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. Cost-effective reduction of NOx emissions from electricity generation

    SciTech Connect

    Burtraw, D.; Palmer, K.; Bharvirkar, R.; Paul, A.

    2001-07-15

    This paper analyzes the benefits and costs of policies to reduce NOx emissions from electricity generation in the United States. Because emissions of NOx contribute to the high concentration of atmospheric ozone in the eastern states associated with health hazards, the US Environmental Protection Agency (EPA) has called on eastern states to formulate state implementation plans (SIPs) for reducing NOx emissions. The analysis considers three NOx reduction scenarios: a summer seasonal cap in the eastern states covered by EPA's NOx SIP call, an annual cap in the same SIP Call region, and a national annual cap. All scenarios allow for emissions trading. Although EPA's current policy is to implement a seasonal cap in the SIP Call region, this analysis indicates that an annual cap in the SIP Call region would yield about 400 million dollars more in net benefits (benefits less costs) than would a seasonal policy, based on particulate-related health effects only. An annual cap in the SIP Call region is also the policy that is most likely to achieve benefits in excess of costs. Consideration of omissions from this accounting, including the potential benefits from reductions in ozone concentrations, strengthens the finding that an annual program offers greater net benefits than does a seasonal program. 22 refs., 1 fig., 10 tabs.

  4. Reconciling NOx emissions reductions and ozone trends in ...

    EPA Pesticide Factsheets

    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 NO

  5. 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

  6. 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

  7. 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

  8. Observations and Modeling of US Power Plant NOx Emission Reductions and Their Impact on Air Quality

    NASA Astrophysics Data System (ADS)

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

    2007-12-01

    Nitrogen oxide (NOx) emissions resulting from fossil fuel combustion lead to unhealthy levels of near-surface ozone (O3). One of the largest US sources, electric power generation, represented about 25% of US anthropogenic NOx emissions prior to the recent implementation of pollution controls by utility companies. Continuous emission monitoring data demonstrate that overall US power plant NOx emissions decreased about 50% during the summer ozone season since the late 1990's. Space-based instruments observed declining regional NOx levels between 1999 and 2005 in response to these emission reductions. Satellite-retrieved summertime nitrogen dioxide (NO2) columns and bottom-up emission estimates show larger decreases in the Ohio River Valley, where power plants dominate NOx emissions, than in the northeast US urban corridor. Model simulations predict lower O3 across much of the eastern US in response to these emission reductions.

  9. 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.

  10. Summary of NOx Emissions Reduction from Biomass Cofiring

    SciTech Connect

    Dayton, D.

    2002-05-01

    NOx emissions from commercial- and pilot-scale biomass/coal cofiring demonstrations are reduced as the percentage of energy supplied to the boiler by the biomass fuel is increased. This report attempts to provide a summary of the NO{sub x} emissions measured during recent biomass/coal cofiring demonstrations. These demonstrations were carried out at the commercial and pilot-scales. Commercial-scale tests were conducted in a variety of pulverized fuel boiler types including wall-fired, T-fired, and cyclone furnaces. Biomass input ranged up to 20% on a mass basis and 10% on an energy basis.

  11. 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

  12. Modeling and optimization of coal and coal-water slurry reburning for NOx emissions reduction

    SciTech Connect

    Zarnescu, V.; Pisupati, S.V.

    1999-07-01

    The performance of coal and coal-water slurry as reburn fuels in a pilot scale 0.5 MM Btu/hr Down-fired combustor (DFC) was predicted using numerical simulations and compared with measurements. Previous low NOx level burner modeling results have been used together with the whole-furnace design approach. Flow and combustion parameters, fuels and firing configurations and reburning parameters are studied and optimized for maximum NOx reduction performance. Comparisons are made between coal and coal-water slurry and biomass as reburn fuels. A sensitivity analysis was conducted in order to analyze the variation of predictions with respect to model parameters. Modeling results show that improved mixing, burner aerodynamics and flame attachment can contribute significantly to lowering the primary zone NOx levels. This fact, coupled with optimized reburning parameters can result in important NOx emissions reduction. Different scenarios are discussed and recommendations are made for maximum NOx reduction efficiency.

  13. 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

    2013-05-07

    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.

  14. 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.

  15. 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...

  16. Atmospheric pollution reduction effect and regional predicament: An empirical analysis based on the Chinese provincial NOx emissions.

    PubMed

    Ding, Lei; Liu, Chao; Chen, Kunlun; Huang, Yalin; Diao, Beidi

    2017-03-09

    Atmospheric pollution emissions have become a matter of public concern in recent years. However, most of the existing researches on NOx pollution are from the natural science and technology perspective, few studies have been conducted from an economic point, and regional differences have not been given adequate attention. This paper adopts provincial panel data from 2006 to 2013 and the LMDI model to analyze the key driving factors and regional dilemmas of NOx emissions. The results show that significant regional disparities still exit on NOx emissions and its reduction effect 27 provinces didn't accomplish their corresponding reduction targets. Economic development factor is the dominating driving factor of NOx emissions during the study period, while energy efficiency and technology improvement factors offset total NOx emissions in the majority of provinces. In addition, the industrial structure factor plays a more significant role in reducing the NOx emissions after 2011. Therefore, the government should consider all these factors as well as regional heterogeneity in developing appropriate pollution mitigating policies. It's necessary to change NOx emissions control attitude from original key areas control to divided-zone control, not only attaches great importance to the reduction of the original key areas, but also emphasizes the new potential hotspots with high NOx emissions.

  17. 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.

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

    PubMed

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

    2015-04-07

    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.

  19. Satellite-observed U.S. power plant NOx emission reductions and their impact on air quality

    NASA Astrophysics Data System (ADS)

    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.

    2006-11-01

    Nitrogen oxide (NOx) emissions resulting from fossil fuel combustion lead to unhealthy levels of near-surface ozone (O3). 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 (NO2) 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 O3 across much of the eastern U.S. in response to these emission reductions.

  20. 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

    2012-06-05

    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.

  1. Satellite-Observed US Power Plant NOx Emission Reductions and Their Impact on Air Quality

    NASA Astrophysics Data System (ADS)

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

    2005-05-01

    Nitrogen oxide (NOx) emissions resulting from fossil fuel combustion lead to unhealthy levels of near-surface ozone (O3). O3 exceedances in the northeast US have been associated with NOx emissions from point sources, especially coal-burning power plants. As a result, numerous programs to control point source NOx emissions in the eastern US have been implemented over the past decade. Here we assess the change of regional NOx emissions in the eastern US by comparing nitrogen dioxide (NO2) columns derived from the satellite instruments with three-dimensional regional scale chemical transport model results that include the estimated NOx emission changes. SCIAMACHY measurements are used in comparisons with WRF-Chem model simulations for 2004 because of their availability and similar horizontal resolution to the model simulations. However, to get the long term evolution of NO2 columns between 1997 and 2005, both GOME and SCIAMACHY data are utilized. Satellite observations clearly detect both year-to-year and summertime NO2 column decreases in regions impacted by power plants that have implemented NOx controls over the past decade. In the Ohio River Valley, where power plants dominate NOx emission, satellite-retrieved summertime NO2 columns and bottom-up emission estimates show larger decreases than in the northeast US urban corridor.

  2. Satellite-Observed US Power Plant NOx Emission Reductions and Their Impact on Air Quality

    NASA Astrophysics Data System (ADS)

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

    2006-12-01

    Nitrogen oxide (NOx) emissions resulting from fossil fuel combustion lead to unhealthy levels of near-surface ozone (O3). O3 exceedances in the northeast US have been associated with NOx emissions from point sources, especially coal-burning power plants. As a result, numerous programs to control point source NOx emissions in the eastern US have been implemented over the past decade. Here we assess the change of regional NOx emissions in the eastern US by comparing nitrogen dioxide (NO2) columns derived from the satellite instruments with three-dimensional regional scale chemical transport model results that include the estimated NOx emission changes. SCIAMACHY measurements are used in comparisons with WRF-Chem model simulations for 2004 because of their availability and similar horizontal resolution to the model simulations. However, to get the long term evolution of NO2 columns between 1997 and 2005, both GOME and SCIAMACHY data are utilized. Satellite observations clearly detect both year-to-year and summertime NO2 column decreases in regions impacted by power plants that have implemented NOx controls over the past decade. In the Ohio River Valley, where power plants dominate NOx emission, satellite-retrieved summertime NO2 columns and bottom-up emission estimates show larger decreases than in the northeast US urban corridor.

  3. 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

  4. 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.

  5. Reduction in NO(x) emission trends over China: regional and seasonal variations.

    PubMed

    Gu, Dasa; Wang, Yuhang; Smeltzer, Charles; Liu, Zhen

    2013-11-19

    We analyzed satellite observations of nitrogen dioxide (NO2) columns by the Ozone Monitoring Instrument (OMI) over China from 2005 to 2010 in order to estimate the top-down anthropogenic nitrogen oxides (NOx) emission trends. Since NOx emissions were affected by the economic slowdown in 2009, we removed one year of abnormal data in the analysis. The estimated average emission trend is 4.01 ± 1.39% yr(-1), which is slower than the trend of 5.8-10.8% yr(-1) reported for previous years. We find large regional, seasonal, and urban-rural variations in emission trends. The average NOx emission trend of 3.47 ± 1.07% yr(-1) in warm season (June-September) is less than the trend of 5.03 ± 1.92% yr(-1) in cool season (October-May). The regional annual emission trends decrease from 4.76 ± 1.61% yr(-1) in North China Plain to 3.11 ± 0.98% yr(-1) in Yangtze River Delta and further down to -4.39 ± 1.81% yr(-1) in Pearl River Delta. The annual emission trends of the four largest megacities, Shanghai, Beijing, Guangzhou, and Shenzhen are -0.76 ± 0.29%, 0.69 ± 0.27%, -4.46 ± 1.22%, and -7.18 ± 2.88% yr(-1), considerably lower than the regional averages or surrounding rural regions. These results appear to suggest that a number of factors, including emission control measures of thermal power plants, increased hydro-power usage, vehicle emission regulations, and closure or migration of high-emission industries, have significantly reduced or even reversed the increasing trend of NOx emissions in more economically developed megacities and southern coastal regions, but their effects are not as significant in other major cities or less economically developed regions.

  6. 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.

  7. 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

  8. Emission reduction of NOx and CO by optimization of the automatic control system in a coal-fired stoker boiler

    SciTech Connect

    Schnelle, K.B.; Laungphairojana, A.; Debelak, K.A.

    2006-07-15

    To date research on NO, and CO emission reduction in stoker-fired boilers has been devoted to combustion modification to the overfire air, diverting air to a selected set of burners, using modified low-NOx, burners, using flue gas recirculation or flue gas treatment with specially controlled catalyst and additives. This study introduces a concept that focuses on the dynamics of the boiler and the automatic control system. The objective of this study was to reduce the NO and CO emissions by restructuring the automatic control system and then tuning the control system with parameters that have been optimized with emission reduction as the objective. Dynamic data were obtained from a step-input test of either the underfire air or the overfire air. These data were used to model the boiler with a transfer function describing the emissions. The analyzer dynamic response was included in the overall model. The control parameters were determined from this overall emissions transfer function by mathematical optimization. These control parameters constituted the initial values in the automatic control system used for the final tests in the boiler. Additional adjustments to reduce the emissions were carried out during boiler operation. A low controller gain and a fast reset time were found to be the most suitable setting for the control system. The NO emissions controlled by the overfire air and CO emissions controlled by the underfire air produced the best results.

  9. 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

  10. 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

  11. Reconciling NOx emissions reductions and ozone trends in the U.S., 2002–2006

    EPA Science Inventory

    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 me...

  12. Antioxidant (A-tocopherol acetate) effect on oxidation stability and NOx emission reduction in methyl ester of Annona oil operated diesel engine

    NASA Astrophysics Data System (ADS)

    Senthil, R.; Silambarasan, R.; Pranesh, G.

    2016-11-01

    There is a major drawback while using biodiesel as a alternate fuel for compression ignition diesel engine due to lower heating value, higher viscosity, higher density and higher oxides of nitrogen emission. To minimize these drawbacks, fuel additives can contribute towards engine performance and exhaust emission reduction either directly or indirectly. In this current work, the test was conducted to investigate the effect of antioxidant additive (A-tocopherol acetate) on oxidation stability and NOx emission in a of Annona methyl ester oil (MEAO) fueled diesel engine. The A-tocopherol acetate is mixed in different concentrations such as 0.01, 0.02, 0.03 and 0.04% with 100% by vol MEAO. It is concluded that the antioxidant additive very effective in increasing the oxidation stability and in controlling the NOx emission. Further, the addition of antioxidant additive is slight increase the HC, CO and smoke emissions. Hence, A-tocopherol acetate is very effective in controlling the NOx emission with MEAO operated diesel engine without any major modification.

  13. 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.

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

    DOEpatents

    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.

  15. 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

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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,...

  1. 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,...

  2. 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,...

  3. 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,...

  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. NO(x) reduction additives for aircraft gas turbine engines

    NASA Technical Reports Server (NTRS)

    Adelman, Henry G.; Menees, Gene P.; Cambier, Jean-Luc

    1993-01-01

    The reduction of oxides of nitrogen (NO(x)) emissions from aircraft gas turbine engines is a vital part of the NASA High Speed Research Program. Emissions reductions are critical to the feasibility of future High Speed Civil Transports which operate at supersonic speeds in the stratosphere. It is believed that large fleets of such aircraft using conventional gas turbine engines would emit levels of NO(x) that would be harmful to the stratospheric ozone layer. Previous studies have shown that NO(x) emissions can be reduced from stationary powerplant exhausts by the addition of additives such as ammonia to the exhaust gases. Since the exhaust residence times, pressures and temperatures may be different for aircraft gas turbines, a study has been made of additive effectiveness for high speed, high altitude flight.

  6. 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.

  7. 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...

  8. 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.

  9. 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.

  10. Effect of advanced aftertreatment for PM and NOx reduction on heavy-duty diesel engine ultrafine particle emissions.

    PubMed

    Herner, Jorn Dinh; Hu, Shaohua; Robertson, William H; Huai, Tao; Chang, M-C Oliver; Rieger, Paul; Ayala, Alberto

    2011-03-15

    Four heavy-duty and medium-duty diesel vehicles were tested in six different aftertreament configurations using a chassis dynamometer to characterize the occurrence of nucleation (the conversion of exhaust gases to particles upon dilution). The aftertreatment included four different diesel particulate filters and two selective catalytic reduction (SCR) devices. All DPFs reduced the emissions of solid particles by several orders of magnitude, but in certain cases the occurrence of a volatile nucleation mode could increase total particle number emissions. The occurrence of a nucleation mode could be predicted based on the level of catalyst in the aftertreatment, the prevailing temperature in the aftertreatment, and the age of the aftertreatment. The particles measured during nucleation had a high fraction of sulfate, up to 62% of reconstructed mass. Additionally the catalyst reduced the toxicity measured in chemical and cellular assays suggesting a pathway for an inverse correlation between particle number and toxicity. The results have implications for exposure to and toxicity of diesel PM.

  11. 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.

  12. 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.

  13. 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...

  14. 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...

  15. 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...

  16. 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...

  17. Study of Lean NOx Technology for Diesel Emission Control

    SciTech Connect

    Mital, R.

    2000-08-20

    Diesel engines because of their reliability and efficiency are a popular mobile source. The diesel engine operates at higher compression ratios and with leaner fuel mixtures and produces lower carbon monoxide and hydrocarbon emissions. The oxygen-rich environment leads to higher nitrogen oxides in the form of NO. Catalysts selectively promoting the reduction of NOx by HCs in a lean environment have been termed lean NOx catalyst ''LNC''. The two groups that have shown most promise are, Copper exchanged zeolite Cu/ZSM5, and Platinum on alumina Pt/Al2O3.

  18. 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.

  19. 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...

  20. 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

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. Satellite measurements of daily variations in soil NOx emissions

    NASA Astrophysics Data System (ADS)

    Bertram, Timothy H.; Heckel, Andreas; Richter, Andreas; Burrows, John P.; Cohen, Ronald C.

    2005-12-01

    Soil NOx emission from agricultural regions in the western United States has been investigated using satellite observations of NO2 from the SCIAMACHY instrument. We show that the SCIAMACHY observations over a 2 million hectare agricultural region in Montana capture the short intense NOx pulses following fertilizer application and subsequent precipitation and we demonstrate that these variations can be reproduced by tuning the mechanistic parameters in an existing model of soil NOx emissions.

  11. 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.

  12. 40 CFR 96.154 - Compliance with CAIR NOX emissions limitation.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 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...

  13. 40 CFR 96.154 - Compliance with CAIR NOX emissions limitation.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 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...

  14. 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

  15. 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.

  16. 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

  17. 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

  18. 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

  19. 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

  20. 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.

  1. 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...

  2. 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...

  3. 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...

  4. 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...

  5. 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...

  6. 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

    ... 40 Protection of Environment 16 2010-07-01 2010-07-01 false Optional SO2, NOX, and CO2 emissions... § 75.19 Optional SO2, NOX, and CO2 emissions calculation for low mass emissions (LME) units. (a... input, NOX, SO2, and CO2 mass emissions, and NOX emission rate under this part. If the owner or...

  7. 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

    ... 40 Protection of Environment 17 2012-07-01 2012-07-01 false Optional SO2, NOX, and CO2 emissions... § 75.19 Optional SO2, NOX, and CO2 emissions calculation for low mass emissions (LME) units. (a... input, NOX, SO2, and CO2 mass emissions, and NOX emission rate under this part. If the owner or...

  8. NOx Emissions from Diesel Passenger Cars Worsen with Age

    SciTech Connect

    Chen, Yuche; Borken-Kleefeld, Jens

    2016-04-05

    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.

  9. NOx emissions from diesel passenger cars worsen with age

    DOE PAGES

    Chen, Yuche; Borken-Kleefeld, Jens

    2016-02-17

    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 formore » the observed deterioration, depending on the country and its share of diesel cars. Finally, we suggest monitoring the stability of emission controls particularly for high-mileage light commercial as well as heavy-duty vehicles.« less

  10. 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.

  11. 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...

  12. The National Emissions Inventory Significantly Overestimates NOx Emissions: Analysis of CMAQ and in situ observations from DISCOVER-AQ

    NASA Astrophysics Data System (ADS)

    Anderson, D. C.; Dickerson, R. R.; Loughner, C.

    2013-12-01

    NOx and CO not only adversely impact human health, but they, along with associated VOCs, are also important precursors for O3 formation. While ambient NOx and CO concentrations have decreased dramatically over the past 10-20 years, O3 has remained a more recalcitrant problem, particularly in the Baltimore/Washington region. Reduction of O3 production requires that emissions inventories, such as the National Emissions Inventory (NEI), accurately capture total emissions of CO and NOx while also correctly apportioning them among different sectors. Previous evaluations of the NEI paint different pictures of its accuracy, with assertions that it overestimates either one or both of CO and NOx from anywhere between 25 percent to a factor of 2. These conflicting claims warrant further investigation. In this study, measurements of NOx and CO taken aboard the NOAA P3B airplane during the 2011 DISCOVER-AQ field campaign were used to determine the NOx/CO emissions ratio at 6 locations in the Washington/Baltimore region. An average molar emissions ratio of 12.8 × 1.2 CO/NOx was found by calculating the change in CO over the change in NOx from vertical concentration profiles in the planetary boundary layer. Ratios showed little variation with location. Observed values were approximately a factor of 1.35 - 1.75 times greater than that predicted by the annual, countywide emissions ratio from the 2008 NEI. When compared to a temporalized, gridded version of the inventory processed by SMOKE, ratio observations were greater than that predicted by inventories by up to a factor of 2. Comparison of the in situ measurements and remotely sensed observations from MOPITT of CO to the Community Multiscale Air Quality (CMAQ) model agree within 10-35 percent, with the model higher on average. Measurements of NOy by two separate analytical techniques, on the other hand, show that CMAQ consistently and significantly overestimates NOy concentrations. Combined with the CO observations, this

  13. Megacity NOx emissions and lifetimes probed from space

    NASA Astrophysics Data System (ADS)

    Beirle, S.; Boersma, K. F.; Platt, U.; Lawrence, M.; Wagner, T.

    2012-04-01

    Megacity emission inventories, based on bottom-up estimates, are still highly uncertain, in particular in developing countries. Satellite observations have been demonstrated to allow regional and global top-down emission estimates of nitrogen oxides (NOx=NO+NO2), but require poorly quantified a-priori information on the lifetime of NOx.Here we present a new method for the determination of megacity NOx emissions and lifetimes from satellite measurements. Mean patterns of NO2 tropospheric columns are analyzed separately for a set of different wind direction sectors. From the combined use of the observed total burden and the downwind evolution of NO2, mean NOx photochemical lifetimes and total emissions are derived simultaneously. Typical daytime lifetimes of about 4 hours are found for several megacities at low and mid- latitudes, corresponding to mean OH concentrations of ~6e6 molec/cm3 around noon. The derived emissions are generally in good agreement with bottom-up inventories, but are significantly higher in e.g. the case of Riyadh (Saudi Arabia).The presented method works best for isolated "hot spots" of NOx emissions. For megacities in the vicinity (in terms of some hundred km) of other strong sources, like e.g. Paris, modified approaches are necessary. We will present different approaches, and the estimated emissions+uncertainties will be discussed in perspective of existing, bottom-up emission inventories.

  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. 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

  16. 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

  17. NOx emission trends in megacities derived from satellite measurements

    NASA Astrophysics Data System (ADS)

    Konovalov, Igor; Beekmann, Matthias; Richter, Andreas

    2010-05-01

    The effects of air pollutant emissions on both local air quality in megacities and composition of the atmosphere on regional and global scales are currently an important issue of atmospheric researches. In order to properly evaluate these effects, atmospheric models should be provided with accurate information on emissions of major air pollutants. However, such information is frequently very uncertain, as it is documented in literature. The quantification of emissions and related effects is an especially difficult task in the case of developing countries. Recently, it has been demonstrated that satellite measurements of nitrogen dioxide (NO2) can be used as a source of independent information on NOx emissions. In particular, the satellite measurements were used in our earlier studies to improve spatial allocation of NOx emissions, to estimate multi-annual changes of NOx emissions on regional scales and to validate data of traditional emission inventories (see Ref. 1, 2). The goals of the present study are (1) developing an efficient method for estimation of NOx emissions trend in megacity regions by using satellite measurements and an inverse modeling technique and (2) obtaining independent estimates of NOx emission trends in several megacities in Europe and the Middle East in the period from 1996 to 2008. The study is based on the synergetic use of the data for tropospheric NO2 column amounts derived from the long-term GOME and SCIAMACHY measurements and simulations performed by the CHIMERE chemistry transport model. We performed the analysis involving methods of different complexity ranging from estimation of linear trends in the tropospheric NO2 columns retrieved from satellite measurements to evaluation of nonlinear trends in NOx emission estimates obtained with the inverse modeling approach, which, in the given case, involves only very simple and transparent formulations. The most challenging part of the study is the nonlinear trend estimation, which is

  18. 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.

  19. 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

  20. 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.

  1. 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.

  2. 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.

  3. The climate impact of ship NOx emissions: uncertainties due to plume chemistry

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

    Ships are an important source of reactive trace gases in the marine atmosphere, comprising about 17% of total anthropogenic NOx emissions. In the marine environment, ship NOx emissions generate ozone (O3) and hydroxyl radicals (OH) more efficiently than in continental air. Global atmospheric chemistry and transport models (CTMs) have found that ship NOx cools Earth's climate because reductions in methane radiative forcing (RF) due to the OH enhancements more than compensate for warming caused by ship-induced ozone. These past model studies, however, all assumed that the concentrated plumes of ship exhaust are instantly diluted into a grid cell spanning hundreds of kilometers. This expedient but inaccurate model assumption overestimates ozone and OH production, because the affected models bypass the early stages of plume evolution when high NOx concentrations intensify NOx chemical losses. We provide here the first estimate of RF from ship NOx that accounts for sub-grid-scale ship plume chemistry. First, we improve the plume-in-grid representation of exhaust gas chemistry, which is derived from a plume dispersion model, in the GEOS-Chem global CTM. The CTM now calculates methane oxidation within exhaust plumes for the first time, where OH concentrations are 2-3 times greater than background air. We also account for the effect of wind speed on ozone production and losses of NOx and methane in young plumes. We evaluate the CTM against airborne measurements of NOx and ozone over the ocean. The global ship-induced perturbations to ozone and methane concentrations in the improved model are smaller than suggested by the ensemble of past global modeling studies. If we assume instant dilution of ship NOx emissions in our CTM, we can reproduce the past model results, but ozone production is overestimated by 20% and the resulting ozone column enhancements and RF by 40%. Thus, the ozone and methane RF components from ship NOx are likely much smaller than suggested by past

  4. 40 CFR 96.354 - Compliance with CAIR NOX emissions limitation.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 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...

  5. 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 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...

  6. 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...

  7. 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...

  8. 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...

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

    PubMed

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

    2016-06-07

    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.

  10. Effect of Steam Addition on the Flow Field and NOx Emissions for Jet-A in an Aircraft Combustor

    NASA Astrophysics Data System (ADS)

    Xue, Rui; Hu, Chunbo; Nikolaidis, Theoklis; Pilidis, Pericle

    2016-12-01

    The steam injection technology for aircraft engines is gaining rising importance because of the strong limitations imposed by the legislation for NOx reduction in airports. In order to investigate the impact of steam addition on combustion and NOx emissions, an integrated performance-CFD-chemical reactor network (CRN) methodology was developed. The CFD results showed steam addition reduced the high temperature size and the radical pool moved downstream. Then different post-processing techniques are employed and CRN is generated to predict NOx emissions. This network consists of 14 chemical reactor elements and the results were in close agreement with the ICAO databank. The established CRN model was then used for steam addition study and the results showed under air/steam mixture atmosphere, high steam content could push the NOx formation region to the post-flame zone and a large amount of the NOx emission could be reduced when the steam mass fraction is quite high.

  11. Application of an EGR system in a direct injection diesel engine to reduce NOx emissions

    NASA Astrophysics Data System (ADS)

    De Serio, D.; De Oliveira, A.; Sodré, J. R.

    2016-09-01

    This work presents the application of an exhaust gas recirculation (EGR) system in a direct injection diesel engine operating with diesel oil containing 7% biodiesel (B7). EGR rates of up to 10% were applied with the primary aim to reduce oxides of nitrogen (NOx) emissions. The experiments were conducted in a 44 kW diesel power generator to evaluate engine performance and emissions for different load settings. The use of EGR caused a peak pressure reduction during the combustion process and a decrease in thermal efficiency, mainly at high engine loads. A reduction of NOx emissions of up to 26% was achieved, though penalizing carbon monoxide (CO) and total hydrocarbons (THC) emissions.

  12. 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.; Xiao, X.; Zhou, W.; Henderson, B. H.; Lash, B.

    2014-09-01

    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 (VCD) is further reduced by increasing modeled NOx lifetime and adding an artificial amount of NO2 in the upper troposphere. The sector-based DKF inversion tends to scale down area and non-road 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 inverted 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 and increases the model correlation with ground measurement in O3 simulations and makes O3 more sensitive to NOx emissions in the O3 non-attainment areas.

  13. 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.

  14. 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.

  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. Comparison of NOx emissions from China III and China IV in-use diesel trucks based on on-road measurements

    NASA Astrophysics Data System (ADS)

    Yao, Zhiliang; Wu, Bobo; Wu, Yunong; Cao, Xinyue; Jiang, Xi

    2015-12-01

    To mitigate NOx and other emissions from diesel vehicles, China I, China II, China III and China IV emissions standards for new vehicles have been implemented nationwide. However, recent on-road measurements using a portable emission measurement system (PEMS) have revealed no significant reductions in the NOx emissions factors of diesel trucks due to the change from China II emissions standards to the more stringent China III standards. Thus, it is important to understand the effect of the China IV emissions standard on NOx emissions. In this study, nine China III and nine China IV diesel trucks of three sizes (light-duty diesel trucks (LDDTs), medium-duty diesel trucks (MDDTs) and heavy-duty diesel trucks (HDDTs)) were tested on real roads in Beijing using a PEMS. Compared to the tested China III diesel trucks, the China IV diesel trucks showed significant reductions of the average NOx emissions factors in terms of both distance travelled and fuel consumption. However, the driving conditions had an important impact on the reduction. Under non-highway driving (NHD), several of the tested China IV diesel trucks experienced no reduction or an increase in NOx emissions compared to their China III counterparts. The NOx emissions factors of the 18 tested diesel trucks under NHD were on average 1.5-times greater than those under highway driving (HD), and the effects on NOx emissions removal from China III to China IV diesel trucks were greater under HD than under NHD. In addition, no significant reduction of NOx based on fuel consumption for China IV diesel trucks was observed for MDDTs and HDDTs compared to the test results for similar China II vehicles reported in a previous study. To reduce NOx emissions in China, additional control measures of vehicular NOx emissions should be formulated.

  17. 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

  18. Demonstration of selective catalytic reduction (SCR) technology for the control of nitrogen oxides (NOx) emissions from high sulfur coal-fired utility boilers at Plant Crist SCR test facility

    SciTech Connect

    Hinton, W.S.; Maxwell, J.D.; Baldwin, A.L.

    1996-01-01

    This paper describes the status of the Innovative Clean Coal Technology project to demonstrate SCR technology for reduction of NOx emissions from flue gas of utility boilers burning U.S. high-sulfur coal. The project is sponsored by the U.S. Department of Energy, managed and co- funded by Southern Company Services, Inc. on behalf of the Southern Company, and also co-funded by the Electric Power Research Institute and Ontario Hydro; and is located at Gulf Power Company`s Plant Crist Unit 5 (75 MW tangentially-fired boiler burning U.S. coals that have a sulfur content near 3.0%), near Pensacola, Florida. The test program is being conducted for approximately two years to evaluate catalyst deactivation and other SCR operational effects. The SCR test facility has nine reactors: three 2.5 MW (5000 scfm), and six 0.2 MW(400 scfm). Eight reactors operate on high-dust flue gas, while the ninth reactor operates on low-dust flue gas using a slip stream at the exit of the host unit`s hot side precipitator. The reactors operate in parallel with commercially available SCR catalysts obtained from vendors throughout the world. Long-term performance testing began in July 1993. A general test facility description and the results from three parametric test sequences and long term test data through December 1994 are presented in this paper.

  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. 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...

  1. 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...

  2. 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...

  3. 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...

  4. 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.

  5. 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...

  6. 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.

  7. 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

  8. 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.

  9. 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.

  10. 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...

  11. 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...

  12. 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...

  13. 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...

  14. 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...

  15. Advanced combustion techniques for controlling NO/x/ emissions of high altitude cruise aircraft

    NASA Technical Reports Server (NTRS)

    Rudey, R. A.; Reck, G. M.

    1976-01-01

    An array of experiments have been and continue to be sponsored and conducted by NASA to explore the potential of advanced combustion techniques for controlling the emissions of aircraft into the upper atmosphere. Of particular concern are the oxides of nitrogen (NO/x/) emissions into the stratosphere. The experiments utilize a wide variety of approaches varying from advanced combustor concepts to fundamental flame tube experiments. Results are presented which indicate that substantial reductions in cruise NO/x/ emissions should be achievable in future aircraft engines. A major NASA program is described which focuses the many fundamental experiments into a planned evolution and demonstration of the prevaporized-premixed combustion technique in a full-scale engine.

  16. Satellite observations of NOx and VOC emissions from fires

    NASA Astrophysics Data System (ADS)

    Zoogman, P.; Chance, K.; Huang, G.; Gonzalez Abad, G.; Miller, C. E.; Nowlan, C. R.; Liu, X.

    2015-12-01

    We present estimates of NOx, formaldehyde, and glyoxal emissions from biomass burning events derived from enhancements measured by OMI (Ozone Monitoring Instrument). Emissions from biomass burning can vary greatly both regionally and from event to event, but previous work has been unable to fully explain this variability. Satellite observations from OMI offer a powerful tool to observe biomass burning events by providing observations globally over a range of environmental conditions that effect emissions of NOx, formaldehyde, and glyoxal. We will expand on previous studies by using OMI measurements to investigate not only the dependence of the emissions of each of these species on fire intensity but also the dependence of the ratios of these species. Fire intensity is quantified by using fire radiative power quantified by the MODIS (Moderate-Resolution Imaging Spectrometer) satellite instrument. We also account for variation of emissions and their ratios due to available fuel loading and fire types, which are affected by regional (e.g. biome type) and meteorological (e.g. wind, temperature, rainfall) factors. Furthermore, in individual case studies we will constrain how the chemical processing of primary fire emissions effects the secondary formation of VOCs and ozone by exploiting the temporal and spatial evolution of these interspecies relationships.

  17. 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.

  18. On-road measurements of vehicle NO2/NOx emission ratios in Denver, Colorado, USA

    NASA Astrophysics Data System (ADS)

    Wild, Robert J.; Dubé, William P.; Aikin, Kenneth C.; Eilerman, Scott J.; Neuman, J. Andrew; Peischl, Jeff; Ryerson, Thomas B.; Brown, Steven S.

    2017-01-01

    Nitrogen oxides (NOx = NO + NO2) emitted by on-road combustion engines are important contributors to tropospheric ozone production. The NOx fraction emitted as nitrogen dioxide (NO2) is usually presumed to be small but can affect ozone production and distribution, and this fraction is generally not reported in emissions inventories. We have developed an accurate method for determination of this primary NO2 emission and demonstrated it during measurement of on-road vehicle emission plumes from a mobile laboratory during July and August 2014 in the region between Denver and Greeley in Colorado. During a total of approximately 90 h of sampling from an instrumented mobile laboratory, we identified 1867 vehicle emission plumes, which were extracted using an algorithm that looks for rapid and large increases in measured NOx. We find a distribution of NO2/NOx emissions similar to a log-normal profile, with an average emission ratio of 0.053 ± 0.002 per sampled NOx plume. The average is not weighted by the total NOx emissions from sampled vehicles, which is not measured here, and so may not represent the NO2/NOx ratio of the total NOx emission if this ratio is a function of NOx itself. Although our current data set does not distinguish between different engine types (e.g., gasoline, light duty diesel and heavy duty diesel), the ratio is on the low end of recent reports of vehicle fleet NO2 to NOx emission ratios in Europe.

  19. 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.

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

    DOE PAGES

    Gunnarsson, Fredrik; Pihl, Josh A.; Toops, Todd J.; ...

    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

  1. 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

    2013-05-07

    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.

  2. 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.

  3. 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.

  4. 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...

  5. 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.

  6. 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.

  7. Plasma Catalysis for NOx Reduction from Light-Duty Diesel Vehicles

    SciTech Connect

    Barlow, Stephan E.; Kwak, Ja Hun; Peden, Charles HF; Szanyi, Janos; Tonkyn, Russell G.; Singh, Gurpreet; Stork, Kevin; Hoard, John W.; Cho, Byong; Brooks, David J.; Nunn, Steven

    2004-10-01

    This annual report reviews FY 2003 progress of a program aimed at the development of a novel plasma/catalyst technology for the remediation of NOx under lean (excess oxygen) conditions, specifically for compression ignition direct injection (CIDI) diesel engines that have significant fuel economy benefits over conventional stoichiometric gasoline engines. Our previous work has shown that a non-thermal plasma in combination with an appropriate catalyst can provide NOx emission reduction efficiency of 60-80% using a simulated diesel exhaust. Based on these levels of NOx reduction obtained in the lab, a simple model was developed in this program that allows for the estimation of the fuel economy penalty that would be incurred by operating a plasma/catalyst system. Results obtained from this model suggest that a 5% fuel economy penalty is achievable with the then current (FY2000) state-of-the-art catalyst materials and plasma reactor designs. In this last year, we have continued to focus on (1) improving the catalyst and plasma reactor efficiencies for NOx reduction, (2) studies to reveal important details of the reaction mechanism(s) that can then guide our catalyst and reactor development efforts (focus 1), and (3) evaluating the performance of prototype systems on real engine exhaust. While studies of the effects of the plasma on PM in real diesel engine exhaust is meant to be part of the program, this year we did not conduct any experiments along these lines due to the major effort required to carry out the engine testing (focus 3).

  8. Influence of calcium content of biomass-based materials on simultaneous NOx and SO{sub 2} reduction

    SciTech Connect

    Sarma V. Pisupati; Sumeet Bhalla

    2008-04-01

    Pyrolysis products of biomass (bio-oils) have been shown to cause a reduction in NOx emissions when used as reburn fuels in combustion systems. When these bio-oils are processed with lime, calcium is ion-exchanged and the product is called BioLime. BioLime, when introduced into a combustion chamber, pyrolyzes and produces volatile products that reduce NOx emissions through reburn mechanisms. Simultaneously, calcium reacts with SO{sub 2} to form calcium sulfate and thus reduces SO{sub 2} emissions. This paper reports the characterization of composition and pyrolysis behavior of two BioLime products and the influence of feedstock on pyrolysis products. Thermogravimetric analysis (TGA) and {sup 13}C-CP/MAS NMR techniques were used to study the composition of two biomass-based materials. The composition of the pyrolysis products of BioLime was determined in a laboratory scale flow reactor. The effect of BioLime composition on NOx and SO{sub 2} reduction performance was evaluated in a 146.5 kW pilot-scale, down fired combustor (DFC). The effect of pyrolysis gas composition on NOx reduction is discussed. The TGA weight loss curves of BioLime samples in an inert atmosphere showed two distinct peaks corresponding to the decomposition of light and heavy components of the BioLime and a third distinct peak corresponding to secondary thermal decomposition of char. The study also showed that BioLime sample with lower content of residual lignin derivatives and lower calcium content produced more volatile compounds upon pyrolysis in the combustor and achieved higher NOx reduction (15%). Higher yields of pyrolysis gases increased the NO reduction potential of BioLime through homogeneous gas phase reactions. Calcium in BioLime samples effectively reduced SO{sub 2} emissions (60-85%). 36 refs., 6 figs., 3 tabs.

  9. 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;

  10. 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.

  11. 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

    ... maximum potential CO2 concentration or the minimum potential O2 concentration (as applicable). The maximum...) of this section, calculate hourly NOX mass emissions from the hourly NOX concentration (in ppm) and... NOX-diluent continuous emissions monitoring system or NOX concentration monitoring system, the...

  12. 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

    ... maximum potential CO2 concentration or the minimum potential O2 concentration (as applicable). The maximum...) of this section, calculate hourly NOX mass emissions from the hourly NOX concentration (in ppm) and... NOX-diluent continuous emissions monitoring system or NOX concentration monitoring system, the...

  13. 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

    ... maximum potential CO2 concentration or the minimum potential O2 concentration (as applicable). The maximum...) of this section, calculate hourly NOX mass emissions from the hourly NOX concentration (in ppm) and... NOX-diluent continuous emissions monitoring system or NOX concentration monitoring system, the...

  14. 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

    ... maximum potential CO2 concentration or the minimum potential O2 concentration (as applicable). The maximum...) of this section, calculate hourly NOX mass emissions from the hourly NOX concentration (in ppm) and... NOX-diluent continuous emissions monitoring system or NOX concentration monitoring system, the...

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

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... maximum potential CO2 concentration or the minimum potential O2 concentration (as applicable). The maximum...) of this section, calculate hourly NOX mass emissions from the hourly NOX concentration (in ppm) and... NOX-diluent continuous emissions monitoring system or NOX concentration monitoring system, the...

  16. 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

  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. In-use NOx emissions from model year 2010 and 2011 heavy-duty diesel engines equipped with aftertreatment devices.

    PubMed

    Misra, Chandan; Collins, John F; Herner, Jorn D; Sax, Todd; Krishnamurthy, Mohan; Sobieralski, Wayne; Burntizki, Mark; Chernich, Don

    2013-07-16

    The California Air Resources Board (ARB) undertook this study to characterize the in-use emissions of model year (MY) 2010 or newer diesel engines. Emissions from four trucks: one equipped with an exhaust gas recirculation (EGR) and three equipped with EGR and a selective catalytic reduction (SCR) device were measured on two different routes with three different payloads using a portable emissions measurement system (PEMS) in the Sacramento area. Results indicated that brake-specific NOx emissions for the truck equipped only with an EGR were independent of the driving conditions. Results also showed that for typical highway driving conditions, the SCR technology is proving to be effective in controlling NOx emissions. However, under operations where the SCR's do not reach minimum operating temperature, like cold starts and some low load/slow speed driving conditions, NOx emissions are still elevated. The study indicated that strategies used to maintain exhaust temperature above a certain threshold, which are used in some of the newer SCRs, have the potential to control NOx emissions during certain low-load/slow speed driving conditions.

  19. Non-OEM experience with NOx reduction applications

    SciTech Connect

    Birchett, K.S.; Chung, L.; Caldwell, R.E.; Crisler, M.L.

    1996-01-01

    Heightened global environmental awareness and mandated deadlines for emission compliance required by the Clean Air Act, demand operators to increase controls on boiler emissions. For decades, the utility boiler industry has been dominated by the large OEM`s. In the past, boiler owners would approach the company that originally designed the boiler or burner system to design a burner system to reduce emissions. It was commonly believed that the boiler manufacturer had the greatest expertise in the area of NO{sub x} reduction. Current experience demonstrates that boiler owners are accepting new approaches to reducing NO{sub x} from non-OEM designers and suppliers. This paper outlines new approaches being applied by boiler operators to reduce NO{sub x} emissions. Several steps are imperative for a successful NO{sub x} reduction program and each step of this process will be described with examples presented. Concepts that will be examined are: (1) Practical designing concerns of theoretical Low NO{sub x} combustion, (2) Reviewing scope requirements required to reduce emissions, and (3) Teaming with the Customer to facilitate retrofit design and installation. The emphasis of this paper is not directed at the theory of how the components reduce NO{sub x}, but how to effectively apply proven technology that reduced NO{sub x} emissions.

  20. 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.

  1. 40 CFR 1037.102 - Exhaust emission standards for NOX, HC, PM, and CO.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ..., PM, and CO. 1037.102 Section 1037.102 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... and Related Requirements § 1037.102 Exhaust emission standards for NOX, HC, PM, and CO. See 40 CFR part 86 for the exhaust emission standards for NOX, HC, PM, and CO that apply for heavy-duty vehicles....

  2. 40 CFR 1037.102 - Exhaust emission standards for NOX, HC, PM, and CO.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ..., PM, and CO. 1037.102 Section 1037.102 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... and Related Requirements § 1037.102 Exhaust emission standards for NOX, HC, PM, and CO. See 40 CFR part 86 for the exhaust emission standards for NOX, HC, PM, and CO that apply for heavy-duty vehicles....

  3. 40 CFR 1037.102 - Exhaust emission standards for NOX, HC, PM, and CO.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ..., PM, and CO. 1037.102 Section 1037.102 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... and Related Requirements § 1037.102 Exhaust emission standards for NOX, HC, PM, and CO. See 40 CFR part 86 for the exhaust emission standards for NOX, HC, PM, and CO that apply for heavy-duty vehicles....

  4. 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

  5. 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...

  6. Satellite observations indicate substantial spatiotemporal variability in biomass burning NOx emission factors for South America

    NASA Astrophysics Data System (ADS)

    Castellanos, P.; Boersma, F.; van der Werf, G.

    2013-12-01

    Biomass burning is an important contributor to global total emissions of NOx (NO+NO2). Generally bottom-up fire emissions models calculate NOx emissions by multiplying fuel consumption estimates with static biome specific emission factors, defined in units of grams of NO per kilogram of dry matter consumed. Emission factors are a significant source of uncertainty in bottom-up fire emissions modeling because relatively few observations are available to characterize the large spatial and temporal variability of burning conditions. In this paper we use NO2 tropospheric column observations from the Ozone Monitoring Instrument (OMI) from the year 2005 over South America to calculate monthly NOx emission factors for four fire types: deforestation, savanna/grassland, woodland, and agricultural waste burning. In general, the spatial trends in NOx emission factors calculated in this work are consistent with emission factors derived from in situ measurements from the region, but are more variable than published biome specific global average emission factors widely used in bottom up fire emissions inventories such as the Global Fire Emissions Database (GFED) v3. Satellite based NOx emission factors also indicate substantial temporal variability in burning conditions. Overall, we found that deforestation fires have the lowest NOx emission factors, on average 30% lower than the emission factors used in GFED v3. Agricultural fire NOx emission factors were the highest, on average 80% higher than GFED v3 values. For savanna, woodland, and deforestation fires early dry season NOx emission factors were a factor of ~1.5-2.0 higher than late dry season emission factors. A minimum in the NOx emission factor seasonal cycle for deforestation fires occurred in August, the time period of severe drought in South America in 2005. Our results support the hypothesis that prolonged dry spells may lead to an increase in the contribution of smoldering combustion from large diameter fuels to total

  7. Satellite observations indicate substantial spatiotemporal variability in biomass burning NOx emission factors for South America

    NASA Astrophysics Data System (ADS)

    Castellanos, P.; Boersma, K. F.; van der Werf, G. R.

    2013-08-01

    Biomass burning is an important contributor to global total emissions of NOx (NO + NO2). Generally bottom-up fire emissions models calculate NOx emissions by multiplying fuel consumption estimates with static biome specific emission factors, defined in units of grams of NO per kilogram of dry matter consumed. Emission factors are a significant source of uncertainty in bottom-up fire emissions modeling because relatively few observations are available to characterize the large spatial and temporal variability of burning conditions. In this paper we use NO2 tropospheric column observations from the Ozone Monitoring Instrument (OMI) from the year 2005 over South America to calculate monthly NOx emission factors for four fire types: deforestation, savanna/grassland, woodland, and agricultural waste burning. In general, the spatial trends in NOx emission factors calculated in this work are consistent with emission factors derived from in situ measurements from the region, but are more variable than published biome specific global average emission factors widely used in bottom up fire emissions inventories such as the Global Fire Emissions Database (GFED) v3. Satellite based NOx emission factors also indicate substantial temporal variability in burning conditions. Overall, we found that deforestation fires have the lowest NOx emission factors, on average 30 % lower than the emission factors used in GFED v3. Agricultural fire NOx emission factors were the highest, on average a factor of 2 higher than GFED v3 values. For savanna, woodland, and deforestation fires early dry season NOx emission factors were a factor of ~1.5-2.0 higher than late dry season emission factors. A minimum in the NOx emission factor seasonal cycle for deforestation fires occurred in August, the time period of severe drought in South America in 2005. Our results support the hypothesis that prolonged dry spells may lead to an increase in the contribution of smoldering combustion from large diameter

  8. 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... projections contained in its approved SIP submission. (1) Every-year reporting cycle. As applicable,...

  9. 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

  10. 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.

  11. Inverse modelling of NOx emissions over eastern China: uncertainties due to chemical non-linearity

    NASA Astrophysics Data System (ADS)

    Gu, Dasa; Wang, Yuhang; Yin, Ran; Zhang, Yuzhong; Smeltzer, Charles

    2016-10-01

    Satellite observations of nitrogen dioxide (NO2) have often been used to derive nitrogen oxides (NOx = NO + NO2) emissions. A widely used inversion method was developed by Martin et al. (2003). Refinements of this method were subsequently developed. In the context of this inversion method, we show that the local derivative (of a first-order Taylor expansion) is more appropriate than the "bulk ratio" (ratio of emission to column) used in the original formulation for polluted regions. Using the bulk ratio can lead to biases in regions of high NOx emissions such as eastern China due to chemical non-linearity. Inverse modelling using the local derivative method is applied to both GOME-2 and OMI satellite measurements to estimate anthropogenic NOx emissions over eastern China. Compared with the traditional method using bulk ratio, the local derivative method produces more consistent NOx emission estimates between the inversion results using GOME-2 and OMI measurements. The results also show significant changes in the spatial distribution of NOx emissions, especially over high emission regions of eastern China. We further discuss a potential pitfall of using the difference of two satellite measurements to derive NOx emissions. Our analysis suggests that chemical non-linearity needs to be accounted for and that a careful bias analysis is required in order to use the satellite differential method in inverse modelling of NOx emissions.

  12. Gaseous nitrous acid (HONO) and nitrogen oxides (NOx) emission from gasoline and diesel vehicles under real-world driving test cycles.

    PubMed

    Trinh, Ha T; Imanishi, Katsuma; Morikawa, Tazuko; Hagino, Hiroyuki; Takenaka, Norimichi

    2017-04-01

    Reactive nitrogen species emission from the exhausts of gasoline and diesel vehicles, including nitrogen oxides (NOx) and nitrous acid (HONO), contributes as a significant source of photochemical oxidant precursors in the ambient air. Multiple laboratory and on-road exhaust measurements have been performed to estimate the NOx emission factors from various vehicles and their contribution to atmospheric pollution. Meanwhile, HONO emission from vehicle exhaust has been under-measured despite the fact that HONO can contribute up to 60% of the total hydroxyl budget during daytime and its formation pathway is not fully understood. A profound traffic-induced HONO to NOx ratio of 0.8%, established by Kurtenbach et al. since 2001, has been widely applied in various simulation studies and possibly linked to under-estimation of HONO mixing ratios and OH radical budget in the morning. The HONO/NOx ratios from direct traffic emission have become debatable when it lacks measurements for direct HONO emission from vehicles upon the fast-changing emission reduction technology. Several recent studies have reported updated values for this ratio. This study has reported the measurement of HONO and NOx emission as well as the estimation of exhaust-induced HONO/NOx ratios from gasoline and diesel vehicles using different chassis dynamometer tests under various real-world driving cycles. For the tested gasoline vehicle, which was equipped with three-way catalyst after-treatment device, HONO/NOx ratios ranged from 0 to 0.95 % with very low average HONO concentrations. For the tested diesel vehicle equipped with diesel particulate active reduction device, HONO/NOx ratios varied from 0.16 to 1.00 %. The HONO/NOx ratios in diesel exhaust were inversely proportional to the average speeds of the tested vehicles.

  13. The Reduction of NOx Using Pulsed Electron Beams

    DTIC Science & Technology

    2015-12-30

    Ladouceur (202) 767-3558 Experimental and computational work conducted at the Naval Research Laboratory (NRL) to reduce NOx pollutants in a surrogate...Division in a collaborative effort with the Plasma Physics Division. Experimental and computational work done at the NRL to reduce NOx pollutants in...nitric oxide (NO) and nitrogen dioxide (NO2) in air . These gases are produced from endothermic reactions between nitrogen and oxygen during high

  14. Tritium Emissions Reduction Facility

    SciTech Connect

    Wieneke, R.E.; Bowser, R.P.; Hedley, W.H.; Kissner, T.J.; Lamberger, P.H.; Morgan, F.G.; Van Patten, J.F.; Williams, M.A.

    1988-01-01

    The Tritium Emissions Reduction Facility (TERF) will be a system for the continuous processing of tritium containing gases collected from various operations at Mound. The basis of the system operation will be the oxidation of elemental hydrogen isotopes and organic molecules at elevated temperatures on precious metal catalyst beds, and the adsorption of the resulting oxide (water) on molecular sieve dryers. The TERF will be expected to handle from 400,000 to 1,000,000 curies of tritium per year in the process gas stream and release no more than 200 curies per year to the atmosphere. Consequently, the TERF will need to convert and capture tritium at low concentrations in gas efficiently and reliably. 5 refs., 2 figs.

  15. 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.

  16. Satellite observations indicate substantial spatiotemporal variability in biomass burning NOx emission factors for South America

    NASA Astrophysics Data System (ADS)

    Castellanos, P.; Boersma, K. F.; van der Werf, G. R.

    2014-04-01

    Biomass burning is an important contributor to global total emissions of NOx (NO+NO2). Generally bottom-up fire emissions models calculate NOx emissions by multiplying fuel consumption estimates with static biome-specific emission factors, defined in units of grams of NO per kilogram of dry matter consumed. Emission factors are a significant source of uncertainty in bottom-up fire emissions modeling because relatively few observations are available to characterize the large spatial and temporal variability of burning conditions. In this paper we use NO2 tropospheric column observations from the Ozone Monitoring Instrument (OMI) from the year 2005 over South America to calculate monthly NOx emission factors for four fire types: deforestation, savanna/grassland, woodland, and agricultural waste burning. In general, the spatial patterns in NOx emission factors calculated in this work are consistent with emission factors derived from in situ measurements from the region but are more variable than published biome-specific global average emission factors widely used in bottom-up fire emissions inventories such as the Global Fire Emissions Database (GFED). Satellite-based NOx emission factors also indicate substantial temporal variability in burning conditions. Overall, we found that deforestation fires have the lowest NOx emission factors, on average 30% lower than the emission factors used in GFED v3. Agricultural fire NOx emission factors were the highest, on average a factor of 1.8 higher than GFED v3 values. For savanna, woodland, and deforestation fires, early dry season NOx emission factors were a factor of ~1.5-2 higher than late dry season emission factors. A minimum in the NOx emission factor seasonal cycle for deforestation fires occurred in August, the time period of severe drought in South America in 2005, supporting the hypothesis that prolonged dry spells may lead to an increase in the contribution of smoldering combustion from large-diameter fuels

  17. Evaluation of Exhaust Emissions from Three Diesel-Hybrid Cars and Simulation of After-Treatment Systems for Ultralow Real-World NOx Emissions.

    PubMed

    Franco, Vicente; Zacharopoulou, Theodora; Hammer, Jan; Schmidt, Helge; Mock, Peter; Weiss, Martin; Samaras, Zissis

    2016-12-06

    Hybridization offers great potential for decreasing pollutant and carbon dioxide emissions of diesel cars. However, an assessment of the real-world emissions performance of modern diesel hybrids is missing. Here, we test three diesel-hybrid cars on the road and benchmark our findings with two cars against tests on the chassis dynamometer and model simulations. The pollutant emissions of the two cars tested on the chassis dynamometer were in compliance with the relevant Euro standards over the New European Driving Cycle and Worldwide harmonized Light vehicles Test Procedure. On the road, all three diesel-hybrids exceeded the regulatory NOx limits (average exceedance for all trips: +150% for the Volvo, +510% for the Peugeot, and +550% for the Mercedes-Benz) and also showed elevated on-road CO2 emissions (average exceedance of certification values: +178, +77, and +52%, respectively). These findings point to a wide discrepancy between certified and on-road CO2 and suggest that hybridization alone is insufficient to achieve low-NOx emissions of diesel powertrains. Instead, our simulation suggests that properly calibrated selective catalytic reduction filter and lean-NOx trap after-treatment technologies can reduce the on-road NOx emissions to 0.023 and 0.068 g/km on average, respectively, well below the Euro 6 limit (0.080 g/km).

  18. Space-based NOx emission estimates over remote regions improved in DECSO

    NASA Astrophysics Data System (ADS)

    Ding, Jieying; van der A, Ronald Johannes; Mijling, Bas; Felicitas Levelt, Pieternel

    2017-03-01

    We improve the emission estimate algorithm DECSO (Daily Emission estimates Constrained by Satellite Observations) to better detect NOx emissions over remote areas. The new version is referred to as DECSO v5. The error covariance of the sensitivity of NO2 column observations to gridded NOx emissions has been better characterized. This reduces the background noise of emission estimates by a factor of 10. An emission update constraint has been added to avoid unrealistic day-to-day fluctuations of emissions. We estimate total NOx emissions, which include biogenic emissions that often drive the seasonal cycle of the NOx emissions. We demonstrate the improvements implemented in DECSO v5 for the domain of East Asia in the year 2012 and 2013. The emissions derived by DECSO v5 are in good agreement with other inventories like MIX. In addition, the improved algorithm is able to better capture the seasonality of NOx emissions and for the first time it reveals ship tracks near the Chinese coasts that are otherwise hidden by the outflow of NO2 from the Chinese mainland. The precision of monthly emissions derived by DECSO v5 for each grid cell is about 20 %.

  19. 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.

  20. Cleaning up the air: effectiveness of air quality policy for SO2 and NOx emissions in China

    NASA Astrophysics Data System (ADS)

    van der A, Ronald J.; Mijling, Bas; Ding, Jieying; Elissavet Koukouli, Maria; Liu, Fei; Li, Qing; Mao, Huiqin; Theys, Nicolas

    2017-02-01

    Air quality observations by satellite instruments are global and have a regular temporal resolution, which makes them very useful in studying long-term trends in atmospheric species. To monitor air quality trends in China for the period 2005-2015, we derive SO2 columns and NOx emissions on a provincial level with improved accuracy. To put these trends into perspective they are compared with public data on energy consumption and the environmental policies of China. We distinguish the effect of air quality regulations from economic growth by comparing them relatively to fossil fuel consumption. Pollutant levels, per unit of fossil fuel, are used to assess the effectiveness of air quality regulations. We note that the desulfurization regulations enforced in 2005-2006 only had a significant effect in the years 2008-2009, when a much stricter control of the actual use of the installations began. For national NOx emissions a distinct decreasing trend is only visible from 2012 onwards, but the emission peak year differs from province to province. Unlike SO2, emissions of NOx are highly related to traffic. Furthermore, regulations for NOx emissions are partly decided on a provincial level. The last 3 years show a reduction both in SO2 and NOx emissions per fossil fuel unit, since the authorities have implemented several new environmental regulations. Despite an increasing fossil fuel consumption and a growing transport sector, the effects of air quality policy in China are clearly visible. Without the air quality regulations the concentration of SO2 would be about 2.5 times higher and the NO2 concentrations would be at least 25 % higher than they are today in China.

  1. 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

  2. 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.

  3. 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.

  4. 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.

  5. Effect of NOx emission controls from world regions on the long-range transport of ozone air pollution and human mortality

    NASA Astrophysics Data System (ADS)

    West, J.; Naik, V.; Horowitz, L. W.

    2007-12-01

    We model the influences of 10% reductions in anthropogenic nitrogen oxide (NOx) emissions from each of nine world regions on surface ozone air quality in that region and all other regions, using the MOZART-2 model of tropospheric chemistry and transport. In doing so, we quantify the relative importance of long-range transport between different world regions for ozone. We find that the strongest inter-regional influences are for Europe to the Former Soviet Union (FSU), East Asia to Southeast Asia, and Europe to Africa. The largest influences per unit of NOx reduced, however, are seen for tropical source regions, due to greater sensitivity of ozone production to NOx emissions. Results show, for example, that NOx reductions in North America are about 20% as effective per ton at reducing ozone in Europe, as NOx reductions from Europe itself. In estimating the changes in cases of premature mortality associated with ozone, we find that NOx reductions in North America, Europe, and FSU reduce more mortalities outside of the source regions than within. Among world regions, an average ton of NOx reduced in India causes the greatest number of avoided mortalities (mainly in India itself). We also assess the long-term increases in global ozone resulting from methane increases due to the regional NOx reductions. For many of the more distant source-receptor pairs, the long-term increase in ozone roughly negates the direct short-term ozone decrease. The increase in methane and long-term ozone per unit of NOx reduced is greatest in tropical source regions and varies among different regions by a factor of ten.

  6. 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.

  7. 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.

  8. 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.

  9. Estimation of NOx emissions from NO2 hotspots in polluted background using satellite observations

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

    Satellite observations have been widely used to study NOx emissions from power plants and cities, which are major NOx sources with large impacts on human health and climate. The quantification of NOx emissions from measured column densities of NO2 requires information on the NOx lifetime, which is typically gained from atmospheric chemistry models. But some recent studies determined the NOx lifetime from the satellite observations as well by analyzing the downwind plume evolution; however, this approach was so far only applied for strong isolated 'point sources' located in clean background, like Riyadh in Saudi Arabia. Here we present a modified method for the quantification of NOx emissions and corresponding atmospheric lifetimes based on OMI observations of NO2, together with ECMWF wind fields, but without further model input, for hot spots located in polluted background. We use the observed NO2 patterns under calm wind conditions as proxy for the spatial patterns of NOx emissions; by this approach, even complex source distributions can be treated realistically. From the change of the spatial patterns of NO2 at larger wind speeds (separately for different wind directions), the effective atmospheric lifetime is fitted. Emissions are derived from integrated NO2 columns above background by division by the corresponding lifetime. NOx lifetimes and emissions are estimated for 19 power plants and 50 cities across China and the US. The derived lifetimes are 3.3 ± 1.2 hours on average with extreme values of 0.9 to 7.7 hours. The resulting very short lifetimes for mountainous sites have been found to be uncertain due to the potentially inaccurate ECMWF wind data in mountainous regions. The derived NOx emissions show overall good agreement with bottom-up inventories.

  10. 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 ...

  11. 40 CFR 51.10 - How does my state report emissions that are required by the NOX SIP Call?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 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...

  12. 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...

  13. 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...

  14. 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...

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

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 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. Observations of a seasonal cycle in NOx emissions from fires in the African savanna

    NASA Astrophysics Data System (ADS)

    Mebust, A. K.; Cohen, R. C.

    2012-12-01

    Nitrogen oxide (NOx) emissions from wildfires account for ~15% of the global total, inducing large fluctuations in the chemical production and loss rates of O3 and CH4 and thereby affecting Earth's radiative balance. NOx emissions from fires depend on fuel N content, combustion stage, and total biomass burned; sparse observations limit current understanding of the variability in these factors across biomes. Here we use satellite-based measurements to study emission coefficients (ECs), a value proportional to emission factors i.e. NOx emitted per unit of biomass burned, from fires in African savannas. NOx ECs decrease steadily across the fire season, rather than remaining constant as is currently assumed. We speculate that this is due to reallocation of nutrients, including N, to plant roots after the growing season. We account for the observed cycle in the GEOS-Chem chemical transport model to show the impacts on monthly tropospheric ozone.

  17. In-use NOx emissions from diesel and liquefied natural gas refuse trucks equipped with SCR and TWC respectively.

    PubMed

    Misra, Chandan; Ruehl, Chris; Collins, John Francis; Chernich, Don; Herner, Jorn

    2017-02-07

    The California Air Resources Board (ARB) and the City of Sacramento undertook this study to characterize the in-use emissions from model year (MY) 2010 or newer diesel, liquefied natural gas (LNG) and hydraulic hybrid diesel engines during real-world refuse truck operation. Emissions from five trucks: two diesels equipped with selective catalytic reduction (SCR), two LNG's equipped with three-way catalyst (TWC) and one hydraulic hybrid diesel equipped with SCR were measured using a portable emissions measurement system (PEMS) in the Sacramento area. Results showed that the brake-specific NOx emissions for the LNG trucks equipped with the TWC catalyst were lowest of all the technologies tested. Results also showed that the brake specific NOx emissions from the conventional diesel engines were significantly higher despite the exhaust temperature being high enough for proper SCR function. Like diesel engines, the brake specific NOx emissions from the hydraulic hybrid diesel also exceeded certification although this can be explained on the basis of the temperature profile. Future studies are warranted to establish whether the below average SCR performance observed in this study is a systemic issue or is it a problem specifically observed during this work.

  18. DOE/NETL's advanced NOx emissions control technology R & D program

    SciTech Connect

    Lani, B.W.; Feeley, T.J. III; Miller, C.E.; Carney, B.A.; Murphy, J.T.

    2006-11-15

    Efforts are underway to provide more cost-effective options for coal-fired power plants to meet stringent emissions limits. Several recently completed DOE/NETL R & D projects were successful in achieving the short-term goal of controlling NOx emissions at 0.15 lb/MMBtu using in-furnace technologies. In anticipation of CAIR and possible congressional multi-pollutant legislation, DOE/NETL issued a solicitation in 2004 to continue R & D efforts to meet the 2007 goal and to initiate R & D targeting the 2010 goal of achieving 0.10 lb/MMBtu using in-furnace technologies in lieu of SCR. As a result, four new NOx R & D projects are currently underway and will be completed over the next three years. The article outlines: ALSTOM's Project on developing an enhanced combustion, low NOx burner for tangentially-fired boilers; Babcock and Wilcox's demonstration of an advanced NOx control technology to achieve an emission rate of 0.10 lb/MMBtu while burning bituminous coal for both wall- and cyclone-fired boilers; Reaction Engineering International's (REI) full-scale field testing of advanced layered technology application (ALTA) NOx control for cyclone fired boilers; and pilot-scale testing of ALTA NOx control of coal-fired boilers also by REI. DOE/NETL has begun an R & D effort to optimize performance of SCR controls to achieve the long term goal of 0.01 lb/MMBtu NOx emission rate by 2020. 1 fig.

  19. 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.

  20. 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.

  1. City-specific vehicle emission control strategies to achieve stringent emission reduction targets in China's Yangtze River Delta region.

    PubMed

    Zhang, Shaojun; Wu, Ye; Zhao, Bin; Wu, Xiaomeng; Shu, Jiawei; Hao, Jiming

    2017-01-01

    The Yangtze River Delta (YRD) region is one of the most prosperous and densely populated regions in China and is facing tremendous pressure to mitigate vehicle emissions and improve air quality. Our assessment has revealed that mitigating vehicle emissions of NOx would be more difficult than reducing the emissions of other major vehicular pollutants (e.g., CO, HC and PM2.5) in the YRD region. Even in Shanghai, where the emission control implemented are more stringent than in Jiangsu and Zhejiang, we observed little to no reduction in NOx emissions from 2000 to 2010. Emission-reduction targets for HC, NOx and PM2.5 are determined using a response surface modeling tool for better air quality. We design city-specific emission control strategies for three vehicle-populated cities in the YRD region: Shanghai and Nanjing and Wuxi in Jiangsu. Our results indicate that even if stringent emission control consisting of the Euro 6/VI standards, the limitation of vehicle population and usage, and the scrappage of older vehicles is applied, Nanjing and Wuxi will not be able to meet the NOx emissions target by 2020. Therefore, additional control measures are proposed for Nanjing and Wuxi to further mitigate NOx emissions from heavy-duty diesel vehicles.

  2. NO sub x reduction by the Econ-Nox trademark SCR process

    SciTech Connect

    Hardison, L.C.; Nagl, G.J.; Addison, G.E. )

    1991-11-01

    SCR systems are used extensively in Japan and West Germany to eliminate 80-90% NO{sub x} emissions from utility boilers and industrial furnace stacks. Costs have been lowered considerably over the past ten years. Further reduced costs and stringent regulations on NO{sub x} emission make this simple system attractive for refinery and industrial process heaters, boilers, and gas turbines. The Econ-Nox{trademark} process uses a fluidized catalyst bed to accomplish selective total reduction of oxides of nitrogen to elemental nitrogen using ammonia as a reactant. The process can be designed for operating temperatures between 550 F and 750 F and for a wide range of operating variables. The process brings together some old technology on selective reduction chemistry, relatively new fluidized bed oxidation techniques and a non-precious metal Econ-Acat{trademark} catalyst which permits operation over a broader temperature range than has been practical in the past. This paper reports some of the distinctions made between this reactor configuration and the historical thermal and catalytic systems used for this type of process.

  3. NOx emission trading in a European context: discussion of the economic, legal, and cultural aspects.

    PubMed

    Dekkers, C P

    2001-10-25

    Emission trading is a new instrument in environmental policy. It is an alien notion in most European countries and it is often viewed with hesitation. The paper discusses the economic, legal, and perhaps more importantly, the cultural aspects to consider when one tries to explore the prospects for trading emissions of NOx and other substances in Europe. Issues to be addressed are the present legal framework in Europe in relation to the national emission ceilings on NOx and other substances on the basis of relevant EU directives and UNECE protocols. The paper will discuss the extent to which the legal framework within the EU imposes constraints on the design of a national emission trading scheme, and what options are available to fit emission trading into that legislative structure. The NOx emission trading programme developed in the Netherlands will be used to demonstrate the various aspects in a European context.

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

    PubMed

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

    2012-11-06

    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.

  5. Low-temperature NOx reduction processes using combined systems of pulsed corona discharge and catalysts

    NASA Astrophysics Data System (ADS)

    Kim, H. H.; Takashima, K.; Katsura, S.; Mizuno, A.

    2001-02-01

    In this paper, we will report NOx removal via reduction processes using two types of combined system of pulse corona discharge and catalysts: the single-stage plasma-driven catalyst (PDC) system, and the two-stage plasma-enhanced selective catalytic reduction (PE-SCR) system. Several catalysts, such as γ-alumina catalysts, mechanically mixed catalysts of γ-alumina with BaTiO3 or TiO2, and Co-ZSM-5 were tested. In the PDC system, which is directly activated by the discharge plasma, it was found that the use of additives was necessary to achieve NOx removal by reduction. Removal rates of NO and NOx were linearly increased as the molar ratio of additive to NOx increased. The dependence of NO and NOx removal on the gas hourly space velocity (GHSV) at a fixed specific input energy (SIE) indicates that plasma-induced surface reaction on the catalyst plays an important role in the PDC system. It was found that the optimal GHSV of the PDC system with the γ-alumina catalyst was smaller than 6000 h-1. Mechanical mixing of γ-alumina with BaTiO3 or TiO2 did not enhance NO and NOx removal and γ-alumina alone was found to be the most suitable catalyst. The dielectric constant of the catalyst only influenced the plasma intensity, not the NOx removal. In the PE-SCR system, plasma-treated NOx (mostly NO2) was reduced effectively with NH3 over the Co-ZSM-5 catalyst at a relatively low temperature of 150 °C. Under optimal conditions the energy cost and energy yield were 25 eV/molecule and 21 g-N (kWh)-1, respectively.

  6. New insights from comprehensive on-road measurements of NOx, NO2 and NH3 from vehicle emission remote sensing in London, UK

    NASA Astrophysics Data System (ADS)

    Carslaw, David C.; Rhys-Tyler, Glyn

    2013-12-01

    In this paper we report the first direct measurements of nitrogen dioxide (NO2) in the UK using a vehicle emission remote sensing technique. Measurements of NO, NO2 and ammonia (NH3) from almost 70,000 vehicles were made spanning vehicle model years from 1985 to 2012. These measurements were carefully matched with detailed vehicle information data to understand the emission characteristics of a wide range of vehicles in a detailed way. Overall it is found that only petrol fuelled vehicles have shown an appreciable reduction in total NOx emissions over the past 15-20 years. Emissions of NOx from diesel vehicles, including those with after-treatment systems designed to reduce emissions of NOx, have not reduced over the same period of time. It is also evident that the vehicle manufacturer has a strong influence on emissions of NO2 for Euro 4/5 diesel cars and urban buses. Smaller-engined Euro 4/5 diesel cars are also shown to emit less NO2 than larger-engined vehicles. It is shown that NOx emissions from urban buses fitted with Selective Catalytic Reduction (SCR) are comparable to those using Exhaust Gas Recirculation for Euro V vehicles, while reductions in NOx of about 30% are observed for Euro IV and EEV vehicles. However, the emissions of NO2 vary widely dependent on the bus technology used. Almost all the NOx emission from Euro IV buses with SCR is in the form of NO, whereas EEV vehicles (Enhanced Environmentally friendly Vehicle) emit about 30% of the NOx as NO2. We find similarly low amounts of NO2 from trucks (3.5-12t and >12t). Finally, we show that NH3 emissions are most important for older generation catalyst-equipped petrol vehicles and SCR-equipped buses. The NH3 emissions from petrol cars have decreased by over a factor of three from the vehicles manufactured in the late 1990s compared with those manufactured in 2012. Tables of emission factors are presented for NOx, NO2 and NH3 together with uncertainties to assist the development of new emission

  7. 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

  8. 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.

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

    PubMed

    Johnson, Jeremiah X; Novacheck, Joshua

    2015-05-05

    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.

  10. 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.

  11. 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.

  12. 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.

  13. Power plant emissions reduction

    DOEpatents

    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.

  14. Asian emissions of CO and NOx: Constraints from aircraft and Chinese station data

    NASA Astrophysics Data System (ADS)

    Wang, Yuxuan X.; McElroy, Michael B.; Wang, Tao; Palmer, Paul I.

    2004-12-01

    Observations of CO and NOy from the Transport and Chemical Evolution over the Pacific (TRACE-P) aircraft mission over the northwest Pacific and from two Chinese ground stations (Hong Kong and Lin An) during spring 2001 are used in conjunction with an optimal estimation inverse model to constrain estimates of Asian emissions of CO and NOx. A priori emissions are based on a detailed bottom-up inventory for the observation period. The inversion analysis requires 43% and 47% increases in Chinese emissions of CO and NOx, respectively, distributed heterogeneously, with the largest adjustments required for central China. A posteriori estimates of emissions from biomass burning in Southeast Asia are much lower than a priori values. Inversion results for NOx emissions are consistent with CO emissions in terms of the sense of the adjustments. Inclusion of the station data in the inversion analysis significantly improves estimates for emissions from central and south China. A large increase in NOx emissions inferred for central China (a factor of 3) is attributed to decomposition of organic wastes associated with the human-animal food chain and extensive applications of chemical fertilizer. An analysis of emission ratios for CO relative to NOx for different sectors indicates that emissions attributed to industry and transportation may be underestimated in the bottom-up inventory for central China, while emissions from the domestic sector may be underestimated for south China. An increase in emission factors could help reconcile results from the inversion analysis with the "bottom-up" approach. Detailed analysis of the surface observations using a posteriori emissions indicates the importance of meteorological phenomena, notably cold fronts in March and small-scale high- and low-pressure systems in April in modulating concentrations of CO, with the latter most evident in the data from Lin An.

  15. 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.

  16. 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.

  17. Reducing NOx emissions from a biodiesel-fueled engine by use of low-temperature combustion.

    PubMed

    Fang, Tiegang; Lin, Yuan-Chung; Foong, Tien Mun; Lee, Chia-Fon

    2008-12-01

    Biodiesel is popularly discussed in many countries due to increased environmental awareness and the limited supply of petroleum. One of the main factors impacting general replacement of diesel by biodiesel is NOx (nitrogen oxides) emissions. Previous studies have shown higher NOx emissions relative to petroleum diesel in traditional direct-injection (DI) diesel engines. In this study, effects of injection timing and different biodiesel blends are studied for low load [2 bar IMEP (indicated mean effective pressure)] conditions. The results show that maximum heat release rate can be reduced by retarding fuel injection. Ignition and peak heat release rate are both delayed for fuels containing more biodiesel. Retarding the injection to post-TDC (top dead center) lowers the peak heat release and flattens the heat release curve. It is observed that low-temperature combustion effectively reduces NOx emissions because less thermal NOx is formed. Although biodiesel combustion produces more NOx for both conventional and late-injection strategies, with the latter leading to a low-temperature combustion mode, the levels of NOx of B20 (20 vol % soy biodiesel and 80 vol % European low-sulfur diesel), B50, and B100 all with post-TDC injection are 68.1%, 66.7%, and 64.4%, respectively, lower than pure European low-sulfur diesel in the conventional injection scenario.

  18. 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.

  19. 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.

  20. An Inter-Regional Comparison of Ozone Sensitivity to Reductions in Emissions in Central California

    NASA Astrophysics Data System (ADS)

    Soong, S.; Tanrikulu, S.; Tran, C.; Jia, Y.; Beaver, S.; Matsuoka, J.; Cordova, J.

    2011-12-01

    Emissions of ozone precursors NOx and VOC have declined significantly in central California over the past 60 years due to rigorous emission control programs, with 40 to 50 percent reductions achieved from 1990 to 2010 alone. Three major air basins, however, are still designated as nonattainment areas for the federal 8-hour ozone standard: the San Francisco Bay Area (SFBA), Sacramento area and the San Joaquin Valley (SJV). Historically, ozone response to reductions in emissions varied from region to region. While the maximum hourly ozone concentrations have declined significantly in all three air basins, the locations of maximum ozone shifted. Some exceedance areas came into compliance with the standard while new areas started exceeding the standard. Some areas did not significantly respond to reductions in emissions. To meet the current ozone standard, additional emission reductions are needed. Further emission reductions above and beyond the goal of meeting the current standard will be needed if the EPA lowers the current standard. In an effort to help planners and decision makers, we have been conducting a modeling study to better understand how ozone may respond to future emission reductions in the region. In this initial phase of the study, we used the WRF-CMAQ modeling system to simulate ozone for July 12-28, 2006, a representative high ozone period for all three air basins. With the selected high grid resolution and optimum model setup, the model performance for the base case simulation was exceptionally good. Statistical agreement with observations was better than most previously applied models in the region. We performed a number of sensitivity simulations by reducing anthropogenic VOC or NOx emissions separately or together 10-60 percent at 10 percent intervals uniformly across the board and prepared EKMA diagrams at observation stations. We found that a 60 percent reduction in VOC and NOx emissions reduced the maximum ozone by 20-30 percent in the

  1. 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

  2. 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

  3. 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

  4. 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.

  5. 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.

  6. 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.

  7. Importance of soil NO emissions for the total atmospheric NOx budget of Saxony, Germany

    NASA Astrophysics Data System (ADS)

    Molina-Herrera, Saúl; Haas, Edwin; Grote, Rüdiger; Kiese, Ralf; Klatt, Steffen; Kraus, David; Kampffmeyer, Tatjana; Friedrich, Rainer; Andreae, Henning; Loubet, Benjamin; Ammann, Christof; Horváth, László; Larsen, Klaus; Gruening, Carsten; Frumau, Arnoud; Butterbach-Bahl, Klaus

    2017-03-01

    Soils are a significant source for the secondary greenhouse gas NO and assumed to be a significant source of tropospheric NOx in rural areas. Here we tested the LandscapeDNDC model for its capability to simulate magnitudes and dynamics of soil NO emissions for 22 sites differing in land use (arable, grassland and forest) and edaphic as well as climatic conditions. Overall, LandscapeDNDC simulated mean soil NO emissions agreed well with observations (r2 = 0.82). However, simulated day to day variations of NO did only agree weakly with high temporal resolution measurements, though agreement between simulations and measurements significantly increased if data were aggregated to weekly, monthly and seasonal time scales. The model reproduced NO emissions from high and low emitting sites, and responded to fertilization (mineral and organic) events with pulse emissions. After evaluation, we linked the LandscapeDNDC model to a GIS database holding spatially explicit data on climate, land use, soil and management to quantify the contribution of soil biogenic NO emissions to the total NOx budget for the State of Saxony, Germany. Our calculations show that soils of both agricultural and forest systems are significant sources and contribute to about 8% (uncertainty range: 6-13%) to the total annual tropospheric NOx budget for Saxony. However, the contributions of soil NO emission to total tropospheric NOx showed a high spatial variability and in some rural regions such as the Ore Mts., simulated soil NO emissions were by far more important than anthropogenic sources.

  8. 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.

  9. 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...

  10. 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

    ... 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 revisions... set forth in § 51.50. (b) For its transport SIP revision under § 51.121, each state must submit to...

  11. 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

    ... 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 revisions... set forth in § 51.50. (b) For its transport SIP revision under § 51.121, each state must submit to...

  12. 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

    ... 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 revisions... set forth in § 51.50. (b) For its transport SIP revision under § 51.121, each state must submit to...

  13. 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.

  14. 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.

  15. 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.

  16. 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

  17. 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.

  18. 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.

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

    DOE PAGES

    Brookshear, Daniel William; Nam, Jeong -Gil; Nguyen, Ke; ...

    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

  20. 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.

  1. The observed response of Ozone Monitoring Instrument (OMI) NO2 columns to NOx emission controls on power plants in the United States: 2005-2011

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

    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 (2005-2011). 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.

  2. 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.

  3. 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

    ...) Install, certify, operate, and maintain a NOX continuous emission monitoring system in the duct to the... the ducts from the affected units; or (B) Develop, demonstrate, and provide information satisfactory..., and maintain a NOX-diluent continuous emission monitoring system in the duct from each affected...

  4. Expected ozone benefits of reducing nitrogen oxide (NOx) emissions from coal-fired electricity generating units in the eastern United States.

    PubMed

    Vinciguerra, Timothy; Bull, Emily; Canty, Timothy; He, Hao; Zalewsky, Eric; Woodman, Michael; Aburn, George; Ehrman, Sheryl; Dickerson, Russell R

    2017-03-01

    On hot summer days in the eastern United States, electricity demand rises, mainly because of increased use of air conditioning. Power plants must provide this additional energy, emitting additional pollutants when meteorological conditions are primed for poor air quality. To evaluate the impact of summertime NOx emissions from coal-fired electricity generating units (EGUs) on surface ozone formation, we performed a series of sensitivity modeling forecast scenarios utilizing EPA 2018 version 6.0 emissions (2011 base year) and CMAQ v5.0.2. Coal-fired EGU NOx emissions were adjusted to match the lowest NOx rates observed during the ozone seasons (April 1-October 31) of 2005-2012 (Scenario A), where ozone decreased by 3-4 ppb in affected areas. When compared to the highest emissions rates during the same time period (Scenario B), ozone increased ∼4-7 ppb. NOx emission rates adjusted to match the observed rates from 2011 (Scenario C) increased ozone by ∼4-5 ppb. Finally in Scenario D, the impact of additional NOx reductions was determined by assuming installation of selective catalytic reduction (SCR) controls on all units lacking postcombustion controls; this decreased ozone by an additional 2-4 ppb relative to Scenario A. Following the announcement of a stricter 8-hour ozone standard, this analysis outlines a strategy that would help bring coastal areas in the mid-Atlantic region closer to attainment, and would also provide profound benefits for upwind states where most of the regional EGU NOx originates, even if additional capital investments are not made (Scenario A).

  5. NOx Storage and Reduction Properties of Model Ceria-based Lean NOx Trap Catalysts

    SciTech Connect

    Shi, Chuan; Ji, Yaying; Graham, Uschi; Jacobs, Gary; Crocker, Mark; Zhang, Zhaoshun; Wang, Yu; Toops, Todd J

    2012-01-01

    Three kinds of model ceria-containing LNT catalysts, corresponding to Pt/Ba/CeO{sub 2}, Pt/CeO{sub 2}/Al{sub 2}O{sub 3} and Pt/BaO/CeO{sub 2}/Al{sub 2}O{sub 3}, were prepared for comparison with a standard LNT catalyst of the Pt/BaO/Al{sub 2}O{sub 3} type. In these catalysts ceria functioned as a No{sub x} storage component and/or a support material. The influence of ceria on the microstructure of the catalysts was investigated, in addition to the effect on No{sub x} storage capacity, regeneration behavior and catalyst performance during lean/rich cycling. The Pt/Ba/CeO{sub 2} and Pt/BaO/CeO{sub 2}/Al{sub 2}O{sub 3} catalysts exhibited higher No{sub x} storage capacity at 200 and 300 C relative to the Pt/BaO/Al{sub 2}O{sub 3} catalyst, although the latter displayed better storage capacity at 400 C. Catalyst regeneration behavior at low temperature was also improved by the presence of ceria, as reflected by TPR measurements. These factors contributed to the superior No{sub x} storage-reduction performance exhibited by the Pt/Ba/CeO{sub 2} and Pt/BaO/CeO{sub 2}/Al{sub 2}O{sub 3} catalysts under cycling conditions in the temperature range 200-300 C. Overall, Pt/BaO/CeO{sub 2}/Al{sub 2}O{sub 3} (which displayed well balanced No{sub x} storage and regeneration behavior), showed the best performance, affording consistently high No{sub x} conversion levels in the temperature range 200-400 C under lean-rich cycling conditions.

  6. Growth in NOx emissions from power plants in China: bottom-up estimates and satellite observations

    NASA Astrophysics Data System (ADS)

    Wang, S. W.; Zhang, Q.; Streets, D. G.; He, K. B.; Martin, R. V.; Lamsal, L. N.; Chen, D.; Lei, Y.; Lu, Z.

    2012-01-01

    Using OMI (Ozone Monitoring Instrument) tropospheric NO2 columns and a nested-grid 3-D global chemical transport model (GEOS-Chem), we investigated the growth in NOx emissions from coal-fired power plants and their contributions to the growth in NO2 columns in 2005-2007 in China. We first developed a unit-based power plant NOx emission inventory for 2005-2007 to support this investigation. The total capacities of coal-fired power generation have increased by 48.8% in 2005-2007, with 92.2% of the total capacity additions coming from generator units with size ≥300 MW. The annual NOx emissions from coal-fired power plants were estimated to be 8.11 Tg NO2 for 2005 and 9.58 Tg NO2 for 2007, respectively. The modeled summer average tropospheric NO2 columns were highly correlated (R2 = 0.79-0.82) with OMI measurements over grids dominated by power plant emissions, with only 7-14% low bias, lending support to the high accuracy of the unit-based power plant NOx emission inventory. The ratios of OMI-derived annual and summer average tropospheric NO2 columns between 2007 and 2005 indicated that most of the grids with significant NO2 increases were related to power plant construction activities. OMI had the capability to trace the changes of NOx emissions from individual large power plants in cases where there is less interference from other NOx sources. Scenario runs from GEOS-Chem model suggested that the new power plants contributed 18.5% and 10% to the annual average NO2 columns in 2007 in Inner Mongolia and North China, respectively. The massive new power plant NOx emissions significantly changed the local NO2 profiles, especially in less polluted areas. A sensitivity study found that changes of NO2 shape factors due to including new power plant emissions increased the summer average OMI tropospheric NO2 columns by 3.8-17.2% for six selected locations, indicating that the updated emission information could help to improve the satellite retrievals.

  7. Growth in NOx emissions from power plants in China: bottom-up estimates and satellite observations

    NASA Astrophysics Data System (ADS)

    Wang, S. W.; Zhang, Q.; Streets, D. G.; He, K. B.; Martin, R. V.; Lamsal, L. N.; Chen, D.; Lei, Y.; Lu, Z.

    2012-05-01

    Using OMI (Ozone Monitoring Instrument) tropospheric NO2 columns and a nested-grid 3-D global chemical transport model (GEOS-Chem), we investigated the growth in NOx emissions from coal-fired power plants and their contributions to the growth in NO2 columns in 2005-2007 in China. We first developed a unit-based power plant NOx emission inventory for 2005-2007 to support this investigation. The total capacities of coal-fired power generation have increased by 48.8% in 2005-2007, with 92.2% of the total capacity additions coming from generator units with size ≥300 MW. The annual NOx emissions from coal-fired power plants were estimated to be 8.11 Tg NO2 for 2005 and 9.58 Tg NO2 for 2007, respectively. The modeled summer average tropospheric NO2 columns were highly correlated (R2 = 0.79-0.82) with OMI measurements over grids dominated by power plant emissions, with only 7-14% low bias, lending support to the high accuracy of the unit-based power plant NOx emission inventory. The ratios of OMI-derived annual and summer average tropospheric NO2 columns between 2007 and 2005 indicated that most of the grids with significant NO2 increases were related to power plant construction activities. OMI had the capability to trace the changes of NOx emissions from individual large power plants in cases where there is less interference from other NOx sources. Scenario runs from GEOS-Chem model suggested that the new power plants contributed 18.5% and 10% to the annual average NO2 columns in 2007 in Inner Mongolia and North China, respectively. The massive new power plant NOx emissions significantly changed the local NO2 profiles, especially in less polluted areas. A sensitivity study found that changes of NO2 shape factors due to including new power plant emissions increased the summer average OMI tropospheric NO2 columns by 3.8-17.2% for six selected locations, indicating that the updated emission information could help to improve the satellite retrievals.

  8. Assessing the photochemical impact of snow NOx emissions over Antarctica during ANTCI 2003

    NASA Astrophysics Data System (ADS)

    Wang, Yuhang; Choi, Yunsoo; Zeng, Tao; Davis, Douglas; Buhr, Martin; Gregory Huey, L.; Neff, William

    Surface and aircraft measurements show large amounts of reactive nitrogen over the Antarctic plateau during the ANTCI 2003 experiment. We make use of 1-D and 3-D chemical transport model simulations to analyze these measurements and assess the photochemical impact of snow NOx emissions. Boundary layer heights measured by SODAR at the South Pole were simulated reasonably well by the polar version of MM5 after a modification of ETA turbulence scheme. The average of model-derived snow NOx emissions (3.2-4.2×108moleccm-2s-1) at the South Pole is similar to the measured flux of 3.9×108moleccm-2s-1 during ISCAT 2000. Daytime snow NOx emission is parameterized as a function of temperature and wind speed. Surface measurements of NO, HNO3 and HNO4, and balloon measurements of NO at the South Pole are reasonably simulated by 1-D and 3-D models. Compared to Twin Otter measurements of NO over plateau regions, 3-D model simulated NO concentrations are at the low end of the observations, suggesting either that the parameterization based on surface measurements at the South Pole underestimates emissions at higher-elevation plateau regions or that the limited aircraft database may not be totally representative for the season of the year sampled. However, the spatial variability of near-surface NO measured by the aircraft is captured by the model to a large extent, indicating that snow NOx emissions are through a common mechanism. An average emission flux of 0.25kgNkm-2month-1 is calculated for December 2003 over the plateau (elevation above 2.5 km). About 50% of reactive nitrogen is lost by deposition and the other 50% by transport. The 3-D model results indicate a shallow but highly photochemically active oxidizing "canopy" enshrouding the entire Antarctic plateau due to snow NOx emissions.

  9. 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

  10. 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.

    2014-02-01

    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 given in the past literature: +3.4 ± 0.85 mW m-2 from the short-lived ozone increase, -5.0 ± 1.1 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 -3.3 ± 1.8 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 composition of the background

  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. 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

  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 Technical Reports Server (NTRS)

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

    2016-01-01

    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 12ppbv decrease in surface O3 concentration over the eastern United States, a slight increase (0.51ppbv) 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. 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.

  15. Comparison of wintertime CO to NOx ratios to MOVES and MOBILE6.2 on-road emissions inventories

    NASA Astrophysics Data System (ADS)

    Wallace, H. W.; Jobson, B. T.; Erickson, M. H.; McCoskey, J. K.; VanReken, T. M.; Lamb, B. K.; Vaughan, J. K.; Hardy, R. J.; Cole, J. L.; Strachan, S. M.; Zhang, W.

    2012-12-01

    The CO-to-NOx molar emission ratios from the US EPA vehicle emissions models MOVES and MOBILE6.2 were compared to urban wintertime measurements of CO and NOx. Measurements of CO, NOx, and volatile organic compounds were made at a regional air monitoring site in Boise, Idaho for 2 months from December 2008 to January 2009. The site is impacted by roadway emissions from a nearby busy urban arterial roads and highway. The measured CO-to-NOx ratio for morning rush hour periods was 4.2 ± 0.6. The average CO-to-NOx ratio during weekdays between the hours of 08:00 and 18:00 when vehicle miles travelled were highest was 5.2 ± 0.5. For this time period, MOVES yields an average hourly CO-to-NOx ratio of 9.1 compared to 20.2 for MOBILE6.2. Off-network emissions are a significant fraction of the CO and NOx emissions in MOVES, accounting for 65% of total CO emissions, and significantly increase the CO-to-NOx molar ratio. Observed ratios were more similar to the average hourly running emissions for urban roads determined by MOVES to be 4.3.

  16. 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.

  17. 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.

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

    DOE PAGES

    Brookshear, Daniel William; Pihl, Josh A.; Toops, Todd J.; ...

    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

  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, 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...

  1. 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...

  2. 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...

  3. 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...

  4. 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...

  5. 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...

  6. 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,...

  7. 40 CFR 75.12 - Specific provisions for monitoring NOX emission rate.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... CO2 concentration in the flue gases. (b) Moisture correction. If a correction for the stack gas... pollutant concentration monitor measures on a different moisture basis from the diluent monitor, the owner... emission rates (in lb/mmBtu) by combining the NOX concentration (in ppm), diluent concentration (in...

  8. 40 CFR 75.12 - Specific provisions for monitoring NOX emission rate.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... CO2 concentration in the flue gases. (b) Moisture correction. If a correction for the stack gas... pollutant concentration monitor measures on a different moisture basis from the diluent monitor, the owner... emission rates (in lb/mmBtu) by combining the NOX concentration (in ppm), diluent concentration (in...

  9. 40 CFR 75.12 - Specific provisions for monitoring NOX emission rate.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... CO2 concentration in the flue gases. (b) Moisture correction. If a correction for the stack gas... pollutant concentration monitor measures on a different moisture basis from the diluent monitor, the owner... emission rates (in lb/mmBtu) by combining the NOX concentration (in ppm), diluent concentration (in...

  10. 40 CFR 75.12 - Specific provisions for monitoring NOX emission rate.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... CO2 concentration in the flue gases. (b) Moisture correction. If a correction for the stack gas... pollutant concentration monitor measures on a different moisture basis from the diluent monitor, the owner... emission rates (in lb/mmBtu) by combining the NOX concentration (in ppm), diluent concentration (in...

  11. 40 CFR 75.12 - Specific provisions for monitoring NOX emission rate.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... CO2 concentration in the flue gases. (b) Moisture correction. If a correction for the stack gas... pollutant concentration monitor measures on a different moisture basis from the diluent monitor, the owner... emission rates (in lb/mmBtu) by combining the NOX concentration (in ppm), diluent concentration (in...

  12. 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.

  13. NOx Emissions Characteristics and Correlation Equations of Two P and W's Axially Staged Sector Combustors Developed Under NASA Environmentally Responsible Aviation (ERA) Project

    NASA Technical Reports Server (NTRS)

    He, Zhuohui J.

    2017-01-01

    Two P&W (Pratt & Whitney)'s axially staged sector combustors have been developed under NASA's Environmentally Responsible Aviation (ERA) project. One combustor was developed under ERA Phase I, and the other was developed under ERA Phase II. Nitrogen oxides (NOx) emissions characteristics and correlation equations for these two sector combustors are reported in this article. The Phase I design was to optimize the NOx emissions reduction potential, while the Phase II design was more practical and robust. Multiple injection points and fuel staging strategies are used in the combustor design. Pilot-stage injectors are located on the front dome plate of the combustor, and main-stage injectors are positioned on the top and bottom (Phase I) or on the top only (Phase II) of the combustor liners downstream. Low power configuration uses only pilot-stage injectors. Main-stage injectors are added to high power configuration to help distribute fuel more evenly and achieve lean burn throughout the combustor yielding very low NOx emissions. The ICAO (International Civil Aviation Organization) landing-takeoff NOx emissions are verified to be 88 percent (Phase I) and 76 percent (Phase II) under the ICAO CAEP/6 (Committee on Aviation Environmental Protection 6th Meeting) standard, exceeding the ERA project goal of 75 percent reduction, and the combustors proved to have stable combustion with room to maneuver on fuel flow splits for operability.

  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. 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.

  16. 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.

  17. Study of Nox Emission Characteristics of a 1025t/h Coal-Fired Circulating Fluidized Bed Boiler

    NASA Astrophysics Data System (ADS)

    Li, Q. Y.; Mi, Z. D.; Zhang, Q. F.

    Measurements of emission are carried out in a 1025t/h CFB boiler. The effect of some factors including coal properties, bed temperature, unit load, excess air on the emission of NOx are investigated. The measurement results show that the N concentration in the coal is dominant parameter to predict the NOx emission from a large-scale CFB boiler. NOx emission from the 1025t/h CFB boiler increases with cyclone temperature and upper pressure drop due to post combustion and external cycle.

  18. Identification of surface NOx emission sources on a regional scale using OMI NO2

    NASA Astrophysics Data System (ADS)

    Zyrichidou, I.; Κoukouli, M. E.; Balis, D.; Markakis, K.; Poupkou, A.; Katragkou, E.; Kioutsioukis, I.; Melas, D.; Boersma, K. F.; van Roozendael, M.

    2015-01-01

    In this study, an inverse modeling technique is applied to obtain, at a regional scale, top-down emission estimates for nitrogen oxides utilizing tropospheric nitrogen dioxide (NO2) columns retrieved by the OMI/Aura instrument and estimated by the Comprehensive Air Quality Model with extensions (CAMx). The main idea, applied previously using models with coarse spatial resolution, is to combine the a priori information from the bottom up emission inventory used in an air quality simulation that covers the Balkan peninsula in a high resolution grid (0.1° × 0.1°) with the tropospheric NO2 quantities estimated for one complete year by CAMx and the tropospheric NO2 columns retrieved by satellite observations in order to identify missing emissions sources on a regional scale. The results have identified biases between the a priori and a posteriori emission inventories due to the missing emission sources or over-estimation of the spread and quantity of certain emission sources. In such a fine resolution grid we have also analyzed and considered the horizontal transport on the a posteriori NOx emissions. The deduced a posteriori NOx emissions, dominated by the fossil fuel emissions, were found to be1.11 ± 0.30 Tg N/y, compared to 0.87 ± 0.43 Tg N/y found in the a priori Balkan emission inventory. Soil emissions over the extended Greek domain, omitted in the a priori inventory, were estimated to account for almost 20% of the total emitted amount, while for the year 2009 the biomass burning NOx emission flux was also estimated and the average rate accounted for 0.5 × 10-6 Tg N/km2.

  19. 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...) of this section. (3) Through 2011, reports are to be submitted according to the schedule in Table 1... reports are to be submitted each year that a triennial report is not required. Table 1—Schedule...

  20. 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...) of this section. (3) Through 2011, reports are to be submitted according to the schedule in Table 1... reports are to be submitted each year that a triennial report is not required. Table 1—Schedule...

  1. 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.

  2. Experimental investigation on NOx and green house gas emissions from a marine auxiliary diesel engine using ultralow sulfur light fuel.

    PubMed

    Geng, Peng; Tan, Qinming; Zhang, Chunhui; Wei, Lijiang; He, Xianzhong; Cao, Erming; Jiang, Kai

    2016-12-01

    In recent years, marine auxiliary diesel engine has been widely used to produce electricity in the large ocean-going ship. One of the main technical challenges for ocean-going ship is to reduce pollutant emissions from marine auxiliary diesel engine and to meet the criteria of disposal on ships pollutants of IMO (International Maritime Organization). Different technical changes have been introduced in marine auxiliary diesel engine to apply clean fuels to reduce pollutant emissions. The ultralow sulfur light fuel will be applied in diesel engine for emission reductions in China. This study is aimed to investigate the impact of fuel (ultralow sulfur light fuel) on the combustion characteristic, NOx and green house gas emissions in a marine auxiliary diesel engine, under the 50%-90% engine speeds and the 25%-100% engine torques. The experimental results show that, in the marine auxiliary diesel engine, the cylinder pressure and peak heat release rate increase slightly with the increase of engine torques, while the ignition advances and combustion duration become longer. With the increases of the engine speed and torque, the fuel consumption decreases significantly, while the temperature of the exhaust manifold increases. The NOx emissions increase significantly with the increases of the engine speed and torque. The NO emission increases with the increases of the engine speed and torque, while the NO2 emission decreases. Meanwhile, the ratio of NO2 and NO is about 1:1 when the diesel engine operated in the low speed and load, while the ratio increases significantly with the increases of engine speed and torque, due to the increase of the cylinder temperature in the diffusive combustion mode. Moreover, the CO2 emission increases with the increases of engine speed and torque by the use of ultralow sulfur light fuel.

  3. 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.

  4. 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

  5. Emission reductions and urban ozone responses under more stringent US standards

    NASA Astrophysics Data System (ADS)

    Downey, Nicole; Emery, Chris; Jung, Jaegun; Sakulyanontvittaya, Tanarit; Hebert, Laura; Blewitt, Doug; Yarwood, Greg

    2015-01-01

    We use a photochemical grid model instrumented with the high-order Decoupled Direct Method (HDDM) to evaluate the response of ozone (O3) to reductions in US-wide anthropogenic emissions, and to estimate emission reductions necessary to meet more stringent National Ambient Air Quality Standards (NAAQS) for O3. We simulate hourly O3 response to nationwide reductions in nitrogen oxides (NOx) and volatile organic compound (VOC) emissions throughout 2006 and compare O3 responses in 4 US cities: Los Angeles, Sacramento, St. Louis, and Philadelphia. We compare O3 responses between NOx-rich, O3-inhibited urban core sites and NOx-sensitive, higher O3 suburban sites and analyze projected O3 frequency distributions, which can be used to drive health effect models. We find that 2006 anthropogenic NOx and VOC emissions must be reduced by 60-70% to reach annual 4th highest (H4) maximum daily 8-h (MDA8) O3 of 75 ppb (the current US standard) in Sacramento, St. Louis, and Philadelphia, and by 80-85% to reach an H4 MDA8 of 60 ppb. Los Angeles requires larger emissions reductions and achieves an H4 MDA8 of 75 ppb with 92% reductions and 60 ppb with 97% reductions. As emissions are reduced, hourly and MDA8 frequency distributions tend toward mid-level background distributions. Mid-level O3 exposure is an important driver of O3 health impacts calculated by epidemiological models. A significant fraction (at least 48%) of summertime integrated MDA8 O3 at all sites remains after complete elimination of US anthropogenic NOx and VOC emissions, implying that mid-level O3 exposure due to background will become more important as domestic precursor emissions are controlled.

  6. 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.

  7. 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.

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

    PubMed Central

    Oh, Kwang Seok; Woo, Seong Ihl

    2011-01-01

    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. PMID:27877438

  9. 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

  10. 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.

  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. Constraints on Eurasian ship NOx emissions using OMI NO2 observations and GEOS-Chem

    NASA Astrophysics Data System (ADS)

    Vinken, Geert C. M.; Boersma, Folkert; van Donkelaar, Aaron; Zhang, Lin

    2013-04-01

    Ships emit large quantities of nitrogen oxides (NOx = NO + NO2), important precursors for ozone (O3) and particulate matter formation. Ships burn low-grade marine heavy fuel due to the limited regulations that exist for the maritime sector in international waters. Previous studies showed that global ship NOx emission inventories amount to 3.0-10.4 Tg N per year (15-30% of total NOx emissions), with most emissions close to land and affecting air quality in densely populated coastal regions. Bottom-up inventories depend on the extrapolation of a relatively small number of measurements that are often unable to capture annual emission changes and can suffer from large uncertainties. Satellites provide long-term, high-resolution retrievals that can be used to improve emission estimates. In this study we provide top-down constraints on ship NOx emissions in major European ship routes, using observed NO2 columns from the Ozone Monitoring Instrument (OMI) and NO2 columns simulated with the nested (0.5°×0.67°) version of the GEOS-Chem chemistry transport model. We use a plume-in-grid treatment of ship NOx emissions to account for in-plume chemistry in our model. We ensure consistency between the retrievals and model simulations by using the high-resolution GEOS-Chem NO2 profiles as a priori. We find evidence that ship emissions in the Mediterranean Sea are geographically misplaced by up to 150 km and biased high by a factor of 4 as compared to the most recent (EMEP) ship emission inventory. Better agreement is found over the shipping lane between Spain and the English Channel. We extend our approach and also provide constraints for major ship routes in the Red Sea and Indian Ocean. Using the full benefit of the long-term retrieval record of OMI, we present a new Eurasian ship emission inventory for the years 2005 to 2010, based on the EMEP and AMVER-ICOADS inventories, and top-down constraints from the satellite retrievals. Our work shows that satellite retrievals can

  13. 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.

  14. Investigation into the effects of vermiculite on NOx reduction and additives on sooting and exhaust infrared signature from a gas-turbine combustor. Master's thesis

    SciTech Connect

    Engel, K.R.

    1990-09-01

    An experimental investigation was conducted to determine the feasibility of using catalytic reduction of NOX emissions from a typical jet engine combustor in the test cell environment. A modified T-63 combustor in combination with an instrumented 21 foot augmentation tube containing a vermiculite catalyst was used. Several methods for containing the vermiculite were attempted. Both vermiculite and vermiculite which had been coated with thiourea were used. Up to 19% reduction in NOX concentrations was obtained using the vermiculite coated with thiourea, however the pressure loss across the catalyst bed was measured to be 36 in. H2O. The techniques used proved ineffective and unacceptable for gas turbine engine test cell applications. Tests were conducted using both Wynn's 15/590 and Catane TM (ferrocene) fuel supplements in order to determine their effectiveness for soot reduction and whether or not the exhaust plume could be changed.

  15. 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.

  16. 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.

  17. 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

    ... emission standards for NMOG+NOX described in § 86.1811-17(b)(8), credits generated in model years 2017...) in model year 2017. (c) The credit-deficit provisions 40 CFR 1037.745 apply to the NMOG+NOX...

  18. 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.

  19. Measurement of NO(x) fluxes from a tall tower in Central London, UK and comparison with emissions inventories.

    PubMed

    Lee, James D; Helfter, Carole; Purvis, Ruth M; Beevers, Sean D; Carslaw, David C; Lewis, Alastair C; Møller, Sarah J; Tremper, Anja; Vaughan, Adam; Nemitz, Eiko G

    2015-01-20

    Direct measurements of NOx concentration and flux were made from a tall tower in central London, UK as part of the Clean Air for London (ClearfLo) project. Fast time resolution (10 Hz) NO and NO2 concentrations were measured and combined with fast vertical wind measurements to provide top-down flux estimates using the eddy covariance technique. Measured NOx fluxes were usually positive and ranged from close to zero at night to 2000-8000 ng m(-2) s(-1) during the day. Peak fluxes were usually observed in the morning, coincident with the maximum traffic flow. Measurements of the NOx flux have been scaled and compared to the UK National Atmospheric Emissions Inventory (NAEI) estimate of NOx emission for the measurement footprint. The measurements are on average 80% higher than the NAEI emission inventory for all of London. Observations made in westerly airflow (from parts of London where traffic is a smaller fraction of the NOx source) showed a better agreement on average with the inventory. The observations suggest that the emissions inventory is poorest at estimating NOx when traffic is the dominant source, in this case from an easterly direction from the BT Tower. Agreement between the measurements and the London Atmospheric Emissions Inventory (LAEI) are better, due to the more explicit treatment of traffic flow by this more detailed inventory. The flux observations support previous tailpipe observations of higher NOx emitted from the London vehicle diesel fleet than is represented in the NAEI or predicted for several EURO emission control technologies. Higher-than-anticipated vehicle NOx is likely responsible for the significant discrepancies that exist in London between observed NOx and long-term NOx projections.

  20. 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.

  1. 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.

  2. 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.

  3. 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).

  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. Emission Flux Measurement Error with a Mobile DOAS System and Application to NOx Flux Observations.

    PubMed

    Wu, Fengcheng; Li, Ang; Xie, Pinhua; Chen, Hao; Hu, Zhaokun; Zhang, Qiong; Liu, Jianguo; Liu, Wenqing

    2017-01-25

    Mobile differential optical absorption spectroscopy (mobile DOAS) is an optical remote sensing method that can rapidly measure trace gas emission flux from air pollution sources (such as power plants, industrial areas, and cities) in real time. Generally, mobile DOAS is influenced by wind, drive velocity, and other factors, especially in the usage of wind field when the emission flux in a mobile DOAS system is observed. This paper presents a detailed error analysis and NOx emission with mobile DOAS system from a power plant in Shijiazhuang city, China. Comparison of the SO₂ emission flux from mobile DOAS observations with continuous emission monitoring system (CEMS) under different drive speeds and wind fields revealed that the optimal drive velocity is 30-40 km/h, and the wind field at plume height is selected when mobile DOAS observations are performed. In addition, the total errors of SO₂ and NO₂ emissions with mobile DOAS measurements are 32% and 30%, respectively, combined with the analysis of the uncertainties of column density, wind field, and drive velocity. Furthermore, the NOx emission of 0.15 ± 0.06 kg/s from the power plant is estimated, which is in good agreement with that from CEMS observations of 0.17 ± 0.07 kg/s. This study has significantly contributed to the measurement of the mobile DOAS system on emission from air pollution sources, thus improving estimation accuracy.

  6. Emission Flux Measurement Error with a Mobile DOAS System and Application to NOx Flux Observations

    PubMed Central

    Wu, Fengcheng; Li, Ang; Xie, Pinhua; Chen, Hao; Hu, Zhaokun; Zhang, Qiong; Liu, Jianguo; Liu, Wenqing

    2017-01-01

    Mobile differential optical absorption spectroscopy (mobile DOAS) is an optical remote sensing method that can rapidly measure trace gas emission flux from air pollution sources (such as power plants, industrial areas, and cities) in real time. Generally, mobile DOAS is influenced by wind, drive velocity, and other factors, especially in the usage of wind field when the emission flux in a mobile DOAS system is observed. This paper presents a detailed error analysis and NOx emission with mobile DOAS system from a power plant in Shijiazhuang city, China. Comparison of the SO2 emission flux from mobile DOAS observations with continuous emission monitoring system (CEMS) under different drive speeds and wind fields revealed that the optimal drive velocity is 30–40 km/h, and the wind field at plume height is selected when mobile DOAS observations are performed. In addition, the total errors of SO2 and NO2 emissions with mobile DOAS measurements are 32% and 30%, respectively, combined with the analysis of the uncertainties of column density, wind field, and drive velocity. Furthermore, the NOx emission of 0.15 ± 0.06 kg/s from the power plant is estimated, which is in good agreement with that from CEMS observations of 0.17 ± 0.07 kg/s. This study has significantly contributed to the measurement of the mobile DOAS system on emission from air pollution sources, thus improving estimation accuracy. PMID:28125054

  7. 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 ...

  8. 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

  9. Observational constraints on upper tropospheric NOx emissions, lifetime, and oxidative products

    NASA Astrophysics Data System (ADS)

    Nault, Benjamin Albert

    Nitrogen oxides (NOx ≡ NO + NO2) regulate tropospheric ozone (O3) production rates. In the upper troposphere (~8 -- 15 km above ground level), where O3 is an important greenhouse gas, there are few detailed measurements of NOx and its oxidation products. As a result, the chemical reactions that involve NO x are poorly characterized under the low temperature conditions in this region of the atmosphere. For the reactions that have been studied under these conditions (e.g., daytime nitric acid, or HNO3, and pernitric acid, or HO2NO2, production), the results from various experiments indicate a 20 -- 50% disagreement for the rate constants, and the other important NOx oxidation reactions (production of acyl peroxy nitrate, like PAN and PPN, and alkyl and multifunctional nitrates) have not been well characterized for the conditions characteristic of the upper troposphere. Besides the poorly understood NOx oxidation rates, recent calculations have indicated there is an important upper tropospheric NOx oxidation product (methyl peroxy nitrate, or CH3O2NO2) that has not been measured in the atmosphere. These uncertainties in the products and oxidation rate constants affect the characterization of the input of NO x from lightning. In this dissertation, I report observations obtained during two airborne field campaigns, the Deep Convective Clouds and Chemistry (DC3, May -- June, 2012) and the Studies of Emissions and Atmospheric Composition, Clouds, and Climate Coupling by Regional Surveys (SEAC4RS, August -- September, 2013) experiments, and use these observations to investigate the reaction products and rate constants for the oxidation of NOx to less reactive reservoirs. The observations focused on fresh lightning emissions in deep convective outflow, and the subsequent chemical aging of the outflow downwind. First, I present the first ambient observations of CH3O 2NO2, and recommendations on how to measure upper tropospheric in situ NO2 with minimal interferences from

  10. Increase in NOx emissions from Indian thermal power plants during 1996-2010: unit-based inventories and multisatellite observations.

    PubMed

    Lu, Zifeng; Streets, David G

    2012-07-17

    Driven by rapid economic development and growing electricity demand, NO(x) emissions (E) from the power sector in India have increased dramatically since the mid-1990s. In this study, we present the NO(x) emissions from Indian public thermal power plants for the period 1996-2010 using a unit-based methodology and compare the emission estimates with the satellite observations of NO(2) tropospheric vertical column densities (TVCDs) from four spaceborne instruments: GOME, SCIAMACHY, OMI, and GOME-2. Results show that NO(x) emissions from Indian power plants increased by at least 70% during 1996-2010. Coal-fired power plants, NO(x) emissions from which are not regulated in India, contribute ∼96% to the total power sector emissions, followed by gas-fired (∼4%) and oil-fired (<1%) ones. A number of isolated NO(2) hot spots are observed over the power plant areas, and good agreement between NO(2) TVCDs and NO(x) emissions is found for areas dominated by power plant emissions. Average NO(2) TVCDs over power plant areas were continuously increasing during the study period. We find that the ratio of ΔE/E to ΔTVCD/TVCD changed from greater than one to less than one around 2005-2008, implying that a transition of the overall NO(x) chemistry occurred over the power plant areas, which may cause significant impact on the atmospheric environment.

  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. High emission reduction performance of a novel organic-inorganic composite filters containing sepiolite mineral nanofibers.

    PubMed

    Wang, Fei; Zhang, Hui; Liang, Jinsheng; Tang, Qingguo; Li, Yanxia; Shang, Zengyao

    2017-03-02

    In this work, a new organic-inorganic composite filter was prepared. The thickness, pore size, air permeability, bursting strength and microstructure were characterized systematically, proving that coatings had regulatory effect on filters physical properties. Benefitting from the distinct coatings containing 5% sepiolite nanofibers after five times dilution, the physical properties of corresponding air filter exhibits the most favorable performance and meet the standard of air filter. When used as fuel filter, it satisfies the fuel filter standard and achieves the best performance after six times dilution. The contrast test on engine emission was taken based on auto filters coated with/without as prepared nanofibers. An obvious decrease in the emission of carbon monoxide (CO), hydrocarbons (HC) and nitrogen oxide (NOx) can be observed after installation of composite filter on vehicles. Under the high idle condition, gasoline engine emission decreased by 8.13%, 11.35% and 44.91% for CO, HC and NOx, respectively. When tested in the low idle condition, engine emission reduced by 0.43%, 1.14% and 85.67% for CO, HC and NOx, respectively. The diesel engine emissions of CO, NOx and total amount of HC and NOx decreased by 32.26%, 3.28% and 4.66%, respectively. The results illustrate the composite installation exhibits satisfactory emission reduction effect.

  13. High emission reduction performance of a novel organic-inorganic composite filters containing sepiolite mineral nanofibers

    PubMed Central

    Wang, Fei; Zhang, Hui; Liang, Jinsheng; Tang, Qingguo; Li, Yanxia; Shang, Zengyao

    2017-01-01

    In this work, a new organic-inorganic composite filter was prepared. The thickness, pore size, air permeability, bursting strength and microstructure were characterized systematically, proving that coatings had regulatory effect on filters physical properties. Benefitting from the distinct coatings containing 5% sepiolite nanofibers after five times dilution, the physical properties of corresponding air filter exhibits the most favorable performance and meet the standard of air filter. When used as fuel filter, it satisfies the fuel filter standard and achieves the best performance after six times dilution. The contrast test on engine emission was taken based on auto filters coated with/without as prepared nanofibers. An obvious decrease in the emission of carbon monoxide (CO), hydrocarbons (HC) and nitrogen oxide (NOx) can be observed after installation of composite filter on vehicles. Under the high idle condition, gasoline engine emission decreased by 8.13%, 11.35% and 44.91% for CO, HC and NOx, respectively. When tested in the low idle condition, engine emission reduced by 0.43%, 1.14% and 85.67% for CO, HC and NOx, respectively. The diesel engine emissions of CO, NOx and total amount of HC and NOx decreased by 32.26%, 3.28% and 4.66%, respectively. The results illustrate the composite installation exhibits satisfactory emission reduction effect. PMID:28252034

  14. High emission reduction performance of a novel organic-inorganic composite filters containing sepiolite mineral nanofibers

    NASA Astrophysics Data System (ADS)

    Wang, Fei; Zhang, Hui; Liang, Jinsheng; Tang, Qingguo; Li, Yanxia; Shang, Zengyao

    2017-03-01

    In this work, a new organic-inorganic composite filter was prepared. The thickness, pore size, air permeability, bursting strength and microstructure were characterized systematically, proving that coatings had regulatory effect on filters physical properties. Benefitting from the distinct coatings containing 5% sepiolite nanofibers after five times dilution, the physical properties of corresponding air filter exhibits the most favorable performance and meet the standard of air filter. When used as fuel filter, it satisfies the fuel filter standard and achieves the best performance after six times dilution. The contrast test on engine emission was taken based on auto filters coated with/without as prepared nanofibers. An obvious decrease in the emission of carbon monoxide (CO), hydrocarbons (HC) and nitrogen oxide (NOx) can be observed after installation of composite filter on vehicles. Under the high idle condition, gasoline engine emission decreased by 8.13%, 11.35% and 44.91% for CO, HC and NOx, respectively. When tested in the low idle condition, engine emission reduced by 0.43%, 1.14% and 85.67% for CO, HC and NOx, respectively. The diesel engine emissions of CO, NOx and total amount of HC and NOx decreased by 32.26%, 3.28% and 4.66%, respectively. The results illustrate the composite installation exhibits satisfactory emission reduction effect.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. Characteristics of on-road NOx emissions from Euro 6 light-duty diesel vehicles using a portable emissions measurement system.

    PubMed

    Kwon, Sangil; Park, Yonghee; Park, Junhong; Kim, Jeongsoo; Choi, Kwang-Ho; Cha, Jun-Seok

    2017-01-15

    This paper presents the on-road nitrogen oxides (NOx) emissions measurements from Euro 6 light-duty diesel vehicles using a portable emissions measurement system on the predesigned test routes in the metropolitan area of Seoul, Korea. Six diesel vehicles were tested and the NOx emissions results were analyzed according to the driving routes, driving conditions, data analysis methods, and ambient temperatures. Total NOx emissions for route 1, which has higher driving severity than route 2, differed by -4-60% from those for route 2. The NOx emissions when the air conditioner (AC) was used were higher by 68% and 85%, on average, for routes 1 and 2, respectively, compared to when the AC was not used. The analytical results for NOx emissions by the moving averaging window method were higher by 2-31% compared to the power binning method. NOx emissions at lower ambient temperatures (0-5°C) were higher by 82-192% compared to those at higher ambient temperatures (15-20°C). This result shows that performance improvements of exhaust gas recirculation and the NOx after-treatment system will be needed at lower ambient temperatures.

  1. 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

  2. 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.

  3. 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.

  4. Decadal changes in global surface NOx emissions from multi-constituent satellite data assimilation

    NASA Astrophysics Data System (ADS)

    Miyazaki, Kazuyuki; Eskes, Henk; Sudo, Kengo; Folkert Boersma, K.; Bowman, Kevin; Kanaya, Yugo

    2017-01-01

    Global surface emissions of nitrogen oxides (NOx) over a 10-year period (2005-2014) are estimated from an assimilation of multiple satellite data sets: tropospheric NO2 columns from Ozone Monitoring Instrument (OMI), Global Ozone Monitoring Experiment-2 (GOME-2), and Scanning Imaging Absorption Spectrometer for Atmospheric Chartography (SCIAMACHY), O3 profiles from Tropospheric Emission Spectrometer (TES), CO profiles from Measurement of Pollution in the Troposphere (MOPITT), and O3 and HNO3 profiles from Microwave Limb Sounder (MLS) using an ensemble Kalman filter technique. Chemical concentrations of various species and emission sources of several precursors are simultaneously optimized. This is expected to improve the emission inversion because the emission estimates are influenced by biases in the modelled tropospheric chemistry, which can be partly corrected by also optimizing the concentrations. We present detailed distributions of the estimated emission distributions for all major regions, the diurnal and seasonal variability, and the evolution of these emissions over the 10-year period. The estimated regional total emissions show a strong positive trend over India (+29 % decade-1), China (+26 % decade-1), and the Middle East (+20 % decade-1), and a negative trend over the USA (-38 % decade-1), southern Africa (-8.2 % decade-1), and western Europe (-8.8 % decade-1). The negative trends in the USA and western Europe are larger during 2005-2010 relative to 2011-2014, whereas the trend in China becomes negative after 2011. The data assimilation also suggests a large uncertainty in anthropogenic and fire-related emission factors and an important underestimation of soil NOx sources in the emission inventories. Despite the large trends observed for individual regions, the global total emission is almost constant between 2005 (47.9 Tg N yr-1) and 2014 (47.5 Tg N yr-1).

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. Verification of NOx emission inventory over South Korea using sectoral activity data and satellite observation of NO2 vertical column densities

    NASA Astrophysics Data System (ADS)

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

    2013-10-01

    In this study, the emission inventories of NOx, which is a major air pollutant of South Korea were compared and analyzed. The two bottom-up emission inventories, Clean Air Policy Support System (CAPSS) and Regional Emission inventory in ASia (REAS), which are the latest emission inventories about the air pollutant emissions about South Korea were compared to find out the trend of NOx emission during 1996-2005. Also, these two emission inventories were compared with the top down NOx emissions estimated from satellite observations to validate the amount of NOx emitted from South Korea. The total NOx emission trends, sectoral and regional comparisons were carried out. The trend of the top down estimated NOx emission was similar to CAPSS and REAS. However, the magnitudes of the top down estimated NOx emission were usually closer to those of CAPSS than those of REAS. The NOx emissions from transportation sector of REAS were larger than that of CAPSS, and this corresponded to the difference of total amount of NOx emission between CAPSS and REAS. By comparing the differences of the ratios of the vehicle kilometers traveled (VKT) and emission factors (EFs), it was identified that most of the difference between CAPSS and REAS was due to these factors for diesel vehicles in REAS. Implications of this higher VKT values in REAS were discussed.

  11. 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

  12. 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

  13. 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.

  14. 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

  15. 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.

  16. Public health impacts of excess NOx emissions from Volkswagen diesel passenger vehicles in Germany

    NASA Astrophysics Data System (ADS)

    Chossière, Guillaume P.; Malina, Robert; Ashok, Akshay; Dedoussi, Irene C.; Eastham, Sebastian D.; Speth, Raymond L.; Barrett, Steven R. H.

    2017-03-01

    In September 2015, the Volkswagen Group (VW) admitted the use of ‘defeat devices’ designed to lower emissions measured during VW vehicle testing for regulatory purposes. Globally, 11 million cars sold between 2008 and 2015 are affected, including about 2.6 million in Germany. On-road emissions tests have yielded mean on-road NOx emissions for these cars of 0.85 g km‑1, over four times the applicable European limit of 0.18 g km‑1. This study estimates the human health impacts and costs associated with excess emissions from VW cars driven in Germany. A distribution of on-road emissions factors is derived from existing measurements and combined with sales data and a vehicle fleet model to estimate total excess NOx emissions. These emissions are distributed on a 25 by 28 km grid covering Europe, using the German Federal Environmental Protection Agency’s (UBA) estimate of the spatial distribution of NOx emissions from passenger cars in Germany. We use the GEOS-Chem chemistry-transport model to predict the corresponding increase in population exposure to fine particulate matter and ozone in the European Union, Switzerland, and Norway, and a set of concentration-response functions to estimate mortality outcomes in terms of early deaths and of life-years lost. Integrated over the sales period (2008–2015), we estimate median mortality impacts from VW excess emissions in Germany to be 1200 premature deaths in Europe, corresponding to 13 000 life-years lost and 1.9 billion EUR in costs associated with life-years lost. Approximately 60% of mortality costs occur outside Germany. For the current fleet, we estimate that if on-road emissions for all affected VW vehicles in Germany are reduced to the applicable European emission standard by the end of 2017, this would avert 29 000 life-years lost and 4.1 billion 2015 EUR in health costs (median estimates) relative to a counterfactual case with no recall.

  17. Quantification of hourly variability in NO(x) emissions for baseload coal-fired power plants.

    PubMed

    Abdel-Aziz, Amr; Frey, H Christopher

    2003-11-01

    The objectives of this paper are to (1) quantify variability in hourly utility oxides of nitrogen (NO(x)) emission factors, activity factors, and total emissions; (2) investigate the autocorrelation structure and evaluate cyclic effects at short and long scales of the time series of total hourly emissions; (3) compare emissions for the ozone (O3) season versus the entire year to identify seasonal differences, if any; and (4) evaluate interannual variability. Continuous emissions monitoring data were analyzed for 1995 and 1998 for 32 units from nine baseload power plants in the Charlotte, NC, airshed. Unit emissions have a strong 24-hr cycle attributable primarily to the capacity factor. Typical ranges of the coefficient of variation for emissions at a given hour of the day were from 0.2 to 0.45. Little difference was found when comparing weekend emissions with the entire week or when comparing the O3 season with the entire year. There were substantial differences in the mean and standard deviation of emissions when comparing 1995 and 1998 data, indicative of the effect of retrofits of control technology during the intervening time. The wide range of variability and its autocorrelation should be accounted for when developing probabilistic utility emission inventories for analysis of near-term future episodes.

  18. New Heterogeneous Catalysts for the Selective Reduction of NOx under Lean Conditions. Final Report

    SciTech Connect

    Amiridis, M. D.

    2004-05-31

    The original goal of this program was the identification and design of new noble-metal-based catalysts for the selective catalytic reduction of nitric oxide by hydrocarbons under excess oxygen (i.e., ''lean'') conditions (HC-SCR). Work conducted in the first funding cycle of this award (i.e., 1997-2000) was successful in allowing us to develop an understanding of the fundamental surface chemistry taking place during the adsorption and reaction of nitrogen oxides and propylene on the surface of supported noble metal catalysts. Both experimental results collected in our own group as well as molecular simulation results published by Professor Neurock suggested that in order to improve the performance of the Pt catalysts--in terms of the nitrogen selectivity and the temperature window of operation-- it was necessary to introduce a second metal. However, synthesizing such catalysts with the metals of interest (i.e., Pt-Au, Pt-Ru, Pt-Rh, etc.) with some degree of control of the structure and composition of the resulting supported metal particles is in itself a research challenge. Consequently, the bulk of our efforts during the second funding cycle of this award (covered by this report) was shifted to the use of organometallic cluster precursors for the synthesis on novel bimetallic catalysts. During this time we have also continued to maintain an interest in NOx abatement, but have redirected our efforts from the HC-SCR process to the more promising from a commercial standpoint NOx Storage Reduction (NSR) approach.

  19. Evaluation of Corona Reactors of Several Geometries for a Plasma Assisted Nitrogen Oxide Emission Reduction Device

    SciTech Connect

    Herling, Darrell R.; Smith, Monty R.; Hemingway, Mark D.; Goulette, David; Silvis, Thomas W.

    2000-08-09

    Proposed vehicle emissions regulations for the near future have prompted automotive manufactures and component suppliers to focus heavily on developing more efficient exhaust aftertreatment devices to lower emissions from spark and compression ignition engines. One of the primary pollutants from lean-burn engines, especially from diesels, are oxides of nitrogen (NOx). Current three-way catalytic converters will not have adequate performance to meet future emission reduction requirements. Therefore, there is a need for researchers and engineers to develop efficient exhaust aftertreatment devices that will reduce NOx emissions from lean-burn engines. These devices must have very high conversion of NOx gases, be unaffected by exhaust-gas impurity such as sulfur, and have minimal impact on vehicle operations and fuel economy. An effective technology for NOx control that is currently receiving a lot of attention is a non-thermal plasma system. This system is comprised of a two-stage corona generation device (plasma reactor) and reduction catalyst that reduces nitric oxide and nitrogen dioxide emissions to nitrogen.

  20. 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.

  1. Evaluating real-world CO2 and NOX emissions for public transit buses using a remote wireless on-board diagnostic (OBD) approach.

    PubMed

    Yang, Liuhanzi; Zhang, Shaojun; Wu, Ye; Chen, Qizheng; Niu, Tianlin; Huang, Xu; Zhang, Shida; Zhang, Liangjun; Zhou, Yu; Hao, Jiming

    2016-11-01

    The challenge to mitigate real-world emissions from vehicles calls for powerful in-use compliance supervision. The remote on-board diagnostic (OBD) approach, with wireless data communications, is one of the promising next-generation monitoring methods. We collected second-by-second profiles of carbon dioxide (CO2) and nitrogen oxides (NOX) emissions, driving conditions and engine performance for three conventional diesel and three hybrid diesel buses participating in a remote OBD pilot program in Nanjing, China. Our results showed that the average CO2 emissions for conventional diesel and hybrid diesel buses were 816 ± 83 g km(-1) and 627 ± 54 g km(-1), respectively, under a typical driving pattern. An operating mode binning analysis indicated that CO2 emissions reduction by series-parallel hybrid technology was largely because of the significant benefits of the technology under the modes of low speed and low power demand. However, significantly higher CO2 emissions were observed for conventional diesel buses during rush hours, higher than 1200 g km(-1). The OBD data suggested no improvement in NOX emission reduction for hybrid buses compared with conventional buses; both were approximately 12 g km(-1) because of poor performance of the selective catalyst reduction (SCR) systems in the real world. Speed-dependent functions for real-world CO2 and NOX emissions were also constructed. The CO2 emissions of hybrid buses were much less sensitive to the average speed than conventional buses. If the average speed decreased from 20 km h(-1) to 10 km h(-1), the estimated CO2 emission factor for conventional buses would be increased by 34%. Such a change in speed would increase NOX emissions for conventional and hybrid buses by 38% and 56%, respectively. This paper demonstrates the useful features of the remote OBD system and can inform policy makers how to take advantage of these features in monitoring in-use vehicles.

  2. 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.

  3. Does the New European Driving Cycle (NEDC) really fail to capture the NOX emissions of diesel cars in Europe?

    PubMed

    Degraeuwe, Bart; Weiss, Martin

    2017-03-01

    Tests with Portable Emissions Measurement Systems (PEMS) have demonstrated that diesel cars emit several times more NOX on the road than during certification on the New European Driving Cycle (NEDC). Policy makers and scientists have attributed the discrepancy to the unrealistically low dynamics and the narrow temperature range of NEDC testing. Although widely accepted, this assumption was never been put under scientific scrutiny. Here, we demonstrate that the narrow NEDC test conditions explain only a small part of the elevated on-road NOX emissions of diesel cars. For seven Euro 4-6 diesel cars, we filter from on-road driving those events that match the NEDC conditions in instantaneous speed, acceleration, CO2 emissions, and ambient temperature. The resulting on-road NOX emissions exceed by 206% (median) those measured on the NEDC, whereas the NOX emissions of all unfiltered on-road measurements exceed the NEDC emissions by 266% (median). Moreover, when applying the same filtering of on-road data to two other driving cycles (WLTP and CADC), the resulting on-road NOX emissions exceed by only 13% (median) those measured over the respective cycles. This result demonstrates that our filtering method is accurate and robust. If neither the low dynamics nor the limited temperature range of NEDC testing can explain the elevated NOX emissions of diesel cars, emissions control strategies used during NEDC testing must be inactive or modulated on the road, even if vehicles are driven under certification-like conditions. This points to defeat strategies that warrant further investigations by type-approval authorities and, in turn, limitations in the enforcement of the European vehicle emissions legislation by EU Member States. We suggest applying our method as a simple yet effective tool to screen and select vehicles for in-depth analysis by the competent certification authorities.

  4. 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.

  5. 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.

  6. 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

  7. Emission Reduction of Fuel-Staged Aircraft Engine Combustor Using an Additional Premixed Fuel Nozzle.

    PubMed

    Yamamoto, Takeshi; Shimodaira, Kazuo; Yoshida, Seiji; Kurosawa, Yoji

    2013-03-01

    The Japan Aerospace Exploration Agency (JAXA) is conducting research and development on aircraft engine technologies to reduce environmental impact for the Technology Development Project for Clean Engines (TechCLEAN). As a part of the project, combustion technologies have been developed with an aggressive target that is an 80% reduction over the NOx threshold of the International Civil Aviation Organization (ICAO) Committee on Aviation Environmental Protection (CAEP)/4 standard. A staged fuel nozzle with a pilot mixer and a main mixer was developed and tested using a single-sector combustor under the target engine's landing and takeoff (LTO) cycle conditions with a rated output of 40 kN and an overall pressure ratio of 25.8. The test results showed a 77% reduction over the CAEP/4 NOx standard. However, the reduction in smoke at thrust conditions higher than the 30% MTO condition and of CO emission at thrust conditions lower than the 85% MTO condition are necessary. In the present study, an additional fuel burner was designed and tested with the staged fuel nozzle in a single-sector combustor to control emissions. The test results show that the combustor enables an 82% reduction in NOx emissions relative to the ICAO CAEP/4 standard and a drastic reduction in smoke and CO emissions.

  8. Estimates of Emissions and Chemical Lifetimes of NOx from Point Sources using OMI Retrievals

    NASA Astrophysics Data System (ADS)

    de Foy, B.

    2014-12-01

    We use three different methods to estimate emissions of NOx from large point sources based on OMI retrievals. The results are evaluated against data from the Continuous Emission Monitoring System (CEMS). The methods tested are: 1. Simple box model, 2. Two-dimensional Gaussian fit and 3. Exponentially-Modified Gaussian Fit. The sensitivity of the results to the plume speed and wind direction was explored by considering different ways of estimating these from wind measurements. The accuracy of the emissions estimates compared with the CEMS data was found to be variable from site to site. Furthermore, lifetimes obtained from some of the methods were found to be very short and are thought to be more representative of plume transport than of chemical transformation. We explore the strengths and weaknesses of the methods and consider avenues for improved estimates.

  9. NOx emission constraints on high-temperature processes. Final report, April 1988-November 1990

    SciTech Connect

    Brown, R.A.; Mason, H.B.; Nicholson, J.A.; Okoh, C.I.

    1990-11-01

    Current and emerging NOx emission regulations were reviewed to identify possible constraints on high-performance burner application in industrial furnaces. Industrial furnace regulations were evaluated for new and existing sources in air quality attainment and nonattainment areas. Processes emphasized were ferrous and nonferrous metals heating and heat-treating furnaces, glass melting furnaces, and mineral kilns. Regulation of best available control technology (BACT) for new sources is projected to impact process furnaces the most. Metal reheating furnaces, glass melting furnaces, and kilns will be the most susceptible to BACT. Nonferrous melting forging furnace and soaking pits will not be seriously constrained by BACT.

  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. 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.

  12. 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.

  13. 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.

  14. Modeling the effects of changes in New Source Review on national SO{sub 2} and NOx emissions from electricity-generating units

    SciTech Connect

    David A. Evans; Benjamin F. Hobbs; Craig Oren; Karen L. Palmer

    2007-03-15

    The Clean Air Act establishes New Source Review (NSR) programs that apply to the construction or modification of major stationary emissions sources. In 2002 and 2003, the U.S. Environmental Protection Agency revised its rules to narrow the applicability of NSR to facility renovations. Congress then mandated a National Research Council study of the effects of the rules. An electricity-sector model - the Integrated Planning Model (IPM) - was used to explore the possible effects of the equipment replacement provision (ERP), the principal NSR change that was to affect the power-generation industry. The studies focused in particular on coal-fired electricity generating units, EGUs, for two reasons. First, coal-fired EGUs are important contributors of these pollutants, accounting for approximately 70 and 20% of nations SO{sub 2} and NOx emissions in 2004, respectively. Second, the shares of total capacity of large coal-fired EGUs that lack flue-gas desulfurization to control SO{sub 2} and selective catalytic reduction to reduce NOx emissions are 62 and 63% respectively. Although the analysis cannot predict effects on local emissions, assuming that the Clean Air Interstate Rule (CAIR) is implemented, we find that stringent enforcement of the previous NSR rules would likely lead to no or limited decreases in national emissions compared to policies such as ERP. Our results indicate that tighter emissions caps could achieve further decreases in national emissions more cost-effectively than NSR programs. 15 refs., 3 figs., 1 tab.

  15. 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.

  16. Implications of near-term coal power plant retirement for SO2 and NOX and life cycle GHG emissions.

    PubMed

    Venkatesh, Aranya; Jaramillo, Paulina; Griffin, W Michael; Matthews, H Scott

    2012-09-18

    Regulations monitoring SO(2), NO(X), mercury, and other metal emissions in the U.S. will likely result in coal plant retirement in the near-term. Life cycle assessment studies have previously estimated the environmental benefits of displacing coal with natural gas for electricity generation, by comparing systems that consist of individual natural gas and coal power plants. However, such system comparisons may not be appropriate to analyze impacts of coal plant retirement in existing power fleets. To meet this limitation, simplified economic dispatch models for PJM, MISO, and ERCOT regions are developed in this study to examine changes in regional power plant dispatch that occur when coal power plants are retired. These models estimate the order in which existing power plants are dispatched to meet electricity demand based on short-run marginal costs, with cheaper plants being dispatched first. Five scenarios of coal plant retirement are considered: retiring top CO(2) emitters, top NO(X) emitters, top SO(2) emitters, small and inefficient plants, and old and inefficient plants. Changes in fuel use, life cycle greenhouse gas emissions (including uncertainty), and SO(2) and NO(X) emissions are estimated. Life cycle GHG emissions were found to decrease by less than 4% in almost all scenarios modeled. In addition, changes in marginal damage costs due to SO(2), and NO(X) emissions are estimated using the county level marginal damage costs reported in the Air Pollution Emissions Experiments and Policy (APEEP) model, which are a proxy for measuring regional impacts of SO(2) and NO(X) emissions. Results suggest that location specific parameters should be considered within environmental policy frameworks targeting coal plant retirement, to account for regional variability in the benefits of reducing the impact of SO(2) and NO(X) emissions.

  17. 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.

  18. 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.

  19. 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

  20. 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.

  1. Ozone trends across the United States over a period of decreasing NOx and VOC emissions.

    PubMed

    Simon, Heather; Reff, Adam; Wells, Benjamin; Xing, Jia; Frank, Neil

    2015-01-06

    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, and at the upper end of the ozone distribution. Conversely, increasing ozone trends generally occur in the winter, in more urbanized areas, and at the lower end of the ozone distribution. The 95(th) percentile ozone concentrations decreased at urban, suburban, and rural monitors by 1-2 ppb/yr in the summer and 0.5-1 ppb/yr in the winter. In the summer, there are both increasing and decreasing trends in fifth percentile ozone concentrations of less than 0.5 ppb/yr at urban and suburban monitors, while fifth percentile ozone concentrations at rural monitors decreased by up to 1 ppb/yr. In the winter, fifth percentile ozone concentrations generally increased by 0.1-1 ppb/yr. These results demonstrate the large scale success of U.S. control strategies targeted at decreasing peak ozone concentrations. In addition, they indicate that as anthropogenic NOx emissions have decreased, the ozone distribution has been compressed, leading to less spatial and temporal variability.

  2. Multi-annual changes of NOx emissions in megacity regions: nonlinear trend analysis of satellite measurement based estimates

    NASA Astrophysics Data System (ADS)

    Konovalov, I. B.; Beekmann, M.; Richter, A.; Burrows, J. P.; Hilboll, A.

    2010-04-01

    Hazardous impact of air pollutant emissions from megacities on atmospheric composition on regional and global scales is currently an important issue in atmospheric research. However, the quantification of emissions and related effects is frequently a difficult task, especially in the case of developing countries, due to the lack of reliable data and information. This study examines possibilities to retrieve multi-annual NOx emissions changes in megacity regions from satellite measurements of nitrogen dioxide and to quantify them in terms of linear and nonlinear trends. By combining the retrievals of the GOME and SCIAMACHY satellite instrument data with simulations performed by the CHIMERE chemistry transport model, we obtain the time series of NOx emission estimates for the 12 largest urban agglomerations in Europe and the Middle East in the period from 1996 to 2008. We employ then a novel method allowing estimation of a nonlinear trend in a noisy time series of an observed variable. The method is based on the probabilistic approach and the use of artificial neural networks; it does not involve any quantitative a priori assumptions. As a result, statistically significant nonlinearities in the estimated NOx emission trends are detected in 5 megacities (Bagdad, Madrid, Milan, Moscow and Paris). Statistically significant upward linear trends are detected in Istanbul and Tehran, while downward linear trends are revealed in Berlin, London and the Ruhr agglomeration. The presence of nonlinearities in NOx emission changes in Milan, Paris and Madrid is confirmed by comparison of simulated NOx concentrations with independent air quality monitoring data. A good quantitative agreement between the linear trends in the simulated and measured near surface NOx concentrations is found in London.

  3. Multi-annual changes of NOx emissions in megacity regions: nonlinear trend analysis of satellite measurement based estimates

    NASA Astrophysics Data System (ADS)

    Konovalov, I. B.; Beekmann, M.; Richter, A.; Burrows, J. P.; Hilboll, A.

    2010-09-01

    Hazardous impact of air pollutant emissions from megacities on atmospheric composition on regional and global scales is currently an important issue in atmospheric research. However, the quantification of emissions and related effects is frequently a difficult task, especially in the case of developing countries, due to the lack of reliable data and information. This study examines possibilities to retrieve multi-annual NOx emissions changes in megacity regions from satellite measurements of nitrogen dioxide and to quantify them in terms of linear and nonlinear trends. By combining the retrievals of the GOME and SCIAMACHY satellite instrument data with simulations performed by the CHIMERE chemistry transport model, we obtain the time series of NOx emission estimates for the 12 largest urban agglomerations in Europe and the Middle East in the period from 1996 to 2008. We employ then a novel method allowing estimation of a nonlinear trend in a noisy time series of an observed variable. The method is based on the probabilistic approach and the use of artificial neural networks; it does not involve any quantitative a priori assumptions. As a result, statistically significant nonlinearities in the estimated NOx emission trends are detected in 5 megacities (Bagdad, Madrid, Milan, Moscow and Paris). Statistically significant upward linear trends are detected in Istanbul and Tehran, while downward linear trends are revealed in Berlin, London and the Ruhr agglomeration. The presence of nonlinearities in NOx emission changes in Milan, Paris and Madrid is confirmed by comparison of simulated NOx concentrations with independent air quality monitoring data. A good quantitative agreement between the linear trends in the simulated and measured near surface NOx concentrations is found in London.

  4. 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.

  5. Modeling Air Pollution in Beijing: Emission Reduction vs. Meteorological Influence

    NASA Astrophysics Data System (ADS)

    Risse, Eicke-Alexander; Hao, Nan; Trautmann, Thomas

    2016-08-01

    This case study uses the Chemical Transport Model WRF-Chem to simulate and measure the efficiency of temporal large-scale emission reductions under different meteorological conditions. The Nov. 2014 Asian Pacific Economic Cooperation (APEC) summit provides a unique opportunity for this study due to the extraordinarily good and well-measured air quality which is believed to be induced by intense emission- reduction measures by the Chinese government. Four cases are simulated to inter-compare between favorable und unfavorablemeteorological conditions (in terms of air quality) as well as reduced and non-reduced emissions. Key variables of the simulation results are evaluated against AERONET measurements of Aerosol Optical Depth (AOD) and air-quality measurements by the Chinese Ministry of Environment (CME). The inter-comparison is then performed on time- and volume-averaged total concentrations of the key variables Nitrogenous Oxide (NOx) and Particulate Matter (PM2.5 and PM10).The simulation settings and some important facts about the model are shown in table 1.

  6. 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

  7. 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.

  8. NOx removal from vehicle emissions by functionality surface of asphalt road.

    PubMed

    Chen, Meng; Liu, Yanhua

    2010-02-15

    This paper reported the potential of heterogeneous photocatalysis as an advanced oxidation technology for NO(x) removal from vehicle emissions by using TiO(2) as a photocatalyst immobilized on the surface of asphalt road. Based on asphalt road material porous characteristic, we utilized permeability technology to make asphalt nano-TiO(2) to be environmental protection materials. And then using scanning electron microscope, we observed the penetrating effect of TiO(2). The effect of surface friction, humidity and light intensity on NO(x) removal had been systematically investigated by the use of TiO(2) immobilized on the surface of asphalt road as photocatalytic environmental protection materials. In addition, the decontaminating effect was tested by contrast test in TiO(2) spraying section with non-spraying section, while the productions were used in road environment. Results of experiment revealed that decontaminating rate of the productions ranged from 6% to 12% this kind of photochemical catalysis environmental protection material has good environment purification function.

  9. Method for control of NOx emission from combustors using fuel dilution

    DOEpatents

    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.

  10. 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.

  11. Reduction of Fe(III) chelated with citrate in an NOx scrubber solution by Enterococcus sp. FR-3.

    PubMed

    Li, Wei; Liu, Nan; Cai, Ling-Lin; Jiang, Jin-Lin; Chen, Jian-Meng

    2011-02-01

    Biological reduction of Fe(III) to Fe(II) is a key step in nitrogen oxide (NO(x)) removal by the integrated chemical absorption-biological reduction process. NO(x) removal efficiency strongly depends on the concentration of Fe(II) in the scrubbing liquid. In this study, a newly isolated strain, Enterococcus sp. FR-3, was used to reduce Fe(III) chelated with citrate to Fe(II). Strain FR-3 reduced citrate-chelated Fe(III) with an efficiency of up to 86.9% and an average reduction rate of 0.21 mM h(-1). SO(4)(2-) was not inhibitory whereas NO(2)(-) and SO(3)(2-) inhibited cell growth and thus affected Fe(III) reduction. Models based on the Logistic equation were used to describe the relationship between growth and Fe(III) reduction. These findings provide some useful data for Fe(III) reduction, scrubber solution regeneration and NO(x) removal process design.

  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 PAGES

    Mráček, David; Koci, Petr; Choi, Jae -Soon; ...

    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. 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.

  14. 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.

  15. 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.

  16. Vortex combustor for low NOX emissions when burning lean premixed high hydrogen content fuel

    SciTech Connect

    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.

  17. 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.

  18. Stratospheric cruise emission reduction program

    NASA Technical Reports Server (NTRS)

    Diehl, L. A.; Reck, G. M.; Marek, C. J.; Szaniszlo, A. J.

    1977-01-01

    A recently implemented NASA effort specifically aimed at reducing cruise oxides of nitrogen from high-altitude aircraft is discussed. The desired emission levels and the combustor technology required to achieve them are discussed. A brief overview of the SCERP operating plan is given. Lean premixed-prevaporized combustion and some of the potential difficulties that are associated with applying this technique to gas turbine combustors are examined. Base technology was developed in several key areas. These fundamental studies are viewed as a requirement for successful implementation of the lean premixed combustion technique.

  19. 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.

  20. Regeneration and sulfur poisoning behavior of In/H-BEA catalyst for NOx reduction by CH4

    NASA Astrophysics Data System (ADS)

    Pan, Hua; Jian, Yanfei; Yu, Yanke; He, Chi; Shen, Zhenxing; Liu, Hongxia

    2017-04-01

    Sulfur poisoning and regeneration behavior of In/H-BEA catalyst were carried out in NOx reduction by CH4. In/H-BEA catalyst exhibited a poor resistance to sulfur dioxide after addition of 200 ppm SO2 and 10 vol.% H2O into NO reduction with CH4 at 450 °C for 45 h. Sulfur poisoning of In/H-BEA was attributed to the inhibition of NOx adsorption on Brønsted acid sites, suppression of reaction intermediates generation on the active sites, and the formation of surface sulfate species. The formation of surface sulfate reduced the availability of surface active sites, blocked the pore structure and decreased the surface area of catalyst. These changes in chemical and textural properties resulted in a severe loss in the activity of sulfated In/H-BEA catalyst for NO reduction with CH4. H2 reduction is a promising technology for regeneration of In/H-BEA deactivated by SO2 for removing NOx from lean-burn and diesel exhausts. Indium sulfate could be reduced by H2 to InO+ with In2O3 and In(OH)2+ as the intermediates. The optimal parameters of H2 reduction was regeneration temperature of 400 °C and regeneration time of 60 min which completely recovered the catalytic activity of In/H-BEA.

  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. 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

  3. 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

  4. 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

  5. 180 MW demonstration of advanced tangentially-fired combustion techniques for the reduction of nitrogen oxide (NO sub x ) emissions from coal-fired boilers

    SciTech Connect

    Not Available

    1991-01-01

    ABB CE's Low NOx Bulk Furnace Staging (LNBFS) System and Low NOx Concentric Firing System (LNCFS) are demonstrated in stepwise fashion. These systems incorporate the concept of advanced overfire air (AOFA), clustered coal nozzles, and offset air. A complete description of the installed technologies is provided in the following section. The primary objective of the Plant Lansing Smith demonstration is to determine the long-term effects of commercially available tangentially-fired low NOx combustion technologies on NOx emissions and boiler performance. Short-term tests of each technology are also being performed to provide engineering information about emissions and performance trends. A target of achieving fifty percent NOx reduction using combustion modifications has been established for the project.

  6. 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

  7. 500 MW demonstration of advanced wall-fired combustion techniques for the reduction of nitrogen oxide emissions from coal-fired boilers

    SciTech Connect

    Sorge, J.N.; Menzies, B.; Smouse, S.M.; Stallings, J.W.

    1995-09-01

    Technology project demonstrating advanced wall-fired combustion techniques for the reduction of nitrogen oxide NOx emissions from coal-fired boilers. The primary objective of the demonstration is to determine the long-term NOx reduction performance of advanced overfire air (AOFA), low NOx burners (LNB), and advanced digital control/optimization methodologies applied in a stepwise fashion to a 500 MW boiler. The focus of this paper is to report (1) on the installation of three on-line carbon-in-ash monitors and (2) the design and results to date from the advanced digital control/optimization phase of the project.

  8. 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

  9. 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.

  10. 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.

  11. 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.

    2017-03-01

    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.

  12. 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.

  13. 500 MW demonstration of advanced wall-fired combustion techniques for the reduction of nitrogen oxide (NO{sub x}) emissions from coal-fired boilers. Technical progress report, second quarter 1994, April 1994--June 1994

    SciTech Connect

    1995-09-01

    This quarterly report discusses the technical progress of an Innovative Clean Coal Technology (ICCT) demonstration of advanced wall-fired combustion techniques for the reduction of nitrogen oxide (NOx) emissions from coal-fired boilers. The project is being conducted at Georgia Power Company`s Plant Hammond Unit 4 located near Rome, Georgia. The primary goal of this project is the characterization of the low NOx combustion equipment through the collection and analysis of long-term emissions data. A target of achieving fifty percent NOx reduction using combustion modifications has been established for the project. The project provides a stepwise retrofit of an advanced overfire air (AOFA) system followed by low NOx burners (LNB). During each test phase of the project, diagnostic, performance, long-term, and verification testing will be performed. These tests are used to quantify the NOx reductions of each technology and evaluate the effects of those reductions on other combustion parameters. Results are described.

  14. 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.

  15. 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.

  16. 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.

  17. Latitudinal variation of the effect of aviation NOx emissions on atmospheric ozone and methane and related climate metrics

    NASA Astrophysics Data System (ADS)

    Köhler, M. O.; Rädel, G.; Shine, K. P.; Rogers, H. L.; Pyle, J. A.

    2013-01-01

    We evaluate the response to regional and latitudinal changes in aircraft NOx emissions using several climate metrics (radiative forcing (RF), Global Warming Potential (GWP), Global Temperature change Potential (GTP)). Global chemistry transport model integrations were performed with sustained perturbations in regional aircraft and aircraft-like NOx emissions. The RF due to the resulting ozone and methane changes is then calculated. We investigate the impact of emission changes for specific geographical regions (approximating to USA, Europe, India and China) and cruise altitude emission changes in discrete latitude bands covering both hemispheres. We find that lower latitude emission changes (per Tg N) cause ozone and methane RFs that are about a factor of 6 larger than those from higher latitude emission changes. The net RF is positive for all experiments. The meridional extent of the RF is larger for low latitude emissions. GWPs for all emission changes are positive, with tropical emissions having the largest values; the sign of the GTP depends on the choice of time horizon.

  18. 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.

  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. Satellite NO2 retrievals suggest China has exceeded its NOx reduction goals from the twelfth Five-Year Plan

    NASA Astrophysics Data System (ADS)

    de Foy, Benjamin; Lu, Zifeng; Streets, David G.

    2016-10-01

    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.

  1. A case study of the relative effects of power plant nitrogen oxides and sulfur dioxide emission reductions on atmospheric nitrogen deposition.

    PubMed

    Vijayaraghavan, Krish; Seigneur, Christian; Bronson, Rochelle; Chen, Shu-Yun; Karamchandani, Prakash; Walters, Justin T; Jansen, John J; Brandmeyer, Jo Ellen; Knipping, Eladio M

    2010-03-01

    The contrasting effects of point source nitrogen oxides (NOx) and sulfur dioxide (SO2) air emission reductions on regional atmospheric nitrogen deposition are analyzed for the case study of a coal-fired power plant in the southeastern United States. The effect of potential emission reductions at the plant on nitrogen deposition to Escambia Bay and its watershed on the Florida-Alabama border is simulated using the three-dimensional Eulerian Community Multiscale Air Quality (CMAQ) model. A method to quantify the relative and individual effects of NOx versus SO2 controls on nitrogen deposition using air quality modeling results obtained from the simultaneous application of NOx and SO2 emission controls is presented and discussed using the results from CMAQ simulations conducted with NOx-only and SO2-only emission reductions; the method applies only to cases in which ambient inorganic nitrate is present mostly in the gas phase; that is, in the form of gaseous nitric acid (HNO3). In such instances, the individual effects of NOx and SO2 controls on nitrogen deposition can be approximated by the effects of combined NOx + SO2 controls on the deposition of NOy, (the sum of oxidized nitrogen species) and reduced nitrogen species (NHx), respectively. The benefit of controls at the plant in terms of the decrease in nitrogen deposition to Escambia Bay and watershed is less than 6% of the overall benefit due to regional Clean Air Interstate Rule (CAIR) controls.

  2. 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.

  3. 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.

  4. Impact of aircraft NOx emissions on the atmosphere - tradeoffs to reduce the impact

    NASA Astrophysics Data System (ADS)

    Gauss, M.; Isaksen, I. S. A.; Lee, D. S.; Søvde, O. A.

    2006-05-01

    Within the EU-project TRADEOFF, the impact of NOx (=NO+NO2) emissions from subsonic aviation upon the chemical composition of the atmosphere has been calculated with focus on changes in reactive nitrogen and ozone. We apply a 3-D chemical transport model that includes comprehensive chemistry for both the troposphere and the stratosphere and uses various aircraft emission scenarios developed during TRADEOFF for the year 2000. The environmental effects of enhanced air traffic along polar routes and of possible changes in cruising altitude are investigated, taking into account effects of flight route changes on fuel consumption and emissions.

    In a reference case including both civil and military aircraft the model predicts aircraft-induced maximum increases of zonal-mean NOy (=total reactive nitrogen) between 156 pptv (August) and 322 pptv (May) in the tropopause region of the Northern Hemisphere. Resulting maximum increases in zonal-mean ozone vary between 3.1 ppbv in September and 7.7 ppbv in June.

    Enhanced use of polar routes implies substantially larger zonal-mean ozone increases in high Northern latitudes during summer, while the effect is negligible in winter.

    Lowering the flight altitude leads to smaller ozone increases in the lower stratosphere and upper troposphere, and to larger ozone increases at altitudes below. Regarding total ozone change, the degree of cancellation between these two effects depends on latitude and season, but annually and globally averaged the contribution from higher altitudes dominates, mainly due to washout of NOy in the troposphere, which weakens the tropospheric increase.

    Raising flight altitudes increases the ozone burden both in the troposphere and the lower stratosphere, primarily due to a more efficient accumulation of pollutants in the stratosphere.

  5. Effects of biodiesel made from swine- and chicken-fat residues on CO, CO2, and NOx emissions.

    PubMed

    Feddern, Vivian; Cunha Junior, Anildo; De Prá, Marina C; Busi da Silva, Marcio L; Nicoloso, Rodrigo da S; Higarashi, Martha M; Coldebella, Arlei; de Abreu, Paulo G

    2017-01-12

    Implications Emissions from motor vehicles can contribute considerably to the levels of greenhouse gases in the atmosphere. The use of biodiesel to replace or augment diesel can not only decrease our dependency on fossil fuels but also help decrease air pollution. Thus, different sources of feedstocks are constantly being explored for affordable biodiesel production. However, the amount of CO, CO2 and/or NOx emissions can vary largely depending on type of feedstock used to produce biodiesel. In this work we demonstrated animal fat feasibility in replacing petrodiesel with less impact regarding greenhouse gas emissions than other sources.

  6. 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.

  7. 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.

  8. 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

  9. 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.

  10. 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

  11. Emissions of HC, CO, NOx, CO2, and SO2 from civil aviation in China in 2010

    NASA Astrophysics Data System (ADS)

    Fan, Weiyi; Sun, Yifei; Zhu, Tianle; Wen, Yi

    2012-09-01

    Civil aviation in China has developed rapidly in recent years, and the effects of civil aviation emissions on the atmospheric environment should not be neglected. The establishment of emission inventories of atmospheric pollutants from civil aviation contributes to related policy formation and pollution control. According to the 2010's China flight schedules, aircraft/engine combination information and revised emission indices from the International Civil Aviation Organization emission data bank based on meteorological data, the fuel consumption and HC, CO, NOx, CO2, SO2 emissions from domestic flights of civil aviation in China (excluding Taiwan Province) in 2010 are estimated in this paper. The results show that fuel consumption in 2010 on domestic flights in China is 12.12 million tons (metric tons), HC, CO, NOx, CO2 and SO2 emissions are 4600 tons, 39,700 tons, 154,100 tons, 38.21 million tons and 9700 tons, respectively. The fuel consumption and pollutant emissions of China Southern Airline are responsible for the largest national proportion of each, accounting for 27% and 25-28%, respectively.

  12. Soot and NO(x) Emissions and Combustion Characteristics of Low Heat Rejection Direct Injection Diesel Engines

    DTIC Science & Technology

    1994-01-10

    Thin ceramic thermal barrier coatings were applied to the piston crown and bowl, the head and valves, and the cylinder liner. The coated piston and...performance. Coating the piston crown alone results in generally lower cylinder pressure, lower brake specific fuel consumption and lower NOx emission compared...thermal coatings. The computer modeling has led to an understanding of the effect of coating the piston on NO production. The hotter piston crown warms the

  13. 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.

  14. 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

  15. PM, NOx and butane emissions from on-road vehicle fleets in Hong Kong and their implications on emission control policy

    NASA Astrophysics Data System (ADS)

    Ning, Zhi; Wubulihairen, Maimaitireyimu; Yang, Fenhuan

    2012-12-01

    Vehicular emissions are the major sources of air pollution in urban areas. For metropolitan cities with large population working and living in environments with direct traffic impact, emission control is of great significance to protect public health. Implementation of more stringent emission standards, retrofitting fleet with emission control devices and switching to clearer fuel has been commonly practiced in different cities including Hong Kong. The present study employed a new plume chasing method for effective and quick evaluation of on-road fleet emission factors of particulate matter (PM), nitrogen oxides (NOx), and butane from heavy duty diesel trucks, diesel buses and liquefied petroleum gas (LPG) vehicles. The results showed distinct profiles of the emissions from different fleets with excessive butane emissions from LPG fleet and contrasting PM and NOx emissions from diesel trucks and buses fleets. A cross comparison was also made with emission data from other cities and from historic local studies. The implications of the observed difference on the effectiveness of emission control measures and policy are discussed with recommendations of direction for future research and policy making.

  16. 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.

  17. Influence of enhanced Asian NOx emissions on ozone in the upper troposphere and lower stratosphere in chemistry-climate model simulations

    NASA Astrophysics Data System (ADS)

    Roy, Chaitri; Fadnavis, Suvarna; Müller, Rolf; Ayantika, D. C.; Ploeger, Felix; Rap, Alexandru

    2017-01-01

    The Asian summer monsoon (ASM) anticyclone is the most pronounced circulation pattern in the upper troposphere and lower stratosphere (UTLS) during northern hemispheric summer. ASM convection plays an important role in efficient vertical transport from the surface to the upper-level anticyclone. In this paper we investigate the potential impact of enhanced anthropogenic nitrogen oxide (NOx) emissions on the distribution of ozone in the UTLS using the fully coupled aerosol-chemistry-climate model, ECHAM5-HAMMOZ. Ozone in the UTLS is influenced both by the convective uplift of ozone precursors and by the uplift of enhanced-NOx-induced tropospheric ozone anomalies. We performed anthropogenic NOx emission sensitivity experiments over India and China. In these simulations, covering the years 2000-2010, anthropogenic NOx emissions have been increased by 38 % over India and by 73 % over China with respect to the emission base year 2000. These emission increases are comparable to the observed linear trends of 3.8 % per year over India and 7.3 % per year over China during the period 2000 to 2010. Enhanced NOx emissions over India by 38 % and China by 73 % increase the ozone radiative forcing in the ASM anticyclone (15-40° N, 60-120° E) by 16.3 and 78.5 mW m-2 respectively. These elevated NOx emissions produce significant warming over the Tibetan Plateau and increase precipitation over India due to a strengthening of the monsoon Hadley circulation. However, increase in NOx emissions over India by 73 % (similar to the observed increase over China) results in large ozone production over the Indo-Gangetic Plain and Tibetan Plateau. The higher ozone concentrations, in turn, induce a reversed monsoon Hadley circulation and negative precipitation anomalies over India. The associated subsidence suppresses vertical transport of NOx and ozone into the ASM anticyclone.

  18. 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

  19. Estimation of NOx emissions from Delhi using Car MAX-DOAS observations and comparison with OMI satellite data

    NASA Astrophysics Data System (ADS)

    Shaiganfar, R.; Beirle, S.; Sharma, M.; Chauhan, A.; Singh, R. P.; Wagner, T.

    2011-11-01

    We present the first Multi-Axis-(MAX-) DOAS observations in India performed during April 2010 and January 2011 in Delhi and nearby regions. The MAX-DOAS instrument was mounted on a car roof, which allowed us to perform measurements along individual driving routes. From car MAX-DOAS observations along closed circles around Delhi, together with information on wind speed and direction, the NOx emissions from the greater Delhi area were determined: our estimate of 4.4 × 1025 molecules s-1 is found to be slightly lower than the corresponding emission estimates using the EDGAR emission inventory and substantially smaller compared to a recent study by Gurjar et al. (2004). We also determined NOx emissions from Delhi using OMI satellite observations on the same days. These emissions are slightly smaller than those from the car MAX-DOAS measurements. Finally the car MAX-DOAS observations were also used for the validation of simultaneous OMI satellite measurements of the tropospheric NO2 VCD and found a good agreement of the spatial patterns. Concerning the absolute values, OMI data are, on average, higher than the car MAX-DOAS observations close to strong emission sources, and vice versa over less polluted regions. Our results indicate that OMI NO2 VCDs are biased low over strongly polluted regions, probably caused by inadequate a-priori profiles used in the OMI satellite retrieval.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. Ammonia-Free NOx Control System

    SciTech Connect

    S. Wu

    2003-12-31

    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 31, 2003 time period.

  10. Catalytic reduction of NOx with NH3 over different-shaped MnO2 at low temperature.

    PubMed

    Tian, Wei; Yang, Hangsheng; Fan, Xiaoyu; Zhang, Xiaobin

    2011-04-15

    MnO(2) nanotubes, nanorods, and nanoparticles were prepared using a hydrothermal method, after which the different activities for selective catalytic reduction (SCR) of nitrogen oxides (NO(x)) were compared. MnO(2) nanorods performed the highest activity for reduction of NO(x) under a gas hourly space velocity of 36,000 h(-1) with conversion efficiencies of above 90% between 250 and 300 °C; it also had the highest removal efficiency of 98.2% at 300 °C. From the analysis of X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, temperature-programmed desorption, and temperature-programmed reduction, we can ascribe the high activity of MnO(2) nanorods to low crystallinity, more lattice oxygen, high reducibility, and a large number of strong acid sites. The apparent activation energy of the SCR reaction on the surface of nanorods was calculated to be 20.9 kJ/mol, which favored the reaction better than the other catalysts.

  11. Global partitioning of NOx sources using satellite observations: relative roles of fossil fuel combustion, biomass burning and soil emissions.

    PubMed

    Jaeglé, Lyatt; Steinberger, Linda; Martin, Randall V; Chance, Kelly

    2005-01-01

    We use space-based observations of NO2 columns from the Global Ozone Monitoring Experiment (GOME) to derive monthly top-down NOx emissions for 2000 via inverse modeling with the GEOS-CHEM chemical transport model. Top-down NOx sources are partitioned among fuel combustion (fossil fuel and biofuel), biomass burning and soils by exploiting the spatio-temporal distribution of remotely sensed fires and a priori information on the location of regions dominated by fuel combustion. The top-down inventory is combined with an a priori inventory to obtain an optimized a posteriori estimate of the relative roles of NOx sources. The resulting a posteriori fuel combustion inventory (25.6 TgN year(-1)) agrees closely with the a priori (25.4 TgN year(-1)), and errors are reduced by a factor of 2, from +/- 80% to +/- 40%. Regionally, the largest differences are found over Japan and South Africa, where a posteriori estimates are 25% larger than a priori. A posteriori fuel combustion emissions are aseasonal, with the exception of East Asia and Europe where winter emissions are 30-40% larger relative to summer emissions, consistent with increased energy use during winter for heating. Global a posteriori biomass burning emissions in 2000 resulted in 5.8 TgN (compared to 5.9 TgN year(-1) in the a priori), with Africa accounting for half of this total. A posteriori biomass burning emissions over Southeast Asia/India are decreased by 46% relative to a priori; but over North equatorial Africa they are increased by 50%. A posteriori estimates of soil emissions (8.9 TgN year(-1)) are 68% larger than a priori (5.3 TgN year(-1)). The a posteriori inventory displays the largest soil emissions over tropical savanna/woodland ecosystems (Africa), as well as over agricultural regions in the western U.S. (Great Plains), southern Europe (Spain, Greece, Turkey), and Asia (North China Plain and North India), consistent with field measurements. Emissions over these regions are highest during summer at

  12. 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.

  13. Estimating emissions reductions from vehicle retirement programs. Final report, January 1992-December 1996

    SciTech Connect

    Deysher, E.; Pickrell, D.

    1997-02-01

    This report assesses the effectiveness of vehicle retirement programs in reducing emissions from the motor vehicle fleets, as well as examining the effect of a program`s timing on the magnitude of these reductions. First, the eastern Massachusetts nonattainment area serves as an example to demonstrate the potential reductios in volatile organic compounds (VOC) and nitrous oxides (NOx) emissions for retirement of all light-duty vehicles over twenty years old. The assumption that all old vehicles are retired obviously represents and extreme approach to reducing emissions; however, it is meant to test the effectiveness as a policy measure, rather than designing a program specifically for Massachusetts. Second, components of the MOBILE model are examined to assess the model`s capablity to replicate real-world vehicular emissions.

  14. Constraints on Anthropogenic NOx Emissions from Geostationary Satellite Observations in a Regional Chemical Data Assimilation System: Evaluation Using Observing System Simulation Experiments

    NASA Astrophysics Data System (ADS)

    Liu, X.; Mizzi, A. P.; Anderson, J. L.; Fung, I. Y.; Cohen, R. C.

    2015-12-01

    Nitrogen oxides (NOx=NO+NO2) control the tropospheric ozone (O3) budget, the abundance of the hydroxyl radical (OH), the formation of organic and inorganic nitrate aerosol, and therefore affect air quality and climate. There remain significant uncertainties in the processes responsible for NOx emissions and subsequent mixing and chemical removal. NOx has a short lifetime and its emissions show high spatiotemporal variability at urban scale. Future geostationary satellite instruments including TEMPO, GEMS and Sentinel-4 will provide hourly time resolution and high spatial resolution observations providing maps of NO2 on diurnal and local scales. Here we determine the extent to which a TEMPO like instrument can quantify urban-scale NOx emissions using a regional data assimilation (DA) system comprising of a chemical transport model, WRF-Chem, a TEMPO simulator and the DART Ensemble Adjustment Kalman Filter. We generate synthetic TEMPO observations by sampling from a nature run on an urban scale domain. We consider the effect of albedo, surface pressure, solar and viewing angles and a priori NO2 profiles on the TEMPO NO2 averaging kernel to achieve scene-dependent instrument sensitivity. We estimate NOx emissions using DART in a state augmentation approach by including NOx emissions in the state vector being analyzed. The ensemble-based statistical estimation of error correlations between concentrations and emissions are critical as they determine the impact of assimilated observations. We describe observing system simulation experiments to explore the optimal approach in the ensemble-based DA system to estimate hourly-resolved NOx emissions from TEMPO NO2 observations. Several case studies will be presented examining the role of covariance localization length and chemical perturbations on the success of the approach.

  15. Global sources of non-CO2 greenhouse gas emissions: regional trends, uncertainties and options for emission reductions

    NASA Astrophysics Data System (ADS)

    Olivier, J. G.; van Aardenne, J. A.; Peters, J. A.

    2005-05-01

    An overview will be presented of sources and trends of global emissions of direct non-CO2 greenhouse gases CH4, N2O and the fluorinated gases HFCs, PFCs and SF6, which are addressed in the Kyoto protocol. Special attention will be given to regional source trends, estimated uncertainties and most recent global emission trends. In addition, the most significant options for emission reductions will be discussed in view of medium term emission scenarios that were meant to illustrate future trends without the effects climate policy. For estimating the recent global emission trends a special approach was used to compile fast annual updates of the EDGAR global emission inventories, based on the more detailed previous version. We present an overview of the approaches used for this `Fast Track' for the different source sectors. Results are presented for 1995-2002 for various anthropogenic sources at regional scales including an estimate of the accuracies achieved. A similar overview will be provided for the emissions of the ozone precursors NOx, CO and NMVOC and of black carbon. Tropospheric ozone and black carbon are both greenhouse gases, which are not considered in the Kyoto protocol, but in industrialised countries the emissions that cause them are often part of environmental policy on local and regional air quality.

  16. Advancements in low NOx tangential firing systems

    SciTech Connect

    Hein, R. von; Maney, C.; Borio, R.

    1996-12-31

    The most cost effective method of reducing nitrogen oxide emissions when burning fossil fuels, such as coal, is through in-furnace NOx reduction processes. ABB Combustion Engineering, Inc. (ABB CE), through its ABB Power Plant Laboratories has been involved in the development of such low NOx pulverized coal firing systems for many years. This development effort is most recently demonstrated through ABB CE`s involvement with the U.S. Department of Energy`s (DOE) {open_quotes}Engineering Development of Advanced Coal Fired Low-Emission Boiler Systems{close_quotes} (LEBS) project. The goal of the DOE LEBS project is to use {open_quotes}near term{close_quotes} technologies to produce a commercially viable, low emissions boiler. This paper addresses one of the key technologies within this project, the NOx control subsystem. The foundation for the work undertaken at ABB CE is the TFS 2000{trademark} firing system, which is currently offered on a commercial basis. This system encompasses sub-stoichiometric combustion in the main firing zone for reduced NOx formation. Potential enhancements to this firing system focus on optimizing the introduction of the air and fuel within the primary windbox to provide additional horizontal and vertical staging. As is the case with all in-furnace NOx control processes, it is necessary to operate the system in a manner which does not decrease NOx at the expense of reduced combustion efficiency.

  17. Impact of aircraft NOx emissions on tropospheric ozone calculated with a chemistry-general circulation model: Sensitivity to higher hydrocarbon chemistry

    NASA Astrophysics Data System (ADS)

    Kentarchos, A. S.; Roelofs, G. J.

    2002-07-01

    A three-dimensional chemistry-general circulation model has been employed to estimate the impact of current aircraft NOx emissions on tropospheric ozone. The model contains a representation of higher hydrocarbon chemistry, implemented by means of the Carbon Bond Mechanism 4 (CBM4), in order to investigate the potential effect of higher hydrocarbons on aircraft-induced ozone changes. Aircraft NOx emissions increase background NOX (= NO + NO2 + NO3 + 2N2O5 + HNO4) concentrations by 50-70 pptv in the upper troposphere over the Northern Hemisphere, and contribute up to 3 ppbv to upper tropospheric background ozone levels. When higher hydrocarbon chemistry is considered in the simulation, the aircraft-induced ozone perturbations are higher by ~12% during summer and the aircraft-induced ozone production efficiency per NOx molecule increases by ~20%, when compared to a simulation without higher hydrocarbon chemistry.

  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, 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...

  20. 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...

  1. 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...

  2. 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...

  3. NOx, FINE PARTICLE AND TOXIC METAL EMISSIONS FROM THE COMBUSTION OF SEWAGE SLUDGE/COAL MIXTURES: A SYSTEMATIC ASSESSMENT

    SciTech Connect

    Jost O.L. Wendt

    2003-01-31

    This research project focuses on pollutants from the combustion of mixtures of dried municipal sewage sludge (MSS) and coal. The objective is to determine the relationship between (1) fraction sludge in the sludge/coal mixture, and (2) combustion conditions on (a) NOx concentrations in the exhaust, (b) the size segregated fine and ultra-fine particle composition in the exhaust, and (c) the partitioning of toxic metals between vapor and condenses phases, within the process. The proposed study will be conducted in concert with an existing ongoing research on toxic metal partitioning mechanisms for very well characterized pulverized coals alone. Both high NOx and low NOx combustion conditions will be investigated (unstaged and staged combustion). Tradeoffs between CO{sub 2} control, NO{sub x} control, and inorganic fine particle and toxic metal emissions will be determined. Previous research results have demonstrated that the inhalation of coal/MSS ash particles cause an increase in lung permeability than coal ash particles alone. Elemental analysis of the coal/MSS ash particles showed that Zn was more abundant in these ash particles than the ash particles of coal ash alone.

  4. NOx, FINE PARTICLE AND TOXIC METAL EMISSIONS FROM THE COMBUSTION OF SEWAGE SLUDGE/COAL MIXTURES: A SYSTEMATIC ASSESSMENT

    SciTech Connect

    Jost O.L. Wendt

    2001-08-01

    This research project focuses on pollutants from the combustion of mixtures of dried municipal sewage sludge (MSS) and coal. The objective is to determine the relationship between (1) fraction sludge in the sludge/coal mixture, and (2) combustion conditions on (a) NOx concentrations in the exhaust, (b) the size segregated fine and ultra-fine particle composition in the exhaust, and (c) the partitioning of toxic metals between vapor and condenses phases, within the process. To this end work is progress using an existing 17kW downflow laboratory combustor, available with coal and sludge feed capabilities. The proposed study will be conducted in concert with an existing ongoing research on toxic metal partitioning mechanisms for very well characterized pulverized coals alone. Both high NOx and low NOx combustion conditions will be investigated (unstaged and staged combustion). The proposed work uses existing analytical and experimental facilities and draws on 20 years of research on NO{sub x} and fine particles that has been funded by DOE in this laboratory. Four barrels of dried sewage sludge are currently in the laboratory. Insofar as possible pertinent mechanisms will be elucidated. Tradeoffs between CO{sub 2} control, NO{sub x} control, and inorganic fine particle and toxic metal emissions will be determined. For the Third Quarter of this project we present our data on trace metal partitioning obtained from combustion of MSS and Gas, MSS and Coal and Coal and Gas alone.

  5. The Impact of Buoyancy and Flame Structure on Soot, Radiation and NOx Emissions from a Turbulent Diffusion Flame

    NASA Technical Reports Server (NTRS)

    Kennedy, I. M.; Kollman, W.; VanderWal, R. L.

    1999-01-01

    It is hypothesized that the spatial structure of a turbulent diffusion flame plays an important role in determining the emissions of radiative energy, soot and NO, from a combustor. This structure, manifested in the two point statistics, is influenced by buoyancy. Radiation, soot and NOx emissions are the cumulative result of processes that occur throughout a flame. For example, radiation fluxes along a line of sight can be found from summing up the contributions from sources in individual pockets of hot soot that emit, and from sinks in cold soot that absorb. Soot and NOx are both the results of slow chemistry and are not equilibrium products. The time that is available for production and burnout is crucial in determining the eventual emissions of these pollutants. Turbulence models generally rely on a single point closure of the appropriate time averaged equations. Hence, spatial information is lost and needs to be modeled using solution variables such as turbulence kinetic energy and dissipation rate, often with the assumption of isotropy. However, buoyancy can affect the physical structure of turbulent flames and can change the spatial extent of soot bearing regions. Theoretical comparisons with models are best done in the limit of infinite Froude number because the inclusion of buoyancy in flow models introduces significant uncertainties. Hence, LII measurements of soot, measurements of radiation fluxes from soot, Particle Imaging Velocimetry (PIV) of the flow field and measurements of post flame NOX will be carried out on the NASA Lewis 2.2 sec drop tower and eventually on the parabolic flight aircraft. The drop rig will be a modified version of a unit that has been successfully used at Lewis in the past.

  6. OPTIMIZED FUEL INJECTOR DESIGN FOR MAXIMUM IN-FURNACE NOx REDUCTION AND MINIMUM UNBURNED CARBON

    SciTech Connect

    SAROFIM, A F; LISAUSKAS, R; RILEY, D; EDDINGS, E G; BROUWER, J; KLEWICKI, J P; DAVIS, K A; BOCKELIE, M J; HEAP, M P; PERSHING, D

    1998-01-01

    Reaction Engineering International (REI) has established a project team of experts to develop a technology for combustion systems which will minimize NO x emissions and minimize carbon in the fly ash. This much need technology will allow users to meet environmental compliance and produce a saleable by-product. This study is concerned with the NO x control technology of choice for pulverized coal fired boilers,"in-furnace NOx control," which includes: staged low-NOx burners, reburning, selective non-catalytic reduction (SNCR) and hybrid approaches (e.g., reburning with SNCR). The program has two primary objectives: 1) To improve the performance of "in-furnace" NOx control, processes. 2) To devise new, or improve existing, approaches for maximum "in-furnace" NOx control and minimum unburned carbon. The program involves: 1) fundamental studies at laboratory- and bench-scale to define NO reduction mechanisms in flames and reburning jets; 2) laboratory experiments and computer modeling to improve our two-phase mixing predictive capability; 3) evaluation of commercial low-NOx burner fuel injectors to develop improved designs, and 4) demonstration of coal injectors for reburning and low-NOx burners at commercial scale. The specific objectives of the two-phase program are to: 1 Conduct research to better understand the interaction of heterogeneous chemistry and two phase mixing on NO reduction processes in pulverized coal combustion. 2 Improve our ability to predict combusting coal jets by verifying two phase mixing models under conditions that simulate the near field of low-NOx burners. 3 Determine the limits on NO control by in-furnace NOx control technologies as a function of furnace design and coal type. 5 Develop and demonstrate improved coal injector designs for commercial low-NOx burners and coal reburning systems. 6 Modify the char burnout model in REI's coal

  7. MOF-74 as an Efficient Catalyst for the Low-Temperature Selective Catalytic Reduction of NOx with NH3.

    PubMed

    Jiang, Haoxi; Wang, Qianyun; Wang, Huiqin; Chen, Yifei; Zhang, Minhua

    2016-10-12

    In this work, Mn-MOF-74 with hollow spherical structure and Co-MOF-74 with petal-like shape have been prepared successfully via the hydrothermal method. The catalysts were characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetry-mass spectrum analysis (TG-MS), N2 adsorption/desorption, scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). It is found that MOF-74(Mn, Co) exhibits the capability for selective catalytic reduction (SCR) of NOx at low temperatures. Both experimental (temperature-programmed desorption, TPD) and computational methods have shown that Co-MOF-74 and Mn-MOF-74 owned high adsorption and activation abilities for NO and NH3. The catalytic activities of Mn-MOF-74 and Co-MOF-74 for low-temperature denitrification (deNOx) in the presence of NH3 were 99% at 220 °C and 70% at 210 °C, respectively. It is found that the coordinatively unsaturated metal sites (CUSs) in M-MOF-74 (M = Mn and Co) played important roles in SCR reaction. M-MOF-74 (M = Mn and Co), especially Mn-MOF-74, showed excellent catalytic performance for low-temperature SCR. In addition, in the reaction process, NO conversion on Mn-MOF-74 decreased with the introduction of H2O and SO2 and almost recovered when gas was cut off. However, for Co-MOF-74, SO2 almost has no effect on the catalytic activity. This work showed that MOF-74 could be used prospectively as deNOx catalyst.

  8. NOx, FINE PARTICLE AND TOXIC METAL EMISSIONS FROM THE COMBUSTION OF SEWAGE SLUDGE/COAL MIXTURES: A SYSTEMATIC ASSESSMENT

    SciTech Connect

    Jost O.L. Wendt

    2002-08-15

    This research project focuses on pollutants from the combustion of mixtures of dried municipal sewage sludge (MSS) and coal. The objective is to determine the relationship between (1) fraction sludge in the sludge/coal mixture, and (2) combustion conditions on (a) NOx concentrations in the exhaust, (b) the size segregated fine and ultra-fine particle composition in the exhaust, and (c) the partitioning of toxic metals between vapor and condenses phases, within the process. The proposed study will be conducted in concert with an existing ongoing research on toxic metal partitioning mechanisms for very well characterized pulverized coals alone. Both high NOx and low NOx combustion conditions will be investigated (unstaged and staged combustion). Tradeoffs between CO2 control, NOx control, and inorganic fine particle and toxic metal emissions will be determined. Previous research has yielded data on trace metal partitioning for MSS by itself, with natural gas assist, for coal plus MSS combustion together, and for coal alone. We have re-evaluated the inhalation health effects of ash aerosol from combustion of MSS both by itself and also together with coal. We have concluded that ash from the co-combustion of MSS and coal is very much worse from an inhalation health point of view, than ash from either MSS by itself or coal by itself. The reason is that ZnO is not the ''bad actor'' as had been suspected before, but the culprit is, rather, sulfated Zn. The MSS supplies the Zn and the coal supplies the sulfur, and so it is the combination of coal and MSS that makes that process environmentally bad. If MSS is to be burned, it should be burned without coal, in the absence of sulfur.

  9. 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.

  10. Real-Time Control of Lean Blowout in a Turbine Engine for Minimizing No(x) Emissions

    NASA Technical Reports Server (NTRS)

    Zinn, Ben

    2004-01-01

    This report describes research on the development and demonstration of a controlled combustor operates with minimal NO, emissions, thus meeting one of NASA s UEET program goals. NO(x) emissions have been successfully minimized by operating a premixed, lean burning combustor (modeling a lean prevaporized, premixed LPP combustor) safely near its lean blowout (LBO) limit over a range of operating conditions. This was accomplished by integrating the combustor with an LBO precursor sensor and closed-loop, rule-based control system that allowed the combustor to operate far closer to the point of LBO than an uncontrolled combustor would be allowed to in a current engine. Since leaner operation generally leads to lower NO, emissions, engine NO, was reduced without loss of safety.

  11. Sulfation and Desulfation Behavior of Pt-BaO/MgO-Al2O3 NOx Storage Reduction Catalyst.

    PubMed

    Jeong, Soyeon; Kim, Do Heui

    2016-05-01

    The comparative study between Pt-BaO/Al2O3 and Pt-BaO/MgO-Al2O3 gives the information about the effect of MgO addition to Al2O3 support on the sulfation and desulfation behavior of Pt-BaO/MgO-Al2O3 NOx storage reduction catalyst. The sulfated two samples were analyzed by using element analysis (EA), X-ray diffraction (XRD), H2 temperature programmed reaction (H2 TPRX) and NOx uptake measurement. The amount of sulfur uptake on 2 wt% Pt-20 wt% BaO/Al2O3 and 2 wt% Pt-20 wt% BaO/MgO-Al2O3 are almost identical as 0.45 and 0.40 of S/Ba, respectively, which yields the drastic decrease in NOx uptake for both sulfated samples. However, after desulfa- tion with H2 at 600 degrees C, the residual sulfur amount on MgO-Al2O3 supported catalyst is three times larger than that on Al2O3 supported one, indicating that sulfur species formed on the former are more stable than those on the latter. It is also well corresponding to the H2 TPRX results where the main H2S peak from MgO-Al2O3 supported sample is observed at higher temperature than Al2O3 supported one, resulting in the lower NOx uptake activity of former sample than the latter one. Meanwhile, after desulfation of MgO-Al2O3 supported sample at 700 degrees C and 800 degrees C, the activity is recovered more significantly due to the removal of the large amount of sulfur while Al2O3 supported one decreases monotonically due to the sintering of Pt crystallite and the formation of BaAl2O4 phase. It is summarized that MgO-Al2O3 supported catalyst enhances the thermal stability of the catalyst, however, forms the stable sulfate species, which needs to be improved to develop the more sulfur resistant NSR catalyst system.

  12. Novel Ce-W-Sb mixed oxide catalyst for selective catalytic reduction of NOx with NH3

    NASA Astrophysics Data System (ADS)

    Liu, Jun; Li, Guo-qiang; Zhang, Yong-fa; Liu, Xiao-qing; Wang, Ying; Li, Yuan

    2017-04-01

    A novel Ce3W2SbOx catalyst prepared by the co-precipitation method have been investigated for the selective catalysis reduction (SCR) of NOx with NH3. It was found that the Ce-W-Sb oxide catalyst exhibited an excellent conversion ratio of NOx and a high tolerance to H2O and SO2 in a wide operation temperature window. The catalysts were characterized by N2-adsorption, XRD, Raman, H2-TPR, NH3-TPD, XPS and DRIFTS. The results suggest that the strong interaction between Sb, W and Ce species not only enhances the redox property of the catalyst but also increases the surface acidity, thus promoting the adsorption and activation of NH3 species, which is favorable for high NH3-SCR performance. Based on in situ DRIFTS results, it was concluded that the Langmuir-Hinshelwood (L-H) mechanism existed at the temperature of below 300 °C, while at above 300 °C the Eley-Rideal (E-R) mechanism dominate the NH3-SCR reaction over the Ce3W2SbOx catalyst. Overall, these findings indicate that Ce3W2SbOx is promising for industrial applications.

  13. 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...

  14. 180 MW demonstration of advanced tangentially-fired combustion techniques for the reduction of nitrogen oxide (NO{sub x}) emissions from coal-fired boilers. Technical progress report second quarter, 1991

    SciTech Connect

    Not Available

    1991-12-31

    ABB CE`s Low NOx Bulk Furnace Staging (LNBFS) System and Low NOx Concentric Firing System (LNCFS) are demonstrated in stepwise fashion. These systems incorporate the concept of advanced overfire air (AOFA), clustered coal nozzles, and offset air. A complete description of the installed technologies is provided in the following section. The primary objective of the Plant Lansing Smith demonstration is to determine the long-term effects of commercially available tangentially-fired low NOx combustion technologies on NOx emissions and boiler performance. Short-term tests of each technology are also being performed to provide engineering information about emissions and performance trends. A target of achieving fifty percent NOx reduction using combustion modifications has been established for the project.

  15. [Selective catalytic reduction of NOx over Pd/CeZr/TiO2/Al2O3 wire-mesh honeycomb catalysts].

    PubMed

    Sun, Hong; Quan, Xie; Zhang, Yao-bin; Zhao, Ya-zhi

    2008-06-01

    Pd/CeZr/TiO2/Al2O3 wire-mesh honeycomb catalyst was prepared by sol-gel and impregnation. Furthermore, selective catalytic reduction of NOx over Pd/CeZr/TiO2/Al2O3 wire-mesh honeycomb catalyst with propylene under lean burn condition was studied. The effects of the concentration of tetra-n-butyl titanate and dipcoat cycles on TiO2 washcoat were studied by SEM, and the effects of Pd concentration, O2 concentration and gas velocity on catalytic activity were investigated. The experimental results showed that the TiO2 washcoat on wire-mesh support is even and crack-free when the support is impregnated in 20.0% tetra- n-butyl titanate sol for 2 cycles. The NOx conversion decreases with Pd concentration increase. When Pd concentration is 0.23%, NOx conversion is highest. NOx conversion increases with oxygen concentration increase in the range of 1.5%-6.0%. However, when oxygen concentration is higher than 6.0%, NOx conversion decreases with increasing oxygen concentration. The NOx conversion decreases with gas velocity increase and its effect is severer at high temperature than low temperature.

  16. Experiment and mechanism investigation on advanced reburning for NO(x) reduction: influence of CO and temperature.

    PubMed

    Wang, Zhi-Hua; Zhou, Jun-Hu; Zhang, Yan-Wei; Lu, Zhi-Min; Fan, Jian-Ren; Cen, Ke-Fa

    2005-03-01

    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% approximately 25% reburn heat input, temperature range from 1100 degrees C to 1400 degrees 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 degrees 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 degrees C approximately 1100 degrees 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 NO(x) 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.

  17. Nitrogen fluxes in response to changing NOx emissions and deposition at EPA's Mid-Atlantic Long Term Monitoring (LTM) stream sites, 1990-2009

    NASA Astrophysics Data System (ADS)

    Funk, C.; Lynch, J. A.

    2012-12-01

    Surface water chemistry provides direct indicators of the potential effects of anthropogenic impacts, such as acid deposition and climate change, on the overall health of aquatic ecosystems. Long-term surface water monitoring networks provide a host of environmental data that can be used, in conjunction with other networks, to assess how water bodies respond to stressors and if they are potentially at risk (e.g., receiving pollutant deposition beyond its critical load). Two EPA-administered monitoring programs provide information on the effects of acidic deposition on headwater aquatic systems: the Temporally Integrated Monitoring of Ecosystems (TIME) program and Long Term Monitoring (LTM) program, designed to track the effectiveness of the 1990 Clean Air Act Amendments (CAAA) in reducing the acidity of surface waters in the Northeast and Mid-Atlantic. Here we compare trends in inorganic nitrogen emissions and deposition to streamwater nitrate (NO3-) concentration trends and NO3- export in headwater Mid-Atlantic streams. Annual NOx emissions from the fossil fuel based power sector, regulated under Title IV of the 1990 CAAA, decreased 67% from 6.7 million tones in 1990 to 2.0 million tones in 2009. Commensurate with decreased NOx emissions, there was a 31% reduction in total inorganic nitrogen deposition in the Mid-Atlantic region, from 8.7 kg N/ha to 6.0 kg N/yr. Over the same time period, surface water nitrate concentrations in headwater streams in the Northern Appalachian Plateau (n=9) and Central Appalachian mountains (n=66) improve (show a decreasing NO3- trend) at 30% and 50% of monitored sites, respectively. Despite these improvements, only 10% of monitored Appalachian streams show improvement in critical load status to no longer exceed the acid sensitivity threshold and experience adverse ecological effects. Information from long-term monitoring has shown that emission reductions have in improved environmental conditions and increased ecosystem protection

  18. Method to monitor HC-SCR catalyst NOx reduction performance for lean exhaust applications

    DOEpatents

    Viola, Michael B [Macomb Township, MI; Schmieg, Steven J [Troy, MI; Sloane, Thompson M [Oxford, MI; Hilden, David L [Shelby Township, MI; Mulawa, Patricia A [Clinton Township, MI; Lee, Jong H [Rochester Hills, MI; Cheng, Shi-Wai S [Troy, MI

    2012-05-29

    A method for initiating a regeneration mode in selective catalytic reduction device utilizing hydrocarbons as a reductant includes monitoring a temperature within the aftertreatment system, monitoring a fuel dosing rate to the selective catalytic reduction device, monitoring an initial conversion efficiency, selecting a determined equation to estimate changes in a conversion efficiency of the selective catalytic reduction device based upon the monitored temperature and the monitored fuel dosing rate, estimating changes in the conversion efficiency based upon the determined equation and the initial conversion efficiency, and initiating a regeneration mode for the selective catalytic reduction device based upon the estimated changes in conversion efficiency.

  19. 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; Veres, Patrick; Williams, Jonathan; Wagner, Thomas

    2016-04-01

    Soil emissions of NOx (≡ NO + NO2), stemming from biotic emissions of NO, represent a considerable fraction of total NOx emissions, and may even dominate in agricultural and remote areas. Rain-induced spikes in NOx have been observed by in-situ measurements and also satellite observations. However, the estimation of soil emissions over broad geographic regions and on short time scales remains uncertain. This study presents a top-down approach to estimate pulsed soil emissions of trace gases on a global scale using tropospheric NO2 column densities (as a proxy for NOx) as observed by OMI, GOME-2 and SCIAMACHY. We introduce an optimized algorithm that synchronizes and averages multiple time series of atmospheric variables either from one location only, or also from different grid pixels, by aligning them on a relative scale to each other. This method allows investigating changes in the evolution of NO2 VCDs around the first day of rainfall after a prolonged dry period with a temporal resolution of one day and a spatial resolution of 0.25° . We find enhancements in NO2 VCDs on the day of first rainfall in many semi-arid regions in the world which are highly dependent on the season and land cover type. Strongest and most clustered enhancements are found in the distinct band of the Sahel region during the onset of the wet season in April-May-June. Absolute enhancements averaged over the Sahel region for four seasons from 2007 to 2010 range from 0.3*1015molec cm-2 for OMI to 0.4*1015molec cm-2 for GOME-2 and SCIAMACHY on the first day of rainfall. A thorough analysis of other influences on the retrieved signal as well as sensitivity studies are conducted which help to better characterize these short term enhancements. Translating the observed enhancements in NO2 VCDs to emission rates, leads to estimates between 5 and 65 ng N m-2 s-1 for the first day of rainfall which is in line with previous literature. We find that the enhancement in NO2 VCDs already starts to

  20. NOx reduction in natural gas high-performance burners laboratory burner evaluation and design optimization. Topical report, December 1989-May 1992

    SciTech Connect

    Syska, A.J.; Benson, C.E.; Beer, J.M.; Toqan, M.; Moreland, D.

    1994-09-01

    The report summarizes the results of the first two phases of a program aimed at developing a low NO(x) burner suitable for high temperature industrial applications, where NO(x) emissions can become extremely high. The program was one of two addressing this important objective. The second, a collaboration between Eclipse Combustion and Altex Technologies also has achieved technical success. Each program aimed at slightly different combustion applications, with this burner being well suited for smaller furnace applications while the Eclipse/Altex burner is better suited for large-scale furnaces such as steel reheating.

  1. Nox control for high nitric oxide concentration flows through combustion-driven reduction

    DOEpatents

    Yeh, James T.; Ekmann, James M.; Pennline, Henry W.; Drummond, Charles J.

    1989-01-01

    An improved method for removing nitrogen oxides from concentrated waste gas streams, in which nitrogen oxides are ignited with a carbonaceous material in the presence of substoichiometric quantities of a primary oxidant, such as air. Additionally, reductants may be ignited along with the nitrogen oxides, carbonaceous material and primary oxidant to achieve greater reduction of nitrogen oxides. A scrubber and regeneration system may also be included to generate a concentrated stream of nitrogen oxides from flue gases for reduction using this method.

  2. 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.

  3. OXYGEN ENHANCED COMBUSTION FOR NOx CONTROL

    SciTech Connect

    David R. Thompson; Lawrence E. Bool; Jack C. Chen

    2004-04-01

    Conventional wisdom says adding oxygen to a combustion system enhances product throughput, system efficiency, and, unless special care is taken, increases NOx emissions. This increase in NOx emissions is typically due to elevated flame temperatures associated with oxygen use leading to added thermal NOx formation. Innovative low flame temperature oxy-fuel burner designs have been developed and commercialized to minimize both thermal and fuel NOx formation for gas and oil fired industrial furnaces. To be effective these systems require close to 100% oxy-fuel combustion and the cost of oxygen is paid for by fuel savings and other benefits. For applications to coal-fired utility boilers at the current cost of oxygen, however, it is not economically feasible to use 100% oxygen for NOx control. In spite of this conventional wisdom, Praxair and its team members, in partnership with the US Department of Energy National Energy Technology Laboratory, have developed a novel way to use oxygen to reduce NOx emissions without resorting to complete oxy-fuel conversion. In this concept oxygen is added to the combustion process to enhance operation of a low NOx combustion system. Only a small fraction of combustion air is replaced with oxygen in the process. By selectively adding oxygen to a low NOx combustion system it is possible to reduce NOx emissions from nitrogen-containing fuels, including pulverized coal, while improving combustion characteristics such as unburned carbon. A combination of experimental work and modeling was used to define how well oxygen enhanced combustion could reduce NOx emissions. The results of this work suggest that small amounts of oxygen replacement can reduce the NOx emissions as compared to the air-alone system. NOx emissions significantly below 0.15 lbs/MMBtu were measured. Oxygen addition was also shown to reduce carbon in ash. Comparison of the costs of using oxygen for NOx control against competing technologies, such as SCR, show that this

  4. NOx, FINE PARTICLE AND TOXIC METAL EMISSIONS FROM THE COMBUSTION OF SEWAGE SLUDGE/COAL MIXTURES: A SYSTEMATIC ASSESSMENT

    SciTech Connect

    Jost O.L. Wendt

    2001-01-31

    This research project focuses on pollutants from the combustion of mixtures of dried municipal sewage sludge (MSS) and coal. The objective is to determine the relationship between (1) fraction sludge in the sludge/coal mixture, and (2) combustion conditions on (a) NOx concentrations in the exhaust, (b) the size segregated fine and ultra-fine particle composition in the exhaust, and (c) the partitioning of toxic metals between vapor and condenses phases, within the process. To this end we shall use an existing 17kW downflow laboratory combustor