissions, and the effective atmospheric NOx lifetime is determined from the change of spatial patterns measured at larger wind speeds. Emissions are subsequently derived from the NO2 mass above the background, integrated around the source of interest. Lifetimes and emissions are estimated for 17 power plants and 53 cities located in non-mountainous regions across China and the USA. The derived lifetimes for the ozone season (May-September) are 3.8 ± 1.0 h (mean ± standard deviation) with a range of 1.8 to 7.5 h. The derived NOx emissions show generally good agreement with bottom-up inventories for power plants and cities. Regional inventory shows better agreement with top-down estimates for Chinese cities compared to global inventory, most likely due to different downscaling approaches adopted in the two inventories.

  16. AISI/DOE Technology Roadmap Program: Development of an O2-Enriched Furnace System for Reduced CO2 and NOx Emissions For the Steel Industry

    SciTech Connect

    Edward W. Grandmaison; David J. Poirier; Eric Boyd

    2003-01-20

    An oxygen-enriched furnace system for reduced CO2 and NOx emission has been developed. The furnace geometry, with a sidewall-mounted burner, was similar to configurations commonly encountered in a steel reheat furnace. The effect of stack oxygen concentration, oxygen enrichment level and air infiltration on fuel savings/CO2 reduction, NOx emissions and scale formation were investigated. The firing rate required to maintain the furnace temperature at 1100 C decreased linearly with increasing oxygen enrichment. At full oxygen enrichment a reduction of 40-45% in the firing rate was required to maintain furnace temperature. NOx emissions were relatively constant at oxygen enrichment levels below 60% and decreased concentration at all oxygen enrichment levels. Air infiltration also had an effect on NOx levels leading to emissions similar to those observed with no air infiltration but with similar stack oxygen concentrations. At high oxygen enrichment levels, there was a larger variation in the refractory surface-temperature on the roof and blind sidewall of the furnace. Scale habit, intactness, adhesion and oxidation rates were examined for five grades of steel over a range of stack oxygen concentrations and oxygen enrichment levels at 1100 degree C. The steel grade had the largest effect on scaling properties examined in this work. The stack oxygen concentration and the oxygen enrichment level had much smaller effects on the scaling properties.

  17. Low emissions combustor technology for high-speed civil transport engines

    NASA Technical Reports Server (NTRS)

    Niedzwiecki, Richard W.

    1992-01-01

    The topics covered include the following: NASA High Speed Research (HSR) ozone research objectives; NO(x) formation; emission reduction; High Speed Civil Transport (HSCT) supersonic cruise combustion operating conditions; NO(x) correlations; typical NO(x) characteristics of a current technology and low NO(x) combustors; HSCT emission reduction strategies; variation of NO(x) with equivalence ratio; the Emission Reduction Program; and emission reduction milestones.

  18. Novel cerium-tungsten mixed oxide catalyst for the selective catalytic reduction of NO(x) with NH3.

    PubMed

    Shan, Wenpo; Liu, Fudong; He, Hong; Shi, Xiaoyan; Zhang, Changbin

    2011-07-28

    A novel Ce-W mixed oxide catalyst prepared by homogeneous precipitation method presented nearly 100% NO(x) conversion in a wide temperature range from 250 to 425 °C for the selective catalytic reduction of NO(x) with NH(3) under an extremely high GHSV of 500,000 h(-1).

  19. The climate impact of ship NOx emissions: an improved estimate accounting for plume chemistry

    NASA Astrophysics Data System (ADS)

    Holmes, C. D.; Prather, M. J.; Vinken, G. C. M.

    2014-07-01

    Nitrogen oxide (NOx) emissions from maritime shipping produce ozone (O3) and hydroxyl radicals (OH), which in turn destroy methane (CH4). The balance between this warming (due to O3) and cooling (due to CH4) determines the net effect of ship NOx on climate. Previous estimates of the chemical impact and radiative forcing (RF) of ship NOx have generally assumed that plumes of ship exhaust are instantly diluted into model grid cells spanning hundreds of kilometers, even though this is known to produce biased results. Here we improve the parametric representation of exhaust-gas chemistry developed in the GEOS-Chem chemical transport model (CTM) to provide the first estimate of RF from shipping that accounts for sub-grid-scale ship plume chemistry. The CTM now calculates O3 production and CH4 loss both within and outside the exhaust plumes and also accounts for the effect of wind speed. With the improved modeling of plumes, ship NOx perturbations are smaller than suggested by the ensemble of past global modeling studies, but if we assume instant dilution of ship NOx on the grid scale, the CTM reproduces previous model results. Our best estimates of the RF components from increasing ship NOx emissions by 1 Tg(N) yr-1 are smaller than that given in the past literature: + 3.4 ± 0.85 mW m-2 (1σ confidence interval) from the short-lived ozone increase, -5.7 ± 1.3 mW m-2 from the CH4 decrease, and -1.7 ± 0.7 mW m-2 from the long-lived O3 decrease that accompanies the CH4 change. The resulting net RF is -4.0 ± 2.0 mW m-2 for emissions of 1 Tg(N) yr-1. Due to non-linearity in O3 production as a function of background NOx, RF from large changes in ship NOx emissions, such as the increase since preindustrial times, is about 20% larger than this RF value for small marginal emission changes. Using sensitivity tests in one CTM, we quantify sources of uncertainty in the RF components and causes of the ±30% spread in past model results; the main source of uncertainty is the

  20. The use of rice hulls for sustainable control of NOx emissions in deep space missions

    SciTech Connect

    Xu, X.H.; Shi, Y.; Chang, S.G.; Fisher, J.W.; Pisharody, S.; Moran, M.J.; Wignarajah, K.

    2001-12-21

    The use of the activated carbon produced from rice hulls to control NOx emissions for the future deep space missions has been demonstrated. The optimal carbonization temperature range was found to be between 600 C and 750 C. The burnoff of 61.8% was found at 700 C in pyrolysis and 750 C in activation. The BET surface area of the activated carbon from rice hulls was determined to be 172 m{sup 2}/g when prepared at 700 C. The presence of oxygen in flue gas is essential for effective adsorption of NO by the activated carbon. On the contrary, water vapor inhibits the adsorption efficiency of NO. Consequently, water vapor in flue gas should be removed by drying agents before adsorption to ensure high NO adsorption efficiency. All of NO in the flue gas was removed for more than one and a half hours when 10% oxygen was present and using a ratio of the carbon weight to the flue gas flow rate (W/F) of 15.4 g-min/L. The reduction of the adsorbed NO to form N{sub 2} can be effectively accomplished under anaerobic conditions at 550 C. For NO saturated activated carbon, the loss of carbon mass was determined to be about 0.16% of the activated carbon per cycle of regeneration. The reduction of the adsorbed NO also regenerates the activated carbon. The regenerated activated carbon exhibits improved NO adsorption efficiency.

  1. DEVELOPMENT OF HIGH ACTIVITY, CATALYTIC SYSTEMS FOR NOx REDUCTION

    SciTech Connect

    Unknown

    2001-12-01

    This project was directed at an investigation of catalytic NO{sub x} reduction on carbonaceous supports at low temperatures. The experimental work was conducted primarily in a packed bed reactor/gas flow system that was constructed for this work. The analytical techniques employed were mass spectrometry, NO{sub x} chemiluminescence, and gas chromatography. The experimental plan was focused on steady-state reactivity experiments, followed by temperature programmed desorption (TPD) of surface intermediates, and also selected temperature-programmed reaction (TPR) experiments. Both uncatalyzed and catalyzed (potassium-promoted) phenolic resin char, were investigated as well as the catalytic effect of additional CO in the gas phase.

  2. Evaluation of Reformer Produced Synthesis Gas for Emissions Reductions in Natural Gas Reciprocating Engines

    SciTech Connect

    Mark V. Scotto; Mark A. Perna

    2010-05-30

    Rolls-Royce Fuel Cell Systems (US) Inc. (RRFCS) has developed a system that produces synthesis gas from air and natural gas. A near-term application being considered for this technology is synthesis gas injection into reciprocating engines for reducing NOx emissions. A proof of concept study using bottled synthesis gas and a two-stroke reciprocating engine showed that injecting small amounts of highflammables content synthesis gas significantly improved combustion stability and enabled leaner engine operation resulting in over 44% reduction in NOx emissions. The actual NOx reduction that could be achieved in the field is expected to be engine specific, and in many cases may be even greater. RRFCS demonstrated that its synthesis gas generator could produce synthesis gas with the flammables content that was successfully used in the engine testing. An economic analysis of the synthesis gas approach estimates that its initial capital cost and yearly operating cost are less than half that of a competing NOx reduction technology, Selective Catalytic Reduction. The next step in developing the technology is an integrated test of the synthesis gas generator with an engine to obtain reliability data for system components and to confirm operating cost. RRFCS is actively pursuing opportunities to perform the integrated test. A successful integrated test would demonstrate the technology as a low-cost option to reduce NOx emissions from approximately 6,000 existing two-stroke, natural gas-fired reciprocating engines used on natural gas pipelines in North America. NOx emissions reduction made possible at a reasonable price by this synthesis gas technology, if implemented on 25% of these engines, would be on the order of 25,000 tons/year.

  3. CO2, NOx, and particle emissions from aircraft and support activities at a regional airport.

    PubMed

    Klapmeyer, Michael E; Marr, Linsey C

    2012-10-16

    The goal of this research was to quantify emissions of carbon dioxide (CO(2)), nitrogen oxides (NO(x)), particle number, and black carbon (BC) from in-use aircraft and related activity at a regional airport. Pollutant concentrations were measured adjacent to the airfield and passenger terminal at the Roanoke Regional Airport in Virginia. Observed NO(x) emission indices (EIs) for jet-powered, commuter aircraft were generally lower than those contained in the International Civil Aviation Organization databank for both taxi (same as idle) and takeoff engine settings. NO(x) EIs ranged from 1.9 to 3.7 g (kg fuel)(-1) across five types of aircraft during taxiing, whereas EIs were consistently higher, 8.8-20.6 g (kg fuel)(-1), during takeoff. Particle number EIs ranged from 1.4 × 10(16) to 7.1 × 10(16) (kg fuel)(-1) and were slightly higher in taxi mode than in takeoff mode for four of the five types of aircraft. Diurnal patterns in CO(2) and NO(x) concentrations were influenced mainly by atmospheric conditions, while patterns in particle number concentrations were attributable mainly to patterns in aircraft activity. CO(2) and NO(x) fluxes measured by eddy covariance were higher at the terminal than at the airfield and were lower than found in urban areas.

  4. Fuel-Air Mixing Effect on Nox Emissions for a Lean Premixed-Prevaporized Combustion System

    NASA Technical Reports Server (NTRS)

    Lee, Chi-Ming; Chun, Kue S.; Locke, Randy J.

    1995-01-01

    The lean premixed-prevaporized (LPP) concept effectively meets low nitrogen oxides (NOx) emission requirements for combustors with the high inlet temperature and pressure typical of the High-Speed Civil Transport (HSCT). For the LPP system fuel-air mixture uniformity is probably the most important factor for low NOx emissions. Previous studies have suggested that the fuel-air mixture uniformity can be severely affected by changing the number and configuration of fuel injection points. Therefore, an experimental study was performed to determine how the number of fuel injection points and their arrangement affect NOx emissions from an LPP system. The NOx emissions were measured by a gas-sampling probe in a flame-tube rig at the following conditions: inlet temperature of 810 K (1000 F), rig pressure of 10 atm, reference velocity of 150 ft/s, and residence time near 0.005 s. Additionally, a focused Schlieren diagnostic technique coupled with a high speed camera was used to provide a qualitative description of the spatial flow field.

  5. Ozone Trends Across the United States over a Period of Decreasing NOx and VOC Emissions

    EPA Science Inventory

    In this work, we evaluate ambient ozone trends at urban, suburban, and rural monitoring sites across the United States over a period of decreasing NOx and VOC emissions (1998–2013). We find that decreasing ozone trends generally occur in the summer, in less urbanized areas,...

  6. PHOTOCHEMICAL EFFECTS ON NOX AND CO EMISSIONS IN A BRAZILIAN SAVANNA

    EPA Science Inventory

    Land clearing and burning in the tropics often results in increased solar irradiation of soil and surface organic matter. This increased light exposure may impact the emissions of nitrogen oxides (NOx) and carbon monoxide (CO), trace gases that play an important role in troposph...

  7. NOX AND CO EMISSIONS FROM SOIL AND SURFACE LITTER IN A BRAZILIAN SAVANNA

    EPA Science Inventory

    Land clearing and burning in the tropics often results in increased solar irradiation of soil and surface organic matter. This increased light exposure and surface heating may impact the emissions of nitrogen oxides (NOx) and carbon monoxide (CO), trace gases that play an importa...

  8. 40 CFR 96.154 - Compliance with CAIR NOX emissions limitation.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 21 2014-07-01 2014-07-01 false Compliance with CAIR NOX emissions limitation. 96.154 Section 96.154 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... section, on a first-in, first-out (FIFO) accounting basis in the following order: (i) Any CAIR...

  9. Worldwide biogenic soil NOx emission estimates from OMI NO2 observations and the GEOS-Chem model

    NASA Astrophysics Data System (ADS)

    Vinken, Geert; Boersma, Folkert; Maasakkers, Bram; Martin, Randall

    2014-05-01

    Bacteria in soils are an important source of biogenic nitrogen oxides (NOx = NO + NO2), which are important precursors for ozone (O3) formation. Furthermore NOx emissions contribute to increased nitrogen deposition and particulate matter formation. Bottom-up estimates of global soil NOx emissions range from 4 to 27 Tg N / yr, reflecting our incomplete knowledge of emission factors and processes driving these emissions. In this study we used, for the first time, OMI NO2 columns on all continents to reduce the uncertainty in soil NOx emissions. Regions and months dominated by soil NOx emissions were identified using a filtering scheme in the GEOS-Chem chemistry transport model. Consequently, we compared OMI observed NO2 observed columns to GEOS-Chem simulated columns and provide constraints for these months in 11 regions. This allows us to provide a top-down emission inventory for 2005 for soil NOx emissions from all continents. Our total global soil NOx emission inventory amounts to 10 Tg N / yr. Our estimate is 4% higher than the GEOS-Chem a priori (Hudman et al., 2012), but substantial regional differences exist (e.g. +20% for Sahel and India; and -40% for mid-USA). We furthermore observed a stronger seasonal cycle in the Sahel region, indicating directions for possible future improvements to the parameterization currently used in GEOS-Chem. We validated NO2 concentrations simulated with this new top-down inventory against surface NO2 measurements from monitoring stations in Africa, the USA and Europe. On the whole, we conclude that simulations with our new top-down inventory better agree with measurements. Our work shows that satellite retrieved NO2 columns can improve estimates of soil NOx emissions over sparsely monitored remote rural areas. We show that the range in previous estimates of soil NOx emissions is too large, and global emissions are most likely around 10 Tg N/yr, in agreement with the most recent parameterizations.

  10. Commercial introduction of the Advanced NOxTECH system

    SciTech Connect

    Sudduth, B.C.

    1997-12-31

    NOxTECH is BACT for diesel electric generators. Emissions of NO{sub x} are reduced 95% or more with substantial concurrent reductions in CO, particulates, and ROG`s. No engine modifications or other exhaust aftertreatments can remove all criteria pollutants as effectively as NOxTECH. The NOxTECH system reliably maintains NH{sub 3} slip below 2 ppm. Unlike other emissions controls, NOxTECH does not generate hazardous by-products. The Advanced NOxTECH system reduces the size, weight, and cost for BACT emissions reductions. Based on the operation of a 150 kW prototype, NOxTECH, Inc. is quoting commercial units for diesel electric generators. Advanced NOxTECH equipment costs about half as much as SCR systems, and NO{sub x} reduction can exceed 95% with guarantees for emissions compliance.

  11. A Synthetic Pseudo-Rh: NOx Reduction Activity and Electronic Structure of Pd-Ru Solid-solution Alloy Nanoparticles.

    PubMed

    Sato, Katsutoshi; Tomonaga, Hiroyuki; Yamamoto, Tomokazu; Matsumura, Syo; Zulkifli, Nor Diana Binti; Ishimoto, Takayoshi; Koyama, Michihisa; Kusada, Kohei; Kobayashi, Hirokazu; Kitagawa, Hiroshi; Nagaoka, Katsutoshi

    2016-06-24

    Rh is one of the most important noble metals for industrial applications. A major fraction of Rh is used as a catalyst for emission control in automotive catalytic converters because of its unparalleled activity toward NOx reduction. However, Rh is a rare and extremely expensive element; thus, the development of Rh alternative composed of abundant elements is desirable. Pd and Ru are located at the right and left of Rh in the periodic table, respectively, nevertheless this combination of elements is immiscible in the bulk state. Here, we report a Pd-Ru solid-solution-alloy nanoparticle (PdxRu1-x NP) catalyst exhibiting better NOx reduction activity than Rh. Theoretical calculations show that the electronic structure of Pd0.5Ru0.5 is similar to that of Rh, indicating that Pd0.5Ru0.5 can be regarded as a pseudo-Rh. Pd0.5Ru0.5 exhibits better activity than natural Rh, which implies promising applications not only for exhaust-gas cleaning but also for various chemical reactions.

  12. A Synthetic Pseudo-Rh: NOx Reduction Activity and Electronic Structure of Pd–Ru Solid-solution Alloy Nanoparticles

    PubMed Central

    Sato, Katsutoshi; Tomonaga, Hiroyuki; Yamamoto, Tomokazu; Matsumura, Syo; Zulkifli, Nor Diana Binti; Ishimoto, Takayoshi; Koyama, Michihisa; Kusada, Kohei; Kobayashi, Hirokazu; Kitagawa, Hiroshi; Nagaoka, Katsutoshi

    2016-01-01

    Rh is one of the most important noble metals for industrial applications. A major fraction of Rh is used as a catalyst for emission control in automotive catalytic converters because of its unparalleled activity toward NOx reduction. However, Rh is a rare and extremely expensive element; thus, the development of Rh alternative composed of abundant elements is desirable. Pd and Ru are located at the right and left of Rh in the periodic table, respectively, nevertheless this combination of elements is immiscible in the bulk state. Here, we report a Pd–Ru solid-solution-alloy nanoparticle (PdxRu1-x NP) catalyst exhibiting better NOx reduction activity than Rh. Theoretical calculations show that the electronic structure of Pd0.5Ru0.5 is similar to that of Rh, indicating that Pd0.5Ru0.5 can be regarded as a pseudo-Rh. Pd0.5Ru0.5 exhibits better activity than natural Rh, which implies promising applications not only for exhaust-gas cleaning but also for various chemical reactions. PMID:27340099

  13. A Synthetic Pseudo-Rh: NOx Reduction Activity and Electronic Structure of Pd–Ru Solid-solution Alloy Nanoparticles

    NASA Astrophysics Data System (ADS)

    Sato, Katsutoshi; Tomonaga, Hiroyuki; Yamamoto, Tomokazu; Matsumura, Syo; Zulkifli, Nor Diana Binti; Ishimoto, Takayoshi; Koyama, Michihisa; Kusada, Kohei; Kobayashi, Hirokazu; Kitagawa, Hiroshi; Nagaoka, Katsutoshi

    2016-06-01

    Rh is one of the most important noble metals for industrial applications. A major fraction of Rh is used as a catalyst for emission control in automotive catalytic converters because of its unparalleled activity toward NOx reduction. However, Rh is a rare and extremely expensive element; thus, the development of Rh alternative composed of abundant elements is desirable. Pd and Ru are located at the right and left of Rh in the periodic table, respectively, nevertheless this combination of elements is immiscible in the bulk state. Here, we report a Pd–Ru solid-solution-alloy nanoparticle (PdxRu1-x NP) catalyst exhibiting better NOx reduction activity than Rh. Theoretical calculations show that the electronic structure of Pd0.5Ru0.5 is similar to that of Rh, indicating that Pd0.5Ru0.5 can be regarded as a pseudo-Rh. Pd0.5Ru0.5 exhibits better activity than natural Rh, which implies promising applications not only for exhaust-gas cleaning but also for various chemical reactions.

  14. A Synthetic Pseudo-Rh: NOx Reduction Activity and Electronic Structure of Pd-Ru Solid-solution Alloy Nanoparticles.

    PubMed

    Sato, Katsutoshi; Tomonaga, Hiroyuki; Yamamoto, Tomokazu; Matsumura, Syo; Zulkifli, Nor Diana Binti; Ishimoto, Takayoshi; Koyama, Michihisa; Kusada, Kohei; Kobayashi, Hirokazu; Kitagawa, Hiroshi; Nagaoka, Katsutoshi

    2016-01-01

    Rh is one of the most important noble metals for industrial applications. A major fraction of Rh is used as a catalyst for emission control in automotive catalytic converters because of its unparalleled activity toward NOx reduction. However, Rh is a rare and extremely expensive element; thus, the development of Rh alternative composed of abundant elements is desirable. Pd and Ru are located at the right and left of Rh in the periodic table, respectively, nevertheless this combination of elements is immiscible in the bulk state. Here, we report a Pd-Ru solid-solution-alloy nanoparticle (PdxRu1-x NP) catalyst exhibiting better NOx reduction activity than Rh. Theoretical calculations show that the electronic structure of Pd0.5Ru0.5 is similar to that of Rh, indicating that Pd0.5Ru0.5 can be regarded as a pseudo-Rh. Pd0.5Ru0.5 exhibits better activity than natural Rh, which implies promising applications not only for exhaust-gas cleaning but also for various chemical reactions. PMID:27340099

  15. Effects of gas compositions on NOx reduction by selective non-catalytic reduction with ammonia in a simulated cement precalciner atmosphere.

    PubMed

    Fan, Weiyi; Zhu, Tianle; Sun, Yifei; Lv, Dong

    2014-10-01

    The effects of gas compositions on NOx reduction and NH3 slip by selective non-catalytic reduction (SNCR) with NH3 were investigated in a simulated cement precalciner atmosphere. The results show that the presence of H2O improves NOx reduction and widens the reduction temperature window significantly. O2 is indispensable for reducing NOx. The optimum reduction temperature decreases and the temperature window widens to a lower temperature with the increase of O2 content. In addition, the increase of O2 content also results in a decrease of the maximum NOx reduction efficiency. The effect of SO2 on NOx reduction is negligible in the simulated precalciner atmosphere. To increase CO concentration makes NO reduction take place at relatively low temperatures. However, NH3 will tend to be oxidized into NO instead of reducing NO after entering the stream containing O2 at high temperatures if it is initially blended with a high concentration of CO in an oxygen-free environment. The increase of H2O, O2, SO2 or CO concentration is helpful to reduce NH3 slip in the temperature region below 900°C. These effects are resulted from the fact that the generation and consumption of O and OH radicals which are crucial to NO reduction and formation can be influenced by the four gas compositions. In industrial operation of SNCR for cement precalciner, these effects should be taken into account to increase NOx reduction efficiency and avoid NH3 slip.

  16. Effects of gas compositions on NOx reduction by selective non-catalytic reduction with ammonia in a simulated cement precalciner atmosphere.

    PubMed

    Fan, Weiyi; Zhu, Tianle; Sun, Yifei; Lv, Dong

    2014-10-01

    The effects of gas compositions on NOx reduction and NH3 slip by selective non-catalytic reduction (SNCR) with NH3 were investigated in a simulated cement precalciner atmosphere. The results show that the presence of H2O improves NOx reduction and widens the reduction temperature window significantly. O2 is indispensable for reducing NOx. The optimum reduction temperature decreases and the temperature window widens to a lower temperature with the increase of O2 content. In addition, the increase of O2 content also results in a decrease of the maximum NOx reduction efficiency. The effect of SO2 on NOx reduction is negligible in the simulated precalciner atmosphere. To increase CO concentration makes NO reduction take place at relatively low temperatures. However, NH3 will tend to be oxidized into NO instead of reducing NO after entering the stream containing O2 at high temperatures if it is initially blended with a high concentration of CO in an oxygen-free environment. The increase of H2O, O2, SO2 or CO concentration is helpful to reduce NH3 slip in the temperature region below 900°C. These effects are resulted from the fact that the generation and consumption of O and OH radicals which are crucial to NO reduction and formation can be influenced by the four gas compositions. In industrial operation of SNCR for cement precalciner, these effects should be taken into account to increase NOx reduction efficiency and avoid NH3 slip. PMID:25065808

  17. 40 CFR 75.70 - NOX mass emissions provisions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... affected unit that is subject to an Acid Rain emissions limitation shall comply with the initial... unit that is not subject to an Acid Rain emissions limitation shall comply with the initial... that is subject to an Acid Rain emissions limitation shall comply with the initial certification...

  18. 40 CFR 75.70 - NOX mass emissions provisions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... affected unit that is subject to an Acid Rain emissions limitation shall comply with the initial... unit that is not subject to an Acid Rain emissions limitation shall comply with the initial... that is subject to an Acid Rain emissions limitation shall comply with the initial certification...

  19. 40 CFR 75.70 - NOX mass emissions provisions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... affected unit that is subject to an Acid Rain emissions limitation shall comply with the initial... unit that is not subject to an Acid Rain emissions limitation shall comply with the initial... that is subject to an Acid Rain emissions limitation shall comply with the initial certification...

  20. 40 CFR 75.70 - NOX mass emissions provisions.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... affected unit that is subject to an Acid Rain emissions limitation shall comply with the initial... unit that is not subject to an Acid Rain emissions limitation shall comply with the initial... that is subject to an Acid Rain emissions limitation shall comply with the initial certification...

  1. 40 CFR 75.70 - NOX mass emissions provisions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... affected unit that is subject to an Acid Rain emissions limitation shall comply with the initial... unit that is not subject to an Acid Rain emissions limitation shall comply with the initial... that is subject to an Acid Rain emissions limitation shall comply with the initial certification...

  2. Chemiluminescence analyzer of NOx as a high-throughput screening tool in selective catalytic reduction of NO

    NASA Astrophysics Data System (ADS)

    Oh, Kwang Seok; Woo, Seong Ihl

    2011-10-01

    A chemiluminescence-based analyzer of NOx gas species has been applied for high-throughput screening of a library of catalytic materials. The applicability of the commercial NOx analyzer as a rapid screening tool was evaluated using selective catalytic reduction of NO gas. A library of 60 binary alloys composed of Pt and Co, Zr, La, Ce, Fe or W on Al2O3 substrate was tested for the efficiency of NOx removal using a home-built 64-channel parallel and sequential tubular reactor. The NOx concentrations measured by the NOx analyzer agreed well with the results obtained using micro gas chromatography for a reference catalyst consisting of 1 wt% Pt on γ-Al2O3. Most alloys showed high efficiency at 275 °C, which is typical of Pt-based catalysts for selective catalytic reduction of NO. The screening with NOx analyzer allowed to select Pt-Ce(X) (X=1-3) and Pt-Fe(2) as the optimal catalysts for NOx removal: 73% NOx conversion was achieved with the Pt-Fe(2) alloy, which was much better than the results for the reference catalyst and the other library alloys. This study demonstrates a sequential high-throughput method of practical evaluation of catalysts for the selective reduction of NO.

  3. Mixing and NO(x) Emission Calculations of Confined Reacting Jet Flows in a Cylindrical Duct

    NASA Technical Reports Server (NTRS)

    Holdeman, James D. (Technical Monitor); Oechsle, Victor L.

    2003-01-01

    Rapid mixing of cold lateral jets with hot cross-stream flows in confined configurations is of practical interest in gas turbine combustors as it strongly affects combustor exit temperature quality, and gaseous emissions in for example rich-lean combustion. It is therefore important to further improve our fundamental understanding of the important processes of dilution jet mixing especially when the injected jet mass flow rate exceeds that of the cross-stream. The results reported in this report describe some of the main flow characteristics which develop in the mixing process in a cylindrical duct. A 3-dimensional tool has been used to predict the mixing flow field characteristics and NOx emission in a quench section of an RQL combustor, Eighteen configurations have been analyzed in a circular geometry in a fully reacting environment simulating the operating condition of an actual RQL gas turbine combustion liner. The evaluation matrix was constructed by varying three parameters: 1) jet-to-mainstream momentum-flux ratio (J), 2) orifice shape or orifice aspect ratio, and 3) slot slant angle. The results indicate that the mixing flow field significantly varies with the value of the jet penetration and subsequently, slanting elongated slots generally improve the mixing uniformity at high J conditions. Round orifices produce more uniform mixing and low NO(x) emissions at low J due to the strong and adequate jet penetration. No significant correlation was found between the NO(x) production rates and the mixing deviation parameters, however, strong correlation was found between NO(x) formation and jet penetration. In the computational results, most of the NO(x) formation occurred behind the orifice starting at the orifice wake region. Additional NO(x) is formed upstream of the orifice in certain configurations with high J conditions due to the upstream recirculation.

  4. 40 CFR 51.122 - Emissions reporting requirements for SIP revisions relating to budgets for NOX emissions.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... NOX emissions data as described in this section. (c) Each revision must provide for periodic reporting... reporting requirements of 40 CFR part 75, then the state need not provide an every-year cycle report to EPA...) of this section. (3) Through 2011, reports are to be submitted according to the schedule in Table...

  5. 40 CFR 51.122 - Emissions reporting requirements for SIP revisions relating to budgets for NOX emissions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... NOX emissions data as described in this section. (c) Each revision must provide for periodic reporting... reporting requirements of 40 CFR part 75, then the state need not provide an every-year cycle report to EPA...) of this section. (3) Through 2011, reports are to be submitted according to the schedule in Table...

  6. Impacts of biogenic emissions of VOC and NOx on tropospheric ozone during summertime in eastern China.

    PubMed

    Wang, Qin'geng; Han, Zhiwei; Wang, Tijian; Zhang, Renjian

    2008-05-20

    This study is intended to understand and quantify the impacts of biogenic emissions of volatile organic compounds (VOC) and nitrogen oxides (NO(x)) on the formation of tropospheric ozone during summertime in eastern China. The model system consists of the non-hydrostatic mesoscale meteorological model (MM5) and a tropospheric chemical and transport model (TCTM) with the updated carbon-bond chemical reaction mechanism (CBM-IV). The spatial resolution of the system domain is 30 km x 30 km. The impacts of biogenic emissions are investigated by performing simulations (36 h) with and without biogenic emissions, while anthropogenic emissions are constant. The results indicate that biogenic emissions have remarkable impacts on surface ozone in eastern China. In big cities and their surrounding areas, surface ozone formation tends to be VOC-limited. The increase in ozone concentration by biogenic VOC is generally 5 ppbv or less, but could be more than 10 ppbv or even 30 ppbv in some local places. The impacts of biogenic NO(x) are different or even contrary in different regions, depending on the relative availability of NO(x) and VOC. The surface ozone concentrations reduced or increased by the biogenic NO(x) could be as much as 10 ppbv or 20 ppbv, respectively. The impacts of biogenic emissions on ozone aloft are generally restricted to the boundary layer and generally more obvious during the daytime than during the nighttime. This study is useful for understanding the role of biogenic emissions and for planning strategies for surface ozone abatement in eastern China. Due to limitations of the emission inventories used and the highly non-linear nature of zone formation, however, some uncertainties remain in the results.

  7. Cu-SSZ-39, an active and hydrothermally stable catalyst for the selective catalytic reduction of NOx.

    PubMed

    Moliner, Manuel; Franch, Cristina; Palomares, Eduardo; Grill, Marie; Corma, Avelino

    2012-08-25

    A Cu-exchanged SSZ-39 zeolite has been synthesized and tested for the selective catalytic reduction (SCR) of NOx. This material shows an excellent catalytic activity, and most importantly, an extraordinary hydrothermal stability.

  8. Flame Tube NOx Emissions Using a Lean-Direct-Wall-Injection Combustor Concept

    NASA Technical Reports Server (NTRS)

    Tacina, Robert R.; Wey, Changlie; Choi, Kyung J.

    2001-01-01

    A low-NOx emissions combustor concept has been demonstrated in flame tube tests. A lean-direct injection concept was used where the fuel is injected directly into the flame zone and the overall fuel-air mixture is lean. In this concept the air is swirled upstream of a venturi section and the fuel is injected radially inward into the air stream from the throat section using a plain-orifice injector. Configurations have two-, four-, or six-wall fuel injectors and in some cases fuel is also injected from an axially located simplex pressure atomizer. Various orifice sizes of the plain-orifice injector were evaluated for the effect on NOx. Test conditions were inlet temperatures up to 8 1 OK, inlet pressures up to 2760 kPa, and flame temperatures up to 2100 K. A correlation is developed relating the NOx emissions to inlet temperature, inlet pressure, fuel-air ratio and pressure drop. Assuming that 15 percent of the combustion air would be used for liner cooling and using an advanced engine cycle, for the best configuration, the NOx emissions using the correlation is estimated to be <75 percent of the 1996 ICAO standard.

  9. Constraints on ship NOx emissions in Europe using OMI NO2 observations

    NASA Astrophysics Data System (ADS)

    Vinken, G. C. M.; Boersma, K. F.

    2012-04-01

    About 90% of world trade is transported by oceangoing ships, and seaborne trade has been shown to have increased by about 5% per year in the past decade. Global ship traffic is currently not regulated under international treaties (e.g. Kyoto protocol) and ships are still allowed to burn low-grade bunker fuel. As a result, ships emit large quantities of nitrogen oxides (NOx = NO + NO2), important precursors for ozone (O3) and particulate matter formation. Previous studies indicated that the global NOx emissions from shipping are in the range 3.0-10.4 Tg N per year (15-30% of total global NOx emissions). Because most ships sail within 400 km of the coast, it is important to understand the contribution of ship emissions to atmospheric composition in the densely populated coastal regions. Chemistry Transport Models (CTMs), in combination with emission inventories, are used to simulate atmospheric concentrations of air pollutants to assess the impact of ship emissions. However, these bottom-up inventories, based on extrapolation of a few engine measurements and strong assumptions, suffer from large uncertainties. In this study we provide top-down constraints on ship NOx emissions in Europe using satellite observations of NO2 columns. We use the nested version of the GEOS-Chem model (0.5°-0.667°) to simulate tropospheric NO2 columns over Europe for the years 2005-2006, using our plume-in-grid treatment of ship NOx emissions. We improve the NO2 retrievals from the Ozone Monitoring Instrument (OMI v2.0) by replacing the coarse a priori (TM4) vertical NO2 profiles (2°-3°) with the high-resolution GEOS-Chem profiles. This ensures consistency between the retrievals and model simulations. GEOS-Chem simulations of tropospheric NO2 columns show remarkable quantitative agreement with the observed OMI columns over Europe (R2=0.89, RMS difference < 0.2-1015 molec. cm-2), providing confidence in the ability of the model to simulate NO2 pollution over the European mainland. We

  10. A model investigation of the impact of increases in anthropogenic NOx emissions between 1967 and 1980 on tropospheric ozone

    NASA Technical Reports Server (NTRS)

    Dignon, J.; Hameed, S.

    1985-01-01

    The impact of anthropogenic NOx emission on tropospheric ozone has been investigated. Two statistical models were used for estimating annual global emissions of NOx and for driving the trend in the emission for the years 1966-1980. Both models show a steady increase in the NOx emission, except for two brief periods of leveling off: after 1973 and after 1978. The impact was estimated by calculating the rates of emissions as functions of latitude, longitude, and year, with a one-dimensional (latitudinal) model, which included coupled tropospheric photochemistry and diffusive meridional transport. Steady-state photochemical calculations with prescribed NOx emissions appropriate for 1966 and 1980 indicate an ozone increase of 8-11 percent in the Northern Hemisphere, a result compatible with the rise in ozone suggested by the observations.

  11. Changes in inorganic fine particulate matter sensitivities to precursors due to large-scale US emissions reductions.

    PubMed

    Holt, Jareth; Selin, Noelle E; Solomon, Susan

    2015-04-21

    We examined the impact of large US emissions changes, similar to those estimated to have occurred between 2005 and 2012 (high and low emissions cases, respectively), on inorganic PM2.5 sensitivities to further NOx, SO2, and NH3 emissions reductions using the chemical transport model GEOS-Chem. Sensitivities to SO2 emissions are larger year-round and across the US in the low emissions case than the high emissions case due to more aqueous-phase SO2 oxidation. Sensitivities to winter NOx emissions are larger in the low emissions case, more than 2× those of the high emissions case in parts of the northern Midwest. Sensitivities to NH3 emissions are smaller (∼40%) in the low emissions case, year-round, and across the US. Differences in NOx and NH3 sensitivities indicate an altered atmospheric acidity. Larger sensitivities to SO2 and NOx in the low emissions case imply that reducing these emissions may improve air quality more now than they would have in 2005; conversely, NH3 reductions may not improve air quality as much as previously assumed.

  12. Field test of available methods to measure remotely SOx and NOx emissions from ships

    NASA Astrophysics Data System (ADS)

    Balzani Lööv, J. M.; Alfoldy, B.; Gast, L. F. L.; Hjorth, J.; Lagler, F.; Mellqvist, J.; Beecken, J.; Berg, N.; Duyzer, J.; Westrate, H.; Swart, D. P. J.; Berkhout, A. J. C.; Jalkanen, J.-P.; Prata, A. J.; van der Hoff, G. R.; Borowiak, A.

    2014-08-01

    Methods for the determination of ship fuel sulphur content and NOx emission factors based on remote measurements have been compared in the harbour of Rotterdam and compared to direct stack emission measurements on the ferry Stena Hollandica. The methods were selected based on a review of the available literature on ship emission measurements. They were either optical (LIDAR, Differential Optical Absorption Spectroscopy (DOAS), UV camera), combined with model-based estimates of fuel consumption, or based on the so called "sniffer" principle, where SO2 or NOx emission factors are determined from simultaneous measurement of the increase of CO2 and SO2 or NOx concentrations in the plume of the ship compared to the background. The measurements were performed from stations at land, from a boat and from a helicopter. Mobile measurement platforms were found to have important advantages compared to the land-based ones because they allow optimizing the sampling conditions and sampling from ships on the open sea. Although optical methods can provide reliable results it was found that at the state of the art level, the "sniffer" approach is the most convenient technique for determining both SO2 and NOx emission factors remotely. The average random error on the determination of SO2 emission factors comparing two identical instrumental set-ups was 6%. However, it was found that apparently minor differences in the instrumental characteristics, such as response time, could cause significant differences between the emission factors determined. Direct stack measurements showed that about 14% of the fuel sulphur content was not emitted as SO2. This was supported by the remote measurements and is in agreement with the results of other field studies.

  13. Field test of available methods to measure remotely SO2 and NOx emissions from ships

    NASA Astrophysics Data System (ADS)

    Balzani Lööv, J. M.; Alfoldy, B.; Beecken, J.; Berg, N.; Berkhout, A. J. C.; Duyzer, J.; Gast, L. F. L.; Hjorth, J.; Jalkanen, J.-P.; Lagler, F.; Mellqvist, J.; Prata, F.; van der Hoff, G. R.; Westrate, H.; Swart, D. P. J.; Borowiak, A.

    2013-11-01

    Methods for the determination of ship fuel sulphur content and NOx emission factors from remote measurements have been compared in the harbour of Rotterdam and compared to direct stack emission measurements on the ferry Stena Hollandica. The methods were selected based on a review of the available literature on ship emission measurements. They were either optical (LIDAR, DOAS, UV camera), combined with model based estimates of fuel consumption, or based on the so called "sniffer" principle, where SO2 or NOx emission factors are determined from simultaneous measurement of the increase of CO2 and SO2 or NOx concentrations in the plume of the ship compared to the background. The measurements were performed from stations at land, from a boat, and from a helicopter. Mobile measurement platforms were found to have important advantages compared to the landbased ones because they allow to optimize the sampling conditions and to sample from ships on the open sea. Although optical methods can provide reliable results, it was found that at the state of the art, the "sniffer" approach is the most convenient technique for determining both SO2 and NOx emission factors remotely. The average random error on the determination of SO2 emission factors comparing two identical instrumental set-ups was 6%. However, it was found that apparently minor differences in the instrumental characteristics, such as response time, could cause significant differences between the emission factors determined. Direct stack measurements showed that about 14% of the fuel sulphur content was not emitted as SO2. This was supported by the remote measurements and is in agreement with the results of other field studies.

  14. Demonstration of selective catalytic reduction (SCR) technology for the control of nitrogen oxide (NOx) emissions from high-sulfur coal-fired boilers. Quarterly report No. 5, July--September 1991

    SciTech Connect

    Not Available

    1991-11-01

    The objective of this project is to demonstrate and evaluate commercially available Selective Catalytic Reduction (SCR) catalysts from US, Japanese and European catalyst suppliers on a high-sulfur US coal-fired boiler. SCR is a post-combustion nitrogen oxide (NO{sub x}) control technology that involves injecting ammonia into the flue gas generated from coal combustion in an electric utility boiler. The flue gas containing ammonia is then passed through a reactor that contains a specialized catalyst. In the presence of the catalyst, the ammonia reacts with NO{sub x} to convert it to nitrogen and water vapor.

  15. Quantification of variability and uncertainty in lawn and garden equipment NOx and total hydrocarbon emission factors.

    PubMed

    Frey, H Christopher; Bammi, Sachin

    2002-04-01

    Variability refers to real differences in emissions among multiple emission sources at any given time or over time for any individual emission source. Variability in emissions can be attributed to variation in fuel or feedstock composition, ambient temperature, design, maintenance, or operation. Uncertainty refers to lack of knowledge regarding the true value of emissions. Sources of uncertainty include small sample sizes, bias or imprecision in measurements, nonrepresentativeness, or lack of data. Quantitative methods for characterizing both variability and uncertainty are demonstrated and applied to case studies of emission factors for lawn and garden (L&G) equipment engines. Variability was quantified using empirical and parametric distributions. Bootstrap simulation was used to characterize confidence intervals for the fitted distributions. The 95% confidence intervals for the mean grams per brake horsepower/hour (g/hp-hr) emission factors for two-stroke engine total hydrocarbon (THC) and NOx emissions were from -30 to +41% and from -45 to +75%, respectively. The confidence intervals for four-stroke engines were from -33 to +46% for THCs and from -27 to +35% for NOx. These quantitative measures of uncertainty convey information regarding the quality of the emission factors and serve as a basis for calculation of uncertainty in emission inventories (EIs).

  16. Reduced emissions of CO2, NOx, and SO2 from U.S. power plants owing to switch from coal to natural gas with combined cycle technology

    NASA Astrophysics Data System (ADS)

    de Gouw, J. A.; Parrish, D. D.; Frost, G. J.; Trainer, M.

    2014-02-01

    Since 1997, an increasing fraction of electric power has been generated from natural gas in the United States. Here we use data from continuous emission monitoring systems (CEMS), which measure emissions at the stack of most U.S. electric power generation units, to investigate how this switch affected the emissions of CO2, NOx, and SO2. Per unit of energy produced, natural gas power plants equipped with combined cycle technology emit on an average 44% of the CO2 compared with coal power plants. As a result of the increased use of natural gas, CO2 emissions from U.S. fossil-fuel power plants were 23% lower in 2012 than they would have been if coal had continued to provide the same fraction of electric power as in 1997. In addition, natural gas power plants with combined cycle technology emit less NOx and far less SO2 per unit of energy produced than coal power plants. Therefore, the increased use of natural gas has led to emission reductions of NOx (40%) and SO2 (44%), in addition to those obtained from the implementation of emission control systems on coal power plants. These benefits to air quality and climate should be weighed against the increase in emissions of methane, volatile organic compounds, and other trace gases that are associated with the production, processing, storage, and transport of natural gas.

  17. Impact of Ship Emissions on Marine Boundary Layer NO(x) and SO2 Distributions over the Pacific Basin

    NASA Technical Reports Server (NTRS)

    Davis, D. D.; Grodzinsky, G.; Kasibhatla, P.; Crawford, J.; Chen, G.; Liu, S.; Bandy, A.; Thornton, D.; Guan, H.; Sandholm, S.

    2001-01-01

    The impact of ship emissions on marine boundary layer (MBL) NO(x) and SO2 levels over the Pacific Ocean has been explored by comparing predictions (with and without ships) from a global chemical transport model (GCTM) against compiled airborne observations of MBL NO(x) and SO2. For latitudes above 15 N, which define that part of the Pacific having the heaviest shipping, this analysis revealed significant model over prediction for NOx and a modest under prediction for SO2 when ship emissions were considered. Possible reasons for the difference in NO(x) and SO2 were explored using a full-chemistry box model. These results revealed that for an actual plume setting the NO(x) lifetime could be greatly shortened by chemical processes promoted by ship plume emissions themselves. Similar chemical behavior was not found for SO2.

  18. A new process for NOx reduction in combustion systems for the generation of energy from waste.

    PubMed

    Gohlke, Oliver; Weber, Toralf; Seguin, Philippe; Laborel, Yann

    2010-07-01

    In the EU, emissions from energy from waste plants are largely reduced by applying the Waste Incineration Directive with its limit of 200 mg/m3(s) for NO(x) emissions. The need for further improvement is reflected by new German legislation effective as of 27 January 2009, requiring 100 mg/m3(s). Other countries are expected to follow this example due to the national emission ceilings of the Gothenburg protocol and the concluding EU directive 2001/81/EC. On the other hand, an increase in energy efficiency will be encouraged by the EU Waste Framework Directive. This is why there is a need for new technologies that make it possible to reconcile both requirements: reduced emissions and increased energy efficiency. A new process combining the internal recirculation of flue gas with ammonia or urea injection in order to achieve less then 80 mg/m3(s) of NO(x) is described. Important additional features of the process are an R1 efficiency above the required 0.65 of the EU Waste Framework Directive even with standard steam parameters of 40 bar/380 degrees C as well as low ammonia slip in the flue gas at the boiler outlet of below 10 mg/m3(s).

  19. Effect of K loadings on nitrate formation/decomposition and on NOx storage performance of K-based NOx storage-reduction catalysts

    SciTech Connect

    Kim, Do Heui; Mudiyanselage, Kumudu K.; Szanyi, Janos; Kwak, Ja Hun; Zhu, Haiyang; Peden, Charles HF

    2013-10-25

    We have investigated nitrate formation and decomposition processes, and measured NOx storage performance on Pt-K2O/Al2O3 catalysts as a function of potassium loading. After NO2 adsorption at room temperature, ionic and bidentate nitrates were observed by fourier transform infra-red (FTIR) spectroscopy. The ratio of the former to the latter species increased with increasing potassium loading up to 10 wt%, and then stayed almost constant with additional K, demonstrating a clear dependence of loading on the morphology of the K species. Although both K2O(10)/Al2O3 and K2O(20)/Al2O3 samples have similar nitrate species after NO2 adsorption, the latter has more thermally stable nitrate species as evidenced by FTIR and NO2 temperature programmed desorption (TPD) results. With regard to NOx storage performance, the temperature of maximum NOx uptake (Tmax) is 573 K up to a potassium loading of 10 wt%. As the potassium loading increases from 10 wt% to 20 wt%, Tmax shifted from 573 K to 723 K. Moreover, the amount of NO uptake (38 cm3 NOx/g catal) at Tmax increased more than three times, indicating that efficiency of K in storing NOx is enhanced significantly at higher temperature, in good agreement with the NO2 TPD and FTIR results. Thus, a combination of characterization and NOx storage performance results demonstrates an unexpected effect of potassium loading on nitrate formation and decomposition processes; results important for developing Pt-K2O/Al2O3 for potential applications as high temperature NOx storage-reduction catalysts.

  20. 40 CFR 1042.820 - Emission standards and required emission reductions for remanufactured engines.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... under this subpart only if they have NOX emissions equivalent to or less than baseline NOX levels and PM... certified for locomotive engines under 40 CFR part 1033 may be deemed to also meet the requirements of this... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Emission standards and...

  1. Scenario analysis to vehicular emission reduction in Beijing-Tianjin-Hebei (BTH) region, China.

    PubMed

    Guo, Xiurui; Fu, Liwei; Ji, Muse; Lang, Jianlei; Chen, Dongsheng; Cheng, Shuiyuan

    2016-09-01

    Motor vehicle emissions are increasingly becoming one of the important factors affecting the urban air quality in China. It is necessary and useful to policy makers to demonstrate the situation given the relevant pollutants reduction measures are taken. This paper predicted the reduction potentials of conventional pollutants (PM10, NOx, CO, HC) under different control strategies and policies in the Beijing-Tianjin-Hebei (BTH) region during 2011-2020. There are the baseline and 5 control scenarios designed, which presented the different current and future possible vehicular emissions control measures. Future population of different kinds of vehicles were predicted based on the Gompertz model, and vehicle kilometers travelled estimated as well. After that, the emissions reduction under the different scenarios during 2011-2020 could be estimated using emission factors and activity level data. The results showed that, the vehicle population in the BTH region would continue to grow up, especially in Tianjin and Hebei. Comparing the different scenarios, emission standards updating scenario would achieve a substantial reduction and keep rising up for all the pollutants, and the scenario of eliminating high-emission vehicles can reduce emissions more effectively in short-term than in long-term, especially in Beijing. Due to the constraints of existing economical and technical level, the reduction effect of promoting new energy vehicles would not be significant, especially given the consideration of their lifetime impact. The reduction effect of population regulation scenario in Beijing cannot be ignorable and would keep going up for PM10, CO and HC, excluding NOx. Under the integrated scenario considering all the control measures it would achieve the maximum reduction potential of emissions, which means to reduce emissions of PM10, NOx, CO, HC, by 56%, 59%, 48%, 52%, respectively, compared to BAU scenario for the whole BTH region in 2020. PMID:27325548

  2. NOx Emissions from Oil and Gas Production in the North Sea

    NASA Astrophysics Data System (ADS)

    Lee, J. D.; Foulds, A.; Purvis, R.; Vaughan, A. R.; Carslaw, D.; Lewis, A. C.

    2015-12-01

    North Sea oil is a mixture of hydrocarbons, comprising liquid petroleum and natural gas, produced from petroleum reservoirs beneath the North Sea. As of January 2015, the North Sea is the world's most active offshore drilling region with 173 rigs drilling. During the summer of 2015, a series of survey flights took place on the UKs FAAM BAe 146 research aircraft with the primary aim to assess background methane (and other hydrocarbons) levels in the drilling areas of the North Sea. Also measured were Nitrogen Oxides (NO and NO2), which are emitted from almost all combustion processes and are a key air pollutant, both directly and as a precursor to ozone (O3). The oil and gas platforms in the North Sea are often manned and require significant power generation and support vessels for their continued operation, processes that potentially emit significant amounts of NOx into an otherwise relative clean environment. During these flights we were able to measure the NO­­­x (and any subsequently produced O3) emitted from specific rigs, as well as the NOx levels in the wider North Sea oil and gas production region (see figure for example). NOx mixing ratios of <10 ppbv were frequently observed in plumes, with significant perturbation to the wider North Sea background levels. NOx emissions from the rigs are point sources within the UKs National Atmospheric Emission Inventory (NAEI) and the measurements taken in plumes from individual rigs are used to assess the accuracy of these estimates.

  3. Impact of greenhouse gas emissions reduction in Indonesia: NO2

    NASA Astrophysics Data System (ADS)

    Susandi, A.

    2004-12-01

    In this study, we develop scenarios of total air pollution from fossil fuel consumption and its impacts for the 21st century, using an inter-temporal general equilibrium model MERGE. The Model for Evaluating the Regional and Global Effects of greenhouse gas reduction policies (MERGE) is used to project energy consumption and production. We use the base scenarios from IPCC (2000). These scenarios assume that no measures are undertaken to control greenhouse gas emissions. We extend the IPCC scenarios with mitigation scenarios, estimating the air pollution impacts of greenhouse gas emission reduction. The MERGE model was extended to analyze emissions of nitrogen dioxide (NO2), their concentrations, impacts on human health, and economic valuation. To estimate of nitrogen dioxide (NO2) impacts on respiratory symptoms, we calculated the NO2 concentration as derived from nitrogen oxide (NOx). In the baseline scenario, the concentrations of NO2 are rising to 2,263 μg/m3 in 2100. If the Organisation for Economic Co-operation and Development (OECD) countries reduce their emissions, respiratory symptoms among adult's associated with NO2 case would reach the highest to 65,741% of adult population cases by the end of century. If all countries reduce their emission in the future, the total health problem cost associated with NO2 will lower 35% of GDP than in the baseline scenario during the century.

  4. High ozone concentrations on hot days: The role of electric power demand and NOx emissions

    NASA Astrophysics Data System (ADS)

    He, Hao; Hembeck, Linda; Hosley, Kyle M.; Canty, Timothy P.; Salawitch, Ross J.; Dickerson, Russell R.

    2013-10-01

    ambient temperatures intensify photochemical production of tropospheric ozone, leading to concerns that global warming may exacerbate smog episodes. This widely observed phenomenon has been termed the climate penalty factor (CPF). A variety of meteorological and photochemical processes have been suggested to explain why surface ozone increases on hot days. Here, we quantify an anthropogenic factor previously overlooked: the rise of ozone precursor emissions on hot summer days due to high electricity demand. Between 1997 and 2011, power plant emissions of NOx in the eastern U.S. increased by ~2.5-4.0%/°C, raising surface NOx concentrations by 0.10-0.25 ppb/°C. Given an ozone production efficiency (OPE) of ~8 mol/mol based on the 2011 NASA DISCOVER-AQ campaign, at least one third of the CPF observed in the eastern U.S. can be attributed to the temperature dependence of NOx emissions. This finding suggests that controlling emissions associated with electricity generation on hot summer days can mitigate the CPF.

  5. Recent advances in automotive catalysis for NOx emission control by small-pore microporous materials

    SciTech Connect

    Beale, Andrew M.; Gao, Feng; Lezcano-Gonzalez, Ines; Peden, Charles HF; Szanyi, Janos

    2015-10-05

    The ever increasing demand to develop highly fuel efficient engines coincides with the need to minimize air pollution originating from the exhaust gases of internal combustion engines. Dramatically improved fuel efficiency can be achieved at air-to-fuel ratios much higher than stoichiometric. In the presence of oxygen in large excess, however, traditional three-way catalysts are unable to reduce NOx. Among the number of lean-NOx reduction technologies, selective catalytic reduction (SCR) of NOx by NH3 over Cu- and Fe-ion exchanged zeolite catalysts has been extensively studied over the past 30+ years. Despite the significant advances in developing a viable practical zeolite-based catalyst for lean NOx reduction, the insufficient hydrothermal stabilities of the zeolite structures considered cast doubts about their real-world applicability. During the past decade a renewed interest in zeolite-based lean NOx reduction was spurred by the discovery of the very high activity of Cu-SSZ-13 (and the isostructural Cu-SAPO-34) in the NH3 SCR of NOx. These new, small-pore zeolite-based catalysts not only exhibited very high NOx conversion and N2 selectivity, but also exhibited exceptional high hydrothermal stability at high temperatures. In this review we summarize the key discoveries of the past ~5 years that lead to the introduction of these catalysts into practical application. The review first briefly discusses the structure and preparation of the CHA structure-based zeolite catalysts, and then summarizes the key learnings of the rather extensive (but not complete) characterisation work. Then we summarize the key findings of reaction kinetics studies, and provide some mechanistic details emerging from these investigations. At the end of the review we highlight some of the issues that are still need to be addressed in automotive exhaust control catalysis. Funding A.M.B. and I.L.G. would like to thank EPSRC for funding. F.G., C.H.F.P. and J.Sz. gratefully acknowledge

  6. The use of rice hulls for sustainable control of NOx emissions in deep space missions

    NASA Technical Reports Server (NTRS)

    Xu, X. H.; Shi, Y.; Kwak, D.; Chang, S. G.; Fisher, J. W.; Pisharody, S.; Moran, M. J.; Wignarajah, K.

    2003-01-01

    The use of the activated carbon produced from rice hulls to control NOx emissions for future deep space missions has been demonstrated. The optimal carbonization temperature range was found to be between 600 and 750 degrees C. A burnoff of 61.8% was found at 700 degrees C in pyrolysis and 750 degrees C in activation. The BET surface area of the activated carbon from rice hulls was determined to be 172 m2/g when prepared at 700 degrees C. The presence of oxygen in flue gas is essential for effective adsorption of NO by activated carbon. On the contrary, water vapor inhibits the adsorption efficiency of NO. Consequently, water vapor in flue gas should be removed by drying agents before adsorption to ensure high NO adsorption efficiency. All of the NO in the flue gas was removed for more than 1.5 h when 10% oxygen was present and the ratio of the carbon weight to the flue gas flow rate (W/F) was 15.4 g min/L. Reduction of the adsorbed NO to form N2 could be effectively accomplished under anaerobic conditions at 550 degrees C. The adsorption capacity of NO on the activated carbon was found to be 5.02 mg of NO/g of carbon. The loss of carbon mass was determined to be about 0.16% of the activated carbon per cycle of regeneration if the regeneration occurred when the NO in the flue gas after the carbon bed reached 4.8 ppm, the space maximum allowable concentration. The reduction of the adsorbed NO also regenerated the activated carbon, and the regenerated activated carbon exhibited an improved NO adsorption efficiency.

  7. High-Potential Electrocatalytic O2 Reduction with Nitroxyl / NOx Mediators: Implications for Fuel Cells and Aerobic Oxidation Catalysis

    SciTech Connect

    Gerken, James B.; Stahl, Shannon S.

    2015-07-15

    Efficient reduction of O2 to water is a central challenge in energy conversion and aerobic oxidation catalysis. In the present study, we investigate the electrochemical reduction of O2 with soluble organic nitroxyl and nitrogen oxide (NOx) mediators. When used alone, neither organic nitroxyls, such as TEMPO (2,2,6,6-tetramethyl-1-piperidinyl-N-oxyl), nor NOx species, such as sodium nitrite, are effective mediators of electrochemical O2 reduction. The combination of nitroxyl/NOx species, however, mediates sustained O2 reduction at electrochemical potentials of 0.19–0.33 V (vs. Fc/Fc+) in acetonitrile containing trifluoroacetic acid. Mechanistic analysis of the coupled redox reactions supports a process in which the nitrogen oxide catalyst drives aerobic oxidation of a nitroxyl mediator to an oxoammonium species, which then is reduced back to the nitroxyl at the cathode. The electrolysis potential is dictated by the oxoammonium/nitroxyl reduction potential. The high potentials observed with this ORR system benefit from the mechanism-based specificity for four-electron reduction of oxygen to water mediated by NOx species, together with kinetically efficient reduction of oxidized NOx species by TEMPO and other organic nitroxyls. This research was supported as part of the Center for Molecular Electrocatalysis, an Energy Frontier Research Center, funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences.

  8. Improving combustion characteristics and NO(x) emissions of a down-fired 350 MW(e) utility boiler with multiple injection and multiple staging.

    PubMed

    Kuang, Min; Li, Zhengqi; Xu, Shantian; Zhu, Qunyi

    2011-04-15

    Within a Mitsui Babcock Energy Limited down-fired pulverized-coal 350 MW(e) utility boiler, in situ experiments were performed, with measurements taken of gas temperatures in the burner and near the right-wall regions, and of gas concentrations (O(2) and NO) from the near-wall region. Large combustion differences between zones near the front and rear walls and particularly high NO(x) emissions were found in the boiler. With focus on minimizing these problems, a new technology based on multiple-injection and multiple-staging has been developed. Combustion improvements and NO(x) reductions were validated by investigating three aspects. First, numerical simulations of the pulverized-coal combustion process and NO(x) emissions were compared in both the original and new technologies. Good agreement was found between simulations and in situ measurements with the original technology. Second, with the new technology, gas temperature and concentration distributions were found to be symmetric near the front and rear walls. A relatively low-temperature and high-oxygen-concentration zone formed in the near-wall region that helps mitigate slagging in the lower furnace. Third, NO(x) emissions were found to have decreased by as much as 50%, yielding a slight decrease in the levels of unburnt carbon in the fly ash.

  9. SUMMARY REPORT CONTROL OF NOX EMISSIONS BY REBURNING

    EPA Science Inventory

    This report covers NOx control employing reburning technology: A new, effective method of controlling NOx emissions from a wide range of stationary combustion sources including large, coal-fired, utility boilers. Although reburning potentially is applicable ...

  10. Attempts to Reduce NOx Exhaust Emissions by Using Reformulated Biodiesel

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Two routes were investigated for reformulating soy-based biodiesel in an effort to reduce its nitrogen oxide emissions. In the first approach, methyl soyate was modified by converting a proportion of the cis-bonds in the fatty acid chains of its methyl esters to their trans isomers. In the second ...

  11. Method for reducing CO2, CO, NOX, and SOx emissions

    DOEpatents

    Lee, James Weifu; Li, Rongfu

    2002-01-01

    Industrial combustion facilities are integrated with greenhouse gas-solidifying fertilizer production reactions so that CO.sub.2, CO, NO.sub.x, and SO.sub.x emissions can be converted prior to emission into carbonate-containing fertilizers, mainly NH.sub.4 HCO.sub.3 and/or (NH.sub.2).sub.2 CO, plus a small fraction of NH.sub.4 NO.sub.3 and (NH.sub.4).sub.2 SO.sub.4. The invention enhances sequestration of CO.sub.2 into soil and the earth subsurface, reduces N0.sub.3.sup.- contamination of surface and groundwater, and stimulates photosynthetic fixation of CO.sub.2 from the atmosphere. The method for converting CO.sub.2, CO, NO.sub.x, and SO.sub.x emissions into fertilizers includes the step of collecting these materials from the emissions of industrial combustion facilities such as fossil fuel-powered energy sources and transporting the emissions to a reactor. In the reactor, the CO.sub.2, CO, N.sub.2, SO.sub.x, and/or NO.sub.x are converted into carbonate-containing fertilizers using H.sub.2, CH.sub.4, or NH.sub.3. The carbonate-containing fertilizers are then applied to soil and green plants to (1) sequester inorganic carbon into soil and subsoil earth layers by enhanced carbonation of groundwater and the earth minerals, (2) reduce the environmental problem of NO.sub.3.sup.- runoff by substituting for ammonium nitrate fertilizer, and (3) stimulate photosynthetic fixation of CO.sub.2 from the atmosphere by the fertilization effect of the carbonate-containing fertilizers.

  12. The contribution of soil biogenic NO and HONO emissions from a managed hyperarid ecosystem to the regional NOx emissions during growing season

    NASA Astrophysics Data System (ADS)

    Mamtimin, Buhalqem; Meixner, Franz X.; Behrendt, Thomas; Badawy, Moawad; Wagner, Thomas

    2016-08-01

    A study was carried out to understand the contributions of soil biogenic NO emissions from managed (fertilized and irrigated) hyperarid ecosystems in NW China to the regional NOx emissions during the growing season. Soil biogenic net potential NO fluxes were quantified by laboratory incubation of soil samples from the three dominating ecosystems (desert, cotton, and grape fields). Regional biogenic NO emissions were calculated bottom-up hourly for the entire growing season (April-September 2010) by considering corresponding land use, hourly data of soil temperature, gravimetric soil moisture, and fertilizer enhancement factors. The regional HONO emissions were estimated using the ratio of the optimum condition ((FN,opt(HONO) to FN,opt (NO)). Regional anthropogenic NOx emissions were calculated bottom-up from annual statistical data provided by regional and local government bureaus which have been downscaled to monthly value. Regional top-down emission estimates of NOx were derived on the monthly basis from satellite observations (OMI) of tropospheric vertical NO2 column densities and prescribed values of the tropospheric NOx lifetime. In order to compare the top-down and bottom-up emission estimates, all emission estimates were expressed in terms of mass of atomic nitrogen. Consequently, monthly top-down NOx emissions (total) were compared with monthly bottom-up NOx emissions (biogenic + anthropogenic) for the time of the satellite overpass (around 13:00 LT) with the consideration of the diurnal cycle of bottom-up estimates. Annual variation in total Tohsun Oasis NOx emissions is characterized by a strong peak in winter (December-February) and a secondary peak in summer (June-August). During summer, soil biogenic emissions were from equal to double that of related anthropogenic emissions, and grape soils were the main contributor to soil biogenic emissions, followed by cotton soils, while emissions from the desert were negligible. The top-down and bottom

  13. Cold-Start Emissions Control in Hybrid Vehicles Equipped with a Passive Hydrocarbon and NOx Adsorber

    SciTech Connect

    Gao, Zhiming; Kim, Miyoung; Choi, Jae-Soon; Daw, C Stuart; Parks, II, James E; Smith, David E

    2012-01-01

    We presents a study of the potential for using low-cost sorbent materials (i.e. Ag-Beta-zeolite and Fe-Mn-Zr transition metal oxides) to temporally trap hydrocarbons (HCs) and nitrogen oxides (NOx) emissions during cold-start periods in HEVs and PHEVs over transient driving cycles. The adsorption behavior of the candidate sorbent materials was characterized in our laboratory flow reactor experiments. The parameters were then used to develop a one-dimensional, transient device model which has been implemented in the Powertrain Systems Analysis Toolkit (PSAT) to simulate a passive HC and NOx absorber device. The results show that such an absorber can substantially reduce HC and NOx emissions by storing them when the 3-way catalyst is too cool to function and re-releasing them when the exhaust temperature rises. These improved emission controls do not involve any penalty in fuel consumption or require any change in engine operation. The cost of these sorbent materials is also much less than conventional 3-way catalysts.

  14. Improved NOx emissions and combustion characteristics for a retrofitted down-fired 300-MWe utility boiler.

    PubMed

    Li, Zhengqi; Ren, Feng; Chen, Zhichao; Liu, Guangkui; Xu, Zhenxing

    2010-05-15

    A new technique combining high boiler efficiency and low-NO(x) emissions was employed in a 300MWe down-fired boiler as an economical means to reduce NO(x) emissions in down-fired boilers burning low-volatile coals. Experiments were conducted on this boiler after the retrofit with measurements taken of gas temperature distributions along the primary air and coal mixture flows and in the furnace, furnace temperatures along the main axis and gas concentrations such as O(2), CO and NO(x) in the near-wall region. Data were compared with those obtained before the retrofit and verified that by applying the combined technique, gas temperature distributions in the furnace become more reasonable. Peak temperatures were lowered from the upper furnace to the lower furnace and flame stability was improved. Despite burning low-volatile coals, NO(x) emissions can be lowered by as much as 50% without increasing the levels of unburnt carbon in fly ash and reducing boiler thermal efficiency.

  15. High-Potential Electrocatalytic O2 Reduction with Nitroxyl/NOx Mediators: Implications for Fuel Cells and Aerobic Oxidation Catalysis

    PubMed Central

    2015-01-01

    Efficient reduction of O2 to water is a central challenge in energy conversion and many aerobic oxidation reactions. Here, we show that the electrochemical oxygen reduction reaction (ORR) can be achieved at high potentials by using soluble organic nitroxyl and nitrogen oxide (NOx) mediators. When used alone, neither organic nitroxyls, such as 2,2,6,6-tetramethyl-1-piperidinyl-N-oxyl (TEMPO), nor NOx species, such as sodium nitrite, are effective ORR mediators. The combination of nitroxyl/NOx species, however, mediates sustained O2 reduction with overpotentials as low as 300 mV in acetonitrile containing trifluoroacetic acid. Mechanistic analysis of the coupled redox reactions supports a process in which the nitrogen oxide catalyst drives aerobic oxidation of a nitroxyl mediator to an oxoammonium species, which then is reduced back to the nitroxyl at the cathode. The electrolysis potential is dictated by the oxoammonium/nitroxyl reduction potential. The overpotentials accessible with this ORR system are significantly lower than widely studied molecular metal-macrocycle ORR catalysts and benefit from the mechanism-based specificity for four-electron reduction of oxygen to water mediated by NOx species, together with kinetically efficient reduction of oxidized NOx species by TEMPO and other organic nitroxyls. PMID:27162977

  16. Ammonia-Free NOx Control System

    SciTech Connect

    Song Wu; Zhen Fan; Andrew H. Seltzer; Richard G. Herman

    2005-03-31

    Research is being conducted under United States Department of Energy (DOE) Contract DE-FC26-03NT41865 to develop a new technology to achieve very low levels of NOx emissions from pulverized coal fired boiler systems by employing a novel system level integration between the PC combustion process and the catalytic NOx reduction with CO present in the combustion flue gas. The combustor design and operating conditions will be optimized to achieve atypical flue gas conditions. This approach will not only suppress NOx generation during combustion but also further reduce NOx over a downstream catalytic reactor that does not require addition of an external reductant, such as ammonia.

  17. Ammonia-Free NOx Control System

    SciTech Connect

    Song Wu; Zhen Fan; Andrew H. Seltzer

    2005-06-30

    Research is being conducted under United States Department of Energy (DOE) Contract DEFC26-03NT41865 to develop a new technology to achieve very low levels of NOx emissions from pulverized coal fired boiler systems by employing a novel system level integration between the PC combustion process and the catalytic NOx reduction with CO present in the combustion flue gas. The combustor design and operating conditions will be optimized to achieve atypical flue gas conditions. This approach will not only suppress NOx generation during combustion but also further reduce NOx over a downstream catalytic reactor that does not require addition of an external reductant, such as ammonia.

  18. Quantifying the air pollutants emission reduction during the 2008 Olympic games in Beijing.

    PubMed

    Wang, Shuxiao; Zhao, Meng; Xing, Jia; Wu, Ye; Zhou, Yu; Lei, Yu; He, Kebin; Fu, Lixin; Hao, Jiming

    2010-04-01

    Air quality was a vital concern for the Beijing Olympic Games in 2008. To strictly control air pollutant emissions and ensure good air quality for the Games, Beijing municipal government announced an "Air Quality Guarantee Plan for the 29th Olympics in Beijing". In order to evaluate the effectiveness of the guarantee plan, this study analyzed the air pollutant emission reductions during the 29th Olympiad in Beijing. In June 2008, daily emissions of SO(2), NO(X), PM(10), and NMVOC in Beijing were 103.9 t, 428.5 t, 362.7 t, and 890.0 t, respectively. During the Olympic Games, the daily emissions of SO(2), NO(X), PM(10), and NMVOC in Beijing were reduced to 61.6 t, 229.1 t, 164.3 t, and 381.8 t -41%, 47%, 55%, and 57% lower than June 2008 emission levels. Closing facilities producing construction materials reduced the sector's SO(2) emissions by 85%. Emission control measures for mobile sources, including high-emitting vehicle restrictions, government vehicle use controls, and alternate day driving rules for Beijing's 3.3 million private cars, reduced mobile source NO(X) and NMVOC by 46% and 57%, respectively. Prohibitions on building construction reduced the sector's PM(10) emissions by approximately 90% or total PM(10) by 35%. NMVOC reductions came mainly from mobile source and fugitive emission reductions. Based on the emission inventories developed in this study, the CMAQ model was used to simulate Beijing's ambient air quality during the Olympic Games. The model results accurately reflect the environmental monitoring data providing evidence that the emission inventories in this study are reasonably accurate and quantitatively reflect the emission changes attributable to air pollution control measures taken during the 29th Olympic Games in 2008. PMID:20222727

  19. Bridge-based sensing of NOx and SO2 emissions from ocean-going ships

    NASA Astrophysics Data System (ADS)

    Burgard, Daniel A.; Bria, Carmen R. M.

    2016-07-01

    As emissions from nonroad mobile sources face increased regulatory scrutiny, a surprisingly few number of real-world, in-use measurements exist for these sources. This paper reports the first use of an open-path Remote Sensing Device (RSD) to measure emissions from ocean-going ships, including cruise ships. This noninvasive technique measured NOx and SO2 emission factors from 16 individually identified ocean-going ships as they passed under the Lions Gate Bridge in Vancouver, B.C. and their exhaust plumes passed through the sensing beam of the RSD on a bridge directly above. Ship NOx emissions generally agreed with previous studies showing no emissions trends across vessel type. Ship SO2 emissions were reasonable based on expected Environmental Control Area fuel sulfur requirements and corresponded to 0.4-2.4% sulfur in the fuels. This method's specificity of individual vessel SO2 measurements suggests that this technique could be used as a tool to detect high sulfur fuel use in vessels.

  20. Combining support vector regression and ant colony optimization to reduce NOx emissions in coal-fired utility boilers

    SciTech Connect

    Ligang Zheng; Hao Zhou; Chunlin Wang; Kefa Cen

    2008-03-15

    Combustion optimization has recently demonstrated its potential to reduce NOx emissions in high capacity coal-fired utility boilers. In the present study, support vector regression (SVR), as well as artificial neural networks (ANN), was proposed to model the relationship between NOx emissions and operating parameters of a 300 MW coal-fired utility boiler. The predicted NOx emissions from the SVR model, by comparing with that of the ANN-based model, showed better agreement with the values obtained in the experimental tests on this boiler operated at different loads and various other operating parameters. The mean modeling error and the correlation factor were 1.58% and 0.94, respectively. Then, the combination of the SVR model with ant colony optimization (ACO) to reduce NOx emissions was presented in detail. The experimental results showed that the proposed approach can effectively reduce NOx emissions from the coal-fired utility boiler by about 18.69% (65 ppm). A time period of less than 6 min was required for NOx emissions modeling, and 2 min was required for a run of optimization under a PC system. The computing times are suitable for the online application of the proposed method to actual power plants. 37 refs., 8 figs., 3 tabs.

  1. Cermet Filters for Diesel Engine Emissions Reduction

    SciTech Connect

    Kong, Peter Chuen Sun

    2001-08-01

    Pollution from diesel engines is a significant part of our nation's air-quality problem. Even under the more stringent standards for heavy-duty engines set to take effect in 2004, these engines will continue to emit large amounts of nitrogen oxides and particulate matter, both of which affect public health. To address this problem, the Idaho National Engineering and Environmental Laboratory (INEEL) invented a self-cleaning, high temperature, cermet filter that reduces heavy-duty diesel engine emissions. The main advantage of the INEEL cermet filter, compared to current technology, is its ability to destroy carbon particles and NOx in diesel engine exhaust. As a result, this technology is expected to improve our nation's environmental quality by meeting the need for heavy-duty diesel engine emissions control. This paper describes the cermet filter technology and the initial research and development effort.

  2. Methodology for Airborne Quantification of NOx fluxes over Central London and Comparison to Emission Inventories

    NASA Astrophysics Data System (ADS)

    Vaughan, A. R.; Lee, J. D.; Lewis, A. C.; Purvis, R.; Carslaw, D.; Misztal, P. K.; Metzger, S.; Beevers, S.; Goldstein, A. H.; Hewitt, C. N.; Shaw, M.; Karl, T.; Davison, B.

    2015-12-01

    The emission of pollutants is a major problem in today's cities. Emission inventories are a key tool for air quality management, with the United Kingdom's National and London Atmospheric Emission Inventories (NAEI & LAEI) being good examples. Assessing the validity of such inventoried is important. Here we report on the technical methodology of matching flux measurements of NOx over a city to inventory estimates. We used an eddy covariance technique to directly measure NOx fluxes from central London on an aircraft flown at low altitude. NOx mixing ratios were measured at 10 Hz time resolution using chemiluminescence (to measure NO) and highly specific photolytic conversion of NO2 to NO (to measure NO2). Wavelet transformation was used to calculate instantaneous fluxes along the flight track for each flight leg. The transformation allows for both frequency and time information to be extracted from a signal, where we quantify the covariance between the de-trended vertical wind and concentration to derive a flux. Comparison between the calculated fluxes and emission inventory data was achieved using a footprint model, which accounts for contributing source. Using both a backwards lagrangian model and cross-wind dispersion function, we find the footprint extent ranges from 5 to 11 Km in distance from the sample point. We then calculate a relative weighting matrix for each emission inventory within the calculated footprint. The inventories are split into their contributing source sectors with each scaled using up to date emission factors, giving a month; day and hourly scaled estimate which is then compared to the measurement.

  3. Comparison of Anthropogenic CO2, NOx, and CO Emissions: Exploiting a Synergy Between Air Quality and Carbon Cycle Studies

    NASA Astrophysics Data System (ADS)

    Fischer, M. L.; Gurney, K. R.; Gregg, J. S.; Murtishaw, S.; Knox, S.; Andres, R. J.; Sieb, B.

    2005-05-01

    Studies of biospheric CO2 exchange at the regional to continental scale would be facilitated by spatiotemporally resolved estimates of CO2 emissions from fossil fuel combustion and other human activities. However, current estimates of fossil CO2 emissions do not provide sufficient temporal or spatial resolution for regional-scale investigations. The US-EPA National Emission Inventory (NEI) for criteria pollutants (e.g., NOx and CO) was developed for control of regional air quality and currently provides high resolution emissions estimates that are based, in part on, estimates of fuel consumption. Here we investigate the applicability of estimating CO2 emissions from either 1) NEI estimates of NOx or CO emissions, or 2) underlying information on fuel use contained within NEI. First, we calculate monthly sums of NOx and CO emissions separately for mobile, distributed area, and point sources for the 48 continental United States. We compare the aggregate NOx and CO emissions with monthly sums of each states CO2 emissions computed from sales of petroleum, natural gas, and coal as reported by the US Energy Information Agency (EIA). We then compute linear regressions to estimate CO:CO2 and NOx:CO2 emissions ratios and quantify the fraction of variance in CO2 captured by NOx and CO. Although the categories in the two data sets do not overlap perfectly, we find that in the cases where a close correspondence between fuel type and use is expected (e.g., petroleum and mobile sources), variations in NOx and CO explain approximately 80% of the variation in CO2 emissions. Second, we employ the Consolidated Community Emissions Processing Tool (CONCEPT) framework to extract estimates of fuel use or other proxy variables and estimate CO2 directly from the information contained in the NEI, and compare with the EIA estimates of CO2 emissions, and with NEI estimates of NOx and CO emissions as above. Finally, we discuss these results with consideration of previous atmospheric

  4. Comparison of Anthropogenic CO2, NOx, and CO Emissions: Exploiting a Synergy Between Air Quality and Carbon Cycle Studies

    NASA Astrophysics Data System (ADS)

    Fischer, M. L.; Gurney, K. R.; Gregg, J. S.; Murtishaw, S.; Knox, S.; Andres, R. J.; Sieb, B.

    2006-12-01

    Studies of biospheric CO2 exchange at the regional to continental scale would be facilitated by spatiotemporally resolved estimates of CO2 emissions from fossil fuel combustion and other human activities. However, current estimates of fossil CO2 emissions do not provide sufficient temporal or spatial resolution for regional-scale investigations. The US-EPA National Emission Inventory (NEI) for criteria pollutants (e.g., NOx and CO) was developed for control of regional air quality and currently provides high resolution emissions estimates that are based, in part on, estimates of fuel consumption. Here we investigate the applicability of estimating CO2 emissions from either 1) NEI estimates of NOx or CO emissions, or 2) underlying information on fuel use contained within NEI. First, we calculate monthly sums of NOx and CO emissions separately for mobile, distributed area, and point sources for the 48 continental United States. We compare the aggregate NOx and CO emissions with monthly sums of each states CO2 emissions computed from sales of petroleum, natural gas, and coal as reported by the US Energy Information Agency (EIA). We then compute linear regressions to estimate CO:CO2 and NOx:CO2 emissions ratios and quantify the fraction of variance in CO2 captured by NOx and CO. Although the categories in the two data sets do not overlap perfectly, we find that in the cases where a close correspondence between fuel type and use is expected (e.g., petroleum and mobile sources), variations in NOx and CO explain approximately 80% of the variation in CO2 emissions. Second, we employ the Consolidated Community Emissions Processing Tool (CONCEPT) framework to extract estimates of fuel use or other proxy variables and estimate CO2 directly from the information contained in the NEI, and compare with the EIA estimates of CO2 emissions, and with NEI estimates of NOx and CO emissions as above. Finally, we discuss these results with consideration of previous atmospheric

  5. Global Partitioning of NOx Sources Using Satellite Observations: Relative Roles of Fossil Fuel Combustion, Biomass Burning and Soil Emissions

    NASA Technical Reports Server (NTRS)

    Jaegle, Lyatt; Steinberger, Linda; Martin, Randall V.; Chance, Kelly

    2005-01-01

    This document contains the following abstract for the paper "Global partitioning of NOx sources using satellite observations: Relative roles of fossil fuel combustion, biomass burning and soil emissions." Satellite observations have been used to provide important new information about emissions of nitrogen oxides. Nitrogen oxides (NOx) are significant in atmospheric chemistry, having a role in ozone air pollution, acid deposition and climate change. We know that human activities have led to a three- to six-fold increase in NOx emissions since pre-industrial times, and that there are three main surface sources of NOx: fuel combustion, large-scale fires, and microbial soil processes. How each of these sources contributes to the total NOx emissions is subject to some doubt, however. The problem is that current NOx emission inventories rely on bottom-up approaches, compiling large quantities of statistical information from diverse sources such as fuel and land use, agricultural data, and estimates of burned areas. This results in inherently large uncertainties. To overcome this, Lyatt Jaegle and colleagues from the University of Washington, USA, used new satellite observations from the Global Ozone Monitoring Experiment (GOME) instrument. As the spatial and seasonal distribution of each of the sources of NOx can be clearly mapped from space, the team could provide independent topdown constraints on the individual strengths of NOx sources, and thus help resolve discrepancies in existing inventories. Jaegle's analysis of the satellite observations, presented at the recent Faraday Discussion on "Atmospheric Chemistry", shows that fuel combustion dominates emissions at northern mid-latitudes, while fires are a significant source in the Tropics. Additionally, she discovered a larger than expected role for soil emissions, especially over agricultural regions with heavy fertilizer use. Additional information is included in the original extended abstract.

  6. Experimental study on combustion characteristics and NOX emissions of pulverized anthracite preheated by circulating fluidized bed

    NASA Astrophysics Data System (ADS)

    Wang, Jun; Zhu, Jian-Guo; Lu, Qing-Gang

    2011-08-01

    A 30 kW bench-scale rig of pulverized anthracite combustion preheated by a circulating fluidized bed (CFB) was developed. The CFB riser has a diameter of 90 mm and a height of 1,500 mm. The down-fired combustion chamber (DFCC) has a diameter of 260 mm and a height of 3,000 mm. Combustion experiments were carried out using pulverized anthracite with 6.74% volatile content. This low volatile coal is difficult to ignite and burn out. Therefore, it requires longer burnout time and higher combustion temperature, which results in larger NOX emissions. In the current study, important factors that influence the combustion characteristics and NOX emissions were investigated such as excess air ratio, air ratio in the reducing zone, and fuel residence time in the reducing zone. Pulverized anthracite can be quickly preheated up to 800°C in CFB when the primary air is 24% of theoretical air for combustion, and the temperature profile is uniform in DFCC. The combustion efficiency is 94.2%, which is competitive with other anthracite combustion technologies. When the excess air ratio ranges from 1.26 to 1.67, the coal-N conversion ratio is less than 32% and the NOX emission concentration is less than 371 mg/m3 (@6% O2). When the air ratio in the reducing zone is 0.12, the NOX concentration is 221 mg/m3 (@6% O2), and the coal-N conversion ratio is 21%, which is much lower than that of other boilers.

  7. Variability in operation-based NO(x) emission factors with different test routes, and its effects on the real-driving emissions of light diesel vehicles.

    PubMed

    Lee, Taewoo; Park, Junhong; Kwon, Sangil; Lee, Jongtae; Kim, Jeongsoo

    2013-09-01

    The objective of this study is to quantify the differences in NO(x) emissions between standard and non-standard driving and vehicle operating conditions, and to estimate by how much NO(x) emissions exceed the legislative emission limits under typical Korean road traffic conditions. Twelve Euro 3-5 light-duty diesel vehicles (LDDVs) manufactured in Korea were driven on a chassis dynamometer over the standard New European Driving Cycle (NEDC) and a representative Korean on-road driving cycle (KDC). NO(x) emissions, average speeds and accelerations were calculated for each 1-km trip segment, so called averaging windows. The results suggest that the NO(x) emissions of the tested vehicles are more susceptible to variations in the driving cycles than to those in the operating conditions. Even under comparable operating conditions, the NO(x) control capabilities of vehicles differ from each other, i.e., NO(x) control is weaker for the KDC than for the NEDC. The NO(x) emissions over the KDC for given vehicle operating conditions exceed those over the NEDC by more than a factor of 8. Consequently, on-road NO(x) emission factors are estimated here to exceed the Euro 5 emission limit by up to a factor of 8, 4 and 3 for typical Korean urban, rural, and motorway road traffic conditions, respectively. Our findings support the development of technical regulations for supplementary real-world emission tests for emission certification and the corresponding research actions taken by automotive industries. PMID:23747552

  8. 40 CFR 75.17 - Specific provisions for monitoring emissions from common, bypass, and multiple stacks for NOX...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... emissions from common, bypass, and multiple stacks for NOX emission rate. 75.17 Section 75.17 Protection of... MONITORING Monitoring Provisions § 75.17 Specific provisions for monitoring emissions from common, bypass... § 75.17(d) for units with bypass stacks. Further, this option shall not be used unless the...

  9. Analysis of long-term observations of NOx and CO in megacities and application to constraining emissions inventories

    NASA Astrophysics Data System (ADS)

    Hassler, Birgit; McDonald, Brian C.; Frost, Gregory J.; Borbon, Agnes; Carslaw, David C.; Civerolo, Kevin; Granier, Claire; Monks, Paul S.; Monks, Sarah; Parrish, David D.; Pollack, Ilana B.; Rosenlof, Karen H.; Ryerson, Thomas B.; Schneidemesser, Erika; Trainer, Michael

    2016-09-01

    Long-term atmospheric NOx/CO enhancement ratios in megacities provide evaluations of emission inventories. A fuel-based emission inventory approach that diverges from conventional bottom-up inventory methods explains 1970-2015 trends in NOx/CO enhancement ratios in Los Angeles. Combining this comparison with similar measurements in other U.S. cities demonstrates that motor vehicle emissions controls were largely responsible for U.S. urban NOx/CO trends in the past half century. Differing NOx/CO enhancement ratio trends in U.S. and European cities over the past 25 years highlights alternative strategies for mitigating transportation emissions, reflecting Europe's increased use of light-duty diesel vehicles and correspondingly slower decreases in NOx emissions compared to the U.S. A global inventory widely used by global chemistry models fails to capture these long-term trends and regional differences in U.S. and Europe megacity NOx/CO enhancement ratios, possibly contributing to these models' inability to accurately reproduce observed long-term changes in tropospheric ozone.

  10. Diesel NO(x) aftertreatment by combined process using temperature swing adsorption, NO(x) reduction by nonthermal plasma, and NO(x) recirculation: improvement of the recirculation process.

    PubMed

    Yoshida, Keiichiro; Kuwahara, Takuya; Kuroki, Tomoyuki; Okubo, Masaaki

    2012-09-15

    NO(x) emitted from a stationary diesel engine generator was treated with a hybrid system comprising NO(x) reduction by nonthermal plasma (NTP) and temperature swing adsorption (TSA) driven by engine waste heat. TSA produces a low-volume gas mixture of N(2) and highly concentrated NO(x), which is effectively reduced by NTP treatment. Improved treatment performance and efficiency are achieved by re-injecting the NTP-treated gas mixture into the engine intake. The system comprises two switchable adsorption chambers; the operation of this system was simulated by using a one-chamber system. The maximum energy efficiency for NO(x) treatment is 200 g(NO(2))/kWh. The respective contributions of NTP and injection of N(2) and NO(x) to the performance were theoretically analyzed. The analysis predicts that high energy efficiency and high NO(x)-removal efficiency can be simultaneously achieved with this system but miniaturization of the adsorption chambers will be a challenge.

  11. Diesel NO(x) aftertreatment by combined process using temperature swing adsorption, NO(x) reduction by nonthermal plasma, and NO(x) recirculation: improvement of the recirculation process.

    PubMed

    Yoshida, Keiichiro; Kuwahara, Takuya; Kuroki, Tomoyuki; Okubo, Masaaki

    2012-09-15

    NO(x) emitted from a stationary diesel engine generator was treated with a hybrid system comprising NO(x) reduction by nonthermal plasma (NTP) and temperature swing adsorption (TSA) driven by engine waste heat. TSA produces a low-volume gas mixture of N(2) and highly concentrated NO(x), which is effectively reduced by NTP treatment. Improved treatment performance and efficiency are achieved by re-injecting the NTP-treated gas mixture into the engine intake. The system comprises two switchable adsorption chambers; the operation of this system was simulated by using a one-chamber system. The maximum energy efficiency for NO(x) treatment is 200 g(NO(2))/kWh. The respective contributions of NTP and injection of N(2) and NO(x) to the performance were theoretically analyzed. The analysis predicts that high energy efficiency and high NO(x)-removal efficiency can be simultaneously achieved with this system but miniaturization of the adsorption chambers will be a challenge. PMID:22771347

  12. Parameterization of plume chemistry into large-scale atmospheric models: Application to aircraft NOx emissions

    NASA Astrophysics Data System (ADS)

    Cariolle, D.; Caro, D.; Paoli, R.; Hauglustaine, D. A.; CuéNot, B.; Cozic, A.; Paugam, R.

    2009-10-01

    A method is presented to parameterize the impact of the nonlinear chemical reactions occurring in the plume generated by concentrated NOx sources into large-scale models. The resulting plume parameterization is implemented into global models and used to evaluate the impact of aircraft emissions on the atmospheric chemistry. Compared to previous approaches that rely on corrected emissions or corrective factors to account for the nonlinear chemical effects, the present parameterization is based on the representation of the plume effects via a fuel tracer and a characteristic lifetime during which the nonlinear interactions between species are important and operate via rates of conversion for the NOx species and an effective reaction rates for O3. The implementation of this parameterization insures mass conservation and allows the transport of emissions at high concentrations in plume form by the model dynamics. Results from the model simulations of the impact on atmospheric ozone of aircraft NOx emissions are in rather good agreement with previous work. It is found that ozone production is decreased by 10 to 25% in the Northern Hemisphere with the largest effects in the north Atlantic flight corridor when the plume effects on the global-scale chemistry are taken into account. These figures are consistent with evaluations made with corrected emissions, but regional differences are noticeable owing to the possibility offered by this parameterization to transport emitted species in plume form prior to their dilution at large scale. This method could be further improved to make the parameters used by the parameterization function of the local temperature, humidity and turbulence properties diagnosed by the large-scale model. Further extensions of the method can also be considered to account for multistep dilution regimes during the plume dissipation. Furthermore, the present parameterization can be adapted to other types of point-source NOx emissions that have to be

  13. Influences of O{sub 2} concentration on NO reduction and N{sub 2}O formation in thermal deNOx process

    SciTech Connect

    Zhi-Min, L.; Ji-Dong, L.

    2009-06-15

    Flow reactor experiment and chemical kinetic modeling were carried out to evaluate the influences of oxygen concentration on NO reduction and N{sub 2}O formation during thermal deNOx process for temperatures of 1073-1473 K. Increasing oxygen concentration in the reactant gas from 0.3 to 9.3% not only reduces the NO reduction potential and N{sub 2}O emission, but also lowers and widens the 'temperature window' for NO conversion and N{sub 2}O formation. Trace amount of impurity O{sub 2} leads to the lowest NO emission at a high temperature of 1373 K with low N{sub 2}O emission. Test reveals that high molar ratio NH{sub 3}/NO suppresses the reverse effect of oxygen and brings out high percentage of NO reduction at leaner environment. Chemical kinetic simulations using 4 detailed mechanisms display differing trends in the NO and N{sub 2}O dependence on O{sub 2} and temperature. Rota 2000 model gives the best description of our experiments, but some assumptions made in this mechanism are not fully realistic. This study provides new experimental data on the less noticed N{sub 2}O, and raises a question about the understanding of the detailed elementary chemistry on the thermal deNOx process. Further work is still required for reasonable kinetic explanations.

  14. Excellent activity and selectivity of Cu-SSZ-13 in the selective catalytic reduction of NOx with NH3

    SciTech Connect

    Kwak, Ja Hun; Tonkyn, Russell G.; Kim, Do Heui; Szanyi, Janos; Peden, Charles HF

    2010-10-21

    Superior activity and selectivity of a Cu ion-exchanged SSZ-13 zeolite in the selective catalytic reduction (SCR) of NOx with NH3 were observed, in comparison to Cu-beta and Cu-ZSM-5 zeolites. Cu-SSZ-13 was not only more active in the NOx SCR reaction over the entire temperature range studied (up to 550 °C), but also more selective toward nitrogen formation, resulting in significantly lower amounts of NOx by-products (i.e., NO2 and N2O) than the other two zeolites. In addition, Cu-SSZ-13 demonstrated the highest activity and N2 formation selectivity in the oxidation of NH3. The results of this study strongly suggest that Cu-SSZ-13 is a promising candidate as a catalyst for NOx SCR with great potential in after-treatment systems for either mobile or stationary sources.

  15. Role of reductants in CuZSM-5 catalyzed NOx reduction

    SciTech Connect

    Bhore, N.A.; Dwyer, F.G.; Marler, D.O.; McWilliams, J.P.

    1993-12-31

    The implementation of clean burn engines is limited by technology to efficiently remove nitrogen oxides from the net oxidizing exhaust composition. High NO{sub x} conversions require the preferential reaction of reductants (hydrogen, carbon monoxide, olefins and paraffins) with nitrogen oxides over that of combustion. This study examines the role of these reactions over CuZM-5 catalyst in a simulated lean burn engine exhaust. By careful addition of a known amount of individual reductant over fresh and aged catalysts, the authors find that propylene is the primary-reductant for NO{sub x} conversion; hydrogen and carbon monoxide are not. For stoichiometric-burn engines, carbon monoxide and hydrogen are known to be primary reductants on three-way catalysts. Other light olefins such as isobutylene and ethylene are also effective in NO{sub x} reduction. Paraffins are much less effective. The efficacy of olefin reductant decreases on aging.

  16. UTILIZING WATER EMULSIFICATION TO REDUCE NOX AND PARTICULATE EMISSIONS ASSOCIATED WITH BIODIESEL

    SciTech Connect

    Kass, Michael D; Lewis Sr, Samuel Arthur; Lee, Doh-Won; Huff, Shean P; Storey, John Morse; Swartz, Matthew M; Wagner, Robert M

    2009-01-01

    A key barrier limiting extended utilization of biodiesel is higher NOx emissions compared to petrodiesel fuels. The reason for this effect is unclear, but various researchers have attributed this phenomena to the higher liquid bulk modulus associated with biodiesel and the additional heat released during the breaking of C-C double bonds in the methyl ester groups. In this study water was incorporated into neat biodiesel (B100) as an emulsion in an attempt to lower NOx and particulate matter (PM) emissions. A biodiesel emulsion containing 10wt% water was formulated and evaluated against an ultra-low sulfur petroleum diesel (ULSD) and neat biodiesel (B100) in a light-duty diesel engine operated at 1500RPM and at loads of 68Nm (50ft-lbs) and 102Nm (75ft-lbs). The influence of exhaust gas recirculation (EGR) was also examined. The incorporation of water was found to significantly lower the NOx emissions of B100, while maintaining fuel efficiency when operating at 0 and 27% EGR. The soot fraction of the particulates (as determined using an opacity meter) was much lower for the B100 and B100-water emulsion compared ULSD. In contrast, total PM mass (for the three fuel types) was unchanged for the 0% EGR condition but was significantly lower for the B100 and B100-emulsion during the 27% EGR condition compared to the ULSD fuel. Analysis of the emissions and heat release data indicate that water enhances air-fuel premixing to maintain fuel economy and lower soot formation. The exhaust chemistry of the biodiesel base fuels (B100 and water-emulsified B100) was found to be unique in that they contained measurable levels of methyl alkenoates, which were not found for the ULSD. These compounds were formed by the partial cracking of the methyl ester groups during combustion.

  17. Adaptive engine injection for emissions reduction

    DOEpatents

    Reitz, Rolf D. : Sun, Yong

    2008-12-16

    NOx and soot emissions from internal combustion engines, and in particular compression ignition (diesel) engines, are reduced by varying fuel injection timing, fuel injection pressure, and injected fuel volume between low and greater engine loads. At low loads, fuel is injected during one or more low-pressure injections occurring at low injection pressures between the start of the intake stroke and approximately 40 degrees before top dead center during the compression stroke. At higher loads, similar injections are used early in each combustion cycle, in addition to later injections which preferably occur between about 90 degrees before top dead center during the compression stroke, and about 90 degrees after top dead center during the expansion stroke (and which most preferably begin at or closely adjacent the end of the compression stroke). These later injections have higher injection pressure, and also lower injected fuel volume, than the earlier injections.

  18. Reduction of NOx and PM in marine diesel engine exhaust gas using microwave plasma

    NASA Astrophysics Data System (ADS)

    Balachandran, W.; FInst, P.; Manivannan, N.; Beleca, R.; Abbod, M.

    2015-10-01

    Abatement of NOx and particulate matters (PM) of marine diesel exhaust gas using microwave (MW) non-thermal plasma is presented in this paper. NOx mainly consist of NO and less concentration of NO2 in a typical two stoke marine diesel engine and microwave plasma generation can completely remove NO. MW was generated using two 2kW microwave sources and a saw tooth passive electrode. Passive electrode was used to generate high electric field region within microwave environment where high energetic electrons (1-3eV) are produced for the generation of non-thermal plasma (NTP). 2kW gen-set diesel exhaust gas was used to test our pilot-scale MW plasma reactor. The experimental results show that almost 100% removal of NO is possible for the exhaust gas flow rate of 60l/s. It was also shown that MW can significantly remove soot particles (PM, 10nm to 365nm) entrained in the exhaust gas of 200kW marine diesel engine with 40% engine load and gas flow rate of 130l/s. MW without generating plasma showed reduction up to 50% reduction of PM and with the plasma up to 90% reduction. The major challenge in these experiments was that igniting the desired plasma and sustaining it with passive electrodes for longer period (10s of minutes) as it required fine tuning of electrode position, which was influenced by many factors such as gas flow rate, geometry of reactor and MW power.

  19. SNCR De-NOx within a moderate temperature range using urea-spiked hydrazine hydrate as reductant.

    PubMed

    Chen, H; Chen, D Z; Fan, S; Hong, L; Wang, D

    2016-10-01

    In this research, urea-spiked hydrazine hydrate solutions are used as reductants for the Selective Non-Catalytic Reduction (SNCR) De-NOx process below 650 °C. The urea concentration in the urea/hydrazine hydrate solutions is chosen through experimental and theoretical studies. To determine the mechanism of the De-NOx process, thermogravimetric analysis (TGA) of the urea/hydrazine hydrate solutions and their thermal decomposition in air and nitrogen atmospheres were studied to understand their decomposition behaviours and redox characteristics. Then a plug flow reactor (PFR) model was adopted to simulate the De-NOx processes in a pilot scale tubular reactor, and the calculated De-NOx efficiency vs. temperature profiles were compared with experimental results to support the mechanism and choose the proper reductant and its reaction temperature. Both the experimental and calculated results show that when the urea is spiked into hydrazine hydrate solution to make the urea-N content approximately 16.7%-25% of the total N content in the solution, better De-NOx efficiencies can be obtained in the temperature range of 550-650 °C, under which NH3 is inactive in reducing NOx. And it is also proved that for these urea-spiked hydrazine hydrate solutions, the hydrazine decomposition through the pathway N2H4 + M = N2H3 + H + M is enhanced to provide radical H, which is active to reduce NO. Finally, the reaction routes for SNCR De-NOx process based on urea-spiked hydrazine hydrate at the proper temperature are proposed.

  20. SNCR De-NOx within a moderate temperature range using urea-spiked hydrazine hydrate as reductant.

    PubMed

    Chen, H; Chen, D Z; Fan, S; Hong, L; Wang, D

    2016-10-01

    In this research, urea-spiked hydrazine hydrate solutions are used as reductants for the Selective Non-Catalytic Reduction (SNCR) De-NOx process below 650 °C. The urea concentration in the urea/hydrazine hydrate solutions is chosen through experimental and theoretical studies. To determine the mechanism of the De-NOx process, thermogravimetric analysis (TGA) of the urea/hydrazine hydrate solutions and their thermal decomposition in air and nitrogen atmospheres were studied to understand their decomposition behaviours and redox characteristics. Then a plug flow reactor (PFR) model was adopted to simulate the De-NOx processes in a pilot scale tubular reactor, and the calculated De-NOx efficiency vs. temperature profiles were compared with experimental results to support the mechanism and choose the proper reductant and its reaction temperature. Both the experimental and calculated results show that when the urea is spiked into hydrazine hydrate solution to make the urea-N content approximately 16.7%-25% of the total N content in the solution, better De-NOx efficiencies can be obtained in the temperature range of 550-650 °C, under which NH3 is inactive in reducing NOx. And it is also proved that for these urea-spiked hydrazine hydrate solutions, the hydrazine decomposition through the pathway N2H4 + M = N2H3 + H + M is enhanced to provide radical H, which is active to reduce NO. Finally, the reaction routes for SNCR De-NOx process based on urea-spiked hydrazine hydrate at the proper temperature are proposed. PMID:27427778

  1. TCM aircraft piston engine emission reduction program

    NASA Technical Reports Server (NTRS)

    Rezy, B. J.

    1976-01-01

    The technology necessary to safely reduce general aviation piston engine exhaust emissions to meet the EPA 1980 Emission Standards with minimum adverse effects on cost, weight, fuel economy, and performance was demonstrated. A screening and assessment of promising emission reduction concepts was provided, and the preliminary design and development of those concepts was established. A system analysis study and a decision making procedure were used by TCM to evaluate, trade off, and rank the candidate concepts from a list of 14 alternatives. Cost, emissions, and 13 other design criteria considerations were defined and traded off against each candidate concept to establish its merit and emission reduction usefulness. A computer program was used to aid the evaluators in making the final choice of three concepts.

  2. Analysis of UK and European NOx and VOC emission scenarios in the Defra model intercomparison exercise

    NASA Astrophysics Data System (ADS)

    Derwent, Richard; Beevers, Sean; Chemel, Charles; Cooke, Sally; Francis, Xavier; Fraser, Andrea; Heal, Mathew R.; Kitwiroon, Nutthida; Lingard, Justin; Redington, Alison; Sokhi, Ranjeet; Vieno, Massimo

    2014-09-01

    Simple emission scenarios have been implemented in eight United Kingdom air quality models with the aim of assessing how these models compared when addressing whether photochemical ozone formation in southern England was NOx- or VOC-sensitive and whether ozone precursor sources in the UK or in the Rest of Europe (RoE) were the most important during July 2006. The suite of models included three Eulerian-grid models (three implementations of one of these models), a Lagrangian atmospheric dispersion model and two moving box air parcel models. The assignments as to NOx- or VOC-sensitive and to UK- versus RoE-dominant, turned out to be highly variable and often contradictory between the individual models. However, when the assignments were filtered by model performance on each day, many of the contradictions could be eliminated. Nevertheless, no one model was found to be the 'best' model on all days, indicating that no single air quality model could currently be relied upon to inform policymakers robustly in terms of NOx- versus VOC-sensitivity and UK- versus RoE-dominance on each day. It is important to maintain a diversity in model approaches.

  3. Closed loop engine control for regulating NOx emissions, using a two-dimensional fuel-air curve

    DOEpatents

    Bourn, Gary D.; Smith, Jack A.; Gingrich, Jess W.

    2007-01-30

    An engine control strategy that ensures that NOx emissions from the engine will be maintained at an acceptable level. The control strategy is based on a two-dimensional fuel-air curve, in which air manifold pressure (AMP) is a function of fuel header pressure and engine speed. The control strategy provides for closed loop NOx adjustment to a base AMP value derived from the fuel-air curve.

  4. 40 CFR Appendix E to Part 75 - Optional NOX Emissions Estimation Protocol for Gas-Fired Peaking Units and Oil-Fired Peaking Units

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ....1Initial Performance Testing Use the following procedures for: measuring NOX emission rates at heat input rate levels corresponding to different load levels; measuring heat input rate; and plotting the correlation between heat input rate and NOX emission rate, in order to determine the emission rate of the...

  5. Damages and Expected Deaths Due to Excess NOx Emissions from 2009 to 2015 Volkswagen Diesel Vehicles.

    PubMed

    Holland, Stephen P; Mansur, Erin T; Muller, Nicholas Z; Yates, Andrew J

    2016-02-01

    We estimate the damages and expected deaths in the United States due to excess emissions of NOx from 2009 to 2015 Volkswagen diesel vehicles. Using data on vehicle registrations and a model of pollution transport and valuation, we estimate excess damages of $430 million and 46 excess expected deaths. Accounting for uncertainty about emissions gives a range for damages from $350 million to $500 million, and a range for excess expected deaths from 40 to 52. Our estimates incorporate significant local heterogeneity: for example, Minneapolis has the highest damages despite having fewer noncompliant vehicles than 13 other cities. Our estimated damages greatly exceed possible benefits from reduced CO2 emissions due to increased fuel economy. PMID:26720281

  6. Damages and Expected Deaths Due to Excess NOx Emissions from 2009 to 2015 Volkswagen Diesel Vehicles.

    PubMed

    Holland, Stephen P; Mansur, Erin T; Muller, Nicholas Z; Yates, Andrew J

    2016-02-01

    We estimate the damages and expected deaths in the United States due to excess emissions of NOx from 2009 to 2015 Volkswagen diesel vehicles. Using data on vehicle registrations and a model of pollution transport and valuation, we estimate excess damages of $430 million and 46 excess expected deaths. Accounting for uncertainty about emissions gives a range for damages from $350 million to $500 million, and a range for excess expected deaths from 40 to 52. Our estimates incorporate significant local heterogeneity: for example, Minneapolis has the highest damages despite having fewer noncompliant vehicles than 13 other cities. Our estimated damages greatly exceed possible benefits from reduced CO2 emissions due to increased fuel economy.

  7. Experiment and mechanism investigation on advanced reburning for NOx reduction: influence of CO and temperature

    PubMed Central

    Wang, Zhi-hua; Zhou, Jun-hu; Zhang, Yan-wei; Lu, Zhi-min; Fan, Jian-ren; Cen, Ke-fa

    2005-01-01

    Pulverized coal reburning, ammonia injection and advanced reburning in a pilot scale drop tube furnace were investigated. Premix of petroleum gas, air and NH3 were burned in a porous gas burner to generate the needed flue gas. Four kinds of pulverized coal were fed as reburning fuel at constant rate of 1g/min. The coal reburning process parameters including 15%~25% reburn heat input, temperature range from 1100 °C to 1400 °C and also the carbon in fly ash, coal fineness, reburn zone stoichiometric ratio, etc. were investigated. On the condition of 25% reburn heat input, maximum of 47% NO reduction with Yanzhou coal was obtained by pure coal reburning. Optimal temperature for reburning is about 1300 °C and fuel-rich stoichiometric ratio is essential; coal fineness can slightly enhance the reburning ability. The temperature window for ammonia injection is about 700 °C~1100 °C. CO can improve the NH3 ability at lower temperature. During advanced reburning, 72.9% NO reduction was measured. To achieve more than 70% NO reduction, Selective Non-catalytic NOx Reduction (SNCR) should need NH3/NO stoichiometric ratio larger than 5, while advanced reburning only uses common dose of ammonia as in conventional SNCR technology. Mechanism study shows the oxidization of CO can improve the decomposition of H2O, which will rich the radical pools igniting the whole reactions at lower temperatures. PMID:15682503

  8. Mixing and NOx Emission Calculations of Confined Reacting Jet Flows in Cylindrical and Annular Ducts

    NASA Technical Reports Server (NTRS)

    Oechsle, Victor L.; Connor, Christopher H.; Holdeman, James D. (Technical Monitor)

    2000-01-01

    Rapid mixing of cold lateral jets with hot cross-stream flows in confined configurations is of practical interest in gas turbine combustors as it strongly affects combustor exit temperature quality, and gaseous emissions in for example rich-lean combustion. It is therefore important to further improve our fundamental understanding of the important processes of dilution jet mixing especially when the injected jet mass flow rate exceeds that of the cross-stream. The results reported in this report describe some of the main flow characteristics which develop in the mixing process in a cylindrical duct. A three-dimensional computational fluid dynamics (CFD) code has been used to predict the mixing flow field characteristics and NOx emission in a quench section of a rich-burn/quick-mix/lean-burn (RQL) combustor. Sixty configurations have been analyzed in both circular and annular geometries in a fully reacting environment simulating the operating condition of an actual RQL gas turbine combustion liner. The evaluation matrix was constructed by varying the number of orifices per row and orifice shape. Other parameters such as J (momentum-flux ratio), MR (mass flowrate ratio), DR (density ratio), and mixer sector orifice ACd (effective orifice area) were maintained constant throughout the entire study. The results indicate that the mixing flow field can be correlated with the NOx production if they are referenced with the stoichiometric equivalence ratio value and not the equilibrium value. The mixing flowfields in both circular and annular mixers are different. The penetration of equal jets in both annular and circular geometries is vastly different which significantly affects the performance of the mixing section. In the computational results with the circular mixer, most of the NOx formation occurred behind the orifice starting at the orifice wake region. General trends have been observed in the NOx production as the number of orifices is changed and this appears to be

  9. Estimations of primary nitrogen dioxide exhaust emissions from chemiluminescence NOx measurements in a UK road tunnel.

    PubMed

    Simmons, W A; Seakins, P W

    2012-11-01

    NO and NO(2) measurements have been made using the chemiluminescence method from 115 weekdays during the period 4th Jan-10th Sep 2010 in a well characterised, unventilated tunnel on the Leeds Inner Ring Road. Measurements are made at two points in the tunnel and the difference in NO and NO(2) was attributed to emissions from vehicles in the tunnel. These data have been used to determine the fraction of NOx (NO+NO(2)) as primary NO(2) (f-NO(2)) from vehicles using the tunnel. The average value of f-NO(2) from 7 am to 7 pm was 0.17 (-0.03)(+0.01) in agreement with estimations from the UK National Atmospheric Emissions Inventory (NAEI). However, during the day there was a reproducible increase in f-NO(2) from approximately 0.10 at 7 am to 0.21 at 7 pm which is not reproduced with the current UK vehicle fleet emissions inventories. The increase in f-NO(2) can be qualitatively linked to a decrease in the fraction of NOx arising from heavy goods vehicles and buses. PMID:23000714

  10. Using satellite observations to quantify biomass burning emissions of NOx, and hydrocarbons in the Tropics

    NASA Technical Reports Server (NTRS)

    Jaegle, Lyatt

    2005-01-01

    This is the final report for "Using satellite observations to quantify biomass burning emissions of NOx and hydrocarbons in the Tropics", funded through the New Investigator Program between March 2001 and March 2005. This period includes a 1-year no-cost extension of the original award. This report summarizes our accomplishments during the duration of the grant. Section 2 focuses on the research component of this work, while section 3 describes the education component. The personnel supported under this project is given in section 4. Section 5 lists publications resulting from NASA support and section 6 provides a list of conferences and seminars where the results were presented.

  11. Anthropogenic emissions of NOx over China: Reconciling the difference of inverse modeling results using GOME-2 and OMI measurements

    SciTech Connect

    Gu, Dasa; Wang, Yuhang; Smeltzer, Charles; Boersma, K. Folkert

    2014-06-27

    Inverse modeling using satellite observations of nitrogen dioxide (NO2) columns has been extensively used to estimate nitrogen oxides (NOx) emissions in China. Recently, the Global Ozone Monitoring Experiment-2 (GOME-2) and Ozone Monitoring Instrument (OMI) provide independent global NO2 column measurements on a nearly daily basis at around 9:30 and 13:30 local time across the equator, respectively. Anthropogenic NOx emission estimates by applying previously developed monthly inversion (MI) or daily inversion (DI) methods to these two sets of measurements show substantial differences. We improve the DI method by conducting model simulation, satellite retrieval, and inverse modeling sequentially on a daily basis. After each inversion, we update anthropogenic NOx emissions in the model simulation with the newly obtained a posteriori results. Consequently, the inversion-optimized emissions are used to compute the a priori NO2 profiles for satellite retrievals. As such, the a priori profiles used in satellite retrievals are now coupled to inverse modeling results. The improved procedure was applied to GOME-2 and OMI NO2 measurements in 2011. The new daily retrieval-inversion (DRI) method estimates an average NOx emission of 6.9 Tg N/yr over China, and the difference between using GOME-2 and OMI measurements is 0.4 Tg N/yr, which is significantly smaller than the difference of 1.3 Tg N/yr using the previous DI method. Using the more consistent DRI inversion results, we find that anthropogenic NOx emissions tend to be higher in winter and summer than spring (and possibly fall) and the weekday-to-weekend emission ratio tends to increase with NOx emission in China.

  12. Analysis of Strategies for Multiple Emissions from Electric Power SO2, NOX, CO2, Mercury and RPS

    EIA Publications

    2001-01-01

    At the request of the Subcommittee, the Energy Information Administration prepared an initial report that focused on the impacts of reducing power sector NOx, SO2, and CO2 emissions. The current report extends the earlier analysis to add the impacts of reducing power sector mercury emissions and introducing renewable portfolio standard (RPS) requirements.

  13. Exhaust particle and NOx emission performance of an SCR heavy duty truck operating in real-world conditions

    NASA Astrophysics Data System (ADS)

    Saari, Sampo; Karjalainen, Panu; Ntziachristos, Leonidas; Pirjola, Liisa; Matilainen, Pekka; Keskinen, Jorma; Rönkkö, Topi

    2016-02-01

    Particle and NOx emissions of an SCR equipped HDD truck were studied in real-world driving conditions using the "Sniffer" mobile laboratory. Real-time CO2 measurement enables emission factor calculation for NOx and particles. In this study, we compared three different emission factor calculation methods and characterised their suitability for real-world chasing experiments. The particle number emission was bimodal and dominated by the nucleation mode particles (diameter below 23 nm) having emission factor up to 1 × 1015 #/kgfuel whereas emission factor for soot (diameter above 23 nm that is consistent with the PMP standard) was typically 1 × 1014 #/kgfuel. The effect of thermodenuder on the exhaust particles indicated that the nucleation particles consisted mainly of volatile compounds, but sometimes there also existed a non-volatile core. The nucleation mode particles are not controlled by current regulations in Europe. However, these particles consistently form under atmospheric dilution in the plume of the truck and constitute a health risk for the human population that is exposed to those. Average NOx emission was 3.55 g/kWh during the test, whereas the Euro IV emission limit over transient testing is 3.5 g NOx/kWh. The on-road emission performance of the vehicle was very close to the expected levels, confirming the successful operation of the SCR system of the tested vehicle. Heavy driving conditions such as uphill driving increased both the NOx and particle number emission factors whereas the emission factor for soot particle number remains rather constant.

  14. Locomotive Emission and Engine Idle Reduction Technology Demonstration Project

    SciTech Connect

    John R. Archer

    2005-03-14

    In response to a United States Department of Energy (DOE) solicitation, the Maryland Energy Administration (MEA), in partnership with CSX Transportation, Inc. (CSXT), submitted a proposal to DOE to support the demonstration of Auxiliary Power Unit (APU) technology on fifty-six CSXT locomotives. The project purpose was to demonstrate the idle fuel savings, the Nitrous Oxide (NOX) emissions reduction and the noise reduction capabilities of the APU. Fifty-six CSXT Baltimore Division locomotives were equipped with APUs, Engine Run Managers (ERM) and communications equipment to permit GPS tracking and data collection from the locomotives. Throughout the report there is mention of the percent time spent in the State of Maryland. The fifty-six locomotives spent most of their time inside the borders of Maryland and some spent all their time inside the state borders. Usually when a locomotive traveled beyond the Maryland State border it was into an adjoining state. They were divided into four groups according to assignment: (1) Power Unit/Switcher Mate units, (2) Remote Control units, (3) SD50 Pusher units and (4) Other units. The primary data of interest were idle data plus the status of the locomotive--stationary or moving. Also collected were main engine off, idling or working. Idle data were collected by county location, by locomotive status (stationary or moving) and type of idle (Idle 1, main engine idling, APU off; Idle 2, main engine off, APU on; Idle 3, main engine off, APU off; Idle 4, main engine idle, APU on). Desirable main engine idle states are main engine off and APU off or main engine off and APU on. Measuring the time the main engine spends in these desirable states versus the total time it could spend in an engine idling state allows the calculation of Percent Idle Management Effectiveness (%IME). IME is the result of the operation of the APU plus the implementation of CSXT's Warm Weather Shutdown Policy. It is difficult to separate the two. The units

  15. Photochemical modeling in California with two chemical mechanisms: model intercomparison and response to emission reductions.

    PubMed

    Cai, Chenxia; Kelly, James T; Avise, Jeremy C; Kaduwela, Ajith P; Stockwell, William R

    2011-05-01

    An updated version of the Statewide Air Pollution Research Center (SAPRC) chemical mechanism (SAPRC07C) was implemented into the Community Multiscale Air Quality (CMAQ) version 4.6. CMAQ simulations using SAPRC07C and the previously released version, SAPRC99, were performed and compared for an episode during July-August, 2000. Ozone (O3) predictions of the SAPRC07C simulation are generally lower than those of the SAPRC99 simulation in the key areas of central and southern California, especially in areas where modeled concentrations are greater than the federal 8-hr O3 standard of 75 parts per billion (ppb) and/or when the volatile organic compound (VOC)/nitrogen oxides (NOx) ratio is less than 13. The relative changes of ozone production efficiency (OPE) against the VOC/NOx ratio at 46 sites indicate that the OPE is reduced in SAPRC07C compared with SAPRC99 at most sites by as much as approximately 22%. The SAPRC99 and SAPRC07C mechanisms respond similarly to 20% reductions in anthropogenic VOC emissions. The response of the mechanisms to 20% NOx emissions reductions can be grouped into three cases. In case 1, in which both mechanisms show a decrease in daily maximum 8-hr O3 concentration with decreasing NOx emissions, the O3 decrease in SAPRC07C is smaller. In case 2, in which both mechanisms show an increase in O3 with decreasing NOx emissions, the O3 increase is larger in SAPRC07C. In case 3, SAPRC07C simulates an increase in O3 in response to reduced NOx emissions whereas SAPRC99 simulates a decrease in O3 for the same region. As a result, the areas where NOx controls would be disbeneficial are spatially expanded in SAPRC07C. Although the results presented here are valuable for understanding differences in predictions and model response for SAPRC99 and SAPRC07C, the study did not evaluate the impact of mechanism differences in the context of the U.S. Environmental Protection Agency's guidance for using numerical models in demonstrating air quality attainment

  16. Photochemical modeling in California with two chemical mechanisms: model intercomparison and response to emission reductions.

    PubMed

    Cai, Chenxia; Kelly, James T; Avise, Jeremy C; Kaduwela, Ajith P; Stockwell, William R

    2011-05-01

    An updated version of the Statewide Air Pollution Research Center (SAPRC) chemical mechanism (SAPRC07C) was implemented into the Community Multiscale Air Quality (CMAQ) version 4.6. CMAQ simulations using SAPRC07C and the previously released version, SAPRC99, were performed and compared for an episode during July-August, 2000. Ozone (O3) predictions of the SAPRC07C simulation are generally lower than those of the SAPRC99 simulation in the key areas of central and southern California, especially in areas where modeled concentrations are greater than the federal 8-hr O3 standard of 75 parts per billion (ppb) and/or when the volatile organic compound (VOC)/nitrogen oxides (NOx) ratio is less than 13. The relative changes of ozone production efficiency (OPE) against the VOC/NOx ratio at 46 sites indicate that the OPE is reduced in SAPRC07C compared with SAPRC99 at most sites by as much as approximately 22%. The SAPRC99 and SAPRC07C mechanisms respond similarly to 20% reductions in anthropogenic VOC emissions. The response of the mechanisms to 20% NOx emissions reductions can be grouped into three cases. In case 1, in which both mechanisms show a decrease in daily maximum 8-hr O3 concentration with decreasing NOx emissions, the O3 decrease in SAPRC07C is smaller. In case 2, in which both mechanisms show an increase in O3 with decreasing NOx emissions, the O3 increase is larger in SAPRC07C. In case 3, SAPRC07C simulates an increase in O3 in response to reduced NOx emissions whereas SAPRC99 simulates a decrease in O3 for the same region. As a result, the areas where NOx controls would be disbeneficial are spatially expanded in SAPRC07C. Although the results presented here are valuable for understanding differences in predictions and model response for SAPRC99 and SAPRC07C, the study did not evaluate the impact of mechanism differences in the context of the U.S. Environmental Protection Agency's guidance for using numerical models in demonstrating air quality attainment

  17. Elucidating N2O Formation during the Cyclic NOx Storage and Reduction Process Using CO as a Reductant.

    PubMed

    Wang, Jun; Wang, Xiuting; Zhu, Jinxin; Wang, Jianqiang; Shen, Meiqing

    2015-07-01

    The N2O formation pathway and effect of H2O on N2O formation during the NOx storage and reduction (NSR) process using CO as a reductant were investigated over a Pt-BaO/Al2O3 catalyst. The NSR activity measurements and transient in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) experiments were performed to evaluate N2O evolution and elucidate the N2O formation mechanism. N2O is formed in the lean, rich, and delay2 phases. In the lean phase, N2O formation is related to the reactions between surface isocyanate and gaseous NO/O2 and NO is more responsible for N2O formation than O2. Moreover, N2O production decreases with H2O because of the hydrolysis of isocyanate species. In the rich phase, the amount of N2O formation also decreases in the presence of H2O at a higher temperature because of the high reduction ability of H2 generated from the water-gas shift (WGS) reaction. During the delay2 phase, N2O is mainly formed by nitrite species reacting with Pt(0)-CO. Furthermore, the presence of H2O decreases the stability of nitrites and results in more N2O production at a low temperature.

  18. Towards a targetted emission reduction in Europe

    NASA Astrophysics Data System (ADS)

    Hordijk, Leen

    Currently 20 European countries have stated that they will reduce their SO 2-emissions by at least 30% in the years 1993-1995 based on 1980 emissions. Some countries will reduce more, e.g. France by 50 %. Although politically this is an important step, a more or less flat rate of emission reduction throughout Europe is not an efficient solution. The paper describes an alternate emission reduction targetted to those areas where depositions are high and taking into account the source-receptor relationships in Europe. The reductions are calculated by using the model RAINS which is being developed at IIASA. RAINS is a set of linked submodels dealing with energy scenarios, SO 2 emissions, abatement options, long-range transport, deposition, forest soil acidification and lake acidification. For the purpose of this paper an optimization algorithm developed by R. Shaw and J. Young (AES, Canada) has been connected with RAINS. The results show optimal reduction patterns in Europe for a number of different receptor areas and alternative energy scenarios.

  19. Evaluation of microbial reduction of Fe(III)EDTA in a chemical absorption-biological reduction integrated NOx removal system

    SciTech Connect

    Wei Li; Cheng-Zhi Wu; Shi-Han Zhang; Ke Shao; Yao Shi

    2007-01-15

    A chemical absorption-biological reduction integrated process can be used to remove nitrogen oxides (NOx) from flue gas. In such a process, nitric oxide (NO) can be effectively absorbed by the ferrous chelate of ethylenediaminetetraacetate (Fe(II)EDTA) to form Fe(II)EDTA-NO, which can be biologically regenerated by denitrifying bacteria. However, in the course of these processes, part of the Fe(II)EDTA is also oxidized to Fe(III)EDTA. The reduction of Fe(III)EDTA to Fe(II)EDTA depends on the activity of iron-reducing bacteria in the system. Therefore, the effectiveness of the system relies on how to effectively bioreduce Fe(III)EDTA and Fe(II)EDTA-NO in the system. In this paper, a strain identified as Escherichia coli FR-2 (iron-reducing bacterium) was used to investigate the reduction rate of Fe(III)EDTA. The experimental results indicate that Fe(II)EDTA-NO and Fe(II)EDTA in the system can inhibit both the FR-2 cell growth and thus affect the Fe(III)EDTA reduction. The FR-2 cell growth rate and Fe(III)EDTA reduction rate decreased with increasing Fe(II)EDTA-NO and Fe(II)EDTA concentration in the solution. When the concentration of Fe(II)EDTA-NO reached 3.7 mM, the FR-2 cell growth almost stopped. A mathematical model was developed to explain the cell growth and inhibition kinetics. The predicted results are close to the experimental data and provide a preliminary evaluation of the kinetics of the biologically mediated reactions necessary to regenerate the spent scrubber solution. 33 refs., 7 figs., 2 tabs.

  20. Reduction of solvent emissions from vapor degreasing

    SciTech Connect

    Buresh, P.

    1989-12-31

    Hutchinson Tehnology, Inc. (HTI) implemented a number of low cost, low technology procedures to reduce emissions and prevent solvent loss from two open-top freon (CFC-113) vapor degreasers (Branson No. 1 and No. 2). HTI is a computer components manufacturer that uses freon vapor degreasing systems to remove fluxes and other residues remaining on the flexible printed circuits from the soldering process. With relatively minor changes in operation, solvent emissions were reduced by an average of 2.8 gallons per day (GDP) for both degreasers combined. It is anticipated that HTI will follow through with installation of an automatic cover, which can result in further solvent emissions reduction.

  1. Control of diesel soot and NOx emissions with a particulate trap and EGR.

    PubMed

    Liu, Rui-xiang; Gao, Xi-yan; Yang, De-sheng; Xu, Xiao-guang

    2005-01-01

    The exhaust gas recirculation (EGR), coupled with a high-collection efficiency particulate trap to simultaneously control smoke and NOx emissions from diesel engines were studied. This ceramic trap developed previously provided the soot cleaning efficiency of 99%, the regeneration efficiency reaches 80% and the ratio of success reaches 97%, which make EGR used in diesel possible. At the presence of EGR, opening of the regeneration control valve of the trap was over again optimized to compensate for the decrease of the oxygen concentration in the exhaust gas resulted from EGR. The results indicated the cleaning efficiency and regeneration performance of the trap were maintained at the same level except that the back pressure increased faster. A new EGR system was developed, which is based on a wide range oxygen (UEGO) sensor. Experiments were carried out under steady state conditions while maintaining the engine speed at 1600 r/min, setting the engine loads at 0%, 25%, 50%, 75% and 100% respectively. Throughout each test the EGR rate was kept at nine different settings and data were taken with the gas analyzer and UEGO sensor. Then, the EGR rate and engine load maps, which showed the tendencies of NOx, CO and HC emissions from diesel engine, were made using the measured data. Using the maps, the author set up the EGR regulation, the relationship between the optimal amounts of EGR flow and the equivalence ratio, sigma, where sigma = 14.5/AFR.

  2. Exhaust emissions reduction from diesel engine using combined Annona-Eucalyptus oil blends and antioxidant additive

    NASA Astrophysics Data System (ADS)

    Senthil, R.; Silambarasan, R.; Pranesh, G.

    2016-07-01

    The limited resources, rising petroleum prices and depletion of fossil fuel have now become a matter of great concern. Hence, there is an urgent need for researchers to find some alternate fuels which are capable of substituting partly or wholly the higher demanded conventional diesel fuel. Lot of research work has been conducted on diesel engine using biodiesel and its blends with diesel as an alternate fuel. Very few works have been done with combination of biodiesel-Eucalypts oil without neat diesel and this leads to lots of scope in this area. The aim of the present study is to analyze the performance and emission characteristics of a single cylinder, direct injection, compression ignition engine using eucalyptus oil-biodiesel as fuel. The presence of eucalyptus oil in the blend reduces the viscosity and improves the volatility of the blends. The methyl ester of Annona oil is blended with eucalypts oil in 10, 20, 30, 40 and 50 %. The performance and emission characteristics are evaluated by operating the engine at different loads. The performance characteristics such as brake thermal efficiency, brake specific fuel consumption and exhaust gas temperature are evaluated. The emission constituents measured are Carbon monoxide (CO), unburned hydrocarbons (HC), Oxides of nitrogen (NOx) and Smoke. It is found that A50-Eu50 (50 Annona + 50 % Eucalyptus oil) blend showed better performance and reduction in exhaust emissions. But, it showed a very marginal increase in NOx emission when compared to that of diesel. Therefore, in order to reduce the NOx emission, antioxidant additive (A-tocopherol acetate) is mixed with Annona-Eucalyptus oil blends in various proportions by which NOx emission is reduced. Hence, A50-Eu50 blend can be used as an alternate fuel for diesel engine without any modifications.

  3. The sensitivities of emissions reductions for the mitigation of UK PM2.5

    NASA Astrophysics Data System (ADS)

    Vieno, M.; Heal, M. R.; Williams, M. L.; Carnell, E. J.; Nemitz, E.; Stedman, J. R.; Reis, S.

    2016-01-01

    The reduction of ambient concentrations of fine particulate matter (PM2.5) is a key objective for air pollution control policies in the UK and elsewhere. Long-term exposure to PM2.5 has been identified as a major contributor to adverse human health effects in epidemiological studies and underpins ambient PM2.5 legislation. As a range of emission sources and atmospheric chemistry transport processes contribute to PM2.5 concentrations, atmospheric chemistry transport models are an essential tool to assess emissions control effectiveness. The EMEP4UK atmospheric chemistry transport model was used to investigate the impact of reductions in UK anthropogenic emissions of primary PM2.5, NH3, NOx, SOx or non-methane VOC on surface concentrations of PM2.5 in the UK for a recent year (2010) and for a future current legislation emission (CLE) scenario (2030). In general, the sensitivity to UK mitigation is rather small. A 30 % reduction in UK emissions of any one of the above components yields (for the 2010 simulation) a maximum reduction in PM2.5 in any given location of ˜ 0.6 µg m-3 (equivalent to ˜ 6 % of the modelled PM2.5). On average across the UK, the sensitivity of PM2.5 concentrations to a 30 % reduction in UK emissions of individual contributing components, for both the 2010 and 2030 CLE baselines, increases in the order NMVOC, NOx, SOx, NH3 and primary PM2.5; however there are strong spatial differences in the PM2.5 sensitivities across the UK. Consequently, the sensitivity of PM2.5 to individual component emissions reductions varies between area and population weighting. Reductions in NH3 have the greatest effect on area-weighted PM2.5. A full UK population weighting places greater emphasis on reductions of primary PM2.5 emissions, which is simulated to be the most effective single-component control on PM2.5 for the 2030 scenario. An important conclusion is that weighting corresponding to the average exposure indicator metric (using data from the 45

  4. Limitations of ozone data assimilation with adjustment of NOx emissions: mixed effects on NO2 forecasts over Beijing and surrounding areas

    NASA Astrophysics Data System (ADS)

    Tang, Xiao; Zhu, Jiang; Wang, ZiFa; Gbaguidi, Alex; Lin, CaiYan; Xin, JinYuan; Song, Tao; Hu, Bo

    2016-05-01

    This study investigates a cross-variable ozone data assimilation (DA) method based on an ensemble Kalman filter (EnKF) that has been used in the companion study to improve ozone forecasts over Beijing and surrounding areas. The main purpose is to delve into the impacts of the cross-variable adjustment of nitrogen oxide (NOx) emissions on the nitrogen dioxide (NO2) forecasts over this region during the 2008 Beijing Olympic Games. A mixed effect on the NO2 forecasts was observed through application of the cross-variable assimilation approach in the real-data assimilation (RDA) experiments. The method improved the NO2 forecasts over almost half of the urban sites with reductions of the root mean square errors (RMSEs) by 15-36 % in contrast to big increases of the RMSEs over other urban stations by 56-239 %. Over the urban stations with negative DA impacts, improvement of the NO2 forecasts (with 7 % reduction of the RMSEs) was noticed at night and in the morning versus significant deterioration during daytime (with 190 % increase of the RMSEs), suggesting that the negative data assimilation impacts mainly occurred during daytime. Ideal-data assimilation (IDA) experiments with a box model and the same cross-variable assimilation method confirmed the mixed effects found in the RDA experiments. In the same way, NOx emission estimation was improved at night and in the morning even under large biases in the prior emission, while it deteriorated during daytime (except for the case of minor errors in the prior emission). The mixed effects observed in the cross-variable data assimilation, i.e., positive data assimilation impacts on NO2 forecasts over some urban sites, negative data assimilation impacts over the other urban sites, and weak data assimilation impacts over suburban sites, highlighted the limitations of the EnKF under strong nonlinear relationships between chemical variables. Under strong nonlinearity between daytime ozone concentrations and NOx emissions

  5. Characteristics of NOx removal combining dielectric barrier discharge plasma with selective catalytic reduction by C2H5OH

    NASA Astrophysics Data System (ADS)

    Wang, Xing-Quan; Chen, Wei; Guo, Qi-Pei; Li, Yi; Lv, Guo-Hua; Sun, Xiu-Ping; Zhang, Xian-Hui; Feng, Ke-Cheng; Yang, Si-Ze

    2009-07-01

    With the assistance of dielectric barrier discharge (DBD) plasma, selective catalytic reduction of NOx by ethanol over Ag/Al2O3 catalysts was studied. Experimental results show that NOx conversion was greatly enhanced due to the presence of DBD plasma at lower temperature. By varying the DBD voltages or power in 13 kHz frequency at different temperatures, NOx conversion was increased to 40.7% from 6.4% at 176 °C, even to 66.8% from 17.3% at 200 °C. NOx conversion could even be improved to 90% at temperature above 255 °C. It was proposed that nonthermal plasma generated by dielectric barrier discharge reactor was very effective for oxidizing NO to NO2 under excess O2 conditions, which possesses high reactivity with C2H5OH to yield CxHyNzO compound. By reacting with CxHyNzO compound and oxygen, NOx is converted to N2 at low temperatures.

  6. Effects of a combined Diesel particle filter-DeNOx system (DPN) on reactive nitrogen compounds emissions: a parameter study.

    PubMed

    Heeb, Norbert V; Haag, Regula; Seiler, Cornelia; Schmid, Peter; Zennegg, Markus; Wichser, Adrian; Ulrich, Andrea; Honegger, Peter; Zeyer, Kerstin; Emmenegger, Lukas; Zimmerli, Yan; Czerwinski, Jan; Kasper, Markus; Mayer, Andreas

    2012-12-18

    The impact of a combined diesel particle filter-deNO(x) system (DPN) on emissions of reactive nitrogen compounds (RNCs) was studied varying the urea feed factor (α), temperature, and residence time, which are key parameters of the deNO(x) process. The DPN consisted of a platinum-coated cordierite filter and a vanadia-based deNO(x) catalyst supporting selective catalytic reduction (SCR) chemistry. Ammonia (NH₃) is produced in situ from thermolysis of urea and hydrolysis of isocyanic acid (HNCO). HNCO and NH₃ are both toxic and highly reactive intermediates. The deNO(x) system was only part-time active in the ISO8178/4 C1cycle. Urea injection was stopped and restarted twice. Mean NO and NO₂ conversion efficiencies were 80%, 95%, 97% and 43%, 87%, 99%, respectively, for α = 0.8, 1.0, and 1.2. HNCO emissions increased from 0.028 g/h engine-out to 0.18, 0.25, and 0.26 g/h at α = 0.8, 1.0, and 1.2, whereas NH₃ emissions increased from <0.045 to 0.12, 1.82, and 12.8 g/h with maxima at highest temperatures and shortest residence times. Most HNCO is released at intermediate residence times (0.2-0.3 s) and temperatures (300-400 °C). Total RNC efficiencies are highest at α = 1.0, when comparable amounts of reduced and oxidized compounds are released. The DPN represents the most advanced system studied so far under the VERT protocol achieving high conversion efficiencies for particles, NO, NO₂, CO, and hydrocarbons. However, we observed a trade-off between deNO(x) efficiency and secondary emissions. Therefore, it is important to adopt such DPN technology to specific application conditions to take advantage of reduced NO(x) and particle emissions while avoiding NH₃ and HNCO slip.

  7. Emission reductions from woody biomass waste for energy as an alternative to open burning.

    PubMed

    Springsteen, Bruce; Christofk, Tom; Eubanks, Steve; Mason, Tad; Clavin, Chris; Storey, Brett

    2011-01-01

    Woody biomass waste is generated throughout California from forest management, hazardous fuel reduction, and agricultural operations. Open pile burning in the vicinity of generation is frequently the only economic disposal option. A framework is developed to quantify air emissions reductions for projects that alternatively utilize biomass waste as fuel for energy production. A demonstration project was conducted involving the grinding and 97-km one-way transport of 6096 bone-dry metric tons (BDT) of mixed conifer forest slash in the Sierra Nevada foothills for use as fuel in a biomass power cogeneration facility. Compared with the traditional open pile burning method of disposal for the forest harvest slash, utilization of the slash for fuel reduced particulate matter (PM) emissions by 98% (6 kg PM/BDT biomass), nitrogen oxides (NOx) by 54% (1.6 kg NOx/BDT), nonmethane volatile organics (NMOCs) by 99% (4.7 kg NMOCs/BDT), carbon monoxide (CO) by 97% (58 kg CO/BDT), and carbon dioxide equivalents (CO2e) by 17% (0.38 t CO2e/BDT). Emission contributions from biomass processing and transport operations are negligible. CO2e benefits are dependent on the emission characteristics of the displaced marginal electricity supply. Monetization of emissions reductions will assist with fuel sourcing activities and the conduct of biomass energy projects.

  8. Multifunctional Low-Pressure Turbine for Core Noise Reduction, Improved Efficiency, and Nitrogen Oxide (NOx) Reduction

    NASA Technical Reports Server (NTRS)

    Miller, Christopher J.; Shyam, Vikram; Rigby, David L.

    2013-01-01

    This work studied the feasibility of using Helmholtz resonator cavities embedded in low-pressure-turbine (LPT) airfoils to (1) reduce core noise by damping acoustic modes; (2) use the synthetic jets produced by the liner hole acoustic oscillations to improve engine efficiency by maintaining turbulent attached flow in the LPT at low-Reynolds-number cruise conditions; and (3) reduce engine nitrogen oxide emissions by lining the internal cavities with materials capable of catalytic conversion. Flat plates with embedded Helmholtz resonators, designed to resonate at either 3000 or at 400 Hz, were simulated using computational fluid dynamics. The simulations were conducted for two inlet Mach numbers, 0.25 and 0.5, corresponding to Reynolds numbers of 90 000 and 164 000 based on the effective chordwise distance to the resonator orifice. The results of this study are (1) the region of acoustic treatment may be large enough to have a benefit; (2) the jets may not possess sufficient strength to reduce flow separation (based on prior work by researchers in the flow control area); and (3) the additional catalytic surface area is not exposed to a high velocity, so it probably does not have any benefit.

  9. 40 CFR Appendix E to Part 75 - Optional NOX Emissions Estimation Protocol for Gas-Fired Peaking Units and Oil-Fired Peaking Units

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 17 2014-07-01 2014-07-01 false Optional NOX Emissions Estimation... MONITORING Pt. 75, App. E Appendix E to Part 75—Optional NOX Emissions Estimation Protocol for Gas-Fired Peaking Units and Oil-Fired Peaking Units 1. Applicability 1.1 Unit Operation Requirements This...

  10. 40 CFR 60.4325 - What emission limits must I meet for NOX if my turbine burns both natural gas and distillate oil...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... NOX if my turbine burns both natural gas and distillate oil (or some other combination of fuels)? 60... Combustion Turbines Emission Limits § 60.4325 What emission limits must I meet for NOX if my turbine burns... burning that fuel. Similarly, when your total heat input is greater than 50 percent distillate oil...

  11. Full-Scale Demonstration Low-NOx Cell Burner retrofit

    SciTech Connect

    Not Available

    1991-05-24

    The overall objective of the Full-Scale Low-NOx Cell (LNC) Burner Retrofit project is to demonstrate the cost-effective reduction of NOx generated by a large, base-loaded (70% capacity factor or greater), coal-fired utility boiler. Specific objectives include: at least 50% NOx reduction over standard two-nozzle cell burners, without degradation of boiler performance or life; acquire and evaluate emission and boiler performance data before and after the retrofit to determine NOx reduction and impact on overall boiler performance; and demonstrate that the LNC burner retrofits are the most cost-effective alternative to emerging, or commercially- available NOx control technology for units equipped with cell burners. The focus of this demonstration is to determine maximum NOx reduction capabilities without adversely impacting plant performance, operation and maintenance.

  12. New operation strategy for driving the selectivity of NOx reduction to N2, NH3 or N2O during lean/rich cycling of a lean NOx trap catalyst

    DOE PAGESBeta

    Mráček, David; Koci, Petr; Choi, Jae -Soon; Partridge, Jr., William P.

    2015-09-08

    Periodical regeneration of NOx storage catalyst (also known as lean NOx trap) by short rich pulses of CO, H2 and hydrocarbons is necessary for the reduction of nitrogen oxides adsorbed on the catalyst surface. Ideally, the stored NOx is converted into N2, but N2O and NH3 by-products can be formed as well, particularly at low-intermediate temperatures. The N2 and N2O products are formed concurrently in two peaks. The primary peaks appear immediately after the rich-phase inception, and tail off with the breakthrough of the reductant front accompanied by NH3 product. In addition, the secondary N2 and N2O peaks then appearmore » at the rich-to-lean transition as a result of reactions between surface-deposited reductants/intermediates (CO, HC, NH3, — NCO) and residual stored NOx under increasingly lean conditions.« less

  13. Measurements of real-world vehicle CO and NOx fleet average emissions in urban tunnels of two cities in China

    NASA Astrophysics Data System (ADS)

    Deng, Yiwen; Chen, Chao; Li, Qiong; Hu, Qinqiang; Yuan, Haoting; Li, Junmei; Li, Yan

    2015-12-01

    Urban tunnels located in the city center areas, can alleviate traffic pressure and provide more convenient traffic for people. Vehicles emit pollutants that are significant contributors to air pollution inside and at the outlet of tunnels. Ventilation is the most widely used method to dilute pollutants in tunnels. To calculate the design required air volume flow accurately, vehicle emissions should be exactly determined. Emission factors are important parameters to estimate vehicle emissions. To characterize carbon monoxide (CO) and nitrogen oxides (NOX) emission factors for a mixed vehicle fleet under real-world driving conditions of urban China, we measured CO and NOX concentrations in Shanghai East Yan'an Road tunnel and Changsha Yingpan Road tunnel in 2012 and 2013. In-use fleet average CO and NOX emission factors were calculated according to tunnel pollutants mass balance models. The results showed that the maximum CO concentration in August was 86 ppm, while in October it was 45 ppm in Shanghai East Yan'an Road tunnel. The maximum concentrations of CO and NOX were 33 ppm and 2 ppm in Changsha Yingpan Road tunnel, respectively. In-use fleet average CO emission factors of East Yan'an Road tunnel, with gradient of -3% ∼ 3%, were 1.266 (±0.889) ∼ 3.974 (±2.189) g km-1 vehicle-1. In-use fleet average CO and NOX emission factors of Yingpan Road tunnel with gradient of -6% ∼ 6% amounted to 0.754 (±0.561) ∼ 6.050 (±5.940) g km-1 vehicle-1 and 0.121 (±0.022) ∼ 0.818 (±0.755) g km-1 vehicle-1, respectively. The dependences of CO and NOX emission on roadway gradient and vehicle speed were found. The average CO and NOX emission factors increased with the ascending of roadway gradient as well as reverse with vehicle speed. These findings provide meaningful reference for ventilation design and environmental assessment of urban tunnels, and further help provide basic data to formulate relevant standards and norms.

  14. Promotional mechanism of propane on selective catalytic reduction of NOx by methane over In/H-BEA at low temperature

    NASA Astrophysics Data System (ADS)

    Pan, Hua; Jian, Yanfei; Yu, Yanke; Chen, Ningna; He, Chi; He, Cheng

    2016-12-01

    Effects of propane/methane ratios on NOx reduction by mixtures of methane and propane over In/H-BEA catalyst were investigated at temperatures ranging from 250 to 550 °C. The higher catalytic activity of In/H-BEA was exhibited for CH4-SCR at high temperatures above 450 °C, while the higher NOx conversion was achieved in C3H8-SCR at below 425 °C. A broadened temperature window and enhanced CO2 selectivity were achieved by combining of methane and propane as the co-reductant. The mixtures with propane/methane of 1/2 showed the most superior T50 (325 °C) and T90 (500 °C) temperatures for NOx reduction over In/H-BEA catalyst. For the promotion mechanism of propane on NO reduction by methane at low temperature, the formation of carbonaceous species (e.g. R-COOH) were enhanced by the activation of C3H8 on Brønsted acid sites at low temperature, and further promoted the generation of sbnd NCO species, which was a crucial determining step for NO reduction.

  15. Method for control of NOx emission from combustors using fuel dilution

    SciTech Connect

    Schefer, Robert W.; Keller, Jay O

    2007-01-16

    A method of controlling NOx emission from combustors. The method involves the controlled addition of a diluent such as nitrogen or water vapor, to a base fuel to reduce the flame temperature, thereby reducing NOx production. At the same time, a gas capable of enhancing flame stability and improving low temperature combustion characteristics, such as hydrogen, is added to the fuel mixture. The base fuel can be natural gas for use in industrial and power generation gas turbines and other burners. However, the method described herein is equally applicable to other common fuels such as coal gas, biomass-derived fuels and other common hydrocarbon fuels. The unique combustion characteristics associated with the use of hydrogen, particularly faster flame speed, higher reaction rates, and increased resistance to fluid-mechanical strain, alter the burner combustion characteristics sufficiently to allow operation at the desired lower temperature conditions resulting from diluent addition, without the onset of unstable combustion that can arise at lower combustor operating temperatures.

  16. Spatial representation of a current NOx emission inventory over China: A satellite perspective

    NASA Astrophysics Data System (ADS)

    Geng, G.; Zhang, Q.; Wang, S.; He, K.; Martin, R. V.; Lamsal, L. N.; Zheng, B.

    2012-12-01

    The top-down approach provides valuable constraints to bottom-up emission inventories. In this work, we evaluated the spatial representation of a current NOx emission inventory over China using NO2 retrievals from the Ozone Monitoring Instrument (OMI) and the nested-grid GEOS-Chem model. Comparison between model simulations and satellite observations showed that modeled NO2 columns were underestimated in most medium-sized cities, while good agreement was found in megacities such as Beijing, Shanghai. Large discrepancies between model simulations and satellite retrievals were found in grids with high Gross domestic product (GDP) value across different regions of China. We also found that the growth rates of NO2 columns have slowed in Chinese megacities over recent years, in contrast with medium-sized cities where the NO2 columns were soaring. Sensitivity simulations using emissions allocated by different spatial surrogates (e.g. population density, location, nighttime light, industrial GDP, road networks) indicated that the uncertainties in spatial representation of the current emission inventory might be caused by inappropriate spatial proxies.

  17. Air quality modelling : effects of emission reductions on concentrations of particulate matter

    NASA Astrophysics Data System (ADS)

    Girault, L.; Roustan, Y.; Seigneur, C.

    2012-04-01

    Atmospheric particulate matter (PM) has adverse effects on human health. PM acts primarily on respiratory and cardiovascular (due to their small size they can penetrate deep into the lungs), but they are also known effects on the skin. In France, the "Particulate Plan" - developed as part of the second National Environmental Health Plan - aims to reduce by 30% fine PM (noted PM2.5because these particles have an aerodynamic diameter of 2.5 micrometers or less) by 2015. A recent study by Airparif (the organization in charge of monitoring air quality in the Paris region, the Île-de-France) and LSCE (Laboratory of climate and the environmental science, France) has allowed, through a large measurement campaign conducted between 2009 and 2011, to quantify the proportion of PM produced in Île-de-France and those transported from the surrounding areas. The study by numerical modelling of air pollution presented here complements these results by investigating future emission scenarios. The CEREA develops and uses an air quality model which simulates the concentrations of pollutants from an emission inventory, meteorological data and boundary conditions of the area studied. After an evaluation of simulation results for the year 2005, the model is used to assess the effects of various scenarios of reductions in NOx and NH3 emissions on the concentrations of PM2.5in Île-de-France. The effects of the controls on the local pollution and the long-range pollution are considered separately. For each emitted species, three scenarios of emission reductions are identified: an emission reduction at the local level (Île-de-France), a reduction at the regional scale (France) and a reduction at the continental scale (across Europe). In each case, a 15% reduction is applied. The comparison of the results allows us to assess the respective contributions of local emissions and long-range transport to PM2.5 concentrations. For instance, the reduction of NOx emissions in Europe leads to a

  18. Intake fraction of PM2.5 and NOX from vehicle emissions in Beijing based on personal exposure data

    NASA Astrophysics Data System (ADS)

    Du, Xuan; Wu, Ye; Fu, Lixin; Wang, Shuxiao; Zhang, Shaojun; Hao, Jiming

    2012-09-01

    The intake fraction (iF) is the portion of attributable population intake of a source emissions, and is used to link pollutant emissions and population exposure. This study is the first work that reported individual intake fraction of PM2.5 and NOX from vehicle emissions based on personal exposure data in China. We employed PM2.5 and NOX measurement data from 24-h personal exposure sampling and concentration monitoring in traffic environments in the urban area of Beijing to estimate the individual intake fraction (iFi). iFi distributions are presented in microenvironments (traffic, work, home) for adults and children. The individual results are used to calculate the intake fraction for the children group and the adults group in the urban area of Beijing. The iF of PM2.5 for the whole population of these two groups in Beijing is 153 per million, which is significantly higher than those estimates in the United States (1-50 per million) and Mexico (23-120 per million). The iF of NOX is 70 per million, among which the intake in the traffic micro-environment ranks first compared to the iF in the home and office due to a high accumulation of NOX concentration in vehicles. PM2.5 and NOX intake fraction values from vehicle emissions in this study are from at least several times to one order of magnitude higher than those from other industry sources in China. This strongly suggests the health risk from vehicle emissions is significantly higher. Therefore, to protect human health, especially for the large number of people living in the cities of China, controlling vehicle emissions should be the highest priority.

  19. Inverse modeling of Texas NOx emissions using space-based and ground-based NO2 observations

    NASA Astrophysics Data System (ADS)

    Tang, W.; Cohan, D. S.; Lamsal, L. N.; Xiao, X.; Zhou, W.

    2013-11-01

    Inverse modeling of nitrogen oxide (NOx) emissions using satellite-based NO2 observations has become more prevalent in recent years, but has rarely been applied to regulatory modeling at regional scales. In this study, OMI satellite observations of NO2 column densities are used to conduct inverse modeling of NOx emission inventories for two Texas State Implementation Plan (SIP) modeling episodes. Addition of lightning, aircraft, and soil NOx emissions to the regulatory inventory narrowed but did not close the gap between modeled and satellite-observed NO2 over rural regions. Satellite-based top-down emission inventories are created with the regional Comprehensive Air Quality Model with extensions (CAMx) using two techniques: the direct scaling method and discrete Kalman filter (DKF) with decoupled direct method (DDM) sensitivity analysis. The simulations with satellite-inverted inventories are compared to the modeling results using the a priori inventory as well as an inventory created by a ground-level NO2-based DKF inversion. The DKF inversions yield conflicting results: the satellite-based inversion scales up the a priori NOx emissions in most regions by factors of 1.02 to 1.84, leading to 3-55% increase in modeled NO2 column densities and 1-7 ppb increase in ground 8 h ozone concentrations, while the ground-based inversion indicates the a priori NOx emissions should be scaled by factors of 0.34 to 0.57 in each region. However, none of the inversions improve the model performance in simulating aircraft-observed NO2 or ground-level ozone (O3) concentrations.

  20. Inverse modeling of Texas NOx emissions using space-based and ground-based NO2 observations

    NASA Astrophysics Data System (ADS)

    Tang, W.; Cohan, D.; Lamsal, L. N.; Xiao, X.; Zhou, W.

    2013-07-01

    Inverse modeling of nitrogen oxide (NOx) emissions using satellite-based NO2 observations has become more prevalent in recent years, but has rarely been applied to regulatory modeling at regional scales. In this study, OMI satellite observations of NO2 column densities are used to conduct inverse modeling of NOx emission inventories for two Texas State Implementation Plan (SIP) modeling episodes. Addition of lightning, aircraft, and soil NOx emissions to the regulatory inventory narrowed but did not close the gap between modeled and satellite observed NO2 over rural regions. Satellite-based top-down emission inventories are created with the regional Comprehensive Air Quality Model with extensions (CAMx) using two techniques: the direct scaling method and discrete Kalman filter (DKF) with Decoupled Direct Method (DDM) sensitivity analysis. The simulations with satellite-inverted inventories are compared to the modeling results using the a priori inventory as well as an inventory created by a ground-level NO2 based DKF inversion. The DKF inversions yield conflicting results: the satellite-based inversion scales up the a priori NOx emissions in most regions by factors of 1.02 to 1.84, leading to 3-55% increase in modeled NO2 column densities and 1-7 ppb increase in ground 8 h ozone concentrations, while the ground-based inversion indicates the a priori NOx emissions should be scaled by factors of 0.34 to 0.57 in each region. However, none of the inversions improve the model performance in simulating aircraft-observed NO2 or ground-level ozone (O3) concentrations.

  1. Inverse Modeling of Texas NOx Emissions Using Space-Based and Ground-Based NO2 Observations

    NASA Technical Reports Server (NTRS)

    Tang, Wei; Cohan, D.; Lamsal, L. N.; Xiao, X.; Zhou, W.

    2013-01-01

    Inverse modeling of nitrogen oxide (NOx) emissions using satellite-based NO2 observations has become more prevalent in recent years, but has rarely been applied to regulatory modeling at regional scales. In this study, OMI satellite observations of NO2 column densities are used to conduct inverse modeling of NOx emission inventories for two Texas State Implementation Plan (SIP) modeling episodes. Addition of lightning, aircraft, and soil NOx emissions to the regulatory inventory narrowed but did not close the gap between modeled and satellite observed NO2 over rural regions. Satellitebased top-down emission inventories are created with the regional Comprehensive Air Quality Model with extensions (CAMx) using two techniques: the direct scaling method and discrete Kalman filter (DKF) with Decoupled Direct Method (DDM) sensitivity analysis. The simulations with satellite-inverted inventories are compared to the modeling results using the a priori inventory as well as an inventory created by a ground-level NO2 based DKF inversion. The DKF inversions yield conflicting results: the satellite based inversion scales up the a priori NOx emissions in most regions by factors of 1.02 to 1.84, leading to 3-55% increase in modeled NO2 column densities and 1-7 ppb increase in ground 8 h ozone concentrations, while the ground-based inversion indicates the a priori NOx emissions should be scaled by factors of 0.34 to 0.57 in each region. However, none of the inversions improve the model performance in simulating aircraft-observed NO2 or ground-level ozone (O3) concentrations.

  2. 40 CFR 86.1861-17 - How do the NMOG+NOX and evaporative emission credit programs work?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...) in model year 2017. (c) The credit-deficit provisions 40 CFR 1037.745 apply to the NMOG+NOX and... PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES General Compliance Provisions for Control of Air Pollution From New and In-Use...

  3. 40 CFR 75.72 - Determination of NOX mass emissions for common stack and multiple stack configurations.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... lbs) by multiplying the hourly NOX emission rate (in lbs/mmBtu) by the hourly heat input rate (in mm... determining the hourly unit heat input rates, either: (i) Apportion the common stack heat input rate to the... this part, (A) Use the procedures in appendix D to this part to determine heat input rate for that...

  4. Performance of High Temperature Air Combustion Boiler with Low NOx Emission

    NASA Astrophysics Data System (ADS)

    Kobayashi, Hiromichi; Ito, Yoshihito; Tsuruta, Naoki; Yoshikawa, Kunio

    Thermal performance in the experiments and three-dimensional numerical simulations for a high temperature air combustion boiler where fuel can be efficiently combusted by high temperature preheated air (800°C-1000°C) is examined. The boiler can burn not only natural gas but also low calorific gas (e. g. full gasification gas obtained from coal or wastes). In the boiler, four regenerative burners are installed. This boiler has new features that not only air but also gasification gas is heated up to 900°C, and combination of burners is switched every 15 seconds where two burners are used as inlets of fuel and air and the other two burners are used as outlets of exhaust gas. Natural gas and syngas obtained from coal are burned. The NOx emission for each fuel is less than 50ppm. The heat transfer of three-dimensional calculation is predicted higher than that of experiment.

  5. Vortex combustor for low NOX emissions when burning lean premixed high hydrogen content fuel

    DOEpatents

    Steele, Robert C; Edmonds, Ryan G; Williams, Joseph T; Baldwin, Stephen P

    2012-11-20

    A trapped vortex combustor. The trapped vortex combustor is configured for receiving a lean premixed gaseous fuel and oxidant stream, where the fuel includes hydrogen gas. The trapped vortex combustor is configured to receive the lean premixed fuel and oxidant stream at a velocity which significantly exceeds combustion flame speed in a selected lean premixed fuel and oxidant mixture. The combustor is configured to operate at relatively high bulk fluid velocities while maintaining stable combustion, and low NOx emissions. The combustor is useful in gas turbines in a process of burning synfuels, as it offers the opportunity to avoid use of diluent gas to reduce combustion temperatures. The combustor also offers the possibility of avoiding the use of selected catalytic reaction units for removal of oxides of nitrogen from combustion gases exiting a gas turbine.

  6. Vortex combustor for low NOx emissions when burning lean premixed high hydrogen content fuel

    DOEpatents

    Steele, Robert C.; Edmonds, Ryan G.; Williams, Joseph T.; Baldwin, Stephen P.

    2009-10-20

    A trapped vortex combustor. The trapped vortex combustor is configured for receiving a lean premixed gaseous fuel and oxidant stream, where the fuel includes hydrogen gas. The trapped vortex combustor is configured to receive the lean premixed fuel and oxidant stream at a velocity which significantly exceeds combustion flame speed in a selected lean premixed fuel and oxidant mixture. The combustor is configured to operate at relatively high bulk fluid velocities while maintaining stable combustion, and low NOx emissions. The combustor is useful in gas turbines in a process of burning synfuels, as it offers the opportunity to avoid use of diluent gas to reduce combustion temperatures. The combustor also offers the possibility of avoiding the use of selected catalytic reaction units for removal of oxides of nitrogen from combustion gases exiting a gas turbine.

  7. Methods for reduction of charging emissions

    SciTech Connect

    Schuecker, F.J.; Schulte, H.

    1997-12-31

    One of the most critical subjects in coking plants are charging emissions. The paper reviews the systems that have been used over the years to reduce charging emissions. The advantages and disadvantages are summarized for the following systems: Double collecting main with aspiration on both oven sides; Single collecting main with/without aspiration via standpipe, and extraction and cleaning of charging gas on charging car; Single collecting main with aspiration via standpipe and pretreatment of charging gas on the charging car as well as additional stationary exhaust and cleaning of charging gas; Single collecting main with aspiration via single standpipe; and Single collecting main with simultaneous aspiration via two standpipes and a U-tube connecting the oven chamber with the neighboring oven. The paper then briefly discusses prerequisites for reduction of charging emissions.

  8. METHANE de-NOX FOR UTILITY PC BOILERS

    SciTech Connect

    Joseph Rabovitser

    2001-01-30

    The overall project objective is the development and validation of an innovative combustion system, based on a novel coal preheating concept prior to combustion, that can reduce NOx emissions to 0.15 lb/million Btu or less on utility pulverized coal (PC) boilers. This NOx reduction should be achieved without loss of boiler efficiency or operating stability, and at more than 25% lower levelized cost than state-of-the-art SCR technology. A further objective is to make this technology ready for full-scale commercial deployment by 2002-2003 in order to meet an anticipated market demand for NOx reduction technologies resulting from the EPA's NOx SIP call.

  9. Multi-satellite sensor study on precipitation-induced emission pulses of NOx from soils in semi-arid ecosystems

    NASA Astrophysics Data System (ADS)

    Zörner, Jan; Penning de Vries, Marloes; Beirle, Steffen; Sihler, Holger; Veres, Patrick R.; Williams, Jonathan; Wagner, Thomas

    2016-07-01

    We present a top-down approach to infer and quantify rain-induced emission pulses of NOx ( ≡ NO + NO2), stemming from biotic emissions of NO from soils, from satellite-borne measurements of NO2. This is achieved by synchronizing time series at single grid pixels according to the first day of rain after a dry spell of prescribed duration. The full track of the temporal evolution several weeks before and after a rain pulse is retained with daily resolution. These are needed for a sophisticated background correction, which accounts for seasonal variations in the time series and allows for improved quantification of rain-induced soil emissions. The method is applied globally and provides constraints on pulsed soil emissions of NOx in regions where the NOx budget is seasonally dominated by soil emissions. We find strong peaks of enhanced NO2 vertical column densities (VCDs) induced by the first intense precipitation after prolonged droughts in many semi-arid regions of the world, in particular in the Sahel. Detailed investigations show that the rain-induced NO2 pulse detected by the OMI (Ozone Monitoring Instrument), GOME-2 and SCIAMACHY satellite instruments could not be explained by other sources, such as biomass burning or lightning, or by retrieval artefacts (e.g. due to clouds). For the Sahel region, absolute enhancements of the NO2 VCDs on the first day of rain based on OMI measurements 2007-2010 are on average 4 × 1014  molec cm-2 and exceed 1 × 1015  molec cm-2 for individual grid cells. Assuming a NOx lifetime of 4 h, this corresponds to soil NOx emissions in the range of 6 up to 65 ng N m-2 s-1, which is in good agreement with literature values. Apart from the clear first-day peak, NO2 VCDs are moderately enhanced (2 × 1014  molec cm-2) compared to the background over the following 2 weeks, suggesting potential further emissions during that period of about 3.3 ng N m-2 s-1

  10. Emissions of NOx, particle mass and particle numbers from aircraft main engines, APU's and handling equipment at Copenhagen Airport

    NASA Astrophysics Data System (ADS)

    Winther, Morten; Kousgaard, Uffe; Ellermann, Thomas; Massling, Andreas; Nøjgaard, Jacob Klenø; Ketzel, Matthias

    2015-01-01

    This paper presents a detailed emission inventory for NOx, particle mass (PM) and particle numbers (PN) for aircraft main engines, APU's and handling equipment at Copenhagen Airport (CPH) based on time specific activity data and representative emission factors for the airport. The inventory has a high spatial resolution of 5 m × 5 m in order to be suited for further air quality dispersion calculations. Results are shown for the entire airport and for a section of the airport apron area ("inner apron") in focus. The methodology presented in this paper can be used to quantify the emissions from aircraft main engines, APU and handling equipment in other airports. For the entire airport, aircraft main engines is the largest source of fuel consumption (93%), NOx, (87%), PM (61%) and PN (95%). The calculated fuel consumption [NOx, PM, PN] shares for APU's and handling equipment are 5% [4%, 8%, 5%] and 2% [9%, 31%, 0%], respectively. At the inner apron area for handling equipment the share of fuel consumption [NOx, PM, PN] are 24% [63%, 75%, 2%], whereas APU and main engines shares are 43% [25%, 19%, 54%], and 33% [11%, 6%, 43%], respectively. The inner apron NOx and PM emission levels are high for handling equipment due to high emission factors for the diesel fuelled handling equipment and small for aircraft main engines due to small idle-power emission factors. Handling equipment is however a small PN source due to the low number based emission factors. Jet fuel sulphur-PM sensitivity calculations made in this study with the ICAO FOA3.0 method suggest that more than half of the PM emissions from aircraft main engines at CPH originate from the sulphur content of the fuel used at the airport. Aircraft main engine PN emissions are very sensitive to the underlying assumptions. Replacing this study's literature based average emission factors with "high" and "low" emission factors from the literature, the aircraft main engine PN emissions were estimated to change with a

  11. Greenhouse gas and criteria emission benefits through reduction of vessel speed at sea.

    PubMed

    Khan, M Yusuf; Agrawal, Harshit; Ranganathan, Sindhuja; Welch, William A; Miller, J Wayne; Cocker, David R

    2012-11-20

    Reducing emissions from ocean-going vessels (OGVs) as they sail near populated areas is a widely recognized goal, and Vessel Speed Reduction (VSR) is one of several strategies that is being adopted by regulators and port authorities. The goal of this research was to measure the emission benefits associated with greenhouse gas and criteria pollutants by operating OGVs at reduced speed. Emissions were measured from one Panamax and one post-Panamax class container vessels as their vessel speed was reduced from cruise to 15 knots or below. VSR to 12 knots yielded carbon dioxide (CO(2)) and nitrogen oxides (NO(x)) emissions reductions (in kg/nautical mile (kg/nmi)) of approximately 61% and 56%, respectively, as compared to vessel cruise speed. The mass emission rate (kg/nmi) of PM(2.5) was reduced by 69% with VSR to 12 knots alone and by ~97% when coupled with the use of the marine gas oil (MGO) with 0.00065% sulfur content. Emissions data from vessels while operating at sea are scarce and measurements from this research demonstrated that tidal current is a significant parameter affecting emission factors (EFs) at lower engine loads. Emissions factors at ≤20% loads calculated by methodology adopted by regulatory agencies were found to underestimate PM(2.5) and NO(x) by 72% and 51%, respectively, when compared to EFs measured in this study. Total pollutant emitted (TPE) in the emission control area (ECA) was calculated, and emission benefits were estimated as the VSR zone increased from 24 to 200 nmi. TPE(CO2) and TPE(PM2.5) estimated for large container vessels showed benefits for CO(2) (2-26%) and PM(2.5) (4-57%) on reducing speeds from 15 to 12 knots, whereas TPE(CO2) and TPE(PM2.5) for small and medium container vessels were similar at 15 and 12 knots.

  12. An enhanced rate-based emission trading program for NOX: the Dutch model.

    PubMed

    Sholtz, A M; Van Amburg, B; Wochnick, V K

    2001-12-01

    Since 1997 government and industry in The Netherlands have been engaged in intensive policy discussions on how to design an emission trading program that would satisfy the Government's policy objectives within the national and international regulatory framework and accommodate industry's need for a flexible and cost-effective approach. Early on in the discussion the most promising solution was a rate-based approach, which dynamically allocated saleable emission credits based on a performance standard rate and actual energy used by facilities. All industrial facilities above a threshold of 20 MWth would be judged on their ability to meet this performance rate. Those "cleaner" than the standard can sell excess credits to others with an allocation that is less than their actual NOX emission. With some changes in law, such a design could be made to fit well into the national and EU legislative framework while at the same time uniquely meeting industry's requirement of flexibility toward economic growth and facility expansion. (An analysis of the legislative changes required will be given in a separate paper by Chris Dekkers.) However, the environmental outcome of such a system is not as certain as under an absolute emission cap. At the request of the Netherlands Ministry of Housing, Spatial Planning and the Environment (VROM), Automated Credit Exchange (ACE), in close cooperation with the working group of government and industry representatives introduced a number of features into the Dutch NOX program allowing full exploitation of market mechanisms while allowing intermediate adjustments in the performance standard rates. The design is geared toward meeting environmental targets without jeopardizing the trading market the program intends to create. The paper discusses the genesis of the two-tier credit system ACE helped to design, explains the differences between primary (fixed) and secondary (variable) credits, and outlines how the Dutch system is expected to

  13. An enhanced rate-based emission trading program for NOX: the Dutch model.

    PubMed

    Sholtz, A M; Van Amburg, B; Wochnick, V K

    2001-12-01

    Since 1997 government and industry in The Netherlands have been engaged in intensive policy discussions on how to design an emission trading program that would satisfy the Government's policy objectives within the national and international regulatory framework and accommodate industry's need for a flexible and cost-effective approach. Early on in the discussion the most promising solution was a rate-based approach, which dynamically allocated saleable emission credits based on a performance standard rate and actual energy used by facilities. All industrial facilities above a threshold of 20 MWth would be judged on their ability to meet this performance rate. Those "cleaner" than the standard can sell excess credits to others with an allocation that is less than their actual NOX emission. With some changes in law, such a design could be made to fit well into the national and EU legislative framework while at the same time uniquely meeting industry's requirement of flexibility toward economic growth and facility expansion. (An analysis of the legislative changes required will be given in a separate paper by Chris Dekkers.) However, the environmental outcome of such a system is not as certain as under an absolute emission cap. At the request of the Netherlands Ministry of Housing, Spatial Planning and the Environment (VROM), Automated Credit Exchange (ACE), in close cooperation with the working group of government and industry representatives introduced a number of features into the Dutch NOX program allowing full exploitation of market mechanisms while allowing intermediate adjustments in the performance standard rates. The design is geared toward meeting environmental targets without jeopardizing the trading market the program intends to create. The paper discusses the genesis of the two-tier credit system ACE helped to design, explains the differences between primary (fixed) and secondary (variable) credits, and outlines how the Dutch system is expected to

  14. Effects of co-processing sewage sludge in cement kiln on NOx, NH3 and PAHs emissions.

    PubMed

    Lv, Dong; Zhu, Tianle; Liu, Runwei; Lv, Qingzhi; Sun, Ye; Wang, Hongmei; Liu, Yu; Zhang, Fan

    2016-09-01

    The effects of co-processing sewage sludge in cement kiln on NOx, NH3 and PAHs emissions were systematically investigated in a cement production line in Beijing. The results show that co-processing the sewage sludge was helpful to reduce NOx emission, which primarily depends on the NH3 amount released from the sewage sludge. Meanwhile, NOx and NH3 concentrations in the flue gas have a negative correlation, and the contribution of feeding the sewage sludge to NOx removal decreased with the increase of injection amount of ammonia water in the SNCR system. Therefore, it is suggested that the injection amount of ammonia water in SNCR system may reduce to cut down the operating costs during co-processing the sewage sludge in cement kiln. In addition, the emission of total PAHs seems to increase with the increased amount of the sewage sludge feeding to the cement kiln. However, the distributions of PAHs were barely changed, and lower molecular weight PAHs were mainly distributed in gaseous phase, accounted for the major portion of PAHs when co-processing sewage sludge in cement kiln.

  15. Effects of co-processing sewage sludge in cement kiln on NOx, NH3 and PAHs emissions.

    PubMed

    Lv, Dong; Zhu, Tianle; Liu, Runwei; Lv, Qingzhi; Sun, Ye; Wang, Hongmei; Liu, Yu; Zhang, Fan

    2016-09-01

    The effects of co-processing sewage sludge in cement kiln on NOx, NH3 and PAHs emissions were systematically investigated in a cement production line in Beijing. The results show that co-processing the sewage sludge was helpful to reduce NOx emission, which primarily depends on the NH3 amount released from the sewage sludge. Meanwhile, NOx and NH3 concentrations in the flue gas have a negative correlation, and the contribution of feeding the sewage sludge to NOx removal decreased with the increase of injection amount of ammonia water in the SNCR system. Therefore, it is suggested that the injection amount of ammonia water in SNCR system may reduce to cut down the operating costs during co-processing the sewage sludge in cement kiln. In addition, the emission of total PAHs seems to increase with the increased amount of the sewage sludge feeding to the cement kiln. However, the distributions of PAHs were barely changed, and lower molecular weight PAHs were mainly distributed in gaseous phase, accounted for the major portion of PAHs when co-processing sewage sludge in cement kiln. PMID:27343866

  16. Relationship between VOC and NOx emissions and chemical production of tropospheric ozone in the Aburrá Valley (Colombia).

    PubMed

    Toro, María Victoria; Cremades, Lázaro V; Calbó, Josep

    2006-10-01

    Relationship between volatile organic compounds (VOC) and nitrogen oxides (NOx) emissions and the chemical production of tropospheric ozone is studied through mathematical simulation. The study is applied to the Aburrá Valley, in the Colombian Andes, which is a practically unknown area from the point of view of ozone formation. The model used for this application is the European modelling of atmospheric constituents (EUMAC) zooming model (EZM) which consists of a mesoscale prognostic model (MEMO, mesoscale meteorological model) and a chemical reaction model (MUSE, multiscale for the atmospheric dispersion of reactive species), coupled to the chemical mechanism EMEP (European monitoring and evaluation program). The analysis is performed for a real episode that was characterized by high ozone production and that happened during the 23rd and 24th December, 1999 in Medellín (Colombia). From this real scenario, a sensitivity analysis has been carried out in order to assess the influence of VOC and NOx amounts on ozone production and to extract some conclusions for future ozone abatement policies in Andean regions. As far as ozone air quality is concerned, it is shown that in order to keep current levels the emphasis must be put to avoid increasing NOx emissions, or alternatively, to augment VOC emissions in order to have a high VOC/NOx ratio. PMID:16631888

  17. Measurement of ethylene emission from Japanese red pine (Pinus densiflora) under field conditions in NOx-polluted areas.

    PubMed

    Kume, A; Tsuboi, N; Nakatani, N; Nakane, K; Sakurai, N; Nakagawa, N; Sakugawa, H

    2001-01-01

    Emission of ethylene from the needles of Japanese red pine, Pinus densiflora, was measured in air-polluted areas in Hiroshima, Japan. We applied a suitable protocol to determine the rate of ethylene emission from the excised needles. The influence of excision of needles on ethylene emission was not detected during the first 4 h of incubation at 20 degrees C. Ethylene emissions were low in the unpolluted (clean) areas regardless of the altitude or season. The emission of stress ethylene increased with the atmospheric NO2 concentration, suggesting that atmospheric NOx or related substances induced the higher ethylene emission in the polluted areas (near urban and industrial areas). In all cases, 1-year-old needles emitted significantly larger amounts of ethylene than the current needles. Ethylene emission did not increase evenly in the polluted areas, but the frequency of trees emitting high ethylene increased. Therefore, threshold rates for the baseline ethylene emission were proposed.

  18. Assessing the potential visibility benefits of Clean Air Act Title IV emission reductions

    SciTech Connect

    Trexler, E.C. Jr.; Shannon, J.D.

    1995-06-01

    Assessments are made of the benefits of the 1990 Clean Air Act Title IV (COVE), Phase 2, SO2 and NOX reduction provisions, to the visibility in typical eastern and western Class 1 areas. Probable bands of visibility impairment distribution curves are developed for Shenandoah National Park, Smoky Mountain National Park and the Grand Canyon National Park, based on the existing emissions, ``Base Case``, and for the COVE emission reductions, ``CAAA Case``. Emission projections for 2010 are developed with improved versions of the National Acid Precipitation Assessment Program emission projection models. Source-receptor transfer matrices created with the Advanced Statistical Trajectory Regional Air Pollution (ASTRAP) model are used with existing emission inventories and with the emission projections to calculate atmospheric concentrations of sulfate and nitrate at the receptors of interest for existing and projected emission scenarios. The Visibility Assessment Scoping Model (VASM) is then used to develop distributions of visibility impairment. VASM combines statistics of observed concentrations of particulate species and relative humidity with ASTRAP calculations of the relative changes in atmospheric sulfate and nitrate particulate concentrations in a Monte Carlo approach to produce expected distributions of hourly particulate concentrations and RH. Light extinction relationships developed in theoretical and field studies are then used to calculate the resulting distribution of visibility impairment. Successive Monte Carlo studies are carried out to develop sets of visibility impairment distributions with and without the COVE emission reductions to gain insight into the detectability of expected visibility improvements.

  19. Satellite NO2 retrievals suggest China has exceeded its NOx reduction goals from the twelfth Five-Year Plan

    PubMed Central

    de Foy, Benjamin; Lu, Zifeng; Streets, David G.

    2016-01-01

    China’s twelfth Five-Year Plan included pollution control measures with a goal of reducing national emissions of nitrogen oxides (NOx) by 10% by 2015 compared with 2010. Multiple linear regression analysis was used on 11-year time series of all nitrogen dioxide (NO2) pixels from the Ozone Monitoring Instrument (OMI) over 18 NO2 hotspots in China. The regression analysis accounted for variations in meteorology, pixel resolution, seasonal effects, weekday variability and year-to-year variability. The NO2 trends suggested that there was an increase in NO2 columns in most areas from 2005 to around 2011 which was followed by a strong decrease continuing through 2015. The satellite results were in good agreement with the annual official NOx emission inventories which were available up until 2014. This shows the value of evaluating trends in emission inventories using satellite retrievals. It further shows that recent control strategies were effective in reducing emissions and that recent economic transformations in China may be having an effect on NO2 columns. Satellite information for 2015 suggests that emissions have continued to decrease since the latest inventories available and have surpassed the goals of the twelfth Five-Year Plan. PMID:27786278

  20. Comparison of Weekly Cycle of NO2 Satellite Retrievals and NO(x) Emission Inventories for the Continental United States

    NASA Technical Reports Server (NTRS)

    Kaynak, B.; Hu, Y.; Martin, R. V.; Sioris, C. E.; Russell, A. G.

    2009-01-01

    Spatially resolved weekly NO2 variations are obtained from 2003 to 2005 Scanning Imaging Absorption Spectrometer for Atmospheric Cartography (SCIAMACHY) tropospheric NO2 columns for three different types of regions: urban, rural, and rural-point (rural with significant electricity generation unit (EGU) emissions). Regions are compared for magnitudes and weekly profiles. Rural regions do not show any weekly pattern, whereas urban areas show a distinct decrease on the weekends. Rural regions with EGUs show a slight decrease on Sundays. When compared with estimated mobile and stationary nitrogen oxides (NO(x)) emissions from the year 2004 for seven cities, the satellite data have greater variation during weekdays (Monday-Friday). Overall comparisons show that SCIAMACHY derived NO2 correlate well with estimated NO(x) emissions for urban and rural but less for rural-point regions.

  1. Estimates of the changes in tropospheric chemistry which result from human activity and their dependence on NO(x) emissions and model resolution

    NASA Technical Reports Server (NTRS)

    Kanakidou, Maria; Crutzen, Paul J.; Zimmermann, Peter H.

    1994-01-01

    As a consequence of the non-linear behavior of the chemistry of the atmosphere and because of the short lifetime of nitrogen oxides (NO(x)), two-dimensional models do not give an adequate description of the production and destruction rates of NO(x) and their effects on the distributions of the concentration of ozone and hydroxyl radical. In this study, we use a three-dimensional model to evaluate the contribution of increasing NO(x) emissions from industrial activity and biomass burning to changes in the chemical composition of the troposphere. By comparing results obtained from longitudinally-uniform and longitudinally-varying emissions of NO(x), we demonstrate that the geographical representation of the NO(x) emissions is crucial in simulating tropospheric chemistry.

  2. In situ FT-IR studies on the mechanism of selective catalytic reduction of NOx by propene over SnO2/Al2O3 catalyst.

    PubMed

    Liu, Zhiming; Woo, Seong Ihl; Lee, Won Su

    2006-12-28

    The mechanism of the selective catalytic reduction (SCR) of NOx by propene over SnO2/Al2O3 catalyst in the presence of oxygen has been investigated using in situ Fourier transform infrared (FT-IR) spectroscopy. In situ IR measurements indicate that acetate and formate, which are the derivatives of the partial oxidation of propene, play a crucial role in the formation of NCO by reacting with the reactive monodentate nitrate species. The resulting NCO species subsequently reacts with NOx to form N2. The presence of oxygen substantially contributes to the partial oxidation of propene and thus shows a promoting effect for the NOx reduction.

  3. 10 CFR 300.7 - Net emission reductions.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 3 2013-01-01 2013-01-01 false Net emission reductions. 300.7 Section 300.7 Energy DEPARTMENT OF ENERGY CLIMATE CHANGE VOLUNTARY GREENHOUSE GAS REPORTING PROGRAM: GENERAL GUIDELINES § 300.7 Net emission reductions. (a) Entities that intend to register emission reductions achieved must...

  4. 10 CFR 300.8 - Calculating emission reductions.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 3 2011-01-01 2011-01-01 false Calculating emission reductions. 300.8 Section 300.8 Energy DEPARTMENT OF ENERGY CLIMATE CHANGE VOLUNTARY GREENHOUSE GAS REPORTING PROGRAM: GENERAL GUIDELINES § 300.8 Calculating emission reductions. (a) Choosing appropriate emission reduction calculation...

  5. 10 CFR 300.8 - Calculating emission reductions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 3 2010-01-01 2010-01-01 false Calculating emission reductions. 300.8 Section 300.8 Energy DEPARTMENT OF ENERGY CLIMATE CHANGE VOLUNTARY GREENHOUSE GAS REPORTING PROGRAM: GENERAL GUIDELINES § 300.8 Calculating emission reductions. (a) Choosing appropriate emission reduction calculation...

  6. 10 CFR 300.7 - Net emission reductions.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 3 2014-01-01 2014-01-01 false Net emission reductions. 300.7 Section 300.7 Energy DEPARTMENT OF ENERGY CLIMATE CHANGE VOLUNTARY GREENHOUSE GAS REPORTING PROGRAM: GENERAL GUIDELINES § 300.7 Net emission reductions. (a) Entities that intend to register emission reductions achieved must...

  7. 10 CFR 300.7 - Net emission reductions.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 3 2011-01-01 2011-01-01 false Net emission reductions. 300.7 Section 300.7 Energy DEPARTMENT OF ENERGY CLIMATE CHANGE VOLUNTARY GREENHOUSE GAS REPORTING PROGRAM: GENERAL GUIDELINES § 300.7 Net emission reductions. (a) Entities that intend to register emission reductions achieved must...

  8. 10 CFR 300.8 - Calculating emission reductions.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 3 2013-01-01 2013-01-01 false Calculating emission reductions. 300.8 Section 300.8 Energy DEPARTMENT OF ENERGY CLIMATE CHANGE VOLUNTARY GREENHOUSE GAS REPORTING PROGRAM: GENERAL GUIDELINES § 300.8 Calculating emission reductions. (a) Choosing appropriate emission reduction calculation...

  9. 10 CFR 300.8 - Calculating emission reductions.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 3 2014-01-01 2014-01-01 false Calculating emission reductions. 300.8 Section 300.8 Energy DEPARTMENT OF ENERGY CLIMATE CHANGE VOLUNTARY GREENHOUSE GAS REPORTING PROGRAM: GENERAL GUIDELINES § 300.8 Calculating emission reductions. (a) Choosing appropriate emission reduction calculation...

  10. 10 CFR 300.8 - Calculating emission reductions.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 3 2012-01-01 2012-01-01 false Calculating emission reductions. 300.8 Section 300.8 Energy DEPARTMENT OF ENERGY CLIMATE CHANGE VOLUNTARY GREENHOUSE GAS REPORTING PROGRAM: GENERAL GUIDELINES § 300.8 Calculating emission reductions. (a) Choosing appropriate emission reduction calculation...

  11. 10 CFR 300.7 - Net emission reductions.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 3 2012-01-01 2012-01-01 false Net emission reductions. 300.7 Section 300.7 Energy DEPARTMENT OF ENERGY CLIMATE CHANGE VOLUNTARY GREENHOUSE GAS REPORTING PROGRAM: GENERAL GUIDELINES § 300.7 Net emission reductions. (a) Entities that intend to register emission reductions achieved must...

  12. 10 CFR 300.7 - Net emission reductions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 3 2010-01-01 2010-01-01 false Net emission reductions. 300.7 Section 300.7 Energy DEPARTMENT OF ENERGY CLIMATE CHANGE VOLUNTARY GREENHOUSE GAS REPORTING PROGRAM: GENERAL GUIDELINES § 300.7 Net emission reductions. (a) Entities that intend to register emission reductions achieved must...

  13. The effect of incomplete fuel-air mixing on the lean blowout limit, lean stability limit and NO(x) emissions in lean premixed gas turbine combustors

    NASA Technical Reports Server (NTRS)

    Shih, W.-P.; Lee, J. G.; Santavicca, D. A.

    1994-01-01

    Gas turbine engines for both land-based and aircraft propulsion applications are facing regulations on NOx emissions which cannot be met with current combustor technology. A number of alternative combustor strategies are being investigated which have the potential capability of achieving ultra-low NOx emissions, including lean premixed combustors, direct injection combustors, rich burn-quick quench-lean burn combustors and catalytic combustors. The research reported in this paper addresses the effect of incomplete fuel-air mixing on the lean limit performance and the NOx emissions characteristics of lean premixed combustors.

  14. Preparation of highly active manganese oxides supported on functionalized MWNTs for low temperature NOx reduction with NH3

    NASA Astrophysics Data System (ADS)

    Pourkhalil, Mahnaz; Moghaddam, Abdolsamad Zarringhalam; Rashidi, Alimorad; Towfighi, Jafar; Mortazavi, Yadollah

    2013-08-01

    Manganese oxide catalysts (MnOx) supported on functionalized multi-walled carbon nanotubes (FMWNTs) for low temperature selective catalytic reduction (LTSCR) of nitrogen oxides (NOx) with NH3 in the presence of excess O2 were prepared by the incipient wetness impregnation method. These catalysts were characterized by N2 adsorption, Fourier transform infrared spectroscopy (FTIR), transmission electron microscope (TEM), X-ray diffraction (XRD), thermal gravimetric analysis (TGA) and H2-temperature programmed reduction (H2-TPR) methods. The effects of reaction temperature, MnOx loading, calcination temperature and calcination time were investigated. The presence of surface nitrate species under moderate calcination conditions may play a favorable role in the LTSCR of NOx with NH3. Under the reaction conditions of 200 °C, 1 bar, NO = NH3 = 900 ppm, O2 = 5 vol%, GHSV = 30,000 h-1 and 12 wt% MnOx, NOx conversion and N2 selectivity were 97% and 99.5%, respectively. The SCR activity was reduced in the presence of 100 ppm SO2 and 2.5 vol% H2O from 97% to 92% within 6 h at 200 °C, however such an effect was shown to be reversible by exposing the catalyst to a helium flow for 2 h at 350 °C due to thermal decomposition of ammonium sulphate salts.

  15. Simulations of NOx Emissions from Low Emissions Discrete Jet Injector Combustor Tests

    NASA Technical Reports Server (NTRS)

    Ajmani, Kumud; Breisacher, Kevin

    2014-01-01

    An experimental and computational study was conducted to evaluate the performance and emissions characteristics of a candidate Lean Direct Injection (LDI) combustor configuration with a mix of simplex and airblast injectors. The National Combustion Code (NCC) was used to predict the experimentally measured EINOx emissions for test conditions representing low power, medium power, and high-power engine cycle conditions. Of the six cases modeled with the NCC using a reduced-kinetics finite-rate mechanism and lagrangian spray modeling, reasonable predictions of combustor exit temperature and EINOx were obtained at two high-power cycle conditions.

  16. Economic reduction of acidifying deposition in Finland by decreasing emissions in Finland, Estonia and Russia.

    PubMed

    Tähtinen, M; Lehtilä, A; Pipatti, R; Wistbacka, M; Savolainen, I

    1997-09-26

    Here we consider cost-effective solutions of emission control measures in Finland and the nearby areas of Estonia, St. Petersburg region, Karelia and Kola, in order to limit the acidifying deposition in Finland. In the study, the emission control costs of SO2, NOx and NH3 are assessed for the areas studied and an optimisation model developed for calculation of cost-optimal deposition control policies. The input data of the model consist of the cost functions describing the emission control costs to achieve lower emission levels for the gases and areas considered and of dispersion coefficients which describe the deposition due to an emission source in the deposition receptor grid squares. In addition, the model includes a description to calculate the acidifying load. The optimisation is based on linear programming. When the acidifying load of Southern Finland is reduced by minimising the total control costs, approx, three quarters of the total control costs are due to measures in the nearby areas, Estonia, St. Peterburg region, Karelia and Kola, and approx. one quarter due to measures in Finland. The distribution of costs in the cost-optimised cases depends relatively little on the level to which the acidifying load due the source areas considered are required to be reduced. If the load reduction target is moderate, the emission control measures should mainly be allocated to sulphur emissions and to some extent to ammonia emissions and, if the load reduction target is stricter, also to the emissions of nitrogen oxides.

  17. Observations of the Temperature Dependent Response of Ozone to NOx Reductions in an Urban Plume

    SciTech Connect

    LaFranchi, B W; Goldstein, A H; Cohen, R C

    2011-01-25

    Observations of NO{sub x} in the Sacramento, CA region show that mixing ratios decreased by 30% between 2001 and 2008. Here we use an observation-based method to quantify net ozone production rates in the outflow from the Sacramento metropolitan region and examine the O{sub 3} decrease resulting from reductions in NO{sub x} emissions. This observational method does not rely on assumptions about detailed chemistry of ozone production, rather it is an independent means to verify and test these assumptions. We use an instantaneous steady-state model as well as a detailed 1-D plume model to aid in interpretation of the ozone production inferred from observations. In agreement with the models, the observations show that early in the plume, the NO{sub x} dependence for O{sub x} (O{sub x} = O{sub 3}+NO{sub 2}) production is strongly coupled with temperature, suggesting that temperature dependent biogenic VOC emissions can drive O{sub x} production between NO{sub x}-limited and NO{sub x}-suppressed regimes. As a result, NO{sub x} reductions were found to be most effective at higher temperatures over the 7 year period. We show that violations of the California 1-hour O{sub 3} standard (90 ppb) in the region have been decreasing linearly with decreases in NO{sub x} (at a given temperature) and predict that reductions of NO{sub x} concentrations (and presumably emissions) by an additional 30% (relative to 2007 levels) will eliminate violations of the state 1 hour standard in the region. If current trends continue, a 30% decrease in NO{sub x} is expected by 2012, and an end to violations of the 1 hour standard in the Sacramento region appears to be imminent.

  18. Experimental study on the inhibition of biological reduction of Fe(III)EDTA in NOx absorption solution*

    PubMed Central

    Li, Wei; Wu, Cheng-zhi; Zhang, Shi-han; Shi, Yao; Lei, Le-cheng

    2005-01-01

    Scrubbing of NOx from the gas phase with Fe(II)EDTA has been shown to be highly effective. A new biological method can be used to convert NO to N2 and regenerate the chelating agent Fe(II)EDTA for continuous NO absorption. The core of this biological regeneration is how to effectively simultaneous reduce Fe(III)EDTA and Fe(II)EDTA-NO, two mainly products in the ferrous chelate absorption solution. The biological reduction rate of Fe(III)EDTA plays a main role for the NOx removal efficiency. In this paper, a bacterial strain identified as Klebsiella Trevisan sp. was used to demonstrate an inhibition of Fe(III)EDTA reduction in the presence of Fe(II)EDTA-NO. The competitive inhibition experiments indicted that Fe(II)EDTA-NO inhibited not only the growth rate of the iron-reduction bacterial strain but also the Fe(III)EDTA reduction rate. Cell growth rate and Fe(III)EDTA reduction rate decreased with increasing Fe(II)EDTA-NO concentration in the solution. PMID:16187414

  19. Diesel engine NOx reduction through exhaust re-burning and ammonia injection

    SciTech Connect

    Broadmeadow, J.T.; Ibrahim, O.M.

    1995-12-31

    This paper presents a chemical equilibrium analysis of a combination of Re-burn Combustion and Selective Non-Catalytic Reduction (SNCR), using a minimization of Gibbs energy and Lagrangian multipliers. A re-burning combustion chamber designed to reduce emissions from bus diesel engines has been developed with a possible modification to the chamber including the injection of ammonia into the combustion process. This chemical equilibrium study is performed to provide the theoretical possibilities of such a process. The results will show that significant NO{sub x} reduction could be achieved, with higher concentrations of ammonia leading to better results. CO and HCs will experience an initial decrease in concentrations, but will reach a critical point after which concentrations will rise due to ammonia slip across the combustion process.

  20. Attributing changes in atmospheric methane 1850-2000 to changes in CH4, NOx, CO, and NMVOC emissions (Invited)

    NASA Astrophysics Data System (ADS)

    Stevenson, D. S.

    2013-12-01

    Global atmospheric methane concentrations rose from 791 ppb in 1850 to 1751 ppb in 2000, with an associated radiative forcing (RF) of 427 mW m-2. This growth can be attributed to several factors - here we focus on changes in anthropogenic emissions of methane itself, but also on emissions of nitrogen oxides (NOx), carbon monoxide (CO) and non-methane hydrocarbons (NMVOC). Within the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP), six models conducted sensitivity experiments and found that CH4 emissions alone produced a CH4 RF of 533 mW m-2; other contributions (mW m-2) were: NOx, -312; CO, 58; and NMVOC, 35. These four numbers sum to 300, not 427, indicating that the RFs cannot be simply added, and that important interactions between emitted species have occurred. A further suite of sensitivity experiments were carried out with one of the ACCMIP models (STOC-HadAM3), changing combinations of emissions, to investigate these interactions in more detail. The largest sources of non-linearity are from interactions between emitted NOx and the other emitted species. These results indicate that a simple, individual species attribution of CH4 RF to emitted species is only approximately correct, and hides important interactions. These interactions will probably depend on individual model's chemical schemes, and they present a further difficulty in communicating robust results on short-lived climate forcing agents to policymakers.

  1. Nitrogen stable isotope composition (δ15N) of vehicle-emitted NOx.

    PubMed

    Walters, Wendell W; Goodwin, Stanford R; Michalski, Greg

    2015-02-17

    The nitrogen stable isotope ratio of NOx (δ(15)N-NOx) has been proposed as a regional indicator for NOx source partitioning; however, knowledge of δ(15)N values from various NOx emission sources is limited. This study presents a detailed analysis of δ(15)N-NOx emitted from vehicle exhaust, the largest source of anthropogenic NOx. To accomplish this, NOx was collected from 26 different vehicles, including gasoline and diesel-powered engines, using a modification of a NOx collection method used by the United States Environmental Protection Agency, and δ(15)N-NOx was analyzed. The vehicles sampled in this study emitted δ(15)N-NOx values ranging from -19.1 to 9.8‰ that negatively correlated with the emitted NOx concentrations (8.5 to 286 ppm) and vehicle run time because of kinetic isotope fractionation effects associated with the catalytic reduction of NOx. A model for determining the mass-weighted δ(15)N-NOx from vehicle exhaust was constructed on the basis of average commute times, and the model estimates an average value of -2.5 ± 1.5‰, with slight regional variations. As technology improvements in catalytic converters reduce cold-start emissions in the future, it is likely to increase current δ(15)N-NOx values emitted from vehicles. PMID:25621737

  2. Nitrogen stable isotope composition (δ15N) of vehicle-emitted NOx.

    PubMed

    Walters, Wendell W; Goodwin, Stanford R; Michalski, Greg

    2015-02-17

    The nitrogen stable isotope ratio of NOx (δ(15)N-NOx) has been proposed as a regional indicator for NOx source partitioning; however, knowledge of δ(15)N values from various NOx emission sources is limited. This study presents a detailed analysis of δ(15)N-NOx emitted from vehicle exhaust, the largest source of anthropogenic NOx. To accomplish this, NOx was collected from 26 different vehicles, including gasoline and diesel-powered engines, using a modification of a NOx collection method used by the United States Environmental Protection Agency, and δ(15)N-NOx was analyzed. The vehicles sampled in this study emitted δ(15)N-NOx values ranging from -19.1 to 9.8‰ that negatively correlated with the emitted NOx concentrations (8.5 to 286 ppm) and vehicle run time because of kinetic isotope fractionation effects associated with the catalytic reduction of NOx. A model for determining the mass-weighted δ(15)N-NOx from vehicle exhaust was constructed on the basis of average commute times, and the model estimates an average value of -2.5 ± 1.5‰, with slight regional variations. As technology improvements in catalytic converters reduce cold-start emissions in the future, it is likely to increase current δ(15)N-NOx values emitted from vehicles.

  3. Effects of a combined Diesel particle filter-DeNOx system (DPN) on reactive nitrogen compounds emissions: a parameter study.

    PubMed

    Heeb, Norbert V; Haag, Regula; Seiler, Cornelia; Schmid, Peter; Zennegg, Markus; Wichser, Adrian; Ulrich, Andrea; Honegger, Peter; Zeyer, Kerstin; Emmenegger, Lukas; Zimmerli, Yan; Czerwinski, Jan; Kasper, Markus; Mayer, Andreas

    2012-12-18

    The impact of a combined diesel particle filter-deNO(x) system (DPN) on emissions of reactive nitrogen compounds (RNCs) was studied varying the urea feed factor (α), temperature, and residence time, which are key parameters of the deNO(x) process. The DPN consisted of a platinum-coated cordierite filter and a vanadia-based deNO(x) catalyst supporting selective catalytic reduction (SCR) chemistry. Ammonia (NH₃) is produced in situ from thermolysis of urea and hydrolysis of isocyanic acid (HNCO). HNCO and NH₃ are both toxic and highly reactive intermediates. The deNO(x) system was only part-time active in the ISO8178/4 C1cycle. Urea injection was stopped and restarted twice. Mean NO and NO₂ conversion efficiencies were 80%, 95%, 97% and 43%, 87%, 99%, respectively, for α = 0.8, 1.0, and 1.2. HNCO emissions increased from 0.028 g/h engine-out to 0.18, 0.25, and 0.26 g/h at α = 0.8, 1.0, and 1.2, whereas NH₃ emissions increased from <0.045 to 0.12, 1.82, and 12.8 g/h with maxima at highest temperatures and shortest residence times. Most HNCO is released at intermediate residence times (0.2-0.3 s) and temperatures (300-400 °C). Total RNC efficiencies are highest at α = 1.0, when comparable amounts of reduced and oxidized compounds are released. The DPN represents the most advanced system studied so far under the VERT protocol achieving high conversion efficiencies for particles, NO, NO₂, CO, and hydrocarbons. However, we observed a trade-off between deNO(x) efficiency and secondary emissions. Therefore, it is important to adopt such DPN technology to specific application conditions to take advantage of reduced NO(x) and particle emissions while avoiding NH₃ and HNCO slip. PMID:23214996

  4. Bauxite-supported Transition Metal Oxides: Promising Low-temperature and SO2-tolerant Catalysts for Selective Catalytic Reduction of NOx

    PubMed Central

    Wang, Xiuyun; Wu, Wen; Chen, Zhilin; Wang, Ruihu

    2015-01-01

    In order to develop low-temperature (below 200 °C) and SO2-tolerant catalysts for selective catalytic reduction (SCR) of NOx, a series of cheap M/bauxite (M = Mn, Ni and Cu) catalysts were prepared using bauxite as a support. Their SCR performances are much superior to typical V2O5/TiO2, the addition of M into bauxite results in significant promotion of NOx removal efficiency, especially at low temperature. Among the catalysts, Cu/bauxite exhibits wide temperature window over 50–400 °C, strong resistance against SO2 and H2O as well as good regeneration ability in SCR of NOx. NOx conversion is more than 80% at 50–200 °C, and N2 selectivity is more than 98%. Cu/bauxite can serve as a promising catalyst in SCR of NOx. PMID:25988825

  5. Bauxite-supported Transition Metal Oxides: Promising Low-temperature and SO2-tolerant Catalysts for Selective Catalytic Reduction of NOx.

    PubMed

    Wang, Xiuyun; Wu, Wen; Chen, Zhilin; Wang, Ruihu

    2015-05-19

    In order to develop low-temperature (below 200 °C) and SO2-tolerant catalysts for selective catalytic reduction (SCR) of NOx, a series of cheap M/bauxite (M = Mn, Ni and Cu) catalysts were prepared using bauxite as a support. Their SCR performances are much superior to typical V2O5/TiO2, the addition of M into bauxite results in significant promotion of NOx removal efficiency, especially at low temperature. Among the catalysts, Cu/bauxite exhibits wide temperature window over 50-400 °C, strong resistance against SO2 and H2O as well as good regeneration ability in SCR of NOx. NOx conversion is more than 80% at 50-200 °C, and N2 selectivity is more than 98%. Cu/bauxite can serve as a promising catalyst in SCR of NOx.

  6. Effectiveness of Low Emission Zones: Large Scale Analysis of Changes in Environmental NO2, NO and NOx Concentrations in 17 German Cities

    PubMed Central

    Morfeld, Peter; Groneberg, David A.; Spallek, Michael F.

    2014-01-01

    Background Low Emission Zones (LEZs) are areas where the most polluting vehicles are restricted from entering. The effectiveness of LEZs to lower ambient exposures is under debate. This study focused on LEZs that restricted cars of Euro 1 standard without appropriate retrofitting systems from entering and estimated LEZ effects on NO2, NO, and NOx ( = NO2+NO). Methods Continuous half-hour and diffuse sampler 4-week average NO2, NO, and NOx concentrations measured inside and outside LEZs in 17 German cities of 6 federal states (2005–2009) were analysed as matched quadruplets (two pairs of simultaneously measured index values inside LEZ and reference values outside LEZ, one pair measured before and one after introducing LEZs with time differences that equal multiples of 364 days) by multiple linear and log-linear fixed-effects regression modelling (covariables: e.g., wind velocity, amount of precipitation, height of inversion base, school holidays, truck-free periods). Additionally, the continuous half-hour data was collapsed into 4-week averages and pooled with the diffuse sampler data to perform joint analysis. Results More than 3,000,000 quadruplets of continuous measurements (half-hour averages) were identified at 38 index and 45 reference stations. Pooling with diffuse sampler data from 15 index and 10 reference stations lead to more than 4,000 quadruplets for joint analyses of 4-week averages. Mean LEZ effects on NO2, NO, and NOx concentrations (reductions) were estimated to be at most −2 µg/m3 (or −4%). The 4-week averages of NO2 concentrations at index stations after LEZ introduction were 55 µg/m3 (median and mean values) or 82 µg/m3 (95th percentile). Conclusions This is the first study investigating comprehensively the effectiveness of LEZs to reduce NO2, NO, and NOx concentrations controlling for most relevant potential confounders. Our analyses indicate that there is a statistically significant, but rather small reduction of NO2, NO, and NOx

  7. Development of Optimal Catalyst Designs and Operating Strategies for Lean NOx Reduction in Coupled LNT-SCR Systems

    SciTech Connect

    Harold, Michael; Crocker, Mark; Balakotaiah, Vemuri; Luss, Dan; Choi, Jae-Soon; Dearth, Mark; McCabe, Bob; Theis, Joe

    2013-09-30

    Oxides of nitrogen in the form of nitric oxide (NO) and nitrogen dioxide (NO{sub 2}) commonly referred to as NO{sub x}, is one of the two chemical precursors that lead to ground-level ozone, a ubiquitous air pollutant in urban areas. A major source of NO{sub x} is generated by equipment and vehicles powered by diesel engines, which have a combustion exhaust that contains NO{sub x} in the presence of excess O{sub 2}. Catalytic abatement measures that are effective for gasoline-fueled engines such as the precious metal containing three-way catalytic converter (TWC) cannot be used to treat O2-laden exhaust containing NO{sub x}. Two catalytic technologies that have emerged as effective for NO{sub x} abatement are NO{sub x} storage and reduction (NSR) and selective catalytic reduction (SCR). NSR is similar to TWC but requires much larger quantities of expensive precious metals and sophisticated periodic switching operation, while SCR requires an on-board source of ammonia which serves as the chemical reductant of the NO{sub x}. The fact that NSR produces ammonia as a byproduct while SCR requires ammonia to work has led to interest in combining the two together to avoid the need for the cumbersome ammonia generation system. In this project a comprehensive study was carried out of the fundamental aspects and application feasibility of combined NSR/SCR. The project team, which included university, industry, and national lab researchers, investigated the kinetics and mechanistic features of the underlying chemistry in the lean NOx trap (LNT) wherein NSR was carried out, with particular focus on identifying the operating conditions such as temperature and catalytic properties which lead to the production of ammonia in the LNT. The performance features of SCR on both model and commercial catalysts focused on the synergy between the LNT and SCR converters in terms of utilizing the upstream-generated ammonia and alternative reductants such as propylene, representing the

  8. Apparatus and method for burning a lean, premixed fuel/air mixture with low NOx emission

    DOEpatents

    Kostiuk, Larry W.; Cheng, Robert K.

    1996-01-01

    An apparatus for enabling a burner to stably burn a lean fuel/air mixture. The burner directs the lean fuel/air mixture in a stream. The apparatus comprises an annular flame stabilizer; and a device for mounting the flame stabilizer in the fuel/air mixture stream. The burner may include a body having an internal bore, in which case, the annular flame stabilizer is shaped to conform to the cross-sectional shape of the bore, is spaced from the bore by a distance greater than about 0.5 mm, and the mounting device mounts the flame stabilizer in the bore. An apparatus for burning a gaseous fuel with low NOx emissions comprises a device for premixing air with the fuel to provide a lean fuel/air mixture; a nozzle having an internal bore through which the lean fuel/air mixture passes in a stream; and a flame stabilizer mounted in the stream of the lean fuel/air mixture. The flame stabilizer may be mounted in the internal bore, in which case, it is shaped and is spaced from the bore as just described. In a method of burning a lean fuel/air mixture, a lean fuel/air mixture is provided, and is directed in a stream; an annular eddy is created in the stream of the lean fuel/air mixture; and the lean fuel/air mixture is ignited at the eddy.

  9. Non-thermal plasma-assisted NOx reduction over Na-Y zeolites: The promotional effect of acid sites

    SciTech Connect

    Kwak, Ja Hun; Peden, Charles HF; Szanyi, Janos

    2006-06-01

    The effect of acid sites on the catalytic activities of a series of H+-modified Na-Y zeolites was investigated in the non-thermal plasma assisted NOx reduction reaction using a simulated diesel engine exhaust gas mixture. The acid sites were formed by NH4+ ion exchange and subsequent heat treatment of a NaY zeolite. The catalytic activities of these H+-modified NaY zeolites significantly increased with the number of acid sites. This NOx conversion increase was correlated with the decrease in the amount of unreacted NO2. The increase in the number of acid sites did not change the NO level, it stayed constant. Temperature programmed desorption following NO2 adsorption showed the appearance of a high temperature desorption peak at 453 K in addition to the main desorption feature of 343 K observed for the base Na-Y. The results of both the IR and TPD experiments revealed the formation of crotonaldehyde, resulting from condensation reaction of adsorbed acetaldehyde. Strong adsorptions of both NOx and hydrocarbon species are proposed to be responsible for the higher catalytic activity of H+-modified Na-Y zeolites in comparison to the base NaY material

  10. Regeneration of field-spent activated carbon catalysts for low-temperature selective catalytic reduction of NOx with NH3

    SciTech Connect

    Jeon, Jong Ki; Kim, Hyeonjoo; Park, Young-Kwon; Peden, Charles HF; Kim, Do Heui

    2011-10-15

    In the process of producing liquid crystal displays (LCD), the emitted NOx is removed over an activated carbon catalyst by using selective catalytic reduction (SCR) with NH3 at low temperature. However, the catalyst rapidly deactivates primarily due to the deposition of boron discharged from the process onto the catalyst. Therefore, this study is aimed at developing an optimal regeneration process to remove boron from field-spent carbon catalysts. The spent carbon catalysts were regenerated by washing with a surfactant followed by drying and calcination. The physicochemical properties before and after the regeneration were investigated by using elemental analysis, TG/DTG (thermogravimetric/differential thermogravimetric) analysis, N2 adsorption-desorption and NH3 TPD (temperature programmed desorption). Spent carbon catalysts demonstrated a drastic decrease in DeNOx activity mainly due to heavy deposition of boron. Boron was accumulated to depths of about 50 {mu}m inside the granule surface of the activated carbons, as evidenced by cross-sectional SEM-EDX analysis. However, catalyst activity and surface area were significantly recovered by removing boron in the regeneration process, and the highest NOx conversions were obtained after washing with a non-ionic surfactant in H2O at 70 C, followed by treatment with N2 at 550 C.

  11. Environmental effect of antioxidant additives on exhaust emission reduction in compression ignition engine fuelled with Annona methyl ester.

    PubMed

    Senthil, R; Silambarasan, R

    2015-01-01

    The aim of the present study is to analyse the effect of antioxidant l-ascorbic acid on engine performance and emissions of a diesel engine fuelled with methyl ester of Annona oil (MEAO). The antioxidant is mixed in various concentrations (100-400 mg) with MEAO. Result shows that the antioxidant additive mixture (MEAO+LA200) is effective in control of nitrogen oxides (NOx) and hydrocarbon (HC) emission of MEAO-fuelled engine without doing any engine modification. In this study by using MEAO, the NOx emission is reduced by about 23.38% at full load while compared with neat diesel fuel. Likewise there is a reduction in carbon monoxide, smoke, and HC by about 48%, 28.57% and 29.71% at full load condition compared with neat diesel fuel.

  12. Emissions of NOx, SO2, CO, and HCHO from commercial marine shipping during Texas Air Quality Study (TexAQS) 2006

    NASA Astrophysics Data System (ADS)

    Williams, E. J.; Lerner, B. M.; Murphy, P. C.; Herndon, S. C.; Zahniser, M. S.

    2009-11-01

    We report measurements of NOx, SO2, CO, and HCHO mass-based emission factors from more than 200 commercial vessel encounters in the Gulf of Mexico and the Houston-Galveston region of Texas during August and September, 2006. For underway ships, bulk freight carriers have the highest average NOx emissions at ˜87 g NOx (kg fuel)-1, followed by tanker ships at ˜79 g NOx (kg fuel)-1, while container carriers, passenger ships, and tugs all emit an average of about ˜60 g NOx (kg fuel)-1. Emission of NOx from stationary vessels was lower, except for container ships and tugs, and likely reflects use of medium-speed diesel engines. Overall, our mean NOx emission factors are 10-15% lower than published data. Average emission of SO2 was lower for passenger ships and tugs and tows (6-7 g SO2 (kg fuel)-1) than for larger cargo vessels (20-30 g SO2 (kg fuel)-1). Our data for large cargo ships in this region indicate an average residual fuel sulfur content of ˜1.4% which is a factor of two lower than the global average of 2.7%. Emission of CO was low for all categories (7-16 g CO (kg fuel)-1), although our mean overall CO emission factor is about 10% higher than published data. Emission of HCHO was less than 5% that of CO. Despite considerable variability, no functional relationships, such as emissions changes with engine speed or load, could be discerned. Comparison of emission factors from ships to those from other sources suggests ship emissions in this region cannot be ignored.

  13. Activity and hydrothermal stability of CeO₂-ZrO₂-WO₃ for the selective catalytic reduction of NOx with NH₃.

    PubMed

    Song, Zhongxian; Ning, Ping; Zhang, Qiulin; Li, Hao; Zhang, Jinhui; Wang, Yancai; Liu, Xin; Huang, Zhenzhen

    2016-04-01

    A series of CeO2-ZrO2-WO3 (CZW) catalysts prepared by a hydrothermal synthesis method showed excellent catalytic activity for selective catalytic reduction (SCR) of NO with NH3 over a wide temperature of 150-550°C. The effect of hydrothermal treatment of CZW catalysts on SCR activity was investigated in the presence of 10% H2O. The fresh catalyst showed above 90% NOx conversion at 201-459°C, which is applicable to diesel exhaust NOx purification (200-440°C). The SCR activity results indicated that hydrothermal aging decreased the SCR activity of CZW at low temperatures (below 300°C), while the activity was notably enhanced at high temperature (above 450°C). The aged CZW catalyst (hydrothermal aging at 700°C for 8 hr) showed almost 80% NOx conversion at 229-550°C, while the V2O5-WO3/TiO2 catalyst presented above 80% NOx conversion at 308-370°C. The effect of structural changes, acidity, and redox properties of CZW on the SCR activity was investigated. The results indicated that the excellent hydrothermal stability of CZW was mainly due to the CeO2-ZrO2 solid solution, amorphous WO3 phase and optimal acidity. In addition, the formation of WO3 clusters increased in size as the hydrothermal aging temperature increased, resulting in the collapse of structure, which could further affect the acidity and redox properties.

  14. Estimation of NOx emissions from vegetation fires based on the empirical relationship between satellite-derived tropospheric NO2 and fire radiative power

    NASA Astrophysics Data System (ADS)

    Schreier, S. F.; Richter, A.; Kaiser, J. W.; Burrows, J. P.

    2013-12-01

    Vegetation fires release large quantities of nitrogen oxides (NOx) into the atmosphere. These relatively short-lived reactive gases play key roles in atmospheric chemistry, air pollution, and climate. The traditional estimation of global NOx emissions from vegetation fires is based on the bottom-up approach by aggregating various local statistics. These statistics are based on parameters such as burned area, available fuel load, combustion completeness, and emission factors, which are derived from satellite measurements, laboratory experiments, and biogeochemical models. However, despite the progress achieved in deriving these parameters, there still exist large uncertainties for each parameter. The top-down estimation of NOx emissions from satellite measurements has the advantage of having a much higher spatio-temporal resolution. On the other hand, the conversion of the column number density into production rates of NOx and the partitioning between different NOx sources still remains challenging. In this study, we present a simple statistical approach for the estimation of production rates of NOx from fire by using the empirical relationship between satellite-derived tropospheric NO2 columns (from the GOME-2 instrument on board MetOp-A) and fire radiative power (from the MODIS instrument on board Terra). We show that the conversion of the column number density into production rates of NOx from fire is in good agreement with existing emission inventories. Therefore, we argue that this method allows for the adequate partitioning between biomass burning and other sources of NOx. The computation of Fire Emission Rates (FERs) of NOx for different land cover types indicates considerable differences among both the selected biomes and regions. The obtained FERs of NOx in combination with quantitative information about the diurnal cycle of the fire intensity are then applied for the estimation of NOx emissions from vegetation fires. A comparison of the achieved results

  15. 40 CFR 76.11 - Emissions averaging.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...) ACID RAIN NITROGEN OXIDES EMISSION REDUCTION PROGRAM § 76.11 Emissions averaging. (a) General... compliance with the Acid Rain emission limitation for NOX under the plan only if the following...

  16. 40 CFR 76.11 - Emissions averaging.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...) ACID RAIN NITROGEN OXIDES EMISSION REDUCTION PROGRAM § 76.11 Emissions averaging. (a) General... compliance with the Acid Rain emission limitation for NOX under the plan only if the following...

  17. 40 CFR 76.11 - Emissions averaging.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...) ACID RAIN NITROGEN OXIDES EMISSION REDUCTION PROGRAM § 76.11 Emissions averaging. (a) General... averaging plan is in compliance with the Acid Rain emission limitation for NOX under the plan only if...

  18. 40 CFR 76.11 - Emissions averaging.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...) ACID RAIN NITROGEN OXIDES EMISSION REDUCTION PROGRAM § 76.11 Emissions averaging. (a) General... averaging plan is in compliance with the Acid Rain emission limitation for NOX under the plan only if...

  19. 40 CFR 76.11 - Emissions averaging.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...) ACID RAIN NITROGEN OXIDES EMISSION REDUCTION PROGRAM § 76.11 Emissions averaging. (a) General... compliance with the Acid Rain emission limitation for NOX under the plan only if the following...

  20. WO3/CeO2-ZrO2, a promising catalyst for selective catalytic reduction (SCR) of NOx with NH3 in diesel exhaust.

    PubMed

    Li, Ye; Cheng, Hao; Li, Deyi; Qin, Yongsheng; Xie, Yuming; Wang, Shudong

    2008-03-28

    A WO3/CeO2-ZrO2 catalyst system was discovered for selective catalytic reduction of NOx with NH3; the catalyst (10 wt% WO3 loading) showed nearly 100% NOx conversion in a temperature range of 200-500 degrees C, at a space velocity of 90 000 h(-1) in a simulated diesel exhaust containing 550 ppm NOx (NO : NO2 feed ratio at 1.0), 10 vol% H2O and 10 vol% CO2; the catalyst also exhibited high temperature stability.

  1. Ammonia and NO/NOx measurement for DE-NOx applications

    SciTech Connect

    Kita, D.

    1996-10-01

    A number of critical environmental goals may be met by controlling nitrogen oxide (NOx) emissions from combustion sources. These goals include responding to 1990 Clean Air Act Amendment requirements, reduction of human exposure to harmful concentrations of nitric oxide (NO) and nitrogen dioxide (NO{sub 2}), acid deposition control, and urban smog abatement. Technologies utilizing either heterogeneous or homogeneous reactions of NOx with ammonia (NH{sub 3}) are considered major control options. Crucial to the use of such technologies is the continuous measurement of NO/NOx and NH{sub 3} in order to access (and control) performance criteria such as NOx conversion efficiency and NH{sub 3} emissions (NH{sub 3} SLIP) .This paper describes a continuous emission sonitoring system for NO, NO{sub 2}, and NH{sub 3} based upon NO chemiluminescence as well as presenting preliminary field data.

  2. Estimates of global biomass burning emissions for reactive greenhouse gases (CO, NMHCs, and NOx) and CO2

    NASA Astrophysics Data System (ADS)

    Jain, Atul K.; Tao, Zhining; Yang, Xiaojuan; Gillespie, Conor

    2006-03-01

    Open fire biomass burning and domestic biofuel burning (e.g., cooking, heating, and charcoal making) algorithms have been incorporated into a terrestrial ecosystem model to estimate CO2 and key reactive GHGs (CO, NOx, and NMHCs) emissions for the year 2000. The emissions are calculated over the globe at a 0.5° × 0.5° spatial resolution using tree density imagery, and two separate sets of data each for global area burned and land clearing for croplands, along with biofuel consumption rate data. The estimated global and annual total dry matter (DM) burned due to open fire biomass burning ranges between 5221 and 7346 Tg DM/yr, whereas the resultant emissions ranges are 6564-9093 Tg CO2/yr, 438-568 Tg CO/yr, 11-16 Tg NOx/yr (as NO), and 29-40 Tg NMHCs/yr. The results indicate that land use changes for cropland is one of the major sources of biomass burning, which amounts to 25-27% (CO2), 25 -28% (CO), 20-23% (NO), and 28-30% (NMHCs) of the total open fire biomass burning emissions of these gases. Estimated DM burned associated with domestic biofuel burning is 3,114 Tg DM/yr, and resultant emissions are 4825 Tg CO2/yr, 243 Tg CO/yr, 3 Tg NOx/yr, and 23 Tg NMHCs/yr. Total emissions from biomass burning are highest in tropical regions (Asia, America, and Africa), where we identify important contributions from primary forest cutting for croplands and domestic biofuel burning.

  3. Ammonia-Free NOx Control System

    SciTech Connect

    Song Wu; Zhen Fan; Richard G. Herman

    2004-12-31

    Research is being conducted under United States Department of Energy (DOE) Contract DEFC26-03NT41865 to develop a new technology to achieve very low levels of NOx emissions from pulverized coal fired boiler systems by employing a novel system level integration between the PC combustion process and the catalytic NOx reduction with CO present in the combustion flue gas. The combustor design and operating conditions will be optimized to achieve atypical flue gas conditions. This approach will not only suppress NOx generation during combustion but also further reduce NOx over a downstream catalytic reactor that does not require addition of an external reductant, such as ammonia. This report describes the work performed during the October 1 to December 30, 2004 time period.

  4. Ammonia-Free NOx Control System

    SciTech Connect

    Song Wu; Zhen Fan; Andrew H. Seltzer; Richard G. Herman

    2004-09-30

    Research is being conducted under United States Department of Energy (DOE) Contract DEFC26-03NT41865 to develop a new technology to achieve very low levels of NOx emissions from pulverized coal fired boiler systems by employing a novel system level integration between the PC combustion process and the catalytic NOx reduction with CO present in the combustion flue gas. The combustor design and operating conditions will be optimized to achieve atypical flue gas conditions. This approach will not only suppress NOx generation during combustion but also further reduce NOx over a downstream catalytic reactor that does not require addition of an external reductant, such as ammonia. This report describes the work performed during the July 1 to September 30, 2004 time period.

  5. Ammonia-Free NOx Control System

    SciTech Connect

    Zhen Fan; Song Wu; Richard G. Herman

    2004-06-30

    Research is being conducted under United States Department of Energy (DOE) Contract DEFC26-03NT41865 to develop a new technology to achieve very low levels of NOx emissions from pulverized coal fired boiler systems by employing a novel system level integration between the PC combustion process and the catalytic NOx reduction with CO present in the combustion flue gas. The combustor design and operating conditions will be optimized to achieve atypical flue gas conditions. This approach will not only suppress NOx generation during combustion but also further reduce NOx over a downstream catalytic reactor that does not require addition of an external reductant, such as ammonia. This report describes the work performed during the April 1 to June 30, 2004 time period.

  6. Ammonia-Free NOx Control System

    SciTech Connect

    S. Wu; Z. Fan; R. Herman

    2004-03-31

    Research is being conducted under United States Department of Energy (DOE) Contract DEFC26-03NT41865 to develop a new technology to achieve very low levels of NOx emissions from pulverized coal fired boiler systems by employing a novel system level integration between the PC combustion process and the catalytic NOx reduction with CO present in the combustion flue gas. The combustor design and operating conditions will be optimized to achieve atypical flue gas conditions. This approach will not only suppress NOx generation during combustion but also further reduce NOx over a downstream catalytic reactor that does not require addition of an external reductant, such as ammonia. This report describes the work performed during the January 1 to March 31, 2004 time period.

  7. Integrated Dry NOx/SO2 Emissions Control System, A DOE Assessment

    SciTech Connect

    National Energy Technology Laboratory

    2001-10-01

    The goal of the U.S. Department of Energy's (DOE) Clean Coal Technology (CCT) Program is to furnish the energy marketplace with a number of advanced, more efficient, and environmentally responsible coal utilization technologies through demonstration projects. These projects seek to establish the commercial feasibility of the most promising advanced coal technologies that have developed beyond the proof-of-concept stage. This document serves as a DOE post-project assessment (PPA) of a project selected in CCT Round III, the Integrated Dry NO{sub x}/SO{sub 2} Emissions Control System (IDECS), as described in a Report to Congress (U.S. Department of Energy 1991). The desire to reduce emissions of nitrogen oxides (NO, nitric oxide, and NO{sub 2}, nitrogen dioxide, collectively referred to as NO{sub x}) and sulfur dioxide (SO{sub 2}) by up to 70 percent at a minimum capital expenditure, while limiting waste production to dry solids that can be handled by conventional ash-removal equipment, prompted Public Service Company of Colorado (PSCC) to submit the proposal for the IDECS project. In March 1991, PSCC entered into a cooperative agreement with DOE to conduct the study. The project was sited at PSCC's Arapahoe Steam Electric Generating Station in Denver, Colorado. The purpose of this CCT project was to demonstrate the reduction of NO{sub x} and SO{sub 2} emissions by installing a combination of existing and emerging technologies, which were expected to work synergistically to reduce emissions. The technologies were low-NO{sub x} burners (LNBS), overfire air (OFA), and selective noncatalytic reduction (SNCR) for NO{sub x} reduction; and dry sorbent injection (DSI), both with and without flue-gas humidification (FGH), for SO{sub 2} reduction. DOE provided 50 percent of the total project funding of $26.2 million.

  8. MODELING ASSESSMENT OF THE IMPACT OF NITROGEN OXIDES EMISSION REDUCTIONS ON OZONE AIR QUALITY IN THE EASTERN UNITED STATES: OFFSETTING INCREASES IN ENERGY USE

    EPA Science Inventory

    The objective of this study is to examine changes in ambient ozone concentrations estimated by a photochemical air quality model in response to the NOx emission reductions imposed on the utility sector. To accomplish this task, CMAQ air quality model simulations were performe...

  9. Slower ozone production in Houston, Texas following emission reductions: evidence from Texas Air Quality Studies in 2000 and 2006

    NASA Astrophysics Data System (ADS)

    Zhou, W.; Cohan, D. S.; Henderson, B. H.

    2014-03-01

    Airborne measurements from two Texas Air Quality Study (TexAQS) field campaigns have been used to investigate changes of ozone production in Houston, Texas, from 2000 to 2006, a period of major emission reduction measures for petrochemical and other sources. Simultaneous declines in nitrogen oxides (NOx = NO + NO2) and highly reactive volatile organic compounds (HRVOCs) were observed between the two periods. We simulate HOx (OH and HO2) and organic radicals with a box model, the Dynamically Simple Model of Atmospheric Chemical Complexity, constrained by available airborne observations. Parameters such as total radical production, total OH reactivity of VOCs and ozone production rate (OPR) are computed to characterize the change of ozone production between 2000 and 2006 in the Houston area. The reduction in HRVOCs led to a decline in total radical production by 20-50%. Ozone production rates in the Houston area declined by 40-50% from 2000 to 2006, to which the reduction in NOx and HRVOCs made large contributions. Despite the significant decline in OPR, ozone production efficiency held steady, and VOC-sensitive conditions dominated during times of most rapid ozone formation, while the slow ozone formation continued to be NOx-limited. Our results highlight the importance of a balanced approach of ongoing HRVOC controls with NOx controls to further reduce O3 levels in the Houston area.

  10. Modeling the Effects of VOC and NOx Emission Sources on Ozone Formation in Houston during the TexAQS 2000 Field Campaign

    SciTech Connect

    Jiang, Guangfeng; Fast, Jerome D.

    2004-09-01

    A meteorological and chemical modeling system is used to determine the effect of ethene and propene point source emission rates on the magnitude and distribution of ozone in the vicinity of Houston. The model performance is evaluated using surface and airborne meteorological and chemical measurements made as part of the 2000 Texas Air Quality Study. A simulation that employed the reported mobile, area, biogenic, and point source emissions produced ozone mixing ratios as high as 120 ppb and distributions of nitrogen oxides that were similar to measurements at most locations, but the model underestimated ozone mixing ratios greater than 140 ppb that were located just downwind of petrochemical facilities. When the point source emission rates of ethene and propene were increased by a factor of 10, the simulated peak ozone levels were in better agreement with surface, aircraft, and lidar observations. The magnitude of the simulated ethene and olefin concentrations were in better agreement with canister samples aloft as well; however, there was still a large amount of scatter in the results. While the highest ozone mixing ratios were produced just downwind of large point source emissions of VOCs, sensitivity simulations also showed that reductions in anthropogenic emissions of NOx would be needed to reduce ozone mixing ratios over a larger area.

  11. NOx reduction in combustion with concentrated coal streams and oxygen injection

    DOEpatents

    Kobayashi, Hisashi; Bool, III, Lawrence E.; Snyder, William J.

    2004-03-02

    NOx formation in the combustion of solid hydrocarbonaceous fuel such as coal is reduced by obtaining, from the incoming feed stream of fuel solids and air, a stream having a ratio of fuel solids to air that is higher than that of the feed steam, and injecting the thus obtained stream and a small amount of oxygen to a burner where the fuel solids are combusted.

  12. Detection from space of a reduction in anthropogenic emissions of nitrogen oxides during the Chinese economic downturn

    NASA Astrophysics Data System (ADS)

    Lin, J.-T.; McElroy, M. B.

    2011-08-01

    Rapid economic and industrial development in China and relatively weak emission controls have resulted in significant increases in emissions of nitrogen oxides (NOx) in recent years, with the exception of late 2008 to mid 2009 when the economic downturn led to emission reductions detectable from space. Here vertical column densities (VCDs) of tropospheric NO2 retrieved from satellite observations by SCIAMACHY, GOME-2 and OMI (both by KNMI and by NASA) are used to evaluate changes in emissions of NOx from October 2004 to February 2010 identifying impacts of the economic downturn. Data over polluted regions of Northern East China suggest an increase of 27-33 % in 12-month mean VCD of NO2 prior to the downturn, consistent with an increase of 49 % in thermal power generation (TPG) reflecting the economic growth. More detailed analysis is used to quantify changes in emissions of NOx in January over the period 2005-2010 when the effect of the downturn was most evident. The GEOS-Chem model is employed to evaluate the effect of changes in chemistry and meteorology on VCD of NO2. This analysis indicates that emissions decreased by 20 % from January 2008 to January 2009, close to the reduction of 18 % in TPG that occurred over the same interval. A combination of three independent approaches indicates that the economic downturn was responsible for a reduction in emissions by 9-11 % in January 2009 with an additional decrease of 10 % attributed to the slow-down in industrial activity associated with the coincident celebration of the Chinese New Year; errors in the estimate are most likely less than 3.4 %.

  13. Detection from space of a reduction in anthropogenic emissions of nitrogen oxides during the Chinese economic downturn

    NASA Astrophysics Data System (ADS)

    Lin, J.-T.; McElroy, M. B.

    2011-01-01

    Rapid economic and industrial development in China and relatively weak emission controls have resulted in significant increases in emissions of nitrogen oxides (NOx) in recent years, with the exception of late 2008 to mid 2009 when the economic downturn led to emission reductions detectable from space. Here vertical column densities (VCDs) of tropospheric NO2 retrieved from satellite observations by SCIAMACHY, GOME-2 and OMI (both by KNMI and by NASA) are used to evaluate changes in emissions of NOx from October 2004 to February 2010 identifying impacts of the economic downturn. Data over polluted regions of Northern East China suggest an increase of 27-33% in annual mean VCD of NO2 prior to the downturn, consistent with an increase of 49% in thermal power generation (TPG) reflecting the economic growth. More detailed analysis is used to quantify changes in emissions of NOx in January over the period 2005-2010 when the effect of the downturn was most evident. The GEOS-Chem model is employed to evaluate the effect of changes in chemistry and meteorology on VCD of NO2. This analysis indicates that emissions decreased by 20% from January 2008 to January 2009, close to the reduction of 18% in TPG that occurred over the same interval. A combination of three relatively independent approaches indicates that the economic downturn was responsible for a~reduction in emissions by 9-11% in January 2009 with an additional decrease of 10% attributed to the slow-down in industrial activity associated with the coincident celebration of the Chinese New Year.

  14. An optimization study on the control of NOx and particulate emissions from diesel engines

    SciTech Connect

    Larsen, C.; Oey, F.; Levendis, Y.A.

    1996-09-01

    This is an optimization study on the use of filtered exhaust gas recirculation (EGR) to reduce the NO emissions of diesel engines. Control of the particulate emissions and provisions for filtered EGR were achieved by an Aerodynamically Regenerated Trap (ART) with collection efficiencies in the order of 99%. The amount of EGR was regulated to provide for substantial NO reduction, without unacceptably decreasing the thermal efficiency of the engine or increasing the CO emissions. EGR regulation was accomplished by monitoring the injection pump setting which was correlated to the fuel flow rate, the speed of the engine, the amount of EGR flow, and the ambient air temperature. Through these parameters, the mixture strength expressed as the equivalence ratio {phi} was calculated and related to the power output of the engine. Thus, a map of engine performance parameters was generated and related to measured NO and CO emissions. A series of road tests showed that EGR most effectively reduces NO emissions at high {phi}`s (by a factor of two at 20% EGR) which, however, is accompanied by an increase in CO emissions by a factor of two, and a penalty in fuel economy by 8%. Benefits and losses can be optimized by automatically varying the level of EGR, using feedback from the aforementioned engine parameters. An algorithm was developed to govern the electrically controlled EGR valve and tests showed that the NO levels decreased by 30%, while the CO increased by 30%, showing no penalty in fuel economy. The resulting specific NO and CO emissions were well within the current US EPA standards.

  15. Source apportionment and health effect of NOx over the Pearl River Delta region in southern China.

    PubMed

    Lu, Xingcheng; Yao, Teng; Li, Ying; Fung, Jimmy C H; Lau, Alexis K H

    2016-05-01

    As one of the most notorious atmospheric pollutants, NOx not only promotes the formation of ozone but also has adverse health effects on humans. It is therefore of great importance to study the sources of NOx and its effects on human health. The Comprehensive Air Quality Model (CAMx) modeling system and ozone source apportionment technology (OSAT) were used to study the contribution of NOx from different emission sources over southern China. The results indicate that heavy duty diesel vehicles (HDDVs) and industrial point sources are the two major local NOx sources, accounting for 30.8% and 18.5% of local NOx sources, respectively. In Hong Kong, marine emissions contributed around 43.4% of local NOx in 2011. Regional transport is another important source of this pollutant, especially in February and November, and it can contribute over 30% of ambient NOx on average. Power plant point emission is an significant regional source in Zhuhai, Zhongshan and Foshan. The total emission sources are estimated to cause 2119 (0-4405) respiratory deaths and 991 (0-2281) lung cancer deaths due to long-term exposure to NOx in the Pearl River Delta region. Our results suggest that local governments should combine their efforts and vigorously promote further reduction of NOx emissions, especially for those sources that make a substantial contribution to NOx emissions and affect human health: HDDV, LDGV, industrial point sources and marine sources.

  16. Source apportionment and health effect of NOx over the Pearl River Delta region in southern China.

    PubMed

    Lu, Xingcheng; Yao, Teng; Li, Ying; Fung, Jimmy C H; Lau, Alexis K H

    2016-05-01

    As one of the most notorious atmospheric pollutants, NOx not only promotes the formation of ozone but also has adverse health effects on humans. It is therefore of great importance to study the sources of NOx and its effects on human health. The Comprehensive Air Quality Model (CAMx) modeling system and ozone source apportionment technology (OSAT) were used to study the contribution of NOx from different emission sources over southern China. The results indicate that heavy duty diesel vehicles (HDDVs) and industrial point sources are the two major local NOx sources, accounting for 30.8% and 18.5% of local NOx sources, respectively. In Hong Kong, marine emissions contributed around 43.4% of local NOx in 2011. Regional transport is another important source of this pollutant, especially in February and November, and it can contribute over 30% of ambient NOx on average. Power plant point emission is an significant regional source in Zhuhai, Zhongshan and Foshan. The total emission sources are estimated to cause 2119 (0-4405) respiratory deaths and 991 (0-2281) lung cancer deaths due to long-term exposure to NOx in the Pearl River Delta region. Our results suggest that local governments should combine their efforts and vigorously promote further reduction of NOx emissions, especially for those sources that make a substantial contribution to NOx emissions and affect human health: HDDV, LDGV, industrial point sources and marine sources. PMID:26845361

  17. Reduction of chlorofluorocarbon emissions from refrigeration systems

    SciTech Connect

    Cordova, A.; Kennicott, M.A.

    1992-09-01

    Recently enacted State and Federal legislation, (The Clean Air Act and Colorado Senate Bill 77), and the implementation of regulations for each, forbid the intentional release of ozone depleting chlorofluorocarbons(CFCs) from refrigeration and air conditioning systems to the atmosphere. In addition, an international agreement (The Montreal Protocol), calls for CFC manufacturing reductions, which began in 1991, and eventual discontinuation. The declining supply and resultant escalating costs of CFCs are additional driving forces toward conservation and reuse of present refrigerant resources. Rocky Flats Plant (RFP) currently has an estimated 42,000 pounds of CFCs in refrigeration and air conditioning systems. The purpose of this paper is to discuss steps being taken at RFP toward the abatement of CFC releases. The main thrust of our efforts is the use of a refrigerant management system, used to recover and recycle our current CFC stock. Additional methods of further reducing CFC emissions will also be discussed. These include the installation of state-of-the-art oil filtration systems on major chiller units, installation of spring-loaded pressure relief valves and the retrofitting of major chiller units to accept less harmful, alternative refrigerants.

  18. Effect of manufacturing methods of AgCl/Al2O3 catalyst on selective catalytic reduction of NO(x).

    PubMed

    Kishida, Satoshi; Ju, Dong-Ying; Aritani, Hirofumi

    2011-01-01

    The AgCl/Al2O3 catalyst has potential for use in the selective catalytic reduction (SCR) of NO(x). A compound hydrocarbon, following oxygenation is used as a type of reducing agent. In this experiment, the AgCl/Al2O3 catalyst was produced by four different methods, and the differences among their reduction catalysis of NO(x) were compared. Ethanol was used as a type of reducing agent. X-ray diffraction analysis was performed to study the crystalline structure and scanning electron microscope and transmission electron microscope (TEM) were applied to determine the microindentation. The results indicated that, in the range of 350-400 degrees C, there was no significant difference on the NO(x) reduction rate; however, there was dispersion at high and low temperature ranges. The size of the AgCl particles was about 20-100 nm.

  19. Effects of Particle Filters and Selective Catalytic Reduction on Heavy-Duty Diesel Drayage Truck Emissions at the Port of Oakland.

    PubMed

    Preble, Chelsea V; Dallmann, Timothy R; Kreisberg, Nathan M; Hering, Susanne V; Harley, Robert A; Kirchstetter, Thomas W

    2015-07-21

    Effects of fleet modernization and use of diesel particle filters (DPF) and selective catalytic reduction (SCR) on heavy-duty diesel truck emissions were studied at the Port of Oakland in California. Nitrogen oxides (NOx), black carbon (BC), particle number (PN), and size distributions were measured in the exhaust plumes of ∼1400 drayage trucks. Average NOx, BC, and PN emission factors for newer engines (2010-2013 model years) equipped with both DPF and SCR were 69 ± 15%, 92 ± 32%, and 66 ± 35% lower, respectively, than 2004-2006 engines without these technologies. Intentional oxidation of NO to NO2 for DPF regeneration increased tailpipe NO2 emissions, especially from older (1994-2006) engines with retrofit DPFs. Increased deployment of advanced controls has further skewed emission factor distributions; a small number of trucks emit a disproportionately large fraction of total BC and NOx. The fraction of DPF-equipped drayage trucks increased from 2 to 99% and the median engine age decreased from 11 to 6 years between 2009 and 2013. Over this period, fleet-average BC and NOx emission factors decreased by 76 ± 22% and 53 ± 8%, respectively. Emission changes occurred rapidly compared to what would have been observed due to natural (i.e., unforced) turnover of the Port truck fleet. These results provide a preview of more widespread emission changes expected statewide and nationally in the coming years. PMID:26083075

  20. Effects of Particle Filters and Selective Catalytic Reduction on Heavy-Duty Diesel Drayage Truck Emissions at the Port of Oakland.

    PubMed

    Preble, Chelsea V; Dallmann, Timothy R; Kreisberg, Nathan M; Hering, Susanne V; Harley, Robert A; Kirchstetter, Thomas W

    2015-07-21

    Effects of fleet modernization and use of diesel particle filters (DPF) and selective catalytic reduction (SCR) on heavy-duty diesel truck emissions were studied at the Port of Oakland in California. Nitrogen oxides (NOx), black carbon (BC), particle number (PN), and size distributions were measured in the exhaust plumes of ∼1400 drayage trucks. Average NOx, BC, and PN emission factors for newer engines (2010-2013 model years) equipped with both DPF and SCR were 69 ± 15%, 92 ± 32%, and 66 ± 35% lower, respectively, than 2004-2006 engines without these technologies. Intentional oxidation of NO to NO2 for DPF regeneration increased tailpipe NO2 emissions, especially from older (1994-2006) engines with retrofit DPFs. Increased deployment of advanced controls has further skewed emission factor distributions; a small number of trucks emit a disproportionately large fraction of total BC and NOx. The fraction of DPF-equipped drayage trucks increased from 2 to 99% and the median engine age decreased from 11 to 6 years between 2009 and 2013. Over this period, fleet-average BC and NOx emission factors decreased by 76 ± 22% and 53 ± 8%, respectively. Emission changes occurred rapidly compared to what would have been observed due to natural (i.e., unforced) turnover of the Port truck fleet. These results provide a preview of more widespread emission changes expected statewide and nationally in the coming years.