Control of Nitrogen Dioxide in Stack Emission by Reaction with Ammonia

NASA Technical Reports Server (NTRS)

Metzler, A. J.; Stevenson, E. F.

1970-01-01

The development of an acid base gas-phase reaction system which utilizes anhydrous ammonia as the reactant to remove nitrogen dioxide from hydrazine-nitrogen tetroxide rocket combustion exhaust is reported. This reaction reduced NO2 levels in exhaust emissions so that the resulting stack emission is completely white instead of the earlier observed typical reddish-brown coloration. Preliminary analyses indicate the importance of reaction time and ammonia concentration on removal efficiency and elimination of the health hazard to individuals with respiratory problems.

PCDD/F emissions during startup and shutdown of a hazardous waste incinerator.

PubMed

Li, Min; Wang, Chao; Cen, Kefa; Ni, Mingjiang; Li, Xiaodong

2017-08-01

Compared with municipal solid waste incineration, studies on the PCDD/F emissions of hazardous waste incineration (HWI) under transient conditions are rather few. This study investigates the PCDD/F emission level, congener profile and removal efficiency recorded during startup and shutdown by collecting flue gas samples at the bag filter inlet and outlet and at the stack. The PCDD/F concentration measured in the stack gas during startup and shutdown were 0.56-4.16 ng I-TEQ Nm -3 and 1.09-3.36 ng I-TEQ Nm -3 , respectively, far exceeding the present codes in China. The total amount of PCDD/F emissions, resulting from three shutdown-startup cycles of this HWI-unit is almost equal to that generated during one year under normal operating conditions. Upstream the filter, the PCDD/F in the flue gas is mainly in the particle phase; however, after being filtered PCDD/F prevails in the gas phase. The PCDD/F fraction in the gas phase even exceeds 98% after passing through the alkaline scrubber. Especially higher chlorinated PCDD/F accumulate on inner walls of filters and ducts during these startup periods and could be released again during normal operation, significantly increasing PCDD/F emissions. Copyright © 2017. Published by Elsevier Ltd.

40 CFR 98.173 - Calculating GHG emissions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... associated requirements for Tier 4 in subpart C of this part (General Stationary Fuel Combustion Sources). (b..., dry basis (% CO2). Q = Hourly stack gas volumetric flow rate (scfh). %H2O = Hourly moisture percentage... reduction furnace are vented through the same stack as any combustion unit or process equipment that reports...

Herschel Far Infrared Spectra of Dusty Star-Forming Galaxies

NASA Astrophysics Data System (ADS)

Wilson, Derek; Cooray, Asantha R.; Nayyeri, Hooshang

2017-01-01

We stack archival spectra from the Herschel Space Observatory's SPIRE Spectrometer in three redshift bins from low redshifts (z < 0.2), through intermediate redshifts (0.2 < z < 1), and up to high redshifts (z > 1) in order to determine the average properties of the gas and dust in dusty, star-forming galaxies and (U)LIRGs. In the lower-redshift stack, we detect a host of water and carbon monoxide rotational transition lines, as well as some fine structure lines such as [NII]. At intermediate redshifts, only a [CII] line appears. The high-redshift stack displays strong [CII] emission, as well as faint emission from [OI] and [OIII]. The observed emission lines are used to model the average number density and radiation field strength in the photodissociation regions of our high-redshift sample, and the spectral line energy distributions of CO rotational transitions from the low-redshift stack are presented.

Theoretical analysis of stack gas emission velocity measurement by optical scintillation

NASA Astrophysics Data System (ADS)

Yang, Yang; Dong, Feng-Zhong; Ni, Zhi-Bo; Pang, Tao; Zeng, Zong-Yong; Wu, Bian; Zhang, Zhi-Rong

2014-04-01

Theoretical analysis for an online measurement of the stack gas flow velocity based on the optical scintillation method with a structure of two parallel optical paths is performed. The causes of optical scintillation in a stack are first introduced. Then, the principle of flow velocity measurement and its mathematical expression based on cross correlation of the optical scintillation are presented. The field test results show that the flow velocity measured by the proposed technique in this article is consistent with the value tested by the Pitot tube. It verifies the effectiveness of this method. Finally, by use of the structure function of logarithmic light intensity fluctuations, the theoretical explanation of optical scintillation spectral characteristic in low frequency is given. The analysis of the optical scintillation spectrum provides the basis for the measurement of the stack gas flow velocity and particle concentration simultaneously.

40 CFR 75.22 - Reference test methods.

Code of Federal Regulations, 2011 CFR

2011-07-01

... recertification of continuous emission monitoring Systems; NOX emission tests of low mass emission units under... continuous moisture monitoring systems are conducted. For the purpose of determining the stack gas molecular... traverse requirement of the method; (iv) Section 8.6 of the method allowing for the use of “Dynamic Spiking...

Comparion of Mercury Emissions Between Circulating Fluidized Bed Boiler and Pulverized Coal Boiler

NASA Astrophysics Data System (ADS)

Wang, Y. J.; Duan, Y. F.; Zhao, C. S.

Mercury emissions between a circulating fluidized bed (CFB) utility boiler and two pulverized coal (PC) boilers equipped with electrostatic precipitators (ESP) were in situ measured and compared. The standard Ontario Hydro Method (OHM) was used to sample the flue gas before and after the ESP. Various mercury speciations such as Hg0, Hg2+ and Hgp in flue gas and total mercury in fly ashes were analyzed. The results showed that the mercury removal rate of the CFB boiler is nearly 100%; the mercury emission in stack is only 0.028 g/h. However, the mercury removal rates of the two PC boilers are 27.56% and 33.59% respectively, the mercury emissions in stack are 0.80 and 51.78 g/h respectively. It concluded that components of the ESP fly ashes especially their unburnt carbons have remarkable influence on mercury capture. Pore configurations of fine fly ash particles have non-ignored impacts on mercury emissions.

Hidden Active Galactic Nuclei in Early-type Galaxies

NASA Astrophysics Data System (ADS)

Paggi, Alessandro; Fabbiano, Giuseppina; Civano, Francesca; Pellegrini, Silvia; Elvis, Martin; Kim, Dong-Woo

2016-06-01

We present a stacking analysis of the complete sample of early-type galaxies (ETGs) in the Chandra COSMOS (C-COSMOS) survey, to explore the nature of the X-ray luminosity in the redshift and stellar luminosity ranges 0\\lt z\\lt 1.5 and {10}9\\lt {L}K/{L}⊙ \\lt {10}13. Using established scaling relations, we subtract the contribution of X-ray binary populations to estimate the combined emission of hot ISM and active galactic nuclei (AGNs). To discriminate between the relative importance of these two components, we (1) compare our results with the relation observed in the local universe {L}X,{gas}\\propto {L}K4.5 for hot gaseous halos emission in ETGs, and (2) evaluate the spectral signature of each stacked bin. We find two regimes where the non-stellar X-ray emission is hard, consistent with AGN emission. First, there is evidence of hard, absorbed X-ray emission in stacked bins including relatively high z (˜1.2) ETGs with average high X-ray luminosity ({L}X {- {LMXB}}≳ 6× {10}42 {{erg}} {{{s}}}-1). These luminosities are consistent with the presence of highly absorbed “hidden” AGNs in these ETGs, which are not visible in their optical-IR spectra and spectral energy distributions. Second, confirming the early indication from our C-COSMOS study of X-ray detected ETGs, we find significantly enhanced X-ray luminosity in lower stellar mass ETGs ({L}K≲ {10}11{L}⊙ ), relative to the local {L}X,{gas}\\propto {L}K4.5 relation. The stacked spectra of these ETGs also suggest X-ray emission harder than expected from gaseous hot halos. This emission is consistent with inefficient accretion {10}-5-{10}-4{\\dot{M}}{Edd} onto {M}{BH}˜ {10}6-{10}8 {M}⊙ .

DOE Office of Scientific and Technical Information (OSTI.GOV)

M. L. Abbott; K. N. Keck; R. E. Schindler

This screening level risk assessment evaluates potential adverse human health and ecological impacts resulting from continued operations of the calciner at the New Waste Calcining Facility (NWCF) at the Idaho Nuclear Technology and Engineering Center (INTEC), Idaho National Engineering and Environmental Laboratory (INEEL). The assessment was conducted in accordance with the Environmental Protection Agency (EPA) report, Guidance for Performing Screening Level Risk Analyses at Combustion Facilities Burning Hazardous Waste. This screening guidance is intended to give a conservative estimate of the potential risks to determine whether a more refined assessment is warranted. The NWCF uses a fluidized-bed combustor to solidifymore » (calcine) liquid radioactive mixed waste from the INTEC Tank Farm facility. Calciner off volatilized metal species, trace organic compounds, and low-levels of radionuclides. Conservative stack emission rates were calculated based on maximum waste solution feed samples, conservative assumptions for off gas partitioning of metals and organics, stack gas sampling for mercury, and conservative measurements of contaminant removal (decontamination factors) in the off gas treatment system. Stack emissions were modeled using the ISC3 air dispersion model to predict maximum particulate and vapor air concentrations and ground deposition rates. Results demonstrate that NWCF emissions calculated from best-available process knowledge would result in maximum onsite and offsite health and ecological impacts that are less then EPA-established criteria for operation of a combustion facility.« less

Production of Jet Fuels from Coal Derived Liquids. Volume 10. Jet Fuels Production By-Products, Utility and Sulfur Emissions Control Integration Study

DTIC Science & Technology

1989-06-01

FLUE GAS DESULFURIZATION EVALUATION A-1/A-2 3-1. 3 BOILER STACK EMISSION CONTROL WITH...Appendices A - BACT Flue Gas Desulfurization Evaluation B - BACT Off- Gas Refrigeration Evaluation v LIST OF FIGURES Figure Page 1. Material Balance for...2. Desulfurize the flue gases from the Riley boilers when firing with high sulfur oils or lignite. Options in this category include commercial wet

40 CFR 98.173 - Calculating GHG emissions.

Code of Federal Regulations, 2012 CFR

2012-07-01

... associated requirements for Tier 4 in subpart C of this part (General Stationary Fuel Combustion Sources). (b... basis (% CO2). Q = Hourly stack gas volumetric flow rate (scfh). %H2O = Hourly moisture percentage in... furnace are vented through the same stack as any combustion unit or process equipment that reports CO2...

40 CFR Table I-12 to Subpart I of... - Default Emission Factors (1-Uij) for Gas Utilization Rates (Uij) and By-Product Formation Rates...

Code of Federal Regulations, 2014 CFR

2014-07-01

... Use With the Stack Test Method (300 mm and 450 mm Wafers) I Table I-12 to Subpart I of Part 98... (Bijk) for Semiconductor Manufacturing for Use With the Stack Test Method (300 mm and 450 mm Wafers...

40 CFR Table I-11 to Subpart I of... - Default Emission Factors (1-Uij) for Gas Utilization Rates (Uij) and By-Product Formation Rates...

Code of Federal Regulations, 2014 CFR

2014-07-01

... Use With the Stack Test Method (150 mm and 200 mm Wafers) I Table I-11 to Subpart I of Part 98... (Bijk) for Semiconductor Manufacturing for Use With the Stack Test Method (150 mm and 200 mm Wafers...

Energy Conservation Alternatives Study (ECAS): Conceptual Design and Implementation Assessment of a Utility Steam Plant with Conventional Furnace and Wet Lime Stack Gas Scrubbers

NASA Technical Reports Server (NTRS)

Brown, Dale H.

1976-01-01

A study was performed to estimate the technical/economic characteristics of a steam power plant (3500 pounds per square inch gauge, 1000 degrees Fahrenheit / 1000 degrees Fahrenheit) with a coal-burning radiant furnace and a wet lime stack gas scrubber to control sulfur emissions. Particulate emissions were controlled by an electrostatic precipitator operating at 300 degrees Fahrenheit. The stack gas from the scrubber was reheated from 125 degrees Fahrenheit to 250 degrees Fahrenheit as a base case, and from 125 degrees Fahrenheit to 175 degrees Fahrenheit as an alternate case. The study was performed on a basis consistent with the General Electric ECAS Phase II evaluation of advanced energy conversion systems for electric utility baseload applications using coal or coal-derived fuels. A conceptual design of the power plant was developed, including the on-site calcination of limestone to lime and the provision of sludge ponds to store the products of flue gas scrubbing. From this design, estimates were derived for power plant efficiency, capital cost, environmental intrusion characteristics, natural resource requirements, and cost of electricity at an assumed capacity factor of 65 percent. An implementation assessment was performed where factors affecting applicability of the conceptual design power plant in electric utility generation systems were appraised. At 250 degrees Fahrenheit and 175 degrees Fahrenheit stack gas temperatures respectively, the plants showed a cost of electricity of 39.8 and 37.0 mills per kilowatt-hours and overall plant efficiencies of 32 percent and 34 percent.

A SCREENING LEVEL RISK ASSESSMENT OF THE INDIRECT IMPACTS FROM THE COLUMBUS WASTE TO ENERGY FACILITY IN COLUMBUS, OHIO

EPA Science Inventory

Testing for emissions of dioxins from the stack of the Columbus, Ohio Waste to Energy (WTE) municipal solid waste combustion facility in 1992 implied that dioxin concentrations in stack gas averaged 328 ng TEQ/m3. The incinerator had been in operation since the early 1980s. In ...

Correlation of plume opacity with particles and sulfates from boilers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lou, J.C.; Lee, M.; Chen, K.S.

1997-07-01

The effects of emission concentrations of particulate matters and sulfates on plume opacity are investigated by in situ measurements. The studies are conducted for three processes of two coal-fired plants and one oil-fired that are all equipped with electrostatic precipitators. Flue-gas sampling and analysis include the concentrations of particles and total water soluble sulfates, particle size distribution, and flue-gas composition; while in-stack and out-of-stack opacities are determined by a transmissometer and certified smoke inspectors, respectively. Experimental results show that plume opacity outside the stack linearly correlates well with the in-stack opacity. The mixing of hot flue gas with cold ambientmore » air would result in the condensation of hygroscopic sulfuric acid aerosols and an increase about 1.6% out of typical 15--25% measured opacity. An empirical equation similar to the Beer-Lambert-Bouger form is derived for predicting the plume opacity in terms of the stack diameter and the concentrations of particles and total water soluble sulfates. Good comparisons are achieved between predictions by the empirical equation and other available field data.« less

Natural gas availability and ambient air quality in the Baton Rouge/New Orleans industrial complex

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fieler, E.R.; Harrison, D.P.

1978-02-26

Three scenarios were modeled for the Baton Rouge/New Orleans area for 1985: one assumes the substitution of residual oil (0.7% sulfur) for gas to decrease gas-burning stationary sources from 80 to 8% and the use of properly designed stacks for large emitters; the second makes identical gas supply assumptions but adds proper stack dispersion for medium as well as large emitters; and the third is based on 16% gas-burning stationary sources. The Climatological Dispersion Model was used to translate (1974) emission rates into ambient air concentrations. Growth rates for residential, commercial, and transportation sources, but not industry, were considered. Themore » results show that proper policies, which would require not only tall stacks for large oil burning units (and for intermediate units also in the areas of high industrial concentration), but also the careful location of new plants would permit continued industrial expansion without severe air pollution problems.« less

Emission characteristic of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) from medical waste incinerators (MWIs) in China in 2016: A comparison between higher emission levels of MWIs and lower emission levels of MWIs.

PubMed

Li, Jiafu; Lv, Zhiwei; Du, Lei; Li, Xiaonan; Hu, Xuepeng; Wang, Chong; Niu, Zhiguang; Zhang, Ying

2017-02-01

Emission characteristic of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) from 12 medical waste incinerators (MWIs) which have a total yearly capacity of 523 440 ton medical waste and accounted for 8.1% of total yearly capacity of 246 MWIs in China were studied. The congeners profile, emissions and toxic equivalent concentrations (TEQ) indicators of PCDD/Fs in stack gas from two groups of MWIs were researched, and the possible formation mechanisms of PCDD/Fs from MWIs were preliminarily discussed. The results of present study were summarized as follows. (1) The total concentrations and TEQ of PCDD/Fs in stack gas from MWIs were 0.516-122.803 ng Nm -3 and 0.031-3.463 ng I-TEQ Nm -3 , respectively. (2) 1,2,3,4,6,7,8-H7CDF, O8CDD, O8CDF and 1,2,3,4,6,7,8-H7CDD were the indicatory PCDD/Fs of MWI source, which could be used to apportion the sources of PCDD/Fs in environmental medium in China. (3) The emission factors of PCDD/Fs from MWIs ranged from 32.7 to 4900.0 ng I-TEQ ton -1 with a mean of 1923.6 ng I-TEQ ton -1 . (4) The gas emissions of PCDD/Fs from researched 12 MWIs and all of MWIs in China in 2016 were 37.742 and 465.951 mg I-TEQ year -1 , respectively. (5) 1,2,3,7,8,9-H6CDF and 1,2,3,4,7,8-H6CDF were effective TEQ indicators for the real-time monitoring of the PCDD/Fs emission. (6) The congeners profile and factor composition of PCDD/Fs in stack gas from two groups of MWIs were researched based on positive matrix factorization (PMF) model, and the possible formation mechanisms of PCDD/Fs from MWIs were preliminarily discussed. Copyright © 2016 Elsevier Ltd. All rights reserved.

Research and development of a field-ready protocol for sampling of phosgene from stationary source emissions: Diethylamine reagent studies. Research report, 11 July 1995--30 September 1996

DOE Office of Scientific and Technical Information (OSTI.GOV)

Steger, J.L.; Bursey, J.T.; Merrill, R.G.

1999-03-01

This report presents the results of laboratory studies to develop and evaluate a method for the sampling and analysis of phosgene from stationary sources of air emissions using diethylamine (DEA) in toluene as the collection media. The method extracts stack gas from emission sources and stabilizes the reactive gas for subsequent analysis. DEA was evaluated both in a benchtop study and in a laboratory train spiking study. This report includes results for both the benchtop study and the train spiking study. Benchtop studies to evaluate the suitability of DEA for collecting and analyzing phosgene investigated five variables: storage time, DEAmore » concentration, moisture/pH, phosgene concentration, and sample storage temperature. Prototype sampling train studies were performed to determine if the benchtop chemical studies were transferable to a Modified Method 5 sampling train collecting phosgene in the presence of clean air mixed with typical stack gas components. Four conditions, which varied the moisture and phosgene spike were evaluated in triplicate. In addition to research results, the report includes a detailed draft method for sampling and analysis of phosgene from stationary source emissions.« less

Modification of the ECAS reference steam power generating plant to comply with the EPA 1979 new source performance standards

NASA Technical Reports Server (NTRS)

Fogelson, S. A.; Chait, I. L.; Bradley, W. J.; Benson, W.

1980-01-01

Detailed capital cost estimates for the ECAS and modified reference plants in mid-1978 dollars for both 250 and 175 F (394 and 353 K) stack gas reheat temperatures based on the cost estimates developed for the ECAS study are presented. The scope of the work included technical assessment of sulfur dioxide scrubber system design, on site calcination versus purchased lime, reheat of stack gas, effect of sulfur dioxide scrubber on particulate emission, and control of nitrogen oxides.

40 CFR 98.172 - GHGs to report.

Code of Federal Regulations, 2014 CFR

2014-07-01

... combustion units include, but are not limited to, by-product recovery coke oven battery combustion stacks... flares that burn blast furnace gas or coke oven gas according to the procedures in § 98.253(b)(1) of...)(B) and § 98.253(b)(1)(iii)(C), you must use the default CO2 emission factors for coke oven gas and...

40 CFR 98.172 - GHGs to report.

Code of Federal Regulations, 2012 CFR

2012-07-01

... combustion units include, but are not limited to, by-product recovery coke oven battery combustion stacks... flares that burn blast furnace gas or coke oven gas according to the procedures in § 98.253(b)(1) of...)(B) and § 98.253(b)(1)(iii)(C), you must use the default CO2 emission factors for coke oven gas and...

40 CFR 98.172 - GHGs to report.

Code of Federal Regulations, 2013 CFR

2013-07-01

... combustion units include, but are not limited to, by-product recovery coke oven battery combustion stacks... flares that burn blast furnace gas or coke oven gas according to the procedures in § 98.253(b)(1) of...)(B) and § 98.253(b)(1)(iii)(C), you must use the default CO2 emission factors for coke oven gas and...

40 CFR 98.172 - GHGs to report.

Code of Federal Regulations, 2011 CFR

2011-07-01

... combustion units include, but are not limited to, by-product recovery coke oven battery combustion stacks... flares that burn blast furnace gas or coke oven gas according to the procedures in § 98.253(b)(1) of...)(B) and § 98.253(b)(1)(iii)(C), you must use the default CO2 emission factors for coke oven gas and...

Disposal of historically contaminated soil in the cement industry and the evaluation of environmental performance.

PubMed

Li, Yeqing; Zhang, Jiang; Miao, Wenjuan; Wang, Huanzhong; Wei, Mao

2015-09-01

Approximately 400000t of DDTs/HCHs-contaminated soil (CS) needed to be co-processed in a cement kiln with a time limitation of 2y. A new pre-processing facility with a "drying, grinding and DDTs/HCHs vaporizing" ability was equipped to meet the technical requirements for processing cement raw meal and the environmental standards for stack emissions. And the bottom of the precalciner with high temperatures >1000°C was chosen as the CS feeding point for co-processing, which has rarely been reported. To assess the environmental performance of CS pre- and co-processing technologies, according to the local regulation, a test burn was performed by independent and accredited institutes systematically for determination of the clinker quality, kiln stack gas emissions and destruction efficiency of the pollutant. The results demonstrated that the clinker was of high quality and not adversely affected by CS co-processing. Stack emissions were all below the limits set by Chinese standards. Particularly, PCDD/PCDF emissions ranged from 0.0023 to 0.0085ngI-TEQNm(-3). The less toxic OCDD was the peak congener for CS co-processing procedure, while the most toxic congeners (i.e. 2,3,7,8-TeCDD, 1,2,3,7,8-PeCDD and 2,3,4,7,8-PeCDD) remained in a minor proportion. Destruction and removal efficiency (DRE) and destruction efficiency (DE) of the kiln system were better than 99.9999% and 99.99%, respectively, at the highest CS feeding rate during normal production. To guarantee the environmental performance of the system the quarterly stack gas emission was also monitored during the whole period. And all of the results can meet the national standards requirements. Copyright © 2015 Elsevier Ltd. All rights reserved.

40 CFR 75.57 - General recordkeeping provisions.

Code of Federal Regulations, 2014 CFR

2014-07-01

... stack gas (percent H2O, rounded to the nearest tenth). If the continuous moisture monitoring system... record daily the following information for CO2 mass emissions: (i) Date; (ii) Daily combustion-formed CO2... whether optional procedure to adjust combustion-formed CO2 mass emissions for carbon retained in flyash...

40 CFR 75.57 - General recordkeeping provisions.

Code of Federal Regulations, 2013 CFR

2013-07-01

... stack gas (percent H2O, rounded to the nearest tenth). If the continuous moisture monitoring system... record daily the following information for CO2 mass emissions: (i) Date; (ii) Daily combustion-formed CO2... whether optional procedure to adjust combustion-formed CO2 mass emissions for carbon retained in flyash...

40 CFR 75.57 - General recordkeeping provisions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... stack gas (percent H2O, rounded to the nearest tenth). If the continuous moisture monitoring system... record daily the following information for CO2 mass emissions: (i) Date; (ii) Daily combustion-formed CO2... whether optional procedure to adjust combustion-formed CO2 mass emissions for carbon retained in flyash...

40 CFR 75.57 - General recordkeeping provisions.

Code of Federal Regulations, 2012 CFR

2012-07-01

... stack gas (percent H2O, rounded to the nearest tenth). If the continuous moisture monitoring system... record daily the following information for CO2 mass emissions: (i) Date; (ii) Daily combustion-formed CO2... whether optional procedure to adjust combustion-formed CO2 mass emissions for carbon retained in flyash...

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aravena, M.; Wagg, J.; Papadopoulos, P. P.

We report the detection of the {sup 12}CO J = 1-0 emission line in [H89]1821+643, one of the most optically luminous quasi-stellar objects (QSOs) in the local universe, and a template ULIRG-to-QSO transition object, located in a rich, cool-core cluster at z = 0.297. The CO emission is likely to be extended, highly asymmetric with respect to the center of the host elliptical where the QSO resides, and correspond with a molecular gas mass of {approx}8.0 x 10{sup 9} M{sub sun}. The dynamical mass enclosed by the CO emission-line region could amount to {approx}1.7 x 10{sup 12} M{sub sun} (80%more » of the total mass of the elliptical host). The bulk of the CO emission is located at {approx}9 kpc southeast from the nuclei position, close to a faint optical structure, suggesting that the CO emission could either represent a gas-rich companion galaxy merging with the elliptical host or a tail-like structure reminiscent of a previous interaction. We argue that the first scenario is more likely given the large masses implied by the CO source, which would imply a highly asymmetric elliptical host. The close alignment between the CO emission's major axis and the radio plume suggests a possible role in the excitation of the ambient gas reservoir by the latter. The stacking technique was used to search for CO emission and 3-mm continuum emission from galaxies in the surrounding cluster. However, no detection was found toward individual galaxies or the stacked ensemble of galaxies, with a 3{sigma} limit of <1.1 x 10{sup 9} M{sub sun} for the molecular gas.« less

Steam generation and pollution control system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jackson, D.H.

1979-02-13

The heat and flu gases which are ordinarily expelled through an emission stack of a conventional furnace are instead channeled through a heat exchanger to produce steam for power generation and are subsequently directed through a gas scrubber apparatus to remove all contaminates from the flu gas prior to expelling the gases into atmosphere.

KEY COMPARISON Final report on international comparison CCQM-K71: Measurement of stack gas

NASA Astrophysics Data System (ADS)

Nieuwenkamp, G.; van der Veen, A. M. H.; Wessel, R. M.; Qiao, Han; Oh, Sang-Hyub; Kim, Byung-Moon; Kim, Kwang-Sub; Pérez Castorena, Alejandro; Ramírez Nambo, Carlos; Koelliker Delgado, Jorge; Serrano Caballero, Victor M.; Rangel Murillo, Francisco; Avila Salas, Manuel de Jesus; Dias, Florbela; Baptista, Gonçalo; Konopelko, L. A.; Kustikov, Y. A.; Pankratov, V. V.; Selyukov, D. N.; Balandovich, V. S.; Vishnyakov, I. M.; Pavlov, M. V.; Maltsev, M. A.; Botha, Angelique; Valkova, Miroslava; Stovcik, Viliam; Musil, Stanislav; Milton, M. J. T.; Uprichard, I. J.; Vargha, G. M.; Guenther, F.; Gameson, L.; da Cunha, V.

2010-01-01

Industrial stack gas emission measurements are important for process control, control of air pollution, and for implementing legislation regarding carbon dioxide emission rights. Measurements are typically performed using a range of process analysers for carbon monoxide (CO), carbon dioxide (CO2), nitrogen oxides (NOx), sulphur dioxide (SO2) and miscellaneous hydrocarbons. The calibration of these analysers is often performed using a series of binary mixtures of each component in nitrogen. For reasons of efficiency as well as a better match with true stack gas, the use of multi-component mixtures for this purpose would be preferred. The aim of this key comparison is to evaluate the measurement capabilities of national metrology institutes for carbon monoxide, carbon dioxide, nitrogen monoxide, sulphur dioxide and propane in nitrogen. Ten laboratories participated in the key comparison and one in the associated study. The key comparison reference value is based on the gravimetric preparation data. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

Effective pollutant emission heights for atmospheric transport modelling based on real-world information.

PubMed

Pregger, Thomas; Friedrich, Rainer

2009-02-01

Emission data needed as input for the operation of atmospheric models should not only be spatially and temporally resolved. Another important feature is the effective emission height which significantly influences modelled concentration values. Unfortunately this information, which is especially relevant for large point sources, is usually not available and simple assumptions are often used in atmospheric models. As a contribution to improve knowledge on emission heights this paper provides typical default values for the driving parameters stack height and flue gas temperature, velocity and flow rate for different industrial sources. The results were derived from an analysis of the probably most comprehensive database of real-world stack information existing in Europe based on German industrial data. A bottom-up calculation of effective emission heights applying equations used for Gaussian dispersion models shows significant differences depending on source and air pollutant and compared to approaches currently used for atmospheric transport modelling.

Relationships between energy release, fuel mass loss, and trace gas and aerosol emissions during laboratory biomass fires

Treesearch

Patrick H. Freeborn; Martin J. Wooster; Wei Min Hao; Cecily A. Nordgren Ryan; Stephen P. Baker; Charles Ichoku

2008-01-01

Forty-four small-scale experimental fires were conducted in a combustion chamber to examine the relationship between biomass consumption, smoke production, convective energy release, and middle infrared (MIR) measurements of fire radiative energy (FRE). Fuel bed weights, trace gas and aerosol particle concentrations, stack flow rate and temperature, and concurrent...

Air pollution from gas flaring: new emission factor estimates and detection in a West African aerosol remote-sensing climatology

NASA Astrophysics Data System (ADS)

MacKenzie, Rob; Fawole, Olusegun Gabriel; Levine, James; Cai, Xiaoming

2016-04-01

Gas flaring, the disposal of gas through stacks in an open-air flame, is a common feature in the processing of crude oil, especially in oil-rich regions of the world. Gas flaring is a prominent source of volatile organic compounds (VOCs), polycyclic aromatic hydrocarbons (PAH), CO, CO2, nitrogen oxides (NOx), SO2 (in "sour" gas only), and soot (black carbon), as well as the release of locally significant amounts of heat. The rates of emission of these pollutants from gas flaring depend on a number of factors including, but not limited to, fuel composition and quantity, stack geometry, flame/combustion characteristics, and prevailing meteorological conditions. Here, we derive new estimated emission factors (EFs) for carbon-containing pollutants (excluding PAH). The air pollution dispersion model, ADMS5, is used to simulate the dispersion of the pollutants from flaring stacks in the Niger delta. A seasonal variation of the dispersion pattern of the pollutant within a year is studied in relation to the movements of the West Africa Monsoon (WAM) and other prevailing meteorological factors. Further, we have clustered AERONET aerosol signals using trajectory analysis to identify dominant aerosol sources at the Ilorin site in West Africa (4.34 oE, 8.32 oN). A 10-year trajectory-based analysis was undertaken (2005-2015, excluding 2010). Of particular interest are air masses that have passed through the gas flaring region in the Niger Delta area en-route the AERONET site. 7-day back trajectories were calculated using the UK Universities Global Atmospheric Modelling Programme (UGAMP) trajectory model which is driven by analyses from the European Centre for Medium-Range Weather Forecasts (ECMWF). From the back-trajectory calculations, dominant sources are identified, using literature classifications: desert dust (DD); Biomass burning (BB); and Urban-Industrial (UI). We use a combination of synoptic trajectories and aerosol optical properties to distinguish a fourth source: that due to gas flaring. We discuss the relative impact of these different aerosol sources on the overall radiative forcing at Ilorin AERONET site.

Polychlorinated dibenzo-p-dioxin and dibenzofuran and polychlorinated biphenyl emissions from different smelting stages in secondary copper metallurgy.

PubMed

Hu, Jicheng; Zheng, Minghui; Nie, Zhiqiang; Liu, Wenbin; Liu, Guorui; Zhang, Bing; Xiao, Ke

2013-01-01

Secondary copper production has received much attention for its high emissions of polychlorinated dibenzo-p-dioxin and dibenzofuran (PCDD/F) reported in previous studies. These studies focused on the estimation of total PCDD/F and polychlorinated biphenyl (PCB) emissions from secondary copper smelters. However, large variations in PCDD/F and PCB emissions reported in these studies were not analyzed and discussed further. In this study, stack gas samples at different smelting stages (feeding-fusion, oxidation and deoxidization) were collected from four plants to investigate variations in PCDD/F and PCB emissions and characteristics during the secondary copper smelting process. The results indicate that PCDD/F emissions occur mainly at the feeding-fusion stage and these emissions contribute to 54-88% of the total emissions from the secondary copper smelting process. The variation in feed material and operating conditions at different smelting stages leads to the variation in PCDD/F emissions during the secondary copper smelting process. The total PCDD/F and PCB discharge (stack gas emission+fly ash discharge) is consistent with the copper scrap content in the raw material in the secondary copper smelters investigated. On a production basis of 1 ton copper, the total PCDD/F and dl-PCB discharge was 102, 24.8 and 5.88 μg TEQ t(-1) for the three plants that contained 100%, 30% and 0% copper scrap in their raw material feed, respectively. Copyright © 2012 Elsevier Ltd. All rights reserved.

Performance of PEM fuel cells stack as affected by number of cell and gas flow-rate

NASA Astrophysics Data System (ADS)

Syampurwadi, A.; Onggo, H.; Indriyati; Yudianti, R.

2017-03-01

The proton exchange membrane fuel cell (PEMFC) is a promising technology as an alternative green energy due to its high power density, low operating temperatures, low local emissions, quiet operation and fast start up-shutdown. In order to apply fuel cell as portable power supply, the performance investigation of small number of cells is needed. In this study, PEMFC stacks consisting of 1, 3, 5 and 7-cells with an active area of 25 cm2 per cell have been designed and developed. Their was evaluated in variation of gas flow rate. The membrane electrode assembly (MEA) was prepared by hot-pressing commercial gas diffusion electrodes (Pt loading 0.5 mg/cm2) on pre-treated Nafion 117 membrane. The stacks were constructed using bipolar plates in serpentine pattern and Z-type gas flow configuration. The experimental results were presented as polarization and power output curves which show the effects of varying number of cells and H2/O2 flow-rates on the PEMFC performance. The experimental results showed that not only number of cells and gas flow-rates affected the fuel cells performance, but also the operating temperature as a result of electrochemistry reaction inside the cell.

Environmental assessment of a watertube boiler firing a coal-water slurry. Volume 2. Data supplement. Final report, January 1984-March 1985

DOE Office of Scientific and Technical Information (OSTI.GOV)

DeRosier, R.; Waterland, L.R.

1986-02-01

This report is a compendium of detailed test sampling and analysis data obtained in field tests of a watertube industrial boiler burning a coal/water slurry (CWS). Test data reported include preliminary stack test data, boiler operating data, and complete flue-gas emission results. Flue-gas emission measurements included continuous monitoring for criteria pollutants; onsite gas chromatography (GC) for volatile hydrocarbons (Cl-C6); Methods 5/8 sampling for particulate, SO/sub 2/, and SO/sub 3/ emissions; source assessment sampling system (SASS) for total organics in two boiling point ranges (100 to 300 C and > 300 C), organic compound category information using infrared spectrometry (IR), liquidmore » column (LC) chromatography separation, and low-resolution mass spectrometry (LRMS), specific quantitation of the semivolatile organic priority pollutants using gas chromatography/mass spectrometry (GC/MS), and trace-element emissions using spark-source mass spectrometry (SSMS) and atomic absorption spectroscopy (AAS); N/sub 2/O emissions by gas chromatography/electron-capture detector (GC/ECD); and biological assay testing of SASS and ash-stream samples.« less

Dioxins, furans and polycyclic aromatic hydrocarbons emissions from a hospital and cemetery waste incinerator

NASA Astrophysics Data System (ADS)

Mininni, Giuseppe; Sbrilli, Andrea; Maria Braguglia, Camilla; Guerriero, Ettore; Marani, Dario; Rotatori, Mauro

An experimental campaign was carried out on a hospital and cemetery waste incineration plant in order to assess the emissions of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and polycyclic aromatic hydrocarbons (PAHs). Raw gases were sampled in the afterburning chamber, using a specifically designed device, after the heat recovery section and at the stack. Samples of slags from the combustion chamber and fly ashes from the bag filter were also collected and analyzed. PCDD/Fs and PAHs concentrations in exhaust gas after the heat exchanger (200-350 °C) decreased in comparison with the values detected in the afterburning chamber. Pollutant mass balance regarding the heat exchanger did not confirm literature findings about the de novo synthesis of PCDD/Fs in the heat exchange process. In spite of a consistent reduction of PCDD/Fs in the flue gas treatment system (from 77% up to 98%), the limit of 0.1 ng ITEQ Nm -3 at the stack was not accomplished. PCDD/Fs emission factors for air spanned from 2.3 up to 44 μg ITEQ t -1 of burned waste, whereas those through solid residues (mainly fly ashes) were in the range 41-3700 μg ITEQ t -1. Tests run with cemetery wastes generally showed lower PCDD/F emission factors than those with hospital wastes. PAH total emission factors (91-414 μg kg -1 of burned waste) were in the range of values reported for incineration of municipal and industrial wastes. In spite of the observed release from the scrubber, carcinogenic PAHs concentrations at the stack (0.018-0.5 μg Nm -3) were below the Italian limit of 10 μg Nm -3.

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

Under contract with the US Department of Energy (DE-AC22-92PCO0367), Pittsburgh Energy Technology Center, Radian Corporation has conducted a test program to collect and analyze size-fractionated stack gas particulate samples for selected inorganic hazardous air pollutants (HAPS). Specific goals of the program are (1) the collection of one-gram quantities of size-fractionated stack gas particulate matter for bulk (total) and surface chemical charactization, and (2) the determination of the relationship between particle size, bulk and surface (leachable) composition, and unit load. The information obtained from this program identifies the effects of unit load, particle size, and wet FGD system operation on themore » relative toxicological effects of exposure to particulate emissions.« less

The Case for Natural Gas Fueled Solid Oxide Fuel Cell Power Systems for Distributed Generation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chick, Lawrence A.; Weimar, Mark R.; Whyatt, Greg A.

2015-02-01

Natural-gas-fueled solid oxide fuel cell (NGSOFC) power systems yield electrical conversion efficiencies exceeding 60% and may become a viable alternative for distributed generation (DG) if stack life and manufacturing economies of scale can be realized. Currently, stacks last approximately 2 years and few systems are produced each year because of the relatively high cost of electricity from the systems. If mass manufacturing (10,000 units per year) and a stack life of 15 years can be reached, the cost of electricity from an NGSOFC system is estimated to be about 7.7 ¢/kWh, well within the price of commercial and residential retailmore » prices at the national level (9.9-10¢/kWh and 11-12 ¢/kWh, respectively). With an additional 5 ¢/kWh in estimated additional benefits from DG, NGSOFC could be well positioned to replace the forecasted 59-77 gigawatts of capacity loss resulting from coal plant closures due to stricter emissions regulations and low natural gas prices.« less

242-A Evaporator/plutonium uranium extraction (PUREX) effluent treatment facility (ETF) nonradioactive air emission test report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hill, J.S., Westinghouse Hanford

1996-05-10

This report shows the methods used to test the stack gas outlet concentration and emission rate of Volatile Organic Compounds as Total Non-Methane Hydrocarbons in parts per million by volume,grams per dry standard cubic meter, and grams per minute from the PUREX ETF stream number G6 on the Hanford Site. Test results are shown in Appendix B.1.

Aged particles derived from emissions of coal-fired power plants: The TERESA field results

PubMed Central

Kang, Choong-Min; Gupta, Tarun; Ruiz, Pablo A.; Wolfson, Jack M.; Ferguson, Stephen T.; Lawrence, Joy E.; Rohr, Annette C.; Godleski, John; Koutrakis, Petros

2013-01-01

The Toxicological Evaluation of Realistic Emissions Source Aerosols (TERESA) study was carried out at three US coal-fired power plants to investigate the potential toxicological effects of primary and photochemically aged (secondary) particles using in situ stack emissions. The exposure system designed successfully simulated chemical reactions that power plant emissions undergo in a plume during transport from the stack to receptor areas (e.g., urban areas). Test atmospheres developed for toxicological experiments included scenarios to simulate a sequence of atmospheric reactions that can occur in a plume: (1) primary emissions only; (2) H2SO4 aerosol from oxidation of SO2; (3) H2SO4 aerosol neutralized by gas-phase NH3; (4) neutralized H2SO4 with secondary organic aerosol (SOA) formed by the reaction of α-pinene with O3; and (5) three control scenarios excluding primary particles. The aged particle mass concentrations varied significantly from 43.8 to 257.1 μg/m3 with respect to scenario and power plant. The highest was found when oxidized aerosols were neutralized by gas-phase NH3 with added SOA. The mass concentration depended primarily on the ratio of SO2 to NOx (particularly NO) emissions, which was determined mainly by coal composition and emissions controls. Particulate sulfate (H2SO4 + neutralized sulfate) and organic carbon (OC) were major components of the aged particles with added SOA, whereas trace elements were present at very low concentrations. Physical and chemical properties of aged particles appear to be influenced by coal type, emissions controls and the particular atmospheric scenarios employed. PMID:20462390

Modular fuel-cell stack assembly

DOEpatents

Patel, Pinakin [Danbury, CT; Urko, Willam [West Granby, CT

2008-01-29

A modular multi-stack fuel-cell assembly in which the fuel-cell stacks are situated within a containment structure and in which a gas distributor is provided in the structure and distributes received fuel and oxidant gases to the stacks and receives exhausted fuel and oxidant gas from the stacks so as to realize a desired gas flow distribution and gas pressure differential through the stacks. The gas distributor is centrally and symmetrically arranged relative to the stacks so that it itself promotes realization of the desired gas flow distribution and pressure differential.

Characteristics of dioxin emissions at startup and shutdown of MSW incinerators.

PubMed

Tejima, Hajime; Nishigaki, Masahide; Fujita, Yasuyuki; Matsumoto, Akihiro; Takeda, Nobuo; Takaoka, Masaki

2007-01-01

Dioxin concentrations from municipal waste incinerators in Japan and elsewhere often show low concentrations that comply with legal limits (in this paper, the term "dioxin" designates WHO-TEQ: PCDD/Fs+dioxin-like PCB). However, such data is usually generated under normal steady state operational conditions, and there has been little investigation of releases occurring during startup and shutdown. It is important, therefore, to ascertain quantitatively emissions in an unsteady state (startup and shutdown) in order to correctly evaluate the relationship between emissions from a facility and the surrounding environment. The present study aimed to examine dioxin emissions of a continuously operated incinerator at startup and shutdown, and estimating the time period of greatest emission, and the processes causing dioxin generation. The startup process was divided into five stages and the shutdown into two; at each stage, dioxins in the flue gas were measured at the boiler outlet and the stack. From the concentration of dioxins and the flue gas volume at each stage, the amount of dioxins at startup and shutdown were calculated, and these were compared with that under steady state conditions. Dioxin concentration at the stack under steady state conditions was a very low level, while those at startup and shutdown were higher. In the case where dioxin concentration under a steady state is a low level like in this study, it is indicated that the total annual dioxin emission from a facility could be attributed to the startup periods.

Process test plan, phase II: waste retrieval sluicing system emissions collection

DOE Office of Scientific and Technical Information (OSTI.GOV)

POWERS, R.L.

1999-06-01

This Process Test Plan is prepared to continue from HNF-3733 which was Phase I of the test. Supplemental operational controls and sampling requirements are defined to safely obtain gas samples from the 296-C-006 ventilation system stack during active operation of the sluicing equipment.

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

Code of Federal Regulations, 2011 CFR

2011-07-01

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

SDSS IV MaNGA: Deep observations of extra-planar, diffuse ionized gas around late-type galaxies from stacked IFU spectra

NASA Astrophysics Data System (ADS)

Jones, A.; Kauffmann, G.; D'Souza, R.; Bizyaev, D.; Law, D.; Haffner, L.; Bahé, Y.; Andrews, B.; Bershady, M.; Brownstein, J.; Bundy, K.; Cherinka, B.; Diamond-Stanic, A.; Drory, N.; Riffel, R. A.; Sánchez, S. F.; Thomas, D.; Wake, D.; Yan, R.; Zhang, K.

2017-03-01

We have conducted a study of extra-planar diffuse ionized gas using the first year data from the MaNGA IFU survey. We have stacked spectra from 49 edge-on, late-type galaxies as a function of distance from the midplane of the galaxy. With this technique we can detect the bright emission lines Hα, Hβ, [O II]λλ3726, 3729, [O III]λ5007, [N II]λλ6549, 6584, and [S II]λλ6717, 6731 out to about 4 kpc above the midplane. With 16 galaxies we can extend this analysis out to about 9 kpc, I.e. a distance of 2Re, vertically from the midplane. In the halo, the surface brightnesses of the [O II] and Hα emission lines are comparable, unlike in the disk where Hα dominates. When we split the sample by specific star-formation rate, concentration index, and stellar mass, each subsample's emission line surface brightness profiles and ratios differ, indicating that extra-planar gas properties can vary. The emission line surface brightnesses of the gas around high specific star-formation rate galaxies are higher at all distances, and the line ratios are closer to ratios characteristic of H II regions compared with low specific star-formation rate galaxies. The less concentrated and lower stellar mass samples exhibit line ratios that are more like H II regions at larger distances than their more concentrated and higher stellar mass counterparts. The largest difference between different subsamples occurs when the galaxies are split by stellar mass. We additionally infer that gas far from the midplane in more massive galaxies has the highest temperatures and steepest radial temperature gradients based on their [N II]/Hα and [O II]/Hα ratios between the disk and the halo. SDSS IV.

Emission characteristics and vapour/particulate phase distributions of PCDD/F in a hazardous waste incinerator under transient conditions

PubMed Central

Wang, Chao; Cen, Kefa; Ni, Mingjiang; Li, Xiaodong

2018-01-01

Polychlorinated dibenzo-p-dioxin and polychlorinated dibenzofuran (PCDD/F) emission characteristics and vapour/particulate phase partitions under three continued operation conditions, i.e. shut-down, start-up and after start-up, were investigated by sampling stack gas. The results indicated that the PCDD/F emission levels were 0.40–18.03 ng I-TEQ Nm−3, much higher than the annual monitoring level (0.016 ng I-TEQ Nm−3). Additionally, the PCDD/F emission levels in start-up were higher than the other two conditions. Furthermore, the PCDD/F congener profiles differed markedly between shut-down and start-up, and the chlorination degree of PCDD/F increased in shut-down and decreased evidently in start-up. Moreover, PCDD/F vapour/particulate phase distributions varied significantly under three transient conditions. The PCDD/F vapour phase proportion decreased as the shut-down process continued, then increased as the start-up process proceeded, finally more than 98% of the PCDD/F congeners were distributed in the vapour phase after start-up. The correlations between log(Cv/Cs) versus log pL0 of each PCDD/F congener in stack gas were disorganized in shut-down, and trend to a linear distribution after start-up. Besides, polychlorinated biphenyl emissions show behaviour similar to that of PCDD/F, and the lower chlorinated congeners have a stronger relationship with 2,3,7,8-PCDD/Fs, such as M1CB and D2CB. PMID:29410821

Mercury Concentrations in Plant Tissues as Affected by FGDG Application to Soil

USDA-ARS?s Scientific Manuscript database

Flue Gas Desulfurization Gypsum (FGDG) is produced by reducing sulfur dioxide emissions from themo-electric coal-fired power plants. The most common practice of FGDG production may trap some of the Mercury (Hg) present in the coal that normally would escape as vapor in the stack gases. Concern for t...

Characterization of Coal Combustion Residues from Electric Utilities Using Wet Scrubbers for Multi-Pollutant Control

EPA Science Inventory

This report evaluates changes that may occur to coal combustion residues (CCRs) in response to changes in air pollution control technology at coal-fired power plants, which will reduce emissions from the flue gas stack by transferring pollutants to fly ash and other air pollution...

40 CFR 63.7296 - What emission limitations must I meet for battery stacks?

Code of Federal Regulations, 2010 CFR

2010-07-01

... for battery stacks? 63.7296 Section 63.7296 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY..., Quenching, and Battery Stacks Emission Limitations and Work Practice Standards § 63.7296 What emission limitations must I meet for battery stacks? You must not discharge to the atmosphere any emissions from any...

40 CFR 63.7296 - What emission limitations must I meet for battery stacks?

Code of Federal Regulations, 2013 CFR

2013-07-01

... for battery stacks? 63.7296 Section 63.7296 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY..., Quenching, and Battery Stacks Emission Limitations and Work Practice Standards § 63.7296 What emission limitations must I meet for battery stacks? You must not discharge to the atmosphere any emissions from any...

40 CFR 63.7296 - What emission limitations must I meet for battery stacks?

Code of Federal Regulations, 2011 CFR

2011-07-01

... for battery stacks? 63.7296 Section 63.7296 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY..., Quenching, and Battery Stacks Emission Limitations and Work Practice Standards § 63.7296 What emission limitations must I meet for battery stacks? You must not discharge to the atmosphere any emissions from any...

40 CFR 63.7296 - What emission limitations must I meet for battery stacks?

Code of Federal Regulations, 2012 CFR

2012-07-01

... for battery stacks? 63.7296 Section 63.7296 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY..., Quenching, and Battery Stacks Emission Limitations and Work Practice Standards § 63.7296 What emission limitations must I meet for battery stacks? You must not discharge to the atmosphere any emissions from any...

40 CFR 63.7296 - What emission limitations must I meet for battery stacks?

Code of Federal Regulations, 2014 CFR

2014-07-01

... for battery stacks? 63.7296 Section 63.7296 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY..., Quenching, and Battery Stacks Emission Limitations and Work Practice Standards § 63.7296 What emission limitations must I meet for battery stacks? You must not discharge to the atmosphere any emissions from any...

Concentrations and patterns of polychlorinated biphenyls at different process stages of cement kilns co-processing waste incinerator fly ash.

PubMed

Liu, Guorui; Yang, Lili; Zhan, Jiayu; Zheng, Minghui; Li, Li; Jin, Rong; Zhao, Yuyang; Wang, Mei

2016-12-01

Cement kilns can be used to co-process fly ash from municipal solid waste incinerators. However, this might increase emission of organic pollutants like polychlorinated biphenyls (PCBs). Knowledge of PCB concentrations and homolog and congener patterns at different stages in this process could be used to assess the possibility of simultaneously controlling emissions of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and "dioxin-like" compounds. To date, emissions from cement kilns co-processing fly ash from municipal solid waste incinerators have not been analyzed for PCBs. In this study, stack gas and particulate samples from two cement kilns co-processing waste incinerator fly ash were analyzed for PCBs. The average total tri- to deca-chlorinated biphenyl (∑ 3-10 PCB) concentration in the stack gas samples was 10.15ngm -3 . The ∑ 3-10 PCB concentration ranges in particulate samples from different stages were 0.83-41.79ngg -1 for cement kiln 1and0.13-1.69ngg -1 for cement kiln 2. The ∑ 3-10 PCB concentrations were much higher in particulate samples from the suspension pre-heater boiler, humidifier tower, and kiln back-end bag filters than in particulate samples from other stages. For these three stages, PCBs contributed to 15-18% of the total PCB, PCDD/F, and polychlorinated naphthalene toxic equivalents in stack gases and particulate matter. The PCB distributions were similar to those found in other studies for PCDD/Fs and polychlorinated naphthalenes, which suggest that it may be possible to simultaneously control emissions of multiple organic pollutants from cement kilns. Homolog patterns in the particulate samples were dominated by the pentachlorobiphenyls. CB-105, CB-118, and CB-123 were the dominant dioxin-like PCB congeners that formed at the back-end of the cement kiln. A mass balance of PCBs in the cement kilns indicated that the total mass of PCBs in the stack gases and clinker was about half the mass of PCBs in the raw materials. Copyright © 2016 Elsevier Ltd. All rights reserved.

Assessment and Optimization of the Accuracy of an Aircraft-Based Technique Used to Quantify Greenhouse Gas Emission Rates from Point Sources

NASA Astrophysics Data System (ADS)

Shepson, P. B.; Lavoie, T. N.; Kerlo, A. E.; Stirm, B. H.

2016-12-01

Understanding the contribution of anthropogenic activities to atmospheric greenhouse gas concentrations requires an accurate characterization of emission sources. Previously, we have reported the use of a novel aircraft-based mass balance measurement technique to quantify greenhouse gas emission rates from point and area sources, however, the accuracy of this approach has not been evaluated to date. Here, an assessment of method accuracy and precision was performed by conducting a series of six aircraft-based mass balance experiments at a power plant in southern Indiana and comparing the calculated CO2 emission rates to the reported hourly emission measurements made by continuous emissions monitoring systems (CEMS) installed directly in the exhaust stacks at the facility. For all flights, CO2 emissions were quantified before CEMS data were released online to ensure unbiased analysis. Additionally, we assess the uncertainties introduced to the final emission rate caused by our analysis method, which employs a statistical kriging model to interpolate and extrapolate the CO2 fluxes across the flight transects from the ground to the top of the boundary layer. Subsequently, using the results from these flights combined with the known emissions reported by the CEMS, we perform an inter-model comparison of alternative kriging methods to evaluate the performance of the kriging approach.

The assessment of health impacts and external costs of natural gas-fired power plant of Qom.

PubMed

Fouladi Fard, Reza; Naddafi, Kazem; Yunesian, Masud; Nabizadeh Nodehi, Ramin; Dehghani, Mohammad Hadi; Hassanvand, Mohammad Sadegh

2016-10-01

The external health damage costs of the combined cycle natural gas-fired power plant of Qom were investigated via the simplified impact pathway approach. Emitted particulate matter (PM 10 ) and gaseous pollutants (NO x , CO, and SO 2 ) from the power plant stack were measured The health effects and related costs were estimated by QUERI model from AirPacts according to the emissions, source and stack parameters, pollutant depletion velocities, exposure-response functions, local and regional population density, and detailed meteorological data. The results showed that the main health effect was assigned to the nitrate as restricted activity days (RAD) with 25,240 days/year. For all pollutants, the maximum health damage costs were related to the long-term mortality (49 %), restricted activity days (27 %), and chronic bronchitis (21 %). The annual health damage costs were approximately 4.76 million US$, with the cost being 0.096 US per kWh of generating electricity. Although the health damage costs of gas-fired power plant were lower than those of other heavy fuels, it seems essential to consider the health and environmental damages and focus on the emission control strategies, particularly in site selection for the new power plants and expanding the current ones.

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

... the hourly stack flow rate (in scfh). Only one methodology for determining NOX mass emissions shall be...-diluent continuous emissions monitoring system and a flow monitoring system in the common stack, record... maintain a flow monitoring system and diluent monitor in the duct to the common stack from each unit; or...

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gottesfeld, S.

The fuel cell is the most efficient device for the conversion of hydrogen fuel to electric power. As such, the fuel cell represents a key element in efforts to demonstrate and implement hydrogen fuel utilization for electric power generation. The low temperature, polymer electrolyte membrane fuel cell (PEMFC) has recently been identified as an attractive option for stationary power generation, based on the relatively simple and benign materials employed, the zero-emission character of the device, and the expected high power density, high reliability and low cost. However, a PEMFC stack fueled by hydrogen with the combined properties of low cost,more » high performance and high reliability has not yet been demonstrated. Demonstration of such a stack will remove a significant barrier to implementation of this advanced technology for electric power generation from hydrogen. Work done in the past at LANL on the development of components and materials, particularly on advanced membrane/electrode assemblies (MEAs), has contributed significantly to the capability to demonstrate in the foreseeable future a PEMFC stack with the combined characteristics described above. A joint effort between LANL and an industrial stack manufacturer will result in the demonstration of such a fuel cell stack for stationary power generation. The stack could operate on hydrogen fuel derived from either natural gas or from renewable sources. The technical plan includes collaboration with a stack manufacturer (CRADA). It stresses the special requirements from a PEMFC in stationary power generation, particularly maximization of the energy conversion efficiency, extension of useful life to the 10 hours time scale and tolerance to impurities from the reforming of natural gas.« less

An ALMA Survey of CO Isotopologue Emission from Protoplanetary Disks in Chamaeleon I

DOE Office of Scientific and Technical Information (OSTI.GOV)

Long Feng; Herczeg, Gregory J.; Pascucci, Ilaria

The mass of a protoplanetary disk limits the formation and future growth of any planet. Masses of protoplanetary disks are usually calculated from measurements of the dust continuum emission by assuming an interstellar gas-to-dust ratio. To investigate the utility of CO as an alternate probe of disk mass, we use ALMA to survey {sup 13}CO and C{sup 18}O J = 3–2 line emission from a sample of 93 protoplanetary disks around stars and brown dwarfs with masses from in the nearby Chamaeleon I star-forming region. We detect {sup 13}CO emission from 17 sources and C{sup 18}O from only one source.more » Gas masses for disks are then estimated by comparing the CO line luminosities to results from published disk models that include CO freeze-out and isotope-selective photodissociation. Under the assumption of a typical interstellar medium CO-to-H{sub 2} ratio of 10{sup −4}, the resulting gas masses are implausibly low, with an average gas mass of ∼0.05 M {sub Jup} as inferred from the average flux of stacked {sup 13}CO lines. The low gas masses and gas-to-dust ratios for Cha I disks are both consistent with similar results from disks in the Lupus star-forming region. The faint CO line emission may instead be explained if disks have much higher gas masses, but freeze-out of CO or complex C-bearing molecules is underestimated in disk models. The conversion of CO flux to CO gas mass also suffers from uncertainties in disk structures, which could affect gas temperatures. CO emission lines will only be a good tracer of the disk mass when models for C and CO depletion are confirmed to be accurate.« less

An ALMA Survey of CO Isotopologue Emission from Protoplanetary Disks in Chamaeleon I

NASA Astrophysics Data System (ADS)

Long, Feng; Herczeg, Gregory J.; Pascucci, Ilaria; Drabek-Maunder, Emily; Mohanty, Subhanjoy; Testi, Leonardo; Apai, Daniel; Hendler, Nathan; Henning, Thomas; Manara, Carlo F.; Mulders, Gijs D.

2017-08-01

The mass of a protoplanetary disk limits the formation and future growth of any planet. Masses of protoplanetary disks are usually calculated from measurements of the dust continuum emission by assuming an interstellar gas-to-dust ratio. To investigate the utility of CO as an alternate probe of disk mass, we use ALMA to survey 13CO and C18O J = 3–2 line emission from a sample of 93 protoplanetary disks around stars and brown dwarfs with masses from in the nearby Chamaeleon I star-forming region. We detect 13CO emission from 17 sources and C18O from only one source. Gas masses for disks are then estimated by comparing the CO line luminosities to results from published disk models that include CO freeze-out and isotope-selective photodissociation. Under the assumption of a typical interstellar medium CO-to-H2 ratio of 10‑4, the resulting gas masses are implausibly low, with an average gas mass of ∼0.05 M Jup as inferred from the average flux of stacked 13CO lines. The low gas masses and gas-to-dust ratios for Cha I disks are both consistent with similar results from disks in the Lupus star-forming region. The faint CO line emission may instead be explained if disks have much higher gas masses, but freeze-out of CO or complex C-bearing molecules is underestimated in disk models. The conversion of CO flux to CO gas mass also suffers from uncertainties in disk structures, which could affect gas temperatures. CO emission lines will only be a good tracer of the disk mass when models for C and CO depletion are confirmed to be accurate.

Cooler and particulate separator for an off-gas stack

DOEpatents

Wright, George T.

1992-01-01

An off-gas stack for a melter comprising an air conduit leading to two sets of holes, one set injecting air into the off-gas stack near the melter plenum and the second set injecting air downstream of the first set. The first set injects air at a compound angle, having both downward and tangential components, to create a reverse vortex flow, counter to the direction of flow of gas through the stack and also along the periphery of the stack interior surface. Air from the first set of holes pervents recirculation zones from forming and the attendant accumulation of particulate deposits on the wall of the stack and will also return to the plenum any particulate swept up in the gas entering the stack. The second set of holes injects air in the same direction as the gas in the stack to compensate for the pressure drop and to prevent the concentration of condensate in the stack. A set of sprayers, receiving water from a second conduit, is located downstream of the second set of holes and sprays water into the gas to further cool it.

40 CFR 75.16 - Special provisions for monitoring emissions from common, bypass, and multiple stacks for SO2...

Code of Federal Regulations, 2011 CFR

2011-07-01

... emissions from common, bypass, and multiple stacks for SO2 emissions and heat input determinations. 75.16... emissions from common, bypass, and multiple stacks for SO2 emissions and heat input determinations. (a... by the Administrator, such that these emissions are not underestimated. (e) Heat input rate. The...

40 CFR 75.16 - Special provisions for monitoring emissions from common, bypass, and multiple stacks for SO 2...

Code of Federal Regulations, 2013 CFR

2013-07-01

... emissions from common, bypass, and multiple stacks for SO 2 emissions and heat input determinations. 75.16... emissions from common, bypass, and multiple stacks for SO 2 emissions and heat input determinations. (a... by the Administrator, such that these emissions are not underestimated. (e) Heat input rate. The...

40 CFR 75.16 - Special provisions for monitoring emissions from common, bypass, and multiple stacks for SO2...

Code of Federal Regulations, 2012 CFR

2012-07-01

... emissions from common, bypass, and multiple stacks for SO2 emissions and heat input determinations. 75.16... emissions from common, bypass, and multiple stacks for SO2 emissions and heat input determinations. (a... by the Administrator, such that these emissions are not underestimated. (e) Heat input rate. The...

40 CFR 75.16 - Special provisions for monitoring emissions from common, bypass, and multiple stacks for SO 2...

Code of Federal Regulations, 2014 CFR

2014-07-01

... emissions from common, bypass, and multiple stacks for SO 2 emissions and heat input determinations. 75.16... emissions from common, bypass, and multiple stacks for SO 2 emissions and heat input determinations. (a... by the Administrator, such that these emissions are not underestimated. (e) Heat input rate. The...

Evaluation of nitrous oxide as a substitute for sulfur hexafluoride to reduce global warming impacts of ANSI/HPS N13.1 gaseous uniformity testing

NASA Astrophysics Data System (ADS)

Yu, Xiao-Ying; Barnett, J. Matthew; Amidan, Brett G.; Recknagle, Kurtis P.; Flaherty, Julia E.; Antonio, Ernest J.; Glissmeyer, John A.

2018-03-01

The ANSI/HPS N13.1-2011 standard requires gaseous tracer uniformity testing for sampling associated with stacks used in radioactive air emissions. Sulfur hexafluoride (SF6), a greenhouse gas with a high global warming potential, has long been the gas tracer used in such testing. To reduce the impact of gas tracer tests on the environment, nitrous oxide (N2O) was evaluated as a potential replacement to SF6. The physical evaluation included the development of a test plan to record percent coefficient of variance and the percent maximum deviation between the two gases while considering variables such as fan configuration, injection position, and flow rate. Statistical power was calculated to determine how many sample sets were needed, and computational fluid dynamic modeling was utilized to estimate overall mixing in stacks. Results show there are no significant differences between the behaviors of the two gases, and SF6 modeling corroborated N2O test results. Although, in principle, all tracer gases should behave in an identical manner for measuring mixing within a stack, the series of physical tests guided by statistics was performed to demonstrate the equivalence of N2O testing to SF6 testing in the context of stack qualification tests. The results demonstrate that N2O is a viable choice leading to a four times reduction in global warming impacts for future similar compliance driven testing.

Atmospheric occurrence and health risks of PCDD/Fs, polychlorinated biphenyls, and polychlorinated naphthalenes by air inhalation in metallurgical plants.

PubMed

Yang, Lili; Liu, Guorui; Zheng, Minghui; Jin, Rong; Zhu, Qingqing; Zhao, Yuyang; Zhang, Xian; Xu, Yang

2017-02-15

Metallurgical plants are important sources of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs) and polychlorinated naphthalenes (PCNs). It is significant to evaluate the air levels and human risks of PCDD/Fs, PCBs and PCNs in metallurgical plants considering their adverse effects on human health and thousands of metallurgical plants being in operation in China. The estimated inhalation intakes of PCDD/Fs, PCBs, and PCNs together in eight iron ore sintering plants, three secondary copper plants, four secondary aluminum plants, and one secondary lead plant were 4.9-213.4, 21.4-4026.4, 28.7-630, and 11.7fgTEQkg -1 day -1 , respectively, and the corresponding cancer risks were estimated to be 8.7×10 -7 to 3.8×10 -5 , 5.1×10 -6 to 1.1×10 -4 , 3.8×10 -6 to 7.1×10 -4 , and 2.1×10 -6 , respectively. The estimated cancer risk were higher than 100 per million people for three secondary aluminum and copper smelters among the sixteen metallurgical plants, indicating high cancer risks. Stack gas samples from metallurgical plants were also collected and analyzed for comparing their emission profiles with that of air samples. The comparison of PCDD/F, PCB and PCN profiles between air samples and stack gas samples by similarity calculation and principal component analysis suggested the influence of stack gas emissions from metallurgical plants on surrounding air. These results are helpful for understanding the exposure risk to PCDD/Fs, PCBs and PCNs in numerous metallurgical plants being operation in China. Copyright © 2016 Elsevier B.V. All rights reserved.

Sources of dioxins in the United Kingdom: the steel industry and other sources.

PubMed

Anderson, David R; Fisher, Raymond

2002-01-01

Several countries have compiled national inventories of dioxin (polychlorinated dibenzo-p-dioxin [PCDD] and polychlorinated dibenzofuran [PCDF]) releases that detail annual mass emission estimates for regulated sources. High temperature processes, such as commercial waste incineration and iron ore sintering used in the production of iron and steel, have been identified as point sources of dioxins. Other important releases of dioxins are from various diffuse sources such as bonfire burning and domestic heating. The PCDD/F inventory for emissions to air in the UK has decreased significantly from 1995 to 1998 because of reduced emissions from waste incinerators which now generally operate at waste gas stack emissions of 1 ng I-TEQ/Nm3 or below. The iron ore sintering process is the only noteworthy source of PCDD/Fs at integrated iron and steelworks operated by Corus (formerly British Steel plc) in the UK. The mean waste gas stack PCDD/F concentration for this process is 1,2 ng I-TEQ/Nm3 based on 94 measurements and it has been estimated that this results in an annual mass release of approximately 38 g I-TEQ per annum. Diffuse sources now form a major contribution to the UK inventory as PCDD/Fs from regulated sources have decreased, for example, the annual celebration of Bonfire Night on 5th November in the UK causes an estimated release of 30 g I-TEQ, similar to that emitted by five sinter plants in the UK.

Cooler and particulate separator for an off-gas stack

DOEpatents

Wright, G.T.

1991-04-08

This report describes an off-gas stack for a melter, furnace or reaction vessel comprising an air conduit leading to two sets of holes, one set injecting air into the off-gas stack near the melter plenum and the second set injecting air downstream of the first set. The first set injects air at a compound angle, having both downward and tangential components, to create a reverse vortex flow, counter to the direction of flow of gas through the stack and also along the periphery of the stack interior surface. Air from the first set of holes prevents recirculation zones from forming and the attendant accumulation of particulate deposits on the wall of the stack and will also return to the plenum any particulate swept up in the gas entering the stack. The second set of holes injects air in the same direction as the gas in the stack to compensate for the pressure drop and to prevent the concentration of condensate in the stack. A set of sprayers, receiving water from a second conduit, is located downstream of the second set of holes and sprays water into the gas to further cool it.

User's guide for RAM. Volume II. Data preparation and listings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Turner, D.B.; Novak, J.H.

1978-11-01

The information presented in this user's guide is directed to air pollution scientists having an interest in applying air quality simulation models. RAM is a method of estimating short-term dispersion using the Gaussian steady-state model. These algorithms can be used for estimating air quality concentrations of relatively nonreactive pollutants for averaging times from an hour to a day from point and area sources. The algorithms are applicable for locations with level or gently rolling terrain where a single wind vector for each hour is a good approximation to the flow over the source area considered. Calculations are performed for eachmore » hour. Hourly meteorological data required are wind direction, wind speed, temperature, stability class, and mixing height. Emission information required of point sources consists of source coordinates, emission rate, physical height, stack diameter, stack gas exit velocity, and stack gas temperature. Emission information required of area sources consists of southwest corner coordinates, source side length, total area emission rate and effective area source-height. Computation time is kept to a minimum by the manner in which concentrations from area sources are estimated using a narrow plume hypothesis and using the area source squares as given rather than breaking down all sources into an area of uniform elements. Options are available to the user to allow use of three different types of receptor locations: (1) those whose coordinates are input by the user, (2) those whose coordinates are determined by the model and are downwind of significant point and area sources where maxima are likely to occur, and (3) those whose coordinates are determined by the model to give good area coverage of a specific portion of the region. Computation time is also decreased by keeping the number of receptors to a minimum. Volume II presents RAM example outputs, typical run streams, variable glossaries, and Fortran source codes.« less

The galaxy cluster outskirts probed by Chandra

NASA Astrophysics Data System (ADS)

Morandi, Andrea; Sun, Ming; Forman, William; Jones, Christine

2015-08-01

Exploring the virialization region of galaxy clusters has recently raised the attention of the scientific community, offering a direct view of structure formation. In this talk, I will present recent results on the physical properties of the intracluster medium in the outer volumes of a sample of 320 clusters (0.056 3 keV) in the Chandra archive, with a total integration time of ~20 Ms. We stacked the emission measure profiles of the clusters to detect a signal out to R_{100}. We then measured the average emission measure, gas density and gas fraction, which scale according to the self-similar model of cluster formation. We observe a steepening of the density profiles beyond R_{500} with slope beta ~ 0.68 at R_{500} and beta ~ 1 at R_{200} and beyond. By tracking the direction of the cosmic filaments where the clusters are embedded, we report that galaxy clusters deviate from spherical symmetry. We also did not find evolution of the gas density with redshift, confirming the self-similar evolution of the gas density. The value of the baryon fraction reaches the cosmic value at R_{200}: however, systematics due to non-thermal pressure support and clumpiness might enhance the measured gas fraction, leading to an actual deficit of the baryon budget with respect to the primordial value). This novel method, the stacking the X-ray signal of cluster outskirts, has the capacity to provide a generational leap forward in our understanding of cluster physics and formation, and the use of clusters as cosmological probes.

Ram pressure stripping of hot coronal gas from group and cluster galaxies and the detectability of surviving X-ray coronae

NASA Astrophysics Data System (ADS)

Vijayaraghavan, Rukmani; Ricker, Paul M.

2015-05-01

Ram pressure stripping can remove hot and cold gas from galaxies in the intracluster medium, as shown by observations of X-ray and H I galaxy wakes in nearby clusters of galaxies. However, ram pressure stripping, including pre-processing in group environments, does not remove all the hot coronal gas from cluster galaxies. Recent high-resolution Chandra observations have shown that ˜1-4 kpc extended, hot galactic coronae are ubiquitous in group and cluster galaxies. To better understand this result, we simulate ram pressure stripping of a cosmologically motivated population of galaxies in isolated group and cluster environments. The galaxies and the host group and cluster are composed of collisionless dark matter and hot gas initially in hydrostatic equilibrium with the galaxy and host potentials. We show that the rate at which gas is lost depends on the galactic and host halo mass. Using synthetic X-ray observations, we evaluate the detectability of stripped galactic coronae in real observations by stacking images on the known galaxy centres. We find that coronal emission should be detected within ˜10 arcsec, or ˜5 kpc up to ˜2.3 Gyr in the lowest (0.1-1.2 keV) energy band. Thus, the presence of observed coronae in cluster galaxies significantly smaller than the hot X-ray haloes of field galaxies indicates that at least some gas removal occurs within cluster environments for recently accreted galaxies. Finally, we evaluate the possibility that existing and future X-ray cluster catalogues can be used in combination with optical galaxy positions to detect galactic coronal emission via stacking analysis. We briefly discuss the effects of additional physical processes on coronal survival, and will address them in detail in future papers in this series.

Multiscale observations of CO2, 13CO2, and pollutants at Four Corners for emission verification and attribution

PubMed Central

Lindenmaier, Rodica; Dubey, Manvendra K.; Henderson, Bradley G.; Butterfield, Zachary T.; Herman, Jay R.; Rahn, Thom; Lee, Sang-Hyun

2014-01-01

There is a pressing need to verify air pollutant and greenhouse gas emissions from anthropogenic fossil energy sources to enforce current and future regulations. We demonstrate the feasibility of using simultaneous remote sensing observations of column abundances of CO2, CO, and NO2 to inform and verify emission inventories. We report, to our knowledge, the first ever simultaneous column enhancements in CO2 (3–10 ppm) and NO2 (1–3 Dobson Units), and evidence of δ13CO2 depletion in an urban region with two large coal-fired power plants with distinct scrubbing technologies that have resulted in ∆NOx/∆CO2 emission ratios that differ by a factor of two. Ground-based total atmospheric column trace gas abundances change synchronously and correlate well with simultaneous in situ point measurements during plume interceptions. Emission ratios of ∆NOx/∆CO2 and ∆SO2/∆CO2 derived from in situ atmospheric observations agree with those reported by in-stack monitors. Forward simulations using in-stack emissions agree with remote column CO2 and NO2 plume observations after fine scale adjustments. Both observed and simulated column ∆NO2/∆CO2 ratios indicate that a large fraction (70–75%) of the region is polluted. We demonstrate that the column emission ratios of ∆NO2/∆CO2 can resolve changes from day-to-day variation in sources with distinct emission factors (clean and dirty power plants, urban, and fires). We apportion these sources by using NO2, SO2, and CO as signatures. Our high-frequency remote sensing observations of CO2 and coemitted pollutants offer promise for the verification of power plant emission factors and abatement technologies from ground and space. PMID:24843169

Characterization of polychlorinated dibenzo-p-dioxins and dibenzofurans, dioxin-like polychlorinated biphenyls, and polychlorinated naphthalenes in the environment surrounding secondary copper and aluminum metallurgical facilities in China.

PubMed

Hu, Jicheng; Zheng, Minghui; Liu, Wenbin; Nie, Zhiqiang; Li, Changliang; Liu, Guorui; Xiao, Ke

2014-10-01

Unintentionally produced persistent organic pollutants (UP-POPs) were determined in ambient air from around five secondary non-ferrous metal processing plants in China, to investigate the potential impacts of the emissions of these plants on their surrounding environments. The target compounds were polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), dioxin-like polychlorinated biphenyls (dl-PCBs), and polychlorinated naphthalenes (PCNs). The PCDD/F, dl-PCB, and PCN concentrations in the ambient air downwind of the plants were 4.70-178, 8.23-7520 and 152-4190 pg/m(3), respectively, and the concentrations upwind of the plants were lower. Clear correlations were found between ambient air and stack gas concentrations of the PCDD/Fs, dl-PCBs, and PCNs among the five plants, respectively. Furthermore, the UP-POPs homolog and congener patterns in the ambient air were similar to the patterns in the stack gas samples. These results indicate that UP-POPs emissions from the plants investigated have obvious impacts on the environments surrounding the plants. Copyright © 2014 Elsevier Ltd. All rights reserved.

New particle formation in the fresh flue-gas plume from a coal-fired power plant: effect of flue-gas cleaning

NASA Astrophysics Data System (ADS)

Mylläri, Fanni; Asmi, Eija; Anttila, Tatu; Saukko, Erkka; Vakkari, Ville; Pirjola, Liisa; Hillamo, Risto; Laurila, Tuomas; Häyrinen, Anna; Rautiainen, Jani; Lihavainen, Heikki; O'Connor, Ewan; Niemelä, Ville; Keskinen, Jorma; Dal Maso, Miikka; Rönkkö, Topi

2016-06-01

Atmospheric emissions, including particle number and size distribution, from a 726 MWth coal-fired power plant were studied experimentally from a power plant stack and flue-gas plume dispersing in the atmosphere. Experiments were conducted under two different flue-gas cleaning conditions. The results were utilized in a plume dispersion and dilution model taking into account particle formation precursor (H2SO4 resulted from the oxidation of emitted SO2) and assessment related to nucleation rates. The experiments showed that the primary emissions of particles and SO2 were effectively reduced by flue-gas desulfurization and fabric filters, especially the emissions of particles smaller than 200 nm in diameter. Primary pollutant concentrations reached background levels in 200-300 s. However, the atmospheric measurements indicated that new particles larger than 2.5 nm are formed in the flue-gas plume, even in the very early phases of atmospheric ageing. The effective number emission of nucleated particles were several orders of magnitude higher than the primary particle emission. Modelling studies indicate that regardless of continuing dilution of the flue gas, nucleation precursor (H2SO4 from SO2 oxidation) concentrations remain relatively constant. In addition, results indicate that flue-gas nucleation is more efficient than predicted by atmospheric aerosol modelling. In particular, the observation of the new particle formation with rather low flue-gas SO2 concentrations changes the current understanding of the air quality effects of coal combustion. The results can be used to evaluate optimal ways to achieve better air quality, particularly in polluted areas like India and China.

40 CFR 75.16 - Special provisions for monitoring emissions from common, bypass, and multiple stacks for SO2...

Code of Federal Regulations, 2010 CFR

2010-07-01

... maintain an SO2 continuous emission monitoring system and flow monitoring system in the duct to the common... emission monitoring system and flow monitoring system in the common stack and combine emissions for the... continuous emission monitoring system and flow monitoring system in the duct to the common stack from each...

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

A test program to collect and analyze size-fractionated stack gas particulate samples for selected inorganic hazardous air pollutants (HAPs) was conducted . Specific goals of the program are (1) the collection of one-gram quantities of size-fractionated stack gas particulate matter for bulk (total) and surface chemical characterization, and (2) the determination of the relationship between particle size, bulk and surface (leachable) composition, and unit load. The information obtained from this program identifies the effects of unit load, particle size, and wet FGD system operation on the relative toxicological effects of exposure to particulate emissions. Field testing was conducted in twomore » phases. The Phase I field program was performed over the period of August 24 through September 20, 1992, at the Tennessee Valley Authority Widows Creek Unit 8 Power Station, located near Stevenson (Jackson County), Alabama, on the Tennessee River. Sampling activities for Phase II were conducted from September 11 through October 14, 1993. Widows Creek Unit 8 is a 575-megawatt plant that uses bituminous coal averaging 3.7% sulfur and 13% ash. Downstream of the boiler, a venture wet scrubbing system is used for control of both sulfur dioxide and particulate emissions. There is no electrostatic precipitator (ESP) in this system. This system is atypical and represents only about 5% of the US utility industry. However, this site was chosen for this study because of the lack of information available for this particulate emission control system.« less

Stacking the Cosmic Web in fluorescent Ly α emission with MUSE

NASA Astrophysics Data System (ADS)

Gallego, Sofia G.; Cantalupo, Sebastiano; Lilly, Simon; Marino, Raffaella Anna; Pezzulli, Gabriele; Schaye, Joop; Wisotzki, Lutz; Bacon, Roland; Inami, Hanae; Akhlaghi, Mohammad; Tacchella, Sandro; Richard, Johan; Bouche, Nicolas F.; Steinmetz, Matthias; Carollo, Marcella

2018-04-01

Cosmological simulations suggest that most of the matter in the Universe is distributed along filaments connecting galaxies. Illuminated by the cosmic UV background (UVB), these structures are expected to glow in fluorescent Ly α emission with a surface brightness (SB) that is well below current limits for individual detections. Here, we perform a stacking analysis of the deepest MUSE/VLT data using three-dimensional regions (subcubes) with orientations determined by the position of neighbouring Ly α galaxies at 3 < z < 4. Our method increase the probability of detecting filamentary Ly α emission, provided that these structures are Lyman-limit systems (LLSs). By stacking 390 oriented subcubes we reach a 2σ sensitivity level of SB ≈ 0.44 × 10-20 erg s-1 cm-2 arcsec-2 in an aperture of 1 arcsec2 × 6.25 Å, three times below the expected fluorescent Ly α signal from the Haardt & Madau UVB at z ˜ 3.5. No detectable emission is found on intergalactic scales, implying that at least two thirds of our subcubes do not contain oriented LLSs. On the other hand, significant emission is detected in the circumgalactic medium (CGM) in the direction of the neighbours. The signal is stronger for galaxies with a larger number of neighbours and appears to be independent of any other galaxy properties. We estimate that preferentially oriented satellite galaxies cannot contribute significantly to this signal, suggesting instead that gas densities in the CGM are typically larger in the direction of neighbouring galaxies on cosmological scales.

Impact of Aircraft Emissions on Air Quality in the Vicinity of Airports. Volume I: Recent Airport Measurement Programs, Data Analyses, and Sub-Model Development

DTIC Science & Technology

1980-07-01

temperature has turbine stacks located in a region of high ambient turbu- - lence [Hoult (1975) and Egan (1975)]. I) I+ 110 4.5.4 Event Modeling Several...the aircraft industry in developing the gas turbine engine technology of the present era. Dispersion measurements permit determination of a power law...The ESEERCO Model for the Prediction of Plume Rise and Dispersion from Gas Turbine Engines. Air Pollution Control Association 68th Annual Meeting

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rao, Nageswara S.; Ramirez Aviles, Camila A.

We consider the problem of inferring the operational status of a reactor facility using measurements from a radiation sensor network deployed around the facility’s ventilation off-gas stack. The intensity of stack emissions decays with distance, and the sensor counts or measurements are inherently random with parameters determined by the intensity at the sensor’s location. We utilize the measurements to estimate the intensity at the stack, and use it in a one-sided Sequential Probability Ratio Test (SPRT) to infer on/off status of the reactor. We demonstrate the superior performance of this method over conventional majority fusers and individual sensors using (i)more » test measurements from a network of 21 NaI detectors, and (ii) effluence measurements collected at the stack of a reactor facility. We also analytically establish the superior detection performance of the network over individual sensors with fixed and adaptive thresholds by utilizing the Poisson distribution of the counts. We quantify the performance improvements of the network detection over individual sensors using the packing number of the intensity space.« less

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

... the affected units as the difference between NOX mass emissions measured in the common stack and NOX... emissions using the maximum potential NOX emission rate, the maximum potential flow rate, and either the maximum potential CO2 concentration or the minimum potential O2 concentration (as applicable). The maximum...

Probing Temperature Inside Planar SOFC Short Stack, Modules, and Stack Series

NASA Astrophysics Data System (ADS)

Yu, Rong; Guan, Wanbing; Zhou, Xiao-Dong

2017-02-01

Probing temperature inside a solid oxide fuel cell (SOFC) stack lies at the heart of the development of high-performance and stable SOFC systems. In this article, we report our recent work on the direct measurements of the temperature in three types of SOFC systems: a 5-cell short stack, a 30-cell stack module, and a stack series consisting of two 30-cell stack modules. The dependence of temperature on the gas flow rate and current density was studied under a current sweep or steady-state operation. During the current sweep, the temperature inside the 5-cell stack decreased with increasing current, while it increased significantly at the bottom and top of the 30-cell stack. During a steady-state operation, the temperature of the 5-cell stack was stable while it was increased in the 30-cell stack. In the stack series, the maximum temperature gradient reached 190°C when the gas was not preheated. If the gas was preheated and the temperature gradient was reduced to 23°C in the stack series with the presence of a preheating gas and segmented temperature control, this resulted in a low degradation rate.

Evaluation of nitrous oxide as a substitute for sulfur hexafluoride to reduce global warming impacts of ANSI/HPS N13.1 gaseous uniformity testing

DOE PAGES

Yu, Xiao-Ying; Barnett, J. Matthew; Amidan, Brett G.; ...

2017-12-12

The ANSI/HPS N13.1–2011 standard requires gaseous tracer uniformity testing for sampling associated with stacks used in radioactive air emissions. Sulfur hexafluoride (SF 6), a greenhouse gas with a high global warming potential, has long been the gas tracer used in such testing. To reduce the impact of gas tracer tests on the environment, nitrous oxide (N 2O) was evaluated as a potential replacement to SF 6. The physical evaluation included the development of a test plan to record percent coefficient of variance and the percent maximum deviation between the two gases while considering variables such as fan configuration, injection position,more » and flow rate. Statistical power was calculated to determine how many sample sets were needed, and computational fluid dynamic modeling was utilized to estimate overall mixing in stacks. Results show there are no significant differences between the behaviors of the two gases, and SF 6 modeling corroborated N 2O test results. Although, in principle, all tracer gases should behave in an identical manner for measuring mixing within a stack, the series of physical tests guided by statistics was performed to demonstrate the equivalence of N 2O testing to SF 6 testing in the context of stack qualification tests. In conclusion, the results demonstrate that N 2O is a viable choice leading to a four times reduction in global warming impacts for future similar compliance driven testing.« less

Evaluation of nitrous oxide as a substitute for sulfur hexafluoride to reduce global warming impacts of ANSI/HPS N13.1 gaseous uniformity testing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yu, Xiao-Ying; Barnett, J. Matthew; Amidan, Brett G.

The ANSI/HPS N13.1–2011 standard requires gaseous tracer uniformity testing for sampling associated with stacks used in radioactive air emissions. Sulfur hexafluoride (SF 6), a greenhouse gas with a high global warming potential, has long been the gas tracer used in such testing. To reduce the impact of gas tracer tests on the environment, nitrous oxide (N 2O) was evaluated as a potential replacement to SF 6. The physical evaluation included the development of a test plan to record percent coefficient of variance and the percent maximum deviation between the two gases while considering variables such as fan configuration, injection position,more » and flow rate. Statistical power was calculated to determine how many sample sets were needed, and computational fluid dynamic modeling was utilized to estimate overall mixing in stacks. Results show there are no significant differences between the behaviors of the two gases, and SF 6 modeling corroborated N 2O test results. Although, in principle, all tracer gases should behave in an identical manner for measuring mixing within a stack, the series of physical tests guided by statistics was performed to demonstrate the equivalence of N 2O testing to SF 6 testing in the context of stack qualification tests. In conclusion, the results demonstrate that N 2O is a viable choice leading to a four times reduction in global warming impacts for future similar compliance driven testing.« less

Propulsion Investigation for Zero and Near-Zero Emissions Aircraft

NASA Technical Reports Server (NTRS)

Snyder, Christopher A.; Berton, Jeffrey J.; Brown, Gerald v.; Dolce, James L.; Dravid, Marayan V.; Eichenberg, Dennis J.; Freeh, Joshua E.; Gallo, Christopher A.; Jones, Scott M.; Kundu, Krishna P.;

Communal biofuel burning for district heating: Emissions and immissions from medium-sized (0.4 and 1.5 MW) facilities

NASA Astrophysics Data System (ADS)

Fachinger, Friederike; Drewnick, Frank; Gieré, Reto; Borrmann, Stephan

2018-05-01

Particulate and gaseous emissions of two medium-sized district heating facilities (400 kW, fueled with miscanthus, and 1.5 MW, fueled with wood chips) were characterized for different operational conditions, and compared to previously obtained results for household wood and pellet stoves. SO2 and NOx emission factors (reported in mg MJFuel-1) were found to not only depend on fuel sulfur/nitrogen content, but also on combustion appliance type and efficiency. Emission factors of SO2, NOx, and PM (particulate matter) increased with increasing load. Particle chemical composition did not primarily depend on operational conditions, but varied mostly with combustion appliances, fuel types, and flue gas cleaning technologies. Black carbon content was decreasing with increasing combustion efficiency; chloride content was strongly enhanced when burning miscanthus. Flue gas cleaning using an electrostatic precipitator caused strong reduction not only in total PM, but also in the fraction of refractory and semi-refractory material within emitted PM1. For the impact of facilities on their surroundings (immissions) not only their total emissions are decisive, but also their stack heights. In immission measurements downwind of the two facilities, a plume could only be observed for the 400 kW facility with low (11 m) stack height (1.5 MW facility: 30 m), and measured immissions agreed reasonably well with predicted ones. The impact of these immissions is non-negligible: At a distance of 50 m from the facility, apart from CO2, also plume contributions of NOx, ultrafine particles, PM1, PM10, poly-aromatic hydrocarbons, and sulfate were detected, with enhancements above background values of 2-130%.

Radio Recombination Line Surveys of the inner Galactic Plane: SIGGMA and GDIGS

NASA Astrophysics Data System (ADS)

Liu, Bin; Anderson, Loren Dean; Luisi, Matteo; Balser, Dana; Bania, Thomas; Wenger, Trey; Haffner, Lawrence Matthew; Minchin, Robert; Roshi, Anish; Churchwell, Edward; Terzian, Yervant; McIntyre, Travis; Lebron, Mayra; SIGGMA team, GDIGS team

2018-01-01

Ionized gas is one of the primary components of the interstellar medium (ISM) and plays a crucial role in star formation and galaxy evolution. Radio recombination lines (RRLs) can directly trace ionized gas in HII regions and warm ionized medium (WIM) without being affected by interstellar extinction. Single-dish telescopes like Arecibo Observatory and the Green Bank Telescope (GBT) are sensitive to low surface brightness emission, and are therefore powerful tools for the study of HII regions and the WIM. We report here on two large surveys of RRL emission: The Survey of Ionized Gas in the Galaxy, Made with the Arecibo telescope (SIGGMA) and the GBT Diffuse Ionized Gas Survey (GDIGS). These are the first large-scale fully-sampled RRL surveys, and together cover nearly the entire first quadrant of the Galactic plane at ~arcmin spatial resolution (l = -5 - 32 deg. for GDIGS and l = 32 - 70 deg. for SIGGMA). SIGGMA is performed with the Arecibo L-band Feed Array (ALFA) receiver, whose bandpass covers twelve hydrogen alpha lines from H163α to H174α. By stacking the α-lines and smoothing to 4 km/s velocity resolution, the final SIGGMA spectra have a mean rms level of ~0.65 mJy per beam. The GDIGS data were taken with the GBT C-band receiver and the VEGAS backend and include RRLs from H95α to H117α, and when stacked and smoothed to 5 km/s resolution achieve 1 mJy per beam rms. Here, we report on early analysis of the SIGGMA and GDIGS data, and present first scientific results.

Simultaneous stack-gas scrubbing and waste water treatment

NASA Technical Reports Server (NTRS)

Poradek, J. C.; Collins, D. D.

1980-01-01

Simultaneous treatment of wastewater and S02-laden stack gas make both treatments more efficient and economical. According to results of preliminary tests, solution generated by stack gas scrubbing cycle reduces bacterial content of wastewater. Both processess benefit by sharing concentrations of iron.

Molecular Gas Reservoirs in Cluster Galaxies at z = 1.46

NASA Astrophysics Data System (ADS)

Hayashi, Masao; Tadaki, Ken-ichi; Kodama, Tadayuki; Kohno, Kotaro; Yamaguchi, Yuki; Hatsukade, Bunyo; Koyama, Yusei; Shimakawa, Rhythm; Tamura, Yoichi; Suzuki, Tomoko L.

2018-04-01

We present molecular gas reservoirs of 18 galaxies associated with the XMMXCS J2215.9–1738 cluster at z = 1.46. From Band 7 and Band 3 data of the Atacama Large Millimeter/submillimeter Array, we detect dust continuum emission at 870 μm and the CO J = 2–1 emission line from 8 and 17 member galaxies, respectively, within a clustercentric radius of R 200. The molecular gas masses derived from the CO and/or dust continuum luminosities show that the fraction of molecular gas mass and the depletion timescale for the cluster galaxies are larger than expected from the scaling relations of molecular gas on stellar mass and offset from the main sequence of star-forming galaxies in general fields. The galaxies closer to the cluster center in terms of both projected position and accretion phase seem to show a larger deviation from the scaling relations. We speculate that the environment of the galaxy cluster helps feed the gas through inflow to the member galaxies and reduce the efficiency of star formation. The stacked Band 3 spectrum of 12 quiescent galaxies with M stellar ∼ 1011 M ⊙ within 0.5R 200 shows no detection of a CO emission line, giving the upper limit of molecular gas mass and molecular gas fraction to be ≲1010 M ⊙ and ≲10%, respectively. Therefore, the massive galaxies in the cluster core quench the star formation activity while consuming most of the gas reservoirs.

Real-time monitoring of emissions from monoethanolamine-based industrial scale carbon capture facilities.

PubMed

Zhu, Liang; Schade, Gunnar Wolfgang; Nielsen, Claus Jørgen

2013-12-17

We demonstrate the capabilities and properties of using Proton Transfer Reaction time-of-flight mass spectrometry (PTR-ToF-MS) to real-time monitor gaseous emissions from industrial scale amine-based carbon capture processes. The benchmark monoethanolamine (MEA) was used as an example of amines needing to be monitored from carbon capture facilities, and to describe how the measurements may be influenced by potentially interfering species in CO2 absorber stack discharges. On the basis of known or expected emission compositions, we investigated the PTR-ToF-MS MEA response as a function of sample flow humidity, ammonia, and CO2 abundances, and show that all can exhibit interferences, thus making accurate amine measurements difficult. This warrants a proper sample pretreatment, and we show an example using a dilution with bottled zero air of 1:20 to 1:10 to monitor stack gas concentrations at the CO2 Technology Center Mongstad (TCM), Norway. Observed emissions included many expected chemical species, dominantly ammonia and acetaldehyde, but also two new species previously not reported but emitted in significant quantities. With respect to concerns regarding amine emissions, we show that accurate amine quantifications in the presence of water vapor, ammonia, and CO2 become feasible after proper sample dilution, thus making PTR-ToF-MS a viable technique to monitor future carbon capture facility emissions, without conventional laborious sample pretreatment.

Emissions of metals and polychlorinated dibenzo(p)dioxins and furans (PCDD/Fs) from Portland cement manufacturing plants: inter-kiln variability and dependence on fuel-types.

PubMed

Zemba, Stephen; Ames, Michael; Green, Laura; Botelho, Maria João; Gossman, David; Linkov, Igor; Palma-Oliveira, José

2011-09-15

Emissions from Portland cement manufacturing facilities may increase health risks in nearby populations and are thus subject to stringent regulations. Direct testing of pollutant concentrations in exhaust gases provides the best basis for assessing the extent of these risks. However, these tests (i) are often conducted under stressed, rather than typical, operating conditions, (ii) may be limited in number and duration, and (iii) may be influenced by specific fuel-types and attributes of individual kilns. We report here on the results of more than 150 emissions-tests conducted of two kilns at a Portland cement manufacturing plant in Portugal. The tests measured various regulated metals and polychlorinated dibenzo(p)dioxins and furans (PCDD/Fs). Stack-gas concentrations of pollutants were found to be highly variable, with standard deviations on the order of mean values. Emission rates of many pollutants were higher when coal was used as the main kiln fuel (instead of petroleum coke). Use of various supplemental fuels, however, had little effect on stack emissions, and few statistically significant differences were observed when hazardous waste was included in the fuel mix. Significant differences in emissions for some pollutants were observed between the two kilns despite their similar designs and uses of similar fuels. All measured values were found to be within applicable regulatory limits. Published by Elsevier B.V.

Molecular Gas in Obscured and Extremely Red Quasars at z ˜ 2.5

NASA Astrophysics Data System (ADS)

Alexandroff, Rachael; Zakamska, Nadia; Hamann, Fred; Greene, Jenny; Rahman, Mubdi

2018-01-01

Quasar feedback is a key element of modern galaxy evolution theory. During powerful episodes of feedback, quasar-driven winds are suspected of removing large amounts of molecular gas from the host galaxy, thus limiting supplies for star formation and ultimately curtailing the maximum mass of galaxies. Here we present Karl A. Jansky Very Large Array (VLA) observations of the CO(1-0) transition in 11 powerful obscured and extremely red quasars (ERQs) at z~2.5. Previous observations have shown that several of these targets display signatures of powerful quasar-driven winds in their ionized gas. Molecular emission is not detected in a single object, whether kinematically disturbed due to a quasar wind or in equilibrium with the host galaxy and neither is molecular gas detected in a combined stack of all objects (equivalent to an exposure time of over 10 hours with the VLA). This observation is in contrast with the previous suggestions that such objects should occupy gas-rich, extremely star-forming galaxies. Possible explanations include a paucity of molecular gas or an excess of high- excitation molecular gas, both of which could be the results of quasar feedback. In the radio continuum, we detect an average point-like (< 5 kpc) emission with luminosity νLν[33 GHz]=2.2 x 1042 erg s-1, consistent with optically-thin (α ≈ -1.0) synchrotron with some possible contribution from thermal free-free emission. The continuum radio emission of these radio-intermediate objects may be a bi-product of radiatively driven winds or may be due to weak jets confined to the host galaxy.

VOC removal and deodorization of effluent gases from an industrial plant by photo-oxidation, chemical oxidation, and ozonization.

PubMed

Domeño, Celia; Rodríguez-Lafuente, Angel; Martos, J M; Bilbao, Rafael; Nerín, Cristina

2010-04-01

The efficiency of photo-oxidation, chemical oxidation by sodium hypochlorite, and ozonization for the industrial-scale removal of volatile organic compounds (VOCs) and odors from gaseous emissions was studied by applying these treatments (in an experimental system) to substances passing through an emission stack of a factory producing maize derivatives. Absorption and ozonization were the most efficient treatment, removing 75% and 98% of VOCs, respectively, while photo-oxidation only removed about 59%. The emitted chemical compounds and odors were identified and quantified by gas chromatography-mass spectrometry (in full-scan mode). In addition to presenting the results, their implications for selecting optimal processes for treating volatile emissions are discussed.

DOE Office of Scientific and Technical Information (OSTI.GOV)

MacDonald, R.; Kelley, D.E.

In 1998, when Sunlaw Energy Corporation needed to retrofit their two natural gas fired power plants to meet new emissions requirements that were soon to come into place, they looked at existing technologies and found them either economically or environmentally undesirable. With the help of General Electric they developed a program of water injection that was capable of reducing the NO{sub x} emissions to 25 ppm. This, however, was not low enough to meet coming regulations. Sunlaw concluded that the best option for pollution control was to invert their own system. A partnership was formed between Sunlaw and Advanced Catalystmore » Systems, a catalyst development and manufacturing firm. The result of their efforts was Goal Line Environmental Technologies and the SCONOx catalytic absorption system. The newest SCONOx system, commissioned at Sunlaw's Federal cogeneration plant in December 1996, treats the exhaust of a GELM2500 gas turbine. Combined with water injection, it has reduced NO{sub x} emission from 160 ppm down to 1--2 ppm. Carbon monoxide emissions are virtually eliminated, with stack readings less than ambient levels. The SCONOx system uses single catalyst for both CO and NO{sub x} control. It oxidizes CO to CO{sub 2} and NO to NO{sub 2}, and the NO{sub 2} is then absorbed onto the surface of the catalyst. Just as a sponge absorbs water and must be periodically regenerated, the catalyst must be regenerated. This is accomplished by passing a dilute hydrogen gas across the surface of the catalyst in the absence of oxygen. Nitrogen oxygen are broken down into nitrogen and water, and this is exhausted up the stack instead of NO{sub x}. The SCONOx system is a breakthrough in CO and NO{sub x} control technology that makes it possible to have clean air without the use of ammonia or other hazardous materials. It is truly an environmentally friendly NO{sub x} system.« less

Evaluating emissions of HCHO, HONO, NO2, and SO2 from point sources using portable Imaging DOAS

NASA Astrophysics Data System (ADS)

Pikelnaya, O.; Tsai, C.; Herndon, S. C.; Wood, E. C.; Fu, D.; Lefer, B. L.; Flynn, J. H.; Stutz, J.

2011-12-01

Our ability to quantitatively describe urban air pollution to a large extent depends on an accurate understanding of anthropogenic emissions. In areas with a high density of individual point sources of pollution, such as petrochemical facilities with multiple flares or regions with active commercial ship traffic, this is particularly challenging as access to facilities and ships is often restricted. Direct formaldehyde emissions from flares may play an important role for ozone chemistry, acting as an initial radical precursor and enhancing the degradation of co-emitted hydrocarbons. HONO is also recognized as an important OH source throughout the day. However, very little is known about direct HCHO and HONO emissions. Imaging Differential Optical Absorption Spectroscopy (I-DOAS), a relatively new remote sensing technique, provides an opportunity to investigate emissions from these sources from a distance, making this technique attractive for fence-line monitoring. In this presentation, we will describe I-DOAS measurements during the FLAIR campaign in the spring/summer of 2009. We performed measurements outside of various industrial facilities in the larger Houston area as well as in the Houston Ship Channel to visualize and quantify the emissions of HCHO, NO2, HONO, and SO2 from flares of petrochemical facilities and ship smoke stacks. We will present the column density images of pollutant plumes as well as fluxes from individual flares calculated from I-DOAS observations. Fluxes from individual flares and smoke stacks determined from the I-DOAS measurements vary widely in time and by the emission sources. We will also present HONO/NOx ratios in ship smoke stacks derived from the combination of I-DOAS and in-situ measurements, and discuss other trace gas ratios in plumes derived from the I-DOAS observations. Finally, we will show images of HCHO, NO2 and SO2 plumes from control burn forest fires observed in November of 2009 at Vandenberg Air Force Base, Santa Maria, CA.

Compliance Testing of Eielson Air Force Base Central Heating and Power Plant, Coal Fired Boiler Number 3, Eielson Air Force Base, Alaska

DTIC Science & Technology

1988-12-01

a flue gas grab sample for orsat analysis (measures oxygen, and carbon dioxide for stack gas molecular weight determination and emissions correction... molecular weight, was obtained during particulate sampling. Testing was initially started on boiler 2 at the maximum rated steam output of 120,000 lbs/hr...I, r*~td AN[D l FL B( R\\ ViQ( lPjN L!II(,t 1 (d) Open burning of put.rcible iear- i\\ % ~i~ emisions , ec.dirig c dn jc p. c ,f1 pre- cri :rig pair

The Stacked LYα Emission Profile from the Circum-Galactic Medium of z ˜ 2 Quasars

NASA Astrophysics Data System (ADS)

Arrigoni Battaia, Fabrizio; Hennawi, Joseph F.; Cantalupo, Sebastiano; Prochaska, J. Xavier

2016-09-01

In the context of the FLASHLIGHT survey, we obtained deep narrowband images of 15 z ˜ 2 quasars with the Gemini Multi-object Spectrograph on Gemini South in an effort to measure Lyα emission from circum- and intergalactic gas on scales of hundreds of kpc from the central quasar. We do not detect bright giant Lyα nebulae (SB ˜ 10-17 erg s-1 cm-2 arcsec-2 at distances >50 kpc) around any of our sources, although we routinely (≃47%) detect smaller-scale <50 kpc Lyα emission at this surface brightness level emerging from either the extended narrow emission line regions powered by the quasars or by star formation in their host galaxies. We stack our 15 deep images to study the average extended Lyα surface brightness profile around z ˜ 2 quasars, carefully PSF-subtracting the unresolved emission component and paying close attention to sources of systematic error. Our analysis, which achieves an unprecedented depth, reveals a surface brightness of SBLyα ˜ 10-19 erg s-1 cm-2 arcsec-2 at ˜200 kpc, with a 2.3σ detection of Lyα emission at SB {}{Lyα }=(5.5+/- 3.1)× {10}-20 erg s-1 cm-2 arcsec-2 within an annulus spanning 50 kpc < R < 500 kpc from the quasars. Assuming that this Lyα emission is powered by fluorescence from highly ionized gas illuminated by the bright central quasar, we deduce an average volume density of n H = 0.6 × 10-2 cm-3 on these large scales. Our results are in broad agreement with the densities suggested by cosmological hydrodynamical simulations of massive (M ≃ 1012.5 M ⊙) quasar hosts; however, they indicate that the typical quasars at these redshifts are surrounded by gas that is a factor of ˜100 times less dense than the (˜1 cm-3) gas responsible for the giant bright Lyα nebulae around quasars recently discovered by our group. Based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), Ministério da Ciência, Tecnologia e Inovação (Brazil), and Ministerio de Ciencia, Tecnología e Innovación Productiva (Argentina).

Electrochemical cell stack assembly

DOEpatents

Jacobson, Craig P.; Visco, Steven J.; De Jonghe, Lutgard C.

2010-06-22

Multiple stacks of tubular electrochemical cells having a dense electrolyte disposed between an anode and a cathode preferably deposited as thin films arranged in parallel on stamped conductive interconnect sheets or ferrules. The stack allows one or more electrochemical cell to malfunction without disabling the entire stack. Stack efficiency is enhanced through simplified gas manifolding, gas recycling, reduced operating temperature and improved heat distribution.

Study of medical isotope production facility stack emissions and noble gas isotopic signature using automatic gamma-spectra analysis platform

NASA Astrophysics Data System (ADS)

Zhang, Weihua; Hoffmann, Emmy; Ungar, Kurt; Dolinar, George; Miley, Harry; Mekarski, Pawel; Schrom, Brian; Hoffman, Ian; Lawrie, Ryan; Loosz, Tom

2013-04-01

The nuclear industry emissions of the four CTBT (Comprehensive Nuclear-Test-Ban Treaty) relevant radioxenon isotopes are unavoidably detected by the IMS along with possible treaty violations. Another civil source of radioxenon emissions which contributes to the global background is radiopharmaceutical production companies. To better understand the source terms of these background emissions, a joint project between HC, ANSTO, PNNL and CRL was formed to install real-time detection systems to support 135Xe, 133Xe, 131mXe and 133mXe measurements at the ANSTO and CRL 99Mo production facility stacks as well as the CANDU (CANada Deuterium Uranium) primary coolant monitoring system at CRL. At each site, high resolution gamma spectra were collected every 15 minutes using a HPGe detector to continuously monitor a bypass feed from the stack or CANDU primary coolant system as it passed through a sampling cell. HC also conducted atmospheric monitoring for radioxenon at approximately 200 km distant from CRL. A program was written to transfer each spectrum into a text file format suitable for the automatic gamma-spectra analysis platform and then email the file to a server. Once the email was received by the server, it was automatically analysed with the gamma-spectrum software UniSampo/Shaman to perform radionuclide identification and activity calculation for a large number of gamma-spectra in a short period of time (less than 10 seconds per spectrum). The results of nuclide activity together with other spectrum parameters were saved into the Linssi database. This database contains a large amount of radionuclide information which is a valuable resource for the analysis of radionuclide distribution within the noble gas fission product emissions. The results could be useful to identify the specific mechanisms of the activity release. The isotopic signatures of the various radioxenon species can be determined as a function of release time. Comparison of 133mXe and 133Xe activity ratios showed distinct differences between the closed CANDU primary coolant system and radiopharmaceutical production releases. According to the concept proposed by Kalinowski and Pistner (2006), the relationship between different isotopic activity ratios based on three or four radioxenon isotopes was plotted in a log-log diagram for source characterisation (civil vs. nuclear test). The multiple isotopic activity ratios were distributed in three distinct areas: HC atmospheric monitoring ratios extended to far left; the CANDU primary coolant system ratios lay in the middle; and 99Mo stack monitoring ratios for ANSTO and CRL were located on the right. The closed CANDU primary coolant has the lowest logarithmic mean ratio that represents the nuclear power reactor operation. The HC atmospheric monitoring exhibited a broad range of ratios spreading over several orders of magnitude. In contrast, the ANSTO and CRL stack emissions showed the smallest range of ratios but the results indicate at least two processes involved in the 99Mo productions. Overall, most measurements were found to be shifted towards the reactor domain. The hypothesis is that this is due to an accumulation of the isotope 131mXe in the stack or atmospheric background as it has the longest half-life and extra 131mXe emissions from the decay of 131I. The contribution of older 131mXe to a fresh release shifts the ratio of 133mXe/131mXe to the left. It was also very interesting to note that there were some situations where isotopic ratios from 99Mo production emissions fell within the nuclear test domain. This is due to operational variability, such as shorter target irradiation times. Martin B. Kalinowski and Christoph Pistner, (2006), Isotopic signature of atmospheric xenon released from light water reactors, Journal of Environmental Radioactivity, 88, 215-235.

Airborne DOAS retrievals of methane, carbon dioxide, and water vapor concentrations at high spatial resolution: application to AVIRIS-NG

NASA Astrophysics Data System (ADS)

Thorpe, Andrew K.; Frankenberg, Christian; Thompson, David R.; Duren, Riley M.; Aubrey, Andrew D.; Bue, Brian D.; Green, Robert O.; Gerilowski, Konstantin; Krings, Thomas; Borchardt, Jakob; Kort, Eric A.; Sweeney, Colm; Conley, Stephen; Roberts, Dar A.; Dennison, Philip E.

2017-10-01

At local scales, emissions of methane and carbon dioxide are highly uncertain. Localized sources of both trace gases can create strong local gradients in its columnar abundance, which can be discerned using absorption spectroscopy at high spatial resolution. In a previous study, more than 250 methane plumes were observed in the San Juan Basin near Four Corners during April 2015 using the next-generation Airborne Visible/Infrared Imaging Spectrometer (AVIRIS-NG) and a linearized matched filter. For the first time, we apply the iterative maximum a posteriori differential optical absorption spectroscopy (IMAP-DOAS) method to AVIRIS-NG data and generate gas concentration maps for methane, carbon dioxide, and water vapor plumes. This demonstrates a comprehensive greenhouse gas monitoring capability that targets methane and carbon dioxide, the two dominant anthropogenic climate-forcing agents. Water vapor results indicate the ability of these retrievals to distinguish between methane and water vapor despite spectral interference in the shortwave infrared. We focus on selected cases from anthropogenic and natural sources, including emissions from mine ventilation shafts, a gas processing plant, tank, pipeline leak, and natural seep. In addition, carbon dioxide emissions were mapped from the flue-gas stacks of two coal-fired power plants and a water vapor plume was observed from the combined sources of cooling towers and cooling ponds. Observed plumes were consistent with known and suspected emission sources verified by the true color AVIRIS-NG scenes and higher-resolution Google Earth imagery. Real-time detection and geolocation of methane plumes by AVIRIS-NG provided unambiguous identification of individual emission source locations and communication to a ground team for rapid follow-up. This permitted verification of a number of methane emission sources using a thermal camera, including a tank and buried natural gas pipeline.

Effects of Co-Processing Sewage Sludge in the Cement Kiln on PAHs, Heavy Metals Emissions and the Surrounding Environment.

PubMed

Lv, Dong; Zhu, Tianle; Liu, Runwei; Li, Xinghua; Zhao, Yuan; Sun, Ye; Wang, Hongmei; Zhang, Fan; Zhao, Qinglin

2018-04-08

To understand the effects of co-processing sewage sludge in the cement kiln on non-criterion pollutants emissions and its surrounding environment, the flue gas from a cement kiln stack, ambient air and soil from the background/downwind sites were collected in the cement plant. Polycyclic aromatic hydrocarbons (PAHs) and heavy metals of the samples were analyzed. The results show that PAHs in flue gas mainly exist in the gas phase and the low molecular weight PAHs are the predominant congener. The co-processing sewage sludge results in the increase in PAHs and heavy metals emissions, especially high molecular weight PAHs and low-volatile heavy metals such as Cd and Pb in the particle phase, while it does not change their compositions and distribution patterns significantly. The concentrations and their distributions of the PAHs and heavy metals between the emissions and ambient air have a positive correlation and the co-processing sewage sludge results in the increase of PAHs and heavy metals concentrations in the ambient air. The PAHs concentration level and their distribution in soil are proportional to those in the particle phase of flue gas, and the co-processing sewage sludge can accelerate the accumulation of the PAHs and heavy metals in the surrounding soil, especially high/middle molecular weight PAHs and low-volatile heavy metals.

Gas flaring and resultant air pollution: A review focusing on black carbon.

PubMed

Fawole, Olusegun G; Cai, X-M; MacKenzie, A R

2016-09-01

Gas flaring is a prominent source of VOCs, CO, CO2, SO2, PAH, NOX and soot (black carbon), all of which are important pollutants which interact, directly and indirectly, in the Earth's climatic processes. Globally, over 130 billion cubic metres of gas are flared annually. We review the contribution of gas flaring to air pollution on local, regional and global scales, with special emphasis on black carbon (BC, "soot"). The temporal and spatial characteristics of gas flaring distinguishes it from mobile combustion sources (transport), while the open-flame nature of gas flaring distinguishes it from industrial point-sources; the high temperature, flame control, and spatial compactness distinguishes gas flaring from both biomass burning and domestic fuel-use. All of these distinguishing factors influence the quantity and characteristics of BC production from gas flaring, so that it is important to consider this source separately in emissions inventories and environmental field studies. Estimate of the yield of pollutants from gas flaring have, to date, paid little or no attention to the emission of BC with the assumption often being made that flaring produces a smokeless flame. In gas flares, soot yield is known to depend on a number of factors, and there is a need to develop emission estimates and modelling frameworks that take these factors into consideration. Hence, emission inventories, especially of the soot yield from gas flaring should give adequate consideration to the variation of fuel gas composition, and to combustion characteristics, which are strong determinants of the nature and quantity of pollutants emitted. The buoyant nature of gas flaring plume, often at temperatures in the range of 2000 K, coupled with the height of the stack enables some of the pollutants to escape further into the free troposphere aiding their long-range transport, which is often not well-captured by model studies. Copyright © 2016 Elsevier Ltd. All rights reserved.

40 CFR 75.82 - Monitoring of Hg mass emissions and heat input at common and multiple stacks.

Code of Federal Regulations, 2010 CFR

2010-07-01

... heat input at common and multiple stacks. 75.82 Section 75.82 Protection of Environment ENVIRONMENTAL... Provisions § 75.82 Monitoring of Hg mass emissions and heat input at common and multiple stacks. (a) Unit... systems and perform the Hg emission testing described under § 75.81(b). If reporting of the unit heat...

Estimation and characterization of polycyclic aromatic hydrocarbons from magnesium metallurgy facilities in China.

PubMed

Nie, Zhiqiang; Yang, Yufei; Tang, Zhenwu; Liu, Feng; Wang, Qi; Huang, Qifei

2014-11-01

Field monitoring was conducted to develop a polycyclic aromatic hydrocarbon (PAH) emission inventory for the magnesium (Mg) metallurgy industry in China. PAH emissions in stack gas and fly/bottom ash samples from different smelting units of a typical Mg smelter were measured and compared. Large variations of concentrations, congener patterns, and emission factors of PAHs during the oxidation and reduction stages in the Mg smelter were observed. The measured average emission factor (166,487 μg/t Mg) was significantly higher than those of other industrial sources. Annual emission from Mg metallurgy in 2012 in China was estimated at 116 kg (514 g BaPeq) for PAHs. The results of this study suggest that PAH emission from Mg industries should be considered by local government agencies. These data may be helpful for understanding PAH levels produced by the Mg industry and in developing a PAH inventory.

Morphology Dependence of Stellar Age in Quenched Galaxies at Redshift ˜1.2: Massive Compact Galaxies Are Older than More Extended Ones

NASA Astrophysics Data System (ADS)

Williams, Christina C.; Giavalisco, Mauro; Bezanson, Rachel; Cappelluti, Nico; Cassata, Paolo; Liu, Teng; Lee, Bomee; Tundo, Elena; Vanzella, Eros

2017-04-01

We report the detection of morphology-dependent stellar age in massive quenched galaxies (QGs) at z ˜ 1.2. The sense of the dependence is that compact QGs are 0.5-2 Gyr older than normal-sized ones. The evidence comes from three different age indicators—{D}n4000, {{{H}}}δ , and fits to spectral synthesis models—applied to their stacked optical spectra. All age indicators consistently show that the stellar populations of compact QGs are older than those of their normal-sized counterparts. We detect weak [O II] emission in a fraction of QGs, and the strength of the line, when present, is similar between the two samples; however, compact galaxies exhibit a significantly lower frequency of [O II] emission than normal ones. Fractions of both samples are individually detected in 7 Ms Chandra X-ray images (luminosities ˜1040-1041 erg s-1). The 7 Ms stacks of nondetected galaxies show similarly low luminosities in the soft band only, consistent with a hot gas origin for the X-ray emission. While both [O II] emitters and nonemitters are also X-ray sources among normal galaxies, no compact galaxy with [O II] emission is an X-ray source, arguing against an active galactic nucleus (AGN) powering the line in compact galaxies. We interpret the [O II] properties as further evidence that compact galaxies are older and further along in the process of quenching star formation and suppressing gas accretion. Finally, we argue that the older age of compact QGs is evidence of progenitor bias: compact QGs simply reflect the smaller sizes of galaxies at their earlier quenching epoch, with stellar density most likely having nothing directly to do with cessation of star formation.

Applications of optical measurement technology in pollution gas monitoring at thermal power plants

NASA Astrophysics Data System (ADS)

Wang, Jian; Yu, Dahai; Ye, Huajun; Yang, Jianhu; Ke, Liang; Han, Shuanglai; Gu, Haitao; Chen, Yingbin

2011-11-01

This paper presents the work of using advanced optical measurement techniques to implement stack gas emission monitoring and process control. A system is designed to conduct online measurement of SO2/NOX and mercury emission from stacks and slipping NH3 of de-nitrification process. The system is consisted of SO2/NOX monitoring subsystem, mercury monitoring subsystem, and NH3 monitoring subsystem. The SO2/NOX monitoring subsystem is developed based on the ultraviolet differential optical absorption spectroscopy (UV-DOAS) technique. By using this technique, a linearity error less than +/-1% F.S. is achieved, and the measurement errors resulting from optical path contamination and light fluctuation are removed. Moreover, this subsystem employs in situ extraction and hot-wet line sampling technique to significantly reduce SO2 loss due to condensation and protect gas pipeline from corrosion. The mercury monitoring subsystem is used to measure the concentration of element mercury (Hg0), oxidized mercury (Hg2+), and total gaseous mercury (HgT) in the flue gas exhaust. The measurement of Hg with a low detection limit (0.1μg/m3) and a high sensitivity is realized by using cold vapor atom fluorescence spectroscopy (CVAFS) technique. This subsystem is also equipped with an inertial separation type sampling technique to prevent gas pipeline from being clogged and to reduce speciation mercury measurement error. The NH3 monitoring subsystem is developed to measure the concentration of slipping NH3 and then to help improving the efficiency of de-nitrification. The NH3 concentration as low as 0.1ppm is able to be measured by using the off-axis integrated cavity output spectroscopy (ICOS) and the tunable diode laser absorption spectroscopy (TDLAS) techniques. The problem of trace NH3 sampling loss is solved by applying heating the gas pipelines when the measurement is running.

Evaluation of distributed gas cooling of pressurized PAFC for utility power generation

NASA Technical Reports Server (NTRS)

Farooque, M.; Hooper, M.; Maru, H.

1981-01-01

A proof-of-concept test for a gas-cooled pressurized phosphoric acid fuel cell is described. After initial feasibility studies in short stacks, two 10 kW stacks are tested. Progress includes: (1) completion of design of the test stations with a recirculating gas cooling loop; (2) atmospheric testing of the baseline stack.

Modular fuel-cell stack assembly

DOEpatents

Patel, Pinakin

2010-07-13

A fuel cell assembly having a plurality of fuel cells arranged in a stack. An end plate assembly abuts the fuel cell at an end of said stack. The end plate assembly has an inlet area adapted to receive an exhaust gas from the stack, an outlet area and a passage connecting the inlet area and outlet area and adapted to carry the exhaust gas received at the inlet area from the inlet area to the outlet area. A further end plate assembly abuts the fuel cell at a further opposing end of the stack. The further end plate assembly has a further inlet area adapted to receive a further exhaust gas from the stack, a further outlet area and a further passage connecting the further inlet area and further outlet area and adapted to carry the further exhaust gas received at the further inlet area from the further inlet area to the further outlet area.

Assessment of the Revised 3410 Building Filtered Exhaust Stack Sampling Probe Location

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yu, Xiao-Ying; Recknagle, Kurtis P.; Glissmeyer, John A.

2013-12-01

In order to support the air emissions permit for the 3410 Building, Pacific Northwest National Laboratory performed a series of tests in the exhaust air discharge from the reconfigured 3410 Building Filtered Exhaust Stack. The objective was to determine whether the location of the air sampling probe for emissions monitoring meets the applicable regulatory criteria governing such effluent monitoring systems. In particular, the capability of the air sampling probe location to meet the acceptance criteria of ANSI/HPS N13.1-2011 , Sampling and Monitoring Releases of Airborne Radioactive Substances from the Stack and Ducts of Nuclear Facilities was determined. The qualification criteriamore » for these types of stacks address 1) uniformity of air velocity, 2) sufficiently small flow angle with respect to the axis of the duct, 3) uniformity of tracer gas concentration, and 4) uniformity of tracer particle concentration. Testing was performed to conform to the quality requirements of NQA-1-2000. Fan configurations tested included all fan combinations of any two fans at a time. Most of the tests were conducted at the normal flow rate, while a small subset of tests was performed at a slightly higher flow rate achieved with the laboratory hood sashes fully open. The qualification criteria for an air monitoring probe location are taken from ANSI/HPS N13.1-2011 and are paraphrased as follows with key results summarized: 1. Angular Flow—The average air velocity angle must not deviate from the axis of the stack or duct by more than 20°. Our test results show that the mean angular flow angles at the center two-thirds of the ducts are smaller than 4.5% for all testing conditions. 2. Uniform Air Velocity—The acceptance criterion is that the COV of the air velocity must be ≤ 20% across the center two thirds of the area of the stack. Our results show that the COVs of the air velocity across the center two-thirds of the stack are smaller than 2.9% for all testing conditions. 3. Uniform Concentration of Tracer Gases—The uniformity of the concentration of potential contaminants is first tested using a tracer gas to represent gaseous effluents. The tracer is injected downstream of the fan outlets and at the junction downstream fan discharges meet. The acceptance criteria are that 1) the COV of the measured tracer gas concentration is ≤20% across the center two-thirds of the sampling plane and 2) at no point in the sampling plane does the concentration vary from the mean by >30%. Our test results show that 1) the COV of the measured tracer gas concentration is < 2.9% for all test conditions and 2) at no point in the sampling plane does the concentration vary from the mean by >6.5%. 4. Uniform Concentration of Tracer Particles—Tracer particles of 10-μm aerodynamic diameter are used for the second demonstration of concentration uniformity. The acceptance criterion is that the COV of particle concentration is ≤ 20% across the center two thirds of the sampling plane. Our test results indicate that the COV of particle concentration is <9.9% across the center two-thirds of the sampling plane among all testing conditions. Thus, the reconfigured 3410 Building Filtered Exhaust Stack was determined to meet the qualification criteria given in the ANSI/HPS N13.1-2011 standard. Changes to the system configuration or operations outside the bounds described in this report (e.g., exhaust stack velocity changes, relocation of sampling probe, and addition of fans) may require re-testing or re-evaluation to determine compliance.« less

Neutral hydrogen gas, past and future star formation in galaxies in and around the ‘Sausage’ merging galaxy cluster

DOE PAGES

Stroe, Andra; Oosterloo, Tom; Rottgering, Huub J. A.; ...

2015-07-25

CIZA J2242.8+5301 (z = 0.188, nicknamed ‘Sausage’) is an extremely massive (M 200 ~2.0 × 10 15 M ⊙), merging cluster with shock waves towards its outskirts, which was found to host numerous emission line galaxies. We performed extremely deep Westerbork Synthesis Radio Telescope H i observations of the ‘Sausage’ cluster to investigate the effect of the merger and the shocks on the gas reservoirs fuelling present and future star formation (SF) in cluster members. By using spectral stacking, we find that the emission line galaxies in the ‘Sausage’ cluster have, on average, as much H i gas as fieldmore » galaxies (when accounting for the fact cluster galaxies are more massive than the field galaxies), contrary to previous studies. Since the cluster galaxies are more massive than the field spirals, they may have been able to retain their gas during the cluster merger. The large H i reservoirs are expected to be consumed within ~0.75–1.0 Gyr by the vigorous SF and active galactic nuclei activity and/or driven out by the outflows we observe. We find that the star formation rate (SFR) in a large fraction of H α emission line cluster galaxies correlates well with the radio broad-band emission, tracing supernova remnant emission. This suggests that the cluster galaxies, all located in post-shock regions, may have been undergoing sustained SFR for at least 100 Myr. In conclusion, this fully supports the interpretation proposed by Stroe et al. and Sobral et al. that gas-rich cluster galaxies have been triggered to form stars by the passage of the shock.« less

Factors governing particle number emissions in a waste-to-energy plant.

PubMed

Ozgen, Senem; Cernuschi, Stefano; Giugliano, Michele

2015-05-01

Particle number concentration and size distribution measurements were performed on the stack gas of a waste-to-energy plant which co-incinerates municipal solid waste, sewage sludge and clinical waste in two lines. Average total number of particles was found to be 4.0·10(5)cm(-3) and 1.9·10(5)cm(-3) for the line equipped with a wet flue gas cleaning process and a dry cleaning system, respectively. Ultrafine particles (dp<100nm) accounted for about 97% of total number concentration for both lines, whereas the nanoparticle (dp<50nm) contribution differed slightly between the lines (87% and 84%). The experimental data is explored statistically through some multivariate pattern identifying methods such as factor analysis and cluster analysis to help the interpretation of the results regarding the origin of the particles in the flue gas with the objective of determining the factors governing the particle number emissions. The higher moisture of the flue gas in the wet cleaning process was found to increase the particle number emissions on average by a factor of about 2 due to increased secondary formation of nanoparticles through nucleation of gaseous precursors such as sulfuric acid, ammonia and water. The influence of flue gas dilution and cooling monitored through the variation of the sampling conditions also confirms the potential effect of the secondary new particle formation in increasing the particle number emissions. This finding shows the importance of reporting the experimental conditions in detail to enable the comparison and interpretation of particle number emissions. Regarding the fuel characteristics no difference was observed in terms of particle number concentration and size distributions between the clinical waste feed and the municipal solid waste co-incineration with sludge. Copyright © 2015 Elsevier Ltd. All rights reserved.

Theoretical Evidence for the Stronger Ability of Thymine to Disperse SWCNT than Cytosine and Adenine: self-stacking of DNA bases vs their cross-stacking with SWCNT

PubMed Central

Wang, Yixuan

2008-01-01

Self-stacking of four DNA bases, adenine (A), cytosine (C), guanine (G) and thymine (T), and their cross-stacking with (5,5) as well as (10,0) single walled carbon nanotubes (SWCNTs) were extensively investigated with a novel hybrid DFT method, MPWB1K/cc-pVDZ. The binding energies were further corrected with MP2/6-311++G(d,p) method in both gas phase and aqueous solution, where the solvent effects were included with conductor-like polarized continuum model (CPCM) model and UAHF radii. The strongest self-stacking of G and A takes displaced anti-parallel configuration, but un-displaced or “eclipsed” anti-parallel configuration is the most stable for C and T. In gas phase the self-stacking of nucleobases decreases in the sequence G>A>C>T, while because of quite different solvent effects their self-stacking in aqueous solution exhibits a distinct sequence A>G>T>C. For a given base, cross-stacking is stronger than self-stacking in both gas phase and aqueous solution. Binding energy for cross-stacking in gas phase varies as G>A>T>C for both (10,0) and (5,5) SWCNTs, and the binding of four nucleobases to (10,0) is slightly stronger than to (5,5) SWCNT by a range of 0.1–0.5 kcal/mol. The cross-stacking in aqueous solution varies differently from that gas phase: A>G>T>C for (10,0) SWCNT and G>A>T>C for (5,5) SWCNT. It is suggested that the ability of nucleobases to disperse SWCNT depends on relative strength (ΔΔEbinsol) of self-stacking and cross-stacking with SWCNT in aqueous solution. Of the four investigated nucleobases thymine (T) exhibits the highest (ΔΔEbinsol) which can well explain the experimental finding that T more efficiently functionalizes SWCNT than C and A. PMID:18946514

Compliance Testing of Grissom AFB Central Heating Plant Coal-Fired Boilers 3 and 5, Grissom AFB, Indiana

DTIC Science & Technology

1988-06-01

common breeching and can be routed to the wet-scrubber or to a bypass stack. The scrubber is a double-alkali flue - gas desulfurization system using soda...Illustrations Figure Title Page 1 View of Scrubber and Bypass Stacks 3 2 Scrubber Stacks 4 3 Bypass Stack 5 4 Flue Gas Flow Diagram 6 5 ORSAT Sampling...of gases and to provide a positive static pressure at flue gas exhaust discharge points. The ash system pneumatically removes ash from bottom-ash

[Atmospheric emission of PCDD/Fs from secondary aluminum metallurgy industry in the southwest area, China].

PubMed

Lu, Yi; Zhang, Xiao-Ling; Guo, Zhi-Shun; Jian, Chuan; Zhu, Ming-Ji; Deng, Li; Sun, Jing; Zhang, Qin

2014-01-01

Five secondary aluminum metallurgy enterprises in the southwest area of China were measured for emissions of PCDD/Fs. The results indicated that the emission levels of PCDD/Fs (as TEQ) were 0.015-0.16 ng x m(-3), and the average was 0.093 ng x m(-3) from secondary aluminum metallurgy enterprises. Emission factors of PCDD/Fs (as TEQ) from the five secondary aluminum metallurgy enterprises varied between 0.041 and 4.68 microg x t(-1) aluminum, and the average was 2.01 microg x t(-1) aluminum; among them, PCDD/Fs emission factors from the crucible smelting furnace was the highest. Congener distribution of PCDD/F in stack gas from the five secondary aluminum metallurgies was very different from each other. Moreover, the R(PCDF/PCDD) was the lowest in the enterprise which was installed only with bag filters; the R(PCDF/PCDD) were 3.8-12.6 (the average, 7.7) in the others which were installed with water scrubbers. The results above indicated that the mechanism of PCDD/Fs formation was related to the types of exhaust gas treatment device. The results of this study can provide technical support for the formulation of PCDD/Fs emission standards and the best available techniques in the secondary aluminum metallurgy industry.

Dilution-based emissions sampling from stationary sources: Part 2--Gas-fired combustors compared with other fuel-fired systems.

PubMed

England, Glenn C; Watson, John G; Chow, Judith C; Zielinska, Barbara; Chang, M C Oliver; Loos, Karl R; Hidy, George M

2007-01-01

With the recent focus on fine particle matter (PM2.5), new, self-consistent data are needed to characterize emissions from combustion sources. Such data are necessary for health assessment and air quality modeling. To address this need, emissions data for gas-fired combustors are presented here, using dilution sampling as the reference. The dilution method allows for collection of emitted particles under conditions simulating cooling and dilution during entry from the stack into the air. The sampling and analysis of the collected particles in the presence of precursor gases, SO2 nitrogen oxide, volatile organic compound, and NH3 is discussed; the results include data from eight gas fired units, including a dual-fuel institutional boiler and a diesel engine powered electricity generator. These data are compared with results in the literature for heavy-duty diesel vehicles and stationary sources using coal or wood as fuels. The results show that the gas-fired combustors have very low PM2.5 mass emission rates in the range of approximately 10(-4) lb/million Btu (MMBTU) compared with the diesel backup generator with particle filter, with approximately 5 x 10(-3) lb/MMBTU. Even higher mass emission rates are found in coal-fired systems, with rates of approximately 0.07 lb/MMBTU for a bag-filter-controlled pilot unit burning eastern bituminous coal. The characterization of PM2.5 chemical composition from the gas-fired units indicates that much of the measured primary particle mass in PM2.5 samples is organic or elemental carbon and, to a much less extent, sulfate. Metal emissions are quite low compared with the diesel engines and the coal- or wood-fueled combustors. The metals found in the gas-fired combustor particles are low in concentration, similar in concentration to ambient particles. The interpretation of the particulate carbon emissions is complicated by the fact that an approximately equal amount of particulate carbon (mainly organic carbon) is found on the particle collector and a backup filter. It is likely that measurement artifacts, mostly adsorption of volatile organic compounds on quartz filters, are positively biasing "true" particulate carbon emission results.

L'Anse Warden Electric Company Boiler Number One Emission Test Report – March 2017

EPA Pesticide Factsheets

L’Anse Warden Electric Company (LWEC) submitted results from an emission test on the Boiler No. 1 stack. Stack air emission testing was conducted in March 2017, and the report became available in June 2017

L'Anse Warden Electric Company Boiler Number One Emission Test Report – December 2016

EPA Pesticide Factsheets

L’Anse Warden Electric Company (LWEC) submitted results from an emission test on the Boiler No. 1 stack. Stack air emission testing was conducted in December 2016, and the report became available in January 2017

L'Anse Warden Electric Company Boiler Number One Emission Test Report – July 2016

EPA Pesticide Factsheets

L’Anse Warden Electric Company (LWEC) submitted results from an emission test on the Boiler No. 1 stack. Stack air emission testing was conducted in July 2016, and the report became available in August 2016.

L'Anse Warden Electric Company Boiler Number One Emission Test Report – June 2017

EPA Pesticide Factsheets

L’Anse Warden Electric Company (LWEC) submitted results from an emission test on the Boiler No. 1 stack. Stack air emission testing was conducted in March 2017, and the report became available in June 2017

A new approach for biological online testing of stack gas condensate from municipal waste incinerators.

PubMed

Elsner, Dorothea; Fomin, Anette

2002-01-01

A biological testing system for the monitoring of stack gas condensates of municipal waste incinerators has been developed using Euglena gracilis as a test organism. The motility, velocity and cellular form of the organisms were the endpoints, calculated by an image analysis system. All endpoints showed statistically significant changes in a short time when organisms were exposed to samples collected during combustion situations with increased pollutant concentrations. The velocity of the organisms proved to be the most appropriate endpoint. A semi-continuous system with E. gracilis for monitoring stack gas condensate is proposed, which could result in an online system for testing stack gas condensates in the future.

The impact of stack geometry and mean pressure on cold end temperature of stack in thermoacoustic refrigeration systems

NASA Astrophysics Data System (ADS)

Wantha, Channarong

2018-02-01

This paper reports on the experimental and simulation studies of the influence of stack geometries and different mean pressures on the cold end temperature of the stack in the thermoacoustic refrigeration system. The stack geometry was tested, including spiral stack, circular pore stack and pin array stack. The results of this study show that the mean pressure of the gas in the system has a significant impact on the cold end temperature of the stack. The mean pressure of the gas in the system corresponds to thermal penetration depth, which results in a better cold end temperature of the stack. The results also show that the cold end temperature of the pin array stack decreases more than that of the spiral stack and circular pore stack geometry by approximately 63% and 70%, respectively. In addition, the thermal area and viscous area of the stack are analyzed to explain the results of such temperatures of thermoacoustic stacks.

40 CFR 63.307 - Standards for bypass/bleeder stacks.

Code of Federal Regulations, 2014 CFR

2014-07-01

... National Emission Standards for Coke Oven Batteries § 63.307 Standards for bypass/bleeder stacks. (a)(1.... (2) Coke oven emissions shall not be vented to the atmosphere through bypass/bleeder stacks, except.... (3) The owner or operator of a brownfield coke oven battery or a padup rebuild shall install such a...

40 CFR 63.307 - Standards for bypass/bleeder stacks.

Code of Federal Regulations, 2013 CFR

2013-07-01

... National Emission Standards for Coke Oven Batteries § 63.307 Standards for bypass/bleeder stacks. (a)(1.... (2) Coke oven emissions shall not be vented to the atmosphere through bypass/bleeder stacks, except.... (3) The owner or operator of a brownfield coke oven battery or a padup rebuild shall install such a...

40 CFR 63.307 - Standards for bypass/bleeder stacks.

Code of Federal Regulations, 2012 CFR

2012-07-01

... National Emission Standards for Coke Oven Batteries § 63.307 Standards for bypass/bleeder stacks. (a)(1.... (2) Coke oven emissions shall not be vented to the atmosphere through bypass/bleeder stacks, except.... (3) The owner or operator of a brownfield coke oven battery or a padup rebuild shall install such a...

Respirable Crystalline Silica (RCS) emissions from industrial plants - Results from measurement programmes in Germany

NASA Astrophysics Data System (ADS)

Ehrlich, C.; Noll, G.; Wusterhausen, E.; Kalkoff, W.-D.; Remus, R.; Lehmann, C.

2013-04-01

Numerous research articles dealing with Respirable Crystalline Silica (RCS) in occupational health because epidemiological studies reveal an association between RCS-dust and the development of silicosis as well as an increased probability of developing lung cancer. Research activities about RCS in ambient air are known from US-measurements. However there is a lack of knowledge regarding RCS-emissions in several industrial sectors. Industrial sources of crystalline silica include construction, foundries, glass manufacturing, abrasive blasting or any industrial or commercial use of silica sand, and mining and rock crushing operations. This paper describes a RCS-emission measurement method for stack gases and report results from the German RCS-emission measurement programmes which were used to identify installations and types of industries with the highest concentration levels of RCS in stack gases. A two-stage cascade impactor was used for the measurements which separate particles into the following size fractions: >10 μm, 10-4 μm und <4 μm of aerodynamic diameter. The measurements were carried out according to international sampling standards. The size of crystalline silica particles of most concern are those respirable particles that are smaller than four microns (millionths of a metre), also called particulate matter 4 (PM4). The analytical procedure of determining crystalline silica in emission samples (in the fraction below 4 μm) consists of using x-ray diffraction and infrared spectroscopy methods which are the same methods as used in the field of occupational health. A total of 37 emission measurement campaigns were assessed (112 RCS-samples in nine industrial sectors). The investigated plants are located in different German states such as Bavaria, North Rhine Westphalia, Baden-Wuerttemberg, Rhineland-Palatinate and Saxony-Anhalt. The results of the measurements show that most of the investigated plants can achieve compliance with the newly developed German emission limit value (ELV) of 1 mg m-3. The ELV is expressed as the concentration of RCS in stack emissions. According to the German emission minimising principle and the precautionary principle it is assumed that by complying with the RCS-ELV there is no ambient air health risk for people living these plants. In the case of increased total dust concentration in the stack gas (more than 20 mg m-3) combined with increased percentage of crystalline silica in PM4 dust, a violation of the above mentioned ELV is more likely. This applies mostly to installations in the silica sand processing industry. To comply with the ELV of 1 mg m-3, efficient emission control technology should be implemented and should be well maintained.

Evaluation of gas cooling for pressurized phosphoric acid fuel cell stacks

NASA Technical Reports Server (NTRS)

Farooque, M.; Skok, A. J.; Maru, H. C.; Kothmann, R. E.; Harry, R. W.

1983-01-01

Gas cooling is a more reliable, less expensive and a more simple alternative to conventional liquid cooling for heat removal from the phosphoric acid fuel cell (PAFC). The feasibility of gas cooling has already been demonstrated in atmospheric pressure stacks. This paper presents theoretical and experimental investigation of gas cooling for pressurized PAFC. Two approaches to gas cooling, Distributed Gas Cooling (DIGAS) and Separated Gas Cooling (SGC) were considered, and a theoretical comparison on the basis of cell performance indicated SGC to be superior to DIGAS. The feasibility of SGC was experimentally demonstrated by operating a 45-cell stack for 700 hours at pressure, and determining thermal response and the effect of other related parameters.

Woodstove smoke and CO emissions: comparison of reference methods with the VIP sampler.

PubMed

Jaasma, D R; Champion, M C; Shelton, J W

1990-06-01

A new field sampler has been developed for measuring the particulate matter (PM) and carbon monoxide emissions of woodburning stoves. Particulate matter is determined by carbon balance and the workup of a sample train which is similar to a room-temperature EPA Method 5G train. A steel tank, initially evacuated, serves as the motive force for sampling and also accumulates a gas sample for post-test analysis of time-averaged stack CO and CO2 concentrations. Workup procedures can be completed within 72 hours of sampler retrieval. The system has been compared to reference methods in two laboratory test series involving six different woodburning appliances and two independent laboratories. The correlation of field sampler emission rates and reference method rates is strong.

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.

Woodstove smoke and CO emissions: Comparison of reference methods with the VIP sampler

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jaasma, D.R.; Champion, M.C.; Shelton, J.W.

1990-06-01

A new field sampler has been developed for measuring the particulate matter (PM) and carbon monoxide emissions of woodburning stoves. Particulate matter is determined by carbon balance and the workup of a sample train which is similar to a room-temperature EPA Method 5G train. A steel tank, initially evacuated, serves as the motive force for sampling and also accumulates a gas sample for post-test analysis of time-averaged stack CO and CO{sub 2} concentrations. Workup procedures can be completed within 72 hours of sampler retrieval. The system has been compared to reference methods in two laboratory test series involving six differentmore » woodburning appliances and two independent laboratories. The correlation of field sampler emission rates and reference method rates is strong.« less

Aerodynamic improvement of the assembly through which gas conduits are taken into a smoke stack by simulating gas flow on a computer

NASA Astrophysics Data System (ADS)

Prokhorov, V. B.; Fomenko, M. V.; Grigor'ev, I. V.

2012-06-01

Results from computer simulation of gas flow motion for gas conduits taken on one and two sides into the gas-removal shaft of a smoke stack with a constant cross section carried out using the SolidWorks and FlowVision application software packages are presented.

Dense plasma focus (DPF) accelerated non radio isotopic radiological source

DOEpatents

Rusnak, Brian; Tang, Vincent

2017-01-31

A non-radio-isotopic radiological source using a dense plasma focus (DPF) to produce an intense z-pinch plasma from a gas, such as helium, and which accelerates charged particles, such as generated from the gas or injected from an external source, into a target positioned along an acceleration axis and of a type known to emit ionizing radiation when impinged by the type of accelerated charged particles. In a preferred embodiment, helium gas is used to produce a DPF-accelerated He2+ ion beam to a beryllium target, to produce neutron emission having a similar energy spectrum as a radio-isotopic AmBe neutron source. Furthermore, multiple DPFs may be stacked to provide staged acceleration of charged particles for enhancing energy, tunability, and control of the source.

Application of Radioxenon Stack Emission Data in High-Resolution Atmospheric Transport Modelling

NASA Astrophysics Data System (ADS)

Kusmierczyk-Michulec, J.; Schoeppner, M.; Kalinowski, M.; Bourgouin, P.; Kushida, N.; Barè, J.

2017-12-01

The Comprehensive Nuclear-Test-Ban Treaty Organisation (CTBTO) has developed the capability to run high-resolution atmospheric transport modelling by employing WRF and Flexpart-WRF. This new capability is applied to simulate the impact of stack emission data on simulated concentrations and how the availability of such data improves the overall accuracy of atmospheric transport modelling. The presented case study focuses on xenon-133 emissions from IRE, a medical isotope production facility in Belgium, and air concentrations detected at DEX33, a monitoring station close to Freiburg, Germany. The CTBTO is currently monitoring the atmospheric concentration of xenon-133 at 25 stations and will further expand the monitoring efforts to 40 stations worldwide. The incentive is the ability to detect xenon-133 that has been produced and released from a nuclear explosion. A successful detection can be used to prove the nuclear nature of an explosion and even support localization efforts. However, xenon-133 is also released from nuclear power plants and to a larger degree from medical isotope production facilities. The availability of stack emission data in combination with atmospheric transport modelling can greatly facilitate the understanding of xenon-133 concentrations detected at monitoring stations to distinguish between xenon-133 that has been emitted from a nuclear explosion and from civilian sources. Newly available stack emission data is used with a high-resolution version of the Flexpart atmospheric transport model, namely Flexpart-WRF, to assess the impact of the emissions on the detected concentrations and the advantage gained from the availability of such stack emission data. The results are analyzed with regard to spatial and time resolution of the high-resolution model and in comparison to conventional atmospheric transport models with and without stack emission data.

Flow Characteristics of a Multiple Nozzle Exhaust Gas Eductor System.

DTIC Science & Technology

1981-03-01

these exhaust gases are a temperatures significantly above those of conventionally powered ships. A few of the problems caused by these high temperatures ...systems designed for marine gas turbine applications must substantially cool exhaust gases , present an exterior stack surface temperature which will not...stack in. H 02 R - Gas constant for air, 53.34 ft-lbf/Ibm-R s - Entropy, Btu/Ibm-R S - Primary dimension of mixing stack T - Absolute temperature , R

Performance Testing of Tracer Gas and Tracer Aerosol Detectors for use in Radionuclide NESHAP Compliance Testing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fuehne, David Patrick; Lattin, Rebecca Renee

The Rad-NESHAP program, part of the Air Quality Compliance team of LANL’s Compliance Programs group (EPC-CP), and the Radiation Instrumentation & Calibration team, part of the Radiation Protection Services group (RP-SVS), frequently partner on issues relating to characterizing air flow streams. This memo documents the most recent example of this partnership, involving performance testing of sulfur hexafluoride detectors for use in stack gas mixing tests. Additionally, members of the Rad-NESHAP program performed a functional trending test on a pair of optical particle counters, comparing results from a non-calibrated instrument to a calibrated instrument. Prior to commissioning a new stack samplingmore » system, the ANSI Standard for stack sampling requires that the stack sample location must meet several criteria, including uniformity of tracer gas and aerosol mixing in the air stream. For these mix tests, tracer media (sulfur hexafluoride gas or liquid oil aerosol particles) are injected into the stack air stream and the resulting air concentrations are measured across the plane of the stack at the proposed sampling location. The coefficient of variation of these media concentrations must be under 20% when evaluated over the central 2/3 area of the stack or duct. The instruments which measure these air concentrations must be tested prior to the stack tests in order to ensure their linear response to varying air concentrations of either tracer gas or tracer aerosol. The instruments used in tracer gas and aerosol mix testing cannot be calibrated by the LANL Standards and Calibration Laboratory, so they would normally be sent off-site for factory calibration by the vendor. Operational requirements can prevent formal factory calibration of some instruments after they have been used in hazardous settings, e.g., within a radiological facility with potential airborne contamination. The performance tests described in this document are intended to demonstrate the reliable performance of the test instruments for the specific tests used in stack flow characterization.« less

Imaging spectrophotometry of ionized gas in NGC 1068. I - Kinematics of the narrow-line region

NASA Technical Reports Server (NTRS)

Cecil, Gerald; Bland, Jonathan; Tully, R. Brent

1990-01-01

The kinematics of collisionally excited forbidden N II 6548, 6583 across the inner 1 arcmin diameter of the nearby Seyfert galaxy NGC 1068 is mapped using an imaging Fabry-Perot interferometer and low-noise CCD. The stack of monochromatic images, which spatially resolved the high-velocity gas, was analyzed for kinematic and photometric content. Profiles agree well with previous long-slit work, and their complete spatial coverage makes it possible to constrain the gas volume distribution. It is found that the narrow-line region is distributed in a thick center-darkened, line-emitting cylinder that envelopes the collimated radio jet. Three distinct kinematic subsystems, of which the cylinder is composed, are discussed in detail. Detailed behavior of the emission-line profiles, at the few points in the NE quadrant with simple kinematics, argues that the ionized gas develops a significant component of motion perpendicular to the jet axis.

Co-flow planar SOFC fuel cell stack

DOEpatents

Chung, Brandon W.; Pham, Ai Quoc; Glass, Robert S.

2004-11-30

A co-flow planar solid oxide fuel cell stack with an integral, internal manifold and a casing/holder to separately seal the cell. This construction improves sealing and gas flow, and provides for easy manifolding of cell stacks. In addition, the stack construction has the potential for an improved durability and operation with an additional increase in cell efficiency. The co-flow arrangement can be effectively utilized in other electrochemical systems requiring gas-proof separation of gases.

Electrically insulating and sealing frame

DOEpatents

Guthrie, Robin J.

1983-11-08

A combination gas seal and electrical insulator having a closed frame shape interconnects a fuel cell stack and a reactant gas plenum of a fuel cell generator. The frame can be of rectangular shape including at least one slidable spline connection in each side to permit expansion or contraction consistent with that of the walls of the gas plenum and fuel cell stack. The slidable spline connections in the frame sides minimizes lateral movement between the frame side members and sealing material interposed between the frame and the fuel cell stack or between the frame and the reactant gas plenum.

30 CFR 250.441 - What are the requirements for a surface BOP stack?

Code of Federal Regulations, 2011 CFR

2011-07-01

... ENFORCEMENT, DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Blowout Preventer (bop) System Requirements § 250.441 What are the requirements for a surface BOP stack? (a) When you drill with a surface BOP stack, you must install the BOP...

30 CFR 250.441 - What are the requirements for a surface BOP stack?

Code of Federal Regulations, 2012 CFR

2012-07-01

..., DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Blowout Preventer (bop) System Requirements § 250.441 What are the requirements for a surface BOP stack? (a) When you drill with a surface BOP stack, you must install the BOP...

30 CFR 250.441 - What are the requirements for a surface BOP stack?

Code of Federal Regulations, 2014 CFR

2014-07-01

..., DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Blowout Preventer (bop) System Requirements § 250.441 What are the requirements for a surface BOP stack? (a) When you drill with a surface BOP stack, you must install the BOP...

30 CFR 250.441 - What are the requirements for a surface BOP stack?

Code of Federal Regulations, 2013 CFR

2013-07-01

..., DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Blowout Preventer (bop) System Requirements § 250.441 What are the requirements for a surface BOP stack? (a) When you drill with a surface BOP stack, you must install the BOP...

Porous coolant tube holder for fuel cell stack

DOEpatents

Guthrie, Robin J.

1981-01-01

A coolant tube holder for a stack of fuel cells is a gas porous sheet of fibrous material adapted to be sandwiched between a cell electrode and a nonporous, gas impervious flat plate which separates adjacent cells. The porous holder has channels in one surface with coolant tubes disposed therein for carrying coolant through the stack. The gas impervious plate is preferably bonded to the opposite surface of the holder, and the channel depth is the full thickness of the holder.

Performance model of a recirculating stack nickel hydrogen cell

NASA Technical Reports Server (NTRS)

Zimmerman, Albert H.

1994-01-01

A theoretical model of the nickel hydrogen battery cell has been utilized to describe the chemical and physical changes during charge and overcharge in a recirculating stack nickel hydrogen cell. In particular, the movement of gas and electrolyte have been examined as a function of the amount of electrolyte put into the cell stack during cell activation, and as a function of flooding in regions of the gas screen in this cell design. Additionally, a two-dimensional variation on this model has been utilized to describe the effects of non-uniform loading in the nickel-electrode on the movement of gas and electrolyte within the recirculating stack nickel hydrogen cell. The type of nonuniform loading that has been examined here is that associated with higher than average loading near the surface of the sintered nickel electrode, a condition present to some degree in many nickel electrodes made by electrochemical impregnation methods. The effects of high surface loading were examined primarily under conditions of overcharge, since the movement of gas and electrolyte in the overcharging condition was typically where the greatest effects of non-uniform loading were found. The results indicate that significant changes in the capillary forces between cell components occur as the percentage of free volume in the stack filled by electrolyte becomes very high. These changes create large gradients in gas-filled space and oxygen concentrations near the boundary between the separator and the hydrogen electrode when the electrolyte fill is much greater than about 95 percent of the stack free volume. At lower electrolyte fill levels, these gaseous and electrolyte gradients become less extreme, and shift through the separator towards the nickel electrode. Similarly, flooding of areas in the gas screen cause higher concentrations of oxygen gas to approach the platinum/hydrogen electrode that is opposite the back side of the nickel electrode. These results illustrate the need for appropriate pore size distributions, and the maintenance of both convective electrolyte and gas flow paths through the stack, if the recirculating stack nickel hydrogen cell design is to work properly.

Hopewell Beneficial CO2 Capture for Production of Fuels, Fertilizer and Energy

DOE Office of Scientific and Technical Information (OSTI.GOV)

UOP; Honeywell Resins & Chemicals; Honeywell Process Solutions

2010-09-30

For Phase 1 of this project, the Hopewell team developed a detailed design for the Small Scale Pilot-Scale Algal CO2 Sequestration System. This pilot consisted of six (6) x 135 gallon cultivation tanks including systems for CO2 delivery and control, algal cultivation, and algal harvesting. A feed tank supplied Hopewell wastewater to the tanks and a receiver tank collected the effluent from the algal cultivation system. The effect of environmental parameters and nutrient loading on CO2 uptake and sequestration into biomass were determined. Additionally the cost of capturing CO2 from an industrial stack emission at both pilot and full-scale wasmore » determined. The engineering estimate evaluated Amine Guard technology for capture of pure CO2 and direct stack gas capture and compression. The study concluded that Amine Guard technology has lower lifecycle cost at commercial scale, although the cost of direct stack gas capture is lower at the pilot scale. Experiments conducted under high concentrations of dissolved CO2 did not demonstrate enhanced algae growth rate. This result suggests that the dissolved CO2 concentration at neutral pH was already above the limiting value. Even though dissolved CO2 did not show a positive effect on biomass growth, controlling its value at a constant set-point during daylight hours can be beneficial in an algae cultivation stage with high algae biomass concentration to maximize the rate of CO2 uptake. The limited enhancement of algal growth by CO2 addition to Hopewell wastewater was due at least in part to the high endogenous CO2 evolution from bacterial degradation of dissolved organic carbon present at high levels in the wastewater. It was found that the high level of bacterial activity was somewhat inhibitory to algal growth in the Hopewell wastewater. The project demonstrated that the Honeywell automation and control system, in combination with the accuracy of the online pH, dissolved O2, dissolved CO2, turbidity, Chlorophyll A and conductivity sensors is suitable for process control of algae cultivation in an open pond systems. This project concluded that the Hopewell wastewater is very suitable for algal cultivation but the potential for significant CO2 sequestration from the plant stack gas emissions was minimal due to the high endogenous CO2 generation in the wastewater from the organic wastewater content. Algae cultivation was found to be promising, however, for nitrogen remediation in the Hopewell wastewater.« less

An X-ray/SDSS sample. II. AGN-driven outflowing gas plasma properties

NASA Astrophysics Data System (ADS)

Perna, M.; Lanzuisi, G.; Brusa, M.; Cresci, G.; Mignoli, M.

2017-10-01

Aims: Galaxy-scale outflows are currently observed in many active galactic nuclei (AGNs); however, characterisation of them in terms of their (multi-) phase nature, amount of flowing material, and effects on their host galaxy is still unresolved. In particular, ionised gas mass outflow rate and related energetics are still affected by many sources of uncertainty. In this respect, outflowing gas plasma conditions, being largely unknown, play a crucial role. Methods: We have analysed stacked spectra and sub-samples of sources with high signal-to-noise temperature- and density-sensitive emission lines to derive the plasma properties of the outflowing ionised gas component. We did this by taking advantage of the spectroscopic analysis results we obtained while studying the X-ray/SDSS sample of 563 AGNs at z < 0.8 presented in our companion paper. For these sources, we also studied in detail various diagnostic diagrams to infer information about outflowing gas ionisation mechanisms. Results: We derive, for the first time, median values for electron temperature and density of outflowing gas from medium-size samples ( 30 targets) and stacked spectra of AGNs. Evidence of shock excitation are found for outflowing gas. Conclusions: We measure electron temperatures of the order of 1.7 × 104 K and densities of 1200 cm-3 for faint and moderately luminous AGNs (intrinsic X-ray luminosity 40.5 < log (LX) < 44 in the 2-10 keV band). We note that the electron density that is usually assumed (Ne = 100 cm-3) in ejected material might result in relevant overestimates of flow mass rates and energetics and, as a consequence, of the effects of AGN-driven outflows on the host galaxy.

Solid oxide fuel cell process and apparatus

DOEpatents

Cooper, Matthew Ellis [Morgantown, WV; Bayless, David J [Athens, OH; Trembly, Jason P [Durham, NC

2011-11-15

Conveying gas containing sulfur through a sulfur tolerant planar solid oxide fuel cell (PSOFC) stack for sulfur scrubbing, followed by conveying the gas through a non-sulfur tolerant PSOFC stack. The sulfur tolerant PSOFC stack utilizes anode materials, such as LSV, that selectively convert H.sub.2S present in the fuel stream to other non-poisoning sulfur compounds. The remaining balance of gases remaining in the completely or near H.sub.2S-free exhaust fuel stream is then used as the fuel for the conventional PSOFC stack that is downstream of the sulfur-tolerant PSOFC. A broad range of fuels such as gasified coal, natural gas and reformed hydrocarbons are used to produce electricity.

23. Brick coke quencher, brick stack, metal stack to right, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

23. Brick coke quencher, brick stack, metal stack to right, coke gas pipe to left; in background, BOF building, limestone piles, Levy's Slag Dump. Looking north/northwest - Rouge Steel Company, 3001 Miller Road, Dearborn, MI

Combustion of peanut and tamarind shells in a conical fluidized-bed combustor: a comparative study.

PubMed

Kuprianov, Vladimir I; Arromdee, Porametr

2013-07-01

Combustion of peanut and tamarind shells was studied in the conical fluidized-bed combustor using alumina sand as the bed material to prevent bed agglomeration. Morphological, thermogravimetric and kinetic characteristics were investigated to compare thermal and combustion reactivity between the biomass fuels. The thermogravimetric kinetics of the biomasses was fitted using the Coats-Redfern method. Experimental tests on the combustor were performed at 60 and 45 kg/h fuel feed rates, with excess air within 20-80%. Temperature and gas concentrations were measured along radial and axial directions in the reactor and at stack. The axial temperature and gas concentration profiles inside the combustor exhibited sensible effects of fuel properties and operating conditions on combustion and emission performance. High (≈ 99%) combustion efficiency and acceptable levels of CO, CxHy, and NO emissions are achievable when firing peanut shells at excess air of about 40%, whereas 60% is more preferable for burning tamarind shells. Copyright © 2013 Elsevier Ltd. All rights reserved.

Vehicle Integrated Photovoltaics for Compression Ignition Vehicles: An Experimental Investigation of Solar Alkaline Water Electrolysis for Improving Diesel Combustion and a Solar Charging System for Reducing Auxiliary Engine Loads

NASA Astrophysics Data System (ADS)

Negroni, Garry Inocentes

Vehicle-integrated photovoltaic electricity can be applied towards aspiration of hydrogen-oxygen-steam gas produced through alkaline electrolysis and reductions in auxiliary alternator load for reducing hydrocarbon emissions in low nitrogen oxide indirect-injection compression-ignition engines. Aspiration of 0.516 ± 0.007 liters-per-minute of gas produced through alkaline electrolysis of potassium-hydroxide 2wt.% improves full-load performance; however, part-load performance decreases due to auto-ignition of aspirated gas prior to top-dead center. Alternator load reductions offer improved part-load and full-load performance with practical limitations resulting from accessory electrical loads. In an additive approach, solar electrolysis can electrochemically convert solar photovoltaic electricity into a gas comprised of stoichiometric hydrogen and oxygen gas. Aspiration of this hydrogen-oxygen gas enhances combustion properties decreasing emissions and increased combustion efficiency in light-duty diesel vehicles. The 316L stainless steel (SS) electrolyser plates are arranged with two anodes and three cathodes space with four bipolar plates delineating four stacks in parallel with five cells per stack. The electrolyser was tested using potassium hydroxide 2 wt.% and hydronium 3wt.% at measured voltage and current inputs. The flow rate output from the reservoir cell was measured in parallel with the V and I inputs producing a regression model correlating current input to flow rate. KOH 2 wt.% produced 0.005 LPM/W, while H9O44 3 wt.% produced less at 0.00126 LPM/W. In a subtractive approach, solar energy can be used to charge a larger energy storage device, as is with plug-in electric vehicles, in order to alleviate the engine of the mechanical load placed upon it by the vehicles electrical accessories through the alternator. Solar electrolysis can improve part-load emissions and full-load performance. The average solar-to-battery efficiency based on the OEM rated efficiency was 11.4%. The average voltage efficiency of the electrolyser during dynamometer testing was 69.16%, producing a solar-to-electrolysis efficiency of 7.88%. At varying engine speeds, HC emissions decreased an average of 54.4% at multiple engine speeds at part-load, while CO2 increased by 2.54% due to oxygen enrichment of intake air. However, the auto-ignition of a small amount of hydrogen (0.0035% of diesel fuel energy) had a negative impact on part-load power (-3.671%) and torque (-3.296%). Full-load sweep testing showed an increase in peak power (1.562%) and peak torque (2.608%). Solar electrolysis gas aspiration reduced soot opacity by 31.5%. The alternator-less part-load step tests show average HC and CO2 emissions decrease on average 25.05% and 1.14% respectively. The test also indicates an increase in average part-load power (1.57%) and torque (2.12%). Alternator-less operation can reduce soot opacity by 56.76%. Full-load testing of the vehicle with alternator unplugged indicates that alternator load upon an engine increase with engine ne speed even with no load and no pilot excitation. Alternator load elimination's performance and emissions improvements should be considered, however, practical limitations exist in winter-night, summer-midday scenarios and for longer duration of operation.

Greenhouse gas accounting of the proposed landfill extension and advanced incineration facility for municipal solid waste management in Hong Kong.

PubMed

Woon, K S; Lo, Irene M C

2013-08-01

The burgeoning of municipal solid waste (MSW) disposal issue and climate change have drawn massive attention from people. On the one hand, Hong Kong is facing a controversial debate over the implementation of proposed landfill extension (LFE) and advanced incineration facility (AIF) to curb the MSW disposal issue. On the other hand, the Hong Kong Special Administrative Region Government is taking concerted efforts to reduce the carbon intensity in this region. This paper discusses the greenhouse gas (GHG) emissions from four proposed waste disposal scenarios, covering the proposed LFE and AIF within a defined system boundary. On the basis of the data collected, assumptions made, and system boundary defined in this study, the results indicate that AIF releases less GHG emissions than LFE. The GHG emissions from LFE are highly contributed by the landfill methane (CH4) emissions but offset by biogenic carbon storage, while the GHG emissions from AIF are mostly due to the stack discharge system but offset by the energy recovery system. Furthermore, parametric sensitivity analyses show that GHG emissions are strongly dependent on the landfill CH4 recovery rate, types of electricity displaced by energy recovery systems, and the heating value of MSW, altering the order of preferred waste disposal scenarios. This evaluation provides valuable insights into the applicability of a policy framework for MSW management practices in reducing GHG emissions. Copyright © 2013 Elsevier B.V. All rights reserved.

Real-time Stack Monitoring at the BaTek Medical Isotope Production Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

McIntyre, Justin I.; Agusbudiman, A.; Cameron, Ian M.

2016-04-01

Radioxenon emissions from radiopharmaceutical production are a major source of background concentrations affecting the radioxenon detection systems of the International Monitoring System (IMS). Collection of real-time emissions data from production facilities makes it possible to screen out some medical isotope signatures from the IMS radioxenon data sets. This paper describes an effort to obtain and analyze real-time stack emissions data with the design, construction and installation of a small stack monitoring system developed by a joint CTBTO-IDC, BATAN, and PNNL team at the BaTek medical isotope production facility near Jakarta, Indonesia.

Compliance Testing of Grissom AFB, Central Heating Plant Coal-Fired Boilers 3, 4 and 5 Grissom AFB, Indiana.

DTIC Science & Technology

1991-03-01

common breeching and can be routed to the wet -scrubber or to a bypass stack. The scrubber is a double-alkali flue - gas desulfurization system using...air. B,,., = proportion by volume of water vapor in F, = a factor representing a ratio of the vol- the stack gas . ume of wet flue gases generated to...1 s- .- - Dtstr’, . iii i Illustrations Figure Title Page 1 View of Scrubbers and Bypass Stack 3 2 Flue Gas Flow Diagram 4 3 ORSAT Sampling Train

Stellar Absorption Line Analysis of Local Star-forming Galaxies: The Relation between Stellar Mass, Metallicity, Dust Attenuation, and Star Formation Rate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jabran Zahid, H.; Kudritzki, Rolf-Peter; Ho, I-Ting

We analyze the optical continuum of star-forming galaxies in the Sloan Digital Sky Survey by fitting stacked spectra with stellar population synthesis models to investigate the relation between stellar mass, stellar metallicity, dust attenuation, and star formation rate. We fit models calculated with star formation and chemical evolution histories that are derived empirically from multi-epoch observations of the stellar mass–star formation rate and the stellar mass–gas-phase metallicity relations, respectively. We also fit linear combinations of single-burst models with a range of metallicities and ages. Star formation and chemical evolution histories are unconstrained for these models. The stellar mass–stellar metallicity relationsmore » obtained from the two methods agree with the relation measured from individual supergiant stars in nearby galaxies. These relations are also consistent with the relation obtained from emission-line analysis of gas-phase metallicity after accounting for systematic offsets in the gas-phase metallicity. We measure dust attenuation of the stellar continuum and show that its dependence on stellar mass and star formation rate is consistent with previously reported results derived from nebular emission lines. However, stellar continuum attenuation is smaller than nebular emission line attenuation. The continuum-to-nebular attenuation ratio depends on stellar mass and is smaller in more massive galaxies. Our consistent analysis of stellar continuum and nebular emission lines paves the way for a comprehensive investigation of stellar metallicities of star-forming and quiescent galaxies.« less

First year operation at New York Power Authority`s 150 MW Richard M. Flynn Combined Cycle Power Station

DOE Office of Scientific and Technical Information (OSTI.GOV)

Medvec, M.D.; Rosen, V.

1995-12-31

In 1990, New York Power Authority (NYPA), was selected to provide 150 MW of electrical power to Long Island Lighting Company (LILCO), using a combined gas and steam turbine cycle. The gas turbine chosen was a Siemens V84.2 with a design ISO rating of 103 MW. NYPA, acting as an independent power producer, would build, operate and maintain the facility. The power plant would be dispatched by LILCO for a period of twenty years from the beginning of its commercial operation on May 1, 1994. The construction was completed in 20 months and the unit started commercial operation on schedule.more » The formal performance acceptance tests, conducted in June 1994, indicated a better net output power and a lower net heart rate than the guaranteed figures for operation with natural gas and light distillate as the backup fuel. Stack emissions compliance tests conducted in October 1995, successfully demonstrated NOx emissions of 9 ppmvd (15% O{sub 2}) for dry combustion of natural gas. In its first year of operation the plant achieved a rolling average equivalent availability rate (EAF) of 94.6%; NYPA`s target is 90.42% for a twenty year contract term. This article will review Siemens NOx abatement technology to obtain single digit emissions and describe the operational experience with the dry low NOx system at the Richard M. Flynn Power Plant.« less

AGE Bio Diesel Emissions Evaluation

DTIC Science & Technology

2003-12-01

329 44 788 Vratd) Standard Meter Volume, m° 1.336 1.214 1.255 1,268 am Average Sampling Rate, dscfm 0786 0 714 0 739 0 746 P, Stack Pressure, inches...sat) Moisture (at saturation), % by volume 70864 248 8 36676 V.d Standard Water Vapor Volume, ft’ 2.198 1 624 1 911 1-B• Dry Mole Fraction 0 941 0946...Clock Meter Dry Gas Sample Time, Volume, Rotameter Meter Temp., Vacuum, Probe Time (min) (24-hr) (liter) Setting (OF) (in.Hg) jTpr, OF /o5 f / 52 / 6 14V_

Comparative analysis between the alveolar recruitment maneuver and breath stacking technique in patients with acute lung injury

PubMed Central

Porto, Elias Ferreira; Tavolaro, Kelly Cristiani; Kumpel, Claudia; Oliveira, Fernanda Augusta; Sousa, Juciaria Ferreira; de Carvalho, Graciele Vieira; de Castro, Antonio Adolfo Mattos

2014-01-01

Objective To compare the effectiveness of the alveolar recruitment maneuver and the breath stacking technique with respect to lung mechanics and gas exchange in patients with acute lung injury. Methods Thirty patients were distributed into two groups: Group 1 - breath stacking; and Group 2 - alveolar recruitment maneuver. After undergoing conventional physical therapy, all patients received both treatments with an interval of 1 day between them. In the first group, the breath stacking technique was used initially, and subsequently, the alveolar recruitment maneuver was applied. Group 2 patients were initially subjected to alveolar recruitment, followed by the breath stacking technique. Measurements of lung compliance and airway resistance were evaluated before and after the use of both techniques. Gas analyses were collected before and after the techniques were used to evaluate oxygenation and gas exchange. Results Both groups had a significant increase in static compliance after breath stacking (p=0.021) and alveolar recruitment (p=0.03), but with no significant differences between the groups (p=0.95). The dynamic compliance did not increase for the breath stacking (p=0.22) and alveolar recruitment (p=0.074) groups, with no significant difference between the groups (p=0.11). The airway resistance did not decrease for either groups, i.e., breath stacking (p=0.91) and alveolar recruitment (p=0.82), with no significant difference between the groups (p=0.39). The partial pressure of oxygen increased significantly after breath stacking (p=0.013) and alveolar recruitment (p=0.04), but there was no significant difference between the groups (p=0.073). The alveolar-arterial O2 difference decreased for both groups after the breath stacking (p=0.025) and alveolar recruitment (p=0.03) interventions, and there was no significant difference between the groups (p=0.81). Conclusion Our data suggest that the breath stacking and alveolar recruitment techniques are effective in improving the lung mechanics and gas exchange in patients with acute lung injury. PMID:25028951

Comparative analysis between the alveolar recruitment maneuver and breath stacking technique in patients with acute lung injury.

PubMed

Porto, Elias Ferreira; Tavolaro, Kelly Cristiani; Kumpel, Claudia; Oliveira, Fernanda Augusta; Sousa, Juciaria Ferreira; Carvalho, Graciele Vieira de; Castro, Antonio Adolfo Mattos de

2014-01-01

To compare the effectiveness of the alveolar recruitment maneuver and the breath stacking technique with respect to lung mechanics and gas exchange in patients with acute lung injury. Thirty patients were distributed into two groups: Group 1 - breath stacking; and Group 2 - alveolar recruitment maneuver. After undergoing conventional physical therapy, all patients received both treatments with an interval of 1 day between them. In the first group, the breath stacking technique was used initially, and subsequently, the alveolar recruitment maneuver was applied. Group 2 patients were initially subjected to alveolar recruitment, followed by the breath stacking technique. Measurements of lung compliance and airway resistance were evaluated before and after the use of both techniques. Gas analyses were collected before and after the techniques were used to evaluate oxygenation and gas exchange. Both groups had a significant increase in static compliance after breath stacking (p=0.021) and alveolar recruitment (p=0.03), but with no significant differences between the groups (p=0.95). The dynamic compliance did not increase for the breath stacking (p=0.22) and alveolar recruitment (p=0.074) groups, with no significant difference between the groups (p=0.11). The airway resistance did not decrease for either groups, i.e., breath stacking (p=0.91) and alveolar recruitment (p=0.82), with no significant difference between the groups (p=0.39). The partial pressure of oxygen increased significantly after breath stacking (p=0.013) and alveolar recruitment (p=0.04), but there was no significant difference between the groups (p=0.073). The alveolar-arterial O2 difference decreased for both groups after the breath stacking (p=0.025) and alveolar recruitment (p=0.03) interventions, and there was no significant difference between the groups (p=0.81). Our data suggest that the breath stacking and alveolar recruitment techniques are effective in improving the lung mechanics and gas exchange in patients with acute lung injury.

40 CFR 60.1775 - What types of stack tests must I conduct?

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 6 2011-07-01 2011-07-01 false What types of stack tests must I...-Stack Testing § 60.1775 What types of stack tests must I conduct? Conduct initial and annual stack tests to measure the emission levels of dioxins/furans, cadmium, lead, mercury, particulate matter, opacity...

40 CFR 60.1775 - What types of stack tests must I conduct?

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 6 2010-07-01 2010-07-01 false What types of stack tests must I...-Stack Testing § 60.1775 What types of stack tests must I conduct? Conduct initial and annual stack tests to measure the emission levels of dioxins/furans, cadmium, lead, mercury, particulate matter, opacity...

Modeling and Qualification of a Modified Emission Unit for Radioactive Air Emissions Stack Sampling Compliance.

PubMed

Barnett, J Matthew; Yu, Xiao-Ying; Recknagle, Kurtis P; Glissmeyer, John A

2016-11-01

A planned laboratory space and exhaust system modification to the Pacific Northwest National Laboratory Material Science and Technology Building indicated that a new evaluation of the mixing at the air sampling system location would be required for compliance to ANSI/HPS N13.1-2011. The modified exhaust system would add a third fan, thereby increasing the overall exhaust rate out the stack, thus voiding the previous mixing study. Prior to modifying the radioactive air emissions exhaust system, a three-dimensional computational fluid dynamics computer model was used to evaluate the mixing at the sampling system location. Modeling of the original three-fan system indicated that not all mixing criteria could be met. A second modeling effort was conducted with the addition of an air blender downstream of the confluence of the three fans, which then showed satisfactory mixing results. The final installation included an air blender, and the exhaust system underwent full-scale tests to verify velocity, cyclonic flow, gas, and particulate uniformity. The modeling results and those of the full-scale tests show agreement between each of the evaluated criteria. The use of a computational fluid dynamics code was an effective aid in the design process and allowed the sampling system to remain in its original location while still meeting the requirements for sampling at a well mixed location.

Effect of stacking faults on the photoluminescence spectrum of zincblende GaN

NASA Astrophysics Data System (ADS)

Church, S. A.; Hammersley, S.; Mitchell, P. W.; Kappers, M. J.; Lee, L. Y.; Massabuau, F.; Sahonta, S. L.; Frentrup, M.; Shaw, L. J.; Wallis, D. J.; Humphreys, C. J.; Oliver, R. A.; Binks, D. J.; Dawson, P.

2018-05-01

The photoluminescence spectra of a zincblende GaN epilayer grown via metal-organic chemical vapour deposition upon 3C-SiC/Si (001) substrates were investigated. Of particular interest was a broad emission band centered at 3.4 eV, with a FWHM of 200 meV, which extends above the bandgap of both zincblende and wurtzite GaN. Photoluminescence excitation measurements show that this band is associated with an absorption edge centered at 3.6 eV. Photoluminescence time decays for the band are monoexponential, with lifetimes that reduce from 0.67 ns to 0.15 ns as the recombination energy increases. TEM measurements show no evidence of wurtzite GaN inclusions which are typically used to explain emission in this energy range. However, dense stacking fault bunches are present in the epilayers. A model for the band alignment at the stacking faults was developed to explain this emission band, showing how both electrons and holes can be confined adjacent to stacking faults. Different stacking fault separations can change the carrier confinement energies sufficiently to explain the width of the emission band, and change the carrier wavefunction overlap to account for the variation in decay time.

Ambient pressure fuel cell system

DOEpatents

Wilson, Mahlon S.

2000-01-01

An ambient pressure fuel cell system is provided with a fuel cell stack formed from a plurality of fuel cells having membrane/electrode assemblies (MEAs) that are hydrated with liquid water and bipolar plates with anode and cathode sides for distributing hydrogen fuel gas and water to a first side of each one of the MEAs and air with reactant oxygen gas to a second side of each one of the MEAs. A pump supplies liquid water to the fuel cells. A recirculating system may be used to return unused hydrogen fuel gas to the stack. A near-ambient pressure blower blows air through the fuel cell stack in excess of reaction stoichiometric amounts to react with the hydrogen fuel gas.

A CANDELS WFC3 Grism Study of Emission-Line Galaxies at Z approximates 2: A mix of Nuclear Activity and Low-Metallicity Star Formation

NASA Technical Reports Server (NTRS)

Trump, Jonathan R.; Weiner, Benjamin J.; Scarlata, Claudia; Kocevski, Dale D.; Bell, Eric F.; McGrath, Elizabeth J.; Koo, David C.; Faber, S. M.; Laird, Elise S.; Mozena, Mark;

Gas kinematics of Lyman Alpha Blobs at z=2-3

NASA Astrophysics Data System (ADS)

Yang, Yujin

2015-08-01

High-redshift Lyman alpha nebulae (Ly-alpha "blobs", LABs) are the site of massive galaxy formation and their early interaction with the intergalactic medium. Research in the past decade has struggled to make progress on the question of what powers these huge Ly-alpha halos and whether the Ly-alpha-emitting gas is outflowing or infalling. First, I will present our optical and NIR spectroscopic observations for the Ly-alpha and the redshifted nebular emission lines such as [OII], [OIII] and Halpha. Using three independent measures --- the velocity offset between the Ly-alpha line and the nonresonant [O III] or Halpha line, the offset of stacked interstellar metal absorption lines, and the spectrally resolved [O III] line profile --- we study the kinematics of gas along the line of sight to galaxies within each blob center. All these kinematic measures show that there are only weak outflows, therefore excluding gas inflows and extreme hyper/superwinds as a source of the extended Ly-alpha emission. I will also present the first detection of molecular gas from a Ly-alpha blob and our on-going effort to characterize the physical conditions of its ISM. The large velocity gradient (LVG) modeling using PdBI observations of CO(3-2), CO(5-4), CO(7-6), CI(2-1) lines suggests that two-phase medium is required to explain the blob's CO SEDs and dust continuum.

Performance of a Retrofitted Multicyclone for PM2.5 Emission Control

NASA Astrophysics Data System (ADS)

Dewika, M.; Rashid, M.; Ammar, M. R.

2018-03-01

This paper presents on the performance of a retrofitted multicyclone system, which aims to increase the collection efficiency of PM2.5 (i.e. particulate size fraction ≤ 2.5 μm) emission. The multicyclone was retrofitted by extracting 15% and 20% of the total volumetric air flow rate at the dust hopper of the unit using an additional Induced Draft Fan. The total collection efficiency with and without the extraction was measured at various air volumetric flow rates and particulate mass inlet concentration. The results showed that there was a reduction of 12% to 54% depending on the inlet concentration of PM2.5 emission in the stack with compared to without extraction increasing the collection efficiency of the retrofitted multicyclone. The finding suggests that a simple technique of applying gas extraction at the dust hopper of a multicyclone as reported in this study able to increase the overall performance in fine particulate collection.

Differential Absorption Lidar (DIAL) Measurements of Landfill Methane Emissions

NASA Astrophysics Data System (ADS)

Innocenti, Fabrizio; Robinson, Rod; Gardiner, Tom; Finlayson, Andrew; Connor, Andy

2017-04-01

DIFFERENTIAL ABSORPTION LIDAR (DIAL) MEASURMENTS OF LANDFILL METHANE EMISSIONS F. INNOCENTI *, R.A. ROBINSON *, T.D. GARDINER, A. FINLAYSON *, A. CONNOR* * National Physical Laboratory (NPL), Hampton Road, Teddington, Middlesex, TW11 0LW, United Kingdom Methane is one of the most important gaseous hydrocarbon species for both industrial and environmental reasons. Understanding and quantifying methane emissions to atmosphere is an important element of climate change research. Range-resolved infrared Differential Absorption Lidar (DIAL) measurements provide the means to map and quantify a wide range of different methane sources. DIAL is a powerful technique that can be used to track and quantify plumes emitted from area emission sources such as landfill sites, waste water treatment plants and petrochemical plants. By using lidar (light detection and ranging), the DIAL technique is able to make remote range-resolved single-ended measurements of the actual distribution of target gases in the atmosphere, with no disruption to normal site operational activities. DIAL provides 3D mapping of emission concentrations and quantification of emission rates for a wide range of target gases such as methane. The NPL DIAL laser source is operated alternately at two similar wavelengths. One of these, termed the "on-resonant wavelength", is chosen to be at a wavelength which is absorbed by the target species. The other, the "off-resonant wavelength", is chosen to be at a nearby wavelength which is not absorbed significantly by the target species. The two wavelengths are chosen to be close, so that the atmospheric scattering properties are the same for both wavelengths. They are also chosen so that any differential absorption due to other atmospheric species are minimised. Any measured difference in the returned signals is therefore due to absorption by the target gas. In the typical DIAL measurement configuration the mobile DIAL facility is positioned downwind of the area being investigated. The DIAL laser beam is then scanned in a vertical plane and the distribution of the target gas in the measurement plane is mapped. By combining this information with the wind conditions, the technique provides a direct measure of the emission rate of the target gas and its spatial distribution rather than the path-averaged concentration given by most other optical remote sensing methods. This means that localised, high concentration plumes can be discriminated from broad, low concentration plumes, and that emissions from different sources within an area can be spatially separated and independently quantified. As an example, the localised emission from an engine stack or flare can be separated from the diffuse emission from a capped area. Horizontal scans just above the surface can also be performed and they are generally used to identify emission hot-spots. Over the last decade the NPL DIAL system has carried out landfill emission surveys at over thirty sites in the UK, France and the USA measuring the total site and area-specific emissions from e.g. active areas, capped areas and engine stacks. This history of emissions measurements made with DIAL at landfill sites is testament to the maturity of the technique that can be deployed as reference tool by the waste industry. The DIAL data can be used by the site operators to validate emissions estimates and by the regulators to revise and update the emission inventories.

40 CFR 63.9882 - What parts of my plant does this subpart cover?

Code of Federal Regulations, 2010 CFR

2010-07-01

... CATEGORIES (CONTINUED) National Emissions Standards for Hazardous Air Pollutants for Primary Magnesium... affected sources are each new and existing primary magnesium refining facility. (b) This subpart covers emissions from each spray dryer stack, magnesium chloride storage bins scrubber stack, melt/reactor system...

40 CFR 63.9882 - What parts of my plant does this subpart cover?

Code of Federal Regulations, 2012 CFR

2012-07-01

... CATEGORIES (CONTINUED) National Emissions Standards for Hazardous Air Pollutants for Primary Magnesium... affected sources are each new and existing primary magnesium refining facility. (b) This subpart covers emissions from each spray dryer stack, magnesium chloride storage bins scrubber stack, melt/reactor system...

40 CFR 63.9882 - What parts of my plant does this subpart cover?

Code of Federal Regulations, 2014 CFR

2014-07-01

... CATEGORIES (CONTINUED) National Emissions Standards for Hazardous Air Pollutants for Primary Magnesium... affected sources are each new and existing primary magnesium refining facility. (b) This subpart covers emissions from each spray dryer stack, magnesium chloride storage bins scrubber stack, melt/reactor system...

40 CFR 63.9882 - What parts of my plant does this subpart cover?

Code of Federal Regulations, 2011 CFR

2011-07-01

... CATEGORIES (CONTINUED) National Emissions Standards for Hazardous Air Pollutants for Primary Magnesium... affected sources are each new and existing primary magnesium refining facility. (b) This subpart covers emissions from each spray dryer stack, magnesium chloride storage bins scrubber stack, melt/reactor system...

40 CFR 63.9882 - What parts of my plant does this subpart cover?

Code of Federal Regulations, 2013 CFR

2013-07-01

... CATEGORIES (CONTINUED) National Emissions Standards for Hazardous Air Pollutants for Primary Magnesium... affected sources are each new and existing primary magnesium refining facility. (b) This subpart covers emissions from each spray dryer stack, magnesium chloride storage bins scrubber stack, melt/reactor system...

Unravelling the Chemical Complexity of Biomass Burning VOC Emissions via H3O+ ToF-CIMS: Separation of High- and Low-temperature Pyrolysis Products

NASA Astrophysics Data System (ADS)

Sekimoto, K.; Koss, A.; Gilman, J.; Selimovic, V.; Coggon, M.; Zarzana, K. J.; Yuan, B.; Lerner, B. M.; Brown, S. S.; Warneke, C.; Yokelson, R. J.; De Gouw, J. A.

2017-12-01

Biomass burning is a large source of volatile organic compounds (VOCs) and many other trace species to the atmosphere. These VOCs can act as precursors to formation of secondary pollutants such as ozone and fine particles, and some VOCs can also have direct effects on human and ecosystem health. Multiple different and complex processes take place in biomass burning, e.g., distillation, flaming, and smoldering combustion processes. In a given fire, most of these processes occur simultaneously, but the relative importance of each can change over the course of a fire. This gives rise to some of the variability in VOC emissions between different fires. To study gas-phase emissions from biomass burning, an H3O+ ToF-CIMS was deployed during the FIREX 2016 laboratory intensive at the US Forest Service Fire Sciences Laboratory in Missoula, Montana. This instrument has a fast time response and the measurements in stack burns show the varying gas-phase emissions as the mix of distillation, flaming, and smoldering varies. We used positive matrix factorization (PMF) to reduce and explain the observed chemical complexity in the gas phase. Despite the complexity and variability of emissions, we found that a solution including just two emission profiles explained on average 85% of the VOC emissions across 15 different fuel types including pines, firs, spruce, grass, shrubs, chaparrals, and wood wool. We identified the two profiles as resulting from high-temperature and low-temperature pyrolysis processes, and found that the profiles were remarkably similar (correlation coefficient r > 0.9) across nearly all the fuel types described above. Some of the remaining differences in VOC emission profiles between fuel types, and exceptions to the two-profile solution, can be explained by differences in the chemical composition of the fuels.

Volatile organic compounds (VOCs) emission characteristics and control strategies for a petrochemical industrial area in middle Taiwan.

PubMed

Yen, Chia-Hsien; Horng, Jao-Jia

2009-11-01

This study investigated VOC emissions from the largest petrochemical industrial district in Taiwan and recommended some control measures to reduce VOC emissions. In addition to the petrochemical industry, the district encompasses a chemical and fiber industry, a plastics industry and a harbor, which together produce more than 95% of the VOC emissions in the area. The sequence of VOC emission was as follows: components (e.g., valves, flanges, and pumps) (47%) > tanks (29%) > stacks (15%) > wastewater treatment facility (6%) > loading (2%) > flares (1%). Other plants producing high-density polyethylene (HDPE), styrene, ethylene glycol (EG), gas oil, and iso-nonyl-alchol (INA) were measured to determine the VOC leaching in the district. The VOC emissions of these 35 plants (90% of all plants) were less than 100 tons/year. About 74% of the tanks were fixed-roof tanks that leached more VOCs than the other types of tanks. To reduce leaching, the components should be checked periodically, and companies should be required to follow the Taiwan EPA regulations. A VOC emission management system was developed in state implementation plans (SIPs) to inspect and reduce emissions in the industrial district.

The Direct FuelCell™ stack engineering

NASA Astrophysics Data System (ADS)

Doyon, J.; Farooque, M.; Maru, H.

FuelCell Energy (FCE) has developed power plants in the size range of 300 kW to 3 MW for distributed power generation. Field-testing of the sub-megawatt plants is underway. The FCE power plants are based on its Direct FuelCell™ (DFC) technology. This is so named because of its ability to generate electricity directly from a hydrocarbon fuel, such as natural gas, by reforming it inside the fuel cell stack itself. All FCE products use identical 8000 cm 2 cell design, approximately 350-400 cells per stack, external gas manifolds, and similar stack compression systems. The difference lies in the packaging of the stacks inside the stack module. The sub-megawatt system stack module contains a single horizontal stack whereas the MW-class stack module houses four identical vertical stacks. The commonality of the design, internal reforming features, and atmospheric operation simplify the system design, reduce cost, improve efficiency, increase reliability and maintainability. The product building-block stack design has been advanced through three full-size stack operations at company's headquarters in Danbury, CT. The initial proof-of-concept of the full-size stack design was verified in 1999, followed by a 1.5 year of endurance verification in 2000-2001, and currently a value-engineered stack version is in operation. This paper discusses the design features, important engineering solutions implemented, and test results of FCE's full-size DFC stacks.

[Emission and source characterization of monoaromatic hydrocarbons from coke production].

PubMed

He, Qiu-Sheng; Wang, Xin-Ming; Sheng, Guo-Ying; Fu, Jia-Mo

2005-09-01

Monoaromatic hydrocarbons (MAHs) from indigenous and industrial coking processes are studied in Shanxi province. They are sampled on the top of coke ovens and in the chimneys using stainless steel canister and determined by GC/MSD after preconcentration with liquid nitrogen. Benzene, toluene and xylene are the main components among MAHs emitted from coking processes. Benzene and the total MAHs concentrations were as high as 3421.0 microg/m3 and 4 865.9 microg/m3 in the air from indigenous coking, 548.7 microg/m3 and 1 054.8 microg/m3 in the oventop air from industrial coking, and 1 376.4 microg/m3 and 1 819.4 microg/m3 in stack gas from industrial coking, respectively. The MAHs concentrations vary greatly during the indigenous coking process, which in the prophase (from firing to 10 days) is obviously higher than in the anaphase (10 days to quenching the coke). In industrial coking the MAHs in the oventop air are highest when charging the coal and next when transferring the hot coke, but in stack gas they are highest when charging coal and lowest when transferring the coke. Benzene, toluene, ethylbenzene and xylene (BTEX) in industrial coking samples show good linearity, indicating that MAHs in industrial coking might come predominantly from coal pyrolysis; but BTEX distribute dispersedly in indigenous coking samples, indicating that its emission might be affected by many factors. In all samples BTEX ratios especially high B/E ratio, is unique among MAHs sources, and might be helpful to characterize pollution from coking.

Stack Gas Scrubber Makes the Grade

ERIC Educational Resources Information Center

Chemical and Engineering News, 1975

1975-01-01

Describes a year long test of successful sulfur dioxide removal from stack gas with a calcium oxide slurry. Sludge disposal problems are discussed. Cost is estimated at 0.6 mill per kwh not including sludge removal. A flow diagram and equations are included. (GH)

Greenhouse gas emissions from dairy open lot and manure stockpile in northern China: A case study.

PubMed

Ding, Luyu; Lu, Qikun; Xie, Lina; Liu, Jie; Cao, Wei; Shi, Zhengxiang; Li, Baoming; Wang, Chaoyuan; Zhang, Guoqiang; Ren, Shixi

2016-03-01

The open lots and manure stockpiles of dairy farm are major sources of greenhouse gas (GHG) emissions in typical dairy cow housing and manure management system in China. GHG (CO(2), CH(4) and N(2)O) emissions from the ground level of brick-paved open lots and uncovered manure stockpiles were estimated according to the field measurements of a typical dairy farm in Beijing by closed chambers in four consecutive seasons. Location variation and manure removal strategy impacts were assessed on GHG emissions from the open lots. Estimated CO(2), CH(4) and N(2)O emissions from the ground level of the open lots were 137.5±64.7 kg hd(-1) yr(-1), 0.45±0.21 kg hd(-1) yr(-1) and 0.13±0.08 kg hd(-1) yr(-1), respectively. There were remarkable location variations of GHG emissions from different zones (cubicle zone vs. aisle zone) of the open lot. However, the emissions from the whole open lot were less affected by the locations. After manure removal, lower CH(4) but higher N(2)O emitted from the open lot. Estimated CO(2), CH(4) and N(2)O emissions from stockpile with a stacking height of 55±12 cm were 858.9±375.8 kg hd(-1) yr(-1), 8.5±5.4 kg hd(-1) yr(-1) and 2.3±1.1 kg hd(-1) yr(-1), respectively. In situ storage duration, which estimated by manure volatile solid contents (VS), would affect GHG emissions from stockpiles. Much higher N(2)O was emitted from stockpiles in summer due to longer manure storage. This study deals with greenhouse gas (GHG) emissions from open lots and stockpiles. It's an increasing area of concern in some livestock producing countries. The Intergovernmental Panel on Climate Change (IPCC) methodology is commonly used for estimation of national GHG emission inventories. There is a shortage of on-farm information to evaluate the accuracy of these equations and default emission factors. This work provides valuable information for improving accounting practices within China or for similar manure management practice in other countries.

40 CFR 62.15250 - May I conduct stack testing less often?

Code of Federal Regulations, 2010 CFR

2010-07-01

... pollutants subject to stack testing requirements: dioxins/furans, cadmium, lead, mercury, particulate matter, opacity, hydrogen chloride, and fugitive ash. (b) You can test less often for dioxins/furans emissions if... municipal waste combustion units have demonstrated levels of dioxins/furans emissions less than or equal to...

Distribution of PCDD/Fs in the fly ash and atmospheric air of two typical hazardous waste incinerators in eastern China.

PubMed

Chen, Tong; Zhan, Ming-Xiu; Lin, Xiao-Qing; Fu, Jian-Ying; Lu, Sheng-Yong; Li, Xiao-Dong

2015-01-01

Distribution of polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs) in the fly ash and atmospheric air of one medical waste incinerator (MWI) and one industrial hazardous waste incinerator (IHWI) plants were characterized. The PCDD/F concentrations of the stack gas (fly ash) produced from MWI and IHWI were 17.7 and 0.7 ng international toxic equivalent (I-TEQ)/Nm(3) (4.1 and 2.5 ng I-TEQ/g), respectively. For workplace air, the total concentrations of PCDD/Fs were 11.32 and 0.28 pg I-TEQ/Nm(3) (819.5 and 15.3 pg/Nm(3)). We assumed that the large differences of PCDD/F concentrations in workplace air were due to the differences in chlorine content of the waste, combustion conditions, and other contamination sources. With respect to the homologue profiles, the concentrations of PCDFs decreased with the increase of the substituted chlorine number for each site. Among all of the PCDD/F congeners, 2,3,4,7,8-PeCDF was the most important contributor to the I-TEQ value accounting for ca. 43 % of two sites. The gas/particle partition of PCDD/Fs in the atmosphere of the workplace in the MWI was also investigated, indicating that PCDD/Fs were more associated in the particle phase, especially for the higher chlorinated ones. Moreover, the ratio of the I-TEQ values in particle and gas phase of workplace air was 11.0. At last, the relationship between the distribution of PCDD/Fs in the workplace air and that from stack gas and fly ash was also analyzed and discussed. The high correlation coefficient might be a sign for diffuse gas emissions at transient periods of fumes escaping from the incinerator.

Individually addressable cathodes with integrated focusing stack or detectors

DOEpatents

Thomas, Clarence E.; Baylor, Larry R.; Voelkl, Edgar; Simpson, Michael L.; Paulus, Michael J.; Lowndes, Douglas; Whealton, John; Whitson, John C.; Wilgen, John B.

2005-07-12

Systems and method are described for addressable field emission array (AFEA) chips. A plurality of individually addressable cathodes are integrated with an electrostatic focusing stack and/or a plurality of detectors on the addressable field emission array. The systems and methods provide advantages including the avoidance of space-charge blow-up.

Circularly polarized luminescence of helically assembled pyrene π-stacks on RNA and DNA duplexes.

PubMed

Nakamura, Mitsunobu; Ota, Fuyuki; Takada, Tadao; Akagi, Kazuo; Yamana, Kazushige

2018-05-01

In this report, we describe the circularly polarized luminescence (CPL) of the RNA duplexes having one to four 2'-O-pyrene modified uridines (Upy) and the DNA duplexes having two, four, and six pyrene modified non-nucleosidic linkers (Py). Both the pyrene π-stack arrays formed on the RNA and DNA double helical structures exhibited pyrene excimer fluorescence. In the pyrene-modified RNA systems, the RNA duplex having four Upys gives CPL emission with g lum value of <0.01 at 480 nm. The structure of pyrene stacks on the RNA duplex may be rigidly regulated with increase in the Upy domains, which resulted in the CPL emission. In the DNA systems, the pyrene-modified duplexes containing two and four Pys exhibited CPL emission with g lum values of <0.001 at 505 nm. The pyrene π-stack arrays presented here show CPL emission. However, the g lum values are relatively small when compared with our previous system consisting of the pyrene-zipper arrays on RNA. © 2018 Wiley Periodicals, Inc.

Coal-fired power generaion, new air quality regulations, and future U.S. coal production

USGS Publications Warehouse

Attanasi, E.D.; Root, D.H.

1999-01-01

Tighter new regulation of stack gas emissions and competition in power generation are driving electrical utilities to demand cleaner, lower sulfur coal. Historical data on sulfur content of produced coals shows little variability in coal quality for individual mines and individual coal-producing counties over relatively long periods of time. If coal-using power generators follow the compliance patterns established in Phase I of the 1990 Clean Air Act Amendments, then the industry's response to the tighter Phase II emissions standards will result in large amounts of coal production shifting from higher sulfur areas to areas with lower cost low sulfur coal. One reason this shift will likely occur is that currently only 30% of U.S. coal-fired electrical generating capacity is equipped with flue-gas scrubbers. In 1995, coal mines in the higher sulfur areas of the Illinois Basin and Northern and Central Appalachia employed 78% of all coal miners (>70,000 miners). A substantial geographical redistribution of the nation's coal supplies will likely lead to economic dislocations that will reach beyond local coal-producing areas.

[Atmospheric emission of PCDD/Fs from modern dry processing cement kilns with preheating in the southwest area, China].

PubMed

Zhang, Xiao-Ling; Lu, Yi; Jian, Chuan; Guo, Zhi-Shun; Zhu, Ming-Ji; Deng, Li; Sun, Jing; Zhang, Qin

2014-01-01

Six cement kilns were measured for emissions of PCDD/Fs in the Southwest Area, China. The results indicated that the emission levels of PCDD/Fs were 0.0029-0.0062 ng-m(-3) (Average, 0.0043 ng X m(-3)) from cement kilns which did not burn solid waste, and 0.028 ng X m(-3) from co-processing sewage sludge in cement kiln. The levels of PCDD/Fs emissions from cement manufacturing in the Southwest Area were significantly below the national emissions standard (0.1 ng x m(-3)). Emission factors of PCDD/Fs from the six cement kilns varied between 0.0089 and 0.084 microg x t(-1) cement, which were near or below the lowest emission factor reported by UNEP in 2005. Moreover, the emission factor of PCDD/Fs from co-processing sewage sludge in cement kiln was 7.6 times of the average factors from the other five cement kilns. Moreover,congener distribution of PCDD/F in stack gas from the two types of cement kilns was very different. The results showed that modern dry process cement kilns with preheating have lower emissions of PCDD/Fs. This suggested that the product of co-processing solid waste in cement kilns should be largely enhanced in China in future.

OPERATING PARAMETERS TO MINIMIZE EMISSIONS DURING ROTARY KILN EMERGENCY SAFETY VENT OPENINGS

EPA Science Inventory

Certain designs of hazardous waste incinerator systems include emergency safety vents (ESVs). ESVs (also called dump stacks, vent stacks, emergency by-pass stacks, thermal relief valves, and pressure relief valves) are regarded as true emergency devices. Their purpose is to vent ...

Health-care waste incineration and related dangers to public health: case study of the two teaching and referral hospitals in Kenya.

PubMed

Njagi, Nkonge A; Oloo, Mayabi A; Kithinji, J; Kithinji, Magambo J

2012-12-01

There are practically no low cost, environmentally friendly options in practice whether incineration, autoclaving, chemical treatment or microwaving (World Health Organisation in Health-care waste management training at national level, [2006] for treatment of health-care waste. In Kenya, incineration is the most popular treatment option for hazardous health-care waste from health-care facilities. It is the choice practiced at both Kenyatta National Hospital, Nairobi and Moi Teaching and Referral Hospital, Eldoret. A study was done on the possible public health risks posed by incineration of the segregated hazardous health-care waste in one of the incinerators in each of the two hospitals. Gaseous emissions were sampled and analyzed for specific gases the equipment was designed and the incinerators Combustion efficiency (CE) established. Combustion temperatures were also recorded. A flue gas analyzer (Model-Testos-350 XL) was used to sample flue gases in an incinerator under study at Kenyatta National Hospital--Nairobi and Moi Teaching and Referral Hospital--Eldoret to assess their incineration efficiency. Flue emissions were sampled when the incinerators were fully operational. However the flue gases sampled in the study, by use of the integrated pump were, oxygen, carbon monoxide, nitrogen dioxide, nitrous oxide, sulphur dioxide and No(x). The incinerator at KNH operated at a mean stack temperature of 746 °C and achieved a CE of 48.1 %. The incinerator at MTRH operated at a mean stack temperature of 811 °C and attained a CE of 60.8 %. The two health-care waste incinerators achieved CE below the specified minimum National limit of 99 %. At the detected stack temperatures, there was a possibility that other than the emissions identified, it was possible that the two incinerators tested released dioxins, furans and antineoplastic (cytotoxic drugs) fumes should the drugs be subjected to incineration in the two units.

Volatile organic compound analysis in wood combustion and meat cooking emissions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zielinska, B.; McDonald, J.

1999-07-01

Residential wood combustion and meat cooking emissions were each analyzed for volatile organic compounds (VOC). Emissions were diluted 60--100 times, cooled to ambient temperature, and allowed 80 seconds for condensation prior to collection with the aid of a DRI-constructed dilution stack sampler. Fireplace and wood-stove emissions testing was conducted at the DRI facilities. Wood type, wood moisture, burn rate, and fuel load were varied for different experiments. Meat emissions testing was conducted at the CE-CERT stationary emissions lab, University of California, Riverside. Meat type, fat content, and cooking appliance were changed in different tests. VOCs were collected using stainless-steel 6more » L canisters and Tenax cartridges, whereas for carbonyl compound collection 2,4-dinitrophenylhydrazine (DNPH)-impregnated C{sub 18} SepPack cartridges were used. Analysis of VOC collected with canisters and Tenax cartridges was conducted by Gas Chromatography/Mass Spectrometry (GC/MS) and by GC/FID/ECD (flame ionization detection/electron capture detection). DNPH-impregnated cartridges were analyzed for fourteen C{sub 1}--C{sub 7} carbonyl compounds, using the HPLC method. The results of these measurements are discussed.« less

Source apportionment of stack emissions from research and development facilities using positive matrix factorization

NASA Astrophysics Data System (ADS)

Ballinger, Marcel Y.; Larson, Timothy V.

2014-12-01

Research and development (R&D) facility emissions are difficult to characterize due to their variable processes, changing nature of research, and large number of chemicals. Positive matrix factorization (PMF) was applied to volatile organic compound (VOC) concentrations measured in the main exhaust stacks of four different R&D buildings to identify the number and composition of major contributing sources. PMF identified between 9 and 11 source-related factors contributing to stack emissions, depending on the building. Similar factors between buildings were major contributors to trichloroethylene (TCE), acetone, and ethanol emissions; other factors had similar profiles for two or more buildings but not all four. At least one factor for each building was identified that contained a broad mix of many species and constraints were used in PMF to modify the factors to resemble more closely the off-shift concentration profiles. PMF accepted the constraints with little decrease in model fit.

40 CFR 266.105 - Standards to control particulate matter.

Code of Federal Regulations, 2011 CFR

2011-07-01

... standard cubic foot) after correction to a stack gas concentration of 7% oxygen, using procedures... particulate matter standard. (c) Oxygen correction. (1) Measured pollutant levels must be corrected for the amount of oxygen in the stack gas according to the formula: ER30SE99.027 Where: Pc is the corrected...

40 CFR 266.105 - Standards to control particulate matter.

Code of Federal Regulations, 2013 CFR

2013-07-01

... standard cubic foot) after correction to a stack gas concentration of 7% oxygen, using procedures... particulate matter standard. (c) Oxygen correction. (1) Measured pollutant levels must be corrected for the amount of oxygen in the stack gas according to the formula: ER30SE99.027 Where: Pc is the corrected...

40 CFR 266.105 - Standards to control particulate matter.

Code of Federal Regulations, 2012 CFR

2012-07-01

... standard cubic foot) after correction to a stack gas concentration of 7% oxygen, using procedures... particulate matter standard. (c) Oxygen correction. (1) Measured pollutant levels must be corrected for the amount of oxygen in the stack gas according to the formula: ER30SE99.027 Where: Pc is the corrected...

40 CFR 266.105 - Standards to control particulate matter.

Code of Federal Regulations, 2014 CFR

2014-07-01

... standard cubic foot) after correction to a stack gas concentration of 7% oxygen, using procedures... particulate matter standard. (c) Oxygen correction. (1) Measured pollutant levels must be corrected for the amount of oxygen in the stack gas according to the formula: ER30SE99.027 Where: Pc is the corrected...

40 CFR 63.1656 - Performance testing, test methods, and compliance demonstrations.

Code of Federal Regulations, 2012 CFR

2012-07-01

... points. (2) Method 2 to determine the volumetric flow rate of the stack gas. (3) Method 3 to determine... matter concentration and volumetric flow rate of the stack gas for positive pressure baghouses without...) Determine the particulate matter concentration and volumetric flow rate using Method 5 or 5D, as applicable...

40 CFR 63.1656 - Performance testing, test methods, and compliance demonstrations.

Code of Federal Regulations, 2013 CFR

2013-07-01

... points. (2) Method 2 to determine the volumetric flow rate of the stack gas. (3) Method 3 to determine... matter concentration and volumetric flow rate of the stack gas for positive pressure baghouses without...) Determine the particulate matter concentration and volumetric flow rate using Method 5 or 5D, as applicable...

40 CFR 63.1656 - Performance testing, test methods, and compliance demonstrations.

Code of Federal Regulations, 2014 CFR

2014-07-01

... points. (2) Method 2 to determine the volumetric flow rate of the stack gas. (3) Method 3 to determine... matter concentration and volumetric flow rate of the stack gas for positive pressure baghouses without...) Determine the particulate matter concentration and volumetric flow rate using Method 5 or 5D, as applicable...

Evaluation of Gas-Cooled Pressurized Phosphoric Acid Fuel Cells for Electric Utility Power Generation

NASA Technical Reports Server (NTRS)

Faroque, M.

1983-01-01

Gas cooling is a more reliable, less expensive and a more simple alternative to conventional liquid cooling for heat removal from the phosphoric acid fuel cell (PAFC). The feasibility of gas-cooling was already demonstrated in atmospheric pressure stacks. Theoretical and experimental investigations of gas-cooling for pressurized PAFC are presented. Two approaches to gas cooling, Distributed Gas-Cooling (DIGAS) and Separated Gas-Cooling (SGC) were considered, and a theoretical comparison on the basis of cell performance indicated SGC to be superior to DIGAS. The feasibility of SGC was experimentally demonstrated by operating a 45-cell stack for 700 hours at pressure, and determining thermal response and the effect of other related parameters.

40 CFR 61.203 - Radon monitoring and compliance procedures.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 8 2010-07-01 2010-07-01 false Radon monitoring and compliance... for Radon Emissions From Phosphogypsum Stacks § 61.203 Radon monitoring and compliance procedures. (a..., each owner or operator of an inactive phosphogypsum stack shall test the stack for radon-222 flux in...

40 CFR 61.203 - Radon monitoring and compliance procedures.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 8 2011-07-01 2011-07-01 false Radon monitoring and compliance... for Radon Emissions From Phosphogypsum Stacks § 61.203 Radon monitoring and compliance procedures. (a..., each owner or operator of an inactive phosphogypsum stack shall test the stack for radon-222 flux in...

[Progress in microalgae culture system for biodiesel combined with reducing carbon dioxide emission].

PubMed

Su, Hongyang; Zhou, Xuefei; Xia, Xuefen; Sun, Zhen; Zhang, Yalei

2011-09-01

Wastewater resources, CO2 emission reduction and microalgae biodiesel are considered as current frontier fields of energy and environmental researches. In this paper, we reviewed the progress in system of microalgae culture for biodiesel production by wastewater and stack gas. Multiple factors including microalgal species, nutrition, culture methods and photobioreactor, which were crucial to the cultivation of microalgae for biodiesel production, were discussed in detail. A valuable culture system of microalgae for biodiesel production or other high value products combined with the treatment of wastewater by microalgae was put forward through the optimizations of algal species and culture technology. The culture system coupled with the treatment of wastewater, the reduction of CO2 emission with the cultivation of microalgae for biodiesel production will reduce the production cost of microalgal biofuel production and the treatment cost of wastewater simultaneously. Therefore, it would be a promising technology with important environmental value, social value and economic value to combine the treatment of wastewater with the cultivation of microalgae for biodiesel production.

[Analysis on Mechanism of Rainout Carried by Wet Stack of Thermal Power Plant].

PubMed

Ouyang, Li-hua; Zhuang, Ye; Liu, Ke-wei; Chen, Zhen-yu; Gu, Peng

2015-06-01

Rainout from wet-stack took placed in many thermal power plants with WFGD system. Research on causes of the rainout is important to solve the problem. The objective of this research is to analyze the mechanism of rainout. Field study was performed to collect experimental data in one thermal power plant, including the amount of desulfurization slurry carried by wet flue gas, liquor condensate from wet duct, and droplets from the wet stack. Source apportionment analysis was carried out based on physical and chemical data of liquid sample and solid sample. The result showed that mist eliminator operated well, which met the performance guarantee value. But the total amount of desulfurization slurry in flue gas and the sulfate concentration in liquid condensate discharge from the wet duct/stack increased. The liquid condensate accumulated in the wet duct/stack led to liquid re-entrainment. In conclusion, the rainout in this power plant was caused by the short of wet ductwork or liquid discharge system, the droplets caused by re-entrainment carried by the saturated gas released from the stack. The main undissolved components of the rainout were composite carbonate and aluminosilicate. Although ash concentration in this WFGD met the regulation criteria, source apportionment analysis showed that fly ash contributed to rainout was accounted for 60%. This percentage value was same as the data of solid particles in the condensate. It is important to optimize the wet ductwork, wet stack liner, liquid collectors and drainage. Avoiding the accumulation from saturated vapor thermal condensation is an effective way to solve the wet stack rainout.

IET exhaust gas stack. Section, west elevation, foundation plan, access ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

IET exhaust gas stack. Section, west elevation, foundation plan, access ladder, airplane warning light. Ralph M. Parsons 902-5-ANP-712-S 433. Date: May 1954. Approved by INEEL Classification Office for public release. INEEL index code no. 035-0712-60-693-106984 - Idaho National Engineering Laboratory, Test Area North, Scoville, Butte County, ID

30 CFR 250.442 - What are the requirements for a subsea BOP stack?

Code of Federal Regulations, 2010 CFR

2010-07-01

... OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations...) When you drill with a subsea BOP stack, you must install the BOP system before drilling below surface casing. The District Manager may require you to install a subsea BOP system before drilling below the...

Control system adds to precipitator efficiency

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gurrole, G.

1978-02-01

An electrostatic precipitator in use at Lion Oil Co., Martinez, Calif., in a fluid catalytic cracking and CO boiler application, was upgraded by mechanical sectionalization of the gas passage and a new electronic control system. The electrostatic precipitator is installed upstream of the CO boiler to handle gas flow up to 4.77 ft/sec, and pressure to 4.5 psi. The independent gas chambers in the electrostatic precipitator were divided by installing gas-tight partition walls to form a total of four electrostatic fields. The precipitator was also equipped with adjustable inlet gas flow-control baffles for even gas distribution. Rows of grounded collectingmore » electrodes are parallel with the flow of gas. The emitting electrode system, powered by separate high-energy transformers for each collecting field, uses silicon-controlled rectifiers and analog electronic networks for rapid response to changing gas and dust conditions. Regulatory requirements call for efficient collection of catalyst fines with no more than 40 lb/hr escaping through the boiler stack. Currently, stack losses average about 38 lb/hr. The installation of two additional control systems with transformers and rectifiers should reduce stack losses to 34 lb/hr.« less

Volatile metal species in coal combustion flue gas.

PubMed

Pavageau, Marie-Pierre; Pécheyran, Christophe; Krupp, Eva M; Morin, Anne; Donard, Olivier F X

2002-04-01

Metals are released in effluents of most of combustion processes and are under intensive regulations. To improve our knowledge of combustion process and their resulting emission of metal to the atmosphere, we have developed an approach allowing usto distinguish between gaseous and particulate state of the elements emitted. This study was conducted on the emission of volatile metallic species emitted from a coal combustion plant where low/medium volatile coal (high-grade ash) was burnt. The occurrence of volatile metal species emission was investigated by cryofocusing sampling procedure and detection using low-temperature packed-column gas chromatography coupled with inductively coupled plasma-mass spectrometry as multielement detector (LT-GC/ICP-MS). Samples were collected in the stack through the routine heated sampling line of the plant downstream from the electrostatic precipitator. The gaseous samples were trapped with a cryogenic device and analyzed by LT-GC/ICP-MS. During the combustion process, seven volatile metal species were detected: three for Se, one for Sn, two for Hg, and one for Cu. Thermodynamic calculations and experimental metal species spiking experiments suggest that the following volatile metal species are present in the flue gas during the combustion process: COSe, CSSe, CSe2, SeCl2, Hg0, HgCl2, CuO-CuSO4 or CuSO4 x H2O, and SnO2 or SnCl2. The quantification of volatile species was compared to results traditionally obtained by standardized impinger-based sampling and analysis techniques recommended for flue gas combustion characterization. Results showed that concentrations obtained with the standard impinger approach are at least 10 times higher than obtained with cryogenic sampling, suggesting the trapping microaerosols in the traditional methods. Total metal concentrations in particles are also reported and discussed.

Hydrogen Fueled Hybrid Solid Oxide Fuel Cell-Gas Turbine (SOFC-GT) System for Long-Haul Rail Application

NASA Astrophysics Data System (ADS)

Chow, Justin Jeff

Freight movement of goods is the artery for America's economic health. Long-haul rail is the premier mode of transport on a ton-mile basis. Concerns regarding greenhouse gas and criteria pollutant emissions, however, have motivated the creation of annually increasing locomotive emissions standards. Health issues from diesel particulate matter, especially near rail yards, have also been on the rise. These factors and the potential to raise conventional diesel-electric locomotive performance warrants the investigation of using future fuels in a more efficient system for locomotive application. This research evaluates the dynamic performance of a Solid Oxide Fuel Cell-Gas Turbine (SOFC-GT) Hybrid system operating on hydrogen fuel to power a locomotive over a rail path starting from the Port of Los Angeles and ending in the City of Barstow. Physical constraints, representative locomotive operation logic, and basic design are used from a previous feasibility study and simulations are performed in the MATLAB Simulink environment. In-house controls are adapted to and expanded upon. Results indicate high fuel-to-electricity efficiencies of at least 54% compared to a conventional diesel-electric locomotive efficiency of 35%. Incorporation of properly calibrated feedback and feed-forward controls enables substantial load following of difficult transients that result from train kinematics while maintaining turbomachinery operating requirements and suppressing thermal stresses in the fuel cell stack. The power split between the SOFC and gas turbine is deduced to be a deterministic factor in the balance between capital and operational costs. Using hydrogen results in no emissions if renewable and offers a potential of 24.2% fuel energy savings for the rail industry.

Improve Your Boiler's Combustion Efficiency: Office of Industrial Technologies (OIT) Steam Energy Tips No.4

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

2002-03-01

Operating your boiler with an optimum amount of excess air will minimize heat loss up the stack and improve combustion efficiency. Combustion efficiency is a measure of how effectively the heat content of a fuel is transferred into usable heat. The stack temperature and flue gas oxygen (or carbon dioxide) concentrations are primary indicators of combustion efficiency. Given complete mixing, a precise or stoichiometric amount of air is required to completely react with a given quantity of fuel. In practice, combustion conditions are never ideal, and additional or ''excess'' air must be supplied to completely burn the fuel. The correctmore » amount of excess air is determined from analyzing flue gas oxygen or carbon dioxide concentrations. Inadequate excess air results in unburned combustibles (fuel, soot, smoke, and carbon monoxide) while too much results in heat lost due to the increased flue gas flow--thus lowering the overall boiler fuel-to-steam efficiency. The table relates stack readings to boiler performance. On well-designed natural gas-fired systems, an excess air level of 10% is attainable. An often stated rule of thumb is that boiler efficiency can be increased by 1% for each 15% reduction in excess air or 40 F reduction in stack gas temperature.« less

The thermal stability of Pt/epitaxial Gd2O3/Si stacks and its dependence on heat-treatment ambient

NASA Astrophysics Data System (ADS)

Lipp, E.; Osten, H. J.; Eizenberg, M.

2009-12-01

The stability of Pt/epitaxial Gd2O3/Si stacks is studied by monitoring the chemical and electrical properties following heat treatments in forming gas and in vacuum at temperatures between 400 and 650 °C. Our results show that stack instability is realized via diffusion of Gd through the Pt grain boundaries, which was observed after forming-gas annealing at 550 °C for 30 min. The Gd diffusion kinetics in forming gas is studied by secondary ion mass spectrometry analysis, showing that the diffusion process occurs according to C-type kinetics with an activation energy of 0.73±0.04 eV. Following vacuum heat treatments at 600 °C for 30 min, Si outdiffusion is observed, in addition to Gd outdiffusion. Si outdiffusion results in the formation of PtSi clusters on the metal surface following vacuum annealing at 650 °C. In contrast, in the case of forming-gas treatments, Si diffusion and silicide formation were detected only after annealing at 700 °C. The better stability of Pt/Gd2O3/Si stacks in forming gas is correlated with the content of oxygen in the Pt layer during the treatment.

Gas sensor

DOEpatents

Schmid, Andreas K.; Mascaraque, Arantzazu; Santos, Benito; de la Figuera, Juan

2014-09-09

A gas sensor is described which incorporates a sensor stack comprising a first film layer of a ferromagnetic material, a spacer layer, and a second film layer of the ferromagnetic material. The first film layer is fabricated so that it exhibits a dependence of its magnetic anisotropy direction on the presence of a gas, That is, the orientation of the easy axis of magnetization will flip from out-of-plane to in-plane when the gas to be detected is present in sufficient concentration. By monitoring the change in resistance of the sensor stack when the orientation of the first layer's magnetization changes, and correlating that change with temperature one can determine both the identity and relative concentration of the detected gas. In one embodiment the stack sensor comprises a top ferromagnetic layer two mono layers thick of cobalt deposited upon a spacer layer of ruthenium, which in turn has a second layer of cobalt disposed on its other side, this second cobalt layer in contact with a programmable heater chip.

Evaluation of volatile organic emissions from hazardous waste incinerators.

PubMed Central

Sedman, R M; Esparza, J R

1991-01-01

Conventional methods of risk assessment typically employed to evaluate the impact of hazardous waste incinerators on public health must rely on somewhat speculative emissions estimates or on complicated and expensive sampling and analytical methods. The limited amount of toxicological information concerning many of the compounds detected in stack emissions also complicates the evaluation of the public health impacts of these facilities. An alternative approach aimed at evaluating the public health impacts associated with volatile organic stack emissions is presented that relies on a screening criterion to evaluate total stack hydrocarbon emissions. If the concentration of hydrocarbons in ambient air is below the screening criterion, volatile emissions from the incinerator are judged not to pose a significant threat to public health. Both the screening criterion and a conventional method of risk assessment were employed to evaluate the emissions from 20 incinerators. Use of the screening criterion always yielded a substantially greater estimate of risk than that derived by the conventional method. Since the use of the screening criterion always yielded estimates of risk that were greater than that determined by conventional methods and measuring total hydrocarbon emissions is a relatively simple analytical procedure, the use of the screening criterion would appear to facilitate the evaluation of operating hazardous waste incinerators. PMID:1954928

Development of on-site PAFC stacks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hotta, K.; Matsumoto, Y.; Horiuchi, H.

1996-12-31

PAFC (Phosphoric Acid Fuel Cell) has been researched for commercial use and demonstration plants have been installed in various sites. However, PAFC don`t have a enough stability yet, so more research and development must be required in the future. Especially, cell stack needs a proper state of three phases (liquid, gas and solid) interface. It is very difficult technology to keep this condition for a long time. In the small size cell with the electrode area of 100 cm{sup 2}, gas flow and temperature distributions show uniformity. But in the large size cell with the electrode area of 4000 cm{supmore » 2}, the temperature distributions show non-uniformity. These distributions would cause to be shorten the cell life. Because these distributions make hot-spot and gas poverty in limited parts. So we inserted thermocouples in short-stack for measuring three-dimensional temperature distributions and observed effects of current density and gas utilization on temperature.« less

Effect of shroud geometry on the effectiveness of a short mixing stack gas eductor model

NASA Astrophysics Data System (ADS)

Kavalis, A. E.

1983-06-01

An existing apparatus for testing models of gas eductor systems using high temperature primary flow was modified to provide improved control and performance over a wide range of gas temperature and flow rates. Secondary flow pumping, temperature and pressure data were recorded for two gas eductor system models. The first, previously tested under hot flow conditions, consists of a primary plate with four tilted-angled nozzles and a slotted, shrouded mixing stack with two diffuser rings (overall L/D = 1.5). A portable pyrometer with a surface probe was used for the second model in order to identify any hot spots at the external surface of the mixing stack, shroud and diffuser rings. The second model is shown to have almost the same mixing and pumping performance with the first one but to exhibit much lower shroud and diffuser surface temperatures.

Effect on combined cycle efficiency of stack gas temperature constraints to avoid acid corrosion

NASA Technical Reports Server (NTRS)

Nainiger, J. J.

1980-01-01

To avoid condensation of sulfuric acid in the gas turbine exhaust when burning fuel oils contaning sulfur, the exhaust stack temperature and cold-end heat exchanger surfaces must be kept above the condensation temperature. Raising the exhaust stack temperature, however, results in lower combined cycle efficiency compared to that achievable by a combined cycle burning a sulfur-free fuel. The maximum difference in efficiency between the use of sulfur-free and fuels containing 0.8 percent sulfur is found to be less than one percentage point. The effect of using a ceramic thermal barrier coating (TBC) and a fuel containing sulfur is also evaluated. The combined-cycle efficiency gain using a TBC with a fuel containing sulfur compared to a sulfur-free fuel without TBC is 0.6 to 1.0 percentage points with air-cooled gas turbines and 1.6 to 1.8 percentage points with water-cooled gas turbines.

Estimation and characterization of PCDD/Fs, dl-PCBs, PCNs, HxCBz and PeCBz emissions from magnesium metallurgy facilities in China.

PubMed

Nie, Zhiqiang; Zheng, Minghui; Liu, Wenbin; Zhang, Bing; Liu, Guorui; Su, Guijin; Lv, Pu; Xiao, Ke

2011-12-01

Magnesium production is considered to be one potential source of unintentional persistent organic pollutants (unintentional POPs). However, studies on the emissions of unintentional POPs from magnesium metallurgy are still lacking. Emissions of unintentional POPs, such as polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs), dioxin-like polychlorinated biphenyls (dl-PCBs), polychlorinated naphthalenes (PCNs), hexachlorobenzene (HxCBz) and pentachlorobenzene (PeCBz) are covered under the Stockholm Convention. In this study, these emissions were investigated through a magnesium smelting process. Stack gas and fly ash samples from a typical magnesium plant in China were collected and analyzed to estimate the emissions of unintentional POPs from magnesium metallurgy. Emissions factors of 412 ng TEQ t(-1) for PCDD/Fs, 18.6 ng TEQ t(-1) for dl-PCBs, 3329 μg t(-1) for PCNs, 820 μg t(-1) for HxCBz, and 1326 μg t(-1) for PeCBz were obtained in 2009. Annual emissions from magnesium metallurgy in China were estimated to be 0.46 g WHO-TEQ for PCDD/Fs and dl-PCBs, 1651 g for PCNs, 403 g for HxCBz and 653 g for PeCBz, respectively. Copyright © 2011 Elsevier Ltd. All rights reserved.

Hanford Site radionuclide national emission standards for hazardous ari pollutants registered and and unregistered stack (powered exhaust) source assessment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Davis, W.E.

1995-12-01

On February 3, 1993, US DOE Richland Operations Office received a Compliance Order and Information Request from the Director of the Air and Toxics Div. of US EPA, Region X. The compliance order requires the Richland Operations Office to evaluate all radionuclide emission points at the Hanford site to determine which are subject to the continuous emission measurement requirements in Title 40, Code of Federal Regulations (CFR), Part 61, Subpart H, and to continuously measure radionuclide emissions in accordance with 40 CFR 61.93. The Information Request required The provision of a written compliance plan to meet the requirements of themore » compliance order. A compliance plan was submitted to EPA, Region X, on April 30, 1993. It set as one of the milestones, the complete assessment of the Hanford Site 84 stacks registered with the Washington State Department of Health, by December 17, 1993. This milestone was accomplished. The compliance plan also called for reaching a Federal Facility Compliance Agreement; this was reached on February 7, 1994, between DOE Richland Operations and EPA, Region X. The milestone to assess the unregistered stacks (powered exhaust) by August 31, 1994, was met. This update presents assessments for 72 registered and 22 unregistered stacks with potential emissions > 0.1 mrem/yr.« less

Research of carbon composite material for nonlinear finite element method

NASA Astrophysics Data System (ADS)

Kim, Jung Ho; Garg, Mohit; Kim, Ji Hoon

2012-04-01

Works on the absorption of collision energy in the structural members are carried out widely with various material and cross-sections. And, with ever increasing safety concerns, they are presently applied in various fields including railroad trains, air crafts and automobiles. In addition to this, problem of lighting structural members became important subject by control of exhaust gas emission, fuel economy and energy efficiency. CFRP(Carbon Fiber Reinforced Plastics) usually is applying the two primary structural members because of different result each design parameter as like stacking thickness, stacking angle, moisture absorption ect. We have to secure the data for applying primary structural members. But it always happens to test design parameters each for securing the data. So, it has much more money and time. We can reduce the money and the time, if can ensure the CFRP material properties each design parameters. In this study, we experiment the coupon test each tension, compression and shear using CFRP prepreg sheet and simulate non-linear analyze at the sources - test result, Caron longitudinal modulus and matrix poisson's ratio using GENOAMQC is specialized at Composite analysis. And then we predict the result that specimen manufacture changing stacking angle and experiment in such a way of test method using GENOA-MCQ.

Construction of energy transfer pathways self-assembled from DNA-templated stacks of anthracene.

PubMed

Iwaura, Rika; Yui, Hiroharu; Someya, Yuu; Ohnishi-Kameyama, Mayumi

2014-01-05

We describe optical properties of anthracene stacks formed from single-component self-assembly of thymidylic acid-appended anthracene 2,6-bis[5-(3'-thymidylic acid)pentyloxy] anthracene (TACT) and the binary self-assembly of TACT and complementary 20-meric oligoadenylic acid (TACT/dA20) in an aqueous buffer. UV-Vis and emission spectra for the single-component self-assembly of TACT and the binary self-assembly of TACT/dA20 were very consistent with stacked acene moieties in both self-assemblies. Interestingly, time-resolved fluorescence spectra from anthracene stacks exhibited very different features of the single-component and binary self-assemblies. In the single-component self-assembly of TACT, a dynamic Stokes shift (DSS) and relatively short fluorescence lifetime (τ=0.35ns) observed at around 450nm suggested that the anthracene moieties were flexible. Moreover, a broad emission at 530nm suggested the formation of an excited dimer (excimer). In the binary self-assembly of TACT/dA20, we detected a broad, red-shifted emission component at 534nm with a lifetime (τ=0.4ns) shorter than that observed in the TACT single-component self-assembly. Combining these results with the emission spectrum of the binary self-assembly of TACT/5'-HEX dA20, we concluded that the energy transfer pathway was constructed by columnar anthracene stacks formed from the DNA-templated self-assembly of TACT. Copyright © 2013 Elsevier B.V. All rights reserved.

X-ray Emission Line Spectroscopy of Nearby Galaxies

NASA Astrophysics Data System (ADS)

Wang, Daniel

What are the origins of the diffuse soft X-ray emission from non-AGN galaxies? Preliminary analysis of XMM-Newton RGS spectra shows that a substantial fraction of the emission cannot arise from optically-thin thermal plasma, as commonly assumed, and may originate in charge exchange at the interface with neutral gas. We request the support for a comprehensive observing, data analysis, and modeling program to spectroscopically determine the origins of the emission. First, we will use our scheduled XMM-Newton AO-10 368 ks observations of the nearest compact elliptical galaxy M32 to obtain the first spectroscopic calibration of the cumulative soft X-ray emission from the old stellar population and will develop a spectral model for the charge exchange, as well as analysis tools to measure the spatial and kinematic properties of the X-ray line- emitting plasma. Second, we will characterize the truly diffuse emission from the hot plasma and/or its interplay with the neutral gas in a sample of galactic spheroids and active star forming/starburst regions in nearby galaxies observed by XMM-Newton. In particular, we will map out the spatial distributions of key emission lines and measure (or tightly constrain) the kinematics of hot plasma outflows for a few X-ray-emitting regions with high-quality RGS data. For galaxies with insufficient counting statistics in individual emission lines, we will conduct a spectral stacking analysis to constrain the average properties of the X-ray-emitting plasma. We will use the results of these X-ray spectroscopic analyses, together with complementary X-ray CCD imaging/spectral data and observations in other wavelength bands, to test the models of the emission. In addition to the charge exchange, alternative scenarios such as resonance scattering and relic AGN photo-ionization will also be examined for suitable regions. These studies are important to the understanding of the relationship between the diffuse soft X-ray emission and various high-energy feedback processes of the galaxies.

Properties of Repetitive Long-Period Seismicity at Villarrica Volcano, Chile

NASA Astrophysics Data System (ADS)

Richardson, J.; Waite, G. P.; Palma, J.; Johnson, J. B.

2011-12-01

Villarrica Volcano, Chile hosts a persistent lava lake and is characterized by degassing and long-period seismicity. In order to better understand the relationship between outgassing and seismicity, we recorded broadband seismic and acoustic data along with high-rate SO2 emission data. We used both a densely-spaced linear array deployed on the northern flank of Villarrica, during the austral summer of 2011, and a wider aperture array of stations distributed around the volcano that was active in the austral summer of 2010. Both deployments consisted of three-component broadband stations and were augmented with broadband infrasound sensors. Of particular interests are repetitive, ~1 Hz seismic and coincident infrasound signals that occurred approximately every 2 minutes. Because these events are typically very low amplitude, we used a matched filter approach to identify them. We windowed several high-amplitude records of these events from broadband seismic stations near the vent. The record section of each event served as a template to compare with the entire dataset by cross-correlation. This approach identified ~20,000 nearly identical events during the ~7 day deployment of the linear array, which were otherwise difficult to identify in the raw records. Assuming that all of the events that we identified have identical source mechanisms and depths, we stack the large suite of events to produce low-noise records and particle motions at receivers farther than 5 km from the vent. We find that the records from stations near the edifice are dominated by tangential particle motion, suggesting the influence of near-field components. Correlation of these data with broadband acoustic data collected at the summit suggest that these repeatable seismic processes are linked to acoustic emissions, probably due to gas bubbles bursting at the magma free surface, as no eruptive products besides gas were being emitted by the volcano during the instrument deployment. The acoustic signals affiliated with the repetitive seismic signals do not seem directly related to the continuous, well-correlated acoustic tremor observed both at the vent and at roughly 6 km away from small-aperture acoustic arrays (also reported by other groups in 2009, 2010). We also correlate the acoustic and repetitive seismic signals with high time resolution (~1 Hz sampling rate), sulfur dioxide emissions measured with an ultraviolet camera. Because a subset of stations operated during both 2010 and 2011, we could tie events from both deployments to generate a single stacked event at all 17 stations. We will present results of finite-difference modeling of this event stack using a simple homogeneous velocity structure.

The Diversity of Diffuse Ly α Nebulae around Star-forming Galaxies at High Redshift

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xue, Rui; Lee, Kyoung-Soo; Dey, Arjun

2017-03-10

We report the detection of diffuse Ly α emission, or Ly α halos (LAHs), around star-forming galaxies at z ≈ 3.78 and 2.66 in the NOAO Deep Wide-Field Survey Boötes field. Our samples consist of a total of ∼1400 galaxies, within two separate regions containing spectroscopically confirmed galaxy overdensities. They provide a unique opportunity to investigate how the LAH characteristics vary with host galaxy large-scale environment and physical properties. We stack Ly α images of different samples defined by these properties and measure their median LAH sizes by decomposing the stacked Ly α radial profile into a compact galaxy-like andmore » an extended halo-like component. We find that the exponential scale-length of LAHs depends on UV continuum and Ly α luminosities, but not on Ly α equivalent widths or galaxy overdensity parameters. The full samples, which are dominated by low UV-continuum luminosity Ly α emitters ( M {sub UV} ≳ −21), exhibit LAH sizes of 5–6 kpc. However, the most UV- or Ly α- luminous galaxies have more extended halos with scale-lengths of 7–9 kpc. The stacked Ly α radial profiles decline more steeply than recent theoretical predictions that include the contributions from gravitational cooling of infalling gas and from low-level star formation in satellites. However, the LAH extent matches what one would expect for photons produced in the galaxy and then resonantly scattered by gas in an outflowing envelope. The observed trends of LAH sizes with host galaxy properties suggest that the physical conditions of the circumgalactic medium (covering fraction, H i column density, and outflow velocity) change with halo mass and/or star formation rates.« less

The Diversity of Diffuse Lyα Nebulae around Star-forming Galaxies at High Redshift

NASA Astrophysics Data System (ADS)

Xue, Rui; Lee, Kyoung-Soo; Dey, Arjun; Reddy, Naveen; Hong, Sungryong; Prescott, Moire K. M.; Inami, Hanae; Jannuzi, Buell T.; Gonzalez, Anthony H.

2017-03-01

We report the detection of diffuse Lyα emission, or Lyα halos (LAHs), around star-forming galaxies at z ≈ 3.78 and 2.66 in the NOAO Deep Wide-Field Survey Boötes field. Our samples consist of a total of ˜1400 galaxies, within two separate regions containing spectroscopically confirmed galaxy overdensities. They provide a unique opportunity to investigate how the LAH characteristics vary with host galaxy large-scale environment and physical properties. We stack Lyα images of different samples defined by these properties and measure their median LAH sizes by decomposing the stacked Lyα radial profile into a compact galaxy-like and an extended halo-like component. We find that the exponential scale-length of LAHs depends on UV continuum and Lyα luminosities, but not on Lyα equivalent widths or galaxy overdensity parameters. The full samples, which are dominated by low UV-continuum luminosity Lyα emitters (M UV ≳ -21), exhibit LAH sizes of 5-6 kpc. However, the most UV- or Lyα-luminous galaxies have more extended halos with scale-lengths of 7-9 kpc. The stacked Lyα radial profiles decline more steeply than recent theoretical predictions that include the contributions from gravitational cooling of infalling gas and from low-level star formation in satellites. However, the LAH extent matches what one would expect for photons produced in the galaxy and then resonantly scattered by gas in an outflowing envelope. The observed trends of LAH sizes with host galaxy properties suggest that the physical conditions of the circumgalactic medium (covering fraction, H I column density, and outflow velocity) change with halo mass and/or star formation rates.

76. General view looking east showing Rust Co. boiler stacks ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

76. General view looking east showing Rust Co. boiler stacks at left, Babcock & Wilcox type boiler stacks at right, Dovel horizontal gas washer in foreground, and No. 1 Furnace in distance. - Sloss-Sheffield Steel & Iron, First Avenue North Viaduct at Thirty-second Street, Birmingham, Jefferson County, AL

30 CFR 250.441 - What are the requirements for a surface BOP stack?

Code of Federal Regulations, 2010 CFR

2010-07-01

... OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations...? (a) When you drill with a surface BOP stack, you must install the BOP system before drilling below... with blind-shear rams. The blind-shear rams must be capable of shearing the drill pipe that is in the...

30 CFR 250.416 - What must I include in the diverter and BOP descriptions?

Code of Federal Regulations, 2010 CFR

2010-07-01

... OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Applying for A Permit to Drill § 250.416 What must I include in the diverter and BOP descriptions? You must... rams installed in the BOP stack (both surface and subsea stacks) are capable of shearing the drill pipe...

UTC Power/Delphi SECA CBS Final Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gorman, Michael; Kerr, Rich

2013-04-04

The subject report summarizes the results of solid oxide fuel cell development conducted by UTC Power in conjunction with Delphi Automotive Systems under a cost-share program with from October 2008 through March of 2013. Over that period Delphi Automotive Systems developed a nearly four times larger area solid oxide fuel cell stack capable of operating on pre-reformed natural gas and simulated coal gas with durability demonstrated to 5,000 hours and projected to exceed 10,000 hours. The new stack design was scaled to 40-cell stacks with power output in excess of 6.25kW. Delphi also made significant strides in improving the manufacturability,more » yield and production cost of these solid oxide fuel cells over the course of the program. Concurrently, UTC Power developed a conceptual design for a 120 MW Integrated Gasification Fuel Cell (IGFC) operating on coal syngas with as high as 57% Higher Heating Value (HHV) efficiency as a measure of the feasibility of the technology. Subsequently a 400 kW on-site system preliminary design with 55% Lower Heating Value (LHV) efficiency operating on natural gas was down-selected from eighteen candidate designs. That design was used as the basis for a 25kW breadboard power plant incorporating four Delphi cell stacks that was tested on natural gas before the program was discontinued due to the sale of UTC Power in early 2013. Though the program was cut short of the endurance target of 3,000 hours, many aspects of the technology were proven including: large-area, repeatable cell manufacture, cell stack operation on simulated coal gas and natural gas and integrated power plant operation on natural gas. The potential of the technology for high efficiency stationary electric power generation is clear. Acceptable production costs, durability, and reliability in real world environments are the remaining challenges to commercialization.« less

Stacked white OLED having separate red, green and blue sub-elements

DOEpatents

Forrest, Stephen; Qi, Xiangfei; Slootsky, Michael

2014-07-01

The present invention relates to efficient organic light emitting devices (OLEDs). The devices employ three emissive sub-elements, typically emitting red, green and blue, to sufficiently cover the visible spectrum. Thus, the devices may be white-emitting OLEDs, or WOLEDs. Each sub-element comprises at least one organic layer which is an emissive layer--i.e., the layer is capable of emitting light when a voltage is applied across the stacked device. The sub-elements are vertically stacked and are separated by charge generating layers. The charge-generating layers are layers that inject charge carriers into the adjacent layer(s) but do not have a direct external connection.

Field pilot study on emissions, formations and distributions of PCDD/Fs from cement kiln co-processing fly ash from municipal solid waste incinerations.

PubMed

Liu, Guorui; Zhan, Jiayu; Zheng, Minghui; Li, Li; Li, Chunping; Jiang, Xiaoxu; Wang, Mei; Zhao, Yuyang; Jin, Rong

2015-12-15

A pilot study was performed to evaluate formation, distribution and emission of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) from cement kilns that co-process fly ash from municipal solid waste incineration (MSWI). Stack gas and particulate samples from multiple stages in the process were collected and analyzed for PCDD/Fs. Stack emissions of PCDD/Fs were below the European Union limit for cement kilns (0.1 ng TEQ m(-3)). PCDD/F concentrations in particulates from the cyclone preheater outlet, suspension preheater boiler, humidifier tower, and back-end bag filter were much higher than in other samples, which suggests that these areas are the major sites of PCDD/F formation. Comparison of PCDD/F homolog and congener profiles from different stages suggested that tetra- and penta-chlorinated furans were mainly formed during cement kiln co-processing of MSWI fly ash. Three lower chlorinated furan congeners, including 2,3,7,8-tetrachlorodibenzofuran, 1,2,3,7,8-pentachlorodibenzo-p-dioxin and 2,3,4,7,8-pentachlorodibenzofuran, were identified as dominant contributors to the toxic equivalents (TEQ) of the PCDD/Fs. The concentration of PCDD/Fs in particulates was correlated with chloride content, which is consistent with its positive effect on PCDD/F formation. This could be mitigated by pretreating the feedstock to remove chloride and metals. Mass balance indicated that cement kilns eliminated about 94% of the PCDD/F TEQ input from the feedstock. Copyright © 2015 Elsevier B.V. All rights reserved.

Interlayer orientation-dependent light absorption and emission in monolayer semiconductor stacks

PubMed Central

Heo, Hoseok; Sung, Ji Ho; Cha, Soonyoung; Jang, Bo-Gyu; Kim, Joo-Youn; Jin, Gangtae; Lee, Donghun; Ahn, Ji-Hoon; Lee, Myoung-Jae; Shim, Ji Hoon; Choi, Hyunyong; Jo, Moon-Ho

2015-01-01

Two-dimensional stacks of dissimilar hexagonal monolayers exhibit unusual electronic, photonic and photovoltaic responses that arise from substantial interlayer excitations. Interband excitation phenomena in individual hexagonal monolayer occur in states at band edges (valleys) in the hexagonal momentum space; therefore, low-energy interlayer excitation in the hexagonal monolayer stacks can be directed by the two-dimensional rotational degree of each monolayer crystal. However, this rotation-dependent excitation is largely unknown, due to lack in control over the relative monolayer rotations, thereby leading to momentum-mismatched interlayer excitations. Here, we report that light absorption and emission in MoS2/WS2 monolayer stacks can be tunable from indirect- to direct-gap transitions in both spectral and dynamic characteristics, when the constituent monolayer crystals are coherently stacked without in-plane rotation misfit. Our study suggests that the interlayer rotational attributes determine tunable interlayer excitation as a new set of basis for investigating optical phenomena in a two-dimensional hexagonal monolayer system. PMID:26099952

Cell module and fuel conditioner development

NASA Technical Reports Server (NTRS)

Hoover, D. Q., Jr.

1982-01-01

The phosphoric acid fuel cell module (stack) development which culminated in an 80 cell air-cooled stack with separated gas cooling and treed cooling plates is described. The performance of the 80 cell stack was approx. 100 mV per cell higher than that attained during phase 1. The components and materials performed stably for over 8000 hours in a 5 cell stack. The conceptual design of a fuel conditioning system is described.

Comparison of the Current Center of Site Annual Neshap Dose Modeling at the Savannah River Site with Other Assessment Methods.

PubMed

Minter, Kelsey M; Jannik, G Timothy; Stagich, Brooke H; Dixon, Kenneth L; Newton, Joseph R

2018-04-01

The U.S. Environmental Protection Agency (EPA) requires the use of the model CAP88 to estimate the total effective dose (TED) to an offsite maximally exposed individual (MEI) for demonstrating compliance with 40 CFR 61, Subpart H: The National Emission Standards for Hazardous Air Pollutants (NESHAP) regulations. For NESHAP compliance at the Savannah River Site (SRS), the EPA, the U.S. Department of Energy (DOE), South Carolina's Department of Health and Environmental Control, and SRS approved a dose assessment method in 1991 that models all radiological emissions as if originating from a generalized center of site (COS) location at two allowable stack heights (0 m and 61 m). However, due to changes in SRS missions, radiological emissions are no longer evenly distributed about the COS. An area-specific simulation of the 2015 SRS radiological airborne emissions was conducted to compare to the current COS method. The results produced a slightly higher dose estimate (2.97 × 10 mSv vs. 2.22 × 10 mSv), marginally changed the overall MEI location, and noted that H-Area tritium emissions dominated the dose. Thus, an H-Area dose model was executed as a potential simplification of the area-specific simulation by adopting the COS methodology and modeling all site emissions from a single location in H-Area using six stack heights that reference stacks specific to the tritium production facilities within H-Area. This "H-Area Tritium Stacks" method produced a small increase in TED estimates (3.03 × 10 mSv vs. 2.97 × 10 mSv) when compared to the area-specific simulation. This suggests that the current COS method is still appropriate for demonstrating compliance with NESHAP regulations but that changing to the H-Area Tritium Stacks assessment method may now be a more appropriate representation of operations at SRS.

Primary particulate matter from ocean-going engines in the Southern California Air Basin.

PubMed

Agrawal, Harshit; Eden, Rudy; Zhang, Xinqiu; Fine, Philip M; Katzenstein, Aaron; Miller, J Wayne; Ospital, Jean; Teffera, Solomon; Cocker, David R

2009-07-15

The impact of primary fine particulate matter (PM2.5) from ship emissions within the Southern California Air Basin is quantified by comparing in-stack vanadium (V) and nickel (Ni) measurements from in-use ocean-going vessels (OGVs) with ambient measurements made at 10 monitoring stations throughout Southern California. V and Ni are demonstrated as robust markers for the combustion of heavy fuel oil in OGVs, and ambient measurements of fine particulate V and Ni within Southern California are shown to decrease inversely with increased distance from the ports of Los Angeles and Long Beach (ports). High levels of V and Ni were observed from in-stack emission measurements conducted on the propulsion engines of two different in-use OGVs. The in-stack V and Ni emission rates (g/h) normalized by the V and Ni contents in the fuel tested correlates with the stack total PM emission rates (g/h). The normalized emission rates are used to estimate the primary PM2.5 contributions from OGVs at 10 monitoring locations within Southern California. Primary PM2.5 contributions from OGVs were found to range from 8.8% of the total PM2.5 at the monitoring location closest to the port (West Long Beach) to 1.4% of the total PM2.5 at the monitoring location 80 km inland (Rubidoux). The calculated OGV contributions to ambient PM2.5 measurements at the 10 monitoring sites agree well with estimates developed using an emission inventory based regional model. Results of this analysis will be useful in determining the impacts of primary particulate emissions from OGVs upon worldwide communities downwind of port operations.

A high-dispersion molecular gas component in nearby galaxies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Caldú-Primo, Anahi; Walter, Fabian; Sandstrom, Karin

2013-12-01

We present a comprehensive study of the velocity dispersion of the atomic (H I) and molecular (H{sub 2}) gas components in the disks (R ≲ R {sub 25}) of a sample of 12 nearby spiral galaxies with moderate inclinations. Our analysis is based on sensitive high-resolution data from the THINGS (atomic gas) and HERACLES (molecular gas) surveys. To obtain reliable measurements of the velocity dispersion, we stack regions several kiloparsecs in size, after accounting for intrinsic velocity shifts due to galactic rotation and large-scale motions. We stack using various parameters: the galactocentric distance, star formation rate surface density, H Imore » surface density, H{sub 2} surface density, and total gas surface density. We fit single Gaussian components to the stacked spectra and measure median velocity dispersions for H I of 11.9 ± 3.1 km s{sup –1} and for CO of 12.0 ± 3.9 km s{sup –1}. The CO velocity dispersions are thus, surprisingly, very similar to the corresponding ones of H I, with an average ratio of σ{sub HI}/σ{sub CO}= 1.0 ± 0.2 irrespective of the stacking parameter. The measured CO velocity dispersions are significantly higher (factor of ∼2) than the traditional picture of a cold molecular gas disk associated with star formation. The high dispersion implies an additional thick molecular gas disk (possibly as thick as the H I disk). Our finding is in agreement with recent sensitive measurements in individual edge-on and face-on galaxies and points toward the general existence of a thick disk of molecular gas, in addition to the well-known thin disk in nearby spiral galaxies.« less

The Development and Application of Spatiotemporal Metrics for the Characterization of Point Source FFCO2 Emissions and Dispersion

NASA Astrophysics Data System (ADS)

Roten, D.; Hogue, S.; Spell, P.; Marland, E.; Marland, G.

2017-12-01

There is an increasing role for high resolution, CO2 emissions inventories across multiple arenas. The breadth of the applicability of high-resolution data is apparent from their use in atmospheric CO2 modeling, their potential for validation of space-based atmospheric CO2 remote-sensing, and the development of climate change policy. This work focuses on increasing our understanding of the uncertainty in these inventories and the implications on their downstream use. The industrial point sources of emissions (power generating stations, cement manufacturing plants, paper mills, etc.) used in the creation of these inventories often have robust emissions characteristics, beyond just their geographic location. Physical parameters of the emission sources such as number of exhaust stacks, stack heights, stack diameters, exhaust temperatures, and exhaust velocities, as well as temporal variability and climatic influences can be important in characterizing emissions. Emissions from large point sources can behave much differently than emissions from areal sources such as automobiles. For many applications geographic location is not an adequate characterization of emissions. This work demonstrates the sensitivities of atmospheric models to the physical parameters of large point sources and provides a methodology for quantifying parameter impacts at multiple locations across the United States. The sensitivities highlight the importance of location and timing and help to highlight potential aspects that can guide efforts to reduce uncertainty in emissions inventories and increase the utility of the models.

Weak Hard X-Ray Emission from Two Broad Absorption Line Quasars Observed with NuStar: Compton-Thick Absorption or Intrinsic X-Ray Weakness?

NASA Technical Reports Server (NTRS)

Luo, B.; Brandt, W. N.; Alexander, D. M.; Harrison, F. A.; Stern, D.; Bauer, F. E.; Boggs, S. E.; Christensen, F. E.; Comastri, A.; Craig, W. W..;

WEAK HARD X-RAY EMISSION FROM TWO BROAD ABSORPTION LINE QUASARS OBSERVED WITH NuSTAR: COMPTON-THICK ABSORPTION OR INTRINSIC X-RAY WEAKNESS?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Luo, B.; Brandt, W. N.; Alexander, D. M.

We present Nuclear Spectroscopic Telescope Array (NuSTAR) hard X-ray observations of two X-ray weak broad absorption line (BAL) quasars, PG 1004+130 (radio loud) and PG 1700+518 (radio quiet). Many BAL quasars appear X-ray weak, probably due to absorption by the shielding gas between the nucleus and the accretion-disk wind. The two targets are among the optically brightest BAL quasars, yet they are known to be significantly X-ray weak at rest-frame 2-10 keV (16-120 times fainter than typical quasars). We would expect to obtain Almost-Equal-To 400-600 hard X-ray ({approx}> 10 keV) photons with NuSTAR, provided that these photons are not significantlymore » absorbed (N{sub H} {approx}< 10{sup 24} cm{sup -2}). However, both BAL quasars are only detected in the softer NuSTAR bands (e.g., 4-20 keV) but not in its harder bands (e.g., 20-30 keV), suggesting that either the shielding gas is highly Compton-thick or the two targets are intrinsically X-ray weak. We constrain the column densities for both to be N{sub H} Almost-Equal-To 7 Multiplication-Sign 10{sup 24} cm{sup -2} if the weak hard X-ray emission is caused by obscuration from the shielding gas. We discuss a few possibilities for how PG 1004+130 could have Compton-thick shielding gas without strong Fe K{alpha} line emission; dilution from jet-linked X-ray emission is one likely explanation. We also discuss the intrinsic X-ray weakness scenario based on a coronal-quenching model relevant to the shielding gas and disk wind of BAL quasars. Motivated by our NuSTAR results, we perform a Chandra stacking analysis with the Large Bright Quasar Survey BAL quasar sample and place statistical constraints upon the fraction of intrinsically X-ray weak BAL quasars; this fraction is likely 17%-40%.« less

Stack gas treatment

DOEpatents

Reeves, Adam A.

1977-04-12

Hot stack gases transfer contained heat to a gravity flow of pebbles treated with a catalyst, cooled stacked gases and a sulfuric acid mist is withdrawn from the unit, and heat picked up by the pebbles is transferred to air for combustion or other process. The sulfuric acid (or sulfur, depending on the catalyst) is withdrawn in a recovery unit.

40 CFR Table 5 to Subpart Ddddd of... - Performance Testing Requirements

Code of Federal Regulations, 2010 CFR

2010-07-01

... 2G in appendix A to part 60 of this chapter. c. Determine oxygen and carbon dioxide concentrations of...) (IBR, see § 63.14(i)). d. Measure the moisture content of the stack gas Method 4 in appendix A to part... stack gas Method 2, 2F, or 2G in appendix A to part 60 of this chapter. c. Determine oxygen and carbon...

Prediction of dioxin/furan incinerator emissions using low-molecular-weight volatile products of incomplete combustion.

PubMed

Lemieux, P M; Lee, C W; Ryan, J V

2000-12-01

Emissions of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDDs/Fs) from incinerators and other stationary combustion sources are of environmental concern because of the toxicity of certain PCDD/F congeners. Measurement of trace levels of PCDDs/Fs in combustor emissions is not a trivial matter. Development of one or more simple, easy-to-measure, reliable indicators of stack PCDD/F concentrations not only would enable incinerator operators to economically optimize system performance with respect to PCDD/F emissions, but could also provide a potential technique for demonstrating compliance status on a more frequent basis. This paper focuses on one approach to empirically estimate PCDD/F emissions using easy-to-measure volatile organic C2 chlorinated alkene precursors coupled with flue gas cleaning parameters. Three data sets from pilot-scale incineration experiments were examined for correlations between C2 chlorinated alkenes and PCDDs/Fs. Each data set contained one or more C2 chloroalkenes that were able to account for a statistically significant fraction of the variance in PCDD/F emissions. Variations in the vinyl chloride concentrations were able to account for the variations in the PCDD/F concentrations strongly in two of the three data sets and weakly in one of the data sets.

Prediction of Dioxin/Furan Incinerator Emissions Using Low-Molecular-Weight Volatile Products of Incomplete Combustion.

PubMed

Lemieux, P M; Lee, C W; Ryan, J V

2000-12-01

Emissions of polychlorinated dibenzo-p-dioxins and poly-chlorinated dibenzofurans (PCDDs/Fs) from incinerators and other stationary combustion sources are of environmental concern because of the toxicity of certain PCDD/F congeners. Measurement of trace levels of PCDDs/Fs in combustor emissions is not a trivial matter. Development of one or more simple, easy-to-measure, reliable indicators of stack PCDD/F concentrations not only would enable incinerator operators to economically optimize system performance with respect to PCDD/F emissions, but could also provide a potential technique for demonstrating compliance status on a more frequent basis. This paper focuses on one approach to empirically estimate PCDD/F emissions using easy-to-measure volatile organic C 2 chlorinated alk-ene precursors coupled with flue gas cleaning parameters. Three data sets from pilot-scale incineration experiments were examined for correlations between C 2 chlorinated alk-enes and PCDDs/Fs. Each data set contained one or more C 2 chloroalkenes that were able to account for a statistically significant fraction of the variance in PCDD/F emissions. Variations in the vinyl chloride concentrations were able to account for the variations in the PCDD/F concentrations strongly in two of the three data sets and weakly in one of the data sets.

Red Geyser: A New Class of Galaxy with Large-scale AGN-driven Winds

NASA Astrophysics Data System (ADS)

Roy, Namrata; Bundy, Kevin; Cheung, Edmond; MaNGA Team

2018-01-01

A new class of quiescent (non-star-forming) galaxies harboring possible AGN-driven winds have been discovered using the spatially resolved optical spectroscopy from the ongoing SDSS-IV MaNGA (Sloan Digital Sky Survey-IV Mapping Nearby Galaxies at Apache Point Observatory) survey. These galaxies named "red geysers" constitute 5%-10% of the local quiescent galaxy population and are characterized by narrow bisymmetric ionized gas emission patterns. These enhanced patterns are seen in equivalent width maps of Hα, [OIII] and other strong emission lines. They are co-aligned with the ionized gas velocity gradients but significantly misaligned with stellar velocity gradients. They also show very high gas velocity dispersions (~200 km/s). Considering these observations in light of models of the gravitational potential, Cheung et al. argued that red geysers host large-scale AGN-driven winds of ionized gas that may play a role in suppressing star formation at late times. In this work, we test the hypothesis that AGN activity is ultimately responsible for the red geyser phenomenon. We compare the nuclear radio activity of the red geysers to a matched control sample of galaxies of similar stellar mass, redshift, rest frame NUV–r color and axis ratio. and additionally, control for the presence of ionized gas. We have used 1.4 GHz radio continuum data from the VLA FIRST Survey to stack the radio flux from the red geyser sample and control sample. We find that the red geysers have a higher average radio flux than the control galaxies at > 3σ significance. Our sample is restricted to rest-frame NUV–r color > 5, thus ruling out possible radio emission due to star formation activity. We conclude that red geysers are associated with more active AGN, supporting a feedback picture in which episodic AGN activity drives large-scale but relatively weak ionized winds in many in many early-type galaxies.

Waste separation: Does it influence municipal waste combustor emissions?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chandler, A.J.; Rigo, H.G.

1996-09-01

It has been suggested that MSW incinerator emissions show significant variations because of the heterogeneous nature of the waste fed to the furnace. This argument has even been used to propose banning certain materials from incinerators. However, data previously reported by the authors suggests that a large portion of the trace metals come from natural sources. Furthermore, full scale incinerator spiking experiments suggest that certain forms of trace metals have minimal effects on stack emissions. Similar studies with chlorinated plastics have failed to identify a significant effect on incinerator dioxin emissions. The implication of segregating the lawn and garden wastemore » and other fines from the furnace feed is explored using data from a 400 tpd mass burn facility equipped with a conditioning tower, dry reactor and fabric filter air pollution control system (APCS) preceded by an NRT separation system. The stack emissions have been tested periodically since commissioning to characterize emissions for various seasons using both processed fuel and raw MSW. Front end processing to remove selected portions of the waste stream based upon size or physical properties, i.e. fines, grass, or ferrous materials, did not result in a statistically significant difference in stack emissions. System operating regime, and in particular those that effect the effective air to cloth ratio in the fabric filter, appear to be the principal influence on emission levels.« less

Twenty years of experience in monitoring 41Ar in a research reactor and decrease of its discharge into the environment.

PubMed

Fukui, M

2004-04-01

The radioactive gas 41Ar has been produced at high concentration by neutron activation near the reactor core in the Kyoto University Research Reactor. A pipe line for an exhaust stream, so-called sweep gas, was fabricated at the construction of the reactor in 1964 in order to exhale 41Ar from the facilities above to the environment. Other exhaust lines with decay tanks were established separately from the sweep line for both the cold neutron source in 1986 and the heavy-water tank in 1996, respectively, because a higher amount of 41Ar was thought to be produced from these facilities due to the improvement. As a result, a slight change in the flow rate of the exhaust was found to have a great deal of influence on both the 41Ar concentration in the reactor room and the rate of emission from the stack. By monitoring the exhaust air from the decay tanks, the mechanism for decreasing the emission was clarified together with identifying an obstacle, i.e., the condensate against the steady state flow, formed in the exhaust pipe. By setting the flow rate suitably in the exhaust line, the rate of 41Ar emission from the biological shielding into both the work place in the reactor room and the environment has been controlled as low as reasonably achievable.

Fuel cell separator with compressible sealing flanges

DOEpatents

Mientek, A.P.

1984-03-30

A separator for separating adjacent fuel cells in a stack of such cells includes a flat, rectangular, gas-impermeable plate disposed between adjacent cells and having two opposite side margins thereof folded back over one side of the plate to form two first seal flanges and having the other side margins thereof folded back over the opposite side of the plate to form two second seal flanges, each of the seal flanges cooperating with the plate to define a channel in which is disposed a resiliently compressible stack of thin metal sheets. The two first seal flanges cooperate with the electrolyte matrix of one of the cells to form a gas-impermeable seal between an electrode of the one cell and one of two reactant gas manifolds. The second seal flanges cooperate with the electrolyte matrix of the other cell for forming a gas-impermeable seal between an electrode of the other cell and the other of the two reactant gas manifolds. The seal flanges cooperate with the associated compressible stacks of sheets for maintaining a spacing between the plate and the electrolyte matrices while accommodating variation of that spacing.

Fuel cell separator with compressible sealing flanges

DOEpatents

Mientek, Anthony P.

1985-04-30

A separator for separating adjacent fuel cells in a stack of such cells includes a flat, rectangular, gas-impermeable plate disposed between adjacent cells and having two opposite side margins thereof folded back over one side of the plate to form two first seal flanges and having the other side margins thereof folded back over the opposite side of the plate to form two second seal flanges, each of the seal flanges cooperating with the plate to define a channel in which is disposed a resiliently compressible stack of thin metal sheets. The two first seal flanges cooperate with the electrolyte matrix of one of the cells to form a gas-impermeable seal between an electrode of the one cell and one of two reactant gas manifolds. The second seal flanges cooperate with the electrolyte matrix of the other cell for forming a gas-impermeable seal between an electrode of the other cell and the other of the two reactant gas manifolds. The seal flanges cooperate with the associated compressible stacks of sheets for maintaining a spacing between the plate and the electrolyte matrices while accommodating variation of that spacing.

Characteristics of dioxin emissions from a Waelz plant with acid and basic kiln mode.

PubMed

Hung, Pao Chen; Chi, Kai Hsien; Chen, Mei Lien; Chang, Moo Been

2012-01-30

The concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were measured in the flue gas of a Waelz plant operated in acid and basic modes, respectively. To abate (PCDD/F) and other pollutants, the plant operates with a post-treatment of flue gases by activated carbon injection and subsequent filtration. Relatively high PCDD/F discharge by fly ashes is found with acid kiln mode of the Waelz process. Therefore, basic kiln mode of the Waelz process is investigated and compared in this plant. With the adsorbent injection rate of 7 kg/h (95 mg/Nm(3)), the PCDD/F concentration in stack gas was measured as 0.123 ng I-TEQ/Nm(3) in the basic operating mode. The added Ca(OH)(2) reacted with metal catalysts and HCl((g)) in the flue gas and thus effectively suppressed the formation of PCDD/Fs. PCDD/F concentrations in fly ashes sampled from the dust settling chamber, cyclone, primary filter and secondary filter in basic kiln mode were significantly lower than that in acid kiln mode. Total PCDD/F emission on the basis of treating one kg of electric arc furnace dust in the basic operation mode was 269 ng I-TEQ/kg EAF-dust treated which was significantly lower than that in acid mode (640 ng I-TEQ/kg EAF-dust treated). Copyright © 2011 Elsevier B.V. All rights reserved.

Emission of Polychlorinated Naphthalenes during Thermal Related Processes

NASA Astrophysics Data System (ADS)

Liu, Guorui; Zheng, Minghui; Du, Bing; Liu, Wenbin; Zhang, Bing; Xiao, Ke

2010-05-01

Due to the structural similarity of polychlorinated naphthalenes (PCNs) to those of dioxins, PCNs exhibit toxicological properties similar to dioxins (Olivero-Verbel et al., 2004). Based on their high toxicity, persistence, bioaccumulation, and long-distance transmission, PCNs were also selected as a candidate POP for the UN-ECE (United Nations Economic Commission for Europe) POP protocol (Lerche et al., 2002). In addition, some studies suggested that PCNs contributed a greater proportion of the dioxin-like activity than polychlorinated biphenyls (PCBs) and polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs) contributed in some locations (Kannan et al., 1998). However, the identification and quantitation for PCN sources are very scarce compared with PCDD/Fs. Understanding the emission levels and developing the emission inventory of PCNs is important for regulatory and source reduction purposes. In this study, several potential sources were preliminarily investigated for PCN release. Coking process (CP), iron ore sintering (IOS), and electric arc furnace steel making units (AF) were selected due to their huge activity level of industrial production in China. Municipal solid waste incineration (MSWI) and medical waste incineration (MWI) were also investigated because of the possible high concentration of PCNs in stack gas. Two plants were investigated for each thermal related process, except for MWI with one incinerator was investigated. The stack gas samples were collected by automatic isokinetic sampling system (Isostack Basic, TCR TECORA, Milan Italy). Isotope dilution high resolution gas chromatography coupled with high resolution mass spectrometry (HRGC/HRMS) technique was used for the identification and quantitation of PCN congeners. The concentrations of PCNs from the selected thermal processes were determined in this study. The average concentrations of total PCNs were 26 ng Nm-3 for CP, 65 ng Nm-3 for IOS, 720 ng Nm-3 for AF, 443 ng Nm-3 for MSWI, and 45 ng Nm-3 for MWI. The emission factors of PCNs were derived, and the average values were 6 μg tonne-1 for CP, 42 μg tonne-1 for IOS, 2980 μg tonne-1 for AF, 1354 μg tonne-1 for MSWI, and 937 μg tonne-1 for MWI, which could be helpful for estimating the annual emission amounts of PCNs from the investigated sources. However, since the investigated plant numbers for each process are limited, there might be large uncertainties when developing the PCN emission inventory. From the obtained data in the preliminary investigation, it could be seen that these investigated sources are worthy of further concerns for PCN emission. Further investigation on PCN release from thermal related process is still in process. References Kannan, K., Imagawa, T., Blankenship, A.L., et al., 1998. Isomer-specific analysis and toxic evaluation of polychlorinated naphthalenes in soil, sediment, and biota collected near the site of a former chlor-alkali plant. Environ Sci Technol 32, 2507-2514. Lerche, D., van de Plassche, E., Schwegler, A., et al., 2002. Selecting chemical substances for the UN-ECE POP protocol. Chemosphere 47, 617-630. Olivero-Verbel, J., Vivas-Reyes, R., Pacheco-Londono, et al., 2004. Discriminant analysis for activation of the aryl hydrocarbon receptor by polychlorinated naphthalenes. J Mol Struc-Theochem 678, 157-161.

Cell module and fuel conditioner

NASA Technical Reports Server (NTRS)

Hoover, D. Q., Jr.

1981-01-01

The results of the completed tests on Stack 561 and the on-going tests of 562 (23 cell stacks of the MK-1 and M-2 designs respectively) are reported and their performance is compared. Results of the on-going endurance test of Stack 560 (5 cell, MK-2) are reported. Plans for fabrication of Stacks 563 and 564 (23 cell stacks of the MK-1 and MK-2 design) are summarized. Results of the burner tests are given. Excellent performance was achieved on simulated anode exhaust gas over very wide load and air/fuel ranges.

Fabrication of multiwall carbon nanotube sheet based hydrogen sensor on a stacking multi-layer structure.

PubMed

Yan, Keyi; Toku, Yuhki; Morita, Yasuyuki; Ju, Yang

2018-06-22

In this research, we propose a new simple method to fabricate hydrogen gas sensor by stacking the multiwall carbon nanotube (MWCNT) sheets. MWCNT sheet offers a larger surface area and more CNT contacts, which are key factors for gas sensing, because of its super-high alignment and end-to-end structure comparing to the traditional CNT film. Besides, MWCNT sheet can be directly drawn from the spinnable CNT array in large scales. Therefore, this method is a potential answer for the mass production and commercialization of CNT based sensor with high response. By stacking different layers of sheet, microstructure and CNT interactions in the layers were changed and their influences towards gas sensing were investigated. It was observed that the sample with 3 layers of sheet and functionalized with 3 nm-thick Pd showed the best gas sensing performance with a response of 12.31% at 4% H2 and response time below 200 s. © 2018 IOP Publishing Ltd.

Spectral gain profile of a multi-stack terahertz quantum cascade laser

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bachmann, D., E-mail: dominic.bachmann@tuwien.ac.at; Deutsch, C.; Krall, M.

2014-11-03

The spectral gain of a multi-stack terahertz quantum cascade laser, composed of three active regions with emission frequencies centered at 2.3, 2.7, and 3.0 THz, is studied as a function of driving current and temperature using terahertz time-domain spectroscopy. The optical gain associated with the particular quantum cascade stacks clamps at different driving currents and saturates to different values. We attribute these observations to varying pumping efficiencies of the respective upper laser states and to frequency dependent optical losses. The multi-stack active region exhibits a spectral gain full width at half-maximum of 1.1 THz. Bandwidth and spectral position of themore » measured gain match with the broadband laser emission. As the laser action ceases with increasing operating temperature, the gain at the dominant lasing frequency of 2.65 THz degrades sharply.« less

In-ground operation of Geothermic Fuel Cells for unconventional oil and gas recovery

NASA Astrophysics Data System (ADS)

Sullivan, Neal; Anyenya, Gladys; Haun, Buddy; Daubenspeck, Mark; Bonadies, Joseph; Kerr, Rick; Fischer, Bernhard; Wright, Adam; Jones, Gerald; Li, Robert; Wall, Mark; Forbes, Alan; Savage, Marshall

2016-01-01

This paper presents operating and performance characteristics of a nine-stack solid-oxide fuel cell combined-heat-and-power system. Integrated with a natural-gas fuel processor, air compressor, reactant-gas preheater, and diagnostics and control equipment, the system is designed for use in unconventional oil-and-gas processing. Termed a ;Geothermic Fuel Cell; (GFC), the heat liberated by the fuel cell during electricity generation is harnessed to process oil shale into high-quality crude oil and natural gas. The 1.5-kWe SOFC stacks are packaged within three-stack GFC modules. Three GFC modules are mechanically and electrically coupled to a reactant-gas preheater and installed within the earth. During operation, significant heat is conducted from the Geothermic Fuel Cell to the surrounding geology. The complete system was continuously operated on hydrogen and natural-gas fuels for ∼600 h. A quasi-steady operating point was established to favor heat generation (29.1 kWth) over electricity production (4.4 kWe). Thermodynamic analysis reveals a combined-heat-and-power efficiency of 55% at this condition. Heat flux to the geology averaged 3.2 kW m-1 across the 9-m length of the Geothermic Fuel Cell-preheater assembly. System performance is reviewed; some suggestions for improvement are proposed.

Lots of data, how do we use it? Strengths and inaccuracies of utility acid rain electronic data reports

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schott, J.

1996-12-31

Entergy Corporation is a Phase II utility with a fossil generation base composed primarily natural gas and low sulfur coal. This paper presents an analysis of a large Phase II utility`s continuous emissions monitoring data reported to EPA under Title IV Acid Rain. Electric utilities currently report hourly emissions of NOx, SO{sub 2}, CO{sub 2}, fuel use, and generation through electronic data reports to EPA. This paper describes strengths and weaknesses of the data reported to EPA as determined through an analysis of 1995 data. Emissions reported by this company tinder acid rain for SO{sub 2} and NOx are verymore » different from emissions reported to state agencies for annual emission inventory purposes in past years and will represent a significant break with historic trends. A comparison of emissions has been made of 1995 emissions reported under Electronic Data Reports to the emissions that would have been reported using emission factors and fuel data in past years. In addition, the paper examines the impacts of 40 CFR Part 75 Acid Rain requirements such as missing data substitution and monitor bias adjustments. Measurement system errors including stack flow measurement and false NOx Lb/MMBtu readings at very low loads are discussed. This paper describes the implications for public policy, compliance, emissions inventories, and business decisions of Part 75 acid rain monitoring and reporting requirements.« less

Solid State Energy Conversion Energy Alliance (SECA)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hennessy, Daniel; Sibisan, Rodica; Rasmussen, Mike

2011-09-12

The overall objective is to develop a Solid Oxide Fuel Cell (SOFC) stack that can be economically produced in high volumes and mass customized for different applications in transportation, stationary power generation, and military market sectors. In Phase I, work will be conducted on system design and integration, stack development, and development of reformers for natural gas and gasoline. Specifically, Delphi-Battelle will fabricate and test a 5 kW stationary power generation system consisting of a SOFC stack, a steam reformer for natural gas, and balance-of-plant (BOP) components, having an expected efficiency of ≥ 35 percent (AC/LHV). In Phase II andmore » Phase III, the emphasis will be to improve the SOFC stack, reduce start-up time, improve thermal cyclability, demonstrate operation on diesel fuel, and substantially reduce materials and manufacturing cost by integrating several functions into one component and thus reducing the number of components in the system. In Phase II, Delphi-Battelle will fabricate and demonstrate two SOFC systems: an improved stationary power generation system consisting of an improved SOFC stack with integrated reformation of natural gas, and the BOP components, with an expected efficiency of ≥ 40 percent (AC/LHV), and a mobile 5 kW system for heavy-duty trucks and military power applications consisting of an SOFC stack, reformer utilizing anode tailgate recycle for diesel fuel, and BOP components, with an expected efficiency of ≥ 30 percent (DC/LHV). Finally, in Phase III, Delphi-Battelle will fabricate and test a 5 kW Auxiliary Power Unit (APU) for mass-market automotive application consisting of an optimized SOFC stack, an optimized catalytic partial oxidation (CPO) reformer for gasoline, and BOP components, having an expected efficiency of ≥ 30 percent (DC/LHV) and a factory cost of ≤ $400/kW.« less

Solid State Energy Conversion Energy Alliance (SECA)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hennessy, Daniel; Sibisan, Rodica; Rasmussen, Mike

2011-09-12

The overall objective is to develop a solid oxide fuel cell (SOFC) stack that can be economically produced in high volumes and mass customized for different applications in transportation, stationary power generation, and military market sectors. In Phase I, work will be conducted on system design and integration, stack development, and development of reformers for natural gas and gasoline. Specifically, Delphi-Battelle will fabricate and test a 5 kW stationary power generation system consisting of a SOFC stack, a steam reformer for natural gas, and balance-of-plant (BOP) components, having an expected efficiency of 35 percent (AC/LHV). In Phase II and Phasemore » III, the emphasis will be to improve the SOFC stack, reduce start-up time, improve thermal cyclability, demonstrate operation on diesel fuel, and substantially reduce materials and manufacturing cost by integrating several functions into one component and thus reducing the number of components in the system. In Phase II, Delphi-Battelle will fabricate and demonstrate two SOFC systems: an improved stationary power generation system consisting of an improved SOFC stack with integrated reformation of natural gas, and the BOP components, with an expected efficiency of ≥40 percent (AC/LHV), and a mobile 5 kW system for heavy-duty trucks and military power applications consisting of an SOFC stack, reformer utilizing anode tailgate recycle for diesel fuel, and BOP components, with an expected efficiency of ≥30 percent (DC/LHV). Finally, in Phase III, Delphi-Battelle will fabricate and test a 5 kW Auxiliary Power Unit (APU) for mass-market automotive application consisting of an optimized SOFC stack, an optimized catalytic partial oxidation (CPO) reformer for gasoline, and BOP components, having an expected efficiency of 30 percent (DC/LHV) and a factory cost of ≤$400/kW.« less

Dynamic model of a micro-tubular solid oxide fuel cell stack including an integrated cooling system

NASA Astrophysics Data System (ADS)

Hering, Martin; Brouwer, Jacob; Winkler, Wolfgang

2017-02-01

A novel dynamic micro-tubular solid oxide fuel cell (MT-SOFC) and stack model including an integrated cooling system is developed using a quasi three-dimensional, spatially resolved, transient thermodynamic, physical and electrochemical model that accounts for the complex geometrical relations between the cells and cooling-tubes. The modeling approach includes a simplified tubular geometry and stack design including an integrated cooling structure, detailed pressure drop and gas property calculations, the electrical and physical constraints of the stack design that determine the current, as well as control strategies for the temperature. Moreover, an advanced heat transfer balance with detailed radiative heat transfer between the cells and the integrated cooling-tubes, convective heat transfer between the gas flows and the surrounding structures and conductive heat transfer between the solid structures inside of the stack, is included. The detailed model can be used as a design basis for the novel MT-SOFC stack assembly including an integrated cooling system, as well as for the development of a dynamic system control strategy. The evaluated best-case design achieves very high electrical efficiency between around 75 and 55% in the entire power density range between 50 and 550 mW /cm2 due to the novel stack design comprising an integrated cooling structure.

Excellent Field Emission Properties of Short Conical Carbon Nanotubes Prepared by Microwave Plasma Enhanced CVD Process

PubMed Central

2008-01-01

Randomly oriented short and low density conical carbon nanotubes (CNTs) were prepared on Si substrates by tubular microwave plasma enhanced chemical vapor deposition process at relatively low temperature (350–550 °C) by judiciously controlling the microwave power and growth time in C2H2 + NH3gas composition and Fe catalyst. Both length as well as density of the CNTs increased with increasing microwave power. CNTs consisted of regular conical compartments stacked in such a way that their outer diameter remained constant. Majority of the nanotubes had a sharp conical tip (5–20 nm) while its other side was either open or had a cone/pear-shaped catalyst particle. The CNTs were highly crystalline and had many open edges on the outer surface, particularly near the joints of the two compartments. These films showed excellent field emission characteristics. The best emission was observed for a medium density film with the lowest turn-on and threshold fields of 1.0 and 2.10 V/μm, respectively. It is suggested that not only CNT tip but open edges on the body also act as active emission sites in the randomly oriented geometry of such periodic structures.

40 CFR 60.1360 - What records must I keep for stack tests?

Code of Federal Regulations, 2010 CFR

2010-07-01

... measure specified in table 1 of this subpart: (1) Dioxins/furans. (2) Cadmium. (3) Lead. (4) Mercury. (5... control device during all stack tests for dioxins/furans emissions. (d) The calendar date of each record. ...

Radon emissions from natural gas power plants at The Pennsylvania State University.

PubMed

Stidworthy, Alison G; Davis, Kenneth J; Leavey, Jeff

2016-11-01

Burning natural gas in power plants may emit radon ( 222 Rn) into the atmosphere. On the University Park campus of The Pennsylvania State University, atmospheric radon enhancements were measured and modeled in the vicinity of their two power plants. The three-part study first involved measuring ambient outdoor radon concentrations from August 2014 through January 2015 at four sites upwind and downwind of the power plants at distances ranging from 80 m to 310 m. For each plant, one site served as a background site, while three other sites measured radon concentration enhancements downwind. Second, the radon content of natural gas flowing into the power plant was measured, and third, a plume dispersion model was used to predict the radon concentrations downwind of the power plants. These predictions are compared to the measured downwind enhancements in radon to determine whether the observed radon concentration enhancements could be attributed to the power plants' emissions. Atmospheric radon concentrations were consistently low as compared to the EPA action level of 148 Bq m -3 , averaging 34.5 ± 2.7 Bq m -3 around the East Campus Steam Plant (ECSP) and 31.6 ± 2.7 Bq m -3 around the West Campus Steam Plant (WCSP). Significant concentrations of radon, ranging from 516 to 1,240 Bq m -3 , were detected in the natural gas. The measured enhancements downwind of the ECSP averaged 6.2 Bq m -3 compared to modeled enhancements of 0.08 Bq m -3 . Measured enhancements around the WCSP averaged -0.2 Bq m -3 compared to the modeled enhancements of 0.05 Bq m -3 , which were not significant compared to observational error. The comparison of the measured to modeled downwind radon enhancements shows no correlation over time. The measurements of radon levels in the vicinity of the power plants appear to be unaffected by the emissions from the power plants. Radon measurements at sites surrounding power plants that utilize natural gas did not indicate that the radon concentrations originated from the plants' emissions. There were elevated radon concentrations in the natural gas supply flowing into the power plants, but combustion dilution puts the concentration below EPA action levels coming out of the stack, so no hazardous levels were expected downwind. Power plant combustion of natural gas is not likely to pose a radiation health hazard unless very different gas radon concentrations or combustion dilution ratios are encountered.

Stacking multiple connecting functional materials in tandem organic light-emitting diodes

PubMed Central

Zhang, Tao; Wang, Deng-Ke; Jiang, Nan; Lu, Zheng-Hong

2017-01-01

Tandem device is an important architecture in fabricating high performance organic light-emitting diodes and organic photovoltaic cells. The key element in making a high performance tandem device is the connecting materials stack, which plays an important role in electric field distribution, charge generation and charge injection. For a tandem organic light-emitting diode (OLED) with a simple Liq/Al/MoO3 stack, we discovered that there is a significant current lateral spreading causing light emission over an extremely large area outside the OLED pixel when the Al thickness exceeds 2 nm. This spread light emission, caused by an inductive electric field over one of the device unit, limits one’s ability to fabricate high performance tandem devices. To resolve this issue, a new connecting materials stack with a C60 fullerene buffer layer is reported. This new structure permits optimization of the Al metal layer in the connecting stack and thus enables us to fabricate an efficient tandem OLED having a high 155.6 cd/A current efficiency and a low roll-off (or droop) in current efficiency. PMID:28225028

Stacking multiple connecting functional materials in tandem organic light-emitting diodes

NASA Astrophysics Data System (ADS)

Zhang, Tao; Wang, Deng-Ke; Jiang, Nan; Lu, Zheng-Hong

2017-02-01

Tandem device is an important architecture in fabricating high performance organic light-emitting diodes and organic photovoltaic cells. The key element in making a high performance tandem device is the connecting materials stack, which plays an important role in electric field distribution, charge generation and charge injection. For a tandem organic light-emitting diode (OLED) with a simple Liq/Al/MoO3 stack, we discovered that there is a significant current lateral spreading causing light emission over an extremely large area outside the OLED pixel when the Al thickness exceeds 2 nm. This spread light emission, caused by an inductive electric field over one of the device unit, limits one’s ability to fabricate high performance tandem devices. To resolve this issue, a new connecting materials stack with a C60 fullerene buffer layer is reported. This new structure permits optimization of the Al metal layer in the connecting stack and thus enables us to fabricate an efficient tandem OLED having a high 155.6 cd/A current efficiency and a low roll-off (or droop) in current efficiency.

Short protection device for stack of electrolytic cells

DOEpatents

Katz, Murray; Schroll, Craig R.

1985-10-22

Electrical short protection is provided in an electrolytic cell stack by the combination of a thin, nonporous ceramic shield and a noble metal foil disposed on opposite sides of the sealing medium in a gas manifold gasket. The thin ceramic shield, such as alumina, is placed between the porous gasket and the cell stack face at the margins of the negative end plate to the most negative cells to impede ion current flow. The noble metal foil, for instance gold, is electrically coupled to the negative potential of the stack to collect positive ions at a harmless location away from the stack face. Consequently, corrosion products from the stack structure deposit on the foil rather than on the stack face to eliminate electrical shorting of cells at the negative end of the stack.

Assessment of organic contaminants in emissions from refuse-derived fuel combustion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chrostowski, J.; Wait, D.; Kwong, E.

1985-09-01

Organic contaminants in emissions from refuse-derived fuel combustion were investigated in a 20-inch-diameter atmospheric fluidized-bed combustor. Combinations of coal/EcoFuel/MSW/toluene were burned inthe combustor with temperatures ranging from 1250 to 1550 degrees F. A Source Assessment Sampling System (SASS) was used to sample the stack gas; Level 1 methodology was used to analyze the organic-contaminant levels. Combustion efficiencies of 93 to 98 percent were achieved in the test burns. Combustion of the EcoFuel generated fewer organic emissions than combustion of coal at similar combustion temperatures. The fine particulate collected by the SASS train filter contained higher concentrations of extractable organics thanmore » the reactor fly ash and the SASS cyclone samples. Combustion of a toluene/EcoFuel mix generated a large number of benzene derivatives not seen in the combustion of pure EcoFuel. Polycyclic aromatic hydrocarbons were the dominant organic compounds contained in the XAD-2 resin extract from coal combustion. A number of different priority pollutants were identified in the samples collected.« less

The impact of oil burning on kraft recovery furnace SO sub 2 emissions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Someshwar, A.V.; Pinkerton, J.E.; Caron, A.L.

1991-04-01

Auxiliary fossil fuel, either natural gas or fuel oil, is burned in kraft recovery furnaces during furnace startups and shutdowns, furnace upsets, and periods of substantially reduced rates of black liquor firing. The efficiency of sulfur capture and retention during normal operation of a kraft recovery furnace is inherently high. Consequently, not all the SO{sub 2} from occasional burning of sulfur-containing fuel oil in the furnace would be expected to end up in the stack gases. However, the extent to which such SO{sub 2} is captured by the alkali fume generation processes has not been well documented. In this paper,more » the authors examines the impact that burning oil in kraft recovery furnaces has on the SO{sub 2} emissions. The work included analyses of long-term SO{sub 2} data from a continuous emission monitoring system (CEMS) obtained for four furnaces that burned medium sulfur fuel oil as auxiliary fuel. It also included tests conducted on four furnaces in which varying amounts of oil were co-fired with black liquor.« less

VALIDATION OF MERCURY CEMS WHEN COFIRING BIOMASS AT MADISON ELECTRIC'S BLOUNT STATION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dennis L. Laudal; Jeffrey S. Thompson

2000-09-30

The state of Wisconsin has been concerned about mercury deposition into its lakes and streams and has been evaluating strategies to reduce mercury emissions. As part of this effort, the Blount Station, owned and operated by Madison Gas and Electric Company (MGE), has undergone a project to evaluate the effects and potential mercury emissions reduction of cofiring preconsumer waste. MGE owns and operates the Blount Generating Station located in central Madison, Wisconsin. At present, Blount operates with nine boilers and six turbine generators. The two largest boilers at Blount produce 400,000 pounds of steam per hour at 950 F andmore » 1250 psi. These larger boilers, MGE's Boiler Nos. 8 and 9, have the capability of cofiring both paper and plastic. MGE's Blount Generating Station was one of the first electric generating stations in the United States to retrofit its existing steam boilers to successfully burn refuse-derived fuel and other alternate fuels including waste paper and wood. It is the No. 9 boiler that was the focus of this project to determine the effect of cofiring PDF (plastic- and paper-derived fuel) on speciated mercury emissions. The project was laid out to compare four different fuel combinations: (1) coal feed only, (2) coal with plastic, (3) coal with paper, and (4) coal with paper and plastic. The design was to run the boiler for 2 days at each condition, thus allowing four samples to be taken at each condition. This plan was aimed at getting at least three representative samples at each condition and allowed for difficulties in sampling and boiler operation. The following objectives were accomplished as part of the project to determine the effects of cofiring PDF on mercury emissions and speciation at MGE Blount Station: Successfully completed all of the mercury sampling for each of the four boiler/PDF conditions using the Ontario Hydro (OH) mercury speciation method; Determined mercury concentrations at the stack location using mercury continuous emission monitors (CEMs) for each of the four boiler/PDF conditions; Calculated the overall mercury mass balance for each of the runs; Determined chlorine concentrations at the stack location using EPA Method 26A for each of the four boiler/PDF conditions; and Calculated speciated mercury flow to determine removal and/or transformations before its exiting the unit at the stack for each of the four boiler/PDF conditions.« less

Control rod system useable for fuel handling in a gas-cooled nuclear reactor

DOEpatents

Spurrier, Francis R.

1976-11-30

A control rod and its associated drive are used to elevate a complete stack of fuel blocks to a position above the core of a gas-cooled nuclear reactor. A fuel-handling machine grasps the control rod and the drive is unlatched from the rod. The stack and rod are transferred out of the reactor, or to a new location in the reactor, by the fuel-handling machine.

Experimental investigations of stability of static liquid fillets and liquid-gas interface in capillary passages for gas-free liquid acquisition in zero gravity

NASA Astrophysics Data System (ADS)

Purohit, Ghanshyam Purshottamdas

Experimental investigations of static liquid fillets formed between small gaps of a cylindrical surface and a flat surface are carried out. The minimum volume of liquid required to form a stable fillet and the maximum liquid content the fillet can hold before becoming unstable are studied. Fillet shapes are captured in photographs obtained by a high speed image system. Experiments were conducted using water, UPA and PF 5060 on two surfaces-stand-blasted titanium and polished copper for different surface inclinations. Experimental data are generalized using appropriate non-dimensional groups. Analytical model are developed to describe the fillet curvature. Fillet curvature data are compared against model predictions and are found to be in close agreement. Bubble point experiments were carried out to measure the capillary pressure difference across the liquid-gas interface in the channels of photo-chemically etched disk stacks. Experiments were conducted using titanium stacks of five different geometrical configurations. Both well wetting liquids (IPA and PF5060) and partially wetting liquid (water) were used during experiments. Test results are found to be in close agreement with analytical predictions. Experiments were carried out to measure the frictional pressure drop across the stack as a function of liquid flow rate using two different liquids (water and IPA) and five stacks of different geometrical configurations. A channel pressure drop model is developed by treating the flow within stack channels as fully developed laminar flow between parallel plates and solving the one-dimensional Navier Stokes equation. An alternate model is developed by treating the flow in channels as flow within porous media. Expressions are developed for effective porosity and permeability for the stacks and the pressure drop is related to these parameters. Pressure drop test results are found to be in close agreement with model predictions. As a specific application of this work, a surface tension propellant management device (PMD) that uses photo-chemically etched disk stacks as capillary elements is examined. These PMDs are used in gas pressurized liquid propellant tanks to supply gas-free propellant to rocket engines in near zero-gravity environment. The experimentally validated models are integrated to perform key analyses for predicting PMD performance in zero gravity.

40 CFR 61.202 - Standard.

Code of Federal Regulations, 2010 CFR

2010-07-01

... EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS National Emission Standards for Radon Emissions From... the stack does not emit more than 20 pCi/(m2-sec) (1.9 pCi/(ft2-sec)) of radon-222 into the air. [57...

40 CFR 61.202 - Standard.

Code of Federal Regulations, 2011 CFR

2011-07-01

... EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS National Emission Standards for Radon Emissions From... the stack does not emit more than 20 pCi/(m2-sec) (1.9 pCi/(ft2-sec)) of radon-222 into the air. [57...

Physical and chemical characterization of residual oil-fired power plant emissions

EPA Science Inventory

Although the toxicity of oil combustion emissions is a significant public health concern, few studies characterize the emissions from plant-scale utility boilers firing residual oil. This study remedies that deficiency by sampling and monitoring stack emissions from a 432 Giga Jo...

Chemical and biological characterization of emissions from coal- and oil-fired power plants.

PubMed Central

Ahlberg, M; Berghem, L; Nordberg, G; Persson, S A; Rudling, L; Steen, B

1983-01-01

Emission samples were obtained from two medium-sized power plants, one fired with oil and the other with pulverized coal. Particles obtained by a miniscale plume stack gas sampler (MIPSGAS), simulating the dilution process in the plume, were subjected to detailed physical, chemical and biological characterization. Studies by scanning electron microscopy and by Coulter counter demonstrated that the particles from the oil-fired boiler were considerably larger than the particles from the coal-fired boiler. Chemical analyses revealed more organic substances and more S, Ni, V, in the oil than in the coal particles. The latter contained a larger proportion of Al, Si, Cl, K, Ca, Ti, Mn, Fe, Se, Rb, Y, Zr, Ba and Pb. Biological testing revealed a greater acute and subacute toxicity by the intratracheal route in the hamster, a greater toxicity to alveolar macrophages and a greater lung retention of BaP coated on the particles from oil combustion than on those from coal combustion. In another sampling line, employed simultaneously with the MIPSGAS-particulate sampler, the total emissions were collected, i.e., both particle and gas phase. These samples were used for chemical analyses and Ames mutagenicity test. Analyses of specific PAHs in emissions from both plants demonstrated that concentrations were below the detection limit (less than 4 ng/m3 of benzo(a)pyrene), which is in accord with an efficient combustion of the fuel. The mutagenicity of the samples were below the detection limit of the mutagenicity assay. Images FIGURE 4. FIGURE 5. PMID:6825622

Estimation of sulphur dioxide emission rate from a power plant based on the remote sensing measurement with an imaging-DOAS instrument

NASA Astrophysics Data System (ADS)

Chong, Jihyo; Kim, Young J.; Baek, Jongho; Lee, Hanlim

2016-10-01

Major anthropogenic sources of sulphur dioxide in the troposphere include point sources such as power plants and combustion-derived industrial sources. Spatially resolved remote sensing of atmospheric trace gases is desirable for better estimation and validation of emission from those sources. It has been reported that Imaging Differential Optical Absorption Spectroscopy (I-DOAS) technique can provide the spatially resolved two-dimensional distribution measurement of atmospheric trace gases. This study presents the results of I-DOAS observations of SO2 from a large power plant. The stack plume from the Taean coal-fired power plant was remotely sensed with an I-DOAS instrument. The slant column density (SCD) of SO2 was derived by data analysis of the absorption spectra of the scattered sunlight measured by an I-DOAS over the power plant stacks. Two-dimensional distribution of SO2 SCD was obtained over the viewing window of the I-DOAS instrument. The measured SCDs were converted to mixing ratios in order to estimate the rate of SO2 emission from each stack. The maximum mixing ratio of SO2 was measured to be 28.1 ppm with a SCD value of 4.15×1017 molecules/cm2. Based on the exit velocity of the plume from the stack, the emission rate of SO2 was estimated to be 22.54 g/s. Remote sensing of SO2 with an I-DOAS instrument can be very useful for independent estimation and validation of the emission rates from major point sources as well as area sources.

Partitioning coefficients of polycyclic aromatic hydrocarbons in stack gas from a municipal incinerator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, W.M.G.; Chen, J.C.

1995-12-31

In this study, solid-gas partitioning coefficients of PAHs on fly ash in stack gas from a municipal incinerator were determined according to elution analysis with gas-solid chromatography. The fly ash from the electrostatic precipitator was sieved and packed into a 1/4 inch (6.3 mm) pyrex column. Elution analysis with gas-solid chromatography was conducted for three PAEs, Napthalene, Anthracene, and Pyrene. The temperature for elution analysis was in the range of 100{degrees}C to 300{degrees}C. Vg, specific retention volume obtained from elution analysis, and S, specific surface area of fly ash measured by a surface area measurement instrument were used to estimatemore » the solid-gas partitioning coefficient KR. In addition, the relationships between KR and temperature and KR and PAH concentrations were investigated.« less

Air Sample Conditioner Helps the Waste Treatment Plant Meet Emissions Standards

DOE Office of Scientific and Technical Information (OSTI.GOV)

Glissmeyer, John A.; Flaherty, Julia E.; Pekour, Mikhail S.

2014-12-02

The air in three of the Hanford Site Waste Treatment and Immobilization Plant (WTP) melter off-gas discharge stacks will be hot and humid after passing through the train of emission abatement equipment. The off-gas temperature and humidity levels will be incompatible with the airborne emissions monitoring equipment required for this type of stack. To facilitate sampling from these facilities, an air sample conditioner system will be installed to introduce cool, dry air into the sample stream to reduce the temperature and dew point. This will avoid thermal damage to the instrumentation and problematic condensation. The complete sample transport system mustmore » also deliver at least 50% of the particles in the sample airstream to the sample collection and on-line analysis equipment. The primary components of the sample conditioning system were tested in a laboratory setting. The sample conditioner itself is based on a commercially-available porous tube filter design. It consists of a porous sintered metal tube inside a coaxial metal jacket. The hot gas sample stream passes axially through the porous tube, and the dry, cool air is injected into the jacket and through the porous wall of the inner tube, creating an effective sample diluter. The dilution and sample air mix along the entire length of the porous tube, thereby simultaneously reducing the dew point and temperature of the mixed sample stream. Furthermore, because the dilution air enters through the porous tube wall, the sample stream does not come in contact with the porous wall and particle deposition is reduced in this part of the sampling system. Tests were performed with an environmental chamber to supply air with the temperature and humidity needed to simulate the off-gas conditions. Air from the chamber was passed through the conditioning system to test its ability to reduce the temperature and dew point of the sample stream. To measure particle deposition, oil droplets in the range of 9 to 11 micrometer aerodynamic diameter were injected into the environmental chamber and drawn through the conditioning system, which included a filter to capture droplets that passed through the conditioner. The droplets were tagged with a fluorescent dye which allowed quantification of droplet deposition on each component of the system. The tests demonstrated the required reductions in temperature and moisture, with no condensation forming when heat tracing was added on the upstream end of the sample conditioner. Additionally, tests indicated that the system, operating at several flow rates and in both vertical and horizontal orientations, delivers nearly all of the sampled particles for analysis. Typical aerosol penetration values were between 98 and 99%. PNNL, Bechtel National Inc., and the instrument vendor are working to implement the sample conditioner into the air monitoring systems used for the melter off-gas exhaust streams. Similar technology may be useful for processes in other facilities with air exhaust streams with elevated temperature and/or humidity.« less

A Hybrid Seismic Inversion Method for V P/V S Ratio and Its Application to Gas Identification

NASA Astrophysics Data System (ADS)

Guo, Qiang; Zhang, Hongbing; Han, Feilong; Xiao, Wei; Shang, Zuoping

2018-03-01

The ratio of compressional wave velocity to shear wave velocity (V P/V S ratio) has established itself as one of the most important parameters in identifying gas reservoirs. However, considering that seismic inversion process is highly non-linear and geological conditions encountered may be complex, a direct estimation of V P/V S ratio from pre-stack seismic data remains a challenging task. In this paper, we propose a hybrid seismic inversion method to estimate V P/V S ratio directly. In this method, post- and pre-stack inversions are combined in which the pre-stack inversion for V P/V S ratio is driven by the post-stack inversion results (i.e., V P and density). In particular, the V P/V S ratio is considered as a model parameter and is directly inverted from the pre-stack inversion based on the exact Zoeppritz equation. Moreover, anisotropic Markov random field is employed in order to regularise the inversion process as well as taking care of geological structures (boundaries) information. Aided by the proposed hybrid inversion strategy, the directional weighting coefficients incorporated in the anisotropic Markov random field neighbourhoods are quantitatively calculated by the anisotropic diffusion method. The synthetic test demonstrates the effectiveness of the proposed inversion method. In particular, given low quality of the pre-stack data and high heterogeneity of the target layers in the field data, the proposed inversion method reveals the detailed model of V P/V S ratio that can successfully identify the gas-bearing zones.

40 CFR Table 3 to Subpart Ttttt of... - Initial Compliance With Emission Limits

Code of Federal Regulations, 2014 CFR

2014-07-01

... (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES (CONTINUED) National Emissions Standards for Hazardous Air Pollutants for Primary Magnesium... dryer stack a. The average mass flow of particulate matter from the control system applied to emissions...

Application of open-path Fourier transform infrared spectroscopy for atmospheric monitoring of a CO2 back-production experiment at the Ketzin pilot site (Germany).

PubMed

Sauer, Uta; Borsdorf, H; Dietrich, P; Liebscher, A; Möller, I; Martens, S; Möller, F; Schlömer, S; Schütze, C

2018-02-03

During a controlled "back-production experiment" in October 2014 at the Ketzin pilot site, formerly injected CO 2 was retrieved from the storage formation and directly released to the atmosphere via a vent-off stack. Open-path Fourier transform infrared (OP FTIR) spectrometers, on-site meteorological parameter acquisition systems, and distributed CO 2 point sensors monitored gas dispersion processes in the near-surface part of the atmospheric boundary layer. The test site provides a complex and challenging mosaic-like surface setting for atmospheric monitoring which can also be found at other storage sites. The main aims of the atmospheric monitoring of this experiment were (1) to quantify temporal and spatial variations in atmospheric CO 2 concentrations around the emitting vent-off stack and (2) to test if and how atmospheric monitoring can cope with typical environmental and operational challenges. A low environmental risk was encountered during the whole CO 2 back-production experiment. The study confirms that turbulent wind conditions favor atmospheric mixing processes and are responsible for rapid dilution of the released CO 2 leading to decreased detectability at all sensors. In contrast, calm and extremely stable wind conditions (especially occurring during the night) caused an accumulation of gases in the near-ground atmospheric layer with the highest amplitudes in measured gas concentration. As an important benefit of OP FTIR spectroscopic measurements and their ability to detect multiple gas species simultaneously, emission sources could be identified to a much higher certainty. Moreover, even simulation models using simplified assumptions help to find suitable monitoring network designs and support data analysis for certain wind conditions in such a complex environment.

A MOLECULAR STAR FORMATION LAW IN THE ATOMIC-GAS-DOMINATED REGIME IN NEARBY GALAXIES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schruba, Andreas; Walter, Fabian; Dumas, Gaelle

2011-08-15

We use the IRAM HERACLES survey to study CO emission from 33 nearby spiral galaxies down to very low intensities. Using 21 cm line atomic hydrogen (H I) data, mostly from THINGS, we predict the local mean CO velocity based on the mean H I velocity. By re-normalizing the CO velocity axis so that zero corresponds to the local mean H I velocity we are able to stack spectra coherently over large regions. This enables us to measure CO intensities with high significance as low as I{sub CO} {approx} 0.3 K km s{sup -1} ({Sigma}{sub H{sub 2}}{approx}1 M{sub sun} pc{supmore » -2}), an improvement of about one order of magnitude over previous studies. We detect CO out to galactocentric radii r{sub gal} {approx} r{sub 25} and find the CO radial profile to follow a remarkably uniform exponential decline with a scale length of {approx}0.2 r{sub 25}. Here we focus on stacking as a function of radius, comparing our sensitive CO profiles to matched profiles of H I, H{alpha}, far-UV (FUV), and Infrared (IR) emission at 24 {mu}m and 70 {mu}m. We observe a tight, roughly linear relationship between CO and IR intensity that does not show any notable break between regions that are dominated by molecular gas ({Sigma}{sub H{sub 2}}>{Sigma}{sub H{sub i}}) and those dominated by atomic gas ({Sigma}{sub H{sub 2}}<{Sigma}{sub H{sub i}}). We use combinations of FUV+24 {mu}m and H{alpha}+24 {mu}m to estimate the recent star formation rate (SFR) surface density, {Sigma}{sub SFR}, and find approximately linear relations between {Sigma}{sub SFR} and {Sigma}{sub H{sub 2}}. We interpret this as evidence of stars forming in molecular gas with little dependence on the local total gas surface density. While galaxies display small internal variations in the SFR-to-H{sub 2} ratio, we do observe systematic galaxy-to-galaxy variations. These galaxy-to-galaxy variations dominate the scatter in relationships between CO and SFR tracers measured at large scales. The variations have the sense that less massive galaxies exhibit larger ratios of SFR-to-CO than massive galaxies. Unlike the SFR-to-CO ratio, the balance between atomic and molecular gas depends strongly on the total gas surface density and galactocentric radius. It must also depend on additional parameters. Our results reinforce and extend to lower surface densities, a picture in which star formation in galaxies can be separated into two processes: the assembly of star-forming molecular clouds and the formation of stars from H{sub 2}. The interplay between these processes yields a total gas-SFR relation with a changing slope, which has previously been observed and identified as a star formation threshold.« less

Cool white light-emitting three stack OLED structures for AMOLED display applications.

PubMed

Springer, Ramon; Kang, Byoung Yeop; Lampande, Raju; Ahn, Dae Hyun; Lenk, Simone; Reineke, Sebastian; Kwon, Jang Hyuk

2016-11-28

This paper demonstrates 2-stack and 3-stack white organic light-emitting diodes (WOLEDs) with fluorescent blue and phosphorescent yellow emissive units. The 2-stack and 3-stack WOLED comprises blue-yellow and blue-blue-yellow (blue-yellow-blue) combinations. The position of the yellow emitter and possible cavity lengths in different stack architectures are theoretically and experimentally investigated to reach Commission Internationale de L'Eclairage (CIE) coordinates of near (0.333/0.333). Here, a maximum external quantum efficiency (EQE) of 23.6% and current efficiency of 62.2 cd/A at 1000 cd/m² as well as suitable CIE color coordinates of (0.335/0.313) for the blue-blue-yellow 3-stack hybrid WOLED structure is reported. In addition, the blue-yellow-blue 3-stack architecture exhibits an improved angular dependence compared to the blue-blue-yellow structure at a decreased EQE of 19.1%.

40 CFR 61.44 - Stack sampling.

Code of Federal Regulations, 2013 CFR

2013-07-01

... EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS National Emission Standard for Beryllium Rocket Motor... within 30 days after samples are taken and before any subsequent rocket motor firing or propellant...

40 CFR 61.44 - Stack sampling.

Code of Federal Regulations, 2014 CFR

2014-07-01

... EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS National Emission Standard for Beryllium Rocket Motor... within 30 days after samples are taken and before any subsequent rocket motor firing or propellant...

40 CFR 61.44 - Stack sampling.

Code of Federal Regulations, 2012 CFR

2012-07-01

... EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS National Emission Standard for Beryllium Rocket Motor... within 30 days after samples are taken and before any subsequent rocket motor firing or propellant...

40 CFR 62.14412 - What stack opacity and visible emissions requirements apply?

Code of Federal Regulations, 2014 CFR

2014-07-01

... requirements apply? (a) Your HMIWI (regardless of size category) must not discharge into the atmosphere from... atmosphere visible emissions of combustion ash from an ash conveying system (including conveyor transfer... emissions limit does cover visible emissions discharged to the atmosphere from buildings or enclosures of...

40 CFR 62.14412 - What stack opacity and visible emissions requirements apply?

Code of Federal Regulations, 2013 CFR

2013-07-01

... requirements apply? (a) Your HMIWI (regardless of size category) must not discharge into the atmosphere from... atmosphere visible emissions of combustion ash from an ash conveying system (including conveyor transfer... emissions limit does cover visible emissions discharged to the atmosphere from buildings or enclosures of...

40 CFR 61.53 - Stack sampling.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 8 2011-07-01 2011-07-01 false Stack sampling. 61.53 Section 61.53 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL... sampling. (a) Mercury ore processing facility. (1) Unless a waiver of emission testing is obtained under...

40 CFR 61.53 - Stack sampling.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 8 2010-07-01 2010-07-01 false Stack sampling. 61.53 Section 61.53 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL... sampling. (a) Mercury ore processing facility. (1) Unless a waiver of emission testing is obtained under...

Evaluation of the public health risks associated with semivolatile metal and dioxin emissions from hazardous waste incinerators.

PubMed Central

Sedman, R M; Esparza, J R

1991-01-01

The public health impacts associated with stack emissions from hazardous waste incinerators have become a major concern in recent years. Most evaluations of incinerator stack emissions have focused on three classes of compounds: metals, semivolatile, and volatile compounds. These investigations have been complicated by the difficulty and expense of analyzing the emissions and the limited amount of toxicity information for many of the compounds that have been detected. The results of over 20 trial burns at hazardous waste incinerators were assembled in an attempt to determine which compounds may pose a significant threat to the public health. The risks associated with semivolatile emissions were found to be inconsequential, although further study of dioxins and dibenzofurans emissions appears to be warranted. The risk associated with the emission of cadmium and perhaps chromium (VI) may pose a significant risk to public health at certain facilities. Controls on waste feed or air pollution control devices should be employed to reduce the emission of these metals. Any monitoring of metal emissions from hazardous waste incinerators should focus on cadmium and chromium (VI). PMID:1954929

Mercury Dispersion Modeling And Purge Ventilation Stack Height Determination For Tank 40H

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rivera-Giboyeaux, A.

2017-05-19

The SRNL Atmospheric Technologies Group performed an analysis for mercury emissions from H-Tank Farm - Tank 40 ventilation system exhaust in order to assess whether the Short Term Exposure Limit (STEL), or Threshold Limit Value (TLV) levels for mercury will be exceeded during bulk sludge slurry mixing and sludge removal operations. The American Meteorological Society/Environmental Protection Agency Regulatory Model (AERMOD) was used as the main dispersion modelling tool for this analysis. The results indicated that a 45-foot stack is sufficient to raise the plume centerline from the Tank 40 release to prevent mercury exposure problems for any of the stackmore » discharge scenarios provided. However, a 42-foot stack at Tank 40 is sufficient to prevent mercury exposure concerns in all emission scenarios except the 50 mg/m 3 release. At a 42-foot stack height, values exceeding the exposure standards are only measured on receptors located above 34 feet.« less

Stacked Average Far-infrared Spectrum of Dusty Star-forming Galaxies from the Herschel/SPIRE Fourier Transform Spectrometer

NASA Astrophysics Data System (ADS)

Wilson, Derek; Cooray, Asantha; Nayyeri, Hooshang; Bonato, Matteo; Bradford, Charles M.; Clements, David L.; De Zotti, Gianfranco; Díaz-Santos, Tanio; Farrah, Duncan; Magdis, Georgios; Michałowski, Michał J.; Pearson, Chris; Rigopoulou, Dimitra; Valtchanov, Ivan; Wang, Lingyu; Wardlow, Julie

2017-10-01

We present stacked average far-infrared spectra of a sample of 197 dusty star-forming galaxies (DSFGs) at 0.005< z< 4 using about 90% of the Herschel Space Observatory SPIRE Fourier Transform Spectrometer (FTS) extragalactic data archive based on 3.5 years of science operations. These spectra explore an observed-frame 447-1568 GHz frequency range, allowing us to observe the main atomic and molecular lines emitted by gas in the interstellar medium. The sample is subdivided into redshift bins, and a subset of the bins are stacked by infrared luminosity as well. These stacked spectra are used to determine the average gas density and radiation field strength in the photodissociation regions (PDRs) of DSFGs. For the low-redshift sample, we present the average spectral line energy distributions of CO and H2O rotational transitions and consider PDR conditions based on observed [C I] 370 and 609 μm, and CO (7-6) lines. For the high-z (0.8< z< 4) sample, PDR models suggest a molecular gas distribution in the presence of a radiation field that is at least a factor of 103 larger than the Milky Way and with a neutral gas density of roughly {10}4.5-{10}5.5 cm-3. The corresponding PDR models for the low-z sample suggest a UV radiation field and gas density comparable to those at high-z. Given the challenges in obtaining adequate far-infrared observations, the stacked average spectra we present here will remain the measurements with the highest signal-to-noise ratio for at least a decade and a half until the launch of the next far-infrared facility. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

Hardware simulation of fuel cell/gas turbine hybrids

NASA Astrophysics Data System (ADS)

Smith, Thomas Paul

Hybrid solid oxide fuel cell/gas turbine (SOFC/GT) systems offer high efficiency power generation, but face numerous integration and operability challenges. This dissertation addresses the application of hardware-in-the-loop simulation (HILS) to explore the performance of a solid oxide fuel cell stack and gas turbine when combined into a hybrid system. Specifically, this project entailed developing and demonstrating a methodology for coupling a numerical SOFC subsystem model with a gas turbine that has been modified with supplemental process flow and control paths to mimic a hybrid system. This HILS approach was implemented with the U.S. Department of Energy Hybrid Performance Project (HyPer) located at the National Energy Technology Laboratory. By utilizing HILS the facility provides a cost effective and capable platform for characterizing the response of hybrid systems to dynamic variations in operating conditions. HILS of a hybrid system was accomplished by first interfacing a numerical model with operating gas turbine hardware. The real-time SOFC stack model responds to operating turbine flow conditions in order to predict the level of thermal effluent from the SOFC stack. This simulated level of heating then dynamically sets the turbine's "firing" rate to reflect the stack output heat rate. Second, a high-speed computer system with data acquisition capabilities was integrated with the existing controls and sensors of the turbine facility. In the future, this will allow for the utilization of high-fidelity fuel cell models that infer cell performance parameters while still computing the simulation in real-time. Once the integration of the numeric and the hardware simulation components was completed, HILS experiments were conducted to evaluate hybrid system performance. The testing identified non-intuitive transient responses arising from the large thermal capacitance of the stack that are inherent to hybrid systems. Furthermore, the tests demonstrated the capabilities of HILS as a research tool for investigating the dynamic behavior of SOFC/GT hybrid power generation systems.

New design of a PEFC cathode separator of for water management

NASA Astrophysics Data System (ADS)

Sugiura, K.; Takahashi, N.; Kamimura, T.

2017-11-01

Generally, polymer electrolyte fuel cells (PEFCs) need humidifiers to prevent the drying of the membrane, but this use of humidifiers creates water management issues, such as the flooding/plugging phenomena and decreased system efficiency because of an increase in the electric energy needed for auxiliary equipment. Although most researchers have developed high-temperature membranes that do not need humidifiers, a lot of time is necessary for the development of these membranes, and these membranes drive up costs. Therefore, we propose a new cathode separator design that can recycle water generated by power generation in the same cell and a stack structure that can redistribute water collected in the cathode outlet manifold to drying cells. Because the new cathode separator has a bypass channel from the gas outlet to the gas inlet to transport excess water, a dry part in the gas inlet is supplied with excess water in the gas outlet through the bypass channel even if the PEFC is operated under dry conditions. Excess water in the PEFC stack can be transported from the cell with excess water to the drying cell through the cathode outlet manifold with a porous wall. Therefore, we confirm the influence of the plugging phenomenon in the cathode gas outlet manifold on the cell performance of each cell in the stack. As a result, the cell performance of the new cathode separator design is better than that of the standard separator under the low humidity conditions. We confirm that the plugging phenomenon in the cathode outlet manifold affects the cell performance of each cell in the stack.

Co-flow anode/cathode supply heat exchanger for a solid-oxide fuel cell assembly

DOEpatents

Haltiner, Jr., Karl J.; Kelly, Sean M.

2005-11-22

In a solid-oxide fuel cell assembly, a co-flow heat exchanger is provided in the flow paths of the reformate gas and the cathode air ahead of the fuel cell stack, the reformate gas being on one side of the exchanger and the cathode air being on the other. The reformate gas is at a substantially higher temperature than is desired in the stack, and the cathode gas is substantially cooler than desired. In the co-flow heat exchanger, the temperatures of the reformate and cathode streams converge to nearly the same temperature at the outlet of the exchanger. Preferably, the heat exchanger is formed within an integrated component manifold (ICM) for a solid-oxide fuel cell assembly.

Economic and environmental comparison of conventional, hybrid, electric and hydrogen fuel cell vehicles

NASA Astrophysics Data System (ADS)

Granovskii, Mikhail; Dincer, Ibrahim; Rosen, Marc A.

Published data from various sources are used to perform economic and environmental comparisons of four types of vehicles: conventional, hybrid, electric and hydrogen fuel cell. The production and utilization stages of the vehicles are taken into consideration. The comparison is based on a mathematical procedure, which includes normalization of economic indicators (prices of vehicles and fuels during the vehicle life and driving range) and environmental indicators (greenhouse gas and air pollution emissions), and evaluation of an optimal relationship between the types of vehicles in the fleet. According to the comparison, hybrid and electric cars exhibit advantages over the other types. The economic efficiency and environmental impact of electric car use depends substantially on the source of the electricity. If the electricity comes from renewable energy sources, the electric car is advantageous compared to the hybrid. If electricity comes from fossil fuels, the electric car remains competitive only if the electricity is generated on board. It is shown that, if electricity is generated with an efficiency of about 50-60% by a gas turbine engine connected to a high-capacity battery and an electric motor, the electric car becomes advantageous. Implementation of fuel cells stacks and ion conductive membranes into gas turbine cycles permits electricity generation to increase to the above-mentioned level and air pollution emissions to decrease. It is concluded that the electric car with on-board electricity generation represents a significant and flexible advance in the development of efficient and ecologically benign vehicles.

Molten carbonate fuel cell

DOEpatents

Kaun, Thomas D.; Smith, James L.

1987-01-01

A molten electrolyte fuel cell with an array of stacked cells and cell enclosures isolating each cell except for access to gas manifolds for the supply of fuel or oxidant gas or the removal of waste gas, the cell enclosures collectively providing an enclosure for the array and effectively avoiding the problems of electrolyte migration and the previous need for compression of stack components, the fuel cell further including an inner housing about and in cooperation with the array enclosure to provide a manifold system with isolated chambers for the supply and removal of gases. An external insulated housing about the inner housing provides thermal isolation to the cell components.

Molten carbonate fuel cell

DOEpatents

Kaun, T.D.; Smith, J.L.

1986-07-08

A molten electrolyte fuel cell is disclosed with an array of stacked cells and cell enclosures isolating each cell except for access to gas manifolds for the supply of fuel or oxidant gas or the removal of waste gas. The cell enclosures collectively provide an enclosure for the array and effectively avoid the problems of electrolyte migration and the previous need for compression of stack components. The fuel cell further includes an inner housing about and in cooperation with the array enclosure to provide a manifold system with isolated chambers for the supply and removal of gases. An external insulated housing about the inner housing provides thermal isolation to the cell components.

Progress in the planar CPn SOFC system design verification

DOE Office of Scientific and Technical Information (OSTI.GOV)

Elangovan, S.; Hartvigsen, J.; Khandkar, A.

1996-04-01

SOFCo is developing a high efficiency, modular and scaleable planar SOFC module termed the CPn design. This design has been verified in a 1.4 kW module test operated directly on pipeline natural gas. The design features multistage oxidation of fuel wherein the fuel is consumed incrementally over several stages. High efficiency is achieved by uniform current density distribution per stage, which lowers the stack resistance. Additional benefits include thermal regulation and compactness. Test results from stack modules operating in pipeline natural gas are presented.

At-Sea Test and Evaluation Of Oxygen (O2) Analyzers.

DTIC Science & Technology

1981-04-01

Paramagnetic Oxygen Analyzer 2-6 2.4 Thermomagnetic Oxygen Analyzer Sensor 2-8 2.5 Cell Voltage versus Oxygen Concentration at 2-11 Various Cell ...of flue gas out of the stack across the cell and back into the stack. In-situ units place the cell directly in the flue gas path in the uptake. ) The...repetitive failurc of a cell heater temperature control circuit and a control cabinet electron- ic malfunction. Of the five (5) units that remained in

Detectability of cold streams into high-redshift galaxies by absorption lines

NASA Astrophysics Data System (ADS)

Goerdt, Tobias; Dekel, Avishai; Sternberg, Amiel; Gnat, Orly; Ceverino, Daniel

2012-08-01

Cold gas streaming along the dark matter filaments of the cosmic web is predicted to be the major source of fuel for disc buildup, violent disc instability and star formation in massive galaxies at high redshift. We investigate to what extent such cold gas is detectable in the extended circumgalactic environment of galaxies via Lyα absorption and selected low-ionization metal absorption lines. We model the expected absorption signatures using high-resolution zoom-in adaptive mesh refinement cosmological simulations. In the post-processing, we distinguish between self-shielded gas and unshielded gas. In the self-shielded gas, which is optically thick to Lyman continuum radiation, we assume pure collisional ionization for species with an ionization potential greater than 13.6 eV. In the optically-thin, unshielded gas, these species are also photoionized by the metagalactic radiation. In addition to absorption of radiation from background quasars, we compute the absorption line profiles of radiation emitted by the galaxy at the centre of the same halo. We predict the strength of the absorption signal for individual galaxies without stacking. We find that the Lyα absorption profiles produced by the streams are consistent with observations of absorption and emission Lyα profiles in high-redshift galaxies. Due to the low metallicities in the streams, and their low covering factors, the metal absorption features are weak and difficult to detect.

Low-Cost High-Pressure Hydrogen Generator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cropley, Cecelia C.; Norman, Timothy J.

Electrolysis of water, particularly in conjunction with renewable energy sources, is potentially a cost-effective and environmentally friendly method of producing hydrogen at dispersed forecourt sites, such as automotive fueling stations. The primary feedstock for an electrolyzer is electricity, which could be produced by renewable sources such as wind or solar that do not produce carbon dioxide or other greenhouse gas emissions. However, state-of-the-art electrolyzer systems are not economically competitive for forecourt hydrogen production due to their high capital and operating costs, particularly the cost of the electricity used by the electrolyzer stack. In this project, Giner Electrochemical Systems, LLC (GES)more » developed a low cost, high efficiency proton-exchange membrane (PEM) electrolysis system for hydrogen production at moderate pressure (300 to 400 psig). The electrolyzer stack operates at differential pressure, with hydrogen produced at moderate pressure while oxygen is evolved at near-atmospheric pressure, reducing the cost of the water feed and oxygen handling subsystems. The project included basic research on catalysts and membranes to improve the efficiency of the electrolysis reaction as well as development of advanced materials and component fabrication methods to reduce the capital cost of the electrolyzer stack and system. The project culminated in delivery of a prototype electrolyzer module to the National Renewable Energy Laboratory for testing at the National Wind Technology Center. Electrolysis cell efficiency of 72% (based on the lower heating value of hydrogen) was demonstrated using an advanced high-strength membrane developed in this project. This membrane would enable the electrolyzer system to exceed the DOE 2012 efficiency target of 69%. GES significantly reduced the capital cost of a PEM electrolyzer stack through development of low cost components and fabrication methods, including a 60% reduction in stack parts count. Economic analysis indicates that hydrogen could be produced for $3.79 per gge at an electricity cost of $0.05/kWh by the lower-cost PEM electrolyzer developed in this project, assuming high-volume production of large-scale electrolyzer systems.« less

40 CFR 63.1352 - Additional test methods.

Code of Federal Regulations, 2013 CFR

2013-07-01

...) National Emission Standards for Hazardous Air Pollutants From the Portland Cement Manufacturing Industry... determine the rates of emission of HCl from kilns and associated bypass stacks at portland cement... emission of specific organic HAP from raw material dryers, and kilns at Portland cement manufacturing...

Preliminary design of a prototype particulate stack sampler. [For stack gas temperature under 300/sup 0/C

DOE Office of Scientific and Technical Information (OSTI.GOV)

Elder, J.C.; Littlefield, L.G.; Tillery, M.I.

1978-06-01

A preliminary design of a prototype particulate stack sampler (PPSS) has been prepared, and development of several components is under way. The objective of this Environmental Protection Agency (EPA)-sponsored program is to develop and demonstrate a prototype sampler with capabilities similar to EPA Method 5 apparatus but without some of the more troublesome aspects. Features of the new design include higher sampling flow; display (on demand) of all variables and periodic calculation of percent isokinetic, sample volume, and stack velocity; automatic control of probe and filter heaters; stainless steel surfaces in contact with the sample stream; single-point particle size separationmore » in the probe nozzle; null-probe capability in the nozzle; and lower weight in the components of the sampling train. Design considerations will limit use of the PPSS to stack gas temperatures under approximately 300/sup 0/C, which will exclude sampling some high-temperature stacks such as incinerators. Although need for filter weighing has not been eliminated in the new design, introduction of a variable-slit virtual impactor nozzle may eliminate the need for mass analysis of particles washed from the probe. Component development has shown some promise for continuous humidity measurement by an in-line wet-bulb, dry-bulb psychrometer.« less

40 CFR 61.33 - Stack sampling.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 8 2010-07-01 2010-07-01 false Stack sampling. 61.33 Section 61.33 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL... sampling. (a) Unless a waiver of emission testing is obtained under § 61.13, each owner or operator...

40 CFR 61.33 - Stack sampling.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 8 2011-07-01 2011-07-01 false Stack sampling. 61.33 Section 61.33 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL... sampling. (a) Unless a waiver of emission testing is obtained under § 61.13, each owner or operator...

40 CFR 60.713 - Compliance provisions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... operator of the affected coating operation shall perform a liquid-liquid VOC material balance over each and... emission control device (other than a fixed-bed carbon adsorption system with individual exhaust stacks for...) when a fixed-bed carbon adsorption system with individual exhaust stacks for each adsorber vessel is...

40 CFR 60.713 - Compliance provisions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... operator of the affected coating operation shall perform a liquid-liquid VOC material balance over each and... emission control device (other than a fixed-bed carbon adsorption system with individual exhaust stacks for...) when a fixed-bed carbon adsorption system with individual exhaust stacks for each adsorber vessel is...

40 CFR 60.713 - Compliance provisions.

Code of Federal Regulations, 2012 CFR

2012-07-01

... operator of the affected coating operation shall perform a liquid-liquid VOC material balance over each and... emission control device (other than a fixed-bed carbon adsorption system with individual exhaust stacks for...) when a fixed-bed carbon adsorption system with individual exhaust stacks for each adsorber vessel is...

AN ELECTROCHEMICAL SYSTEM FOR REMOVING AND RECOVERING ELEMENTAL MERCURY FROM FLUE-STACK GASES

EPA Science Inventory

the impending EPA regulations on the control of mercury emissions from the flue stacks of coal-burning electric utilities has resulted in heightened interest in the development of advanced mercury control technologies such as sorbent injection and in-situ mercury oxidation. Altho...

40 CFR 52.1532 - Stack height review.

Code of Federal Regulations, 2012 CFR

2012-07-01

...) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS (CONTINUED) New Hampshire § 52.1532 Stack height review. The State of New Hampshire has declared to the satisfaction of EPA that no existing emission... the New Hampshire SIP and our delegated PSD authority, the New Hampshire Air Resources Agency will...

40 CFR 52.1532 - Stack height review.

Code of Federal Regulations, 2014 CFR

2014-07-01

...) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS (CONTINUED) New Hampshire § 52.1532 Stack height review. The State of New Hampshire has declared to the satisfaction of EPA that no existing emission... the New Hampshire SIP and our delegated PSD authority, the New Hampshire Air Resources Agency will...

40 CFR 52.1532 - Stack height review.

Code of Federal Regulations, 2013 CFR

2013-07-01

...) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS (CONTINUED) New Hampshire § 52.1532 Stack height review. The State of New Hampshire has declared to the satisfaction of EPA that no existing emission... the New Hampshire SIP and our delegated PSD authority, the New Hampshire Air Resources Agency will...

40 CFR 52.1532 - Stack height review.

Code of Federal Regulations, 2010 CFR

2010-07-01

...) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS (CONTINUED) New Hampshire § 52.1532 Stack height review. The State of New Hampshire has declared to the satisfaction of EPA that no existing emission... the New Hampshire SIP and our delegated PSD authority, the New Hampshire Air Resources Agency will...

40 CFR 52.1532 - Stack height review.

Code of Federal Regulations, 2011 CFR

2011-07-01

...) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS (CONTINUED) New Hampshire § 52.1532 Stack height review. The State of New Hampshire has declared to the satisfaction of EPA that no existing emission... the New Hampshire SIP and our delegated PSD authority, the New Hampshire Air Resources Agency will...

40 CFR 503.40 - Applicability.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SEWAGE SLUDGE STANDARDS FOR THE USE OR... sewage sludge incinerator stack is monitored continuously for carbon monoxide. (2) The monthly average concentration of carbon monoxide in the exit gas from a sewage sludge incinerator stack, corrected for zero...

Real-time radon monitoring at Stromboli volcano: influence of environmental parameters on 222Rn degassing

NASA Astrophysics Data System (ADS)

Cigolini, C.; Ripepe, M.; Poggi, P.; Laiolo, M.

2008-12-01

Two real-time stations for radon monitoring are currently operative at Stromboli volcano. The 222Rn electronic dosimeters are interfaced with an electronic board connected to a radiomodem for wireless data transfer (through a directional antenna) to a receiving station at the volcano observatory (COA). Radon activity data and enviromental parameters (soil temperature and atmospheric pressure) are sampled every 15 minutes and are instantaneously elaborated and transferred via web so that they can be checked in remote. Collected time series show that there is an overall inverse correlation between radon emissions and seasonal temperature variations. Signal processing analysis show that radon emissions in sectors of diffuse degassing are modulated by tidal forces as well. In addition, radon activities recorded at the summit station, located along the summit fracture zone where the gas flux is concentrated, are positively correlated with changes in atmospheric pressure and confirm the occurrence of the 'atmospheric stack effect'. It is not excluded that this process may play an active role in modulating Stromboli explosivity.

Pressure Dome for High-Pressure Electrolyzer

NASA Technical Reports Server (NTRS)

Norman, Timothy; Schmitt, Edwin

2012-01-01

A high-strength, low-weight pressure vessel dome was designed specifically to house a high-pressure [2,000 psi (approx. = 13.8 MPa)] electrolyzer. In operation, the dome is filled with an inert gas pressurized to roughly 100 psi (approx. = 690 kPa) above the high, balanced pressure product oxygen and hydrogen gas streams. The inert gas acts to reduce the clamping load on electrolyzer stack tie bolts since the dome pressure acting axially inward helps offset the outward axial forces from the stack gas pressure. Likewise, radial and circumferential stresses on electrolyzer frames are minimized. Because the dome is operated at a higher pressure than the electrolyzer product gas, any external electrolyzer leak prevents oxygen or hydrogen from leaking into the dome. Instead the affected stack gas stream pressure rises detectably, thereby enabling a system shutdown. All electrical and fluid connections to the stack are made inside the pressure dome and require special plumbing and electrical dome interfaces for this to be accomplished. Further benefits of the dome are that it can act as a containment shield in the unlikely event of a catastrophic failure. Studies indicate that, for a given active area (and hence, cell ID), frame outside diameter must become ever larger to support stresses at higher operating pressures. This can lead to a large footprint and increased costs associated with thicker and/or larger diameter end-plates, tie-rods, and the frames themselves. One solution is to employ rings that fit snugly around the frame. This complicates stack assembly and is sometimes difficult to achieve in practice, as its success is strongly dependent on frame and ring tolerances, gas pressure, and operating temperature. A pressure dome permits an otherwise low-pressure stack to operate at higher pressures without growing the electrolyzer hardware. The pressure dome consists of two machined segments. An O-ring is placed in an O-ring groove in the flange of the bottom segment and is trapped by the flange on the top dome segment when these components are bolted together with high-strength bolts. The pressure dome has several unique features. It is made (to ASME Pressure Vessel guidelines) in a high-strength aluminum alloy with the strength of stainless steel and the weight benefits of aluminum. The flange of the upper dome portion contains specially machined flats for mounting the dome, and other flats dedicated to the special feedthroughs for electrical connections. A pressure dome can be increased in length to house larger stacks (more cells) of the same diameter with the simple addition of a cylindrical segment. To aid in dome assembly, two stainless steel rings are employed. One is used beneath the heads of the high-strength bolts in lieu of individual hardened washers, and another is used instead of individual nuts. Like electrolyzers could be operated at low or high pressures simply by operating the electrolyzer outside or inside a pressurized dome.

The outskirts of galaxy clusters: astrophysics and cosmology

NASA Astrophysics Data System (ADS)

Morandi, Andrea; Sun, Ming

2017-08-01

Exploring the virialization region of galaxy clusters has recently raised the attention of the scientific community, offering a direct view of structure formation. In this talk, I will present recent results on the physical properties of the intracluster medium in the outer volumes of a sample of 320 clusters (0.056 3 keV) in the Chandra archive, with a total integration time of ~20 Ms. We stacked the emission measure profiles of the clusters to detect a signal out to R100. We then measured the average emission measure, gas density and gas fraction, which scale according to the self-similar model of cluster formation. We observe a steepening of the density profiles beyond R500 with slope β~0.68 at R500 and β~1 at R200 and beyond. By tracking the direction of the cosmic filaments where the clusters are embedded, we report that galaxy clusters deviate from spherical symmetry. We finally used, for the first time, the high level of similarity of the emission measure in the cluster outskirts as cosmology proxy. The cosmological parameters are thus constrained assuming that the emission measure profiles at different redshift are weakly self-similar, that is their shape is universal, explicitly allowing for temperature and redshift dependence of the gas fraction. This cosmological test, in combination with Planck+SNIa data, allows us to put a tight constraint on the dark energy models. For a constant-w model, we have w=-1.010±0.030 and Ωm=0.311±0.014, while for a time-evolving equation of state of dark energy w(z) we have Ωm=0.308±0.017, w0=-0.993±0.046 and wa=-0.123±0.400 We checked that our method is robust towards different sources of systematics, including background modelling, outlier measurements, selection effects, inhomogeneities of the gas distribution and cosmic filaments. We also provided for the first time constraints on which definition of cluster boundary radius is more tenable, namely based on a fixed overdensity with respect to the critical density of the Universe. Finally, we present gas inhomogeneities measurements of the outskirts of the poor galaxy group NGC2563.

Very low emissions of airborne particulate pollutants measured from two municipal solid waste incineration plants in Switzerland

NASA Astrophysics Data System (ADS)

Setyan, Ari; Patrick, Michael; Wang, Jing

2017-10-01

A field campaign has been performed in two municipal solid waste incineration (MSWI) plants in Switzerland, at Hinwil (ZH) and Giubiasco (TI). The aim was to measure airborne pollutants at different locations of the abatement systems (including those released from the stacks into the atmosphere) and at a near-field (∼1 km) downwind site, in order to assess the efficiency of the abatement systems and the environmental impact of these plants. During this study, we measured the particle number concentration with a condensation particle counter (CPC), and the size distribution with a scanning mobility particle sizer (SMPS) and an aerodynamic particle sizer (APS). We also sampled particles on filters for subsequent analyses of the morphology, size and elemental composition with a scanning electron microscope coupled to an energy dispersive X-ray spectroscope (SEM/EDX), and of water soluble ions by ion chromatography (IC). Finally, volatile organic compounds (VOCs) were sampled on adsorbing cartridges and analyzed by thermal desorption-gas chromatography/mass spectrometry (TD-GC/MS), and a portable gas analyzer was used to monitor NO, SO2, CO, CO2, and O2. The particle concentration decreased significantly at two locations of the plants: at the electrostatic precipitator and the bag-house filter. The particle concentrations measured at the stacks were very low (<100 #/cm3), stressing the efficiency of the abatement system of the two plants. At Hinwil, particles sampled at the stack were mainly constituted of NaCl and KCl, two salts known to be involved in the corrosion process in incinerators. At Giubiasco, no significant differences were observed for the morphology and chemical composition of the particles collected in the ambient background and at the downwind site, suggesting that the incineration plant released very limited amounts of particles to the surrounding areas.

Development and Applications of a Stage Stacking Procedure

NASA Technical Reports Server (NTRS)

Kulkarni, Sameer; Celestina, Mark L.; Adamczyk, John J.

2012-01-01

The preliminary design of multistage axial compressors in gas turbine engines is typically accomplished with mean-line methods. These methods, which rely on empirical correlations, estimate compressor performance well near the design point, but may become less reliable off-design. For land-based applications of gas turbine engines, off-design performance estimates are becoming increasingly important, as turbine plant operators desire peaking or load-following capabilities and hot-day operability. The current work develops a one-dimensional stage stacking procedure, including a newly defined blockage term, which is used to estimate the off-design performance and operability range of a 13-stage axial compressor used in a power generating gas turbine engine. The new blockage term is defined to give mathematical closure on static pressure, and values of blockage are shown to collapse to curves as a function of stage inlet flow coefficient and corrected shaft speed. In addition to these blockage curves, the stage stacking procedure utilizes stage characteristics of ideal work coefficient and adiabatic efficiency. These curves are constructed using flow information extracted from computational fluid dynamics (CFD) simulations of groups of stages within the compressor. Performance estimates resulting from the stage stacking procedure are shown to match the results of CFD simulations of the entire compressor to within 1.6% in overall total pressure ratio and within 0.3 points in overall adiabatic efficiency. Utility of the stage stacking procedure is demonstrated by estimation of the minimum corrected speed which allows stable operation of the compressor. Further utility of the stage stacking procedure is demonstrated with a bleed sensitivity study, which estimates a bleed schedule to expand the compressors operating range.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Andrews, V.E.

Naturally occurring radioactivity was measured in the atmospheric emissions and process materials of a thermal phosphate (elemental phosphorus) plant. Representative exhaust stack samples were collected from each process in the plant. The phosphate ore contained 12 to 20 parts per million uranium. Processes, emission points, and emission controls are described. Radioactivity concentrations and emission rates from the sources sampled are given.

Remote fire stack igniter. [with solenoid-controlled valve

NASA Technical Reports Server (NTRS)

Ray, W. L. (Inventor)

1974-01-01

An igniter is described mounted on a vent stack with an upper, flame cage near the top of the stack to ignite emissions from the stack. The igniter is a tube with a lower, open, flared end having a spark plug near the lower end and a solenoid-controlled valve which supplies propane fuel from a supply tank. Propane from the tank is supplied at the top under control of a second, solenoid-controlled valve. The valve controlling the lower supply is closed after ignition at the flame cage. The igniter is economical, practical, and highly reliable.

PCDD/F emissions from light-duty diesel vehicles operated under highway conditions and a diesel-engine based power generator.

PubMed

Rey, M D; Font, R; Aracil, I

2014-08-15

PCDD/F emissions from three light-duty diesel vehicles--two vans and a passenger car--have been measured in on-road conditions. We propose a new methodology for small vehicles: a sample of exhaust gas is collected by means of equipment based on United States Environmental Protection Agency (U.S. EPA) method 23 A for stationary stack emissions. The concentrations of O2, CO, CO2, NO, NO2 and SO2 have also been measured. Six tests were carried out at 90-100 km/h on a route 100 km long. Two additional tests were done during the first 10 min and the following 60 min of the run to assess the effect of the engine temperature on PCDD/F emissions. The emission factors obtained for the vans varied from 1800 to 8400 pg I-TEQ/Nm(3) for a 2004 model year van and 490-580 pg I-TEQ/Nm(3) for a 2006 model year van. Regarding the passenger car, one run was done in the presence of a catalyst and another without, obtaining emission factors (330-880 pg I-TEQ/Nm(3)) comparable to those of the modern van. Two other tests were carried out on a power generator leading to emission factors ranging from 31 to 78 pg I-TEQ/Nm(3). All the results are discussed and compared with literature. Copyright © 2014 Elsevier B.V. All rights reserved.

TOXICOLOGICAL EVALUATION OF REALISTIC EMISSIONS OF SOURCE AEROSOLS (TERESA): APPLICATION TO POWER PLANT-DERIVED PM2.5

DOE Office of Scientific and Technical Information (OSTI.GOV)

Annette Rohr

2006-03-01

TERESA (Toxicological Evaluation of Realistic Emissions of Source Aerosols) involves exposing laboratory rats to realistic coal-fired power plant and mobile source emissions to help determine the relative toxicity of these PM sources. There are three coal-fired power plants in the TERESA program; this report describes the results of fieldwork conducted at the first plant, located in the Upper Midwest. The project was technically challenging by virtue of its novel design and requirement for the development of new techniques. By examining aged, atmospherically transformed aerosol derived from power plant stack emissions, we were able to evaluate the toxicity of PM derivedmore » from coal combustion in a manner that more accurately reflects the exposure of concern than existing methodologies. TERESA also involves assessment of actual plant emissions in a field setting--an important strength since it reduces the question of representativeness of emissions. A sampling system was developed and assembled to draw emissions from the stack; stack sampling conducted according to standard EPA protocol suggested that the sampled emissions are representative of those exiting the stack into the atmosphere. Two mobile laboratories were then outfitted for the study: (1) a chemical laboratory in which the atmospheric aging was conducted and which housed the bulk of the analytical equipment; and (2) a toxicological laboratory, which contained animal caging and the exposure apparatus. Animal exposures were carried out from May-November 2004 to a number of simulated atmospheric scenarios. Toxicological endpoints included (1) pulmonary function and breathing pattern; (2) bronchoalveolar lavage fluid cytological and biochemical analyses; (3) blood cytological analyses; (4) in vivo oxidative stress in heart and lung tissue; and (5) heart and lung histopathology. Results indicated no differences between exposed and control animals in any of the endpoints examined. Exposure concentrations for the scenarios utilizing secondary particles (oxidized emissions) ranged from 70-256 {micro}g/m{sup 3}, and some of the atmospheres contained high acidity levels (up to 49 {micro}g/m{sup 3} equivalent of sulfuric acid). However, caution must be used in generalizing these results to other power plants utilizing different coal types and with different plant configurations, as the emissions may vary based on these factors.« less

40 CFR 60.61 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... cement by either the wet or dry process. (b) Bypass means any system that prevents all or a portion of the kiln or clinker cooler exhaust gases from entering the main control device and ducts the gases... cooler emissions. (c) Bypass stack means the stack that vents exhaust gases to the atmosphere from the...

40 CFR 60.61 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-07-01

... cement by either the wet or dry process. (b) Bypass means any system that prevents all or a portion of the kiln or clinker cooler exhaust gases from entering the main control device and ducts the gases... cooler emissions. (c) Bypass stack means the stack that vents exhaust gases to the atmosphere from the...

40 CFR 60.61 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-07-01

... cement by either the wet or dry process. (b) Bypass means any system that prevents all or a portion of the kiln or clinker cooler exhaust gases from entering the main control device and ducts the gases... cooler emissions. (c) Bypass stack means the stack that vents exhaust gases to the atmosphere from the...

40 CFR 60.61 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... cement by either the wet or dry process. (b) Bypass means any system that prevents all or a portion of the kiln or clinker cooler exhaust gases from entering the main control device and ducts the gases... cooler emissions. (c) Bypass stack means the stack that vents exhaust gases to the atmosphere from the...

40 CFR 60.61 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-07-01

... cement by either the wet or dry process. (b) Bypass means any system that prevents all or a portion of the kiln or clinker cooler exhaust gases from entering the main control device and ducts the gases... cooler emissions. (c) Bypass stack means the stack that vents exhaust gases to the atmosphere from the...

40 CFR 60.672 - Standard for particulate matter (PM).

Code of Federal Regulations, 2011 CFR

2011-07-01

... compliance requirements in Table 2 of this subpart. This exemption from the stack PM concentration limit does... Nonmetallic Mineral Processing Plants § 60.672 Standard for particulate matter (PM). (a) Affected facilities must meet the stack emission limits and compliance requirements in Table 2 of this subpart within 60...

40 CFR 60.672 - Standard for particulate matter (PM).

Code of Federal Regulations, 2010 CFR

2010-07-01

... compliance requirements in Table 2 of this subpart. This exemption from the stack PM concentration limit does... Nonmetallic Mineral Processing Plants § 60.672 Standard for particulate matter (PM). (a) Affected facilities must meet the stack emission limits and compliance requirements in Table 2 of this subpart within 60...

The Evolution of Interstellar Medium Mass Probed by Dust Emission: ALMA Observations at z = 0.3-2

NASA Astrophysics Data System (ADS)

Scoville, N.; Aussel, H.; Sheth, K.; Scott, K. S.; Sanders, D.; Ivison, R.; Pope, A.; Capak, P.; Vanden Bout, P.; Manohar, S.; Kartaltepe, J.; Robertson, B.; Lilly, S.

2014-03-01

The use of submillimeter dust continuum emission to probe the mass of interstellar dust and gas in galaxies is empirically calibrated using samples of local star-forming galaxies, Planck observations of the Milky Way, and high-redshift submillimeter galaxies. All of these objects suggest a similar calibration, strongly supporting the view that the Rayleigh-Jeans tail of the dust emission can be used as an accurate and very fast probe of the interstellar medium (ISM) in galaxies. We present ALMA Cycle 0 observations of the Band 7 (350 GHz) dust emission in 107 galaxies from z = 0.2 to 2.5. Three samples of galaxies with a total of 101 galaxies were stellar-mass-selected from COSMOS to have M * ~= 1011 M ⊙: 37 at z ~ 0.4, 33 at z ~ 0.9, and 31 at z = 2. A fourth sample with six infrared-luminous galaxies at z = 2 was observed for comparison with the purely mass-selected samples. From the fluxes detected in the stacked images for each sample, we find that the ISM content has decreased by a factor ~6 from 1 to 2 × 1010 M ⊙ at both z = 2 and 0.9 down to ~2 × 109 M ⊙ at z = 0.4. The infrared-luminous sample at z = 2 shows a further ~4 times increase in M ISM compared with the equivalent non-infrared-bright sample at the same redshift. The gas mass fractions are ~2% ± 0.5%, 12% ± 3%, 14% ± 2%, and 53% ± 3% for the four subsamples (z = 0.4, 0.9, and 2 and infrared-bright galaxies).

Tunable Emission Wavelength Stacked InAs/GaAs Quantum Dots by Chemical Beam Epitaxy for Optical Coherence Tomography

PubMed Central

Ilahi, Bouraoui; Zribi, Jihene; Guillotte, Maxime; Arès, Richard; Aimez, Vincent; Morris, Denis

2016-01-01

We report on Chemical Beam Epitaxy (CBE) growth of wavelength tunable InAs/GaAs quantum dots (QD) based superluminescent diode’s active layer suitable for Optical Coherence Tomography (OCT). The In-flush technique has been employed to fabricate QD with controllable heights, from 5 nm down to 2 nm, allowing a tunable emission band over 160 nm. The emission wavelength blueshift has been ensured by reducing both dots’ height and composition. A structure containing four vertically stacked height-engineered QDs have been fabricated, showing a room temperature broad emission band centered at 1.1 µm. The buried QD layers remain insensitive to the In-flush process of the subsequent layers, testifying the reliability of the process for broadband light sources required for high axial resolution OCT imaging. PMID:28773633

Small stack performance of intermediate temperature-operating solid oxide fuel cells using stainless steel interconnects and anode-supported single cell

NASA Astrophysics Data System (ADS)

Bae, Joongmyeon; Lim, Sungkwang; Jee, Hyunjin; Kim, Jung Hyun; Yoo, Young-Sung; Lee, Taehee

We are developing 1 kW class solid oxide fuel cell (SOFC) system for residential power generation (RPG) application supported by Korean Government. Anode-supported single cells with thin electrolyte layer of YSZ (yttria-stabilized zirconia) or ScSZ (scandia-stabilized zirconia) for intermediate temperature operation (650-750 °C), respectively, were fabricated and small stacks were built and evaluated. The LSCF/ScSZ/Ni-YSZ single cell showed performance of 543 mW cm -2 at 650 °C and 1680 mW cm -2 at 750 °C. The voltage of 15-cell stack based on 5 cm × 5 cm single cell (LSM/YSZ/Ni-YSZ) at 150 mW was 12.5 V in hydrogen as fuel of 120 sccm per cell at 750 °C and decreased to about 10.9 V at 500 h operation time. A 5-cell stack based on the LSCF/YSZ/FL/Ni-YSZ showed the maximum power density of 30 W, 25 W and 20 W at 750 °C, 700 °C and 650 °C, respectively. LSCF/ScSZ/Ni-YSZ-based stack showed better performance than LSCF/YSZ/Ni-YSZ stack from the experiment temperature range. I- V characteristics by using hydrogen gas and reformate gas of methane as fuel were investigated at 750 °C in LSCF/ScSZ/FL/Ni-YSZ-based 5-cell stack.

Gas dispersion concentration of trace inorganic contaminants from fuel gas and analysis using head-column field-amplified sample stacking capillary electrophoresis.

PubMed

Yang, Jianmin; Li, Hai-Fang; Li, Meilan; Lin, Jin-Ming

2012-08-21

The presence of inorganic elements in fuel gas generally accelerates the corrosion and depletion of materials used in the fuel gas industry, and even leads to serious accidents. For identification of existing trace inorganic contaminants in fuel gas in a portable way, a highly efficient gas-liquid sampling collection system based on gas dispersion concentration is introduced in this work. Using the constructed dual path gas-liquid collection setup, inorganic cations and anions were simultaneously collected from real liquefied petroleum gas (LPG) and analyzed by capillary electrophoresis (CE) with indirect UV absorbance detection. The head-column field-amplified sample stacking technique was applied to improve the detection limits to 2-25 ng mL(-1). The developed collection and analytical methods have successfully determined existing inorganic contaminants in a real LPG sample in the range of 4.59-138.69 μg m(-3). The recoveries of cations and anions with spiked LPG samples were between 83.98 and 105.63%, and the relative standard deviations (RSDs) were less than 7.19%.

METHODS FOR DETERMINING THE POLYCHLORINATED BIPHENYL EMISSIONS FROM INCINERATION AND CAPACITOR AND TRANSFORMER FILLING PLANTS

EPA Science Inventory

Described are methods to measure the polychlorinated biphenyl (PCB) emissions from the stacks of municipal waste, industrial waste, and sewage sludge incinerators and from capacitor and transformer filling plants. The PCB emissions from the incineration plants are collected by im...

40 CFR 49.125 - Rule for limiting the emissions of particulate matter.

Code of Federal Regulations, 2011 CFR

2011-07-01

... pollution sources? (1) Particulate matter emissions from a combustion source stack (except for wood-fired..., British thermal unit (Btu), coal, combustion source, distillate fuel oil, emission, fuel, fuel oil, gaseous fuel, heat input, incinerator, marine vessel, mobile sources, motor vehicle, nonroad engine...

Outflows in low-mass galaxies at z >1

NASA Astrophysics Data System (ADS)

Maseda, Michael V.; MUSE GTO Consortium

2017-03-01

Star formation histories of local dwarf galaxies, derived through resolved stellar populations, appear complex and varied. The general picture derived from hydrodynamical simulations is one of cold gas accretion and bursty star formation, followed by feedback from supernovae and winds that heat and eject the central gas reservoirs. This ejection halts star formation until the material cools and re-accretes, resulting in an episodic SFH, particularly at stellar masses below ~ 109 M⊙. Such feedback has often been cited as the driving force behind the observed slowly-rising rotation curves in local dwarfs, due to an under-density of dark matter compared to theoretical models, which is one of the primary challenges to LCDM cosmology. However, these events have not yet been directly observed at high-redshift. Recently, using HST imaging and grism spectroscopy, we have uncovered an abundant population of low-mass galaxies (M* < 109 M⊙) at z = 1 - 2 that are undergoing strong bursts of star formation, in agreement with the theoretical predictions. These Extreme Emission Line Galaxies, with high specific SFRs and shallow gravitational potential wells, are ideal places to test the theoretical prediction of strong feedback-driven outflows. Here we use deep MUSE spectroscopy to search these galaxies for signatures of outflowing material, namely kinematic offsets between absorption lines (in the restframe optical and UV), which trace cool gas, and the nebular emission lines, which define the systemic redshift of the galaxy. Although the EELGs are intrinsically very faint, stacked spectra reveal blueshifted velocity centroids for Fe II absorption, which is indicative of outflowing cold gas. This represents the first constraint on outflows in M* < 109 M⊙ galaxies at z = 1 - 2. These outflows should regulate the star formation histories of low-mass galaxies at early cosmic times and thus play a crucial role in galaxy growth and evolution.

Light breeze in the local Universe

NASA Astrophysics Data System (ADS)

Concas, A.; Popesso, P.; Brusa, M.; Mainieri, V.; Erfanianfar, G.; Morselli, L.

2017-10-01

We analyze a complete spectroscopic sample of galaxies ( 600 000) drawn from Sloan Digital Sky Survey (SDSS, DR7) to look for evidence of galactic winds in the local Universe. We focus on the shape of the [OIII]λ5007 emission line as a tracer of ionizing gas outflows. We stack our spectra in a fine grid of star formation rate (SFR) and stellar mass to analyze the dependence of winds on the position of galaxies in the SFR versus mass diagram. We do not find any significant evidence of broad and shifted [OIII]λ5007 emission line which we interpret as no evidence of outflowing ionized gas in the global population. We have also classified these galaxies as star-forming or AGN-dominated according to their position in the standard BPT diagram. We show how the average [OIII]λ5007 profile changes as a function of the nature of the dominant ionizing source. We find that in the star-forming dominated source the oxygen line is symmetric and governed by the gravitational potential well. The AGN or composite AGN/star-formation activity objects, in contrast, display a prominent and asymmetric profile that can be well described by a broad Gaussian component that is blue-shifted from a narrow symmetric core. In particular, we find that the blue wings of the average [OIII]λ5007 profiles are increasingly prominent in the LINERs and Seyfert galaxies. We conclude that, through the identification of strong bulk motion as traced by the warm ionized gas, in the low-redshift Universe, "pure" star-formation activity does not seem capable of driving ionized-gas outflows, while, the presence of optically selected AGN seems to play a primary role. We discuss the implications of these results for the role of the quenching mechanism in the present-day Universe.

Estimates of ground level TSP, SO sub 2 and HCI for a municipal waste incinerator to be located at Tynes Bay - Bermuda

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kent Simmons, J.A.; Knap, A.H.

1991-04-01

The computer model Industrial Source Complex Short Term (ISCST) was used to study the stack emissions from a refuse incinerator proposed for the inland of Bermuda. The model predicts that the highest ground level pollutant concentrations will occur near Prospect, 800 m to 1,000 m due south of the stack. The authors installed a portable laboratory and instruments at Prospect to begin making air quality baseline measurements. By comparing the model's estimates of the incinerator contribution to the background levels measured at the site they predicted that stack emissions would not cause an increase in TSP or SO{sub 2}. Themore » incinerator will be a significant source of HCI to Bermuda air with ambient levels approaching air quality guidelines.« less

Heating boilers in Krakow, Poland: Options for improving efficiency and reducing emissions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cyklis, P.; Kowalski, J.; Kroll, J.

1995-08-01

In Krakow, Poland, coal-fired boilers are used to heat single apartment buildings and local heating districts. The population includes 2,930 small, hand-fired boilers and 227 larger traveling grate stoker-fired boilers. These boilers are important contributors to air quality problems in Krakow, and an assessment of their efficiency and emissions characteristics was recently undertaken. For the larger, stoker-fired boilers, efficiency was measured using a stack-loss method. In addition to the normal baseline fuel, the effects of coal cleaning and grading were evaluated. Testing was done at two selected sites. Boiler efficiencies were found to be low--50% to 67%. These boilers operatemore » without combustion controls or instrumentation for flue gas analysis. As a result, excess air levels are very high--up to 400%--leading to poor performance. Emissions were found to be typical for boilers of this type. Using the improved fuels yields reductions in emissions and improvement in efficiency when combined with proper adjustments. In the case of the hand-fired boilers, one set of cast-iron boilers and one set of steel boilers were tested. Efficiency in this case was measured using an input-output method for sets of three boilers taken together as a system. Emissions from these boilers are lowest when low volatile fuels, such as coke or smokeless briquettes, are used.« less

Coordination-Directed Stacking and Aggregation-Induced Emission Enhancement of the Zn(II) Schiff Base Complex.

PubMed

Wang, Dan; Li, Shu-Mu; Zheng, Jian-Quan; Kong, Duan-Yang; Zheng, Xiang-Jun; Fang, De-Cai; Jin, Lin-Pei

2017-01-17

2-(Trityliminomethyl)-quinolin-8-ol (HL) and its Zn(II) complex were synthesized and characterized by single-crystal X-ray diffraction. HL is an unsymmetrical molecule and coordinated with Zn(II) ion to form ZnL 2 in the antiparallel-mode arrangement via Zn-O (hydroxyl group) and Zn-N (quinoline ring) of HL. A high degree of ZnL 2 molecules ordering stacking is formed by the coordination bonds and intermolecular π-π interactions, in which head-to-tail arrangement (J-mode stacking) for L - is found. HL is nonfluorescent and ZnL 2 is weakly fluorescent in THF. The fluorescence emission of ZnL 2 enhances in THF/H 2 O as H 2 O% (volume %) is above 60% and aggregates particles with several hundred nanometers are formed, which is confirmed by DLS data and TEM images. The J-aggregates stacking for L - in ZnL 2 results in aggregation-induced emission enhancement (AIEE) for ZnL 2 in THF/H 2 O. Theoretical computations based on B3LYP/6-31G(d, p) and TD-B3LYP/6-31G(d, p) methods were carried out. ESIPT is the supposed mechanism for fluorescent silence of HL, and fluorescence emission of ZnL 2 is attributed to the restriction of ESIPT process. The oscillator strength of ZnL 2 increases from 0.017 for monomer to 0.032 for trimer. It indicates that a high degree of ZnL 2 molecules ordering stacking in THF/H 2 O is of benefit to fluorescence enhancement. HL is an ESIPT-coupled AIEE chemosensor for Zn(II) with high selectivity and sensitivity in aqueous medium. HL can efficiently detect intracellular Zn(II) ions because of ESIPT-coupled AIEE property of ZnL 2 in mixed solvent.

Quasars Probing Quasars. IX. The Kinematics of the Circumgalactic Medium Surrounding z ∼ 2 Quasars

NASA Astrophysics Data System (ADS)

Lau, Marie Wingyee; Prochaska, J. Xavier; Hennawi, Joseph F.

2018-04-01

We examine the kinematics of the gas in the environments of galaxies hosting quasars at z ∼ 2. We employ 148 projected quasar pairs to study the circumgalactic gas of the foreground quasars in absorption. The sample selects foreground quasars with precise redshift measurements, using emission lines with precision ≲300 km s‑1 and average offsets from the systemic redshift ≲ | 100 {km} {{{s}}}-1| . We stack the background quasar spectra at the foreground quasar’s systemic redshift to study the mean absorption in C II, C IV, and Mg II. We find that the mean absorptions exhibit large velocity widths σv ≈ 300 km s‑1. Further, the mean absorptions appear to be asymmetric about the systemic redshifts. The mean absorption centroids exhibit small redshift relative to the systemic δv ≈ +200 km s‑1, with large intrinsic scatter in the centroid velocities of the individual absorption systems. We find the observed widths are consistent with gas in gravitational motion and Hubble flow. However, while the observation of large widths alone does not require galactic-scale outflows, the observed offsets suggest that the gas is on average outflowing from the galaxy. The observed offsets also suggest that the ionizing radiation from the foreground quasars is anisotropic and/or intermittent.

Driving force of stacking-fault formation in SiC p-i-n diodes.

PubMed

Ha, S; Skowronski, M; Sumakeris, J J; Paisley, M J; Das, M K

2004-04-30

The driving force of stacking-fault expansion in SiC p-i-n diodes was investigated using optical emission microscopy and transmission electron microscopy. The stacking-fault expansion and properties of the partial dislocations were inconsistent with any stress as the driving force. A thermodynamic free energy difference between the perfect and a faulted structure is suggested as a plausible driving force in the tested diodes, indicating that hexagonal polytypes of silicon carbide are metastable at room temperature.

Testing of a Shrouded, Short Mixing Stack Gas Eductor Model Using High Temperature Primary Flow.

DTIC Science & Technology

1982-10-01

problem but of less significance than the heated surfaces of shipboard structure. Various types of electronic equipments and sensors carried by a combatant...here was to validate current procedures by comparison with previous data it was not considered essential to rein- stall these sensors or duplicate...sec) 205 tABLE XIX Mixing Stack Temperatura Data, Model B Thermocouple Axial Mixing Stack Temperature _ mbjr Posii--- .. (I IF) . Uptake 180 850 950

Pollution Measuring System

NASA Technical Reports Server (NTRS)

1980-01-01

Research Ventures, Inc.'s visiplume is a portable, microprocessor-controlled air pollution monitor for measuring sulfur dioxide emissions from fossil fuel-fired power plants, and facilities that manufacture sulfuric acid. It observes smokestack plumes at a distance from the stack obviating the expense and difficulty of installing sample collectors in each stack and later analyzing the samples.

Reducing respiratory motion artifacts in positron emission tomography through retrospective stacking

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thorndyke, Brian; Schreibmann, Eduard; Koong, Albert

Respiratory motion artifacts in positron emission tomography (PET) imaging can alter lesion intensity profiles, and result in substantially reduced activity and contrast-to-noise ratios (CNRs). We propose a corrective algorithm, coined 'retrospective stacking' (RS), to restore image quality without requiring additional scan time. Retrospective stacking uses b-spline deformable image registration to combine amplitude-binned PET data along the entire respiratory cycle into a single respiratory end point. We applied the method to a phantom model consisting of a small, hot vial oscillating within a warm background, as well as to {sup 18}FDG-PET images of a pancreatic and a liver patient. Comparisons weremore » made using cross-section visualizations, activity profiles, and CNRs within the region of interest. Retrospective stacking was found to properly restore the lesion location and intensity profile in all cases. In addition, RS provided CNR improvements up to three-fold over gated images, and up to five-fold over ungated data. These phantom and patient studies demonstrate that RS can correct for lesion motion and deformation, while substantially improving tumor visibility and background noise.« less

Remote control flare stack igniter for combustible gases

NASA Technical Reports Server (NTRS)

Ray, W. L.

1972-01-01

Device has been designed and developed for igniting nonrecoverable combustible gases and sustaining combustion of gases evolving from various gas vent stacks. Igniter is superior to existing systems because of simplicity of operation, low cost fabrication, installation, operational and maintainability features, and excellent reliability in all phases of required operations.

40 CFR 63.11466 - What are the performance test requirements for new and existing sources?

Code of Federal Regulations, 2010 CFR

2010-07-01

... (Appendix A-1) to select sampling port locations and the number of traverse points in each stack or duct... of the stack gas. (iii) Method 3, 3A, or 3B (Appendix A-2) to determine the dry molecular weight of...

Nitride-based stacked laser diodes with a tunnel junction

NASA Astrophysics Data System (ADS)

Okawara, Satoru; Aoki, Yuta; Kuwabara, Masakazu; Takagi, Yasufumi; Maeda, Junya; Yoshida, Harumasa

2018-01-01

We report on nitride-based two-stack laser diodes with a tunnel junction for the first time. The stacked laser diode was monolithically grown by metalorganic vapor phase epitaxy. It was confirmed that the two-stack InGaN/GaN multiple-quantum-well laser diode with an emission wavelength of 394 nm exhibited laser oscillation up to a peak output power of over 10 W in the pulsed current mode. The upper and lower emitters of the device were capable of lasing at different threshold currents of 2.4 and 5.2 A with different slope efficiencies of 0.8 and 0.3 W/A, respectively.

Gas block mechanism for water removal in fuel cells

DOEpatents

Issacci, Farrokh; Rehg, Timothy J.

2004-02-03

The present invention is directed to apparatus and method for cathode-side disposal of water in an electrochemical fuel cell. There is a cathode plate. Within a surface of the plate is a flow field comprised of interdigitated channels. During operation of the fuel cell, cathode gas flows by convection through a gas diffusion layer above the flow field. Positioned at points adjacent to the flow field are one or more porous gas block mediums that have pores sized such that water is sipped off to the outside of the flow field by capillary flow and cathode gas is blocked from flowing through the medium. On the other surface of the plate is a channel in fluid communication with each porous gas block mediums. The method for water disposal in a fuel cell comprises installing the cathode plate assemblies at the cathode sides of the stack of fuel cells and manifolding the single water channel of each of the cathode plate assemblies to the coolant flow that feeds coolant plates in the stack.

Study of Stack Emissions from Coast Guard Cutters

DOT National Transportation Integrated Search

1973-09-01

The gaseous and particulate emissions from 14 cutters and boats in the First Coast Guard District have been measured under typical operating conditions. These measurements were performed on 57 diesel engines and boilers configured as main propulsion ...

Method for monitoring stack gases for uranium activity

DOEpatents

Beverly, C.R.; Ernstberger, E.G.

1985-07-03

A method for monitoring the stack gases of a purge cascade of gaseous diffusion plant for uranium activity. A sample stream is taken from the stack gases and contacted with a volume of moisture-laden air for converting trace levels of uranium hexafluoride, if any, in the stack gases into particulate uranyl fluoride. A continuous strip of filter paper from a supply roll is passed through this sampling stream to intercept and gather any uranyl fluoride in the sampling stream. This filter paper is then passed by an alpha scintillation counting device where any radioactivity on the filter paper is sensed so as to provide a continuous monitoring of the gas stream for activity indicative of the uranium content in the stack gases. 1 fig.

Method for monitoring stack gases for uranium activity

DOEpatents

Beverly, Claude R.; Ernstberger, Harold G.

1988-01-01

A method for monitoring the stack gases of a purge cascade of a gaseous diffusion plant for uranium activity. A sample stream is taken from the stack gases and contacted with a volume of moisture-laden air for converting trace levels of uranium hexafluoride, if any, in the stack gases into particulate uranyl fluoride. A continuous strip of filter paper from a supply roll is passed through this sampling stream to intercept and gather any uranyl fluoride in the sampling stream. This filter paper is then passed by an alpha scintillation counting device where any radioactivity on the filter paper is sensed so as to provide a continuous monitoring of the gas stream for activity indicative of the uranium content in the stack gases.

Simultaneous treatment of SO2 containing stack gases and waste water

NASA Technical Reports Server (NTRS)

Poradek, J. C.; Collins, D. D. (Inventor)

1978-01-01

A process for simultaneously removing sulfur dioxide from stack gases and the like and purifying waste water such as derived from domestic sewage is described. A portion of the gas stream and a portion of the waste water, the latter containing dissolved iron and having an acidic pH, are contacted in a closed loop gas-liquid scrubbing zone to effect absorption of the sulfur dioxide into the waste water. A second portion of the gas stream and a second portion of the waste water are controlled in an open loop gas-liquid scrubbing zone. The second portion of the waste water contains a lesser amount of iron than the first portion of the waste water. Contacting in the openloop scrubbing zone is sufficient to acidify the waste water which is then treated to remove solids originally present.

40 CFR 60.52c - Emission limits.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Emission limits. 60.52c Section 60.52c... Incinerators for Which Construction is Commenced After June 20, 1996 § 60.52c Emission limits. (a) On and after... that contain stack emissions in excess of the limits presented in Table 1A to this subpart. (2) From an...

Demonstration of fuel switching on oceangoing vessels in the Gulf of Mexico.

PubMed

Browning, Louis; Hartley, Seth; Bandemehr, Angela; Gathright, Kenneth; Miller, Wayne

2012-09-01

Switching fuels from high-sulfur heavy fuel oils (HFO) to lower sulfur marine gas oils (MGO) on an oceangoing vessel (OGV) can substantially reduce both PM and SO(x) ship stack emissions, potentially resulting in significant human health and environmental benefits in Gulf of Mexico port communities. The International Maritime Organization (IMO) established an emission control area (ECA) within 200 nautical miles of the US. and Canadian coastlines and French territories off the coast of Canada with lower fuel sulfur standards effective beginning August 2012, where OGVs will need to switch from HFO to MGO. However some operators and other stakeholders, particularly in the Gulf of Mexico, may be unfamiliar with the benefits and requirements and ship operators may be concerned over potential implications for cost and operations. This first-ever US. Environmental Protection Agency (EPA)-sponsored fuel switching demonstration in the Gulf of Mexico was initiated to showcase the environmental and health benefits of as well as operational issues associated with, fuel switching through the following activities: (1) Fuel switching was conducted on typical container ships operating the Gulf of Mexico, as routine fuel switching has been demonstrated in California in recent years. Two vessels were employed in the demonstration: the Maersk Roubaix, which switched fuels entering Port of Houston, TX, and the Port of Progreso, Mexico, and the Hamburg Süd vessel Cap San Lorenzo, which switched fuels entering the Port of Houston and the Mexican Ports of Veracruz and Altamira. Operational and cost aspects were also noted. (2) Emissions reductions were quantified through both a calculation approach based on fuel use of the Maersk Line vessel Roubaix and in-stack monitoring of emissions from the Hamburg Süd Cap San Lorenzo. Pollutant emissions including PM, SO(x), NO(x), and PM component speciation were sampled during use of both fuels. These observations showed reductions (1-6%) in NO(x) and substantial reductions in PM (50-70%) and SO(x) (> 99%) depending on engine and load. (3) Emission inventories at three ports were calculated. (4) Potential health and environmental benefits to communities and ecosystems in the Gulf of Mexico were estimated through screening-level modeling of air dispersion and atmospheric deposition of ship emissions at the Port of Veracruz to indicate the substantial reductions available through fuel switching. The United States and Canada have recently adopted a North American Emission Control Area that will require a shift from high-sulfur to low-sulfur fuels in the marine transportation sector. Cleaner fuels are expected to reduce sulfur and particulate emissions. This paper verifies the feasibility of such switching operations, the potential to reduce emissions if extended to the Gulf of Mexico, and the associated environmental impacts of these emission reductions inland and to sensitive ecosystems.

Gaseous and particulate emissions from thermal power plants operating on different technologies.

PubMed

Athar, Makshoof; Ali, Mahboob; Khan, Misbahul Ain

2010-07-01

This paper presents the assessment of gaseous and particulate emissions from thermal power plants operating on different combustion technologies. Four thermal power plants operating on heavy furnace oil were selected for the study, among which three were based on diesel engine technology, while the fourth plant was based on oil-fired steam turbine technology. The stack emissions were monitored for critical air pollutants carbon monoxide, carbon dioxide, oxides of nitrogen, sulfur dioxide, particulate matter, lead, and mercury. The pollutant emissions were measured at optimum load conditions for a period of 6 months with an interval of 1 month. The results of stack emissions were compared with National Environmental Quality Standards of Pakistan and World Bank guidelines for thermal power plants, and few parameters were found higher than the permissible limits of emissions. It was observed that the emissions carbon monoxide, oxides of nitrogen, and particulate matters from diesel engine-based power plants were comparatively higher than the turbine-based power plants. The emissions of sulfur dioxide were high in all the plants, even the plants with different technologies, which was mainly due to high sulfur contents in fuel.

Smooth H I Low Column Density Outskirts in Nearby Galaxies

NASA Astrophysics Data System (ADS)

Ianjamasimanana, R.; Walter, Fabian; de Blok, W. J. G.; Heald, George H.; Brinks, Elias

2018-06-01

The low column density gas at the outskirts of galaxies as traced by the 21 cm hydrogen line emission (H I) represents the interface between galaxies and the intergalactic medium, i.e., where galaxies are believed to get their supply of gas to fuel future episodes of star formation. Photoionization models predict a break in the radial profiles of H I at a column density of ∼5 × 1019 cm‑2 due to the lack of self-shielding against extragalactic ionizing photons. To investigate the prevalence of such breaks in galactic disks and to characterize what determines the potential edge of the H I disks, we study the azimuthally averaged H I column density profiles of 17 nearby galaxies from the H I Nearby Galaxy Survey and supplemented in two cases with published Hydrogen Accretion in LOcal GAlaxieS data. To detect potential faint H I emission that would otherwise be undetected using conventional moment map analysis, we line up individual profiles to the same reference velocity and average them azimuthally to derive stacked radial profiles. To do so, we use model velocity fields created from a simple extrapolation of the rotation curves to align the profiles in velocity at radii beyond the extent probed with the sensitivity of traditional integrated H I maps. With this method, we improve our sensitivity to outer-disk H I emission by up to an order of magnitude. Except for a few disturbed galaxies, none show evidence of a sudden change in the slope of the H I radial profiles: the alleged signature of ionization by the extragalactic background.

Updated (BP3) Technical and Economic Feasibility Study - Electrochemical Membrane for Carbon Dioxide Capture and Power Generation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ghezel-Ayagh, Hossein

This topical report summarizes the results of an updated Technical & Economic Feasibility Study (T&EFS) which was conducted in Budget Period 3 of the project to evaluate the performance and cost of the Electrochemical Membrane (ECM)-based CO 2 capture system. The ECM technology is derived from commercially available inorganic membranes; the same used in FuelCell Energy’s commercial fuel cell power plants and sold under the trade name Direct FuelCell® (DFC®). The ECM stacks are utilized in the Combined Electric Power (generation) And Carbon dioxide Separation (CEPACS) systems which can be deployed as add-ons to conventional power plants (Pulverized Coal, Combinedmore » Cycle, etc.) or industrial facilities to simultaneously produce power while capturing >90% of the CO 2 from the flue gas. In this study, an ECM-based CEPACS plant was designed to capture and compress >90% of the CO 2 (for sequestration or beneficial use) from the flue gas of a reference 550 MW (nominal, net AC) Pulverized Coal (PC) Rankine Cycle (Subcritical steam) power plant. ECM performance was updated based on bench scale ECM stack test results. The system process simulations were performed to generate the CEPACS plant performance estimates. The performance assessment included estimation of the parasitic power consumption for CO 2 capture and compression, and the efficiency impact on the PC plant. While the ECM-based CEPACS system for the 550 MW PC plant captures 90% of CO 2 from the flue gas, it generates additional (net AC) power after compensating for the auxiliary power requirements of CO 2 capture and compression. An equipment list, ECM stacks packaging design, and CEPACS plant layout were developed to facilitate the economic analysis. Vendor quotes were also solicited. The economic feasibility study included estimation of CEPACS plant capital cost, cost of electricity (COE) analyses and estimation of cost per ton of CO 2 captured. The incremental COE for the ECM-based CO 2 capture is expected to meet U.S. DOE’s target of 35%. This study has indicated that CEPACS systems offer significant benefits with respect to cost, performance, water consumption and emissions to environment. The realization of these benefits will provide a single solution to carbon dioxide capture in addition to meeting the increasing demand for electricity.« less

Updated (BP3) Technical and Economic Feasibility Study - Electrochemical Membrane for Carbon Dioxide Capture and Power Generation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ghezel-Ayagh, Hossein

This topical report summarizes the results of an updated Technical & Economic Feasibility Study (T&EFS) which was conducted in Budget Period 3 of the project to evaluate the performance and cost of the Electrochemical Membrane (ECM)-based CO2 capture system. The ECM technology is derived from commercially available inorganic membranes; the same used in FuelCell Energy’s commercial fuel cell power plants and sold under the trade name Direct FuelCell® (DFC®). The ECM stacks are utilized in the Combined Electric Power (generation) And Carbon dioxide Separation (CEPACS) systems which can be deployed as add-ons to conventional power plants (Pulverized Coal, Combined Cycle,more » etc.) or industrial facilities to simultaneously produce power while capturing >90% of the CO2 from the flue gas. In this study, an ECM-based CEPACS plant was designed to capture and compress >90% of the CO2 (for sequestration or beneficial use) from the flue gas of a reference 550 MW (nominal, net AC) Pulverized Coal (PC) Rankine Cycle (Subcritical steam) power plant. ECM performance was updated based on bench scale ECM stack test results. The system process simulations were performed to generate the CEPACS plant performance estimates. The performance assessment included estimation of the parasitic power consumption for CO2 capture and compression, and the efficiency impact on the PC plant. While the ECM-based CEPACS system for the 550 MW PC plant captures 90% of CO2 from the flue gas, it generates additional (net AC) power after compensating for the auxiliary power requirements of CO2 capture and compression. An equipment list, ECM stacks packaging design, and CEPACS plant layout were developed to facilitate the economic analysis. Vendor quotes were also solicited. The economic feasibility study included estimation of CEPACS plant capital cost, cost of electricity (COE) analyses and estimation of cost per ton of CO2 captured. The incremental COE for the ECM-based CO2 capture is expected to meet U.S. DOE’s target of 35%. This study has indicated that CEPACS systems offer significant benefits with respect to cost, performance, water consumption and emissions to environment. The realization of these benefits will provide a single solution to carbon dioxide capture in addition to meeting the increasing demand for electricity.« less

Planning studies for measurement of chemical emissions in stack gases of coal-fired power plants. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barrett, W.J.; Gooch, J.P.; Dahlin, R.S.

1983-03-01

Airborne emissions from coal-fired power plants consist of sulfur, nitrogen, and carbon oxides, as well as traces of certain metals or elements, radionuclides, and organic compounds that have the potential of producing adverse health effects if inhaled. To assess this potential toxicity, samples must be obtained and characterized on the basis of quantity, their chemistry, and toxicity. Sample representativeness and use of proper chemical-biological procedures are the critical for providing input into current research directed toward source apportionment and inhalation toxicology. Obtaining a valid stack sample (gases and particles) from each of more than 1500 US coal-fired power plant ismore » not practical; consequently 33 plants have been selected, taking into account plant design and operating parameters that can affect the characteristics of stack chemical emissions. Since such a program has an estimated cost of $20 million over many years, it is recommended that the initial program consists of sampling only six of the 33 units, selected with EPRI guidance, at an estimated cost of $3.5 million over a 30 month period. The plan is directed at in-stack sampling, plume and atmospheric transformations being beyond the project scope. Various stack sampling methods are considered. For particles, a modified SASS train seems best, and for gases, either resin traps or impingers are probably best. Artifact formation must be minimized. Chemical analysis procedures are to be guided by the known toxicity of species present. Procedures are outlined for organics (volatile and nonvolatile), trace elements, inorganics, and gases. Bioassay methods are restricted to in vitro, subdivided into those assays that detect genetic and direct cellular toxicity.« less

Sampling for Air Chemical Emissions from the Life Sciences Laboratory II

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ballinger, Marcel Y.; Lindberg, Michael J.

Sampling for air chemical emissions from the Life Science Laboratory II (LSL-II) ventilation stack was performed in an effort to determine potential exposure of maintenance staff to laboratory exhaust on the building roof. The concern about worker exposure was raised in December 2015 and several activities were performed to assist in estimating exposure concentrations. Data quality objectives were developed to determine the need for and scope and parameters of a sampling campaign to measure chemical emissions from research and development activities to the outside air. The activities provided data on temporal variation of air chemical concentrations and a basis formore » evaluating calculated emissions. Sampling for air chemical emissions was performed in the LSL-II ventilation stack over the 6-week period from July 26 to September 1, 2016. A total of 12 sampling events were carried out using 16 sample media. Resulting analysis provided concentration data on 49 analytes. All results were below occupational exposure limits and most results were below detection limits. When compared to calculated emissions, only 5 of the 49 chemicals had measured concentrations greater than predicted. This sampling effort will inform other study components to develop a more complete picture of a worker’s potential exposure from LSL-II rooftop activities. Mixing studies were conducted to inform spatial variation in concentrations at other rooftop locations and can be used in conjunction with these results to provide temporal variations in concentrations for estimating the potential exposure to workers working in and around the LSL-II stack.« less

Fermi LAT Stacking Analysis of Swift Localized GRBs

DOE PAGES

Ackermann, M.; Ajello, M.; Anderson, B.; ...

2016-05-05

In this paper, we perform a comprehensive stacking analysis of data collected by the Fermi Large Area Telescope (LAT) of γ-ray bursts (GRBs) localized by the Swift spacecraft, which were not detected by the LAT but which fell within the instrument's field of view at the time of trigger. We examine a total of 79 GRBs by comparing the observed counts over a range of time intervals to that expected from designated background orbits, as well as by using a joint likelihood technique to model the expected distribution of stacked counts. We find strong evidence for subthreshold emission at MeVmore » to GeV energies using both techniques. This observed excess is detected during intervals that include and exceed the durations typically characterizing the prompt emission observed at keV energies and lasts at least 2700 s after the co-aligned burst trigger. By utilizing a novel cumulative likelihood analysis, we find that although a burst's prompt γ-ray and afterglow X-ray flux both correlate with the strength of the subthreshold emission, the X-ray afterglow flux measured by Swift's X-ray Telescope at 11 hr post trigger correlates far more significantly. Overall, the extended nature of the subthreshold emission and its connection to the burst's afterglow brightness lend further support to the external forward shock origin of the late-time emission detected by the LAT. Finally, these results suggest that the extended high-energy emission observed by the LAT may be a relatively common feature but remains undetected in a majority of bursts owing to instrumental threshold effects.« less

Develop and test fuel cell powered on-site integrated total energy system

NASA Technical Reports Server (NTRS)

Kaufman, A.; Feigenbaum, H.; Wang, C. L.; Werth, J.; Whelan, J. A.

1983-01-01

Test results are presented for a 24 cell, two sq ft (4kW) stack. This stack is a precursor to a 25kW stack that is a key milestone. Results are discussed in terms of cell performance, electrolyte management, thermal management, and reactant gas manifolding. The results obtained in preliminary testing of a 50kW methanol processing subsystem are discussed. Subcontracting activities involving application analysis for fuel cell on site integrated energy systems are updated.

Stack Flow Rate Changes and the ANSI/N13.1-1999 Qualification Criteria: Application to the Hanford Canister Storage Building Stack

DOE Office of Scientific and Technical Information (OSTI.GOV)

Flaherty, Julia E.; Glissmeyer, John A.

2016-02-29

The Canister Storage Building (CSB), located in the 200-East Area of the Hanford Site, is a 42,000 square foot facility used to store spent nuclear fuel from past activities at the Hanford Site. Because the facility has the potential to emit radionuclides into the environment, its ventilation exhaust stack has been equipped with an air monitoring system. Subpart H of the National Emissions Standards for Hazardous Air Pollutants requires that a sampling probe be located in the exhaust stack in accordance with criteria established by the American National Standards Institute/Health Physics Society Standard N13.1-1999, Sampling and Monitoring Releases of Airbornemore » Radioactive Substances from the Stack and Ducts of Nuclear Facilities.« less

Subtask 4.27 - Evaluation of the Multielement Sorbent Trap (MEST) Method at an Illinois Coal-Fired Plant

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pavlish, John; Thompson, Jeffrey; Dunham, Grant

2014-09-30

Owners of fossil fuel-fired power plants face the challenge of measuring stack emissions of trace metals and acid gases at much lower levels than in the past as a result of increasingly stringent regulations. In the United States, the current reference methods for trace metals and halogens are wet-chemistry methods, U.S. Environmental Protection Agency (EPA) Methods 29 and 26 or 26A, respectively. As a possible alternative to the EPA methods, the Energy & Environmental Research Center (EERC) has developed a novel multielement sorbent trap (MEST) method to be used to sample for trace elements and/or halogens. Sorbent traps offer amore » potentially advantageous alternative to the existing sampling methods, as they are simpler to use and do not require expensive, breakable glassware or handling and shipping of hazardous reagents. Field tests comparing two sorbent trap applications (MEST-H for hydrochloric acid and MEST-M for trace metals) with the reference methods were conducted at two power plant units fueled by Illinois Basin bituminous coal. For hydrochloric acid, MEST measured concentrations comparable to EPA Method 26A at two power plant units, one with and one without a wet flue gas desulfurization scrubber. MEST-H provided lower detection limits for hydrochloric acid than the reference method. Results from a dry stack unit had better comparability between methods than results from a wet stack unit. This result was attributed to the very low emissions in the latter unit, as well as the difficulty of sampling in a saturated flue gas. Based on these results, the MEST-H sorbent traps appear to be a good candidate to serve as an alternative to Method 26A (or 26). For metals, the MEST trap gave lower detection limits compared to EPA Method 29 and produced comparable data for antimony, arsenic, beryllium, cobalt, manganese, selenium, and mercury for most test runs. However, the sorbent material produced elevated blanks for cadmium, nickel, lead, and chromium at levels that would interfere with accurate measurement at U.S. hazardous air pollutant emission limits for existing coal-fired power plant units. Longer sampling times employed during this test program did appear to improve comparative results for these metals. Although the sorbent contribution to the sample was reduced through improved trap design, additional research is still needed to explore lower-background materials before the MEST-M application can be considered as a potential alternative method for all of the trace metals. This subtask was funded through the EERC–U.S. Department of Energy Joint Program on Research and Development for Fossil Energy-Related Resources Cooperative Agreement No. DE-FC26-08NT43291. Nonfederal funding was provided by the Electric Power Research Institute, the Illinois Clean Coal Institute, Southern Illinois Power Company, and the Center for Air Toxic Metals Affiliates Program.« less

77 FR 555 - National Emissions Standards for Hazardous Air Pollutants From Secondary Lead Smelting

Federal Register 2010, 2011, 2012, 2013, 2014

2012-01-05

..., stack, storage, or fugitive emissions point; and/or are design, equipment, work practice, or operational... procedures designed to minimize emissions of THC for each start-up and shutdown scenario anticipated for all... designed and maintained can sometimes fail and that such failure can sometimes cause an exceedance of the...

Battery condenser system total particulate emission factors and rates for cotton gins

USDA-ARS?s Scientific Manuscript database

This manuscript is part of a series of manuscripts that characterize cotton gin emissions from the standpoint of stack sampling. The impetus behind this project was the urgent need to collect additional cotton gin emissions data to address current regulatory issues. A key component of this study was...

Battery condenser system PM10 emission factors and rates for cotton gins

USDA-ARS?s Scientific Manuscript database

This manuscript is part of a series of manuscripts that to characterize cotton gin emissions from the standpoint of stack sampling. The impetus behind this project was the urgent need to collect additional cotton gin emissions data to address current regulatory issues. A key component of this study ...

Battery condenser system total particulate emission factors and rates for cotton gins: Method 17

USDA-ARS?s Scientific Manuscript database

This manuscript is part of a series of manuscripts that characterize cotton gin emissions from the standpoint of stack sampling. The impetus behind this project was the urgent need to collect additional cotton gin emissions data to address current regulatory issues. A key component of this study was...

Acoustic streaming related to minor loss phenomenon in differentially heated elements of thermoacoustic devices

NASA Astrophysics Data System (ADS)

Mironov, Mikhail; Gusev, Vitalyi; Auregan, Yves; Lotton, Pierrick; Bruneau, Michel; Piatakov, Pavel

2002-08-01

It is demonstrated that the differentially heated stack, the heart of all thermoacoustic devices, provides a source of streaming additional to those associated with Reynolds stresses in quasi-unidirectional gas flow. This source of streaming is related to temperature-induced asymmetry in the generation of vortices and turbulence near the stack ends. The asymmetry of the hydrodynamic effects in an otherwise geometrically symmetric stack is due to the temperature difference between stack ends. The proposed mechanism of streaming excitation in annular thermoacoustic devices operates even in the absence of thermo-viscous interaction of sound waves with resonator walls. copyright 2002 Acoustical Society of America.

40 CFR Table 1 to Subpart Ttttt of... - Emission Limits

Code of Federal Regulations, 2013 CFR

2013-07-01

... the following . . . 1. Each spray dryer stack a. You must not cause to be discharged to the atmosphere... discharged to the atmosphere any gases that contain hydrochloric acid in excess of 200 lbs/hr. 2. Each magnesium chloride storage bins scrubber stack a. You must not cause to be discharged to the atmosphere any...

40 CFR Table 1 to Subpart Ttttt of... - Emission Limits

Code of Federal Regulations, 2014 CFR

2014-07-01

... the following . . . 1. Each spray dryer stack a. You must not cause to be discharged to the atmosphere... discharged to the atmosphere any gases that contain hydrochloric acid in excess of 200 lbs/hr. 2. Each magnesium chloride storage bins scrubber stack a. You must not cause to be discharged to the atmosphere any...

40 CFR Table 1 to Subpart Ttttt of... - Emission Limits

Code of Federal Regulations, 2011 CFR

2011-07-01

... the following . . . 1. Each spray dryer stack a. You must not cause to be discharged to the atmosphere... discharged to the atmosphere any gases that contain hydrochloric acid in excess of 200 lbs/hr. 2. Each magnesium chloride storage bins scrubber stack a. You must not cause to be discharged to the atmosphere any...

40 CFR Table 1 to Subpart Ttttt of... - Emission Limits

Code of Federal Regulations, 2012 CFR

2012-07-01

... the following . . . 1. Each spray dryer stack a. You must not cause to be discharged to the atmosphere... discharged to the atmosphere any gases that contain hydrochloric acid in excess of 200 lbs/hr. 2. Each magnesium chloride storage bins scrubber stack a. You must not cause to be discharged to the atmosphere any...

40 CFR Table 1 to Subpart Ttttt of... - Emission Limits

Code of Federal Regulations, 2010 CFR

2010-07-01

... the following . . . 1. Each spray dryer stack a. You must not cause to be discharged to the atmosphere... discharged to the atmosphere any gases that contain hydrochloric acid in excess of 200 lbs/hr. 2. Each magnesium chloride storage bins scrubber stack a. You must not cause to be discharged to the atmosphere any...

40 CFR 60.1790 - What test methods must I use to stack test?

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 6 2011-07-01 2011-07-01 false What test methods must I use to stack test? 60.1790 Section 60.1790 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES Emission Guidelines and Compliance Times for Small Municipal Waste...

40 CFR 60.1790 - What test methods must I use to stack test?

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 7 2012-07-01 2012-07-01 false What test methods must I use to stack test? 60.1790 Section 60.1790 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES Emission Guidelines and Compliance Times for Small Municipal Waste...

40 CFR 60.1790 - What test methods must I use to stack test?

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 7 2014-07-01 2014-07-01 false What test methods must I use to stack test? 60.1790 Section 60.1790 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES Emission Guidelines and Compliance Times for Small Municipal Waste...

40 CFR 60.1790 - What test methods must I use to stack test?

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 7 2013-07-01 2013-07-01 false What test methods must I use to stack test? 60.1790 Section 60.1790 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES Emission Guidelines and Compliance Times for Small Municipal Waste...

Air pollution and dry deposition of nitrogen and sulphur in the AOSR estimated using passive samplers

Treesearch

Yu-Mei Hsu; Andrzej Bytnerowicz

2015-01-01

NO2 and SO2 are the primary pollutants produced by industrial facilities of the Athabasca Oil sand Region (AOSR), Alberta, Canada. The major emission sources are the upgrader stacks for SO2 and stacks, mine fleets and vehicles for NO2. After emitting from the sources, NO

Stacking Oxygen-Separation Cells

NASA Technical Reports Server (NTRS)

Schroeder, James E.

1991-01-01

Simplified configuration and procedure developed for assembly of stacks of solid-electrolyte cells separating oxygen from air electrochemically. Reduces number of components and thus reduces probability of such failures as gas leaks, breakdown of sensitive parts, and electrical open or short circuits. Previous, more complicated version of cell described in "Improved Zirconia Oxygen-Separation Cell" (NPO-16161).

40 CFR Table I-17 to Subpart I of... - Expected and Possible By-Products for Electronics Manufacturinglg

Code of Federal Regulations, 2014 CFR

2014-07-01

... Electronics Manufacturinglg I Table I-17 to Subpart I of Part 98 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Electronics... for Electronics Manufacturinglg For each stack system for which you use the “stack test method” to...

Africa burning: A thematic analysis of the Southern African Regional Science Initiative (SAFARI 2000)

NASA Astrophysics Data System (ADS)

Swap, Robert J.; Annegarn, Harold J.; Suttles, J. Timothy; King, Michael D.; Platnick, Steven; Privette, Jeffrey L.; Scholes, Robert J.

2003-07-01

The Southern African Regional Science Initiative (SAFARI 2000) was a major surface, airborne, and spaceborne field campaign carried out in southern Africa in 2000 and 2001 that addressed a broad range of phenomena related to land-atmosphere interactions and the biogeochemical functioning of the southern African system. This paper presents a thematic analysis and integration of the Journal of Geophysical Research SAFARI 2000 Special Issue, presenting key findings of an intensive field campaign over southern Africa in August and September of 2000. The integrating themes deal with surface emissions characterization; airborne characterizations of aerosols and trace gases; regional haze and trace gas characterization; and radiant measurements by surface, aircraft, and remote sensing platforms. Enhanced regional fuel loads associated with the moist La Niña phase of the El Niño-Southern Oscillation (ENSO) cycle produced above average biomass burning emissions, which consequently dominated all other aerosol and trace gas emissions during the dry season. Southward transport of a broad plume of smoke originating in equatorial Africa and exiting off the east coast toward the Indian Ocean (the river of smoke) is attributed to unusual synoptic airflows associated the ENSO phase. New and revised biogenic and pyrogenic emission factors are reported, including a number of previously unreported oxygenated organic compounds and inorganic compounds from biomass combustion. Emission factors are scaled up to regional emission surfaces for biogenic species utilizing species specific and light-dependent emission factors. Fire scar estimates reveal contradictory information on the timing of the peak and extent of the biomass-burning season. Integrated tall stack coordinated measurements (between ground, airborne and remotely sensing platforms) of upwelling and downwelling radiation in massive thick aerosol layers covering much of southern Africa yield consistent estimates of large negative forcing for both surface and top of atmosphere radiative forcing. Radiation calculations are supported by novel information on chemical speciation and internal aerosol particle structure. The overall conclusion is that SAFARI 2000, as an integrating theme, has been able to give significant new insights into the regional scale biogeochemical cycling of southern Africa and contributed in important ways to the validation of remote sensing instruments on board the NASA Terra spacecraft.

PRELIMINARY ENVIRONMENTAL, HEALTH AND SAFETY RISK ASSESSMENT ON THE INTEGRATION OF A PROCESS UTILIZING LOW-ENERGY SOLVENTS FOR CARBON DIOXIDE CAPTURE ENABLED BY A COMBINATION OF ENZYMES AND VACUUM REGENERATION WITH A SUBCRITICAL PC POWER PLANT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fitzgerald, David; Vidal, Rafael; Russell, Tania

2014-12-31

The results of the preliminary environmental, health and safety (EH&S) risk assessment for an enzyme-activated potassium carbonate (K2CO3) solution post-combustion CO2 capture (PCC) plant, integrated with a subcritical pulverized coal (PC) power plant, are presented. The expected emissions during normal steady-state operation have been estimated utilizing models of the PCC plant developed in AspenTech’s AspenPlus® software, bench scale test results from the University of Kentucky, and industrial experience of emission results from a slipstream PCC plant utilizing amine based solvents. A review of all potential emission species and their sources was undertaken that identified two credible emission sources, the absorbermore » off-gas that is vented to atmosphere via a stack and the waste removed from the PCC plant in the centrifuge used to reclaim enzyme and solvent. The conditions and compositions of the emissions were calculated and the potential EH&S effects were considered as well as legislative compliance requirements. Potential mitigation methods for emissions during normal operation have been proposed and solutions to mitigate uncontrolled releases of species have been considered. The potential emissions were found to pose no significant EH&S concerns and were compliant with the Federal legislation reviewed. The limitations in predicting full scale plant performance from bench scale tests have been noted and further work on a larger scale test unit is recommended to reduce the level of uncertainty.« less

Comparative Analysis of Carbon Dioxide Emissions across Large Urban Areas in the U.S.

NASA Astrophysics Data System (ADS)

Patarasuk, R.; Gurney, K. R.; O'Keeffe, D.; Song, Y.; Rao, P.; Huang, J.; Razlivanov, I. N.

2014-12-01

Carbon dioxide (CO2) emissions from fossil fuel combustion represents the single largest net annual flux of carbon into the atmosphere. Even though urban areas cover only 2% of the earth's surface, they contribute about 70% of global carbon emissions. We aim to conduct a comparative analysis of fossil fuel CO2 (FFCO2) emissions in three large urban areas across different regions in the U.S. based on our spatially-explicit Hestia approach, called the 'Hestia Project'. This research effort is the first to use bottom-up methods to quantify all FFCO2 emissions down to the scale of individual buildings, road segments, and industrial/electricity production facilities on an hourly basis for an entire urban landscape. The Hestia method relies on a large swath of input data such as criteria pollutant emissions reporting, stack monitoring, census data, tax assessor parcel data and traffic monitoring. The urban areas quantified with the Hestia approach include Indianapolis, Salt Lake City, and the Los Angeles Basin (encompassing over 80 cities). A comparative analysis will provide a better understanding of how and why FFCO2 emissions differ across time and space. We examine various factors such as heating/cooling degree days, population, GDP, industrial profile and building age. The study seeks to answer the following questions: 1) How and why do FFCO2 differ across the cities/regions? 2) What drives the different temporal profile of urban emissions? and 3) How do these vary across and within the urban landscape? The results from the study will benefit city planners and other stakeholders in managing urban development and greenhouse gas emissions mitigation.

Wind Tunnel Model Study of the Hot Exhaust Plume from the Compressor Research Facility at Wright-Patterson Air Force Base, Ohio

DTIC Science & Technology

1977-10-01

PLUME FROM THE COMPRESSOR JtESEARCHJAC ILITY AT WRIGHT- /ATTERSON AIR FORCE JBASE, OHIO , r= mrm (.) Gary R./Ludwig 9. PERFORMING ORGANIZATION NAME... ms Mass flux of stack exhaust gas (slugs/sec) nrtfl Mass flux of ambient air and stack exhaust gas mixture st plume cross-section A (slugs/sec...the horizontal momentum flux in the ambient wind be the same in the model as it is in full-scale. /»» Ms M i a. ’ ro P>"S P*» + ’f (3) where 0

Generator stator core vent duct spacer posts

DOEpatents

Griffith, John Wesley; Tong, Wei

2003-06-24

Generator stator cores are constructed by stacking many layers of magnetic laminations. Ventilation ducts may be inserted between these layers by inserting spacers into the core stack. The ventilation ducts allow for the passage of cooling gas through the core during operation. The spacers or spacer posts are positioned between groups of the magnetic laminations to define the ventilation ducts. The spacer posts are secured with longitudinal axes thereof substantially parallel to the core axis. With this structure, core tightness can be assured while maximizing ventilation duct cross section for gas flow and minimizing magnetic loss in the spacers.

Measurement of Fine Particles From Mobile and Stationary Sources, and Reducing the Air Conditioner Power Consumption in Hybrid Electric Vehicles

NASA Astrophysics Data System (ADS)

Brewer, Eli Henry

We study the PM2.5and ultrafine exhaust emissions from a new natural gas-fired turbine power facility to better understand air pollution in California. To characterize the emissions from new natural gas turbines, a series of tests were performed on a GE LMS100 gas turbine. These tests included PM2.5 and wet chemical tests for SO2/SO 3 and NH3, as well as ultrafine (less than 100 nm in diameter) particulate matter measurements. The turbine exhaust had an average particle number concentration that was 2.3x103 times higher than ambient air. The majority of these particles were nanoparticles; at the 100 nm size, stack particle concentrations were about 20 times higher than ambient, and increased to 3.9x104 times higher on average in the 2.5 - 3 nm particle size range. This study also found that ammonia emissions were higher than expected, but in compliance with permit conditions. This was possibly due to an ammonia imbalance entering the catalyst, some flue gas bypassing the catalyst, or not enough catalyst volume. SO3 accounted for an average of 23% of the total sulfur oxides emissions measured. Some of the SO3 is formed in the combustion process, it is likely that the majority formed as the SO2 in the combustion products passed across the oxidizing CO catalyst and SCR catalyst. The 100 MW turbine sampled in this study emitted particle loadings similar to those previously measured from turbines in the SCAQMD area, however, the turbine exhaust contained far more particles than ambient air. The power consumed by an air conditioner accounts for a significant fraction of the total power used by hybrid and electric vehicles especially during summer. This study examined the effect of recirculation of cabin air on power consumption of mobile air conditioners both in-lab and on-road. Real time power consumption and vehicle mileage were recorded by an On Board Diagnostic monitor and carbon balance method. Vehicle mileage improved with increased cabin air recirculation. The recirculation of cabin air also significantly reduced in-cabin particle concentrations. Recirculation of cabin air is an excellent and immediate solution to increase vehicle mileage and improve cabin air quality.

40 CFR 63.7293 - What work practice standards must I meet for fugitive pushing emissions if I have a non-recovery...

Code of Federal Regulations, 2010 CFR

2010-07-01

... meet for fugitive pushing emissions if I have a non-recovery coke oven battery? 63.7293 Section 63.7293... Standards for Hazardous Air Pollutants for Coke Ovens: Pushing, Quenching, and Battery Stacks Emission... pushing emissions if I have a non-recovery coke oven battery? (a) You must meet the requirements in...

40 CFR 63.7293 - What work practice standards must I meet for fugitive pushing emissions if I have a non-recovery...

Code of Federal Regulations, 2013 CFR

2013-07-01

... meet for fugitive pushing emissions if I have a non-recovery coke oven battery? 63.7293 Section 63.7293... Standards for Hazardous Air Pollutants for Coke Ovens: Pushing, Quenching, and Battery Stacks Emission... pushing emissions if I have a non-recovery coke oven battery? (a) You must meet the requirements in...

40 CFR 63.7293 - What work practice standards must I meet for fugitive pushing emissions if I have a non-recovery...

Code of Federal Regulations, 2012 CFR

2012-07-01

... meet for fugitive pushing emissions if I have a non-recovery coke oven battery? 63.7293 Section 63.7293... Standards for Hazardous Air Pollutants for Coke Ovens: Pushing, Quenching, and Battery Stacks Emission... pushing emissions if I have a non-recovery coke oven battery? (a) You must meet the requirements in...

40 CFR 63.7293 - What work practice standards must I meet for fugitive pushing emissions if I have a non-recovery...

Code of Federal Regulations, 2014 CFR

2014-07-01

... meet for fugitive pushing emissions if I have a non-recovery coke oven battery? 63.7293 Section 63.7293... Standards for Hazardous Air Pollutants for Coke Ovens: Pushing, Quenching, and Battery Stacks Emission... pushing emissions if I have a non-recovery coke oven battery? (a) You must meet the requirements in...

40 CFR 63.7293 - What work practice standards must I meet for fugitive pushing emissions if I have a non-recovery...

Code of Federal Regulations, 2011 CFR

2011-07-01

... meet for fugitive pushing emissions if I have a non-recovery coke oven battery? 63.7293 Section 63.7293... Standards for Hazardous Air Pollutants for Coke Ovens: Pushing, Quenching, and Battery Stacks Emission... pushing emissions if I have a non-recovery coke oven battery? (a) You must meet the requirements in...

MONITORING OF INCINERATOR EMISSIONS

EPA Science Inventory

Monitoring of Incinerator Emissions is a chapter to be included in a book entitled Hazardous Waste Incineration, edited by A. Sarofim and D. Pershing, and published by John Wiley and Sons. he chapter describes stack sampling and analysis procedures in use on hazardous waste incin...

White-emissive tandem-type hybrid organic/polymer diodes with (0.33, 0.33) chromaticity coordinates.

PubMed

Guo, Tzung-Fang; Wen, Ten-Chin; Huang, Yi-Shun; Lin, Ming-Wei; Tsou, Chuan-Cheng; Chung, Chia-Tin

2009-11-09

This study reports fabrication of white-emissive, tandem-type, hybrid organic/polymer light-emitting diodes (O/PLED). The tandem devices are made by stacking a blue-emissive OLED on a yellow-emissive phenyl-substituted poly(para-phenylene vinylene) copolymer-based PLED and applying an organic oxide/Al/molybdenum oxide (MoO(3)) complex structure as a connecting structure or charge-generation layer (CGL). The organic oxide/Al/MoO(3) CGL functions as an effective junction interface for the transport and injection of opposite charge carriers through the stacked configuration. The electroluminescence (EL) spectra of the tandem-type devices can be tuned by varying the intensity of the emission in each emissive component to yield the visible-range spectra from 400 to 750 nm, with Commission Internationale de l'Eclairage chromaticity coordinates of (0.33, 0.33) and a high color rendering capacity as used for illumination. The EL spectra also exhibit good color stability under various bias conditions. The tandem-type device of emission with chromaticity coordinates, (0.30, 0.31), has maximum brightness and luminous efficiency over 25,000 cd/m(2) and approximately 4.2 cd/A, respectively.

The Impact of Ship-Produced Aerosols on the Microstructure and Albedo of Warm Marine Stratocumulus Clouds: A Test of MAST Hypotheses 1i and 1ii.

NASA Astrophysics Data System (ADS)

Durkee, P. A.; Noone, K. J.; Ferek, R. J.; Johnson, D. W.; Taylor, J. P.; Garrett, T. J.; Hobbs, P. V.; Hudson, J. G.; Bretherton, C. S.; Innis, G.; Frick, G. M.; Hoppel, W. A.; O'Dowd, C. D.; Russell, L. M.; Gasparovic, R.; Nielsen, K. E.; Tessmer, S. A.; Öström, E.;  Osborne, S. R.;  Flagan, R. C.;  Seinfeld, J. H.;  Rand, H.

2000-08-01

Anomalously high reflectivity tracks in stratus and stratocumulus sheets associated with ships (known as ship tracks) are commonly seen in visible and near-infrared satellite imagery. Until now there have been only a limited number of in situ measurements made in ship tracks. The Monterey Area Ship Track (MAST) experiment, which was conducted off the coast of California in June 1994, provided a substantial dataset on ship emissions and their effects on boundary layer clouds. Several platforms, including the University of Washington C-131A aircraft, the Meteorological Research Flight C-130 aircraft, the National Aeronautics and Space Administration ER-2 aircraft, the Naval Research Laboratory airship, the Research Vessel Glorita, and dedicated U.S. Navy ships, participated in MAST in order to study processes governing the formation and maintenance of ship tracks.This paper tests the hypotheses that the cloud microphysical changes that produce ship tracks are due to (a) particulate emission from the ship's stack and/or (b) sea-salt particles from the ship's wake. It was found that ships powered by diesel propulsion units that emitted high concentrations of aerosols in the accumulation mode produced ship tracks. Ships that produced few particles (such as nuclear ships), or ships that produced high concentrations of particles but at sizes too small to be activated as cloud drops in typical stratocumulus (such as gas turbine and some steam-powered ships), did not produce ship tracks. Statistics and case studies, combined with model simulations, show that provided a cloud layer is susceptible to an aerosol perturbation, and the atmospheric stability enables aerosol to be mixed throughout the boundary layer, the direct emissions of cloud condensation nuclei from the stack of a diesel-powered ship is the most likely, if not the only, cause of the formation of ship tracks. There was no evidence that salt particles from ship wakes cause ship tracks.

Anode protection system for shutdown of solid oxide fuel cell system

DOEpatents

Li, Bob X; Grieves, Malcolm J; Kelly, Sean M

2014-12-30

An Anode Protection Systems for a SOFC system, having a Reductant Supply and safety subsystem, a SOFC anode protection subsystem, and a Post Combustion and slip stream control subsystem. The Reductant Supply and safety subsystem includes means for generating a reducing gas or vapor to prevent re-oxidation of the Ni in the anode layer during the course of shut down of the SOFC stack. The underlying ammonia or hydrogen based material used to generate a reducing gas or vapor to prevent the re-oxidation of the Ni can be in either a solid or liquid stored inside a portable container. The SOFC anode protection subsystem provides an internal pressure of 0.2 to 10 kPa to prevent air from entering into the SOFC system. The Post Combustion and slip stream control subsystem provides a catalyst converter configured to treat any residual reducing gas in the slip stream gas exiting from SOFC stack.

Industrial chimney monitoring - contemporary methods

NASA Astrophysics Data System (ADS)

Kaszowska, Olga; Gruchlik, Piotr; Mika, Wiesław

2018-04-01

The paper presents knowledge acquired during the monitoring of a flue-gas stack, performed as part of technical and scientific surveillance of mining activity and its impact on industrial objects. The chimney is located in an area impacted by mining activity since the 1970s, from a coal mine which is no longer in existence. In the period of 2013-16, this area was subject to mining carried out by a mining entrepreneur who currently holds a license to excavate hard coal. Periodic measurements of the deflection of the 113-meter chimney are performed using conventional geodetic methods. The GIG used 3 methods to observe the stack: landbased 3D laser scanning, continuous deflection monitoring with a laser sensor, and drone-based visual inspections. The drone offered the possibility to closely inspect the upper sections of the flue-gas stack, which are difficult to see from the ground level.

Energy-Sensitive Ion- and Cathode-Luminescent Radiation-Beam Monitors Based on Multilayer Thin-Film Designs.

PubMed

Gil-Rostra, Jorge; Ferrer, Francisco J; Espinós, Juan Pedro; González-Elipe, Agustín R; Yubero, Francisco

2017-05-17

A multilayer luminescent design concept is presented to develop energy-sensitive radiation-beam monitors on the basis of colorimetric analysis. Each luminescent layer within the stack consists of rare-earth-doped transparent oxides of optical quality and a characteristic luminescent emission under excitation with electron or ion beams. For a given type of particle beam (electron, protons, α particles, etc.), its penetration depth and therefore its energy loss at a particular buried layer within the multilayer stack depend on the energy of the initial beam. The intensity of the luminescent response of each layer is proportional to the energy deposited by the radiation beam within the layer, so characteristic color emission will be achieved if different phosphors are considered in the layers of the luminescent stack. Phosphor doping, emission efficiency, layer thickness, and multilayer structure design are key parameters relevant to achieving a broad colorimetric response. Two case examples are designed and fabricated to illustrate the capabilities of these new types of detector to evaluate the kinetic energy of either electron beams of a few kilo-electron volts or α particles of a few mega-electron volts.

Stacking of ZnSe/ZnCdSe Multi-Quantum Wells on GaAs (100) by Epitaxial Lift-Off

NASA Astrophysics Data System (ADS)

Eldose, N. M.; Zhu, J.; Mavridi, N.; Prior, Kevin; Moug, R. T.

2018-05-01

Here we present stacking of GaAs/ZnSe/ZnCdSe single-quantum well (QW) structures using epitaxial lift-off (ELO). Molecular beam epitaxy (MBE)-grown II-VI QW structure was lifted using our standard ELO technique. The QW structures were transferred onto glass plates and then subsequent layers stacked on top of each other to form a triple-QW structure. This was compared to an MBE-grown multiple-QW (MQW) structure of similar design. Low-temperature (77 K) photoluminescence (PL) spectroscopy was used to compare the two structures and showed no obvious degradation of the ELO stacked layer. It was observed that by stacking the single QW layer on itself we could increase the PL emission intensity beyond that of the grown MQW structure while maintaining narrow line width.

75 FR 65067 - National Emission Standards for Hazardous Air Pollutant Emissions: Hard and Decorative Chromium...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-10-21

... non-air quality health and environmental impacts) and are commonly referred to as maximum achievable... process, stack, storage, or fugitive emissions point, (D) are design, equipment, work practice, or... combination of the above. CAA section 112(d)(2)(A)-(E). The MACT standard may take the form of a design...

Battery condenser system PM10 emission factors and rates for cotton gins: Method 201A PM10 sizing cyclones

USDA-ARS?s Scientific Manuscript database

This manuscript is part of a series of manuscripts that to characterize cotton gin emissions from the standpoint of stack sampling. The impetus behind this project was the urgent need to collect additional cotton gin emissions data to address current regulatory issues. A key component of this study ...

Application of particle size distributions to total particulate stack samples to estimate PM2.5 and PM10 emission factors for agricultural sources

USDA-ARS?s Scientific Manuscript database

Particle size distributions (PSD) have long been used to more accurately estimate the PM10 fraction of total particulate matter (PM) stack samples taken from agricultural sources. These PSD analyses were typically conducted using a Coulter Counter with 50 micrometer aperture tube. With recent increa...

Behavior of Mercury Emissions from a Commercial Coal-Fired Utility Boiler: TheRelationship Between Stack Speciation and Near-Field Plume Measurements

EPA Science Inventory

The reduction of divalent gaseous mercury (Hg^II) to elemental gaseous mercury (Hg⁰) in a commercial coal-fired power plant (CFPP)exhaust plume was investigated by simultaneous measurement in-stack and in-plume as part of a collaborative study among the U.S....

Distribution and Fate of Mercury in Pulverized Bituminous Coal-Fired Power Plants in Coal Energy-Dominant Huainan City, China.

PubMed

Chen, Bingyu; Liu, Guijian; Sun, Ruoyu

2016-05-01

A better understanding on the partitioning behavior of mercury (Hg) during coal combustion in large-scale coal-fired power plants is fundamental for drafting Hg-emission control regulations. Two large coal-fired utility boilers, equipped with electrostatic precipitators (ESPs) and a wet flue gas desulfurization (WFGD) system, respectively, in coal energy-dominant Huainan City, China, were selected to investigate the distribution and fate of Hg during coal combustion. In three sampling campaigns, we found that Hg in bottom ash was severely depleted with a relative enrichment (RE) index <7 %, whereas the RE index for fly ash (9-54%) was comparatively higher and variable. Extremely high Hg was concentrated in gypsum (≤4500 ng/g), which is produced in the WFGD system. Mass balance calculation shows that the shares of Hg in bottom ash, fly ash, WFGD products (gypsum, effluents, sludge), and stack emissions were <2, 17-32, 7-22, and 54-82%, respectively. The Hg-removal efficiencies of ESPs, WFGD, and ESPs + WFGD were 17-32, 10-29, and 36-46%, respectively. The Hg-emission factor of studied boilers was in a high range of 0.24-0.29 g Hg/t coal. We estimated that Hg emissions in all Huainan coal-fired power plants varied from 1.8 Mg in 2003 to 7.3 Mg in 2010.

Characterization of a novel, highly integrated tubular solid oxide fuel cell system using high-fidelity simulation tools

NASA Astrophysics Data System (ADS)

Kattke, K. J.; Braun, R. J.

2011-08-01

A novel, highly integrated tubular SOFC system intended for small-scale power is characterized through a series of sensitivity analyses and parametric studies using a previously developed high-fidelity simulation tool. The high-fidelity tubular SOFC system modeling tool is utilized to simulate system-wide performance and capture the thermofluidic coupling between system components. Stack performance prediction is based on 66 anode-supported tubular cells individually evaluated with a 1-D electrochemical cell model coupled to a 3-D computational fluid dynamics model of the cell surroundings. Radiation is the dominate stack cooling mechanism accounting for 66-92% of total heat loss at the outer surface of all cells at baseline conditions. An average temperature difference of nearly 125 °C provides a large driving force for radiation heat transfer from the stack to the cylindrical enclosure surrounding the tube bundle. Consequently, cell power and voltage disparities within the stack are largely a function of the radiation view factor from an individual tube to the surrounding stack can wall. The cells which are connected in electrical series, vary in power from 7.6 to 10.8 W (with a standard deviation, σ = 1.2 W) and cell voltage varies from 0.52 to 0.73 V (with σ = 81 mV) at the simulation baseline conditions. It is observed that high cell voltage and power outputs directly correspond to tubular cells with the smallest radiation view factor to the enclosure wall, and vice versa for tubes exhibiting low performance. Results also reveal effective control variables and operating strategies along with an improved understanding of the effect that design modifications have on system performance. By decreasing the air flowrate into the system by 10%, the stack can wall temperature increases by about 6% which increases the minimum cell voltage to 0.62 V and reduces deviations in cell power and voltage by 31%. A low baseline fuel utilization is increased by decreasing the fuel flowrate and by increasing the stack current demand. Simulation results reveal fuel flow as a poor control variable because excessive tail-gas combustor temperatures limit fuel flow to below 110% of the baseline flowrate. Additionally, system efficiency becomes inversely proportional to fuel utilization over the practical fuel flow range. Stack current is found to be an effective control variable in this type of system because system efficiency becomes directly proportional to fuel utilization. Further, the integrated system acts to dampen temperature spikes when fuel utilization is altered by varying current demand. Radiation remains the dominate heat transfer mechanism within the stack even if stack surfaces are polished lowering emissivities to 0.2. Furthermore, the sensitivity studies point to an optimal system insulation thickness that balances the overall system volume and total conductive heat loss.

REDUCTION OF COAL-BASED METAL EMISSIONS BY FURNACE SORBENT INJECTION

EPA Science Inventory

The ability of sorbent injection technology to reduce the potential for trace metal emissions from coal combustion was researched. Pilot scale tests of high-temperature furnace sorbent injection were accompanied by stack sampling for coal-based, metallic air toxics. Tested sorben...

MOLECULAR GAS VELOCITY DISPERSIONS IN THE ANDROMEDA GALAXY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Caldú-Primo, Anahi; Schruba, Andreas, E-mail: caldu@mpia.de, E-mail: schruba@mpe.mpg.de

In order to characterize the distribution of molecular gas in spiral galaxies, we study the line profiles of CO (1 – 0) emission in Andromeda, our nearest massive spiral galaxy. We compare observations performed with the IRAM 30 m single-dish telescope and with the CARMA interferometer at a common resolution of 23 arcsec ≈ 85 pc × 350 pc and 2.5 km s{sup −1}. When fitting a single Gaussian component to individual spectra, the line profile of the single dish data is a factor of 1.5 ± 0.4 larger than the interferometric data one. This ratio in line widths ismore » surprisingly similar to the ratios previously observed in two other nearby spirals, NGC 4736 and NGC 5055, but measured at ∼0.5–1 kpc spatial scale. In order to study the origin of the different line widths, we stack the individual spectra in five bins of increasing peak intensity and fit two Gaussian components to the stacked spectra. We find a unique narrow component of FWHM = 7.5 ± 0.4 km s{sup −1} visible in both the single dish and the interferometric data. In addition, a broad component with FWHM = 14.4 ± 1.5 km s{sup −1} is present in the single-dish data, but cannot be identified in the interferometric data. We interpret this additional broad line width component detected by the single dish as a low brightness molecular gas component that is extended on spatial scales >0.5 kpc, and thus filtered out by the interferometer. We search for evidence of line broadening by stellar feedback across a range of star formation rates but find no such evidence on ∼100 pc spatial scale when characterizing the line profile by a single Gaussian component.« less

A dilute Cu(Ni) alloy for synthesis of large-area Bernal stacked bilayer graphene using atmospheric pressure chemical vapour deposition

DOE Office of Scientific and Technical Information (OSTI.GOV)

Madito, M. J.; Bello, A.; Dangbegnon, J. K.

2016-01-07

A bilayer graphene film obtained on copper (Cu) foil is known to have a significant fraction of non-Bernal (AB) stacking and on copper/nickel (Cu/Ni) thin films is known to grow over a large-area with AB stacking. In this study, annealed Cu foils for graphene growth were doped with small concentrations of Ni to obtain dilute Cu(Ni) alloys in which the hydrocarbon decomposition rate of Cu will be enhanced by Ni during synthesis of large-area AB-stacked bilayer graphene using atmospheric pressure chemical vapour deposition. The Ni doped concentration and the Ni homogeneous distribution in Cu foil were confirmed with inductively coupledmore » plasma optical emission spectrometry and proton-induced X-ray emission. An electron backscatter diffraction map showed that Cu foils have a single (001) surface orientation which leads to a uniform growth rate on Cu surface in early stages of graphene growth and also leads to a uniform Ni surface concentration distribution through segregation kinetics. The increase in Ni surface concentration in foils was investigated with time-of-flight secondary ion mass spectrometry. The quality of graphene, the number of graphene layers, and the layers stacking order in synthesized bilayer graphene films were confirmed by Raman and electron diffraction measurements. A four point probe station was used to measure the sheet resistance of graphene films. As compared to Cu foil, the prepared dilute Cu(Ni) alloy demonstrated the good capability of growing large-area AB-stacked bilayer graphene film by increasing Ni content in Cu surface layer.« less

A dilute Cu(Ni) alloy for synthesis of large-area Bernal stacked bilayer graphene using atmospheric pressure chemical vapour deposition

NASA Astrophysics Data System (ADS)

Madito, M. J.; Bello, A.; Dangbegnon, J. K.; Oliphant, C. J.; Jordaan, W. A.; Momodu, D. Y.; Masikhwa, T. M.; Barzegar, F.; Fabiane, M.; Manyala, N.

2016-01-01

A bilayer graphene film obtained on copper (Cu) foil is known to have a significant fraction of non-Bernal (AB) stacking and on copper/nickel (Cu/Ni) thin films is known to grow over a large-area with AB stacking. In this study, annealed Cu foils for graphene growth were doped with small concentrations of Ni to obtain dilute Cu(Ni) alloys in which the hydrocarbon decomposition rate of Cu will be enhanced by Ni during synthesis of large-area AB-stacked bilayer graphene using atmospheric pressure chemical vapour deposition. The Ni doped concentration and the Ni homogeneous distribution in Cu foil were confirmed with inductively coupled plasma optical emission spectrometry and proton-induced X-ray emission. An electron backscatter diffraction map showed that Cu foils have a single (001) surface orientation which leads to a uniform growth rate on Cu surface in early stages of graphene growth and also leads to a uniform Ni surface concentration distribution through segregation kinetics. The increase in Ni surface concentration in foils was investigated with time-of-flight secondary ion mass spectrometry. The quality of graphene, the number of graphene layers, and the layers stacking order in synthesized bilayer graphene films were confirmed by Raman and electron diffraction measurements. A four point probe station was used to measure the sheet resistance of graphene films. As compared to Cu foil, the prepared dilute Cu(Ni) alloy demonstrated the good capability of growing large-area AB-stacked bilayer graphene film by increasing Ni content in Cu surface layer.

40 CFR Table 2 to Subpart Cccc of... - Requirements for Performance Tests

Code of Federal Regulations, 2010 CFR

2010-07-01

... port's location and the number of traverse points Method 1* 3. Measure volumetric flow rate. Method 2* 4. Perform gas analysis to determine the dry molecular weight of the stack gas Method 3* 5...

Size distribution and concentrations of heavy metals in atmospheric aerosols originating from industrial emissions as predicted by the HYSPLIT model

NASA Astrophysics Data System (ADS)

Chen, Bing; Stein, Ariel F.; Maldonado, Pabla Guerrero; Sanchez de la Campa, Ana M.; Gonzalez-Castanedo, Yolanda; Castell, Nuria; de la Rosa, Jesus D.

2013-06-01

This study presents a description of the emission, transport, dispersion, and deposition of heavy metals contained in atmospheric aerosols emitted from a large industrial complex in southern Spain using the HYSPLIT model coupled with high- (MM5) and low-resolution (GDAS) meteorological simulations. The dispersion model was configured to simulate eight size fractions (<0.33, 0.66, 1.3, 2.5, 5, 14, 17, and >17 μm) of metals based on direct measurements taken at the industrial emission stacks. Twelve stacks in four plants were studied and the stacks showed considerable differences for both emission fluxes and size ranges of metals. We model the dispersion of six major metals; Cr, Co, Ni, La, Zn, and Mo, which represent 77% of the total mass of the 43 measured elements. The prediction shows that the modeled industrial emissions produce an enrichment of heavy metals by a factor of 2-5 for local receptor sites when compared to urban and rural background areas in Spain. The HYSPLIT predictions based on the meteorological fields from MM5 show reasonable consistence with the temporal evolution of concentrations of Cr, Co, and Ni observed at three sites downwind of the industrial area. The magnitude of concentrations of metals at two receptors was underestimated for both MM5 (by a factor of 2-3) and GDAS (by a factor of 4-5) meteorological runs. The model prediction shows that heavy metal pollution from industrial emissions in this area is dominated by the ultra-fine (<0.66 μm) and fine (<2.5 μm) size fractions.

Polycyclic aromatic hydrocarbon emission profiles and removal efficiency by electrostatic precipitator and wetfine scrubber in an iron ore sintering plant

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ettore Guerriero; Antonina Lutri; Rosanna Mabilia

2008-11-15

A monitoring campaign of polychlorinated dibenzo-p-dioxins and dibenzofurans, polyaromatic hydrocarbons (PAHs), and polychlorinated biphenyl was carried out in an Italian iron ore sintering plant by sampling the combustion gases at the electrostatic precipitator (ESP) outlet, at the Wetfine scrubber (WS) outlet, and by collecting the ESP dust. Few data are available on these micropollutants produced in iron ore sintering plants, particularly from Italian plants. This study investigates the PAH emission profiles and the removal efficiency of ESPs and WS. PAHs were determined at the stack, ESP outlet flue gases, and in ESP dust to characterize the emission profiles and themore » performance of the ESP and the WS for reducing PAH emission. The 11 PAHs monitored are listed in the Italian legislative decree 152/2006. The mean total PAH sum concentration in the stack flue gases is 3.96 {mu}g/N m{sup 3}, in ESP outlet flue gases is 9.73 {mu}g/N m{sup 3}, and in ESP dust is 0.53 {mu}g/g. Regarding the emission profiles, the most abundant compound is benzo(b)fluoranthene, which has a relative low BaP toxic equivalency factors (TEF) value, followed by dibenzo(a,l)pyrene, which has a very high BaP(TEF) value. The emission profiles in ESP dust and in the flue gases after the ESP show some changes, whereas the fingerprint in ESP and stack flue gases is very similar. The removal efficiency of the ESP and of WS on the total PAH concentration is 5.2 and 59.5%, respectively. 2 figs., 5 tabs.« less

Homogeneous spectral spanning of terahertz semiconductor lasers with radio frequency modulation.

PubMed

Wan, W J; Li, H; Zhou, T; Cao, J C

2017-03-08

Homogeneous broadband and electrically pumped semiconductor radiation sources emitting in the terahertz regime are highly desirable for various applications, including spectroscopy, chemical sensing, and gas identification. In the frequency range between 1 and 5 THz, unipolar quantum cascade lasers employing electron inter-subband transitions in multiple-quantum-well structures are the most powerful semiconductor light sources. However, these devices are normally characterized by either a narrow emission spectrum due to the narrow gain bandwidth of the inter-subband optical transitions or an inhomogeneous broad terahertz spectrum from lasers with heterogeneous stacks of active regions. Here, we report the demonstration of homogeneous spectral spanning of long-cavity terahertz semiconductor quantum cascade lasers based on a bound-to-continuum and resonant phonon design under radio frequency modulation. At a single drive current, the terahertz spectrum under radio frequency modulation continuously spans 330 GHz (~8% of the central frequency), which is the record for single plasmon waveguide terahertz lasers with a bound-to-continuum design. The homogeneous broadband terahertz sources can be used for spectroscopic applications, i.e., GaAs etalon transmission measurement and ammonia gas identification.

Homogeneous spectral spanning of terahertz semiconductor lasers with radio frequency modulation

PubMed Central

Wan, W. J.; Li, H.; Zhou, T.; Cao, J. C.

2017-01-01

Homogeneous broadband and electrically pumped semiconductor radiation sources emitting in the terahertz regime are highly desirable for various applications, including spectroscopy, chemical sensing, and gas identification. In the frequency range between 1 and 5 THz, unipolar quantum cascade lasers employing electron inter-subband transitions in multiple-quantum-well structures are the most powerful semiconductor light sources. However, these devices are normally characterized by either a narrow emission spectrum due to the narrow gain bandwidth of the inter-subband optical transitions or an inhomogeneous broad terahertz spectrum from lasers with heterogeneous stacks of active regions. Here, we report the demonstration of homogeneous spectral spanning of long-cavity terahertz semiconductor quantum cascade lasers based on a bound-to-continuum and resonant phonon design under radio frequency modulation. At a single drive current, the terahertz spectrum under radio frequency modulation continuously spans 330 GHz (~8% of the central frequency), which is the record for single plasmon waveguide terahertz lasers with a bound-to-continuum design. The homogeneous broadband terahertz sources can be used for spectroscopic applications, i.e., GaAs etalon transmission measurement and ammonia gas identification. PMID:28272492

COST EFFECTIVE CONTROL OF HEXAVALENT CHROMIUM AIR EMISSIONS FROM FUNCTIONAL CHROMIUM ELECTROPLATING

EPA Science Inventory

This paper will summrize thie pollution prevention (p2) method to control stack emissions from hard chromium plating operations performed by the USEPA's National Risk Management Research Laboratory (NRMRL) over the last four years. During literature research and user surveys, it...

Unitized Regenerative Fuel Cell System Gas Storage/Radiator Development

NASA Technical Reports Server (NTRS)

Jakupca, Ian; Burke, Kenneth A.

2003-01-01

The ancillary components for Unitized Regenerative Fuel Cell (URFC) Energy Storage System are being developed at the NASA Glenn Research Center. This URFC system is unique in that it uses the surface area of the hydrogen and oxygen storage tanks as radiating heat surfaces for overall thermal control of the system. The waste heat generated by the URFC stack during charging and discharging is transferred from the cell stack to the surface of each tank by loop heat pipes. The heat pipes are coiled around each tank and covered with a thin layer of thermally conductive layer of carbon composite. The thin layer of carbon composite acts as a fin structure that spreads the heat away from the heat pipe and across the entire tank surface. Two different sized commercial grade composite tanks were constructed with integral heat pipes and tested in a thermal vacuum chamber to examine the feasibility of using the storage tanks as system radiators. The storage radiators were subjected to different steady-state heat loads and varying heat load profiles. The surface emissivity and specific heat capacity of each tank were calculated. The results were incorporated into a model that simulates the performance of similar radiators using lightweight, space rated carbon composite tanks.

40 CFR 60.715 - Test methods and procedures.

Code of Federal Regulations, 2010 CFR

2010-07-01

... base film (i.e., the sample shall include any dilution solvent or other VOC added during the... for gas analysis. (f) Method 4 is used for stack gas moisture. (g) Methods 2, 2A, 2C, 2D, 3, and 4...

Energy recovery and emissions of PBDD/Fs and PBDEs from cocombustion of woodchip and wastewater sludge in an industrial boiler.

PubMed

Chang, Shun-Shiang Chang; Lee, Wen-Jhy Lee; Wang, Lin-Chi Wang; Chang-Chien, Guo-Ping Chang-Chien; Wu, Chang-Yu

2013-01-01

The emissions of polybrominated dibenzo-pdioxins,dibenzofurans (PBDD/Fs), and polybrominated diphenyl ethers (PBDEs) from trial combustion of 10 wt % dried industrial wastewater-treatment sludge (IWTS) and 90 wt % woodchip in an industrial boiler were investigated and compared to that from woodchip combustion. The PBDD/F toxic equivalent (TEQ) andPBDE emissions increased from 0.121 pg TEQ Nm−3 and 2260 pgNm−3, respectively, of the woodchip combustion to 0.211 pg TEQNm−3 and 4200 pg Nm−3, respectively, of the trial combustion.PBDD/F and PBDE congener profiles of inputs and outputs of the same type of combustion were similar; they also show similarity between woodchip and trial combustions, revealing that the destruction pathway was little affected by the introduction of the IWTS. The fates of PBDD/Fs and PBDEs show that the indigenous pollutants in the feed were effectively depleted (>93.5%). The dominant releasing route of PBDD/F and PBDE shifted from the stack flue gas of woodchip combustion to the ashes of trial combustion. This study demonstrates that co-combustion not only handles the fast growing sludge stream but also yields a saving of 26.3% in the fuel cost and treatment fees of sludge and ashes.

Boiler Stack Gas Heat Recovery

DTIC Science & Technology

1987-09-01

flue gas environ- ment. Conventional finned metal (aluminum, copper, stainless steel) tubes should not be used unless controls maintain the outer metal...xý Table 5. Summary of Actual Applications of Fiberglass Reinforced Plastic (FRP) in Corrosive Flue Gas Desulfurization Service Equipment Corrosive...process-steam/water heating. The procedure for estimating the energy potential of a given flue - gas stream is explained in detail with sample plots

Should particle size analysis data be combined with EPA approved sampling method data in the development of AP-42 emission factors?

USDA-ARS?s Scientific Manuscript database

A cotton ginning industry-supported project was initiated in 2008 and completed in 2013 to collect additional data for U.S. Environmental Protection Agency’s (EPA) Compilation of Air Pollution Emission Factors (AP-42) for PM10 and PM2.5. Stack emissions were collected using particle size distributio...

Impacts of Energy Sector Emissions on PM2.5 Air Quality in Northern India

NASA Astrophysics Data System (ADS)

Karambelas, A. N.; Kiesewetter, G.; Heyes, C.; Holloway, T.

2015-12-01

India experiences high concentrations of fine particulate matter (PM2.5), and several Indian cities currently rank among the world's most polluted cities. With ongoing urbanization and a growing economy, emissions from different energy sectors remain major contributors to air pollution in India. Emission sectors impact ambient air quality differently due to spatial distribution (typical urban vs. typical rural sources) as well as source height characteristics (low-level vs. high stack sources). This study aims to assess the impacts of emissions from three distinct energy sectors—transportation, domestic, and electricity—on ambient PM2.5­­ in northern India using an advanced air quality analysis framework based on the U.S. EPA Community Multi-Scale Air Quality (CMAQ) model. Present air quality conditions are simulated using 2010 emissions from the Greenhouse Gas-Air Pollution Interaction and Synergies (GAINS) model. Modeled PM2.5 concentrations are compared with satellite observations of aerosol optical depth (AOD) from the Moderate Imaging Spectroradiometer (MODIS) for 2010. Energy sector emissions impacts on future (2030) PM2.5 are evaluated with three sensitivity simulations, assuming maximum feasible reduction technologies for either transportation, domestic, or electricity sectors. These simulations are compared with a business as usual 2030 simulation to assess relative sectoral impacts spatially and temporally. CMAQ is modeled at 12km by 12km and include biogenic emissions from the Community Land Model coupled with the Model of Emissions of Gases and Aerosols in Nature (CLM-MEGAN), biomass burning emissions from the Global Fires Emissions Database (GFED), and ERA-Interim meteorology generated with the Weather Research and Forecasting (WRF) model for 2010 to quantify the impact of modified anthropogenic emissions on ambient PM2.5 concentrations. Energy sector emissions analysis supports decision-making to improve future air quality and public health in India.

PEM fuel cell monitoring system

DOEpatents

Meltser, Mark Alexander; Grot, Stephen Andreas

1998-01-01

Method and apparatus for monitoring the performance of H.sub.2 --O.sub.2 PEM fuel cells. Outputs from a cell/stack voltage monitor and a cathode exhaust gas H.sub.2 sensor are corrected for stack operating conditions, and then compared to predetermined levels of acceptability. If certain unacceptable conditions coexist, an operator is alerted and/or corrective measures are automatically undertaken.

Microenvironmental air quality impact of a commercial-scale biomass heating system.

PubMed

Tong, Zheming; Yang, Bo; Hopke, Philip K; Zhang, K Max

2017-01-01

Initiatives to displace petroleum and climate change mitigation have driven a recent increase in space heating with biomass combustion. However, there is ample evidence that biomass combustion emits significant quantities of health damaging pollutants. We investigated the near-source micro-environmental air quality impact of a biomass-fueled combined heat and power system equipped with an electrostatic precipitator (ESP) in Syracuse, NY. Two rooftop sampling stations with PM 2.5 and CO 2 analyzers were established in such that one could capture the plume while the other one served as the background for comparison depending on the wind direction. Four sonic anemometers were deployed around the stack to quantify spatially and temporally resolved local wind patterns. Fuel-based emission factors were derived based on near-source measurement. The Comprehensive Turbulent Aerosol Dynamics and Gas Chemistry (CTAG) model was then applied to simulate the spatial variations of primary PM 2.5 without ESP. Our analysis shows that the absence of ESP could lead to an almost 7 times increase in near-source primary PM 2.5 concentrations with a maximum concentration above 100 μg m -3 at the building rooftop. The above-ground "hotspots" would pose potential health risks to building occupants since particles could penetrate indoors via infiltration, natural ventilation, and fresh air intakes on the rooftop of multiple buildings. Our results demonstrated the importance of emission control for biomass combustion systems in urban area, and the need to take above-ground pollutant "hotspots" into account when permitting distributed generation. The effects of ambient wind speed and stack temperature, the suitability of airport meteorological data on micro-environmental air quality were explored, and the implications on mitigating near-source air pollution were discussed. Copyright © 2016 Elsevier Ltd. All rights reserved.

Installation of a stoker-coal preparation plant in Krakow, Poland. Technical progress report 11, October--December 1996

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

This project is one of eight projects selected under the assessment program in the Support of Eastern Democracy (SEED) Act of 0989 by the federal government to reduce low-level emission sources in the Krakow area of Poland. The objective of this Cooperative Agreement is to demonstrate that the quality of stack gas emissions can be improved through the substitution of run-of-mine coal by washed coal. To this end, EFH Coal Company will design, build, and operate a 300-mtph (330 stph) preparation plant and produce a low ash, double-screened washed coal for burning in a traveling-grate stoker in one of themore » many water heating plants in the city of Krakow. By burning this prepared coal under proper combustion condition, combustion efficiency will be increased, stoker maintenance will be lowered and the amount of carbon monoxide, sulfur dioxide and particulates in the stack gases will be reduced significantly. Contracts to: provide the raw-coal feed to the plant; dispose of plant wastes; burn the clean coal in a demonstration water heating plant in Krakow; and to market any surplus production are in place. An international irrevocable purchase order has been let for the procurement of a customized modular 300 mtph (330 stph) dense medium cyclone preparation plant to wash the 20 mm ({approx} 3/4 in.) by 5 mm. ({approx} 1/4 in.) size fraction of raw coal produced by the Katowice Coal Holding Company. This plant will be fabricated and shipped from the United States to Poland as soon as the final land-us and construction permits are granted.« less

Simplified and low cost optical remote sensing technology for fenceline monitoring of fugitive releases

EPA Science Inventory

Reducing fugitive emissions of hazardous air pollutants from industrial facilities is an ongoing priority for the U.S. Environmental Protection Agency (EPA). Unlike stack emissions, fugitive releases are difficult to detect due to their spatial extent and inherent temporal variab...

The Star Formation Rate Efficiency of Neutral Atomic-Dominated Hydrogen Gas in the Ooutskirts of Star-Forming Galaxies From z approx. 1 to z approx. 3

NASA Technical Reports Server (NTRS)

Rafelski, Marc; Gardner, Jonathan P.; Fumagalli, Michele; Neeleman, Marcel; Teplitz, Harry I.; Grogin, Norman; Koekemoer, Anton M.; Scarlata, Claudia

2016-01-01

Current observational evidence suggests that the star formation rate (SFR)efficiency of neutral atomic hydrogen gas measured in damped Ly(alpha) systems (DLAs) at z approx. 3 is more than 10 times lower than predicted by the Kennicutt-Schmidt (KS)relation. To understand the origin of this deficit, and to investigate possible evolution with redshift and galaxy properties, we measure the SFR efficiency of atomic gas at z approx. 1, z approx. 2, and z approx. 3 around star-forming galaxies. We use new robust photometric redshifts in the Hubble Ultra Deep Field to create galaxy stacks in these three redshift bins, and measure the SFR efficiency by combining DLA absorber statistics with the observed rest-frame UV emission in the galaxies' outskirts. We find that the SFR efficiency of H I gas at z > 1 is approx. 1%-3% of that predicted by the KS relation. Contrary to simulations and models that predict a reduced SFR efficiency with decreasing metallicity and thus with increasing redshift, we find no significant evolution in the SFR efficiency with redshift. Our analysis instead suggests that the reduced SFR efficiency is driven by the low molecular content of this atomic-dominated phase, with metallicity playing a secondary effect in regulating the conversion between atomic and molecular gas. This interpretation is supported by the similarity between the observed SFR efficiency and that observed in local atomic-dominated gas, such as in the outskirts of local spiral galaxies and local dwarf galaxies.

Fuel cell-gas turbine hybrid system design part II: Dynamics and control

NASA Astrophysics Data System (ADS)

McLarty, Dustin; Brouwer, Jack; Samuelsen, Scott

2014-05-01

Fuel cell gas turbine hybrid systems have achieved ultra-high efficiency and ultra-low emissions at small scales, but have yet to demonstrate effective dynamic responsiveness or base-load cost savings. Fuel cell systems and hybrid prototypes have not utilized controls to address thermal cycling during load following operation, and have thus been relegated to the less valuable base-load and peak shaving power market. Additionally, pressurized hybrid topping cycles have exhibited increased stall/surge characteristics particularly during off-design operation. This paper evaluates additional control actuators with simple control methods capable of mitigating spatial temperature variation and stall/surge risk during load following operation of hybrid fuel cell systems. The novel use of detailed, spatially resolved, physical fuel cell and turbine models in an integrated system simulation enables the development and evaluation of these additional control methods. It is shown that the hybrid system can achieve greater dynamic response over a larger operating envelope than either individual sub-system; the fuel cell or gas turbine. Results indicate that a combined feed-forward, P-I and cascade control strategy is capable of handling moderate perturbations and achieving a 2:1 (MCFC) or 4:1 (SOFC) turndown ratio while retaining >65% fuel-to-electricity efficiency, while maintaining an acceptable stack temperature profile and stall/surge margin.

40 CFR Table 1 to Subpart Bbbbb of... - Requirements for Performance Tests

Code of Federal Regulations, 2014 CFR

2014-07-01

... HAP used as the calibration gas must be the single organic HAP representing the largest percent of... determining compliance with a ppmv concentration limit. c. Conduct gas molecular weight analysis i. Method 3... York, NY 10016-5990) as an alternative to EPA Method 3B. d. Measure moisture content of the stack gas...

PRELIMINARY RESULTS OF THE AGC-4 IRRADIATION IN THE ADVANCED TEST REACTOR AND DESIGN OF AGC-5 (HTR16-18469)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Davenport, Michael; Petti, D. A.

The United States Department of Energy’s Advanced Reactor Technologies (ART) Program will irradiate up to six nuclear graphite creep experiments in the Advanced Test Reactor (ATR) located at the Idaho National Laboratory (INL). The graphite experiments are being irradiated over an approximate eight year period to support development of a graphite irradiation performance data base on the new nuclear grade graphites now available for use in high temperature gas reactors. The goals of the irradiation experiments are to obtain irradiation performance data, including irradiation creep, at different temperatures and loading conditions to support design of the Very High Temperature Gasmore » Reactor (VHTR), as well as other future gas reactors. The experiments each consist of a single capsule that contain six stacks of graphite specimens, with half of the graphite specimens in each stack under a compressive load, while the other half of the specimens are not be subjected to a compressive load during irradiation. The six stacks have differing compressive loads applied to the top half of diametrically opposite pairs of specimen stacks. A seventh specimen stack in the center of the capsule does not have a compressive load. The specimens are being irradiated in an inert sweep gas atmosphere with on-line temperature and compressive load monitoring and control. There are also samples taken of the sweep gas effluent to measure any oxidation or off-gassing of the specimens that may occur during initial start-up of the experiment. The first experiment, AGC-1, started its irradiation in September 2009, and the irradiation was completed in January 2011. The second experiment, AGC-2, started its irradiation in April 2011 and completed its irradiation in May 2012. The third experiment, AGC-3, started its irradiation in late November 2012 and completed in the April of 2014. AGC-4 is currently being irradiated in the ATR. This paper will briefly discuss the preliminary irradiation results of the AGC-4 experiment, as well as the design of AGC-5.« less

Exhaust-stack nozzle area and shape for individual cylinder exhaust-gas jet-propulsion system

NASA Technical Reports Server (NTRS)

Pinkel, Benjamin; Turner, Richard; Voss, Fred; Humble, Leroy V

1943-01-01

This report presents the results of an investigation conducted on the effect of exhaust-stack nozzle area, shape, and length on engine power, jet thrust, and gain in net thrust (engine propeller plus jet). Single-cylinder engine data were obtained using three straight stacks 25, 44, and 108 inches in length; an S-shaped stack, a 90 degree bend, a 180 degree bend, and a short straight stack having a closed branch faired into it. Each stack was fitted with nozzles varying in exit area from 0.91 square inch to the unrestricted area of the stack of 4.20 square inches. The engine was generally operated over a range of engine speeds from 1300 to 2100 r.p.m, inlet-manifold pressures from 22 to 30 inches of mercury absolute, and a fuel-air ratio of 0.08. The loss in engine power, the jet thrust, and the gain in net thrust are correlated in terms of several simple parameters. An example is given for determining the optimum nozzle area and the overall net thrust.

Laser Doppler systems in pollution monitoring

NASA Technical Reports Server (NTRS)

Miller, C. R.; Sonnenschein, C. M.; Herget, W. F.; Huffaker, R. M.

1976-01-01

The paper reports on a program undertaken to determine the feasibility of using a laser Doppler velocimeter (LDV) to measure smoke-stack gas exit velocity, particulate concentration, and mass flow. Measurements made with a CO2 laser Doppler radar system at a coal-burning power plant are compared with in-stack measurements made by a pitot tube. The operational principles of a LDV are briefly described along with the system employed in the present study. Data discussed include typical Doppler spectra from smoke-stack effluents at various laser elevation angles, the measured velocity profile across the stack exit, and the LDV-measured exit velocity as a function of the exit velocity measured by the in-stack instrument. The in-stack velocity is found to be about 14% higher than the LDV velocity, but this discrepancy is regarded as a systematic error. In general, linear relationships are observed between the laser data, the exit velocity, and the particulate concentration. It is concluded that an LDV has the capability of determining both the mass concentration and the mass flow from a power-plant smoke stack.

A supramolecular approach to fabricate highly emissive smart materials

PubMed Central

Liu, Kai; Yao, Yuxing; Kang, Yuetong; Liu, Yu; Han, Yuchun; Wang, Yilin; Li, Zhibo; Zhang, Xi

2013-01-01

The aromatic chromophores, for example, perylene diimides (PDIs) are well known for their desirable absorption and emission properties. However, their stacking nature hinders the exploitation of these properties and further applications. To fabricate emissive aggregates or solid-state materials, it has been common practice to decrease the degree of stacking of PDIs by incorporating substituents into the parent aromatic ring. However, such practice often involves difficultorganic synthesis with multiple steps. A supramolecular approach is established here to fabricate highly fluorescent and responsive soft materials, which has greatly decreases the number of required synthetic steps and also allows for a system with switchable photophysical properties. The highly fluorescent smart material exhibits great adaptivity and can be used as a supramolecular sensor for the rapid detection of spermine with high sensitivity and selectivity, which is crucial for the early diagnosis of malignant tumors. PMID:23917964

Design of wide-angle solar-selective absorbers using aperiodic metal-dielectric stacks.

PubMed

Sergeant, Nicholas P; Pincon, Olivier; Agrawal, Mukul; Peumans, Peter

2009-12-07

Spectral control of the emissivity of surfaces is essential in applications such as solar thermal and thermophotovoltaic energy conversion in order to achieve the highest conversion efficiencies possible. We investigated the spectral performance of planar aperiodic metal-dielectric multilayer coatings for these applications. The response of the coatings was optimized for a target operational temperature using needle-optimization based on a transfer matrix approach. Excellent spectral selectivity was achieved over a wide angular range. These aperiodic metal-dielectric stacks have the potential to significantly increase the efficiency of thermophotovoltaic and solar thermal conversion systems. Optimal coatings for concentrated solar thermal conversion were modeled to have a thermal emissivity <7% at 720K while absorbing >94% of the incident light. In addition, optimized coatings for solar thermophotovoltaic applications were modeled to have thermal emissivity <16% at 1750K while absorbing >85% of the concentrated solar radiation.

Development of a Hydrogasification Process for Co-Production of Substitute Natural Gas (SNG) and Electric Power from Western Coals-Phase I

DOE Office of Scientific and Technical Information (OSTI.GOV)

Raymond Hobbs

2007-05-31

The Advanced Hydrogasification Process (AHP)--conversion of coal to methane--is being developed through NETL with a DOE Grant and has successfully completed its first phase of development. The results so far are encouraging and have led to commitment by DOE/NETL to begin a second phase--bench scale reactor vessel testing, expanded engineering analysis and economic perspective review. During the next decade new means of generating electricity, and other forms of energy, will be introduced. The members of the AHP Team envision a need for expanded sources of natural gas or substitutes for natural gas, to fuel power generating plants. The initial workmore » the team has completed on a process to use hydrogen to convert coal to methane (pipeline ready gas) shows promising potential. The Team has intentionally slanted its efforts toward the needs of US electric utilities, particularly on fuels that can be used near urban centers where the greatest need for new electric generation is found. The process, as it has evolved, would produce methane from coal by adding hydrogen. The process appears to be efficient using western coals for conversion to a highly sought after fuel with significantly reduced CO{sub 2} emissions. Utilities have a natural interest in the preservation of their industry, which will require a dramatic reduction in stack emissions and an increase in sustainable technologies. Utilities tend to rank long-term stable supplies of fuel higher than most industries and are willing to trade some ratio of cost for stability. The need for sustainability, stability and environmentally compatible production are key drivers in the formation and progression of the AHP development. In Phase II, the team will add a focus on water conservation to determine how the basic gasification process can be best integrated with all the plant components to minimize water consumption during SNG production. The process allows for several CO{sub 2} reduction options including consumption of the CO{sub 2} in the original process as converted to methane. The process could under another option avoid emissions following the conversion to SNG through an adjunct algae conversion process. The algae would then be converted to fuels or other products. An additional application of the algae process at the end use natural gas fired plant could further reduce emissions. The APS team fully recognizes the competition facing the process from natural gas and imported liquid natural gas. While we expect those resources to set the price for methane in the near-term, the team's work to date indicates that the AHP process can be commercially competitive, with the added benefit of assuring long-term energy supplies from North American resources. Conversion of coal to a more readily transportable fuel that can be employed near load centers with an overall reduction of greenhouses gases is edging closer to reality.« less

40 CFR Table 3 to Subpart Ttttt of... - Initial Compliance With Emission Limits

Code of Federal Regulations, 2011 CFR

2011-07-01

... CATEGORIES (CONTINUED) National Emissions Standards for Hazardous Air Pollutants for Primary Magnesium...), did not exceed 200 lbs/hr. 2. Each magnesium chloride storage bin scrubber stack a. The average mass flow of hydrochloric acid from the control system applied to the magnesium chloride storage bins...

40 CFR Table 3 to Subpart Ttttt of... - Initial Compliance With Emission Limits

Code of Federal Regulations, 2010 CFR

2010-07-01

... CATEGORIES (CONTINUED) National Emissions Standards for Hazardous Air Pollutants for Primary Magnesium...), did not exceed 200 lbs/hr. 2. Each magnesium chloride storage bin scrubber stack a. The average mass flow of hydrochloric acid from the control system applied to the magnesium chloride storage bins...

40 CFR Table 3 to Subpart Ttttt of... - Initial Compliance With Emission Limits

Code of Federal Regulations, 2013 CFR

2013-07-01

... CATEGORIES (CONTINUED) National Emissions Standards for Hazardous Air Pollutants for Primary Magnesium...), did not exceed 200 lbs/hr. 2. Each magnesium chloride storage bin scrubber stack a. The average mass flow of hydrochloric acid from the control system applied to the magnesium chloride storage bins...

40 CFR Table 3 to Subpart Ttttt of... - Initial Compliance With Emission Limits

Code of Federal Regulations, 2012 CFR

2012-07-01

... CATEGORIES (CONTINUED) National Emissions Standards for Hazardous Air Pollutants for Primary Magnesium...), did not exceed 200 lbs/hr. 2. Each magnesium chloride storage bin scrubber stack a. The average mass flow of hydrochloric acid from the control system applied to the magnesium chloride storage bins...

40 CFR 49.129 - Rule for limiting emissions of sulfur dioxide.

Code of Federal Regulations, 2010 CFR

2010-07-01

... emissions from a combustion source stack must not exceed an average of 500 parts per million by volume, on a..., air pollution source, ambient air, British thermal unit (Btu), coal, combustion source, continuous..., incinerator, marine vessel, mobile sources, motor vehicle, nonroad engine, nonroad vehicle, open burning...

40 CFR 49.129 - Rule for limiting emissions of sulfur dioxide.

Code of Federal Regulations, 2011 CFR

2011-07-01

... emissions from a combustion source stack must not exceed an average of 500 parts per million by volume, on a..., air pollution source, ambient air, British thermal unit (Btu), coal, combustion source, continuous..., incinerator, marine vessel, mobile sources, motor vehicle, nonroad engine, nonroad vehicle, open burning...

Battery condenser system particulate emission factors for cotton gins: Particle size distribution characteristics

USDA-ARS?s Scientific Manuscript database

This report is part of a project to characterize cotton gin emissions from the standpoint of total particulate stack sampling and particle size analyses. In 2013, the Environmental Protection Agency (EPA) published a more stringent standard for particulate matter with nominal diameter less than or e...

Device for equalizing molten electrolyte content in a fuel cell stack

DOEpatents

Smith, J.L.

1985-12-23

A device for equalizing the molten electrolyte content throughout the height of a fuel cell stack is disclosed. The device includes a passageway for electrolyte return with electrolyte wettable wicking material in the opposite end portions of the passageway. One end portion is disposed near the upper, negative end of the stack where electrolyte flooding occurs. The second end portion is placed near the lower, positive end of the stack where electrolyte is depleted. Heating means are provided at the upper portion of the passageway to increase electrolyte vapor pressure in the upper wicking material. The vapor is condensed in the lower passageway portion and conducted as molten electrolyte in the lower wick to the positive end face of the stack. An inlet is provided to inject a modifying gas into the passageway and thereby control the rate of electrolyte return.

Device for equalizing molten electrolyte content in a fuel cell stack

DOEpatents

Smith, James L.

1987-01-01

A device for equalizing the molten electrolyte content throughout the height of a fuel cell stack is disclosed. The device includes a passageway for electrolyte return with electrolyte wettable wicking material in the opposite end portions of the passageway. One end portion is disposed near the upper, negative end of the stack where electrolyte flooding occurs. The second end portion is placed near the lower, positive end of the stack where electrolyte is depleted. Heating means are provided at the upper portion of the passageway to increase electrolyte vapor pressure in the upper wicking material. The vapor is condensed in the lower passageway portion and conducted as molten electrolyte in the lower wick to the positive end face of the stack. An inlet is provided to inject a modifying gas into the passageway and thereby control the rate of electrolyte return.

PEM fuel cell bipolar plate material requirements for transportation applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Borup, R.L.; Stroh, K.R.; Vanderborgh, N.E.

1996-04-01

Cost effective bipolar plates are currently under development to help make proton exchange membrane (PEM) fuel cells commercially viable. Bipolar plates separate individual cells of the fuel cell stack, and thus must supply strength, be electrically conductive, provide for thermal control of the fuel stack, be a non-porous materials separating hydrogen and oxygen feed streams, be corrosion resistant, provide gas distribution for the feed streams and meet fuel stack cost targets. Candidate materials include conductive polymers and metal plates with corrosion resistant coatings. Possible metals include aluminium, titanium, iron/stainless steel and nickel.

A fluorescent chemosensor for Zn(II). Exciplex formation in solution and the solid state.

PubMed

Bencini, Andrea; Berni, Emanuela; Bianchi, Antonio; Fornasari, Patrizia; Giorgi, Claudia; Lima, Joao C; Lodeiro, Carlos; Melo, Maria J; de Melo, J Seixas; Parola, Antonio Jorge; Pina, Fernando; Pina, Joao; Valtancoli, Barbara

2004-07-21

The macrocyclic phenanthrolinophane 2,9-[2,5,8-triaza-5-(N-anthracene-9-methylamino)ethyl]-[9]-1,10-phenanthrolinophane (L) bearing a pendant arm containing a coordinating amine and an anthracene group forms stable complexes with Zn(II), Cd(II) and Hg(II) in solution. Stability constants of these complexes were determined in 0.10 mol dm(-3) NMe(4)Cl H(2)O-MeCN (1:1, v/v) solution at 298.1 +/- 0.1 K by means of potentiometric (pH metric) titration. The fluorescence emission properties of these complexes were studied in this solvent. For the Zn(II) complex, steady-state and time-resolved fluorescence studies were performed in ethanol solution and in the solid state. In solution, intramolecular pi-stacking interaction between phenanthroline and anthracene in the ground state and exciplex emission in the excited state were observed. From the temperature dependence of the photostationary ratio (I(Exc)/I(M)), the activation energy for the exciplex formation (E(a)) and the binding energy of the exciplex (-DeltaH) were determined. The crystal structure of the [ZnLBr](ClO(4)).H(2)O compound was resolved, showing that in the solid state both intra- and inter-molecular pi-stacking interactions are present. Such interactions were also evidenced by UV-vis absorption and emission spectra in the solid state. The absorption spectrum of a thin film of the solid complex is red-shifted compared with the solution spectra, whereas its emission spectrum reveals the unique featureless exciplex band, blue shifted compared with the solution. In conjunction with X-ray data the solid-state data was interpreted as being due to a new exciplex where no pi-stacking (full overlap of the pi-electron cloud of the two chromophores - anthracene and phenanthroline) is observed. L is a fluorescent chemosensor able to signal Zn(II) in presence of Cd(II) and Hg(II), since the last two metal ions do not give rise either to the formation of pi-stacking complexes or to exciplex emission in solution.

Life-cycle greenhouse gas emissions of shale gas, natural gas, coal, and petroleum.

PubMed

Burnham, Andrew; Han, Jeongwoo; Clark, Corrie E; Wang, Michael; Dunn, Jennifer B; Palou-Rivera, Ignasi

2012-01-17

The technologies and practices that have enabled the recent boom in shale gas production have also brought attention to the environmental impacts of its use. It has been debated whether the fugitive methane emissions during natural gas production and transmission outweigh the lower carbon dioxide emissions during combustion when compared to coal and petroleum. Using the current state of knowledge of methane emissions from shale gas, conventional natural gas, coal, and petroleum, we estimated up-to-date life-cycle greenhouse gas emissions. In addition, we developed distribution functions for key parameters in each pathway to examine uncertainty and identify data gaps such as methane emissions from shale gas well completions and conventional natural gas liquid unloadings that need to be further addressed. Our base case results show that shale gas life-cycle emissions are 6% lower than conventional natural gas, 23% lower than gasoline, and 33% lower than coal. However, the range in values for shale and conventional gas overlap, so there is a statistical uncertainty whether shale gas emissions are indeed lower than conventional gas. Moreover, this life-cycle analysis, among other work in this area, provides insight on critical stages that the natural gas industry and government agencies can work together on to reduce the greenhouse gas footprint of natural gas.

A Life Cycle Assessment Case Study of Coal-Fired Electricity Generation with Humidity Swing Direct Air Capture of CO2 versus MEA-Based Postcombustion Capture.

PubMed

van der Giesen, Coen; Meinrenken, Christoph J; Kleijn, René; Sprecher, Benjamin; Lackner, Klaus S; Kramer, Gert Jan

2017-01-17

Most carbon capture and storage (CCS) envisions capturing CO 2 from flue gas. Direct air capture (DAC) of CO 2 has hitherto been deemed unviable because of the higher energy associated with capture at low atmospheric concentrations. We present a Life Cycle Assessment of coal-fired electricity generation that compares monoethanolamine (MEA)-based postcombustion capture (PCC) of CO 2 with distributed, humidity-swing-based direct air capture (HS-DAC). Given suitable temperature, humidity, wind, and water availability, HS-DAC can be largely passive. Comparing energy requirements of HS-DAC and MEA-PCC, we find that the parasitic load of HS-DAC is less than twice that of MEA-PCC (60-72 kJ/mol versus 33-46 kJ/mol, respectively). We also compare other environmental impacts as a function of net greenhouse gas (GHG) mitigation: To achieve the same 73% mitigation as MEA-PCC, HS-DAC would increase nine other environmental impacts by on average 38%, whereas MEA-PCC would increase them by 31%. Powering distributed HS-DAC with photovoltaics (instead of coal) while including recapture of all background GHG, reduces this increase to 18%, hypothetically enabling coal-based electricity with net-zero life-cycle GHG. We conclude that, in suitable geographies, HS-DAC can complement MEA-PCC to enable CO 2 capture independent of time and location of emissions and recapture background GHG from fossil-based electricity beyond flue stack emissions.

40 CFR 503.44 - Operational standard-total hydrocarbons.

Code of Federal Regulations, 2012 CFR

2012-07-01

... incinerator shall be corrected for zero percent moisture by multiplying the measured total hydrocarbons... the percent moisture in the sewage sludge incinerator exit gas in hundredths. (b) The total... the exit gas from a sewage sludge incinerator stack, corrected for zero percent moisture using the...

40 CFR 503.44 - Operational standard-total hydrocarbons.

Code of Federal Regulations, 2014 CFR

2014-07-01

... incinerator shall be corrected for zero percent moisture by multiplying the measured total hydrocarbons... the percent moisture in the sewage sludge incinerator exit gas in hundredths. (b) The total... the exit gas from a sewage sludge incinerator stack, corrected for zero percent moisture using the...

40 CFR 503.44 - Operational standard-total hydrocarbons.

Code of Federal Regulations, 2013 CFR

2013-07-01

... incinerator shall be corrected for zero percent moisture by multiplying the measured total hydrocarbons... the percent moisture in the sewage sludge incinerator exit gas in hundredths. (b) The total... the exit gas from a sewage sludge incinerator stack, corrected for zero percent moisture using the...

Effect of forming gas annealing on the degradation properties of Ge-based MOS stacks

NASA Astrophysics Data System (ADS)

Aguirre, F.; Pazos, S.; Palumbo, F. R. M.; Fadida, S.; Winter, R.; Eizenberg, M.

2018-04-01

The influence of forming gas annealing on the degradation at a constant stress voltage of multi-layered germanium-based Metal-Oxide-Semiconductor capacitors (p-Ge/GeOx/Al2O3/High-K/Metal Gate) has been analyzed in terms of the C-V hysteresis and flat band voltage as a function of both negative and positive stress fields. Significant differences were found for the case of negative voltage stress between the annealed and non-annealed samples, independently of the stressing time. It was found that the hole trapping effect decreases in the case of the forming gas annealed samples, indicating strong passivation of defects with energies close to the valence band existing in the oxide-semiconductor interface during the forming gas annealing. Finally, a comparison between the degradation dynamics of Germanium and III-V (n-InGaAs) MOS stacks is presented to summarize the main challenges in the integration of reliable Ge-III-V hybrid devices.

PEM fuel cell monitoring system

DOEpatents

Meltser, M.A.; Grot, S.A.

1998-06-09

Method and apparatus are disclosed for monitoring the performance of H{sub 2}--O{sub 2} PEM fuel cells. Outputs from a cell/stack voltage monitor and a cathode exhaust gas H{sub 2} sensor are corrected for stack operating conditions, and then compared to predetermined levels of acceptability. If certain unacceptable conditions coexist, an operator is alerted and/or corrective measures are automatically undertaken. 2 figs.

A SCUBA-2 850-micron Survey of Circumstellar Disks in the λ Orionis Cluster

NASA Astrophysics Data System (ADS)

Ansdell, Megan; Williams, Jonathan P.; Cieza, Lucas A.

2015-06-01

We present results from an 850 μm survey of the ˜5 Myr old λ Orionis star-forming region. We used the SCUBA-2 camera on the James Clerk Maxwell Telescope to survey a ˜0.°5-diameter circular region containing 36 (out of 59) cluster members with infrared excesses indicative of circumstellar disks. We detected only one object at \\gt 3σ significance, the Herbig Ae star HD 245185, with a flux density of ˜74 mJy beam-1 corresponding to a dust mass of ˜150 {M}\\oplus . Stacking the individually undetected sources did not produce a significant mean signal but gives an upper limit on the average dust mass for λ Orionis disks of ˜3 {M}\\oplus . Our follow-up observations of HD 245185 with the Submillimeter Array found weak CO 2-1 line emission with an integrated flux of ˜170 mJy km s-1 but no 13CO or C18O isotopologue emission at 30 mJy km s-1 sensitivity, suggesting a gas mass of ≲ 1 M{}{Jup}. The implied gas-to-dust ratio is thus ≳ 50 times lower than the canonical interstellar medium value, setting HD 245185 apart from other Herbig Ae disks of similar age, which have been found to be gas rich; as HD 245185 also shows signs of accretion, we may be catching it in the final phases of disk clearing. Our study of the λ Orionis cluster places quantitative constraints on planet formation timescales, indicating that at ˜5 Myr the average disk no longer has sufficient dust and gas to form giant planets and perhaps even super-Earths; the bulk material has been mostly dispersed or is locked in pebbles/planetesimals larger than a few mm in size.

Effects of nitrogen fertilizer application on greenhouse gas emissions and economics of corn production.

PubMed

Kim, Seungdo; Dale, Bruce E

2008-08-15

Nitrogen fertilizer plays an important role in corn cultivation in terms of both economic and environmental aspects. Nitrogen fertilizer positively affects corn yield and the soil organic carbon level, but it also has negative environmental effects through nitrogen-related emissions from soil (e.g., N20, NOx, NO3(-) leaching, etc.). Effects of nitrogen fertilizer on greenhouse gas emissions associated with corn grain are investigated via life cycle assessment. Ecoefficiency analysis is also used to determine an economically and environmentally optimal nitrogen application rate (NAR). The ecoefficiency index in this study is defined as the ratio of economic return due to nitrogen fertilizer to the greenhouse gas emissions of corn cultivation. Greenhouse gas emissions associated with corn grain decrease as NAR increases at a lower NAR until a minimum greenhouse gas emission level is reached because corn yield and soil organic carbon level increase with NAR. Further increasing NAR after a minimum greenhouse gas emission level raises greenhouse gas emissions associated with corn grain. Increased greenhouse gas emissions of corn grain due to nitrous oxide emissions from soil are much higher than reductions of greenhouse gas emissions of corn grain due to corn yield and changes in soil organic carbon levels at a higher NAR. Thus, there exists an environmentally optimal NAR in terms of greenhouse gas emissions. The trends of the ecoefficiency index are similar to those of economic return to nitrogen and greenhouse gas emissions associated with corn grain. Therefore, an appropriate NAR could enhance profitability as well as reduce greenhouse gas emissions associated with corn grain.

Characterization of Air Toxics from an Oil-Fired Firetube Boiler.

PubMed

Miller, C Andrew; Ryan, Jeffrey V; Lombardo, Tony

1996-08-01

Tests were conducted on a commercially available firetube package boiler running on #2 through #6 oils to determine the emissions levels of hazardous air pollutants from the combustion of four fuel oils (a #2 oil, a #5 oil, a low sulfur #6 oil, and a high sulfur #6 oil). Measurements of carbon monoxide, nitrogen oxides, particulate matter, and sulfur dioxide stack gas concentrations were made for each oil. Flue gases were also sampled to determine levels of volatile and semivolatile organic compounds and of metals. Analytical procedures were used to provide more detailed information regarding the emissions rates for carbonyls (aldehydes and ketones), and polycyclic aromatic hydrocarbons (PAHs) in addition to the standard analyses for volatile and semivolatile organics. Metals emissions were greater than organic emissions for all oils tested, by an order of magnitude. Carbonyls dominated the organic emissions, with emission rates more than double the remaining organics for all four oils tested. Formaldehyde made up the largest percentage of carbonyls, at roughly 50% of these emissions for three of the four oils, and approximately 30% of the carbonyl emissions from the low sulfur #6 oil. Naphthalene was found to be the largest part of the PAH emissions for three of the four oils, with phenanthrene being greatest for the #2 fuel oil. The flue gases were also sampled for polychlorinated dibenzodioxins and polychlorinated dibenzofurans; however, inconsistent levels were found between repeat tests. For the boiler tested, no single hazardous air pollutant (HAP) was emitted at a rate which would require control under Title III of the Clean Air Act Amendments of 1990. The fuel emitting the largest amount of HAPs was the high sulfur #6 oil, which had a total HAP emission rate of less than 100 lb (45 kg)/year, based on operation for a full year at a firing rate of 1.25 x 106 Btu/hr (50% load of the unit tested).

Purex Plant comparison with 40 CFR 61, subpart H, and other referenced guidelines for the Product Removal (PR) (296-A-1) stack

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lohrasbi, J.

Dose calculations for atmospheric radionuclide releases from the Hanford Site for calendar year (CY) 1992 were performed by Pacific Northwest Laboratory (PNL) using the approved US Environmental Protection Agency (EPA) CAP-88 computer model. Emissions from discharge points in the Hanford Site 100, 200, 300, 400, and 600 areas were calculated based on results of analyses of continuous and periodic sampling conducted at the discharge points. These calculated emissions were provided for inclusion in the CAP-88 model by area and by individual facility for those facilities having the potential to contribute more than 10 percent of the Hanford Site total ormore » to result in an impact of greater than 0.1 mrem per year to the maximally exposed individual (MEI). Also included in the assessment of offsite dose modeling are the measured radioactive emissions from all Hanford Site stacks that have routine monitoring performed. Record sampling systems have been installed on all stacks and vents that use exhaust fans to discharge air that potentially may carry airborne radioactivity. Estimation of activity from ingrowth of long-lived radioactive progeny is not included in the CAP-88 model; therefore, the Hanford Site GENII code (Napier et al. 1988) was used to supplement the CAP-88 dose calculations. When the dose to the MEI located in the Ringold area was calculated, the effective dose equivalent (EDE) from combined Hanford Site radioactive airborne emissions was shown to be 3.7E-03 mrem. This value was reported in the annual air emission report prepared for the Hanford Site (RL 1993).« less

High Temperature Electrolysis Pressurized Experiment Design, Operation, and Results

DOE Office of Scientific and Technical Information (OSTI.GOV)

J.E. O'Brien; X. Zhang; G.K. Housley

2012-09-01

A new facility has been developed at the Idaho National Laboratory for pressurized testing of solid oxide electrolysis stacks. Pressurized operation is envisioned for large-scale hydrogen production plants, yielding higher overall efficiencies when the hydrogen product is to be delivered at elevated pressure for tank storage or pipelines. Pressurized operation also supports higher mass flow rates of the process gases with smaller components. The test stand can accommodate planar cells with dimensions up to 8.5 cm x 8.5 cm and stacks of up to 25 cells. It is also suitable for testing other cell and stack geometries including tubular cells.more » The pressure boundary for these tests is a water-cooled spool-piece pressure vessel designed for operation up to 5 MPa. Pressurized operation of a ten-cell internally manifolded solid oxide electrolysis stack has been successfully demonstrated up 1.5 MPa. The stack is internally manifolded and operates in cross-flow with an inverted-U flow pattern. Feed-throughs for gas inlets/outlets, power, and instrumentation are all located in the bottom flange. The entire spool piece, with the exception of the bottom flange, can be lifted to allow access to the internal furnace and test fixture. Lifting is accomplished with a motorized threaded drive mechanism attached to a rigid structural frame. Stack mechanical compression is accomplished using springs that are located inside of the pressure boundary, but outside of the hot zone. Initial stack heatup and performance characterization occurs at ambient pressure followed by lowering and sealing of the pressure vessel and subsequent pressurization. Pressure equalization between the anode and cathode sides of the cells and the stack surroundings is ensured by combining all of the process gases downstream of the stack. Steady pressure is maintained by means of a backpressure regulator and a digital pressure controller. A full description of the pressurized test apparatus is provided in this report. Results of initial testing showed the expected increase in open-cell voltage associated with elevated pressure. However, stack performance in terms of area-specific resistance was enhanced at elevated pressure due to better gas diffusion through the porous electrodes of the cells. Some issues such as cracked cells and seals were encountered during testing. Full resolution of these issues will require additional testing to identify the optimum test configurations and protocols.« less

Method of preparing a dimensionally stable electrode for use in a molten carbonate fuel cell

DOEpatents

Swarr, T.E.; Wnuck, W.G.

1986-01-29

A method is disclosed for preparing a dimensionally stable electrode structure, particularly nickel-chromium anodes, for use in a molten carbonate fuel cell stack. A low-chromium to nickel alloy is provided and oxidized in a mildly oxidizing gas of sufficient oxidation potential to oxidize chromium in the alloy structure. Typically, a steam/H/sub 2/ gas mixture in a ratio of about 100/1 and at a temperature below 800/sup 0/C is used as the oxidizing medium. This method permits the use of less than 5 wt % chromium in nickel alloy electrodes while obtaining good resistance to creep in the electrodes of a fuel cell stack.

Method of preparing a dimensionally stable electrode for use in a MCFC

DOEpatents

Swarr, Thomas E.; Wnuck, Wayne G.

1987-12-22

A method is disclosed for preparing a dimensionally stable electrode structure, particularly nickel-chromium anodes, for use in a molten carbonate fuel cell stack. A low-chromium to nickel alloy is provided and oxidized in a mildly oxidizing gas of sufficient oxidation potential to oxidize chromium in the alloy structure. Typically, a steam/H.sub.2 gas mixture in a ratio of about 100/1 and at a temperature below 800.degree. C. is used as the oxidizing medium. This method permits the use of less than 5 weight percent chromium in nickel alloy electrodes while obtaining good resistance to creep in the electrodes of a fuel cell stack.

Experimental Determination of Exhaust Gas Thrust, Special Report

NASA Technical Reports Server (NTRS)

Pinkel, Benjamin; Voss, Fred

1940-01-01

This investigation presents the results of tests made on a radial engine to determine the thrust that can be obtained from the exhaust gas when discharged from separate stacks and when discharged from the collector ring with various discharge nozzles. The engine was provided with a propeller to absorb the power and was mounted on a test stand equipped with scales for measuring the thrust and engine torque. The results indicate that at full open throttle at sea level, for the engine tested, a gain in thrust horsepower of 18 percent using separate stacks, and 9.5 percent using a collector ring and discharge nozzle, can be expected at an air speed of 550 miles per hour.

The Relation between [O III]/Hβ and Specific Star Formation Rate in Galaxies at z ˜ 2

NASA Astrophysics Data System (ADS)

Dickey, Claire Mackay; van Dokkum, Pieter G.; Oesch, Pascal A.; Whitaker, Katherine E.; Momcheva, Ivelina G.; Nelson, Erica J.; Leja, Joel; Brammer, Gabriel B.; Franx, Marijn; Skelton, Rosalind E.

2016-09-01

Recent surveys have identified a seemingly ubiquitous population of galaxies with elevated [O III]/Hβ emission line ratios at z > 1, although the nature of this phenomenon continues to be debated. The [O III]/Hβ line ratio is of interest because it is a main component of the standard diagnostic tools used to differentiate between active galactic nuclei and star-forming galaxies as well as the gas-phase metallicity indicators O 23 and R 23. Here, we investigate the primary driver of increased [O III]/Hβ ratios by median-stacking rest-frame optical spectra for a sample of star-forming galaxies in the 3D-HST survey in the redshift range z ˜ 1.4-2.2. Using N = 4220 star-forming galaxies, we stack the data in bins of mass and specific star formation rates (sSFRs), respectively. After accounting for stellar Balmer absorption, we measure [O III]λ5007 Å/Hβ down to M ˜ 109.2 M ⊙ and sSFR ˜ 10-9.6 yr-1, greater than an order of magnitude lower than previous work at similar redshifts. We find an offset of 0.59 ± 0.05 dex between the median ratios at z ˜ 2 and z ˜ 0 at fixed stellar mass, in agreement with existing studies. However, with respect to sSFR, the z ˜ 2 stacks all lie within 1σ of the median SDSS ratios, with an average offset of only -0.06 ± 0.05. We find that the excitation properties of galaxies are tightly correlated with their sSFR at both z ˜ 2 and z ˜ 0, with a relation that appears to be roughly constant over the last 10 Gyr of cosmic time.

Advanced measurement techniques to characterize thermo-mechanical aspects of solid oxide fuel cells

NASA Astrophysics Data System (ADS)

Malzbender, J.; Steinbrech, R. W.

Advanced characterization methods have been used to analyze the thermo-mechanical behaviour of solid oxide fuel cells in a model stack. The primarily experimental work included contacting studies, sealing of a model stack, thermal and re-oxidation cycling. Also an attempt was made to correlate cell fracture in the stack with pore sizes determined from computer tomography. The contacting studies were carried out using pressure sensitive foils. The load to achieve full contact on anode and cathode side of the cell was assessed and applied in the subsequent model stack test. The stack experiment permitted a detailed analysis of stack compaction during sealing. During steady state operation thermal and re-oxidation cycling the changes in open cell voltage and acoustic emissions were monitored. Significant softening of the sealant material was observed at low temperatures. Heating in the thermal cycling loop of the stack appeared to be less critical than the cooling. Re-oxidation cycling led to significant damage if a critical re-oxidation time was exceeded. Microstructural studies permitted further insight into the re-oxidation mechanism. Finally, the maximum defect size in the cell was determined by computer tomography. A limit of maximum anode stress was estimated and the result correlated this with the failure strength observed during the model stack testing.

40 CFR 264.345 - Operating requirements.

Code of Federal Regulations, 2010 CFR

2010-07-01

... variations in the physical or chemical properties of the waste feed which will not affect compliance with the... (CO) level in the stack exhaust gas; (2) Waste feed rate; (3) Combustion temperature; (4) An appropriate indicator of combustion gas velocity; (5) Allowable variations in incinerator system design or...

Synthesis of carbon nanotubes from palm oil on stacking and non-stacking substrate by thermal-CVD method

NASA Astrophysics Data System (ADS)

Robaiah, M.; Rusop, M.; Abdullah, S.; Khusaimi, Z.; Azhan, H.; Fadzlinatul, M. Y.; Salifairus, M. J.; Asli, N. A.

2018-05-01

Palm oil has been used as the carbon source to synthesize carbon nanotubes (CNTs) on silicon substrates using the thermal chemical vapor deposition (CVD) method. Meanwhile, silicon has been applied using two techniques, which are stacked technique and non-stacked technique. The CNTs were grown at the constant time of 30 minutes with various synthesis temperatures of 750 °C, 850 °C and 950 °C. The CNTs were characterized using micro-Raman spectroscopy and field emission scanning electron microscopy (FESEM). It was found that the density, growth rate, diameter and length of the CNTs produced were affected by the synthesis temperature. Moreover, the structure slightly changes were observed between CNTs obtained in SS and NSS. The synthesize temperature of 750 °C was considered as the suitable temperature for the production of CNTs due to low ID/IG ratio, which for stacked is 0.89 and non-stacked are 0.90. The possible explanation for the different morphology of the produced CNTs was also discussed.

Processing of aerosol particles within the Habshan pollution plume

NASA Astrophysics Data System (ADS)

Semeniuk, T. A.; Bruintjes, R.; Salazar, V.; Breed, D.; Jensen, T.; Buseck, P. R.

2015-03-01

The Habshan industrial site in the United Arab Emirates produces a regional-scale pollution plume associated with oil and gas processing, discharging high loadings of sulfates and chlorides into the atmosphere, which interact with the ambient aerosol population. Aerosol particles and trace gas chemistry at this site were studied on two flights in the summer of 2002. Measurements were collected along vertical plume profiles to show changes associated with atmospheric processing of particle and gas components. Close to the outlet stack, particle concentrations were over 10,000 cm-3, dropping to <2000 cm-3 in more dilute plume around 1500 m above the stack. Particles collected close to the stack and within the dilute plume were individually measured for size, morphology, composition, and mixing state using transmission electron microscopy coupled with energy-dispersive X-ray spectroscopy. Close to the stack, most coarse particles consisted of mineral dust and NaCl crystals from burning oil brines, while sulfate droplets dominated the fine mode. In more dilute plume, at least 1500 m above the stack, the particle spectrum was more diverse, with a significant increase in internally mixed particle types. Dilute plume samples consisted of coarse NaCl/silicate aggregates or NaCl-rich droplets, often with a sulfate component, while fine-fraction particles were of mixed cation sulfates, also internally mixed with nanospherical soot or silicates. Thus, both chloride and sulfate components of the pollution plume rapidly reacted with ambient mineral dust to form coated and aggregate particles, enhancing particle size, hygroscopicity, and reactivity of the coarse mode. The fine-fraction sulfate-bearing particles formed in the plume contribute to regional transport of sulfates, while coarse sulfate-bearing fractions locally reduced the SO2 loading through sedimentation. The chloride- and sulfate-bearing internally mixed particles formed in the plume markedly changed the reflectivity and scattering properties of the ambient aerosol population, as well as its hygroscopic and ice nucleation properties.

Stacking fault related luminescence in GaN nanorods.

PubMed

Forsberg, M; Serban, A; Poenaru, I; Hsiao, C-L; Junaid, M; Birch, J; Pozina, G

2015-09-04

Optical and structural properties are presented for GaN nanorods (NRs) grown in the [0001] direction on Si(111) substrates by direct-current reactive magnetron sputter epitaxy. Transmission electron microscopy (TEM) reveals clusters of dense stacking faults (SFs) regularly distributed along the c-axis. A strong emission line at ∼3.42 eV associated with the basal-plane SFs has been observed in luminescence spectra. The optical signature of SFs is stable up to room temperatures with the activation energy of ∼20 meV. Temperature-dependent time-resolved photoluminescence properties suggest that the recombination mechanism of the 3.42 eV emission can be understood in terms of multiple quantum wells self-organized along the growth axis of NRs.

Hydrogen gas relief valve

DOEpatents

Whittlesey, Curtis C.

1985-01-01

An improved battery stack design for an electrochemical system having at least one cell from which a gas is generated and an electrolyte in communication with the cell is described. The improved battery stack design features means for defining a substantially closed compartment for containing the battery cells and at least a portion of the electrolyte for the system, and means in association with the compartment means for selectively venting gas from the interior of the compartment means in response to the level of the electrolyte within the compartment means. The venting means includes a relief valve having a float member which is actuated in response to the level of the electrolyte within the compartment means. This float member is adapted to close the relief valve when the level of the electrolyte is above a predetermined level and open the relief valve when the level of electrolyte is below this predetermined level.

Directional Thermal Emission and Absorption from Surface Microstructures in Metalized Plastics

DTIC Science & Technology

2013-09-01

conductive surfaces for directional emission is presented. First, key accomplishments in exploiting surface plasmons for coherent thermal emission from...than as an absorbing coating . In the 2005 design proposed by Lee et al., thermally excited surface waves at a silicon carbide to photonic crystal stack...sufficiently to significantly effect the film durability and thermal conductivity , the profile of the cavity begins to change shape. Although a case

40 CFR 60.1400 - What must I include in my initial report?

Code of Federal Regulations, 2010 CFR

2010-07-01

... parameters (use appropriate units as specified in table 2 of this subpart): (1) Dioxins/furans. (2) Cadmium... stack test for dioxins/furans emissions and include supporting calculations. (f) If your municipal waste combustion unit uses activated carbon to control dioxins/furans or mercury emissions, the average carbon feed...

40 CFR 60.1305 - May I conduct stack testing less often?

Code of Federal Regulations, 2010 CFR

2010-07-01

...: dioxins/furans, cadmium, lead, mercury, particulate matter, opacity, hydrogen chloride, and fugitive ash. (b) You can test less often for dioxins/furans emissions if you own or operate a municipal waste... levels of dioxins/furans emissions less than or equal to 7 nanograms per dry standard cubic meter (total...

Battery condenser system PM2.5 emission factors and rates for cotton gins

USDA-ARS?s Scientific Manuscript database

This manuscript is part of a series of manuscripts that detail a project to characterize cotton gin emissions from the standpoint of stack and ambient sampling. The impetus behind the project was the 2006 EPA implementation of a more stringent standard for particulate matter less than or equal to 2....

Nitrogen oxides from waste incineration: control by selective non-catalytic reduction.

PubMed

Zandaryaa, S; Gavasci, R; Lombardi, F; Fiore, A

2001-01-01

An experimental study of the selective non-catalytic reduction (SNCR) process was carried out to determine the efficiency of NOx removal and NH3 mass balance, the NOx reducing reagent used. Experimental tests were conducted on a full-scale SNCR system installed in a hospital waste incineration plant. Anhydrous NH3 was injected at the boiler entrance for NOx removal. Ammonia was analyzed after each flue-gas treatment unit in order to establish its mass balance and NH3 slip in the stack gas was monitored as well. The effective fraction of NH3 for the thermal NOx reduction was calculated from measured values of injected and residual NH3. Results show that a NOx reduction efficiency in the range of 46.7-76.7% is possible at a NH3/NO molar ratio of 0.9-1.5. The fraction of NH3 used in NOx removal was found to decrease with rising NH3/NO molar ratio. The NH3 slip in the stack gas was very low, below permitted limits, even at the higher NH3 dosages used. No direct correlation was found between the NH3/NO molar ratio and the NH3 slip in the stack gas since the major part of the residual NH3 was converted into ammonium salts in the dry scrubbing reactor and subsequently collected in the fabric filter. Moreover, another fraction of NH3 was dissolved in the scrubbing liquor.

Edge functionalised & Li-intercalated 555-777 defective bilayer graphene for the adsorption of CO2 and H2O

NASA Astrophysics Data System (ADS)

Lalitha, Murugan; Lakshmipathi, Senthilkumar; Bhatia, Suresh K.

2017-04-01

The adsorption of CO2 and H2O on divacanacy (DV) defected graphene cluster, and its bilayer counterpart is investigated using first-principles calculations. Both single and bilayer DV graphene cluster, are functionalised with H and F atoms. On these sheets the gas molecules are physisorbed, and the divacancy defect effectively improves the adsorption of CO2, while fluorination enhances the hydrophobicity of the graphene cluster. Among the convex and concave curvature regions induced due to the DV defect, the adsorption of the gas molecules on the concave meniscus is more favourable. Fluorine termination induces 73% reduction in Henry law constants for H2O, while for the CO2 molecule it increases by 8%, which indicates the DV defective sheet is a better candidate for CO2 capture compared to the STW defective sheet. Besides, both AA and AB divacant defect bilayer sheets are equally stable, wherein AA stacking results in a cavity between the sheets, while in AB stacking, the layers slide one over the other. Nevertheless, both these bilayer sheets are comparatively stabler than the monolayer. However, intercalation of lithium decreases the interlayer separation, particularly in AA stacking, which enhances the CO2 adsorption, but in the Bernal stacking enhances it hydrophobicity.

Coal-Fired Boilers at Navy Bases, Navy Energy Guidance Study, Phase II and III.

DTIC Science & Technology

1979-05-01

several sizes were performed. Central plants containing four equal-sized boilers and central flue gas desulfurization facilities were shown to be less...Conceptual design and parametric cost studies of steam and power generation systems using coal-fired stoker boilers and stack gas scrubbers in

DETECTION OF MERCURIC BROMIDE IN A GAS PHASE FLOW CELL BY LASER PHOTOFRAGMENT FLUORESCENCE SPECTROSCOPY. (R825380)

EPA Science Inventory

Photofragment fluorescence (PFF) spectroscopy offers real-time monitoring
capability with high-analytical sensitivity and selectivity for volatile mercury
compounds found in process gas streams, such as incinerator stacks. In this
work, low concentrations (6 ppb to...

Suzuki segregation in a binary Cu-Si alloy.

PubMed

Mendis, Budhika G; Jones, Ian P; Smallman, Raymond E

2004-01-01

Suzuki segregation to stacking faults and coherent twin boundaries has been investigated in a Cu-7.15 at.% Si alloy, heat-treated at temperatures of 275, 400 and 550 degrees C, using field-emission gun transmission electron microscopy. Silicon enrichment was observed at the stacking fault plane and decreased monotonically with increasing annealing temperature. This increase in the concentration of solute at the fault is due to the stacking fault energy being lowered at higher values of the electron-to-atom ratio of the alloy. From a McLean isotherm, the binding energy for segregation was calculated to be -0.021 +/- 0.019 eV atom(-1). Hardly any segregation was observed to coherent twin boundaries in the same alloy. This is because a twin has a lower interfacial energy than a stacking fault, so that the driving force for segregation is diminished.

Study on component interface evolution of a solid oxide fuel cell stack after long term operation

NASA Astrophysics Data System (ADS)

Yang, Jiajun; Huang, Wei; Wang, Xiaochun; Li, Jun; Yan, Dong; Pu, Jian; Chi, Bo; Li, Jian

2018-05-01

A 5-cell solid oxide fuel cell (SOFC) stack with external manifold structure is assembled and underwent a durability test with an output of 250 W for nearly 4400 h when current density and operating temperature are 355 mA/cm2 and 750 °C. Cells used in the stack are anode-supported cells (ASC) with yttria-stabilized zirconia (YSZ) electrolytes, Ni/YSZ hydrogen electrodes, and YSZ based composite cathode. The dimension of the cell is 150 × 150 mm (active area: 130 × 130 mm). Ceramic-glass sealant is used in the stack to keep the gas tightness between cells, interconnects and manifolds. Pure hydrogen and dry air are used as fuel and oxidant respectively. The stack has a maximum output of 340 W at 562 mA/cm2 current density at 750 °C. The stack shows a degradation of 1.5% per 1000 h during the test with 2 thermal cycles to room temperature. After the test, the stack was dissembled and examined. The relationship between microstructure changes of interfaces and degradation in the stack are discussed. The microstructure evolution of interfaces between electrode, contact material and current collector are unveiled and their relationship with the degradation is discussed.

Solid oxide fuel cell generator with removable modular fuel cell stack configurations

DOEpatents

Gillett, J.E.; Dederer, J.T.; Zafred, P.R.; Collie, J.C.

1998-04-21

A high temperature solid oxide fuel cell generator produces electrical power from oxidation of hydrocarbon fuel gases such as natural gas, or conditioned fuel gases, such as carbon monoxide or hydrogen, with oxidant gases, such as air or oxygen. This electrochemical reaction occurs in a plurality of electrically connected solid oxide fuel cells bundled and arrayed in a unitary modular fuel cell stack disposed in a compartment in the generator container. The use of a unitary modular fuel cell stack in a generator is similar in concept to that of a removable battery. The fuel cell stack is provided in a pre-assembled self-supporting configuration where the fuel cells are mounted to a common structural base having surrounding side walls defining a chamber. Associated generator equipment may also be mounted to the fuel cell stack configuration to be integral therewith, such as a fuel and oxidant supply and distribution systems, fuel reformation systems, fuel cell support systems, combustion, exhaust and spent fuel recirculation systems, and the like. The pre-assembled self-supporting fuel cell stack arrangement allows for easier assembly, installation, maintenance, better structural support and longer life of the fuel cells contained in the fuel cell stack. 8 figs.

Solid oxide fuel cell generator with removable modular fuel cell stack configurations

DOEpatents

Gillett, James E.; Dederer, Jeffrey T.; Zafred, Paolo R.; Collie, Jeffrey C.

1998-01-01

A high temperature solid oxide fuel cell generator produces electrical power from oxidation of hydrocarbon fuel gases such as natural gas, or conditioned fuel gases, such as carbon monoxide or hydrogen, with oxidant gases, such as air or oxygen. This electrochemical reaction occurs in a plurality of electrically connected solid oxide fuel cells bundled and arrayed in a unitary modular fuel cell stack disposed in a compartment in the generator container. The use of a unitary modular fuel cell stack in a generator is similar in concept to that of a removable battery. The fuel cell stack is provided in a pre-assembled self-supporting configuration where the fuel cells are mounted to a common structural base having surrounding side walls defining a chamber. Associated generator equipment may also be mounted to the fuel cell stack configuration to be integral therewith, such as a fuel and oxidant supply and distribution systems, fuel reformation systems, fuel cell support systems, combustion, exhaust and spent fuel recirculation systems, and the like. The pre-assembled self-supporting fuel cell stack arrangement allows for easier assembly, installation, maintenance, better structural support and longer life of the fuel cells contained in the fuel cell stack.

Performance Analysis of Air Breathing Proton Exchange Membrane Fuel Cell Stack (PEMFCS) At Different Operating Condition

NASA Astrophysics Data System (ADS)

Sunil, V.; Venkata siva, G.; Yoganjaneyulu, G.; Ravikumar, V. V.

2017-08-01

The answer for an emission free power source in future is in the form of fuel cells which combine hydrogen and oxygen producing electricity and a harmless by product-water. A proton exchange membrane (PEM) fuel cell is ideal for automotive applications. A single cell cannot supply the essential power for any application. Hence PEM fuel cell stacks are used. The effect of different operating parameters namely: type of convection, type of draught, hydrogen flow rate, hydrogen inlet pressure, ambient temperature and humidity, hydrogen humidity, cell orientation on the performance of air breathing PEM fuel cell stack was analyzed using a computerized fuel cell test station. Then, the fuel cell stack was subjected to different load conditions. It was found that the stack performs very poorly at full capacity (runs only for 30 min. but runs for 3 hours at 50% capacity). Hence, a detailed study was undertaken to maximize the duration of the stack’s performance at peak load.