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Sample records for catalytic nox removal

  1. Sulfate Promoted Zirconia as Promising Alkali-Resistant Support for Catalytic NOx Removal

    DEFF Research Database (Denmark)

    Due-Hansen, Johannes; Kustov, Arkadii; Christensen, Claus H.

    is the most efficient method to eliminate NOx from flue gases in stationary sources. The traditional SCR catalyst suffers significant deactivation with time due to the presence of relative large amounts of potassium in bio-fuels. A possible solution to this problem is use of highly acidic supports, which......The use of bio-fuels as alternatives to traditional fossil fuels has attracted much attention recent years since bio-fuels belong to a family of renewable types of energy sources and do not contribute to the green-house effect. Selective catalytic reduction (SCR) of NOx with ammonia as reductant...

  2. A new 3DOM Ce-Fe-Ti material for simultaneously catalytic removal of PM and NOx from diesel engines.

    Science.gov (United States)

    Cheng, Ying; Liu, Jian; Zhao, Zhen; Song, Weiyu; Wei, Yuechang

    2018-01-15

    A new 3DOM material was designed and synthesized for the simultaneous removal of PM (soot particulates) and NOx from diesel engine exhausts. The catalytic purification taking place over the material with double efficacy is cost-efficient. The contact between solid PM and catalyst active site has been process intensified by 3DOM unique structure. 3DOM Ce 0.7 Fe 0.2 Ti 0.1 O 2 catalyst possess a high SCR activity and an excellent selectivity to N 2 , giving a maximum concentration of CO 2 at 385°C for PM combustion and 100% NO conversion in the temperature range of 281-425°C. The dual redox cycles (Fe 3+ +Ce 3+ ↔Fe 2+ +Ce 4+ ,Fe 3+ +Ti 3+ ↔Fe 2+ +Ti 4+ ) and the excellent reducibility and sufficient acid sites of catalysts play key roles for the highly catalytic performance. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Sulfated Zirconia as Alkali-Resistant Support for Catalytic NOx Removal

    DEFF Research Database (Denmark)

    is the most efficient method to eliminate NOx from flue gases in stationary sources. The traditional SCR catalyst suffers significant deactivation with time due to the presence of larger amounts of potassium in bio-fuels. A possible solution of this problem is use of highly acidic supports which would...

  4. Simultaneous Removal of NOx and Mercury in Low Temperature Selective Catalytic and Adsorptive Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Neville G. Pinto; Panagiotis G. Smirniotis

    2006-03-31

    The results of a 18-month investigation to advance the development of a novel Low Temperature Selective Catalytic and Adsorptive Reactor (LTSCAR), for the simultaneous removal of NO{sub x} and mercury (elemental and oxidized) from flue gases in a single unit operation located downstream of the particulate collectors, are reported. In the proposed LTSCAR, NO{sub x} removal is in a traditional SCR mode but at low temperature, and, uniquely, using carbon monoxide as a reductant. The concomitant capture of mercury in the unit is achieved through the incorporation of a novel chelating adsorbent. As conceptualized, the LTSCAR will be located downstream of the particulate collectors (flue gas temperature 140-160 C) and will be similar in structure to a conventional SCR. That is, it will have 3-4 beds that are loaded with catalyst and adsorbent allowing staged replacement of catalyst and adsorbent as required. Various Mn/TiO{sub 2} SCR catalysts were synthesized and evaluated for their ability to reduce NO at low temperature using CO as the reductant. It has been shown that with a suitably tailored catalyst more than 65% NO conversion with 100% N{sub 2} selectivity can be achieved, even at a high space velocity (SV) of 50,000 h-1 and in the presence of 2 v% H{sub 2}O. Three adsorbents for oxidized mercury were developed in this project with thermal stability in the required range. Based on detailed evaluations of their characteristics, the mercaptopropyltrimethoxysilane (MPTS) adsorbent was found to be most promising for the capture of oxidized mercury. This adsorbent has been shown to be thermally stable to 200 C. Fixed-bed evaluations in the targeted temperature range demonstrated effective removal of oxidized mercury from simulated flue gas at very high capacity ({approx}>58 mg Hg/g adsorbent). Extension of the capability of the adsorbent to elemental mercury capture was pursued with two independent approaches: incorporation of a novel nano-layer on the surface of the

  5. HYBRID SELECTIVE NON-CATALYTIC REDUCTION (SNCR)/SELECTIVE CATALYTIC REDUCTION (SCR) DEMONSTRATION FOR THE REMOVAL OF NOx FROM BOILER FLUE GASES; FINAL

    International Nuclear Information System (INIS)

    Jerry B. Urbas

    1999-01-01

    The U. S. Department of Energy (DOE), Electric Power Research Institute (EPRI), Pennsylvania Electric Energy Research Council, (PEERC), New York State Electric and Gas and GPU Generation, Inc. jointly funded a demonstration to determine the capabilities for Hybrid SNCR/SCR (Selective Non-Catalytic Reduction/Selective Catalytic Reduction) technology. The demonstration site was GPU Generation's Seward Unit No.5 (147MW) located in Seward Pennsylvania. The demonstration began in October of 1997 and ended in December 1998. DOE funding was provided through Grant No. DE-FG22-96PC96256 with T. J. Feeley as the Project Manager. EPRI funding was provided through agreements TC4599-001-26999 and TC4599-002-26999 with E. Hughes as the Project Manager. This project demonstrated the operation of the Hybrid SNCR/SCR NO(sub x) control process on a full-scale coal fired utility boiler. The hybrid technology was expected to provide a cost-effective method of reducing NO(sub x) while balancing capital and operation costs. An existing urea based SNCR system was modified with an expanded-duct catalyst to provide increased NO(sub x) reduction efficiency from the SNCR while producing increased ammonia slip levels to the catalyst. The catalyst was sized to reduce the ammonia slip to the air heaters to less than 2 ppm while providing equivalent NO(sub x) reductions. The project goals were to demonstrate hybrid technology is capable of achieving at least a 55% reduction in NO(sub x) emissions while maintaining less than 2ppm ammonia slip to the air heaters, maintain flyash marketability, verify the cost benefit and applicability of Hybrid post combustion technology, and reduce forced outages due to ammonium bisulfate (ABS) fouling of the air heaters. Early system limitations, due to gas temperature stratification, restricted the Hybrid NO(sub x) reduction capabilities to 48% with an ammonia slip of 6.1 mg/Nm(sup 3) (8 ppm) at the catalyst inlet. After resolving the stratification problem

  6. Hydrogen Peroxide Enhances Removal of NOx from Flue Gases

    Science.gov (United States)

    Collins, Michelle M.

    2005-01-01

    Pilot scale experiments have demonstrated a method of reducing the amounts of oxides of nitrogen (NOx) emitted by industrial boilers and powerplant combustors that involves (1) injection of H2O2 into flue gases and (2) treatment of the flue gases by caustic wet scrubbing like that commonly used to remove SO2 from combustion flue gases. Heretofore, the method most commonly used for removing NOx from flue gases has been selective catalytic reduction (SCR), in which the costs of both installation and operation are very high. After further development, the present method may prove to be an economically attractive alternative to SCR.

  7. Catalytic performance of Ag/Al2O3-C2H5OH-Cu/Al2O3 system for the removal of NOx from diesel engine exhaust.

    Science.gov (United States)

    Zhang, Changbin; He, Hong; Shuai, Shijin; Wang, Jianxin

    2007-05-01

    The selective catalytic reduction (SCR) of NOx by C(2)H(5)OH was studied in excess oxygen over Ag/Al(2)O(3) catalysts with different Ag loadings at lab conditions. The 4% Ag/Al(2)O(3) has the highest activity for the C(2)H(5)OH-SCR of NOx with a drawback of simultaneously producing CO and unburned THC in effluent gases. An oxidation catalyst 10% Cu/Al(2)O(3) was directly placed after the Ag/Al(2)O(3) to remove CO and unburned THC. Washcoated honeycomb catalysts were prepared based on the 4% Ag/Al(2)O(3) and 10% Cu/Al(2)O(3) powders and tested for the C(2)H(5)OH-SCR of NOx on a diesel engine at the practical operating conditions. Compared with the Ag/Al(2)O(3) powder, the Ag/Al(2)O(3) washcoated honeycomb catalyst (SCR catalyst) has a similar activity for NOx reduction by C(2)H(5)OH and the drawback of increasing the CO and unburned THC emissions. Using the SCR+Oxi composite catalyst with the optimization of C(2)H(5)OH addition, the diesel engine completely meets EURO III emission standards.

  8. Integrated Removal of NOx with Carbon Monoxide as Reductant, and Capture of Mercury in a Low Temperature Selective Catalytic and Adsorptive Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Neville Pinto; Panagiotis Smirniotis; Stephen Thiel

    2010-08-31

    Coal will likely continue to be a dominant component of power generation in the foreseeable future. This project addresses the issue of environmental compliance for two important pollutants: NO{sub x} and mercury. Integration of emission control units is in principle possible through a Low Temperature Selective Catalytic and Adsorptive Reactor (LTSCAR) in which NO{sub x} removal is achieved in a traditional SCR mode but at low temperature, and, uniquely, using carbon monoxide as a reductant. The capture of mercury is integrated into the same process unit. Such an arrangement would reduce mercury removal costs significantly, and provide improved control for the ultimate disposal of mercury. The work completed in this project demonstrates that the use of CO as a reductant in LTSCR is technically feasible using supported manganese oxide catalysts, that the simultaneous warm-gas capture of elemental and oxidized mercury is technically feasible using both nanostructured chelating adsorbents and ceria-titania-based materials, and that integrated removal of mercury and NO{sub x} is technically feasible using ceria-titania-based materials.

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

    Science.gov (United States)

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

  10. Simultaneous Elimination of Soot and NOX through Silver-Barium Based Catalytic Materials

    Directory of Open Access Journals (Sweden)

    Ganesh Chandra Dhal

    2017-04-01

    Full Text Available In this research paper, the nanometric size effect, the effects of the intrinsic factors including structure, and the redox properties of three systems of nanometric of silver-based catalysts were summarized. In this work, these catalysts were investigated for the simultaneous removal of particulate matter (diesel soot, and NOX was compared with that of a model of Pt-Ba/Al2O3 catalyst. The Silver-Barium based catalytic materials of Ag (5 wt%-Ba(10 wt%/MO (MO=Al2O3, CeO2, ZrO2, and Ag (5 wt%-Sr (10 wt%/CeO2 catalysts have been prepared by wetness impregnation method and characterized by BET, XRD, HRTEM, XPS and TPR (temperature-programmed reduction experiments. The behavior of the catalyst in the soot combustion (under tight conditions and NOX elimination has been separately analyzed by means of temperature programmed oxidation and isothermal concentration step change experiments, respectively. The results showed that all the catalysts were active in soot combustion with an indicative decrease of oxidation onset temperature compared to uncatalyzed soot oxidation. The removal of NOX in the presence and in the absence of soot was investigated under cycling conditions, i.e. alternating lean-rich phases according to the LNT approach. It has been found that the Ag-based samples were able to simultaneously remove soot and NOX. In particular, studying the behavior of the prepared catalysts, the Ba-containing systems exhibited higher NOX storage capacity than Sr-catalyst; also, the nitrogen selectivity increased even if resulted lower than the traditional LNT Pt-based catalyst. An adverse effect of soot on the NOX storage activity has been also observed. Copyright © 2017 BCREC GROUP. All rights reserved Received: 18th August 2016; Revised: 19th October 2016; Accepted: 19th October 2016 How to Cite: Dhal, G.C., Dey, S., Prasad, R., Mohan, D. (2017. Simultaneous Elimination of Soot and NOX through Silver-Barium Based Catalytic Materials. Bulletin of

  11. ASCR{trademark}: lower NOx removal costs without sacrificing performance

    Energy Technology Data Exchange (ETDEWEB)

    Bible, S.; Rummenhohl, V.; Siebeking, M.; Thomas, R.; Triece, C. [Fuel Tech (United States)

    2011-05-15

    With recent regulatory initiatives, the new Industrial Emissions Directive in Europe, and new rules being proposed by EPA in the USA, the question for power plants is now whether they will be required to reduce NOx emissions in the future to stay in operation, but when. What is needed is a low-capital-cost but high-performance NOx removal technology. 7 figs.

  12. Hybrid selective noncatalytic reduction (SNCR)/selective catalytic reduction (SCR) for NOx removal using low-temperature SCR with Mn-V2O5/TiO2 catalyst.

    Science.gov (United States)

    Choi, Sung-Woo; Choi, Sang-Ki; Bae, Hun-Kyun

    2015-04-01

    A hybrid selective noncatalytic reduction/selective catalytic reduction (SNCR/SCR) system that uses two types of technology, low-temperature SCR process and SNCR process, was designed to develop nitrogen oxide (NOx) reduction technology. SCR was conducted with space velocity (SV)=2400 hr(-1) and hybrid SNCR/SCR with SV=6000 hr(-1), since the study focused on reducing the amount of catalyst and both achieved 98% NOx reduction efficiency. Characteristics of NOx reduction by NH3 were studied for low-temperature SCR system at 150 °C using Mn-V2O5/TiO2 catalyst. Mn-added V2O5/TiO2 catalyst was produced, and selective catalyst reduction of NOx by NH3 was experimented. NOx reduction rate according to added Mn content in Mn-V2O5/TiO2 catalyst was studied with varying conditions of reaction temperature, normalized stoichiometric ratio (NSR), SV, and O2 concentration. In the catalyst experiment according to V2O5 concentration, 1 wt.% V2O5 catalyst showed the highest NOx reduction rate: 98% reduction at temperature window of 200~250 °C. As a promoter of the V2O5 catalyst, 5 wt.% Mn was added, and the catalyst showed 47~90% higher efficiency even with low temperatures, 100~200 °C. Mn-V2O5/TiO2 catalyst, prepared by adding 5 wt.% Mn in V2O5/TiO2 catalyst, showed increments of catalyst activation at 150 °C as well as NOx reduction. Mn-V2O5/TiO2 catalyst showed 8% higher rate for NOx reduction compared with V2O5/TiO2 catalyst in 150 °C SCR. Thus, (5 wt.%)Mn-(1 wt.%)V2O5/TiO2 catalyst was applied in SCR of hybrid SNCR/SCR system of low temperature at 150 °C. Low-temperature SCR hybrid SNCR/SCR (150 °C) system and hybrid SNCR/SCR (350 °C) showed 91~95% total reduction rate with conditions of SV=2400~6000 hr(-1) SCR and 850~1050 °C SNCR, NSR=1.5~2.0, and 5% O2. Hybrid SNCR/SCR (150 °C) system proved to be more effective than the hybrid SNCR/SCR (350 °C) system at low temperature. NOx control is very important, since they are the part of greenhouse gases as well as the

  13. Neutron studies of nanostructured CuO-Al2O3 NOx removal catalysts

    International Nuclear Information System (INIS)

    Ozawa, Masakuni; Loong Chun-Keung

    1997-01-01

    Nanostructured powders of automotive catalytic system CuO0Al 2 O 3 , targeted for nitrogen oxides (NOx) removal under lean-burn engine conditions, were investigated using neutron diffraction and small-angle neutron scattering. The crystal phases, structural transformations and microstructure of 10 mol% Cu-Al 2 O 3 powders are characterized according to the heat-treatment conditions. These properties are correlated with the pore structure and NOx removal efficiency determined by nitrogen adsorption isotherm, electron spin resonance, and temperature programmed reaction measurements. The γ-(Cu, Al) 2 O 3 phase and the mass-fractal-like aggregate of particles (size ∼ 26 nm) at annealing temperatures below 900 degrees C were found to be crucial to the high NOx removal performance. The transformation to bulk crystalline phases of α-Al 2 O 3 + CuAl 2 O 4 spinel above ∼1050 degrees C corresponds to a drastic drop of Nox removal efficiency. The usefulness of neutron-scattering techniques as well as their complementarity with other traditional methods of catalytic research are discussed

  14. Multi-Stage Selective Catalytic Reduction of NOx in Lean-Burn Engine Exhaust

    National Research Council Canada - National Science Library

    Penetrante, B

    1997-01-01

    .... A plasma can also be used to oxidize NO to NO2. This paper compares the multi-stage catalytic scheme with the plasma-assisted catalytic scheme for reduction of NOx in lean-burn engine exhausts. The advantages of plasma oxidation over catalytic oxidation are presented.

  15. Chemically enhanced biological NOx removal from flue gases : nitric oxide and ferric EDTA reduction in BioDeNox reactors

    NARCIS (Netherlands)

    Maas, van der P.M.F.

    2005-01-01

    The emission of nitrogen oxides (NOx) to the atmosphere is a major environmental problem. To abate NOx emissions from industrial flue gases, to date, mainly chemical processes like selective catalytic reduction (SCR) are applied. All these processes require high temperatures (>300 °C) and

  16. Ambient Temperature Hydrocarbon Selective Catalytic Reduction of NOx Using Atmospheric Pressure Nonthermal Plasma Activation of a Ag/Al2O3 Catalyst

    OpenAIRE

    Stere, Cristina E.; Adress, Wameedh; Burch, Robbie; Chansai, Sarayute; Goguet, Alexandre; Graham, William G.; De Rosa, Fabio; Palma, Vincenzo; Hardacre, Christopher

    2014-01-01

    Atmospheric pressure nonthermal-plasma-activated catalysis for the removal of NOx using hydrocarbon selective catalytic reduction has been studied utilizing toluene and n-octane as the hydrocarbon reductant. When the plasma was combined with a Ag/Al2O3 catalyst, a strong enhancement in activity was observed when compared with conventional thermal activation with high conversions of both. NOx and hydrocarbons obtained at temperature at temperature ≤250 °C, where the silver catalyst is normally...

  17. Congressionally Directed Project for Passive NOx Removal Catalysts Research

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, William [Univ. of Notre Dame, IN (United States)

    2014-12-29

    The Recipient proposes to produce new scientific and technical knowledge and tools to enable the discovery and deployment of highly effective materials for the selective catalytic reduction (SCR) of nitrogen oxides (NOx) from lean combustion exhaust. A second goal is to demonstrate a closely coupled experimental and computational approach to heterogeneous catalysis research. These goals will be met through the completion of four primary technical objectives: First, an in-depth kinetic analysis will be performed on two prominent classes of NOx SCR catalysts, Fe- and Cu-exchanged beta and ZSM-5 zeolites, over a wide range of catalyst formulation and under identical, high conversion conditions as a function of gas phase composition. Second, the nanoscale structure and adsorption chemistry of these high temperature (HT) and low temperature (LT) catalysts will be determined using in situ and operando spectroscopy under the same reaction conditions. Third, first-principles molecular simulations will be used to model the metal-zeolite active sites, their adsorption chemistry, and key steps in catalytic function. Fourth, this information will be integrated into chemically detailed mechanistic and kinetic descriptions and models of the operation of these well- defined NOx SCR catalysts under practically relevant reaction conditions. The new knowledge and models that derive from this work will be published in the scientific literature.

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

    Science.gov (United States)

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

    2015-09-01

    Diesel vehicles are responsible for most of the traffic-related nitrogen oxide (NOx) emissions, including nitric oxide (NO) and nitrogen dioxide (NO2). The use of after-treatment devices increases the risk of high NO2/NOx emissions from diesel engines. In order to investigate the factors influencing NO2/NOx emissions, an emission experiment was carried out on a high pressure common-rail, turbocharged diesel engine with a catalytic diesel particulate filter (CDPF). NO2 was measured by a non-dispersive ultraviolet analyzer with raw exhaust sampling. The experimental results show that the NO2/NOx ratios downstream of the CDPF range around 20%-83%, which are significantly higher than those upstream of the CDPF. The exhaust temperature is a decisive factor influencing the NO2/NOx emissions. The maximum NO2/NOx emission appears at the exhaust temperature of 350°C. The space velocity, engine-out PM/NOx ratio (mass based) and CO conversion ratio are secondary factors. At a constant exhaust temperature, the NO2/NOx emissions decreased with increasing space velocity and engine-out PM/NOx ratio. When the CO conversion ratios range from 80% to 90%, the NO2/NOx emissions remain at a high level. Copyright © 2015. Published by Elsevier B.V.

  19. OPTIMIZATION OF CHAR FOR NOx REMOVAL

    Energy Technology Data Exchange (ETDEWEB)

    J. Phillips; L.R. Radovic; B. Xia; J.A. Menendez

    1999-09-01

    Work performed for this study demonstrates that the temperature of treatment and the identity of the treatment gas both strongly impact the surface chemistry of activated carbon. Two commercial activated carbons were treated in either N{sub 2} or H{sub 2} at different temperatures up to 2600 C. Several techniques--including microcalorimetry, point of zero charge measurements, thermal desorption--were used to provide insight into important aspects of the chemical surface properties. The results show that activated carbons treated at high temperatures (ca. 950 C) in hydrogen will not react with oxygen and water at ambient temperatures; moreover, surfaces created in this fashion have stable properties in ambient conditions for many months. In contrast, the same carbons treated in an inert gas (e.g., N{sub 2}) will react strongly with oxygen and water at ambient temperatures. In the presence of platinum (or any other noble metal), stable basic carbons, which will not adsorb oxygen in ambient laboratory conditions, can be created via a relatively low-temperature process. Treatment at higher temperatures (>1500 C) produced increasingly stable surfaces in either N{sub 2} or H{sub 2}. A structural model is proposed. To wit: Treatment at high temperatures in any gas will lead to the desorption of oxygen surface functionalities in the form of CO and/or CO{sub 2}. Absent any atom rearrangement, the desorption of these species will leave highly unsaturated carbon atoms (''dangling carbons'') on the surface, which can easily adsorb O{sub 2} and H{sub 2}O. In an inert gas these ''dangling carbons'' will remain, but hydrogen treatments will remove these species and leave the surface with less energetic sites, which can only adsorb O{sub 2} at elevated temperatures. Specifically, hydrogen reacts with any highly unsaturated carbons in the surface to form methane. At temperatures greater than 1500 C (e.g., 1800 C, 2600 C), structural annealing

  20. NOx Selective Catalytic Reduction (SCR) on Self-Supported V-W-doped TiO2 Nanofibers

    DEFF Research Database (Denmark)

    Marani, Debora; Silva, Rafael Hubert; Dankeaw, Apiwat

    2017-01-01

    Electrospun V–W–TiO2 catalysts, resulting in a solid solution of V and W in the anatase phase, are prepared as nonwoven nanofibers for NOx selective catalytic reduction (SCR). Preliminary catalytic characterization indicates their superior NOx conversion efficiency to the-state-of-the-art material...

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

    Energy Technology Data Exchange (ETDEWEB)

    Unknown

    2001-12-01

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

  2. NOx Binding and Dissociation: Enhanced Ferroelectric Surface Chemistry by Catalytic Monolayers

    Science.gov (United States)

    Kakekhani, Arvin; Ismail-Beigi, Sohrab

    2013-03-01

    NOx molecules are regulated air pollutants produced during automotive combustion. As part of an effort to design viable catalysts for NOx decomposition operating at higher temperatures that would allow for improved fuel efficiency, we examine NOx chemistry on ferroelectric perovskite surfaces. Changing the direction of ferroelectric polarization can modify surface electronic properties and may lead to switchable surface chemistry. Here, we describe our recent work on potentially enhanced surface chemistry using catalytic RuO2 monolayers on perovskite ferroelectric substrates. In addition to thermodynamic stabilization of the RuO2 layer, we present results on the polarization-dependent binding of NO, O2, N2, and atomic O and N. We present results showing that one key problem with current catalysts, involving the difficulty of releasing dissociation products (especially oxygen), can be ameliorated by this method. Primary support from Toyota Motor Engineering and Manufacturing, North America, Inc.

  3. Catalytic Reduction of NO and NOx Content in Tobacco Smoke

    Directory of Open Access Journals (Sweden)

    Cvetkovic N

    2014-12-01

    Full Text Available In order to reduce the nitric oxide (NO and nitrogen oxides (NO content in mainstream tobacco smoke, a new class of catalyst based on Cu-ZSM-5 zeolite has been synthesized. The effectiveness of the new catalyst (degree of reduction and specific catalytic ability was tested both by adding Cu-ZSM-5 zeolite directly to the tobacco blend and by addition to the filter. We have determined that adding the catalyst to the tobacco blend does not cause any changes in the physical, chemical or organoleptic properties of the cigarette blend. But, the addition reduces the yield of nitrogen oxides while having no influence on nicotine and “tar” content in the tobacco smoke of the modified blend. The catalyst addition increases the static burning rate (SBR. The changes in the quantity of NO and NOmay be explained by changes in burning conditions due to the increase of Oobtained from catalytic degradation of NO and NO, and adsorptive and diffusive properties of the catalyst. The changes in mainstream smoke analytes are also given on a puff-by-puff basis.

  4. Selective catalytic reduction of NOx by hydrocarbons over Fe/ZSM5 prepared by sublimation of FeCl3

    NARCIS (Netherlands)

    Battiston, A.A.

    2003-01-01

    Selective Catalytic Reduction of NOx by Hydrocarbons over Fe/ZSM5 Prepared by Sublimation of FeCl3. Characterization and Catalysis Nitrogen oxides (NOx) are unwanted by-products of combustion. They are generated primarily from motor vehicles and stationary sources, like power stations and

  5. Selective catalytic reduction of NOx over pyrolyzed sludge char

    International Nuclear Information System (INIS)

    Ko, Jeong Huy; Heo, Hyeon Su; Park, Hye Jin; Bae, Yoon Ju; Kim, Jung Hwan; Cho, Hye Jung; Park, Young Kwon

    2010-01-01

    Full text: In this study, applicability of the activated pyrolyzed sludge char as a De-NO x catalyst was investigated. Sludge chars were generated by the pyrolysis condition, such as temperature, heating rate and reaction time. As pyrolysis temperature increased from 300 to 600 degree Celsius, the specific surface area and porosity of sludge chars were increased but were reduced at 700 degree Celsius, and thereafter were increased at 800 degree Celsius again. However, the pyrolysis heating rate and reaction time had an no large effect on the specific area and porosity of sludge chars. Considering these results, the pyrolysis temperature was the most parameter to affecting the specific area and porosity of sludge chars. In order to enhance the physical characteristics of sludge chars, they were activated by the physical and chemical activation methods with steam and KOH, respectively, and the effects of the activation temperature, moisture concentration and KOH/ char ratio on the physical characteristics of sludge chars were also studied. Chemically activated sludge chars showed the higher NO x removal efficiency than physically ones. Especially, the sludge char activated under the condition of a KOH/ Char ratio 2.0 and temperature 600 degree Celsius exhibited the highest NO x removal efficiency of 84.2% at 250 degree Celsius, which was even higher than 35.6% over a commercial activated carbon. (author)

  6. Removal of NOx by pulsed, intense relativistic electron beam in distant gas chamber

    International Nuclear Information System (INIS)

    Imada, Go; Sakurai, Tomoki; Jiang Weihua; Yatsui, Kiyoshi

    2002-01-01

    Removal of NOx has been studied using a pulsed, intense relativistic electron beam (IREB). The dependence of NOx concentration and the removal efficiency of NOx on the number of IREB shot have been investigated within a distant gas chamber spatially isolated from the electron beam source. The distant gas chamber is filled up with a dry-air-balanced NO gas mixture with the pressure of 270 kPa, and is irradiated by the IREB (2 MeV, 30 A, 35 ns) passing through a 1.6-m-long atmosphere. With the initial NO concentration of 88 ppm, ∼ 70 % of NOx is successfully removed by firing 10 shots of IREB. The NOx removal efficiency has been found to be 50-155 g/kWh

  7. Photocatalytic removal of nitrogen oxides from ambient air using solar energy; Taiyo energy wo riyoshita taikichu no NOx no hikari shokubai jokyo

    Energy Technology Data Exchange (ETDEWEB)

    Fukaya, M.; Taoda, H.; Watanabe, E.; Nonami, T.; Iseda, K.; Kato, K. [National Industrial Research Institute of Nagoya, Nagoya (Japan); Kunieda, S. [NGK Insulators, Ltd., Nagoya (Japan); Kato, S.

    1997-11-25

    Experiment was made on removal of NOx from ambient air using ceramic blocks coated with a newly developed easy-to- handle TiO2 film photocatalyst. After TiO2 sol was prepared by hydrolyzing titanium tetraisopropoxide, the photocatalytic blocks were prepared through drying and sintering after immersing the blocks in TiO2 sol. The effect of the number of coating on catalytic performance was studied using the single-coated and triple-coated blocks. Artificial solar light of 1mW/cm{sup 2} was used as light source for flowing reaction experiment of air (containing NOx) in a laboratory. NOx concentration rapidly decreased with irradiation, and 94% and 98% of NOx were removed by the single- and triple-coated blocks, respectively. NOx was completely oxidized to HNO3 through NO2 by triple-coated blocks. The demonstration test of removal of NOx from ambient air in Okazaki city showed a removal rate of nearly 90% in noonday and 40% or more in average, while not 0% but 5-20% even in the nighttime. The latter is probably derived from adsorption by the porous photocatalytic blocks. 2 figs., 4 tabs.

  8. 75 FR 6336 - Approval and Promulgation of Air Quality Implementation Plans; West Virginia; Removal of NOX

    Science.gov (United States)

    2010-02-09

    ... ENVIRONMENTAL PROTECTION AGENCY 40 CFR Part 52 [EPA-R03-OAR-2009-0706; FRL-9111-6] Approval and Promulgation of Air Quality Implementation Plans; West Virginia; Removal of NOX SIP Call Rules AGENCY... oxides (NOx) SIP Call rules. In the Final Rules section of this Federal Register, EPA is approving the...

  9. Hollow fiber contractors for simultaneous SOx/NOx removal

    International Nuclear Information System (INIS)

    Bhown, A.S.; Pakala, N.R.; Riggs, T.

    1995-01-01

    Control of SO x and NO x emissions from coal-fired utility and industrial boilers is a topic of growing national and international importance. Whereas a host of commercial and semicommercial processes exist, increasingly stringent emission standards mandate that processes be low cost, highly efficient, and, ideally, produce marketable byproducts. Although a wide range of site-specific economic factors dictate the best choice of SO x and NO x control, removal of SO 2 by wet limestone scrubbing and removal of NO x by selective catalytic reduction (SCR) are regarded as the best commercialized technologies for this application. A typical wet limestone plant requires approximately $100 to $120 of capital investment per kilowatt of electric power generating capacity and has power and miscellaneous operating costs in the range of 5 to 6 mils per kilowatt hour (kWh). The SCR process requires approximately $70 to $100 of capital investment per kilowatt of electric power generating capacity. Its operating costs, including ammonia consumption, is in the range of 1.8 to 2.2 mils per kWh. These costs can add approximately 20% to the final cost of generated electricity, a significant burden on rate payers

  10. Possible Catalytic Effects of Ice Particles on the Production of NOx by Lightning Discharges

    Science.gov (United States)

    2010-01-01

    One mechanism by which NO(x) is produced in the atmosphere is heating in lightning discharge channels. Since most viable proposed electrification mechanisms involve ice crystals, it is reasonable to assume that lightning discharge channels frequently pass through fields of ice particles of various kinds. We address the question of whether ice crystals may serve as catalysts for the production of NO(x) by lightning discharges. If so, and if the effect is large, it would need to be taken into account in estimates of global NO(x) production by lightning. In this study, we make a series of plausible assumptions about the temperature and concentration of reactant species in the environment of discharges and we postulate a mechanism by which ice crystals are able to adsorb nitrogen atoms. We then compare production rates between uncatalyzed and catalytic reactions at 2000 K, 3000 K, and 4000 K. Catalyzed NO production rates are greater at 2000 K, whereas uncatalyzed production occurs most rapidly at 4000 K. 2010

  11. Electrochemical Removal of NOx on Ceria-Based Catalyst-Electrodes

    Directory of Open Access Journals (Sweden)

    Xi Wang

    2017-02-01

    Full Text Available This study reports the electrochemical properties for NOx reduction of a ceria-based mixed ionic electronic conducting porous electrode promoted by Pt nanoparticles, as efficient catalyst for NO oxidation, and BaO, as sorbent to store NOx. This catalytic layer was deposited by screen-printing on a dense membrane of gadolinia-doped ceria, an O2− ionic conductor. The targeted Ba and Pt loadings were 150 and 5 μg/cm2, respectively. The NOx selective electrochemical reduction was performed between 400 °C and 500 °C with and without oxygen in the feed. Variations of the open-circuit voltage with time were found to be a good sensor of the NOx storage process on the ceria-based catalyst-electrode. However, no N2 production was observed in the presence of O2 phase in spite of nitrates formation.

  12. Role of iron oxide catalysts in selective catalytic reduction of NOx and soot from vehicular emission

    International Nuclear Information System (INIS)

    Anjuman, S.; Tahira, S.; Hizbullah, K.; Hizbullah, K.

    2011-01-01

    This study deals with Iron containing catalysts i.e Iron oxide Fe/sub 2/O/sub 3/) Iron potassium oxide Fe/sub 1.9/K/sub 0.1/O/sub 3/, copper iron oxide Cu/sub 0.9/K/sub 0.1/, Fe/sub 2/O/sub 3/, nickel iron oxide Ni Fe/sub 2/O/sub 4/, and Nickel potassium iron oxide Ni/sub 0.95/K/sub 0.05/ Fe/sub 2/O/sub 4/ catalyst were synthesized by using PVA technique. By X-ray Diffraction technique these catalysts were characterized to ensure the formation of crystalline structure. Energy Dispersive X-rays analysis (EDX) was used for the confirmation of presence of different metals and Scanning Electron Microscopy (SEM) for Surface Morphology. Then the catalytic investigations of the prepared catalyst were carried out for their activity measurement toward simultaneous conversion of NOx and Soot from an engine exhaust. Some Iron containing oxide catalysts were partially modified by alkali metal potassium and were used for NOx -Soot reaction in a model exhaust gas. Fe/sub 1.9 K /sub 0.1/O/sub 3/ show high catalytic performance for N/sub 2/ formation in the prepared catalyst. Further studies have shown that Fe/sub 1.9/ K/sub 0.1/ O/sub 3/ was deactivated in a substantial way after about 20 Temperature. Temperature Programmed Reaction (TPR) experiments due to agglomeration of the promoter potassium. Experiments carried out over the aged Fe/sub 1.9/K/sub 0.1/O/sub 3/ catalyst have shown that NOx-soot reaction was suppressed at higher oxygen concentration, since O/sub 2/-soot conversion was kindly favored. More over nitrite species formed at the catalyst surface might play an important role in NOx-soot conversion. (author)

  13. Enhancement of removal of SO2 and NOx by powdery materials in radiation treatment of exhaust gases

    International Nuclear Information System (INIS)

    Tokunaga, Okihiro; Namba, Hideki; Suzuki, Nobutake

    1985-01-01

    We studied the effect of powdery silica on radiation removal of SO 2 and NOx from mixtures of SO 2 , NOx, water vapour, oxygen and nitrogen under irradiation by electron beams of 1.5 MeV at 120 0 C. The SO 2 and NOx concentrations decreased when powdery silica was fed without irradiation. Decrements of SO 2 and NOx concentrations were markedly enhanced when powdery silica was fed together with the irradiation. The enhancement of SO 2 - and NOx-removal is attributed to the adsorption of SO 2 and NO on the water-covered surface of powdery silica, and the effective removal of NO 2 due to the reaction with water adsorbed on the surface of powdery silica. The results obtained show that the addition of powdery silica under irradiation is an effective method of enhancing the removal of SO 2 and NOx. (author)

  14. CO2 , NOx and SOx removal from flue gas via microalgae cultivation: a critical review.

    Science.gov (United States)

    Yen, Hong-Wei; Ho, Shih-Hsin; Chen, Chun-Yen; Chang, Jo-Shu

    2015-06-01

    Flue gas refers to the gas emitting from the combustion processes, and it contains CO2 , NOx , SOx and other potentially hazardous compounds. Due to the increasing concerns of CO2 emissions and environmental pollution, the cleaning process of flue gas has attracted much attention. Using microalgae to clean up flue gas via photosynthesis is considered a promising CO2 mitigation process for flue gas. However, the impurities in the flue gas may inhibit microalgal growth, leading to a lower microalgae-based CO2 fixation rate. The inhibition effects of SOx that contribute to the low pH could be alleviated by maintaining a stable pH level, while NOx can be utilized as a nitrogen source to promote microalgae growth when it dissolves and is oxidized in the culture medium. The yielded microalgal biomass from fixing flue gas CO2 and utilizing NOx and SOx as nutrients would become suitable feedstock to produce biofuels and bio-based chemicals. In addition to the removal of SOx , NOx and CO2 , using microalgae to remove heavy metals from flue gas is also quite attractive. In conclusion, the use of microalgae for simultaneous removal of CO2 , SOx and NOx from flue gas is an environmentally benign process and represents an ideal platform for CO2 reutilization. Copyright © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Graphene and g-C3N4 based photocatalysts for NOx removal: A review

    Science.gov (United States)

    Nikokavoura, Aspasia; Trapalis, Christos

    2018-02-01

    NOx liberated into atmosphere from automobile exhausts and fossil fuel combustion, comprise the major air pollutants. They are responsible for serious environmental problems such as acid rain, ozone accumulation, haze and photochemical smog. Besides they contribute to the deterioration of human health by causing decrease of the lung function and respiratory problems. The application of photocatalytic methods in order to mitigate the presence of NOx in the atmosphere is preferable as they are environmentally friendly, mild and low cost. Therefore, in this review, the photocatalytic activity of g-C3N4 and graphene based composites towards NOx removal was discussed. NOx oxidation to non volatile nitrates on the surface of graphene and g-C3N4 based photocatalysts has attracted much interest during the last years due to their structures with unique features such as large specific surface area, thermal and chemical stability and enhanced visible light utilization. The formation of 2D-2D intimate heterojunctions between graphene or g-C3N4 and other components ensures the enhanced charge transfer, lifetime of electron/hole pairs and thus photocatalytic activity. The increased visible light harvesting also contributes to their usefulness as effective photocatalytic materials. In the present work, the advantages of these novel photocatalysts and the differences/similarities between them were exhaustively highlighted. The role of graphene as catalyst promoter, electron reservoir, support and photosensitizer in its photocatalytic composites was emphasized. The effect of g-C3N4 doping and copolymerization with metals/semiconductors on its photocatalytic activity towards NOx oxidation was thoroughly discussed. Besides, the preparation methods, photocatalytic efficiencies, type of irradiation, utilization of appropriate cocatalysts, and reaction mechanisms during the photocatalytic NOx removal by graphene and g-C3N4 composies, were summarized. It was demonstrated that in the vast

  16. Low-temperature deposition of anatase on nanofiber materials for photocatalytic NOX removal

    Czech Academy of Sciences Publication Activity Database

    Szatmáry, Lórant; Šubrt, Jan; Kalousek, Vít; Mosinger, Jiří; Lang, Kamil

    2014-01-01

    Roč. 230, jul (2014), s. 74-78 ISSN 0920-5861 R&D Projects: GA ČR GA13-12496S Institutional support: RVO:61388980 ; RVO:61388955 Keywords : Anatase * Nanofiber * Coating * TiO2 * Photocatalysis * NOx removal Subject RIV: CA - Inorganic Chemistry Impact factor: 3.893, year: 2014

  17. Biological NOx removal by denitrification process in a jet-loop bioreactor: system performance and model development.

    Science.gov (United States)

    Durmazpinar, Serdar; Ilhan, Nalan; Demir, Gonca; Insel, Güçlü; Dizge, Nadir; Ergenekon, Pinar; Erhan, Elif; Keskinler, Bülent

    2014-01-01

    Nitrogen monoxide (NO) and nitrogen dioxide referred as NOx are one of the most important air pollutants in the atmosphere. Biological NOx removal technologies have been developing to reach a cost-effective control method for upcoming stringent NOx emission standards. The BioDeNOx system was seen as a promising biological NOx control technology which is composed of two reactors, one for absorbing of NO in an aqueous Fe(II)EDTA2- solution and the other for subsequent reduction to N2 gas in a biological reactor by the denitrification process. In this study, instead of two discrete reactors, only one jet-loop bioreactor (JLBR) was utilized as both absorption and denitrification unit and no chelate-forming chemicals were added. In other words, the advantage of better mass transfer conditions of jet bioreactor was used instead of Fe(II)EDTA2-. The process was named as Jet-BioDeNOx. The JLBR was operated for the removal of NOx from air streams containing 500-3000 ppm NOx and the results showed that the removal efficiency was between 81% and 94%. The air to liquid flow ratio (Q(G)/Q(RAS)) varied in the range of 0.07-0.12. Mathematical modelling of the system demonstrated that the removal efficiency strongly depends on this ratio. The high mass transfer conditions prevailed in the reactor provided a competitive advantage on removing NO gas without any requirement of chelating chemicals.

  18. NOx removal enhancement by a Jerks - and - Jumps type electrode in a dielectric barrier discharge

    International Nuclear Information System (INIS)

    Mercado-Cabrera, A; Villar, E L del; Valencia-Alvarado, R; Lopez-Callejas, R; Barocio, S R; Pena-Eguiluz, R; Munozoz-Castro, A; Jaramillo-Sierra, B; Piedad-Beneitez, A de la

    2008-01-01

    In this study, the electrode surface of a NOx removal treatment reactor has been modified in order to reduce its electric potential level and, at the same time, to increase its removal capacity by generating a cold plasma using a non-homogenous electric field on the electrode surface. This electric field has been achieved by means of a jerks and jumps-like electrode profile. The other electrode conserves the original flat form. Then, experiments on the removal of NOx were carried out in this 22.4 cm 3 reactor. Concentrations of 30-80 μmol/mol of NOx in nitrogen were used with 1 SLPM flows. The exhaust gases were analysed as well as characterised by gas chromatography and mass spectrometry. Additional experiments were also carried out in a second reactor of the same reaction volume but where two conventional flat and parallel electrodes were used, in order to compare the results. The NO removal efficiency in the two flat electrode case approached 87% while ∼98% in the jerks and jumps reactor

  19. Sulfur and Water Resistance of Mn-Based Catalysts for Low-Temperature Selective Catalytic Reduction of NOx: A Review

    Directory of Open Access Journals (Sweden)

    Chen Gao

    2018-01-01

    Full Text Available Selective catalytic reduction (SCR with NH3 is the most efficient and economic flue gas denitrification technology developed to date. Due to its high low-temperature catalytic activity, Mn-based catalysts present a great prospect for application in SCR de-NOx at low temperatures. However, overcoming the poor resistance of Mn-based catalysts to H2O and SO2 poison is still a challenge. This paper reviews the recent progress on the H2O and SO2 resistance of Mn-based catalysts for the low-temperature SCR of NOx. Firstly, the poison mechanisms of H2O and SO2 are introduced in detail, respectively. Secondly, Mn-based catalysts are divided into three categories—single MnOx catalysts, Mn-based multi-metal oxide catalysts, and Mn-based supported catalysts—to review the research progress of Mn-based catalysts for H2O and SO2 resistance. Thirdly, several strategies to reduce the poisonous effects of H2O and SO2, such as metal modification, proper support, the combination of metal modification and support, the rational design of structure and morphology, are summarized. Finally, perspectives and future directions of Mn-based catalysts for the low-temperature SCR of NOx are proposed.

  20. The acclimation of Chlorella to high-level nitrite for potential application in biological NOx removal from industrial flue gases

    Czech Academy of Sciences Publication Activity Database

    Li, T.; Xu, G.; Rong, J.; Chen, H.; He, Ch.; Giordano, Mario; Wang, Q.

    2016-01-01

    Roč. 195, May (2016), s. 73-79 ISSN 0176-1617 Institutional support: RVO:61388971 Keywords : Acclimation * Biological NOx removal * Chlorella Subject RIV: EF - Botanics Impact factor: 3.121, year: 2016

  1. Near-Zero Emissions Oxy-Combustion Flue Gas Purification Task 3: SOx/NOx/Hg Removal for Low Sulfur Coal

    Energy Technology Data Exchange (ETDEWEB)

    Zanfir, Monica; Solunke, Rahul; Shah, Minish

    2012-06-01

    The goal of this project was to develop a near-zero emissions flue gas purification technology for existing PC (pulverized coal) power plants that are retrofitted with oxycombustion technology. The objective of Task 3 of this project was to evaluate an alternative method of SOx, NOx and Hg removal from flue gas produced by burning low sulfur coal in oxy-combustion power plants. The goal of the program was to conduct an experimental investigation and to develop a novel process for simultaneously removal of SOx and NOx from power plants that would operate on low sulfur coal without the need for wet-FGD & SCRs. A novel purification process operating at high pressures and ambient temperatures was developed. Activated carbon's catalytic and adsorbent capabilities are used to oxidize the sulfur and nitrous oxides to SO{sub 3} and NO{sub 2} species, which are adsorbed on the activated carbon and removed from the gas phase. Activated carbon is regenerated by water wash followed by drying. The development effort commenced with the screening of commercially available activated carbon materials for their capability to remove SO{sub 2}. A bench-unit operating in batch mode was constructed to conduct an experimental investigation of simultaneous SOx and NOx removal from a simulated oxyfuel flue gas mixture. Optimal operating conditions and the capacity of the activated carbon to remove the contaminants were identified. The process was able to achieve simultaneous SOx and NOx removal in a single step. The removal efficiencies were >99.9% for SOx and >98% for NOx. In the longevity tests performed on a batch unit, the retention capacity could be maintained at high level over 20 cycles. This process was able to effectively remove up to 4000 ppm SOx from the simulated feeds corresponding to oxyfuel flue gas from high sulfur coal plants. A dual bed continuous unit with five times the capacity of the batch unit was constructed to test continuous operation and longevity. Full

  2. Wintertime Overnight NOx Removal in a Southeastern United States Coal-fired Power Plant Plume: A Model for Understanding Winter NOx Processing and its Implications

    Science.gov (United States)

    Fibiger, Dorothy L.; McDuffie, Erin E.; Dubé, William P.; Aikin, Kenneth C.; Lopez-Hilfiker, Felipe D.; Lee, Ben H.; Green, Jaime R.; Fiddler, Marc N.; Holloway, John S.; Ebben, Carlena; Sparks, Tamara L.; Wooldridge, Paul; Weinheimer, Andrew J.; Montzka, Denise D.; Apel, Eric C.; Hornbrook, Rebecca S.; Hills, Alan J.; Blake, Nicola J.; DiGangi, Josh P.; Wolfe, Glenn M.; Bililign, Solomon; Cohen, Ronald C.; Thornton, Joel A.; Brown, Steven S.

    2018-01-01

    Nitric oxide (NO) is emitted in large quantities from coal-burning power plants. During the day, the plumes from these sources are efficiently mixed into the boundary layer, while at night, they may remain concentrated due to limited vertical mixing during which they undergo horizontal fanning. At night, the degree to which NO is converted to HNO3 and therefore unable to participate in next-day ozone (O3) formation depends on the mixing rate of the plume, the composition of power plant emissions, and the composition of the background atmosphere. In this study, we use observed plume intercepts from the Wintertime INvestigation of Transport, Emissions and Reactivity campaign to test sensitivity of overnight NOx removal to the N2O5 loss rate constant, plume mixing rate, background O3, and background levels of volatile organic compounds using a 2-D box model of power plant plume transport and chemistry. The factor that exerted the greatest control over NOx removal was the loss rate constant of N2O5. At the lowest observed N2O5 loss rate constant, no other combination of conditions converts more than 10% of the initial NOx to HNO3. The other factors did not influence NOx removal to the same degree.

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

    Energy Technology Data Exchange (ETDEWEB)

    (1)Kass, M; Thomas, J; Lewis, S; Storey, J; Domingo, N; Graves, R (2) Panov, A

    2003-08-24

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

  4. State Estimation in the Automotive SCR DeNOx Process

    DEFF Research Database (Denmark)

    Zhou, Guofeng; Jørgensen, John Bagterp; Duwig, Christophe

    2012-01-01

    Selective catalytic reduction (SCR) of nitrogen oxides (NOx) is a widely applied diesel engine exhaust gas after-treatment technology. For effective NOx removal in a transient operating automotive application, controlled dosing of urea can be used to meet the increasingly restrictive legislations...

  5. Characterization of LSM/CGO Symmetric Cells Modified by NOx Adsorbents for Electrochemical NOx Removal with Impedance Spectroscopy

    DEFF Research Database (Denmark)

    Shao, Jing; Kammer Hansen, Kent

    2013-01-01

    This study uses electrochemical impedance spectroscopy (EIS) to characterize an LSM/CGO symmetric cell modified by NOx adsorbents for the application of electrochemical NOx reduction. Three cells were prepared and tested: a blank cell, a cell impregnated with BaO, and a cell coated with a Ba......O-Pt-Al2O3 layer. The impedance analysis revealed that modification with the NOx adsorbents, either by impregnating the BaO into the electrode or by adding a BaO-Pt-Al2O3 layer on top of the electrode significantly enhanced the electrode activity. This activity enhancement was mainly due to the decrease...... in the resistance of the low-frequency processes, which were ascribed to adsorption, diffusion, and transfer of O2 species and NOx species at or near the triple phase boundary (TPB) region and the formation of the reaction intermediate NO2. The BaO impregnation improved the adsorption of NOx on the LSM...

  6. On board catalytic NOx control: mechanistic aspects of the regeneration of Lean NOx Traps with H2

    International Nuclear Information System (INIS)

    Forzatti, Pio; Lietti, Luca; Nova, Isabella

    2008-01-01

    Mechanistic aspects of the reduction with H 2 of NO x stored on Lean NO x Trap catalysts are critically reviewed. It was shown that, under nearly isothermal conditions nitrogen formation occurs via an in series two-step process involving the participation of ammonia as an intermediate. The first step of this process is ammonia formation through the reaction of H 2 with stored nitrates; ammonia then reacts with the nitrates left on the catalysts surface leading to the formation of nitrogen. Over the investigated Ba-containing catalysts, the first step (i.e. NH 3 formation) is much faster than the second one which, therefore, is rate determining in the formation of nitrogen. Both steps are catalyzed by Pt and, under nearly isothermal conditions, do not involve the occurrence of a thermal decomposition step of the stored nitrates. Due to the fast reaction of the adsorbed nitrates with H 2 to give ammonia and to the integral behaviour of the trap, an H 2 front develops in the trap which travels along the reactor axis. Ammonia formed upon reaction of nitrates with H 2 reacts downstream of the H 2 front with nitrates leading to N 2 formation, if the temperature is high enough. This explains both the observed change in the selectivity of the process with time upon regeneration of the trap (with selectivity changing from N 2 to NH 3 ), and the increase in the N 2 selectivity with temperature as well. The identification of the pathway for the reduction of stored NO x , where ammonia is suggested as the intermediate product in the formation of nitrogen, may favour the improvement of the combined NSR + SCR technology that has been proposed by several car manufacturers to make NO x removal by NSR more effective and to simultaneously limit the ammonia slip (GB)

  7. Research progress on catalytic denitrification technology in chemical industry

    Science.gov (United States)

    Jin, Yezhi

    2017-12-01

    In recent years, due to the rising emission of NOx annually, attention has been aroused widely by people on more and more severe environmental problems. This paper first discusses applying NOx removal and control technologies and relating chemical principles. Of many technologies, selective reduction reaction (SCR) is the most widely used. Catalysts, the concentration of NOx at the entrance of SCR catalytic reactor, reaction temperature, NH3/NOx mole ratio and NH3 slip rate analyzed later contributes to the removal efficiency of NOx. Finally, the processing and configuration of SCR de-NOx system are briefly introduced.

  8. Reduction of NOx Emission of a Diesel Engine with a Multiple Injection Pump by SCR Catalytic Converter

    Directory of Open Access Journals (Sweden)

    Vít Marek

    2016-01-01

    Full Text Available This paper deals with reduction of NOx-emission of a diesel engine with multiple injection pump by SCR catalytic converter. Main aim of the measurement was the detection of SCR catalyst converter efficiency. Tests were realized at the Research and Development workplace of Zetor Tractor a.s. Used engine was equipped with a multiple injection pump with electromagnetic regulator of a fuel charge. During the experiment selective catalytic reduction and diesel particulate filter were used as an after treatment of harmful pollutants reduction. Testing cycle of the eight-point test was chosen and Non-Road Steady Cycle (NRSC was maintained according to 97/68/EC directive. Results confirmed the dependencies between temperatures of SCR catalyst and exhaust gases and the volume of exhaust gases on efficiency of SCR catalyst. During the operation load of the engine, selective catalytic reduction reached efficiency over 90 %. Used after treatment system is suitable for reduction of harmful pollutants according to the Tier 4f norm.

  9. Recent increases in nitrogen oxide (NOx) emissions from coal-fired electric generating units equipped with selective catalytic reduction.

    Science.gov (United States)

    McNevin, Thomas F

    2016-01-01

    The most effective control technology available for the reduction of oxides of nitrogen (NOx) from coal-fired boilers is selective catalytic reduction (SCR). Installation of SCR on coal-fired electric generating units (EGUs) has grown substantially since the onset of the U.S. Environmental Protection Agency's (EPA) first cap and trade program for oxides of nitrogen in 1999, the Ozone Transport Commission (OTC) NOx Budget Program. Installations have increased from 6 units present in 1998 in the states that encompass the current Cross-State Air Pollution Rule (CSAPR) ozone season program to 250 in 2014. In recent years, however, the degree of usage of installed SCR technology has been dropping significantly at individual plants. Average seasonal NOx emission rates increased substantially during the Clean Air Interstate Rule (CAIR) program. These increases coincided with a collapse in the cost of CAIR allowances, which declined to less than the cost of the reagent required to operate installed SCR equipment, and was accompanied by a 77% decline in delivered natural gas prices from their peak in June of 2008 to April 2012, which in turn coincided with a 390% increase in shale gas production between 2008 and 2012. These years also witnessed a decline in national electric generation which, after peaking in 2007, declined through 2013 at an annualized rate of -0.3%. Scaling back the use of installed SCR on coal-fired plants has resulted in the release of over 290,000 tons of avoidable NOx during the past five ozone seasons in the states that participated in the CAIR program. To function as designed, a cap and trade program must maintain allowance costs that function as a disincentive for the release of the air pollutants that the program seeks to control. If the principle incentive for reducing NOx emissions is the avoidance of allowance costs, emissions may be expected to increase if costs fall below a critical value, in the absence of additional state or federal

  10. Numerical simulation of urea based selective non-catalytic reduction deNOx process for industrial applications

    International Nuclear Information System (INIS)

    Baleta, Jakov; Mikulčić, Hrvoje; Vujanović, Milan; Petranović, Zvonimir; Duić, Neven

    2016-01-01

    Highlights: • SNCR is a simple method for the NOx reduction from large industrial facilities. • Capabilities of the developed mathematical framework for SNCR simulation were shown. • Model was used on the geometry of experimental reactor and municipal incinerator. • Results indicate suitability of the developed model for real industrial cases. - Abstract: Industrial processes emit large amounts of diverse pollutants into the atmosphere, among which NOx takes a significant portion. Selective non-catalytic reduction (SNCR) is a relatively simple method for the NOx reduction in large industrial facilities such as power plants, cement plants and waste incinerator plants. It consists of injecting the urea-water solution in the hot flue gas stream and its reaction with the NOx. During this process flue gas enthalpy is used for the urea-water droplet heating and for the evaporation of water content. After water evaporates, thermolysis of urea occurs, during which ammonia, a known NO x reductant, and isocyanic acid are generated. In order to cope with the ever stringent environmental norms, equipment manufacturers need to develop energy efficient products that are at the same time benign to environment. This is becoming increasingly complicated and costly, and one way to reduce production costs together with the maintaining the same competitiveness level is to employ computational fluid dynamics (CFD) as a tool, in a process today commonly known under the term “virtual prototyping”. The aim of this paper is to show capabilities of the developed mathematical framework implemented in the commercial CFD code AVL FIRE®, to simulate physical processes of all relevant phenomena occurring during the SNCR process. First, mathematical models for description of SNCR process are presented and afterwards, models are used on the 3D geometry of an industrial reactor and a real industrial case to predict SNCR efficiency, temperature and velocity field. Influence of the main

  11. The acclimation of Chlorella to high-level nitrite for potential application in biological NOx removal from industrial flue gases.

    Science.gov (United States)

    Li, Tianpei; Xu, Gang; Rong, Junfeng; Chen, Hui; He, Chenliu; Giordano, Mario; Wang, Qiang

    2016-05-20

    Nitrogen oxides (NOx) are the components of fossil flue gas that give rise to the greatest environmental concerns. This study evaluated the ability of the green algae Chlorella to acclimate to high level of NOx and the potential utilization of Chlorella strains in biological NOx removal (DeNOx) from industrial flue gases. Fifteen Chlorella strains were subject to high-level of nitrite (HN, 176.5 mmolL(-1) nitrite) to simulate exposure to high NOx. These strains were subsequently divided into four groups with respect to their ability to tolerate nitrite (excellent, good, fair, and poor). One strain from each group was selected to evaluate their photosynthetic response to HN condition, and the nitrite adaptability of the four Chlorella strains were further identified by using chlorophyll fluorescence. The outcome of our experiments shows that, although high concentrations of nitrite overall negatively affect growth and photosynthesis of Chlorella strains, the degree of nitrite tolerance is a strain-specific feature. Some Chlorella strains have an appreciably higher ability to acclimate to high-level of nitrite. Acclimation is achieved through a three-step process of restrict, acclimate, and thriving. Notably, Chlorella sp. C2 was found to have a high tolerance and to rapidly acclimate to high concentrations of nitrite; it is therefore a promising candidate for microalgae-based biological NOx removal. Copyright © 2016 Elsevier GmbH. All rights reserved.

  12. Electrochemical Removal of NOx-Gasses by Use of LSM-Cathodes Impregnated with a NOx Storage Compound

    DEFF Research Database (Denmark)

    Traulsen, Marie Lund; Kammer Hansen, Kent

    2010-01-01

    Electrochemical decomposition of NO on La0.85Sr0.15MnO3-- Ce0.90Gd0.10O1.95electrodes with and without KNO3 impregnation is investigated. The KNO3 is added as this compound is expected to work as a NOx-storage compound. Measurements are made in the temperature range 300-400 degree C and in three...

  13. TiO2 functionalization for efficient NOx removal in photoactive cement

    Science.gov (United States)

    Karapati, S.; Giannakopoulou, T.; Todorova, N.; Boukos, N.; Antiohos, S.; Papageorgiou, D.; Chaniotakis, E.; Dimotikali, D.; Trapalis, C.

    2014-11-01

    Commercial titania nanoparticles (P25 Evonic-Degussa) were modified with organic compounds oleic acid (OA), oleylamine (OM) and equimolar concentrations of both modifiers (OAOM) through a biphase toluene/water emulsion processing in order to be endowed with hydrophobic properties. Specific molar ratio 3 between modifier and titania powder was used. The modified and the initial P25 photocatalysts were embedded in cement matrix in low percentage loading (2.5, 1, 0.5%). The grafting of the modifier to the titania nanoparticles was verified by thermal gravimetric analysis (TGA), differential thermal analysis (DTA), and Fourier transform infrared spectroscopy (FT-IR). Light absorption measurements revealed that the energy band gap of the photocatalysts was lowered after the modification. The average size (nm) and polydisperse index of the initial and modified P25 were determined via dynamic light scattering (DLS). The photocatalytic activity of the photocatalysts alone and the composite cement specimens was evaluated via ISO standard NOx oxidation procedure. The photocatalytic cements containing modified P25 exhibited 2-5 times better NOx removal than those with non-modified P25 even for the lowest photocatalyst loading. The results were attributed to the hydrophobic properties of the modified titania and its behavior during the incorporation in the cement matrix. This conclusion was confirmed by the SEM/EDX analysis which demonstrated a gradual increase of hydrophobic photocatalyst from the bottom to the surface of the cement specimens.

  14. Potential application of aerobic denitrifying bacterium Pseudomonas aeruginosa PCN-2 in nitrogen oxides (NOx) removal from flue gas.

    Science.gov (United States)

    Zheng, Maosheng; Li, Can; Liu, Shufeng; Gui, Mengyao; Ni, Jinren

    2016-11-15

    Conventional biological removal of nitrogen oxides (NOx) from flue gas has been severely restricted by the presence of oxygen. This paper presents an efficient alternative for NOx removal at varying oxygen levels using the newly isolated bacterial strain Pseudomonas aeruginosa PCN-2 which was capable of aerobic and anoxic denitrification. Interestingly, nitric oxide (NO), as the obligatory intermediate, was negligibly accumulated during nitrate and nitrite reduction. Moreover, normal nitrate reduction with decreasing NO accumulation was realized under O2 concentration ranging from 0 to 100%. Reverse transcription and real-time quantitative polymerase chain reaction (RT-qPCR) analysis revealed that high efficient NO removal was attributed to the coordinate regulation of gene expressions including napA (for periplasmic nitrate reductase), nirS (for cytochrome cd1 nitrite reductase) and cnorB (for NO reductase). Further batch experiments demonstrated the immobilized strain PCN-2 possessed high capability of removing NO and nitrogen dioxide (NO2) at O2 concentration of 0-10%. A biotrickling filter established with present strain achieved high NOx removal efficiencies of 91.94-96.74% at inlet NO concentration of 100-500ppm and O2 concentration of 0-10%, which implied promising potential applications in purifying NOx contaminated flue gas. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Development of the Aqueous Processes for Removing NOx from Flue Gases.

    Science.gov (United States)

    Chappell, Gilford A.

    A screening study was conducted to evaluate the capability of aqueous solutions to scrub NOx from the flue gases emitted by stationary power plants fired with fossil fuels. The report summarizes the findings of this laboratory program. The experimental program studied the following media for absorption of NOx from flue gases containing no NOx:…

  16. A kinetic sensitivity analysis for the SO2 and NOx removal using the electron beam technology

    Science.gov (United States)

    Zwolińska, Ewa; Gogulancea, Valentina; Sun, Yongxia; Lavric, Vasile; Chmielewski, Andrzej

    2017-09-01

    The mathematical modeling of the phenomena taking place during the electron beam flue gas treatment is a complex endeavor due to the different time scales of the processes occurring as accelerated electrons are bombarding the flue gas. The paper presents a complex kinetic model for these gas phase interactions, consisting of 1034 chemical reactions with the participation of 115 reactive species. The mathematical model couples the complex gas phase kinetics with a liquid phase kinetic model, taking into account the nucleation and condensation phenomena occurring due to the presence of sulfuric acid. The modeling results for both coupled and uncoupled gas phase kinetics are validated against a set of literature experimental data with satisfactory outcome. The work aims to identify the most important chemical reactions influencing the pollutants removal, proposing a sensitivity analysis using the concept of generated entropy. To the best of the authors' knowledge a sensitivity analysis of this extent has not been performed for the electron beam flue gas treatment. The results of this analysis emphasize the link between the removal efficiencies of NOx and SO2, the importance of hydroxyl radicals and can aid in future model reduction efforts.

  17. Effect of UV on De-NOx performance and microbial community of a hybrid catalytic membrane biofilm reactor

    Science.gov (United States)

    Chen, Zhouyang; Huang, Zhensha; He, Yiming; Xiao, Xiaoliang; Wei, Zaishan

    2018-02-01

    The hybrid membrane catalytic biofilm reactor provides a new way of flue gas denitration. However, the effects of UV on denitrification performance, microbial community and microbial nitrogen metabolism are still unknown. In this study, the effects of UV on deNO x performance, nitrification and denitrification, microbial community and microbial nitrogen metabolism of a bench scale N-TiO2/PSF hybrid catalytic membrane biofilm reactor (HCMBR) were evaluated. The change from nature light to UV in the HCMBR leads to the fall of NO removal efficiency of HCMBR from 92.8% to 81.8%. UV affected the microbial community structure, but did not change microbial nitrogen metabolism, as shown by metagenomics sequencing method. Some dominant phyla, such as Gammaproteobacteria, Bacteroidetes, Firmicutes, Actinobacteria, and Alphaproteobacteria, increased in abundance, whereas others, such as Proteobacteria and Betaproteobacteria, decreased. There were nitrification, denitrification, nitrogen fixation, and organic nitrogen metabolism in the HCMBR.

  18. Simultaneous removal of SO2 and NOX with ammonia absorbent in a packed column

    International Nuclear Information System (INIS)

    Jia, Yong; Du, Daqian; Zhang, Xinxi; Ding, Xilou; Zhong, Oin

    2013-01-01

    Catalytic oxidation of NO followed by simultaneous removal of SO 2 and NO X with ammonia is a promising method for control of coal-fired flue gas pollutants. We investigated simultaneous absorption of SO 2 and NO X in a packed column with ammonia, and found that SO 2 and NO X could promote absorption with each other in the process of simultaneous removal SO 2 and NO X . The removal efficiency of SO 2 and NO X was, respectively, about 98% and 70.9% at pH 5.5, temperature 323.15 K, SO 2 concentration 1,800x10 −6 , NO X concentration 400x10 −6 and m NO2 /m NO 1 in our experimental system. The experimental results also show that the formation of sulfite oxidized by reacting with dissolved NO 2 and the molar ratio of sulfite to total sulfur is more than 0.8 in the solution. Accordingly, the energy consumption for sulfite oxidation would be greatly reduced in the process of simultaneous desulfurization and denitrification with ammonia

  19. Catalytic reduction of NOx in gasoline engine exhaust over copper- and nickel-exchanged X-zeolite catalysts

    International Nuclear Information System (INIS)

    Bhattacharyya, S.; Das, R.K.

    2001-01-01

    Catalytic removal of NO x in engine exhaust gases can be accomplished by non-selective reduction, selective reduction and decomposition. Noble metals are extensively used for non-selective reduction of NO x and up to 90% of engine NO x emissions can be reduced in a stoichiometric exhaust. This requirement of having the stoichiometric fuel-air ratio acts against efficiency improvement of engines. Selective NO x reduction in the presence of different reductants such as, NH 3 , urea or hydrocarbons, requires close control of the amount of reductant being injected which otherwise may be emitted as a pollutant. Catalytic decomposition is the best option for NO x removal. Nevertheless, catalysts which are durable, economic and active for NO x reduction at normal engine exhaust temperature ranges are still being investigated. Three catalysts based on X-zeolite have been developed by exchanging the Na+ ion with copper, nickel and copper-nickel metal ions and applied to the exhaust of a stationary gasoline engine to explore their potential for catalytic reduction of NO x under a wide range of engine and exhaust conditions. Some encouraging results have been obtained. The catalyst Cu-X exhibits much better NO x reduction performance at any temperature in comparison to Cu-Ni-X and Ni-X; while Cu-Ni-X catalyst exhibits slightly better performance than Ni-X catalyst. Maximum NO x efficiency achieved with Cu-X catalyst is 59.2% at a space velocity (sv) of 31 000 h -1 ; while for Cu-Ni-X and Ni-X catalysts the equivalent numbers are 60.4% and 56% respectively at a sv of 22 000 h -1 . Unlike noble metals, the doped X-zeolite catalysts exhibit significant NO x reduction capability for a wide range of air/fuel ratio and with a slower rate of decline as well with increase in air/fuel ratio. (author)

  20. Analysis of the state and size of silver on alumina in effective removal of NOx from oxygen rich exhaust gas

    Czech Academy of Sciences Publication Activity Database

    Arve, K.; Klingstedt, F.; Eränen, K.; Murzin, D. Yu.; Čapek, Libor; Dědeček, Jiří; Sobalík, Zdeněk; Wichterlová, Blanka; Svennerberg, K.; Wallenberg, L. R.; Bovin, J.-O.

    2006-01-01

    Roč. 6, č. 4 (2006), s. 1076-1083 ISSN 1533-4880 R&D Projects: GA AV ČR 1ET400400413 Grant - others:European Union(XE) GR5D-CT 2001-00595 Institutional research plan: CEZ:AV0Z40400503 Keywords : silver * exhaust gas * removal of NOx Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.194, year: 2006

  1. Heteropoly acid promoted catalyst for SCR of NOx with ammonia

    DEFF Research Database (Denmark)

    2012-01-01

    The present invention concerns the selective removal of nitrogen oxides (NOx) from gases. In particular, the invention concerns a process, a highly alkali metal resistant heteropoly acid promoted catalyst and the use of said catalyst for removal of NOx from exhaust or flue gases, said gases...... comprising alkali or earth alkali metals. Such gases comprise for example flue gases arising from the burning of biomass, combined biomass and fossil fuel, and from waste incineration units. The process comprises the selective catalytic reduction (SCR) of NOx, such as nitrogen dioxide (NO2) and nitrogen...

  2. Adsortion-catalytic method for removing carbon monoxide from gas streams and catalysts for that method

    Energy Technology Data Exchange (ETDEWEB)

    Vlasenko, V.M.; Solov`ev, S.A.; Belokleitseva, G.M.

    1992-07-20

    Effective catalysts have been developed for the adsorption-catalytic removal of carbon monoxide from gases; a method of adsorption-catalytic removal of carbon monoxide from gases over a manganese oxide catalyst on a mordenite carrier which permits purification with almost no increase in gas temperature. A procedure for regeneration of the catalyst which ensures reproducibility of the adsorption process. 11 refs., 2 figs., 2 tabs.

  3. Diesel emission control: Catalytic filters for particulate removal

    Directory of Open Access Journals (Sweden)

    Debora Fino

    2007-01-01

    Full Text Available The European diesel engine industry represents a vital sector across the Continent, with more than 2 million direct work positions and a turnover of over 400 billion Euro. Diesel engines provide large paybacks to society since they are extensively used to transport goods, services and people. In recent years increasing attention has been paid to the emissions from diesel engines which, like gasoline engine emissions, include carbon monoxide (CO, hydrocarbons (HC and oxides of nitrogen (NOx. Diesel engines also produce significant levels of particulate matter (PM, which consists mostly of carbonaceous soot and a soluble organic fraction (SOF of hydrocarbons that have condensed on the soot.

  4. Catalytic tar removal from biomass producer gas with secondary air

    Energy Technology Data Exchange (ETDEWEB)

    Lammers, G.; Beenackers, A.A.C.M. [University of Groningen (Netherlands). Dept. of Chemical Engineering; Corella, J. [Universidad Complutense, Madrid (Spain)

    1997-12-31

    The effect of air addition on biomass tar conversion in catalytic packed bed crackers was studied using both an isothermal micro reactor and a fluidised bed bench scale biomass gasification set up with down stream tar crackers. The micro reactor was applied for experiments with artificial biomass producer gas containing naphthalene as a model tar compound. Experiments were carried out with inert silica and catalytically active calcined dolomite bed material both with and without air addition. Experimental results with real tar from the fluidised bed bench scale gasification set up were in qualitative agreement with results from the micro reactor experiments. (author)

  5. Catalytic pleat filter bags for combined particulate separation and nitrogen oxides removal from flue gas streams

    International Nuclear Information System (INIS)

    Park, Young Ok; Choi, Ho Kyung

    2010-01-01

    The development of a high temperature catalytically active pleated filter bag with hybrid filter equipment for the combined removal of particles and nitrogen oxides from flue gas streams is presented. A special catalyst load in stainless steel mesh cartridge with a high temperature pleated filter bag followed by optimized catalytic activation was developed to reach the required nitrogen oxides levels and to maintain the higher collection efficiencies. The catalytic properties of the developed high temperature filter bags with hybrid filter equipment were studied and demonstrated in a pilot scale test rig and a demonstration plant using commercial scale of high temperature catalytic pleated filter bags. The performance of the catalytic pleated filter bags were tested under different operating conditions, such as filtration velocity and operating temperature. Moreover, the cleaning efficiency and residual pressure drop of the catalyst loaded cartridges in pleated filter bags were tested. As result of theses studies, the optimum operating conditions for the catalytic pleated filter bags are determined. (author)

  6. Modelling study of NOx removal in oil-fired waste off-gases under electron beam irradiation

    Science.gov (United States)

    Zwolińska, Ewa; Sun, Yongxia; Chmielewski, A. G.; Nichipor, H.; Bulka, S.

    2015-08-01

    Computer simulations for high concentration of NOx removal from oil-fired waste off-gases under electron beam irradiation were carried out by using the Computer code "Kinetic" and GEAR method. 293 reactions involving 64 species were used for the modelling calculations. The composition of simulated oil-fired off-gas was the same as the experimental conditions. The calculations were made for following system: (75.78% N2+11.5% CO2+8.62% H2O+4.1% O2), NOx concentration varies from 200 ppm to 1500 ppm. Calculation results qualitatively agree with the experimental results. Furthermore the influence of temperature, SO2 concentration and ammonia addition is discussed.

  7. deNOx catalysts for biomass combustion

    DEFF Research Database (Denmark)

    Kristensen, Steffen Buus

    The present thesis revolves around the challenges involved in removal of nitrogen oxides in biomass fired power plants. Nitrogen oxides are unwanted byproducts formed to some extent during almost any combustion. In coal fired plants these byproducts are removed by selective catalytic reduction......, however the alkali in biomass complicate matters. Alkali in biomass severely deactivates the catalyst used for the selective catalytic reduction in matter of weeks, hence a more alkali resistant catalyst is needed. In the thesis a solution to the problem is presented, the nano particle deNOx catalyst...

  8. Preparation and Performance of Modified Red Mud-Based Catalysts for Selective Catalytic Reduction of NOx with NH3

    Directory of Open Access Journals (Sweden)

    Jingkun Wu

    2018-01-01

    Full Text Available Bayer red mud was selected, and the NH3-SCR activity was tested in a fixed bed in which the typical flue gas atmosphere was simulated. Combined with XRF, XRD, BET, SEM, TG and NH3-Temperature Programmed Desorption (TPD characterization, the denitration characteristics of Ce-doped red mud catalysts were studied on the basis of alkali-removed red mud. The results showed that typical red mud was a feasible material for denitration catalyst. Acid washing and calcining comprised the best treatment process for raw red mud, which reduced the content of alkaline substances, cleared the catalyst pore and optimized the particle morphology with dispersion. In the temperature range of 300–400 °C, the denitrification efficiency of calcined acid washing of red mud catalyst (ARM was more than 70%. The doping of Ce significantly enhanced NH3 adsorption from weak, medium and strong acid sites, reduced the crystallinity of α-Fe2O3 in ARM, optimized the specific surface area and broadened the active temperature window, which increased the NOx conversion rate by an average of nearly 20% points from 250–350 °C. The denitration efficiency of Ce0.3/ARM at 300 °C was as high as 88%. The optimum conditions for the denitration reaction of the Ce0.3/ARM catalyst were controlled as follows: Gas Hourly Space Velocity (GHSV of 30,000 h−1, O2 volume fraction of 3.5–4% and the NH3/NO molar ratio ([NH3/NO] of 1.0. The presence of SO2 in the feed had an irreversible negative effect on the activity of the Ce0.3/ARM catalyst.

  9. Anatase TiO2 nanotube arrays and titania films on titanium mesh for photocatalytic NOx removal and water cleaning

    Czech Academy of Sciences Publication Activity Database

    Motola, M.; Satrapinskyy, L.; Roch, T.; Šubrt, Jan; Kupčík, Jaroslav; Klementová, Mariana; Jakubičková, M.; Peterka, F.; Plesch, G.

    2017-01-01

    Roč. 287, JUN (2017), s. 59-64 ISSN 0920-5861. [European meeting on Solar Chemistry and Photocatalysis: Environmental Applications (SPEA) /9./. Strasbourg, 13.06.2016-17.06.2016] R&D Projects: GA ČR(CZ) GA14-20744S; GA MŠk(CZ) 7AMB14SK178 Institutional support: RVO:61388980 Keywords : Titanium mesh * Anatase nanotubes array * Liquid state deposition * NOx removal * Photocatalysis Subject RIV: CA - Inorganic Chemistry OBOR OECD: Inorganic and nuclear chemistry Impact factor: 4.636, year: 2016

  10. Effect of SO2 on the performance of Ag-Pd/Al2O3 for the selective catalytic reduction of NOx with C2H5OH.

    Science.gov (United States)

    Xie, Shu-xia; Yu, Yun-bo; Wang, Jin; He, Hong

    2006-01-01

    The influence of SO2 on the performance of Ag-Pd/Al2O3 for the selective catalytic reduction (SCR) of NOx with C2H5OH was investigated experimentally. The activity test results suggest that Ag-Pd/Al203 shows a small activity loss in the presence of SO2 when using C2H5OH as a reductant. In situ DRIFTS spectra show that the activity loss originates from the formation of surface sulphate species on the Ag-Pd/Al2O3. The surface sulphate species formation inhibits the formation of nitrate, whereas hardly changes the partial oxidation of C2HsOH. Compared with the NOx reduction by C3H6 an obvious suppression of the surface sulphate species formation was observed by DRIFTS experiment when using C2H50H as a reductant. This phenomenon reveals the better catalytic performance and strong SO2 tolerance of Ag-Pd/Al2O3-C2H5OH system.

  11. Visible-light-driven N-(BiO)2CO3/Graphene oxide composites with improved photocatalytic activity and selectivity for NOx removal

    Science.gov (United States)

    Chen, Meijuan; Huang, Yu; Yao, Jie; Cao, Jun-ji; Liu, Yuan

    2018-02-01

    N-doped (BiO)2CO3 (NBOC)/graphene oxide (GO) composite obtained from three-dimensional hierarchical microspheres is successfully synthesized by one-pot hydrothermal method for the first time. In this synthesis, citrate ion plays a critical role in N doping. The obtained samples are used to degrade gaseous nitrogen oxides (NOx) at parts-per-billion (ppb) level under visible-light irradiation. NBOC-GO composite with 1.0 wt% graphene oxide (GO) displays the highest photocatalytic NO removal efficiency, which is 4.3 times higher than that of pristine (BiO)2CO3. Moreover, NBOC-GO composite significantly inhibits toxic NO2 intermediate production, indicating its high selectivity for NO conversion. Compared with regular GO, N doping considerably improves the catalytic performance of NBOC-GO composite, which increases NO removal by 74.6% and fully inhibits NO2 generation. The improved photocatalytic activity is mainly ascribed to extended optical absorption ability and enhanced separation efficiency of photogenerated charge carriers over NBOC-GO composite. Both results of electron spin resonance and theoretical analysis of band structure indicate that NO removal is dominated by oxidation with rad OH and rad O2- radicals. The photocatalytic activity improvement mechanism over the NBOC-GO composite is proposed accordingly based on systematic characterizations. This study demonstrates a feasible route to fabricating Bi-containing composites with high selectivity and stability for air pollution control and provides a new insight into the associated photocatalytic mechanisms.

  12. Catalytic removal of oxygen from biomass-derived syngas.

    Science.gov (United States)

    Yan, Qiangu; Wan, Caixia; Street, Jason; Yan, David W; Han, Jun; Yu, Fei

    2013-11-01

    Selective oxygen (O2) removal from wood-derived syngas was investigated over three types of ceria-modified alumina supported metal catalysts (i.e., Pt, Pd, and Cu). Complete O2 removal was observed with the Pt and Pd catalysts at a lower temperature than with the Cu catalyst. Gas hourly space velocity (GHSV) was another critical parameter affecting O2 removal, substantially reducing O2 conversion by all three catalysts at 4000 h(-1) or above. The Cu catalyst appeared to be most sensitive to GHSV. Among three catalysts, the Pd catalyst had the best performance on O2 removal. In addition to reaction conditions, CO2 and water vapor in the syngas also influenced O2 removal, both of which had adverse effects on O2 conversion. Stability tests indicated that both Pt and Pd catalysts were quite stable over a 300 h testing period while the Cu catalyst was deactivated after 50h and regenerated by elevating reaction temperature. Copyright © 2013 Elsevier Ltd. All rights reserved.

  13. High-efficiency removal of NOx using dielectric barrier discharge nonthermal plasma with water as an outer electrode

    Science.gov (United States)

    Dan, ZHAO; Feng, YU; Amin, ZHOU; Cunhua, MA; Bin, DAI

    2018-01-01

    With the rapid increase in the number of cars and the development of industry, nitrogen oxide (NOx) emissions have become a serious and pressing problem. This work reports on the development of a water-cooled dielectric barrier discharge reactor for gaseous NOx removal at low temperature. The characteristics of the reactor are evaluated with and without packing of the reaction tube with 2 mm diameter dielectric beads composed of glass, ZnO, MnO2, ZrO2, or Fe2O3. It is found that the use of a water-cooled tube reduces the temperature, which stabilizes the reaction, and provides a much greater NO conversion efficiency (28.8%) than that obtained using quartz tube (14.1%) at a frequency of 8 kHz with an input voltage of 6.8 kV. Furthermore, under equivalent conditions, packing the reactor tube with glass beads greatly increases the NO conversion efficiency to 95.85%. This is because the dielectric beads alter the distribution of the electric field due to the influence of polarization at the glass bead surfaces, which ultimately enhances the plasma discharge intensity. The presence of the dielectric beads increases the gas residence time within the reactor. Experimental verification and a theoretical basis are provided for the industrial application of the proposed plasma NO removal process employing dielectric bead packing.

  14. Theoretical Study of Methods for Improving the Energy Efficiency of NOx Removal from Diesel Exhaust Gases by Silent Discharge

    Science.gov (United States)

    Shoyama, Taiji; Yoshioka, Yoshio

    To improve the NO removal performance in silent discharge process, we investigated the influence of the physical parameters such as current density, channel radius and pulse duration of the one micro discharge under the constant reduced electric field strength. And influence of the micro discharges occurrence locations were also discussed. In order to analyze the NO removal process, we assumed that the pulse micro discharges occur repeatedly at the same location in static gas and that the chemical reactions induced by micro discharge forms many radicals, which react with pollutants and by-products. The conclusions we obtained are that lower current density, smaller discharge radius and shorter discharge duration improve NO removal efficiency. These results also mean that the lower discharge energy of the one micro discharge and the larger number of parallel micro discharges increase the NO removal performance. Therefore, to make the area of one micro discharge small is a desirable way to improve the NO removal performance. So we think that the glow like discharge might be more effective than the streamer like discharge mode. Next, using the two-dimensional model, which considered the influence of gas flow, we obtained a conclusion that the repeated micro discharges at different positions are very effective to increase the De-NOx performance. The reason is that the reaction of NO2+O→NO+O2 and ozone dissociation reactions are suppressed by the movement of the location of micro discharges.

  15. Re-acclimation performance and microbial characteristics of a thermophilic biofilter for NOx removal from flue gas.

    Science.gov (United States)

    Zhang, Shihan; Chen, Han; Xia, Yinfeng; Zhao, Jingkai; Liu, Nan; Li, Wei

    2015-08-01

    Currently, a novel chemical absorption-biological reduction (CABR) integrated process, employing Fe(II)EDTA as a solvent, is being under development to reduce the cost of NOx removal from flue gas. In this work, the NO removal profile, re-acclimation performance, and microbial characteristics in a thermophilic biofilter were investigated at the conditions typical to CABR process. The biofilter comprised of four layers of packing material with a surface area of 1200 m(2) m(-3). Experimental results revealed that the biofilter could remove 95 % of the fed NO at typical flue gas conditions. As the gas residence time varied from 90 to 15 s, the NO removal efficiency decreased from 100 to 56.5 % due to the NO mass transfer limitation. The longer period of the biofilter shutdown required more time for its re-acclimation. For example, after 8-day shutdown, the biofilter was re-acclimated in 32 h. Denaturing gradient gel electrophoresis analysis of PCR-amplified product showed that Pseudomonas, a group of denitrifier, was dominant in the biofilter. Because the Pseudomonas was abundant at the bottom layer of packed-bed, the bottom layer contributed to 60-70 % of the total NO removal. In addition, Pseudomonas gradually faded away along the gas flow path from the bottom to the top of biofilter, resulting in a significant decrease in NO removal at the other three packed-bed layers. These observed results will provide the process engineering and scale-up data with respect to the biofilter operations to help advance the CABR process to pilot-scale testing.

  16. Near-Zero Emissions Oxy-Combustion Flue Gas Purification Task 2: SOx/Nox/Hg Removal for High Sulfur Coal

    Energy Technology Data Exchange (ETDEWEB)

    Nick Degenstein; Minish Shah; Doughlas Louie

    2012-05-01

    The goal of this project is to develop a near-zero emissions flue gas purification technology for existing PC (pulverized coal) power plants that are retrofitted with oxy-combustion technology. The objective of Task 2 of this project was to evaluate an alternative method of SOx, NOx and Hg removal from flue gas produced by burning high sulfur coal in oxy-combustion power plants. The goal of the program was not only to investigate a new method of flue gas purification but also to produce useful acid byproduct streams as an alternative to using a traditional FGD and SCR for flue gas processing. During the project two main constraints were identified that limit the ability of the process to achieve project goals. 1) Due to boiler island corrosion issues >60% of the sulfur must be removed in the boiler island with the use of an FGD. 2) A suitable method could not be found to remove NOx from the concentrated sulfuric acid product, which limits sale-ability of the acid, as well as the NOx removal efficiency of the process. Given the complexity and safety issues inherent in the cycle it is concluded that the acid product would not be directly saleable and, in this case, other flue gas purification schemes are better suited for SOx/NOx/Hg control when burning high sulfur coal, e.g. this project's Task 3 process or a traditional FGD and SCR.

  17. Carbonates-based noble metal-free lean NOx trap catalysts MOx-K2CO3/K2Ti8O17 (M = Ce, Fe, Cu, Co) with superior catalytic performance

    Science.gov (United States)

    Zhang, Yuxia; You, Rui; Liu, Dongsheng; Liu, Cheng; Li, Xingang; Tian, Ye; Jiang, Zheng; Zhang, Shuo; Huang, Yuying; Zha, Yuqing; Meng, Ming

    2015-12-01

    A series of base metal-based lean NOx trap (LNT) catalysts MOx-K2CO3/K2Ti8O17 (M = Ce, Fe, Cu, Co) were synthesized by successive impregnations and employed for the storage and reduction of NOx in the emissions of lean-burn engines at 350 °C. The XRD and XANES/EXAFS results reveal that the active phases in the corresponding catalysts exist as CeO2, Fe2O3, CuO and Co3O4, respectively. Among all the catalysts, CoOx-K2CO3/K2Ti8O17 exhibits the best performance, which cannot only trap the NOx quickly and completely at lean condition, giving the highest storage capacity (3.32 mmol/g) reported so far, but also reduce the NOx at rich condition, showing a NOx reduction percentage as high as 99.0%. Meanwhile, this catalyst displays an ultralow NOx to N2O selectivity (0.3%) during NOx reduction. The excellent performance of CoOx-K2CO3/K2Ti8O17 results from its largest amount of surface active oxygen species as revealed by XPS, O2-TPD and NO-TPD. HRTEM, FT-IR and CO2-TPD results illustrate that several kinds of K species such as sbnd OK groups, K2O, surface carbonates and bulk or bulk-like carbonates coexist in the catalysts. Based upon the in situ DRIFTS results, the participation of K2CO3 in NOx storage is confirmed, and the predominant NOx storage species is revealed as bidentate nitrites formed via multiple kinetic pathways. The low cost and high catalytic performance of the CoOx-based LNT catalyst make it most promising for the substitution of noble metal-based LNT catalysts.

  18. Mechanism of NOx removal by electron beam process in the presence of scavengers

    International Nuclear Information System (INIS)

    Chmielewski, A.G.; Sun Yongxia; Zimek, Z.; Bulka, S.; Licki, J.

    2002-01-01

    In this study NO x removal efficiency, with/without SO 2 in electron beam flue gas treatment process, was evaluated in the presence of different additives: ammonia, water, and alcohol. It was found that NO x removal efficiency increased by 20% and in the presence of alcohol, more than 70% NO x was oxidized/reduced at 6 kGy for the initial concentration of 500 ppm NO. Humidity and ammonia addition increased the NO x removal efficiency but not more than 10%. Organic products and inorganic products were analyzed by a GC-MS and ion chromatography, respectively. The focus of this paper is on the mechanism that accounts for the increased efficiency in NO x removal

  19. Low concentration volatile organic pollutants removal in combined adsorber-desorber-catalytic reactor system

    Directory of Open Access Journals (Sweden)

    Arsenijević Zorana

    2008-01-01

    Full Text Available The removal of volatile organic compounds (VOCs from numerous emission sources is of crucial importance due to more rigorous demands on air quality. Different technologies can be used to treat the VOCs from effluent gases: absorption, physical adsorption, open flame combustion, thermal and catalytic incineration. Their appropriateness for the specific process depends on several factors such as efficiency, energy consumption, secondary pollution, capital investments etc. The distinctive features of the catalytic combustion are high efficiency and selectivity toward be­nign products, low energy consumption and absence of secondary polluti­on. The supported noble catalysts are widely used for catalytic incineration due to their low ignition temperatures and high thermal and chemical stability. In our combined system adsorption and desorption are applied in the spouted bed with draft tube (SBDT unit. The annular zone, loaded with sorbent, was divided in adsorption and desorption section. Draft tube enabled sorbent recirculation between sections. Combustion of desorbed gases to CO2 and water vapor are realized in additive catalytic reactor. This integrated device provided low concentrations VOCs removal with reduced energy consumption. Experiments were conducted on a pilot unit of 220 m3/h nominal capacity. The sorbent was activated carbon, type K81/B - Trayal Corporation, Krusevac. A sphere shaped commercial Pt/Al2O3 catalyst with "egg-shell" macro-distribution was used for the investigation of xylene deep oxidation. Within this paper the investigations of removal of xylene vapors, a typical pollutant in production of liquid pesticides, in combined adsorber/desorber/catalytic reactor system is presented.

  20. Enhanced catalytic activity over MIL-100(Fe) loaded ceria catalysts for the selective catalytic reduction of NOx with NH3 at low temperature

    International Nuclear Information System (INIS)

    Wang, Peng; Sun, Hong; Quan, Xie; Chen, Shuo

    2016-01-01

    Highlights: • Nano-ceria was successfully encapsulated into MIL-100(Fe) for the SCR of NO x . • The incorporated ceria in MIL-100(Fe) showed high content of chemisorbed oxygen. • The added ceria into MIL-100(Fe) improved the formation of adsorbed NO 2 species. • The addition of ceria into MIL-100(Fe) enhanced SCR activity at low temperature. - Abstract: The development of catalysts for selective catalytic reduction (SCR) reactions that are highly active at low temperatures and show good resistance to SO 2 and H 2 O is still a challenge. In this study, we have designed and developed a high-performance SCR catalyst based on nano-sized ceria encapsulated inside the pores of MIL-100(Fe) that combines excellent catalytic power with a metal organic framework architecture synthesized by the impregnation method (IM). Transmission electron microscopy (TEM) revealed the encapsulation of ceria in the cavities of MIL-100(Fe). The prepared IM-CeO 2 /MIL-100(Fe) catalyst shows improved catalytic activity both at low temperatures and throughout a wide temperature window. The temperature window for 90% NO x conversion ranges from 196 to 300 °C. X-ray photoelectron spectroscopy (XPS) and in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFT) analysis indicated that the nano-sized ceria encapsulated inside MIL-100(Fe) promotes the production of chemisorbed oxygen on the catalyst surface, which greatly enhances the formation of the NO 2 species responsible for fast SCR reactions.

  1. Electrochemical waste clean-up process for simultaneous removal of SO2 and NOx

    International Nuclear Information System (INIS)

    Juettner, K.; Kreysa, G.; Kleifges, K.H.; Rottmann, R.

    1994-01-01

    Based on the principles of electrochemical exhaust purification, a new process for electrochemical simultaneous removal of SO 2 and NO x is presented. It combines an ''cruter call'' process for NO x reduction with dithionite as homogeneous redox mediator with an ''inner cell'' process for direct oxidation of SO 2 in the anodic space of an electrochemical cell. Absorption experiments for NO x and SO 2 were carried out in separate laboratory scale electrochemical cells. Results are presented. (orig./BBR) [de

  2. An Improved Flexible Solar Thermal Energy Integration Process for Enhancing the Coal-Based Energy Efficiency and NOx Removal Effectiveness in Coal-Fired Power Plants under Different Load Conditions

    Directory of Open Access Journals (Sweden)

    Yu Han

    2017-09-01

    Full Text Available An improved flexible solar-aided power generation system (SAPG for enhancing both selective catalytic reduction (SCR de-NOx efficiency and coal-based energy efficiency of coal-fired power plants is proposed. In the proposed concept, the solar energy injection point is changed for different power plant loads, bringing about different benefits for coal-fired power generation. For partial/low load, solar energy is beneficially used to increase the flue gas temperature to guarantee the SCR de-NOx effectiveness as well as increase the boiler energy input by reheating the combustion air. For high power load, solar energy is used for saving steam bleeds from turbines by heating the feed water. A case study for a typical 1000 MW coal-fired power plant using the proposed concept has been performed and the results showed that, the SCR de-NOx efficiency of proposed SAPG could increase by 3.1% and 7.9% under medium load and low load conditions, respectively, as compared with the reference plant. The standard coal consumption rate of the proposed SAPG could decrease by 2.68 g/kWh, 4.05 g/kWh and 6.31 g/kWh for high, medium and low loads, respectively, with 0.040 USD/kWh of solar generated electricity cost. The proposed concept opens up a novel solar energy integration pattern in coal-fired power plants to improve the pollutant removal effectiveness and decrease the coal consumption of the power plant.

  3. Improving g-C3N4 photocatalysis for NOx removal by Ag nanoparticles decoration

    International Nuclear Information System (INIS)

    Sun, Yanjuan; Xiong, Ting; Ni, Zilin; Liu, Jie; Dong, Fan; Zhang, Wei; Ho, Wing-Kei

    2015-01-01

    Graphical abstract: Ag/g-C 3 N 4 nanocomposites were prepared via a facile method for enhanced photocatalytic NO x removal due to surface plasmon resonance of Ag. - Highlights: • The Ag/g-C 3 N 4 nanocomposites were prepared using urea as the precursor. • The Ag/g-C 3 N 4 nanocomposites were applied in removal of NO x in air. • The Ag nanoparticles enhanced the photocatalytic activity of g-C 3 N 4 . • The surface plasmon resonance of Ag played a key role in photocatalysis. - Abstract: In order to overcome the intrinsic drawback of pristine g-C 3 N 4 , we prepared g-C 3 N 4 nanosheets with enhanced photocatalytic performance by Ag nanoparticles decoration using urea as the precursor. It was revealed that the monodispersed Ag nanoparticles were deposited on the surface of g-C 3 N 4 nanosheets. The Ag/g-C 3 N 4 nanocomposites were applied in removal of NO x in air under visible light irradiation. The results showed that the decoration of Ag nanoparticles not only enhanced the photocatalytic activity of g-C 3 N 4 nanosheets, but also benefited the oxidation of NO to final products. The increased visible light absorption arising from the surface plasmon resonance of Ag and improved separation and transfer of photoinduced carriers over Ag/g-C 3 N 4 composites were demonstrated by the UV–vis diffuse reflectance spectra and photoluminescence spectra, respectively. It was therefore proposed that the enhanced photocatalytic activity of Ag/g-C 3 N 4 composites could be attributed to the extended light response range and enhanced charge separation due to the introduction of Ag nanoparticles.

  4. AMMONIA-FREE NOx CONTROL SYSTEM

    Energy Technology Data Exchange (ETDEWEB)

    Song Wu; Zhen Fan; Andrew H. Seltzer; Richard G. Herman

    2006-06-01

    This report describes a novel NOx control system that has the potential to drastically reduce cost, and enhance performance, operation and safety of power plant NOx control. The new system optimizes the burner and the furnace to achieve very low NOx levels and to provide an adequate amount of CO, and uses the CO for reducing NO both in-furnace and over a downstream AFSCR (ammonia-free selective catalytic reduction) reactor. The AF-SCR combines the advantages of the highly successful SCR technology for power plants and the TWC (three-way catalytic converter) widely used on automobiles. Like the SCR, it works in oxidizing environment of combustion flue gas and uses only base metal catalysts. Like the TWC, the AF-SCR removes NO and excess CO simultaneously without using any external reagent, such as ammonia. This new process has been studied in a development program jointed funded by the US Department of Energy and Foster Wheeler. The report outlines the experimental catalyst work performed on a bench-scale reactor, including test procedure, operating conditions, and results of various catalyst formulations. Several candidate catalysts, prepared with readily available transition metal oxides and common substrate materials, have shown over 80-90% removal for both NO and CO in oxidizing gas mixtures and at elevated temperatures. A detailed combustion study of a 400 MWe coal-fired boiler, applying computational fluid dynamics techniques to model boiler and burner design, has been carried out to investigate ways to optimize the combustion process for the lowest NOx formation and optimum CO/NO ratios. Results of this boiler and burner optimization work are reported. The paper further discusses catalyst scale-up considerations and the conceptual design of a 400 MWe size AF-SCR reactor, as well as economics analysis indicating large cost savings of the ammonia-free NOx control process over the current SCR technology.

  5. Supported, Alkali-Promoted Cobalt Oxide Catalysts for NOx Removal from Coal Combustion Flue Gases

    Energy Technology Data Exchange (ETDEWEB)

    Morris D. Argyle

    2005-12-31

    A series of cobalt oxide catalysts supported on alumina ({gamma}-Al{sub 2}O{sub 3}) were synthesized with varying contents of cobalt and of added alkali metals, including lithium, sodium, potassium, rubidium, and cesium. Unsupported cobalt oxide catalysts and several cobalt oxide catalysts supported ceria (CeO{sub 2}) with varying contents of cobalt with added potassium were also prepared. The catalysts were characterized with UV-visible spectroscopy and were examined for NO{sub x} decomposition activity. The CoO{sub x}/Al{sub 2}O{sub 3} catalysts and particularly the CoO{sub x}/CeO{sub 2} catalysts show N{sub 2}O decomposition activity, but none of the catalysts (unsupported Co{sub 3}O{sub 4} or those supported on ceria or alumina) displayed significant, sustained NO decomposition activity. For the Al{sub 2}O{sub 3}-supported catalysts, N{sub 2}O decomposition activity was observed over a range of reaction temperatures beginning about 723 K, but significant (>50%) conversions of N{sub 2}O were observed only for reaction temperatures >900 K, which are too high for practical commercial use. However, the CeO{sub 2}-supported catalysts display N{sub 2}O decomposition rates similar to the Al{sub 2}O{sub 3}-supported catalysts at much lower reaction temperatures, with activity beginning at {approx}573 K. Conversions of >90% were achieved at 773 K for the best catalysts. Catalytic rates per cobalt atom increased with decreasing cobalt content, which corresponds to increasing edge energies obtained from the UV-visible spectra. The decrease in edge energies suggests that the size and dimensionality of the cobalt oxide surface domains increase with increasing cobalt oxide content. The rate data normalized per mass of catalyst that shows the activity of the CeO{sub 2}-supported catalysts increases with increasing cobalt oxide content. The combination of these data suggest that supported cobalt oxide species similar to bulk Co{sub 3}O{sub 4} are inherently more active than

  6. An Assessment of the Technical Readiness of the Vapor Phase Catalytic Ammonia Removal Process (VPCAR) Technology

    Science.gov (United States)

    Flynn, Michael

    2000-01-01

    This poster provides an assessment of the technical readiness of the Vapor Phase Catalytic Ammonia Removal Process (VPCAR). The VPCAR technology is a fully regenerative water recycling technology designed specifically for applications such as a near term Mars exploration mission. The VPCAR technology is a highly integrated distillation/catalytic oxidation based water processor. It is designed to accept a combined wastewater stream (urine, condensate, and hygiene) and produces potable water in a single process step which requires -no regularly scheduled re-supply or maintenance for a 3 year mission. The technology is designed to be modular and to fit into a volume comparable to a single International Space Station Rack (when sized for a crew of 6). This poster provides a description of the VPCAR technology and a summary of the current performance of the technology. Also provided are the results of two separate NASA sponsored system trade studies which investigated the potential payback of further development of the VPCAR technology.

  7. Review of state of the art technologies of selective catalytic reduction of NOx from diesel engine exhaust

    International Nuclear Information System (INIS)

    Guan, Bin; Zhan, Reggie; Lin, He; Huang, Zhen

    2014-01-01

    Increasingly stringent emission legislations, such as US 2010 and Euro VI, for NO x in mobile applications will require the use of intensification of NO x reduction aftertreatment technologies, such as the selective catalytic reduction (SCR). Due to the required higher deNO x efficiency, a lot of efforts have recently been concentrated on the optimization of the SCR systems for broadening the active deNO x temperature window as widely as possible, especially at low temperatures, enhancing the catalysts durability, and reducing the cost of the deNO x system. This paper provides a comprehensive overview of the state-of-the-art SCR technologies, including the alternative ammonia generation from the solid reductants, Vanadium-based, Cu-zeolite (CuZ) and Fe-zeolite (FeZ) based, and the novel chabazite zeolite with small pore size SCR catalysts. Furthermore, the progresses of the highly optimized hybrid approaches, involving combined CuZ and FeZ SCR, passive SCR, integration of DOC + (DPF, SCR), as well as SCR catalyst coated on DPF (referred as SCRF hereinafter) systems are well discussed. Even though SCR technology is considered as the leading NO x aftertreatment technology, attentions have been paid to the adverse by-products, such as NH 3 and N 2 O. Relevant regulations have been established to address the issues. - Highlights: •The review of state of the art technologies of selective catalytic reduction of NO x . •The mainstream V-based, Cu- and Fe-zeolite, and chabazite catalysts are illustrated. •The development of highly optimized hybrid integration SCR systems are analyzed. •The by-products of SCR systems and the corresponding regulations are discussed. •The future perspectives of the advanced SCR technologies are described

  8. Combined fast selective reduction using Mn-based catalysts and nonthermal plasma for NOx removal.

    Science.gov (United States)

    Chen, Jun Xiang; Pan, Kuan Lun; Yu, Sheng Jen; Yen, Shaw Yi; Chang, Moo Been

    2017-09-01

    In this study, the concept of fast SCR for NO reduction with NH 3 as reducing agent is realized via the combination of nonthermal plasma (NTP) with Mn-based catalyst. Experimental results indicate that 10% wt. Mn-Ce-Ni/TiO 2 possesses better physical and chemical properties of surface, resulting in higher NO removal efficiency if compared with 10% wt. Mn-Ce/TiO 2 and 10% wt. Mn-Ce-Cu/TiO 2 . Mn-Ce-Ni/TiO 2 of 10% wt. achieves 100% NO x conversion at 150 °C, while 10% wt. Mn-Ce/TiO 2 and 10% wt. Mn-Ce-Cu/TiO 2 need to be operated at a temperature above 200 °C for 100% NO x conversion. However, NO conversion achieved with 10% wt. Mn-Ce-Ni/TiO 2 is significantly reduced as H 2 O (g) and SO 2 are introduced into the SCR system simultaneously. Further, two-stage system (SCR with DBD) is compared with the catalyst-alone for NO x conversion and N 2 selectivity. The results indicate that 100% NO x conversion can be achieved with two-stage system at 100 °C, while N 2 selectivity reaches 80%. Importantly, NO x conversion achieved with two-stage system could maintain >95% in the presence of C 2 H 4 , CO, SO 2 , and H 2 O (g) , indicating that two-stage system has better tolerance for complicated gas composition. Overall, this study demonstrates that combining NTP with Mn-based catalyst is effective in reducing NO x emission at a low temperature (≤200 °C) and has good potential for industrial application.

  9. Catalytic

    Directory of Open Access Journals (Sweden)

    S.A. Hanafi

    2014-03-01

    Full Text Available A series of dealuminated Y-zeolites impregnated by 0.5 wt% Pt catalysts promoted by different amounts of Ni, Pd or Cr (0.3 and 0.6 wt% were prepared and characterized as hydrocracking catalysts. The physicochemical and structural characterization of the solid catalysts were investigated and reported through N2 physisorption, XRD, TGA-DSC, FT-IR and TEM techniques. Solid catalysts surface acidities were investigated through FT-IR spectroscopy aided by pyridine adsorption. The solid catalytic activities were evaluated through hydroconversion of n-hexane and n-heptane employing micro-catalytic pulse technique directly connected to a gas chromatograph analyzer. The thermal stability of the solids was also investigated up to 800 °C. Crystallinity studies using the XRD technique of all modified samples proved analogous to the parent Y-zeolite, exhibiting nearly an amorphous and microcrystalline character of the second metal oxides. Disclosure of bimetallic catalysts crystalline characterization, through XRD, was not viable. The nitrogen adsorption–desorption isotherms for all samples concluded type I adsorption isotherms, without any hysteresis loop, indicating that the entire pore system is composed of micropores. TEM micrographs of the solid catalysts demonstrate well-dispersed Pt, Ni and Cr nanoparticles having sizes of 2–4 nm and 7–8 nm, respectively. The catalytic activity results indicate that the bimetallic (0.5Pt–0.3Cr/D18H–Y catalyst is the most active towards n-hexane and n-heptane isomerization while (0.5Pt–0.6Ni/D18H–Y catalyst can be designed as most suitable as a cracking catalyst.

  10. Methods for sulfate removal in liquid-phase catalytic hydrothermal gasification of biomass

    Science.gov (United States)

    Elliott, Douglas C; Oyler, James

    2013-12-17

    Processing of wet biomass feedstock by liquid-phase catalytic hydrothermal gasification must address catalyst fouling and poisoning. One solution can involve heating the wet biomass with a heating unit to a pre-treatment temperature sufficient for organic constituents in the feedstock to decompose, for precipitates of inorganic wastes to form, for preheating the wet feedstock in preparation for subsequent removal of soluble sulfate contaminants, or combinations thereof. Processing further includes reacting the soluble sulfate contaminants with cations present in the feedstock material to yield a sulfate-containing precipitate and separating the inorganic precipitates and/or the sulfate-containing precipitates out of the wet feedstock. Having removed much of the inorganic wastes and the sulfate contaminants that can cause poisoning and fouling, the wet biomass feedstock can be exposed to the heterogenous catalyst for gasification.

  11. Survey the Efficiency of Catalytic Ozonation Process with Carbosieve in the Removal of Benzene from Polluted Air Stream

    Directory of Open Access Journals (Sweden)

    M. Samarghandi

    2014-01-01

    Full Text Available Introduction & Objective: Benzene is one of the most common volatile organic compounds in the indoor and outdoor environments that has always been considered as one of the causes of air pollution. Thus before being discharged to the environment, it must be treated from pol-luted air stream. The aim of this study was to determine the efficiency of catalytic ozonation process with carbosieve in the removal of benzene from polluted air stream. Materials & Methods: The study was experimental in which catalytic ozonation process with carbosieve was used in the removal of benzene from polluted air stream. The experiments were carried out in a reactor with continuous system and the results of catalytic ozonation were compared with the results of single ozonation and carbosieve adsorbent .The sampling, benzene analyzing and determining of ozone concentration in samples were done with 1501 NMAM method by GC equipped with FID detector and iodometry , respectively. Results: The results of this study showed that the removal effectiveness of single ozonation process is averagely less than 19%. Also the efficiency of absorbent decreased with the con-centration increase of benzene.The increase ratio of efficiency in catalytic ozonation process to efficiency of carbosieve adsorbent was averagely 45%. Conclusion: With regard to high efficiency of catalytic ozonation process and increasing the benzene removal , the catalytic ozonation process is suggested as a promising and alternative technology for elimination of VOCs from the polluted air stream. (Sci J Hamadan Univ Med Sci 2014; 20 (4:303-311

  12. Assessment and identification of some novel NOx reducing reagents for SNCR process

    International Nuclear Information System (INIS)

    Mahmood, A.; Javed, M.T.; Irfan, N.; Hamid, A. and K.; Waheed, K.

    2009-01-01

    Nitrogen oxides (NOx) are one of the most hazardous air pollutants arising from the combustion processes. Because of the implementation of strict emission limits many NOx removal technologies have been developed. In the present work post combustion NOx removal technique that is Selective Non-Catalytic Reduction (SNCR) has been investigated in a pilot scale 150 kW combustion rig facility. Investigation has been performed using some novel NOx reducing reagents like urea, ammonium carbonate and mixture of their 50%-50% aqueous solution within the temperature range of 700 to 1200 deg. C., at 1.1% excess oxygen and background NOx level of 500 ppm. The effects of these reagents were determined in term of their temperature characteristics and molar ratio. Among the reducing reagents used urea solution gave the highest NOx removal efficiency (81%) and was attractive due to its superior high temperature (1000 to 1150 deg. C) performance, ammonium carbonate was more effective at lower temperature range (850 to 950 deg. C) though its efficiency (32%) was lower than urea, while 50-50% solution of urea and ammonium carbonate gave higher efficiency than ammonium carbonate but slightly lesser than urea within a wide temperature range (875 to 1125 deg. C). It was also observed that the NOx removal efficiency was increased with increasing the molar ratio. (author)

  13. Promotional effect of tungsten-doped CeO{sub 2}/TiO{sub 2} for selective catalytic reduction of NOx with ammonia

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Dong Wook; Hong, Sung Chang, E-mail: schong@kgu.ac.kr

    2015-11-30

    Graphical abstract: - Highlights: • Catalysts were prepared by adding various metals to Ce/Ti to improve the activity. • The Ce{sup 3+} ratio of 10Ce/Me/Ti was proportional to the SCR activity of the catalyst. • When tungsten was added to 10Ce/Ti, an excellent SO{sub 2} resistance was displayed. - Abstract: We examined the effects that the physicochemical properties of Ce/Me/Ti catalysts had on the selective catalytic reduction (SCR) activity after various metals (W, Mo, and La) were added to non-vanadium-based catalysts in order to improve NH{sub 3}–SCR activity. We studied the properties of the catalysts through the use of physiochemical techniques, including Brunauer–Emmett–Teller (BET) surface area analysis, X-ray diffraction (XRD), H{sub 2} temperature-programmed reduction (H{sub 2}-TPR), X-ray photoelectron spectroscopy (XPS) transmission infrared spectroscopy (IR), and inductively coupled plasma optic emission spectroscopy (ICP). The catalytic activity tests of the Ce/Ti catalysts with various ceria loadings revealed that the Ce/Ti with 10 wt.% ceria (10Ce/Ti) exhibited excellent activity. Thus, various metals were added to the 10Ce/Ti. The tungsten-doped 10Ce/Ti catalyst exhibited the highest activity (10Ce/W/Ti: Ce was deposited after tungsten had been deposited on TiO{sub 2}). We investigated the correlation between the catalyst's Ce valence state and its activity. Different Ce{sup 3+} ratios were observed when various metals were added to Ce/Ti. The highest Ce{sup 3+} ratio was observed in 10Ce/W/Ti at 0.3027, and the catalyst efficiency had a positive correlation with higher Ce{sup 3+} ratios. The SCR activity was found to increase as the Ce{sup 3+} ratio increased when tungsten was added to 10Ce/W/Ti. Furthermore, in the case of 10Ce/W/Ti, it seemed that the Brønsted acid sites were more abundant relative to those on 10Ce/Ti. Upon the injection of SO{sub 2} in the SCR reaction, 10Ce/Ti was rapidly deactivated. However, the 10Ce

  14. Fe-Containing Zeolites for NH3-SCR of NOx: Effect of Structure, Synthesis Procedure, and Chemical Composition on Catalytic Performance and Stability.

    Science.gov (United States)

    Martín, Nuria; Vennestrøm, Peter N R; Thøgersen, Joakim R; Moliner, Manuel; Corma, Avelino

    2017-09-27

    The direct preparation of different iron-containing Beta and CHA zeolites has been attempted under diverse synthesis conditions, including in alkaline and fluoride media, to evaluate the influence of their physicochemical properties on the selective catalytic reduction (SCR) of NO x using NH 3 as reductant. Of the different Fe-Beta zeolites, the sample prepared in the absence of alkali cations with a Si/Al ratio of around 13 showed high NO conversion values (>90 %). However, this catalyst suffered from severe deactivation when aged at high temperatures in the presence of steam. The preparation of more hydrophobic Fe-Beta zeolites did not improve the resistance of the catalyst against steam. In contrast, Fe-CHA zeolites prepared by a one-pot method under alkaline conditions with a Si/Al ratio of around 13 by using N,N,N-trimethyladamantylammonium as template not only showed excellent catalytic activity but also high hydrothermal stability, especially when sodium cations were selectively removed. Moreover, the Fe-CHA material synthesized by using the less expensive tetraethylammonium template also resulted in an active and hydrothermally stable catalyst. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Detailed modelling of processes inside a catalytic recombiner for hydrogen removal

    International Nuclear Information System (INIS)

    Heitsch, M.

    1999-01-01

    Under accidental conditions, considerable amounts of hydrogen may be released into the containment. Catalytic reacting surfaces in recombiners are a reliable method to recombine this hydrogen and other burnable gases like carbon monoxide from the atmosphere in a passive way. Many experiments have been carried out to study the main phenomena occurring inside recombiners, like the efficiency of hydrogen removal, the start-up conditions, poisoning, oxygen starvation, steam and water impact, and others. In addition, the global behavior of a given recombiner device in a larger environment has been investigated in order to demonstrate the effectiveness and to facilitate the derivation of simplified models for long term, severe accident analyses. These long-term severe accident models are complemented by detailed investigations to understand the interaction of chemistry and flow inside a recombiner box. This helps to provide the dependencies of non-measurable variables (e.g. the reaction rate distribution), of local surface temperatures etc. to make long-term or system models more reliable. It also offers possibilities for increasing the chemical efficiency by optimising the geometric design properly. Computational Fluid Dynamics (CFD) codes are available for use as development tools to include the specifics of catalytic surface reactors. The present paper describes the use of the code system CFX [1] for creating a recombiner model. Some model predictions are compared to existing test data. (author)

  16. Modeling of adsorber/desorber/catalytic reactor system for ethylene oxide removal

    Directory of Open Access Journals (Sweden)

    ZELJKO B. GRBAVCIC

    2004-12-01

    Full Text Available The removal of ethylene oxide (EtO in a combined system adsorber/desorber/catalytic reactor has been investigated. The combined system was a modified draft tube spouted bed reactor loaded with Pt/Al2O3 catalyst. The annular region was divided into two sectons, the “hot” section contained about 7 % of catalyst and it behaved as a desorber and catalytic incinerator, while the “cold” section, with the rest of the catalyst, behaved as a sorber. The catalyst particles were circulated between the two sections by use of a draft tube riser. The Computational Fluid Dynamics (CFD program package FLUENT was used for simulations of the operation of the combined system. In addition, a one-dimensional numerical model for the operation of the packed bed reactor was compared with the corresponding FLUENT calculations. The results of the FLUENT simulations are in very good agreement with the experimental observations, as well as with the results of the one-dimensional numerical simulations.

  17. Improvement of LSM15-CGO10 electrodes for electrochemical removal of NOx by KNO3 and MnOx impregnation

    DEFF Research Database (Denmark)

    Traulsen, Marie Lund; Kammer Hansen, Kent

    2011-01-01

    in 1000 ppm NO, 10% O2 and 1000 ppm NO + 10% O2 in the temperature range 300-500 °C and the electrodes were investigated by scanning electron microscopy before and after testing. At 400-450 °C a NOx-storage process was observed on the KNO3-impregnated electrodes, this process appeared to be dependent...

  18. Effects of a catalytic volatile particle remover (VPR) on the particulate matter emissions from a direct injection spark ignition engine.

    Science.gov (United States)

    Xu, Fan; Chen, Longfei; Stone, Richard

    2011-10-15

    Emissions of fine particles have been shown to have a large impact on the atmospheric environment and human health. Researchers have shown that gasoline engines, especially direct injection spark ignition (DISI) engines, tend to emit large amounts of small size particles compared to diesel engines fitted with diesel particulate filters (DPFs). As a result, the particle number emissions of DISI engines will be restricted by the forthcoming EU6 legislation. The particulate emission level of DISI engines means that they could face some challenges in meeting the EU6 requirement. This paper is an experimental study on the size-resolved particle number emissions from a spray guided DISI engine and the performance of a catalytic volatile particle remover (VPR), as the EU legislation seeks to exclude volatile particles. The performance of the catalytic VPR was evaluated by varying its temperature and the exhaust residence time. The effect of the catalytic VPR acting as an oxidation catalyst on particle emissions was also tested. The results show that the catalytic VPR led to a marked reduction in the number of particles, especially the smaller size (nucleation mode) particles. The catalytic VPR is essentially an oxidation catalyst, and when post three-way catalyst (TWC) exhaust was introduced to the catalytic VPR, the performance of the catalytic VPR was not affected much by the use of additional air, i.e., no significant oxidation of the PM was observed.

  19. DeNOx study in diesel engine exhaust using barrier discharge corona assisted by V2O5/TiO2 catalyst

    International Nuclear Information System (INIS)

    Rajanikanth, B.S.; Ravi, V.

    2004-01-01

    A plasma-assisted catalytic reactor was used to remove nitrogen oxides (NOx) from diesel engine exhaust operated under different load conditions. Initial studies were focused on plasma reactor (a dielectric barrier discharge reactor) treatment of diesel exhaust at various temperatures. The nitric oxide (NO) removal efficiency was lowered when high temperature exhaust was treated using plasma reactor. Also, NO removal efficiency decreased when 45% load exhaust was treated. Studies were then made with plasma reactor combined with a catalytic reactor consisting of a selective catalytic reduction (SCR) catalyst, V 2 O 5 /TiO 2 . Ammonia was used as a reducing agent for SCR process in a ratio of 1:1 to NOx. The studies were focused on temperatures of the SCR catalytic reactor below 200 degree C. The plasma-assisted catalytic reactor was operated well to remove NOx under no-load and load conditions. For an energy input of 96 J/1, the NOx removal efficiencies obtained under no-load and load conditions were 90% and 72% respectively at an exhaust temperature of 100 degree C. (authors)

  20. Final Technical Report on Investigation of Selective Non-Catalytic Processes for In-Situ Reduction of NOx and CO Emissions from Marine Gas Turbines and Diesel Engines

    National Research Council Canada - National Science Library

    Bowman, Craig

    1997-01-01

    .... These observations suggest the possibility of utilizing SNCR for reducing NO(x) emissions from marine gas turbines and Diesel engines by direct injection of a reductant species into the combustion chamber, possibly as a fuel...

  1. Removal of radionuclides from partitioning waste solutions by adsorption and catalytic oxidation methods

    Energy Technology Data Exchange (ETDEWEB)

    Yamagishi, Isao; Yamaguchi, Isoo [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Kubota, Masumitsu [Research Organization for Information Science and Technology (RIST), Tokai, Ibaraki (Japan)

    2000-09-01

    Adsorption of radionuclides with inorganic ion exchangers and catalytic oxidation of a complexant were studied for the decontamination of waste solutions generated in past partitioning tests with high-level liquid waste. Granulated ferrocyanide and titanic acid were used for adsorption of Cs and Sr, respectively, from an alkaline solution resulting from direct neutralization of an acidic waste solution. Both Na and Ba inhibited adsorption of Sr but Na did not that of Cs. These exchangers adsorbed Cs and Sr at low concentration with distribution coefficients of more than 10{sup 4}ml/g from 2M Na solution of pH11. Overall decontamination factors (DFs) of Cs and total {beta} nuclides exceeded 10{sup 5} and 10{sup 3}, respectively, at the neutralization-adsorption step of actual waste solutions free from a complexant. The DF of total {alpha} nuclides was less than 10{sup 3} for a waste solution containing diethylenetriaminepentaacetic acid (DTPA). DTPA was rapidly oxidized by nitric acid in the presence of a platinum catalyst, and radionuclides were removed as precipitates by neutralization of the resultant solution. The DF of {alpha} nuclides increased to 8x10{sup 4} by addition of the oxidation step. The DFs of Sb and Co were quite low through the adsorption step. A synthesized Ti-base exchanger (PTC) could remove Sb with the DF of more than 4x10{sup 3}. (author)

  2. ACIDIC REMOVAL OF METALS FROM FLUIDIZED CATALYTIC CRACKING CATALYST WASTE ASSISTED BY ELECTROKINETIC TREATMENT

    Directory of Open Access Journals (Sweden)

    R. B. G. Valt

    2015-06-01

    Full Text Available AbstractOne of the main uses of catalysts in the oil industry is in the fluidized catalytic cracking process, which generates large quantities of waste material after use and regeneration cycles and that can be treated by the electrokinetic remediation technique, in which the contaminant metals are transported by migration. In this study, deactivated FCC catalyst was characterized before and after the electrokinetic remediation process to evaluate the amount of metal removed, and assess structural modifications, in order to indicate a possible use as an adsorbent material. The analyses included pH measurement and the concentration profile of vanadium ions along the reactor, X-ray microtomography, X-ray fluorescence, BET analysis and DTA analysis. The results indicated that 40% of the surface area of the material was recovered in relation to the disabled material, showing an increase in the available area for the adsorption. The remediation process removed nearly 31% of the vanadium and 72% of the P2O5 adhering to the surface of the catalyst, without causing structural or thermal stability changes.

  3. Ammonia-Free NOx Control System

    Energy Technology Data Exchange (ETDEWEB)

    Song Wu; Zhen Fan; Andrew H. Seltzer; Richard G. Herman

    2005-03-31

    Research is being conducted under United States Department of Energy (DOE) Contract DE-FC26-03NT41865 to develop a new technology to achieve very low levels of NOx emissions from pulverized coal fired boiler systems by employing a novel system level integration between the PC combustion process and the catalytic NOx reduction with CO present in the combustion flue gas. The combustor design and operating conditions will be optimized to achieve atypical flue gas conditions. This approach will not only suppress NOx generation during combustion but also further reduce NOx over a downstream catalytic reactor that does not require addition of an external reductant, such as ammonia.

  4. Ammonia-Free NOx Control System

    Energy Technology Data Exchange (ETDEWEB)

    Song Wu; Zhen Fan; Andrew H. Seltzer

    2005-06-30

    Research is being conducted under United States Department of Energy (DOE) Contract DEFC26-03NT41865 to develop a new technology to achieve very low levels of NOx emissions from pulverized coal fired boiler systems by employing a novel system level integration between the PC combustion process and the catalytic NOx reduction with CO present in the combustion flue gas. The combustor design and operating conditions will be optimized to achieve atypical flue gas conditions. This approach will not only suppress NOx generation during combustion but also further reduce NOx over a downstream catalytic reactor that does not require addition of an external reductant, such as ammonia.

  5. Removal of Selected Heavy Metals from Green Mussel via Catalytic Oxidation

    International Nuclear Information System (INIS)

    Faizuan Abdullah; Abdull Rahim Mohd Yusoff; Wan Azelee Wan Abu Bakar; Razali Ismail; Dwi Priya Hadiyanto

    2014-01-01

    Perna viridis or green mussel is a potentially an important aquaculture product along the South Coast of Peninsular Malaysia especially Johor Straits. As the coastal population increases at tremendous rate, there was significant effect of land use changes on marine communities especially green mussel, as the heavy metals input to the coastal area also increase because of anthropogenic activities. Heavy metals content in the green mussel exceeded the Malaysian Food Regulations (1985) and EU Food Regulations (EC No: 1881/ 2006). Sampling was done at Johor Straits from Danga to Pendas coastal area for green mussel samples. This research introduces a catalytic oxidative technique for demetallisation in green mussel using edible oxidants such as peracetic acid (PAA) enhanced with alumina beads supported CuO, Fe 2 O 3 , and ZnO catalysts. The lethal dose of LD 50 to rats of PAA is 1540 mg kg -1 was verified by National Institute of Safety and Health, United State of America. The best calcination temperature for the catalysts was at 1000 degree Celsius as shown in the X-Ray Diffraction (XRD), Nitrogen Adsorption (BET surface area) and Field Emission Scanning Electron Microscopy (FESEM) analyses. The demetallisation process in green mussel was done successfully using only 100 mgL -1 PAA and catalyzed with Fe 2 O 3 / Al 2 O 3 for up to 90 % mercury (Hg) removal. Using PAA with only 1 hour of reaction time, at room temperature (30-35 degree Celsius), pH 5-6 and salinity of 25-28 ppt, 90 % lead (Pb) was removed from life mussel without catalyst. These findings have a great prospect for developing an efficient and practical method for post-harvesting heavy metals removal in green mussel. (author)

  6. Enhancement of NOx removal performance for (La0.85Sr0.15)0.99MnO3/Ce0.9Gd0.1O1.95 electrochemical cells by NOx storage/reduction adsorption layers

    DEFF Research Database (Denmark)

    Shao, Jing; Kammer Hansen, Kent

    2013-01-01

    This study investigated the effect of adding a NOx adsorption layer to the cathode of an electrochemical cell on the removal of NOx from gaseous mixtures. The cathode was a composite of (La0.85Sr0.15)0.99MnO3 (LSM15) and Ce0.9Gd0.1O1.95 (CGO10). Two different kinds of adsorption layers, K–Pt–Al2O...... reaction path for NOx reduction. A stronger capability for oxidizing NO and/or trapping NOx under the test conditions may have contributed to the superior performance of the K–Pt–Al2O3 adsorption layer relative to the Ba–Pt–Al2O3 layer. © 2012 Elsevier Ltd. All rights reserved....

  7. Removal of nitrogen compounds from gasification gas by selective catalytic or non-catalytic oxidation; Typpiyhdisteiden poisto kaasutuskaasusta selektiivisellae katalyyttisellae ja ei-katalyyttisellae hapetuksella

    Energy Technology Data Exchange (ETDEWEB)

    Leppaelahti, J.; Koljonen, T. [VTT Energy, Espoo (Finland)

    1996-12-01

    In gasification reactive nitrogenous compounds are formed from fuel nitrogen, which may form nitrogen oxides in gas combustion. In fluidized bed gasification the most important nitrogenous compound is ammonia (NH{sub 3}). If ammonia could be decomposed to N{sub 2} already before combustion, the emissions if nitrogen oxides could be reduced significantly. One way of increasing the decomposition rate of NH{sub 3} could be the addition of suitable reactants to the gas, which would react with NH{sub 3} and produce N{sub 2}. The aim of this research is to create basic information, which can be used to develop a new method for removal of nitrogen compounds from gasification gas. The reactions of nitrogen compounds and added reactants are studied in reductive atmosphere in order to find conditions, in which nitrogen compounds can be oxidized selectively to N{sub 2}. The project consists of following subtasks: (1) Selective non-catalytic oxidation (SNCO): Reactions of nitrogen compounds and oxidizers in the gas phase, (2) Selective catalytic oxidation (SCO): Reactions of nitrogen compounds and oxidizers on catalytically active surfaces, (3) Kinetic modelling of experimental results in co-operation with the Combustion Chemistry Research Group of Aabo Akademi University. The most important finding has been that NH{sub 3} can be made to react selectively with the oxidizers even in the presence of large amounts of CO and H{sub 2}. Aluminium oxides were found to be the most effective materials promoting selectivity. (author)

  8. Removal of formaldehyde over Mn(x)Ce(1)-(x)O(2) catalysts: thermal catalytic oxidation versus ozone catalytic oxidation.

    Science.gov (United States)

    Li, Jia Wei; Pan, Kuan Lun; Yu, Sheng Jen; Yan, Shaw Yi; Chang, Moo Been

    2014-12-01

    Mn(x)Ce(1)-(x)O(2) (x: 0.3-0.9) prepared by Pechini method was used as a catalyst for the thermal catalytic oxidation of formaldehyde (HCHO). At x=0.3 and 0.5, most of the manganese was incorporated in the fluorite structure of CeO(2) to form a solid solution. The catalytic activity was best at x=0.5, at which the temperature of 100% removal rate is the lowest (270°C). The temperature for 100% removal of HCHO oxidation is reduced by approximately 40°C by loading 5wt.% CuO(x) into Mn(0.5)Ce(0.5)O(2). With ozone catalytic oxidation, HCHO (61 ppm) in gas stream was completely oxidized by adding 506 ppm O₃over Mn(0.5)Ce(0.5)O(2) catalyst with a GHSV (gas hourly space velocity) of 10,000 hr⁻¹ at 25°C. The effect of the molar ratio of O(3) to HCHO was also investigated. As O(3)/HCHO ratio was increased from 3 to 8, the removal efficiency of HCHO was increased from 83.3% to 100%. With O(3)/HCHO ratio of 8, the mineralization efficiency of HCHO to CO(2) was 86.1%. At 25°C, the p-type oxide semiconductor (Mn(0.5)Ce(0.5)O(2)) exhibited an excellent ozone decomposition efficiency of 99.2%, which significantly exceeded that of n-type oxide semiconductors such as TiO(2), which had a low ozone decomposition efficiency (9.81%). At a GHSV of 10,000 hr⁻¹, [O(3)]/[HCHO]=3 and temperature of 25°C, a high HCHO removal efficiency (≥ 81.2%) was maintained throughout the durability test of 80 hr, indicating the long-term stability of the catalyst for HCHO removal. Copyright © 2014. Published by Elsevier B.V.

  9. Remarkably enhanced density and specific activity of active sites in Al-rich Cu-, Fe- and Co-beta zeolites for selective catalytic reduction of NOx

    Czech Academy of Sciences Publication Activity Database

    Sazama, Petr; Pilař, Radim; Mokrzycki, Lukasz; Vondrová, Alena; Kaucký, Dalibor; Plšek, Jan; Sklenák, Štěpán; Šťastný, Petr; Klein, Petr

    2016-01-01

    Roč. 189, JUL 2016 (2016), s. 65-74 ISSN 0926-3373 R&D Projects: GA TA ČR(CZ) TH01021259 Institutional support: RVO:61388955 Keywords : SCR- NOx * Al-rich beta zeolite (*BEA) * Cobalt Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 9.446, year: 2016

  10. Remarkably enhanced density and specific activity of active sites in Al-rich Cu-, Fe- and Co-beta zeolites for selective catalytic reduction of NOx

    Czech Academy of Sciences Publication Activity Database

    Sazama, Petr; Pilař, Radim; Mokrzycki, Lukasz; Vondrová, Alena; Kaucký, Dalibor; Plšek, Jan; Sklenák, Štěpán; Šťastný, Petr; Klein, Petr

    2016-01-01

    Roč. 189, JUL 2016 (2016), s. 65-74 ISSN 0926-3373 R&D Projects: GA TA ČR(CZ) TH01021259 Institutional support: RVO:61388955 Keywords : SCR-NOx * Al-rich beta zeolite (*BEA) * Cobalt Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 9.446, year: 2016

  11. Structural Analysis of Potential Active Sites in Metallo-zeolites for Selective Catalytic Reduction of NOx. An Attempt for the Structure versus Activity Relatioship

    Czech Academy of Sciences Publication Activity Database

    Wichterlová, Blanka

    2004-01-01

    Roč. 28, 1/4 (2004), s. 131-140 ISSN 1022-5528 R&D Projects: GA MŠk 1P04OCD15.20 Institutional research plan: CEZ:AV0Z4040901 Keywords : SCR-NOx * Co-zeolites * Fe-zeolites Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.493, year: 2004

  12. An Evaluation of the Vapor Phase Catalytic Ammonia Removal Process for Use in a Mars Transit Vehicle

    Science.gov (United States)

    Flynn, Michael; Borchers, Bruce

    1998-01-01

    An experimental program has been developed to evaluate the potential of the Vapor Phase Catalytic Ammonia Reduction (VPCAR) technology for use as a Mars Transit Vehicle water purification system. Design modifications which will be required to ensure proper operation of the VPCAR system in reduced gravity are also evaluated. The VPCAR system is an integrated wastewater treatment technology that combines a distillation process with high temperature catalytic oxidation. The distillation portion of the system utilizes a vapor compression distillation process to provide an energy efficient phase change separation. This portion of the system removes any inorganic salts and large molecular weight, organic contaminates, i.e., non-volatile, from the product water stream and concentrates these contaminates into a byproduct stream. To oxidize the volatile organic compounds and ammonia, a vapor phase, high temperature catalytic oxidizer is used. This catalytic system converts these compounds along with the aqueous product into CO2, H2O, and N2O. A secondary catalytic bed can then be used to reduce the N2O to nitrogen and oxygen (although not evaluated in this study). This paper describes the design specification of the VPCAR process, the relative benefits of its utilization in a Mars Transit Vehicle, and the design modification which will be required to ensure its proper operation in reduced gravity. In addition, the results of an experimental evaluation of the processors is presented. This evaluation presents the processors performance based upon product water purity, water recovery rates, and power.

  13. Nox NADPH oxidases and the endoplasmic reticulum.

    Science.gov (United States)

    Laurindo, Francisco R M; Araujo, Thaís L S; Abrahão, Thalita B

    2014-06-10

    Understanding isoform- and context-specific subcellular Nox reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidase compartmentalization allows relevant functional inferences. This review addresses the interplay between Nox NADPH oxidases and the endoplasmic reticulum (ER), an increasingly evident player in redox pathophysiology given its role in redox protein folding and stress responses. Catalytic/regulatory transmembrane subunits are synthesized in the ER and their processing includes folding, N-glycosylation, heme insertion, p22phox heterodimerization, as shown for phagocyte Nox2. Dual oxidase (Duox) maturation also involves the regulation by ER-resident Duoxa2. The ER is the activation site for some isoforms, typically Nox4, but potentially other isoforms. Such location influences redox/Nox-mediated calcium signaling regulation via ER targets, such as sarcoendoplasmic reticulum calcium ATPase (SERCA). Growing evidence suggests that Noxes are integral signaling elements of the unfolded protein response during ER stress, with Nox4 playing a dual prosurvival/proapoptotic role in this setting, whereas Nox2 enhances proapoptotic signaling. ER chaperones such as protein disulfide isomerase (PDI) closely interact with Noxes. PDI supports growth factor-dependent Nox1 activation and mRNA expression, as well as migration in smooth muscle cells, and PDI overexpression induces acute spontaneous Nox activation. Mechanisms of PDI effects include possible support of complex formation and RhoGTPase activation. In phagocytes, PDI supports phagocytosis, Nox activation, and redox-dependent interactions with p47phox. Together, the results implicate PDI as possible Nox organizer. We propose that convergence between Noxes and ER may have evolutive roots given ER-related functional contexts, which paved Nox evolution, namely calcium signaling and pathogen killing. Overall, the interplay between Noxes and the ER may provide relevant insights in Nox-related (patho)physiology.

  14. Removal of Humic Substances from Water by Advanced Oxidation Process Using UV/TiO2 Photo Catalytic Technology

    Directory of Open Access Journals (Sweden)

    Hassan Khorsandi

    2009-01-01

    Full Text Available Humic substances have been known as precursors to disinfection by-products. Because conventional treatment processes cannot meet disinfection by-product standards, novel methods have been increasingly applied for the removal of disinfection by-products precursors. The UV/TiO2 process is one of the advanced oxidation processes using the photocatalytic technology. The most important advantages of this process are its stability and high efficiency removal. The present study aims to investigate the effect of UV/TiO2 photo-catalytic technology on removal of humic substances. The study was conducted in a lab-scale batch photo-catalytic reactor using the interval experimental method. The UV irradiation source was a low pressure mercury vapor lamp 55w that was axially centered and was immersed in a humic acids solution within a stainless steel tubular 2.8 L reaction volume. Each of the samples taken from the UV/TiO2 process and other processes studied were analyzed for their dissolved organic carbon, UV absorbance at 254nm, and specific UV254 absorbance. The results indicated the high efficiency of the UV/TiO2 photo-catalytic process (TiO2=0.1 g/L and pH=5, compared to other processes, for humic substances removal from water sources. The process was also found to be capable of decreasing the initial dissolved organic carbon from 5 to 0.394 mg/L. The Specific UV254 Absorbance of 2.79 L/mg.m was attained after 1.5 hr. under photo-catalytic first order reaction (k= 0.0267 min-1. It may be concluded that the UV/TiO2 process can provide desirable drinking water quality in terms of humic substance content.

  15. Photo Catalytic Removal of Sodium Dodecyl Sulfate From Aquatic Solutions With Prepared ZnO Nanocrystals and UV Irradiation

    Directory of Open Access Journals (Sweden)

    Mohammad Taghi Samadi

    2014-12-01

    Full Text Available In this study, ZnO Nano catalyst has been synthesized and examined as photo catalyst for UV-induced removal of Sodium Dodecyl Sulfate (SDS from aquatic solutions. This anionic surfactant was selected based upon its toxicity, wide use in industrial laundry and as a primary pollutant in municipal waste water systems.This study aimed to investigate removal of surfactant, SDS, in a batch photo catalytic reactor under various operating conditions including ZnO suspension concentration, initial surfactant concentration and initial pH of solution to find out the desired condition for removal of surfactant. ZnO Nano crystals were synthesized using the precipitation method and ZnSO4.7H2O was used as the starting material and NaOH as precipitant. The removal of SDS reactions by UV/ZnO process was performed into a batch photo reactor. In addition, various operating conditions including ZnO suspension concentration, initial surfactant concentration and initial pH of solution were investigated. In total, 98% of surfactant was removed at 40 minute and removal efficiency of SDS increased with increasing pH up to nine and after that with increase in pH, efficiency decreased. Possible roles of inorganic oxidant on the reaction were discussed. The removal of SDS follows pseudo-first order kinetics. Based on the results of this study, ZnO-UV photo catalytic process can be used as an efficient method for further study in detergents removal.

  16. Modeling and simulation of ammonia removal from purge gases of ammonia plants using a catalytic Pd-Ag membrane reactor

    International Nuclear Information System (INIS)

    Rahimpour, M.R.; Asgari, A.

    2008-01-01

    In this work, the removal of ammonia from synthesis purge gas of an ammonia plant has been investigated. Since the ammonia decomposition is thermodynamically limited, a membrane reactor is used for complete decomposition. A double pipe catalytic membrane reactor is used to remove ammonia from purge gas. The purge gas is flowing in the reaction side and is converted to hydrogen and nitrogen over nickel-alumina catalyst. The hydrogen is transferred through the Pd-Ag membrane of tube side to the shell side. A mathematical model including conservation of mass in the tube and shell side of reactor is proposed. The proposed model was solved numerically and the effects of different parameters on the rector performance were investigated. The effects of pressure, temperature, flow rate (sweep ratio), membrane thickness and reactor diameter have been investigated in the present study. Increasing ammonia conversion was observed by raising the temperature, sweep ratio and reducing membrane thickness. When the pressure increases, the decomposition is gone toward completion but, at low pressure the ammonia conversion in the outset of reactor is higher than other pressures, but complete destruction of the ammonia cannot be achieved. The proposed model can be used for design of an industrial catalytic membrane reactor for removal of ammonia from ammonia plant and reducing NO x emissions

  17. Gas cleaning and hydrogen sulfide removal for COREX coal gas by sorption enhanced catalytic oxidation over recyclable activated carbon desulfurizer.

    Science.gov (United States)

    Sun, Tonghua; Shen, Yafei; Jia, Jinping

    2014-02-18

    This paper proposes a novel self-developed JTS-01 desulfurizer and JZC-80 alkaline adsorbent for H2S removal and gas cleaning of the COREX coal gas in small-scale and commercial desulfurizing devices. JTS-01 desulfurizer was loaded with metal oxide (i.e., ferric oxides) catalysts on the surface of activated carbons (AC), and the catalyst capacity was improved dramatically by means of ultrasonically assisted impregnation. Consequently, the sulfur saturation capacity and sulfur capacity breakthrough increased by 30.3% and 27.9%, respectively. The whole desulfurizing process combined selective adsorption with catalytic oxidation. Moreover, JZC-80 adsorbent can effectively remove impurities such as HCl, HF, HCN, and ash in the COREX coal gas, stabilizing the system pressure drop. The JTS-01 desulfurizer and JZC-80 adsorbent have been successfully applied for the COREX coal gas cleaning in the commercial plant at Baosteel, Shanghai. The sulfur capacity of JTS-01 desulfurizer can reach more than 50% in industrial applications. Compared with the conventional dry desulfurization process, the modified AC desulfurizers have more merit, especially in terms of the JTS-01 desulfurizer with higher sulfur capacity and low pressure drop. Thus, this sorption enhanced catalytic desulfurization has promising prospects for H2S removal and other gas cleaning.

  18. Tritium removal from air streams by catalytic oxidation and water adsorption

    International Nuclear Information System (INIS)

    Sherwood, A.E.

    1976-06-01

    An effective method of capturing tritium from air streams is by catalytic oxidation followed by water adsorption on a microporous solid adsorbent. Performance of a burner/dryer combination is illustrated by overall mass balance equations. Engineering design methods for packed bed reactors and adsorbers are reviewed, emphasizing the experimental data needed for design and the effect of operating conditions on system performance

  19. NOx and PAHs removal from industrial flue gas by using electron beam technology in the alcohol addition

    International Nuclear Information System (INIS)

    Sun, Y.X.; Chmielewski, A.G.; Bulka, S.; Zimek, Z.; Licki, J.; Kubica, K.

    2002-01-01

    Complete text of publication follows. The preliminary test of NO x and Polycyclic Aromatic Hydrocarbons (PAHs) removal from flue gas were investigated in the alcohol addition by using electron beam irradiation in EPS Kaweczyn. Experimental conditions were as follows: flue gas flow rate 5000 nM 3 /hr; humidity 4-5%; inlet concentrations of SO 2 and NO x , which were emitted from power station, were 192 ppm and 106 ppm, respectively; ammonia addition is 2.75 m 3 /hr; alcohol addition is 600 l/hr. It was found that NO x removal efficiency in the presence of alcohol was increased by 10% than without alcohol addition when the absorbed dose was below 6 kGy. The NO x removal efficiency was decreased when the absorbed dose was higher than 10 kGy. In order to understand PAHs' behavior under EB irradiation, inlet PAHs (emitted from coal combustion process) sample and outlet PAHs (after irradiation) sample were collected by using a condensed bottle connected with XAD-2 adsorbent and active carbon adsorbent and were analyzed by a GC-MS. It is found that: at the 8 kGy adsorbed dose, concentrations of PAHs with small aromatic rings (≤3, except Acenaphthylene) are reduced and concentrations of PAHs with large aromatic rings (≤4) are increased. A possible mechanism is proposed

  20. Intake condition requirements for biodiesel modulated kinetic combustion concept to achieve a simultaneous NOx and soot removal

    International Nuclear Information System (INIS)

    Kim, Keunsoo; Oh, Seungmook; Lee, Yonggyu; Lee, Sunyoup; Kim, Junghwan

    2015-01-01

    Highlights: • MK LTC combustion was investigated under various intake conditions. • BD20 MK combustion achieved NO x and soot removal at achievable intake conditions. • The BD20 best point showed lower ISFC and COV IMEP than the diesel best point. • Higher intake pressure showed higher efficiency at all intake oxygen concentrations. • Simultaneous NO x and soot removal required 200 kPa intake pressure at a medium load. - Abstract: The fuel oxygen contained in oxygenated fuels can help reduce harmful engine-out emissions and improve the combustion process in compression-ignition engines. The use of soybean methylene ether biodiesel in the low-temperature combustion (LTC) regime has the potential to suppress soot formation and nitrogen oxides (NO x ) emissions even further, which eventually alleviates the burden of the after-treatment system. In the present study, the effects of the intake pressure and injection timing on the combustion and emissions of the modulated kinetic (MK) combustion concept with ultra-low sulfur diesel and 20% biodiesel blended fuel (BD20) were investigated in a single-cylinder CI engine. The intake pressure was varied from 100 kPa to 250 kPa for the intake oxygen concentration range of 11–17%. The engine test results indicate that simultaneous reductions in both the NO x and soot emissions were realized under the MK LTC combustion regime. At the best operating point, BD20 achieved the simultaneous NO x and soot removal at a lower intake pressure and lower EGR level than diesel, which led to better fuel economy. In addition, BD20 achieved acceptable levels of combustion stability and noise level

  1. A Broad Spectrum Catalytic System for Removal of Toxic Organics from Water by Deep Oxidation - Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Sen, Ayusman

    2000-12-01

    A most pressing need for the DOE environmental management program is the removal of toxic organic compounds present in groundwater and soil at specific DOE sites. While several remediation procedures have been proposed, they suffer from one or more drawbacks. The objective of the present research was to develop new catalytic procedures for the removal of toxic organic compounds from the environment through their deep oxidation to harmless products. In water, metallic palladium was found to catalyze the deep oxidation of a wide variety of toxic organic compounds by dioxygen at 80-90 C in the presence of carbon monoxide or dihydrogen. Several classes of organic compounds were examined: benzene, phenol and substituted phenols, nitro and halo organics, organophosphorus, and organosulfur compounds. In every case, deep oxidation to carbon monoxide, carbon dioxide, and water occurred in high yields, resulting in up to several hundred turnovers over a 24 hour period. For substrates susceptible to hydrogenation, the conversions were generally high with dihydrogen than with carbon monoxide. It is clear from the results obtained that we have discovered an exceptionally versatile catalytic system for the deep oxidation of toxic organic compounds in water. This system possesses several attractive features not found simultaneously in other reported systems. These are (a) the ability to directly utilize dioxygen as the oxidant, (b) the ability to carry out the deep oxidation of a particularly wide range of functional organics, and (c) the ease of recovery of the catalyst by simple filtration.

  2. Nitrogen Isotope Composition of Thermally Produced NOx from Various Fossil-Fuel Combustion Sources.

    Science.gov (United States)

    Walters, Wendell W; Tharp, Bruce D; Fang, Huan; Kozak, Brian J; Michalski, Greg

    2015-10-06

    The nitrogen stable isotope composition of NOx (δ(15)N-NOx) may be a useful indicator for NOx source partitioning, which would help constrain NOx source contributions in nitrogen deposition studies. However, there is large uncertainty in the δ(15)N-NOx values for anthropogenic sources other than on-road vehicles and coal-fired energy generating units. To this end, this study presents a broad analysis of δ(15)N-NOx from several fossil-fuel combustion sources that includes: airplanes, gasoline-powered vehicles not equipped with a three-way catalytic converter, lawn equipment, utility vehicles, urban buses, semitrucks, residential gas furnaces, and natural-gas-fired power plants. A relatively large range of δ(15)N-NOx values was measured from -28.1‰ to 8.5‰ for individual exhaust/flue samples that generally tended to be negative due to the kinetic isotope effect associated with thermal NOx production. A negative correlation between NOx concentrations and δ(15)N-NOx for fossil-fuel combustion sources equipped with selective catalytic reducers was observed, suggesting that the catalytic reduction of NOx increases δ(15)N-NOx values relative to the NOx produced through fossil-fuel combustion processes. Combining the δ(15)N-NOx measured in this study with previous published values, a δ(15)N-NOx regional and seasonal isoscape was constructed for the contiguous U.S., which demonstrates seasonal and regional importance of various NOx sources.

  3. Effect of CaO on NOx Reduction by Selective Non-Catalytic Reduction under Variable Gas Compositions in a Simulated Cement Precalciner Atmosphere.

    Science.gov (United States)

    Sun, Ye; Fan, Weiyi; Zhu, Tianle; Hong, Xiaowei

    2017-11-29

    High-concentration CaO particles and gas compositions have a significant influence on NO x reduction by selective non-catalytic reduction (SNCR) in cement precalciners. The effect of gas composition on NO x reduction by SNCR with NH₃ was studied in a cement precalciner atmosphere with and without CaO at 700-1100 °C. It was found that CaO significantly lowers NO x reduction efficiency between 750 °C and 1000 °C, which is attributed to the catalytic oxidation of NH₃ to NO. Although increasing NH₃ concentration was advantageous to NO x reduction, the existence of CaO led to the opposite result at 750-900 °C. Adding H₂O can suppress the negative effect of CaO on NO x reduction. Decreasing O₂ content from 10% to 1% shifts the temperature range in which CaO has a significant effect from 750-1000 °C to 800-1050 °C. CO has a variety of influences on the CaO effect under different experimental conditions. The influences of NH₃, H₂O, O₂, and CO on the effect of CaO can be attributed to the impacts of the gas compositions on gas-phase NH₃ conversion, gas-solid catalytic NH₃ oxidation, or both processes. A proposed pathway for the effect of gas compositions on NO x reduction in CaO-containing SNCR process was developed that well predicted the CaO-containing SNCR process.

  4. Investigating the effect of gas flow rate, inlet ozone concentration and relative humidity on the efficacy of catalytic ozonation process in the removal of xylene from waste airstream

    Directory of Open Access Journals (Sweden)

    H.R. MokaramI

    2010-10-01

    Full Text Available Background and aimsThe catalytic ozonation is an efficient process for the degradation of volatile organic compounds from contaminated air stream. This study was aimed at investigating the efficacy of catalytic ozonation process in removal of xylene from the polluted air stream andthe influence of retention time (gas flow rate, inlet ozone dose and relative humidity on this performanceMethodsthe catalytic ozonation of xylene was conducted using a bench scale set-up consisted of a syringe pump,an air pump, an ozone generator, and a glass reactor packed with activated carbon. Several experimental run was defined to investigate the influence of the selectedoperational variables.ResultsThe results indicated that the efficiency of catalytic ozonation was greater than that of single adsorption in removal of xylene under similar inlet concentration and relative humidity. We found a significant catalytic effect for activated carbon when used in combination with ozonation process, leading to improvement of xylene removal percentage. In addition, the elimination capacity of the system improved with the increase of inlet ozone dose as well as gas flow rate. The relative humidity showed a positive effect of the xylene removal at the range of 5 to 50%, while the higher humidity (more than 50% resulted in reduction of the performance.ConclusionThe findings of the present work revealed that the catalytic ozonation process can be an efficient technique for treating the air streams containing industrial concentrations of xylene. Furthermore, there is a practical potential to retrofit the present adsorption systems intothe catalytic ozonation simply by coupling them with the ozonation system. the catalytic ozonation of xylene was conducted using a bench scale set-up consisted of a syringe pump,an air pump, an ozone generator, and a glass reactor packed with activated carbon. Several experimental run was defined to investigate the influence of the selected

  5. Ammonia-Free NOx Control System

    Energy Technology Data Exchange (ETDEWEB)

    Song Wu; Zhen Fan; Andrew H. Seltzer; Richard G. Herman

    2004-09-30

    Research is being conducted under United States Department of Energy (DOE) Contract DEFC26-03NT41865 to develop a new technology to achieve very low levels of NOx emissions from pulverized coal fired boiler systems by employing a novel system level integration between the PC combustion process and the catalytic NOx reduction with CO present in the combustion flue gas. The combustor design and operating conditions will be optimized to achieve atypical flue gas conditions. This approach will not only suppress NOx generation during combustion but also further reduce NOx over a downstream catalytic reactor that does not require addition of an external reductant, such as ammonia. This report describes the work performed during the July 1 to September 30, 2004 time period.

  6. Ammonia-Free NOx Control System

    Energy Technology Data Exchange (ETDEWEB)

    Song Wu; Zhen Fan; Andrew H. Seltzer

    2005-09-30

    Research is being conducted under United States Department of Energy (DOE) Contract DEFC26-03NT41865 to develop a new technology to achieve very low levels of NOx emissions from pulverized coal fired boiler systems by employing a novel system level integration between the PC combustion process and the catalytic NOx reduction with CO present in the combustion flue gas. The combustor design and operating conditions will be optimized to achieve atypical flue gas conditions. This approach will not only suppress NOx generation during combustion but also further reduce NOx over a downstream catalytic reactor that does not require addition of an external reductant, such as ammonia. This report describes the work performed during the July 1 to September 30, 2005 time period.

  7. Ammonia-Free NOx Control System

    Energy Technology Data Exchange (ETDEWEB)

    Song Wu; Zhen Fan; Richard G. Herman

    2004-12-31

    Research is being conducted under United States Department of Energy (DOE) Contract DEFC26-03NT41865 to develop a new technology to achieve very low levels of NOx emissions from pulverized coal fired boiler systems by employing a novel system level integration between the PC combustion process and the catalytic NOx reduction with CO present in the combustion flue gas. The combustor design and operating conditions will be optimized to achieve atypical flue gas conditions. This approach will not only suppress NOx generation during combustion but also further reduce NOx over a downstream catalytic reactor that does not require addition of an external reductant, such as ammonia. This report describes the work performed during the October 1 to December 30, 2004 time period.

  8. Modeling the selective catalytic reduction of NOx by ammonia over a Vanadia-based catalyst from heavy duty diesel exhaust gases

    International Nuclear Information System (INIS)

    Yun, Byoung Kyu; Kim, Man Young

    2013-01-01

    A numerical simulation for prediction of NO X conversion over a commercial V 2 O 5 catalyst with NH 3 as a reductant was performed for a heavy duty diesel engine applications. The chemical behaviors of the SCR reactor are described by using the global NO X kinetics including standard, fast, and NH 3 oxidation reactions with the Langmuir–Hinshelwood (LH) mechanism incorporated into the commercial Boost code. After introducing mathematical models for the SCR reaction with specific reaction parameters, the effects of various parameters such as space velocities, the O 2 , H 2 O, NO 2 , and NH 3 concentrations on the NOx conversion are thoroughly studied and validated by comparing with the experimental data available in the literature. It is found that NO X conversion increases with decreasing space velocity, H 2 O concentration, and NH 3 /NO X ratio, and increasing O 2 concentration and NO 2 /NO X ratio. The study shows that not only is the present approach adopted is flexible in treating performance of the commercial V 2 O 5 based SCR catalyst, it is also accurate and efficient for the prediction of NO X conversion in diesel exhaust environments. - Highlights: ► To find the reaction parameters for LH mechanism over a commercial V2O5 catalyst. ► To investigate the effects of various parameters on the SCR NO X conversion. ► To present benchmark solutions on SCR behavior with diesel exhaust environments.

  9. SOx-NOx-Rox Box{trademark} flue gas clean-up demonstration. Final report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-09-01

    Babcock and Wilcox`s (B and W) SOx-NOx-Rox Box{trademark} process effectively removes SOx, NOx and particulate (Rox) from flue gas generated from coal-fired boilers in a single unit operation, a high temperature baghouse. The SNRB technology utilizes dry sorbent injection upstream of the baghouse for removal of SOx and ammonia injection upstream of a zeolitic selective catalytic reduction (SCR) catalyst incorporated in the baghouse to reduce NOx emissions. Because the SOx and NOx removal processes require operation at elevated gas temperatures (800--900 F) for high removal efficiency, high-temperature fabric filter bags are used in the baghouse. The SNRB technology evolved from the bench and laboratory pilot scale to be successfully demonstrated at the 5-MWe field scale. This report represents the completion of Milestone M14 as specified in the Work Plan. B and W tested the SNRB pollution control system at a 5-MWe demonstration facility at Ohio Edison`s R.E. Burger Plant located near Shadyside, Ohio. The design and operation were influenced by the results from laboratory pilot testing at B and W`s Alliance Research Center. The intent was to demonstrate the commercial feasibility of the SNRB process. The SNRB facility treated a 30,000 ACFM flue gas slipstream from Boiler No. 8. Operation of the facility began in May 1992 and was completed in May 1993. About 2,300 hours of high-temperature operation were achieved. The main emissions control performance goals of: greater than 70% SO{sub 2} removal using a calcium-based sorbent; greater than 90% NOx removal with minimal ammonia slip; and particulate emissions in compliance with the New Source Performance Standards (NSPS) of 0.03 lb/million Btu were exceeded simultaneously in the demonstration program when the facility was operated at optimal conditions. Testing also showed significant reductions in emissions of some hazardous air pollutants.

  10. Commercial steam reforming catalysts to improve biomass gasification with steam-oxygen mixtures. 2: Catalytic tar removal

    Energy Technology Data Exchange (ETDEWEB)

    Aznar, M.P.; Caballero, M.A.; Gil, J.; Martin, J.A. [Univ. of Saragossa (Spain). Chemical and Environmental Engineering Dept.; Corella, J. [Univ. Complutense of Madrid (Spain). Chemical Engineering Dept.

    1998-07-01

    Eight different commercial catalysts, nickel based, for steam reforming of naphthas and of natural gas are tested in biomass gasification for hot gas cleanup and conditioning. They were manufactured by BASF AG, ICI-Katalco, UCI, and Haldor Topsoee a/s. The catalysts were tested in a slip flow after a biomass gasifier of fluidized bed type at small pilot-plant scale (10--20 kg of biomass/h). The gasifying agent used is steam-oxygen mixtures. A guard bed containing a calcined dolomite is used to decrease the tar content in the gas at the inlet of the catalytic bed. Main variables studied are catalyst type, bed temperature, H{sub 2}O + O{sub 2} to biomass feed ratio, and time-on-stream. All catalysts for reforming of naphthas show to be very active and useful for tar removal and gas conditioning (in biomass gasification). 98% tar removal is easily obtained with space velocities of 14,000 h{sup {minus}1} (n.c.). No catalysts deactivation is found in 48 h-on-stream tests when the catalyst temperature is relatively high (780--830 C). Using a simple first-order kinetic model for the overall tar removal reaction, apparent energies of activation (of around 58 kJ/mol) and preexponential factors are obtained for the most active catalysts.

  11. Ce1-xFexO2 nanocatalysts for priority organic pollutants removal through catalytic wet air oxidation

    Directory of Open Access Journals (Sweden)

    Anushree

    2017-12-01

    Full Text Available A series of Ce1-xFexO2 nanocatalysts, prepared by co-precipitation method, were applied for the catalytic oxidation of priority organic pollutants present in paper industry wastewater. To investigate the synergic effect of various Fe contents, detailed characterizations of Ce1-xFexO2 were done by Raman, XPS, XRD, TEM and EDX techniques. The addition of Fe to CeO2 lattice increased the amount of oxygen vacancies, which have an efficient role in the oxidation of organic pollutants under oxygen-rich conditions. Ce0.4Fe0.6O2 catalyst showed the highest removal of TOC (72%, AOX (68%, chlorophenols (62% and chloroguaicols (86%. The superior catalytic activity of Ce0.4Fe0.6O2 is ascribed to its higher oxygen vacancy concentration. The presence of two oxidation states of Ce (4+,3+ and Fe (3+,2+ confirmed the role of redox couples in oxidation of organic pollutants.

  12. A broad spectrum catalytic system for removal of toxic organics from water by deep oxidation. 1998 annual progress report

    International Nuclear Information System (INIS)

    Sen, A.

    1998-01-01

    'Toxic organics and polymers pose a serious threat to the environment, especially when they are present in aquatic systems. The objective of the research is the design of practical procedures for the removal and/or recycling of such pollutants by oxidation. This report summarizes the work performed in the first one and half years of a three year project. The authors had earlier described a catalytic system for the deep oxidation of toxic organics, such as benzene, phenol and substituted phenols, aliphatic and aromatic halogenated compounds, organophosphorus, and organosulfur compounds [1]. In this system, metallic palladium was found to catalyze the oxidation of the substrate by dioxygen in aqueous medium at 80--100 C in the presence of carbon monoxide. For all the substrates examined, deep oxidation to carbon monoxide, carbon dioxide, and water occurred in high yields, resulting in up to several hundred turnovers over a 24 h period. Because of a pressing need for new procedures for the destruction of chemical warfare agents, the authors have examined in detail the deep oxidation of appropriate model compounds containing phosphorus-carbon and sulfur-carbon bonds using the same catalytic system. The result is the first observation of the efficient catalytic oxidative cleavage of phosphorus-carbon and sulfur-carbon bonds under mild conditions, using dioxygen as the oxidant [2]. In addition to the achievements described above, they have unpublished results in several other areas. For example, they have investigated the possibility of using dihydrogen rather than carbon monoxide as a coreductant in the catalytic deep oxidation of substrates. Even more attractive from a practical standpoint is the possibility of using a mixture of carbon monoxide and dihydrogen (synthesis gas). Indeed, experiments indicated that it is possible to substitute carbon monoxide by dihydrogen or synthesis gas. Significantly, in the case of nitro compounds, the deep oxidation in fact proceeded

  13. Advanced oxidation removal of hypophosphite by O3/H2O2 combined with sequential Fe(II) catalytic process.

    Science.gov (United States)

    Zhao, Zilong; Dong, Wenyi; Wang, Hongjie; Chen, Guanhan; Wang, Wei; Liu, Zekun; Gao, Yaguang; Zhou, Beili

    2017-08-01

    Elimination of hypophosphite (HP) was studied as an example of nickel plating effluents treatment by O 3 /H 2 O 2 and sequential Fe(II) catalytic oxidation process. Performance assessment performed with artificial HP solution by varying initial pH and employing various oxidation processes clearly showed that the O 3 /H 2 O 2 ─Fe(II) two-step oxidation process possessed the highest removal efficiency when operating under the same conditions. The effects of O 3 dosing, H 2 O 2 concentration, Fe(II) addition and Fe(II) feeding time on the removal efficiency of HP were further evaluated in terms of apparent kinetic rate constant. Under improved conditions (initial HP concentration of 50 mg L -1 , 75 mg L -1 O 3 , 1 mL L -1 H 2 O 2 , 150 mg L -1 Fe(II) and pH 7.0), standard discharge (<0.5 mg L -1 in China) could be achieved, and the Fe(II) feeding time was found to be the limiting factor for the evolution of apparent kinetic rate constant in the second stage. Characterization studies showed that neutralization process after oxidation treatment favored the improvement of phosphorus removal due to the formation of more metal hydroxides. Moreover, as a comparison with lab-scale Fenton approach, the O 3 /H 2 O 2 ─Fe(II) oxidation process had more competitive advantages with respect to applicable pH range, removal efficiency, sludge production as well as economic costs. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Elementary steps of the catalytic NO(x) reduction with NH3: cluster studies on reactant adsorption at vanadium oxide substrate.

    Science.gov (United States)

    Gruber, M; Hermann, K

    2013-03-07

    Extended cluster models together with density-functional theory are used to evaluate geometric, energetic, and electronic properties of different adsorbate species that can occur at a vanadium oxide surface where the selective catalytic reduction (SCR) of NO in the presence of ammonia proceeds. Here, we focus on atomic hydrogen, nitrogen, and oxygen, as well as molecular NO and NHx, x = 1, 4, adsorption at a model V2O5(010) surface. Binding sites, oxygen and vanadium, at both the perfect and reduced surface are considered where reduction is modeled by (sub-) surface oxygen vacancies. The reactants are found to bind overall more strongly at oxygen vacancy sites of the reduced surface where they stabilize in positions formerly occupied by the oxygen (substitutional adsorption) compared with weaker binding at the perfect surface. In particular, ammonia, which interacts only weakly with vanadium at the perfect surface, binds quite strongly near surface oxygen vacancies. In contrast, surface binding of the NH4 adsorbate species differs only little between the perfect and the reduced surface which is explained by the dominantly electrostatic nature of the adsorbate interaction. The theoretical results are consistent with experimental findings and confirm the importance of surface reduction for the reactant adsorption forming elementary steps of the SCR process.

  15. Life cycle assessment of selective non-catalytic reduction (SNCR) of nitrous oxides in a full-scale municipal solid waste incinerator

    DEFF Research Database (Denmark)

    Møller, Jacob; Munk, Bjarne; Crillesen, Kim

    2011-01-01

    Selective non-catalytic reduction (SNCR) of nitrous oxides in a full-scale municipal solid waste incinerator was investigated using LCA. The relationship between NOx-cleaning and ammonia dosage was measured at the plant. Un-reacted ammonia – the ammonia slip – leaving the flue-gas cleaning system......-removal in flue-gas cleaning from waste incineration....

  16. Utilization of catalytic hydrolysis of ethyl acetate for solvent removal during microencapsulation.

    Science.gov (United States)

    Lee, Minjung; Kang, Jookyung; Sah, Hongkee

    2013-01-01

    The objective of this study was to apply the specific acid-catalysed hydrolysis of ethyl acetate to completing solvent extraction during an emulsion-based microencapsulation process. The dispersed phase consisting of poly-D,L-lactide-co-glycolide and ethyl acetate was emulsified in an acid catalyst containing aqueous phase. Catalytic hydrolysis of ethyl acetate led to its continual leaching from the dispersed phase of the emulsion, thereby triggering microsphere hardening with high efficiency. Ketoprofen was successfully encapsulated into microspheres via this technique, and liquid chromatography-mass spectrometry showed that its structural integrity was preserved during microencapsulation. Compared to typical solvent extraction approaches, the acid-catalysis technique helped minimize the consumption of a quench liquid. Also, the resultant microspheres displayed excellent dispersibility and decreased propensity for aggregation. Furthermore, the new method provided better drug encapsulation efficiency and lower levels of residual ethyl acetate in microspheres. In conclusion, the acid-catalysis approach had great potential for the preparation of versatile microspheres and nanoparticles.

  17. Removal of diatrizoate with catalytically active membranes incorporating microbially produced palladium nanoparticles.

    Science.gov (United States)

    Hennebel, Tom; De Corte, Simon; Vanhaecke, Lynn; Vanherck, Katrien; Forrez, Ilse; De Gusseme, Bart; Verhagen, Pieter; Verbeken, Kim; Van der Bruggen, Bart; Vankelecom, Ivo; Boon, Nico; Verstraete, Willy

    2010-03-01

    There is an increasing concern about the fate of iodinated contrast media (ICM) in the environment. Limited removal efficiencies of currently applied techniques such as advanced oxidation processes require more performant strategies. The aim of this study was to establish an innovative degradation process for diatrizoate, a highly recalcitrant ICM, by using biogenic Pd nanoparticles as free suspension or immobilized in polyvinylidene fluoride (PVDF) and polysulfone (PSf) membranes. As measured by HPLC-UV, the removal of 20mg L(-1) diatrizoate by a 10mg L(-1) Pd suspension was completed after 4h at a pH of 10. LC-MS analysis provided evidence for the sequential hydrodeiodination of diatrizoate. Pd did not lose its activity after incorporation in the PVDF and PSf matrix and the highest activity (k(cat)=30.0+/-0.4h(-1) L g(-1) Pd) was obtained with a casting solution of 10% PSf and 500mg L(-1) Pd. Subsequently, water containing 20mg L(-1) diatrizoate was treated in a membrane contactor, in which the water was supplied at one side of the membrane while hydrogen was provided at the other side. In a fed batch configuration, a removal efficiency of 77% after a time period of 48h was obtained. This work showed that membrane contactors with encapsulated biogenic nanoparticles can be instrumental for treatment of water contaminated with diatrizoate. Copyright 2009 Elsevier Ltd. All rights reserved.

  18. Mitoxantrone removal by electrochemical method: A comparison of homogenous and heterogenous catalytic reactions

    Directory of Open Access Journals (Sweden)

    Abbas Jafarizad

    2017-08-01

    Full Text Available Background: Mitoxantrone (MXT is a drug for cancer therapy and a hazardous pharmaceutical to the environment which must be removed from contaminated waste streams. In this work, the removal of MXT by the electro-Fenton process over heterogeneous and homogenous catalysts is reported. Methods: The effects of the operational conditions (reaction medium pH, catalyst concentration and utilized current intensity were studied. The applied electrodes were carbon cloth (CC without any processing (homogenous process, graphene oxide (GO coated carbon cloth (GO/CC (homogenous process and Fe3O4@GO nanocomposite coated carbon cloth (Fe3O4@GO/CC (heterogeneous process. The characteristic properties of the electrodes were determined by atomic force microscopy (AFM, field emission scanning electron microscopy (FE-SEM and cathode polarization. MXT concentrations were determined by using ultraviolet-visible (UV-Vis spectrophotometer. Results: In a homogenous reaction, the high concentration of Fe catalyst (>0.2 mM decreased the MXT degradation rate. The results showed that the Fe3O4@GO/CC electrode included the most contact surface. The optimum operational conditions were pH 3.0 and current intensity of 450 mA which resulted in the highest removal efficiency (96.9% over Fe3O4@GO/CC electrode in the heterogeneous process compared with the other two electrodes in a homogenous process. The kinetics of the MXT degradation was obtained as a pseudo-first order reaction. Conclusion: The results confirmed the high potential of the developed method to purify contaminated wastewaters by MXT.

  19. Method for removing strongly adsorbed surfactants and capping agents from metal to facilitate their catalytic applications

    Science.gov (United States)

    Adzic, Radoslav R.; Gong, Kuanping; Cai, Yun; Wong, Stanislaus; Koenigsmann, Christopher

    2016-11-08

    A method of synthesizing activated electrocatalyst, preferably having a morphology of a nanostructure, is disclosed. The method includes safely and efficiently removing surfactants and capping agents from the surface of the metal structures. With regard to metal nanoparticles, the method includes synthesis of nanoparticle(s) in polar or non-polar solution with surfactants or capping agents and subsequent activation by CO-adsorption-induced surfactant/capping agent desorption and electrochemical oxidation. The method produces activated macroparticle or nanoparticle electrocatalysts without damaging the surface of the electrocatalyst that includes breaking, increasing particle thickness or increasing the number of low coordination sites.

  20. Fast microwave-assisted catalytic gasification of biomass for syngas production and tar removal.

    Science.gov (United States)

    Xie, Qinglong; Borges, Fernanda Cabral; Cheng, Yanling; Wan, Yiqin; Li, Yun; Lin, Xiangyang; Liu, Yuhuan; Hussain, Fida; Chen, Paul; Ruan, Roger

    2014-03-01

    In the present study, a microwave-assisted biomass gasification system was developed for syngas production. Three catalysts including Fe, Co and Ni with Al2O3 support were examined and compared for their effects on syngas production and tar removal. Experimental results showed that microwave is an effective heating method for biomass gasification. Ni/Al2O3 was found to be the most effective catalyst for syngas production and tar removal. The gas yield reached above 80% and the composition of tar was the simplest when Ni/Al2O3 catalyst was used. The optimal ratio of catalyst to biomass was determined to be 1:5-1:3. The addition of steam was found to be able to improve the gas production and syngas quality. Results of XRD analyses demonstrated that Ni/Al2O3 catalyst has good stability during gasification process. Finally, a new concept of microwave-assisted dual fluidized bed gasifier was put forward for the first time in this study. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Sustained Low Temperature NOx Reduction

    Energy Technology Data Exchange (ETDEWEB)

    Zha, Yuhui

    2017-04-05

    Increasing regulatory, environmental, and customer pressure in recent years led to substantial improvements in the fuel efficiency of diesel engines, including the remarkable breakthroughs demonstrated through the Super Truck program supported by the U.S. Department of Energy (DOE). On the other hand, these improvements have translated into a reduction of exhaust gas temperatures, thus further complicating the task of controlling NOx emissions, especially in low power duty cycles. The need for improved NOx conversion over these low temperature duty cycles is also observed as requirements tighten with in-use emissions testing. Sustained NOx reduction at low temperatures, especially in the 150-200oC range, shares some similarities with the more commonly discussed cold-start challenge, however poses a number of additional and distinct technical problems. In this project we set a bold target of achieving and maintaining a 90% NOx conversion at the SCR catalyst inlet temperature of 150oC. The project is intended to push the boundaries of the existing technologies, while staying within the realm of realistic future practical implementation. In order to meet the resulting challenges at the levels of catalyst fundamentals, system components, and system integration, Cummins has partnered with the DOE, Johnson Matthey, and Pacific Northwest National Lab and initiated the Sustained Low-Temperature NOx Reduction program at the beginning of 2015. Through this collaboration, we are exploring catalyst formulations and catalyst architectures with enhanced catalytic activity at 150°C; opportunities to approach the desirable ratio of NO and NO2 in the SCR feed gas; options for robust low-temperature reductant delivery; and the requirements for overall system integration. The program is expected to deliver an on-engine demonstration of the technical solution and an assessment of its commercial potential. In the SAE meeting, we will share the initial performance data on engine to

  2. Investigation of tritium removal by means of organic compounds. Catalytic hydrogenation (tritiation) of linoleic acid

    International Nuclear Information System (INIS)

    El-Sharnouby, A.; Weichselgartner, H.

    1984-11-01

    In the presence of noble-metal catalysts unsaturated fatty acids such as eruic acid and linoleic acid capture hydrogen (and tritium) quantitatively. The hydrogenation reaction of eruic acid has already been reported. The experimental results of the reaction of hydrogen (and tritium) with linoleic acid are now discussed in this paper. Obviously, the use of linoleic acid shows some advantages compared with eruic acid: - the hydrogenation reaction is faster, - linoleic acid is liquid, so that the choice of additional solvents is easier, and - linoleic acid is a more or less cheap natural product, which is available from a series of seeds, so that the cost of a technical tritium removal plant is not increased by the basic chemical material. (orig.)

  3. NOx emissions in gas turbines: formation mechanism and reduction; Emissoes de NOx em turbinas a gas: mecanismos de formacao e algumas tecnologias de reducao

    Energy Technology Data Exchange (ETDEWEB)

    Gallego, Antonio Garrido; Martins, Gilberto; Gallo, Waldyr L.R. [Universidade Metodista de Piracicaba, SP (Brazil)]. E-mails: agallego@unimep.br; gmartins@unimep.br; gallo@fem.unicamp.br

    2000-06-01

    Some aspects related to the NOx emissions from industrial gas turbines are studied. Brazilian and international emission regulations are discussed. The main oxide formation mechanisms inside the combustion chamber are presented, and the main strategies for the reduction of NOx emission are explored (including water and steam injection, staged combustion, low-NOx burners and catalytic reduction). The need for a revision on Brazilian regulations for NOx is evidenced. (author)

  4. Evaluation of Performance Catalytic Ozonation with Activated Alumina in the Removal of Pentachlorophenol from Aqueous Solutions and Study of the Intermediates

    Directory of Open Access Journals (Sweden)

    A.R. Rahmani

    2013-04-01

    Full Text Available Introduction & Objective: Pentachlorophenol (PCP is a refractory phenolic compound. Owing to its high poisonous and carcinogenic nature, PCP is on the US EPA’s list of priority pollut-ants. As a result, it is one of the important pollutants that need to be removed during water and wastewater reclamation processes. The efficiency of the catalytic ozonation process (COP was assessed based on the removal of PCP from the aqueous solutions and its inter-mediates were studied. Materials & Methods: In this experimental study, catalytic ozonation process was applied to remove PCP in aqueous solution and its intermediate was studied. The influence of several variables was examined, including pH of solution, contact time, dissolved ozone concentra-tion and dosage of -Al2O3 in semi batch reactor. The determination of PCP concentrations in solutions was analyzed by HPLC using the UV detector (254nm. Results: Our results showed that the removal effectiveness of PCP has been increased by ris-ing pH, contact time, catalyst dosage and dissolved ozone concentration. Removal efficiency of PCP was determined 89% and 100% in SOP and AOP after 60 minutes, respectively. The pHzpc of alumina was determined 8.6. Conclusion: Due to high performance of -Al2O3 as catalyst in catalytic ozonation and increas-ing the PCP removal, it is thus concluded that the integrated catalytic ozonation is a promis-ing and economically affordable technology for the treatment of wastewater containing pen-tachlorophenol and other similar compounds. (Sci J Hamadan Univ Med Sci 2013; 20 (1:77-85

  5. Removal and Conversion of Tar in Syngas from Woody Biomass Gasification for Power Utilization Using Catalytic Hydrocracking

    Directory of Open Access Journals (Sweden)

    Jiu Huang

    2011-08-01

    Full Text Available Biomass gasification has yet to obtain industrial acceptance. The high residual tar concentrations in syngas prevent any ambitious utilization. In this paper a novel gas purification technology based on catalytic hydrocracking is introduced, whereby most of the tarry components can be converted and removed. Pilot scale experiments were carried out with an updraft gasifier. The hydrocracking catalyst was palladium (Pd. The results show the dominant role of temperature and flow rate. At a constant flow rate of 20 Nm3/h and temperatures of 500 °C, 600 °C and 700 °C the tar conversion rates reached 44.9%, 78.1% and 92.3%, respectively. These results could be increased up to 98.6% and 99.3% by using an operating temperature of 700 °C and lower flow rates of 15 Nm3/h and 10 Nm3/h. The syngas quality after the purification process at 700 °C/10 Nm3/h is acceptable for inner combustion (IC gas engine utilization.

  6. Mesostructured Cu–Mn–Ce–O composites with homogeneous bulk composition for chlorobenzene removal: Catalytic performance and microactivation course

    Energy Technology Data Exchange (ETDEWEB)

    He, Chi, E-mail: chi_he@mail.xjtu.edu.cn [Department of Environmental Science and Engineering, School of Energy and Power Engineering, Xi' an Jiaotong University, Xi' an 710049 (China); Yu, Yanke [Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021 (China); Shi, Jianwen [Center of Nanomaterials for Renewable Energy, State Key Laboratory of Electrical Insulation and Power Equipment, School of Electrical Engineering, Xi' an Jiaotong University, Xi' an 710049 (China); Shen, Qun [Research Center for Greenhouse Gases and Environmental Engineering, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201210 (China); Chen, Jinsheng [Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021 (China); Liu, Hongxia, E-mail: hxliu72@mail.xjtu.edu.cn [Department of Environmental Science and Engineering, School of Energy and Power Engineering, Xi' an Jiaotong University, Xi' an 710049 (China)

    2015-05-01

    Cu–Mn–Ce–O composites with enhanced surface area and developed mesoporosity were synthesized using a homogeneous coprecipitation (hcp) method, and were tested in the catalytic destruction of chlorobenzene (CB). X-ray diffraction (XRD), N{sub 2} adsorption/desorption, field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), temperature programmed reduction (H{sub 2}-TPR), temperature programmed desorption of CB/O{sub 2} (CB/O{sub 2}-TPD), and diffuse reflectance ultraviolet visible spectroscopy (DRUV-Vis) were used to characterize the structure and textural properties of catalysts. Mn and Cu enter CeO{sub 2} matrix with a fluorite-like structure, and produce large amounts of oxygen vacancies. Addition of manganese promotes the formation of reduced copper phase, and the presence of large numbers of high valence Mn{sup 4+} ions strongly enhances the redox couple of Cu{sup +}–Cu{sup 2+} in the composites. Both the synthesis protocol and metal doping amount significantly affect the catalyst reducibility, surface state and oxygen density. Cu{sub 0.15}Mn{sub 0.15}Ce{sub 0.85}O{sub x} synthesized via the hcp method exhibits the highest catalytic activity with 90% of chlorobenzene destructed at 255 °C (CO{sub 2} selectivity > 99.5%). Enriched surface oxygen, excellent active oxygen mobility and CB adsorption ability guarantee the superior activity and stability of Cu–Mn–Ce–O composite catalysts. Nucleophilic and electrophilic substitutions happen in sequence during chlorobenzene destruction, and the adsorbed Cl can be finally removed in the form of Cl{sub 2} via the Deacon reaction. Furthermore, the incorporation of CuO and MnO{sub x} phases can inhibit the formation of organic byproducts, such as phenolates, maleates, and o-benzoquinone-type species, especially at elevated reaction temperatures. - Highlights: • Cu–Mn–Ce–O mesoporous oxides possess enhanced surface oxygen

  7. Nox1-dependent superoxide production controls colon adenocarcinoma cell migration.

    Science.gov (United States)

    Sadok, Amine; Bourgarel-Rey, Véronique; Gattacceca, Florence; Penel, Claude; Lehmann, Maxime; Kovacic, Hervé

    2008-01-01

    Reactive oxygen species are well-known mediators of various biological responses. Recently, new homologues of the catalytic subunit of NADPH oxidase have been discovered in non-phagocytic cells. These new homologues (Nox1-Nox5) produce low levels of superoxides compared to the phagocytic homologue Nox2/gp91phox. Using Nox1 siRNA, we show that Nox1-dependent superoxide production affects the migration of HT29-D4 colonic adenocarcinoma cells on collagen-I. Nox1 inhibition or down-regulation led to a decrease of superoxide production and alpha 2 beta 1 integrin membrane availability. An addition of arachidonic acid stimulated Nox1-dependent superoxide production and HT29-D4 cell migration. Pharmacological evidences using phospholipase A2, lipoxygenases and protein kinase C inhibitors show that upstream regulation of Nox1 relies on arachidonic acid metabolism. Inhibition of 12-lipoxygenase decreased basal and arachidonic acid induced Nox1-dependent superoxide production and cell migration. Migration and ROS production inhibited by a 12-lipoxygenase inhibitor were restored by the addition of 12(S)-HETE, a downstream product of 12-lipoxygenase. Protein kinase C delta inhibition by rottlerin (and also GO6983) prevented Nox1-dependent superoxide production and inhibited cell migration, while other protein kinase C inhibitors were ineffective. We conclude that Nox1 activation by arachidonic acid metabolism occurs through 12-lipoxygenase and protein kinase C delta, and controls cell migration by affecting integrin alpha 2 subunit turn-over.

  8. Nitrogen stable isotope composition (δ15N) of vehicle-emitted NOx.

    Science.gov (United States)

    Walters, Wendell W; Goodwin, Stanford R; Michalski, Greg

    2015-02-17

    The nitrogen stable isotope ratio of NOx (δ(15)N-NOx) has been proposed as a regional indicator for NOx source partitioning; however, knowledge of δ(15)N values from various NOx emission sources is limited. This study presents a detailed analysis of δ(15)N-NOx emitted from vehicle exhaust, the largest source of anthropogenic NOx. To accomplish this, NOx was collected from 26 different vehicles, including gasoline and diesel-powered engines, using a modification of a NOx collection method used by the United States Environmental Protection Agency, and δ(15)N-NOx was analyzed. The vehicles sampled in this study emitted δ(15)N-NOx values ranging from -19.1 to 9.8‰ that negatively correlated with the emitted NOx concentrations (8.5 to 286 ppm) and vehicle run time because of kinetic isotope fractionation effects associated with the catalytic reduction of NOx. A model for determining the mass-weighted δ(15)N-NOx from vehicle exhaust was constructed on the basis of average commute times, and the model estimates an average value of -2.5 ± 1.5‰, with slight regional variations. As technology improvements in catalytic converters reduce cold-start emissions in the future, it is likely to increase current δ(15)N-NOx values emitted from vehicles.

  9. Removal of volatile to semi-volatile organic contaminants from water using hollow fiber membrane contactors and catalytic destruction of the contaminants in the gas phase

    OpenAIRE

    Tarafder, Shamsul Abedin

    2007-01-01

    Abstract Chlorinated organic compounds and ether compounds are frequently found in groundwater and efficient treatment options are needed. In this study, the efficient transferal of the compounds from the water phase to the gas phase was studied followed by the catalytic treatment of the gas phase. For the removal of the organic contaminants from water, a microporous polypropylene hollow fiber membrane (HFM) module was operated under low strip gas flow to water flow ratios (_< 5:1). Rem...

  10. NOx Control Options and Integration for US Coal Fired Boilers

    Energy Technology Data Exchange (ETDEWEB)

    Mike Bockelie; Marc Cremer; Kevin Davis; Martin Denison; Adel Sarofim; Connie Senior; Hong-Shig Shim; Dave Swenson; Bob Hurt; Eric Suuberg; Eric Eddings; Kevin Whitty; Larry Baxter; Calvin Bartholomew; William Hecker

    2006-06-30

    This is the Final Report for DOE Cooperative Agreement No: DE-FC26-00NT40753. The goal of the project was to develop cost-effective analysis tools and techniques for demonstrating and evaluating low-NOx control strategies and their possible impact on boiler performance for boilers firing US coals. The Electric Power Research Institute (EPRI) provided co-funding for this program. This project included research on: (1) In furnace NOx control; (2) Impacts of combustion modifications on boiler operation; (3) Selective Catalytic Reduction (SCR) catalyst testing and (4) Ammonia adsorption/removal on fly ash. Important accomplishments were achieved in all aspects of the project. Rich Reagent Injection (RRI), an in-furnace NOx reduction strategy based on injecting urea or anhydrous ammonia into fuel rich regions in the lower furnace, was evaluated for cyclone-barrel and PC fired utility boilers. Field tests successfully demonstrated the ability of the RRI process to significantly reduce NOx emissions from a staged cyclone-fired furnace operating with overfire air. The field tests also verified the accuracy of the Computational Fluid Dynamic (CFD) modeling used to develop the RRI design and highlighted the importance of using CFD modeling to properly locate and configure the reagent injectors within the furnace. Low NOx firing conditions can adversely impact boiler operation due to increased waterwall wastage (corrosion) and increased soot production. A corrosion monitoring system that uses electrochemical noise (ECN) corrosion probes to monitor, on a real-time basis, high temperature corrosion events within the boiler was evaluated. Field tests were successfully conducted at two plants. The Ohio Coal Development Office provided financial assistance to perform the field tests. To investigate soot behavior, an advanced model to predict soot production and destruction was implemented into an existing reacting CFD modeling tool. Comparisons between experimental data collected

  11. Non-Thermal Removal of Gaseous Pollutants

    Science.gov (United States)

    Srivastava, S.; McGowan, J. William; Chiu, K. C. Ray

    1995-01-01

    The removal of fluorine based exhaust gases such as CFC's, PFC's, NF3, and SF6 used for plasma etching of and deposition on semi-conductors is a subject of increasing interest because of safety, air pollution, and global warming issues. Conventional treatment methods for removing exhaust gas pollutants are wet scrubbing, carbon and resin adsorption, catalytic oxidation, and thermal incineration. However, there are drawbacks associated with each of these methods which include difficulties in implementation, problems with the disposal of solid and liquid pollutant waste, large water and fuel consumption, and additional pollutants such as NOx emissions which are generated in thermal incineration processes.

  12. Removal of ethylene from air stream by adsorption and plasma-catalytic oxidation using silver-based bimetallic catalysts supported on zeolite.

    Science.gov (United States)

    Trinh, Quang Hung; Lee, Sang Baek; Mok, Young Sun

    2015-03-21

    Dynamic adsorption of ethylene on 13X zeolite-supported Ag and Ag-M(x)O(y) (M: Co, Cu, Mn, and Fe), and plasma-catalytic oxidation of the adsorbed ethylene were investigated. The experimental results showed that the incorporation of Ag into zeolite afforded a marked enhancement in the adsorptivity for ethylene. The addition of transition metal oxides was found to have a positive influence on the ethylene adsorption, except Fe(x)O(y). The presence of the additional metal oxides, however, appeared to somewhat interrupt the diffusion of ozone into the zeolite micro-pores, leading to a decrease in the plasma-catalytic oxidation efficiency of the ethylene adsorbed there. Among the second additional metal oxides, Fe(x)O(y) was able to reduce the emission of ozone during the plasma-catalytic oxidation stage while keeping a high effectiveness for the oxidative removal of the adsorbed ethylene. The periodical treatment consisting of adsorption followed by plasma-catalytic oxidation may be a promising energy-efficient ethylene abatement method. Copyright © 2014 Elsevier B.V. All rights reserved.

  13. Innovative clean coal technology (ICCT): demonstration of selective catalytic reduction (SCR) technology for the control of nitrogen oxide (NOx) emission from high-sulfur, coal-fired boilers - economic evaluation of commercial-scale SCR applications for utility boilers

    International Nuclear Information System (INIS)

    Healy, E.C.; Maxwell, J.D.; Hinton, W.S.

    1996-09-01

    This report presents the results of an economic evaluation produced as part of the Innovative Clean Coal Technology project, which demonstrated selective catalytic reduction (SCR) technology for reduction of NO x emissions from utility boilers burning U.S. high-sulfur coal. The document includes a commercial-scale capital and O ampersand M cost evaluation of SCR technology applied to a new facility, coal-fired boiler utilizing high-sulfur U.S. coal. The base case presented herein determines the total capital requirement, fixed and variable operating costs, and levelized costs for a new 250-MW pulverized coal utility boiler operating with a 60-percent NO x removal. Sensitivity evaluations are included to demonstrate the variation in cost due to changes in process variables and assumptions. This report also presents the results of a study completed by SCS to determine the cost and technical feasibility of retrofitting SCR technology to selected coal-fired generating units within the Southern electric system

  14. Nox and renal disease.

    Science.gov (United States)

    Holterman, Chet E; Read, Naomi C; Kennedy, Chris R J

    2015-04-01

    Since the first demonstration of Nox enzyme expression in the kidney in the early 1990s and the subsequent identification of Nox4, or RENOX, a decade later, it has become apparent that the Nox family of reactive oxygen species (ROS) generating enzymes plays an integral role in the normal physiological function of the kidney. As our knowledge of Nox expression patterns and functions in various structures and specialized cell types within the kidney grows, so does the realization that Nox-derived oxidative stress contributes significantly to a wide variety of renal pathologies through their ability to modify lipids and proteins, damage DNA and activate transcriptional programmes. Diverse studies demonstrate key roles for Nox-derived ROS in kidney fibrosis, particularly in settings of chronic renal disease such as diabetic nephropathy. As the most abundant Nox family member in the kidney, much emphasis has been placed on the role of Nox4 in this setting. However, an ever growing body of work continues to uncover key roles for other Nox family members, not only in diabetic kidney disease, but in a diverse array of renal pathological conditions. The objective of the present review is to highlight the latest novel developments in renal Nox biology with an emphasis not only on diabetic nephropathy but many of the other renal disease contexts where oxidative stress is implicated.

  15. Removal of selected nitrogenous heterocyclic compounds in biologically pretreated coal gasification wastewater (BPCGW) using the catalytic ozonation process combined with the two-stage membrane bioreactor (MBR).

    Science.gov (United States)

    Zhu, Hao; Han, Yuxing; Ma, Wencheng; Han, Hongjun; Ma, Weiwei

    2017-12-01

    Three identical anoxic-aerobic membrane bioreactors (MBRs) were operated in parallel for 300 consecutive days for raw (R 1 ), ozonated (R 2 ) and catalytic ozonated (R 3 ) biologically pretreated coal gasification wastewater (BPCGW) treatment. The results demonstrated that catalytic ozonation process (COP) applied asa pretreatment remarkably improved the performance of the unsatisfactory single MBR. The overall removal efficiencies of COD, NH 3 -N and TN in R 3 were 92.7%, 95.6% and 80.6%, respectively. In addition, typical nitrogenous heterocyclic compounds (NHCs) of quinoline, pyridine and indole were completely removed in the integrated process. Moreover, COP could alter sludge properties and reshape microbial community structure, thus delaying the occurrence of membrane fouling. Finally, the total cost for this integrated process was estimated to be lower than that of single MBR. The results of this study suggest that COP is a good option to enhance pollutants removal and alleviate membrane fouling in the MBR for BPCGW treatment. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Reburning technology - a means to reduce NOx emissions

    International Nuclear Information System (INIS)

    Kremer, H.; Lorra, M.

    1999-01-01

    Nitrogen oxide emission control technologies can be classified as either combustion modifications to minimize the NO production or post-combustion flue gas treatment to reduce the NO concentration afterwards. The techniques for minimizing NOx Production includes the use of low-NOx burners, overfire air (staged combustion) and boiler combustion optimization. Procedures for flue gas treatment can be subdivided into selective catalytic reduction (SCR) or selective non-catalytic reduction (SNCR). The re burning process is a selective non-catalytic technology which is applicable to a wide variety of boilers and can be implemented within a relatively short period of time. The NOx reduction potential of this technique is in the range of 50 % up to 70 %. (author)

  17. Process for catalytic flue gas denoxing

    International Nuclear Information System (INIS)

    Woldhuis, A.; Goudriaan, F.; Groeneveld, M.; Samson, R.

    1991-01-01

    With the increasing concern for the environment, stringency of legislation and industry's awareness of its own environmental responsibility, the demand for the reduction of emission levels of nitrogen oxides is becoming increasingly urgent. This paper reports that Shell has developed a low temperature catalytic deNOx system for deep removal of nitrogen oxides, which includes a low-pressure-drop reactor. This process is able to achieve over 90% removal of nitrogen oxides and therefore can be expected to meet legislation requirements for the coming years. The development of a low-temperature catalyst makes it possible to operate at temperatures as low as 120 degrees C, compared to 300-400 degrees C for the conventional honeycomb and plate-type catalysts. This allows an add-on construction, which is most often a more economical solution than the retrofits in the hot section required with conventional deNOx catalysts. The Lateral Flow Reactor (LFR), which is used for dust-free flue gas applications, and the Parallel Passage Reactor (PPR) for dust-containing flue gas applications, have been developed to work with pressure drops below 10 mbar

  18. Determination of empirical models of NOx and SO2 removal efficiency for two steps of combustion gas irradiation system basing on results obtained at EPS Kaweczyn pilot plant

    International Nuclear Information System (INIS)

    Chmielewski, A.G.; Tyminski, B.; Dobrowolski, A.; Licki, J.

    1998-01-01

    A multidimensional regression method has been applied to construct empirical models equations of NO x and SO 2 removal efficiency in e-b process for two stage irradiation system basing on results achieved for EPS Kaweczyn pilot plant. Model equations describe with satisfactory accuracy experimental results, therefore obtained model equations can be used for prediction of NO x and SO 2 removal efficiency in e-b process during two stages irradiation of flue gases particularly in case of scale-up. (author)

  19. Nox2 B-loop Peptide, Nox2ds, Specifically Inhibits Nox2 Oxidase

    OpenAIRE

    Csányi, Gábor; Cifuentes-Pagano, Eugenia; Ghouleh, Imad Al; Ranayhossaini, Daniel J; Egaña, Loreto; Lopes, Lucia R.; Jackson, Heather M.; Kelley, Eric E.; Pagano, Patrick J.

    2011-01-01

    In recent years, reactive oxygen species (ROS) derived from the vascular isoforms of NADPH oxidase, Nox1, Nox2 and Nox4, have been implicated in many cardiovascular pathologies. As a result, the selective inhibition of these isoforms is an area of intense current investigation. In the present study, we postulated that Nox2ds, a peptidic inhibitor that mimics a sequence in the cytosolic B loop of Nox2, would inhibit ROS production by Nox2-, but not by Nox1- and Nox4-oxidase systems. To test ou...

  20. Urea-SCR technology for deNOx after treatment of diesel exhausts

    CERN Document Server

    Nova, Isabella

    2014-01-01

    Of intense interest both to academics and industry professionals, this groundbreaking book-length treatment of selective catalytic reduction of NOx using ammonia/urea includes papers by researchers at the leading edge of diesel exhaust abatement.

  1. Reducing diesel NOx and PM emissions of diesel buses and trucks.

    Science.gov (United States)

    2008-07-01

    The objective of the present investigation was development of a high efficiency : selective catalytic reduction (SCR) system for reducing diesel nitrogen oxides (NOx) and : particulate matters of diesel trucks. The investigation was divided into two ...

  2. Ammonia and water sorption properties of the mineral-layered nanomaterials used as the catalysts for NOx removal from exhaust gases

    International Nuclear Information System (INIS)

    Olszewska, D.

    2006-01-01

    The object of the study is the influence of acidity and hydrophilic properties of the surface of catalyst of the selective catalytic reduction (SCR) of nitrogen oxides by NH 3 . A series of catalysts prepared with the ZrO 2 -pillared montmorillonite from Jelsovy Potok have been promoted with manganese oxides. A part of the Na + -montmorillonite form has provisionally been treated with the 20% HCl. The acidity of materials was studied by the ammonia adsorption method at the temperature of 273 and 373K. Acidic properties of catalysts depend on the step of the support preparation-the acidic activation. The activity of the SCR reaction of acid untreated support and the catalyst with MnO x which had few stronger acid centres was lower than the activity of the acid pre-treated catalyst. In this case the support had more strong acid centres. The active material of MnO x increased the NO conversion but not the influence on the amount of ammonia sorption. These centres are probably not acidic centers. The hydrophilic properties were studied by water vapour sorption at the temperature of 298K. All the samples adsorbed the same amount of water, which suggests that the NO conversion does not influence hydrophilic properties. Water molecules were physically sorbed on the surface of materials and they were replaced with NH 3 in the presence of ammonia. (author)

  3. The Investigation of Electron Beam Catalytical Oxidation Process Efficiency with Potassium Persulfate in Removal Humic Acid from Aqueous Solutions

    Directory of Open Access Journals (Sweden)

    MT Ghaneian

    2015-05-01

    Results: Based on the results, changes in pH had little effect on the Humic acid removal efficiency. The average, with increasing of pH from 4 to 10, the removal efficiency of humic acid from 72.59% to 73.36% increased, respectively. The results showed that increasing of the dose from 1 to 15 kGy, humic acid removal efficiency increases. Based on results by increasing of persulfate concentration, the removal efficiency increased so that with increasing of concentration of potassium persulfate from 0.1 to 0.5 mmol/100cc, removal efficiency from 69.43% to 83.82% was increased. Kinetic experiments showed that the decomposition of humic acid by electron beam radiation followed the second-order kinetic. Conclusion: The data from this study showed that the aqueous solution containing acid Humic is decomposed effectively by electron beams irradiation. Addition of potassium persulfate can be have significant improvements in removal efficiency of humic acid in the presence of electron beam.

  4. NOx trade. Case studies

    International Nuclear Information System (INIS)

    Jantzen, J.

    2002-01-01

    Some of the questions with respect to the trade of nitrogen oxides that businesses in the Netherlands have to deal with are dealt with: should a business buy or sell rights for NOx emission; which measures must be taken to reduce NOx emission; how much must be invested; and how to deal with uncertainties with regard to prices. Simulations were carried out with the MOSES model to find the answers to those questions. Results of some case studies are presented, focusing on the chemical sector in the Netherlands. Finally, the financial (dis)advantages of NOx trade and the related uncertainties for a single enterprise are discussed [nl

  5. Optical and Electronic NOx Sensors for Applications in Mechatronics

    Directory of Open Access Journals (Sweden)

    Scott D. Wolter

    2009-05-01

    Full Text Available Current production and emerging NOx sensors based on optical and nanomaterials technologies are reviewed. In view of their potential applications in mechatronics, we compared the performance of: i Quantum cascade lasers (QCL based photoacoustic (PA systems; ii gold nanoparticles as catalytically active materials in field-effect transistor (FET sensors, and iii functionalized III-V semiconductor based devices. QCL-based PA sensors for NOx show a detection limit in the sub part-per-million range and are characterized by high selectivity and compact set-up. Electrochemically synthesized gold-nanoparticle FET sensors are able to monitor NOx in a concentration range from 50 to 200 parts per million and are suitable for miniaturization. Porphyrin-functionalized III-V semiconductor materials can be used for the fabrication of a reliable NOx sensor platform characterized by high conductivity, corrosion resistance, and strong surface state coupling.

  6. Optical and Electronic NOx Sensors for Applications in Mechatronics

    Science.gov (United States)

    Di Franco, Cinzia; Elia, Angela; Spagnolo, Vincenzo; Scamarcio, Gaetano; Lugarà, Pietro Mario; Ieva, Eliana; Cioffi, Nicola; Torsi, Luisa; Bruno, Giovanni; Losurdo, Maria; Garcia, Michael A.; Wolter, Scott D.; Brown, April; Ricco, Mario

    2009-01-01

    Current production and emerging NOx sensors based on optical and nanomaterials technologies are reviewed. In view of their potential applications in mechatronics, we compared the performance of: i) Quantum cascade lasers (QCL) based photoacoustic (PA) systems; ii) gold nanoparticles as catalytically active materials in field-effect transistor (FET) sensors, and iii) functionalized III-V semiconductor based devices. QCL-based PA sensors for NOx show a detection limit in the sub part-per-million range and are characterized by high selectivity and compact set-up. Electrochemically synthesized gold-nanoparticle FET sensors are able to monitor NOx in a concentration range from 50 to 200 parts per million and are suitable for miniaturization. Porphyrin-functionalized III-V semiconductor materials can be used for the fabrication of a reliable NOx sensor platform characterized by high conductivity, corrosion resistance, and strong surface state coupling. PMID:22412315

  7. Peroxynitrite formation in nitric oxide-exposed submitochondrial particles: detection, oxidative damage and catalytic removal by Mn-porphyrins.

    Science.gov (United States)

    Valez, Valeria; Cassina, Adriana; Batinic-Haberle, Ines; Kalyanaraman, Balaraman; Ferrer-Sueta, Gerardo; Radi, Rafael

    2013-01-01

    Peroxynitrite (ONOO(-)) formation in mitochondria may be favored due to the constant supply of superoxide radical (O(2)(∙-)) by the electron transport chain plus the facile diffusion of nitric oxide ((∙)NO) to this organelle. Herein, a model system of submitochondrial particles (SMP) in the presence of succinate plus the respiratory inhibitor antimycin A (to increase O(2)(∙-) rates) and the (∙)NO-donor NOC-7 was studied to directly establish and quantitate peroxynitrite by a multiplicity of methods including chemiluminescence, fluorescence and immunochemical analysis. While all the tested probes revealed peroxynitrite at near stoichiometric levels with respect to its precursor radicals, coumarin boronic acid (a probe that directly reacts with peroxynitrite) had the more straightforward oxidation profile from O(2)(∙-)-forming SMP as a function of the (∙)NO flux. Interestingly, immunospintrapping studies verified protein radical generation in SMP by peroxynitrite. Substrate-supplemented SMP also reduced Mn(III)porphyrins (MnP) to Mn(II)P under physiologically-relevant oxygen levels (3-30 μM); then, Mn(II)P were capable to reduce peroxynitrite and protect SMP from the inhibition of complex I-dependent oxygen consumption and protein radical formation and nitration of membranes. The data directly support the formation of peroxynitrite in mitochondria and demonstrate that MnP can undergo a catalytic redox cycle to neutralize peroxynitrite-dependent mitochondrial oxidative damage. Copyright © 2012 Elsevier Inc. All rights reserved.

  8. Effects of NOX Storage Component on Ammonia Formation in TWC for Passive SCR NOX Control in Lean Gasoline Engines

    Energy Technology Data Exchange (ETDEWEB)

    Prikhodko, Vitaly Y. [ORNL; Pihl, Josh A. [ORNL; Toops, Todd J. [ORNL; Parks, II, James E. [ORNL

    2018-04-01

    A prototype three-way catalyst (TWC) with NOX storage component was evaluated for ammonia (NH3) generation on a 2.0-liter BMW lean burn gasoline direct injection engine as a component in a passive ammonia selective catalytic reduction (SCR) system. The passive NH3 SCR system is a potential approach for controlling nitrogen oxides (NOX) emissions from lean burn gasoline engines. In this system, NH3 is generated over a close-coupled TWC during periodic slightly-rich engine operation and subsequently stored on an underfloor SCR catalyst. Upon switching to lean, NOX passes through the TWC and is reduced by the stored NH3 on the SCR catalyst. Adding a NOX storage component to a TWC provides two benefits in the context of a passive SCR system: (1) enabling longer lean operation by storing NOX upstream and preserving NH3 inventory on the downstream SCR catalyst; and (2) increasing the quantity and rate of NH3 production during rich operation. Since the fuel penalty associated with passive SCR NOX control depends on the fraction of time that the engine is running rich rather than lean, both benefits (longer lean times and shorter rich times achieved via improved NH3 production) will decrease the passive SCR fuel penalty. However, these benefits are primarily realized at low to moderate temperatures (300-500 °C), where the NOX storage component is able to store NOX, with little to no benefit at higher temperatures (>500 °C), where NOX storage is no longer effective. This study discusses engine parameters and control strategies affecting the NH3 generation over a TWC with NOX storage component.

  9. The Use of Amine Reclaimer Wastes as a NOx Reduction Agent

    DEFF Research Database (Denmark)

    Botheju, Deshai; Glarborg, Peter; Tokheim, Lars-Andre

    2013-01-01

    scale experimental trials carried out in this study using ARW and pure monoethanolamine (MEA) confirmed the possibility of utilizing ARW as a potential reagent for the selective non-catalytic reduction (SNCR) of NOx in combustion flue gases. Even though the effectiveness of ARW is lower than...... that of aqueous ammonia, i.e. the most common SNCR chemical reagent used in industry (above 60% NOx reduction efficiency), ARW is nonetheless shown to possess valuable SNCR qualities (at least 20% NOx reduction efficiency) considering its availability as a waste product which has to be safely disposed. A series...... generated in CCS, and emission of NOx a class of highly active greenhouse gases....

  10. Consideration of the Role of Plasma in a Plasma-Coupled Selective Catalytic Reduction of Nitrogen Oxides with a Hydrocarbon Reducing Agent

    Directory of Open Access Journals (Sweden)

    Byeong Ju Lee

    2017-10-01

    Full Text Available The purpose of this study is to explain how plasma improves the performance of selective catalytic reduction (SCR of nitrogen oxides (NOx with a hydrocarbon reducing agent. In the plasma-coupled SCR process, NOx reduction was performed with n-heptane as a reducing agent over Ag/γ-Al2O3 as a catalyst. We found that the plasma decomposes n-heptane into several oxygen-containing products such as acetaldehyde, propionaldehyde and butyraldehyde, which are more reactive than the parent molecule n-heptane in the SCR process. Separate sets of experiments using acetaldehyde, propionaldehyde and butyraldehyde, one by one, as a reductant in the absence of plasma, have clearly shown that the presence of these partially oxidized compounds greatly enhanced the NOx conversion. The higher the discharge voltage, the more the amounts of such partially oxidized products. The oxidative species produced by the plasma easily converted NO into NO2, but the increase of the NO2 fraction was found to decrease the NOx conversion. Consequently, it can be concluded that the main role of plasma in the SCR process is to produce partially oxidized compounds (aldehydes, having better reducing power. The catalyst-alone NOx removal efficiency with n-heptane at 250 °C was measured to be less than 8%, but it increased to 99% in the presence of acetaldehyde at the same temperature. The NOx removal efficiency with the aldehyde reducing agent was higher as the number of carbons in the aldehyde was more; for example, the NOx removal efficiencies at 200 °C with butyraldehyde, propionaldehyde and acetaldehyde were measured to be 83.5%, 58.0% and 61.5%, respectively, which were far above the value (3% obtained with n-heptane.

  11. NOx Control Options and Integration for US Coal Fired Boilers

    Energy Technology Data Exchange (ETDEWEB)

    Mike Bockelie; Kevin Davis; Temi Linjewile; Connie Senior; Eric Eddings; Kevin Whitty; Larry Baxter; Calvin Bartholomew; William Hecker; Stan Harding; Robert Hurt

    2003-12-31

    This is the fourteenth Quarterly Technical Report for DOE Cooperative Agreement No: DEFC26-00NT40753. The goal of the project is to develop cost effective analysis tools and techniques for demonstrating and evaluating low NOx control strategies and their possible impact on boiler performance for boilers firing US coals. The Electric Power Research Institute (EPRI) is providing co-funding for this program. Using the initial CFD baseline modeling of the Gavin Station and the plant corrosion maps, six boiler locations for the corrosion probes were identified and access ports have been installed. Preliminary corrosion data obtained appear consistent and believable. In situ, spectroscopic experiments at BYU reported in part last quarter were completed. New reactor tubes have been made for BYU's CCR that allow for testing smaller amounts of catalyst and thus increasing space velocity; monolith catalysts have been cut and a small reactor that can accommodate these pieces for testing is in its final stages of construction. A poisoning study on Ca-poisoned catalysts was begun this quarter. A possible site for a biomass co-firing test of the slipstream reactor was visited this quarter. The slipstream reactor at Rockport required repair and refurbishment, and will be re-started in the next quarter. This report describes the final results of an experimental project at Brown University on the fundamentals of ammonia / fly ash interactions with relevance to the operation of advanced NOx control technologies such as selective catalytic reduction. The Brown task focused on the measurement of ammonia adsorption isotherms on commercial fly ash samples subjected to a variety of treatments and on the chemistry of dry and semi-dry ammonia removal processes.

  12. Enhanced Combustion Low NOx Pulverized Coal Burner

    Energy Technology Data Exchange (ETDEWEB)

    David Towle; Richard Donais; Todd Hellewell; Robert Lewis; Robert Schrecengost

    2007-06-30

    For more than two decades, Alstom Power Inc. (Alstom) has developed a range of low cost, infurnace technologies for NOx emissions control for the domestic U.S. pulverized coal fired boiler market. This includes Alstom's internally developed TFS 2000{trademark} firing system, and various enhancements to it developed in concert with the U.S. Department of Energy. As of the date of this report, more than 270 units representing approximately 80,000 MWe of domestic coal fired capacity have been retrofit with Alstom low NOx technology. Best of class emissions range from 0.18 lb/MMBtu for bituminous coal to 0.10 lb/MMBtu for subbituminous coal, with typical levels at 0.24 lb/MMBtu and 0.13 lb/MMBtu, respectively. Despite these gains, NOx emissions limits in the U.S. continue to ratchet down for new and existing boiler equipment. On March 10, 2005, the Environmental Protection Agency (EPA) announced the Clean Air Interstate Rule (CAIR). CAIR requires 25 Eastern states to reduce NOx emissions from the power generation sector by 1.7 million tons in 2009 and 2.0 million tons by 2015. Low cost solutions to meet such regulations, and in particular those that can avoid the need for a costly selective catalytic reduction system (SCR), provide a strong incentive to continue to improve low NOx firing system technology to meet current and anticipated NOx control regulations. The overall objective of the work is to develop an enhanced combustion, low NOx pulverized coal burner, which, when integrated with Alstom's state-of-the-art, globally air staged low NOx firing systems will provide a means to achieve: Less than 0.15 lb/MMBtu NOx emissions when firing a high volatile Eastern or Western bituminous coal, Less than 0.10 lb/MMBtu NOx emissions when firing a subbituminous coal, NOx reduction costs at least 25% lower than the costs of an SCR, Validation of the NOx control technology developed through large (15 MWt) pilot scale demonstration, and Documentation required for

  13. Decreased NOx emissions by use of selective catalytic reduction on a gas turbine in the food-processing sector; Reduction des emissions de NOx par l'application de la reduction catalytique selective a une turbine a gaz dans le secteur de l'agro-alimentaire

    Energy Technology Data Exchange (ETDEWEB)

    Van Esch, F.A.J. [Cerestar Benelux B.V., Sas van Gent (Netherlands)

    2001-07-01

    Cerestar is a company of Eridania Beghin-Say, and manufactures starches and starch derivatives. Its activities are controlled from Paris, France, with sales offices and production facilities located throughout the world. Eridania Beghin-Say is one of the leading companies in the processing of agricultural raw materials into food products such as sugar, starch and derivatives of starch, oils, vegetable proteins and lecithin, consumer products and animal feed. The largest Cerestar plant in Europe is located in Sas van Gent, The Netherlands. Different starches, starch derivatives and glucoses are produced from the raw materials corn and wheat. Cerestar has own cogeneration plants for the production of steam and electricity. This year, the capacity of the plant was doubled, by the construction of a new wheat plant. Together with the wheat plant, a third cogeneration plant was built, with NOx emissions much below the legal limits. (authors)

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

    Science.gov (United States)

    Steele, Robert C; Edmonds, Ryan G; Williams, Joseph T; Baldwin, Stephen P

    2012-11-20

    A trapped vortex combustor. The trapped vortex combustor is configured for receiving a lean premixed gaseous fuel and oxidant stream, where the fuel includes hydrogen gas. The trapped vortex combustor is configured to receive the lean premixed fuel and oxidant stream at a velocity which significantly exceeds combustion flame speed in a selected lean premixed fuel and oxidant mixture. The combustor is configured to operate at relatively high bulk fluid velocities while maintaining stable combustion, and low NOx emissions. The combustor is useful in gas turbines in a process of burning synfuels, as it offers the opportunity to avoid use of diluent gas to reduce combustion temperatures. The combustor also offers the possibility of avoiding the use of selected catalytic reaction units for removal of oxides of nitrogen from combustion gases exiting a gas turbine.

  15. Silver ion mediated shape control of platinum nanoparticles: Removal of silver by selective etching leads to increased catalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Grass, Michael E.; Yue, Yao; Habas, Susan E.; Rioux, Robert M.; Teall, Chelsea I.; Somorjai, G.A.

    2008-01-09

    A procedure has been developed for the selective etching of Ag from Pt nanoparticles of well-defined shape, resulting in the formation of elementally-pure Pt cubes, cuboctahedra, or octahedra, with a largest vertex-to-vertex distance of {approx}9.5 nm from Ag-modified Pt nanoparticles. A nitric acid etching process was applied Pt nanoparticles supported on mesoporous silica, as well as nanoparticles dispersed in aqueous solution. The characterization of the silica-supported particles by XRD, TEM, and N{sub 2} adsorption measurements demonstrated that the structure of the nanoparticles and the mesoporous support remained conserved during etching in concentrated nitric acid. Both elemental analysis and ethylene hydrogenation indicated etching of Ag is only effective when [HNO{sub 3}] {ge} 7 M; below this concentration, the removal of Ag is only {approx}10%. Ethylene hydrogenation activity increased by four orders of magnitude after the etching of Pt octahedra that contained the highest fraction of silver. High-resolution transmission electron microscopy of the unsupported particles after etching demonstrated that etching does not alter the surface structure of the Pt nanoparticles. High [HNO{sub 3}] led to the decomposition of the capping agent, polyvinylpyrollidone (PVP); infrared spectroscopy confirmed that many decomposition products were present on the surface during etching, including carbon monoxide.

  16. System and method for selective catalytic reduction of nitrogen oxides in combustion exhaust gases

    Science.gov (United States)

    Sobolevskiy, Anatoly; Rossin, Joseph A

    2014-04-08

    A multi-stage selective catalytic reduction (SCR) unit (32) provides efficient reduction of NOx and other pollutants from about 50-550.degree. C. in a power plant (19). Hydrogen (24) and ammonia (29) are variably supplied to the SCR unit depending on temperature. An upstream portion (34) of the SCR unit catalyzes NOx+NH.sub.3 reactions above about 200.degree. C. A downstream portion (36) catalyzes NOx+H.sub.2 reactions below about 260.degree. C., and catalyzes oxidation of NH.sub.3, CO, and VOCs with oxygen in the exhaust above about 200.degree. C., efficiently removing NOx and other pollutants over a range of conditions with low slippage of NH.sub.3. An ammonia synthesis unit (28) may be connected to the SCR unit to provide NH.sub.3 as needed, avoiding transport and storage of ammonia or urea at the site. A carbonaceous gasification plant (18) on site may supply hydrogen and nitrogen to the ammonia synthesis unit, and hydrogen to the SCR unit.

  17. NOX2-mediated arterial dysfunction in smokers: acute effect of dark chocolate.

    Science.gov (United States)

    Loffredo, Lorenzo; Carnevale, Roberto; Perri, Ludovica; Catasca, Elisa; Augelletti, Teresa; Cangemi, Roberto; Albanese, Fabiana; Piccheri, Cristina; Nocella, Cristina; Pignatelli, Pasquale; Violi, Francesco

    2011-11-01

    Cocoa seems to exert artery dilatation via oxidative stress inhibition but the mechanism is still unclear. To investigate whether in smokers, dark chocolate elicits artery dilatation via down-regulation of NOX2, the catalytic core of NADPH oxidase. Flow-mediated dilatation (FMD), oxidative stress (as assessed by urinary isoprostanes excretion), nitric oxide generation (as assessed by serum levels of nitrite/nitrate (NOx)), NOX2 activity (as assessed by blood levels of soluble NOX2 derived peptide (sNOX2-dp)) and serum epicatechin were studied in 20 smokers and 20 healthy subjects (HS) in a crossover, single-blind study. Patients were randomly allocated to 40 g dark chocolate (>85% cocoa) or 40 g of milk chocolate (≤35% cocoa). FMD, urinary isoprostanes, NOx and sNOX2-dp were assessed at baseline and 2 h after chocolate ingestion. Smokers had lower FMD and NOx and higher sNOX2-dp compared to HS. After dark chocolate intake, urinary isoprostanes and sNOX2-dp significantly decreased and FMD and NOx significantly increased in smokers but not in HS. No changes of the above variables were observed after milk chocolate intake. Multiple linear regression analysis showed that in smokers the only independent predictive variable associated with a change in FMD was a change in sNOX2-dp. Serum epicatechin increased in either group only after dark chocolate intake, reaching values higher than 0.1 μM. Platelets from smokers (n=5), but not from HS (n=5), showed lower p47(phox) translocation to platelet membrane and higher NOx when incubated with 0.1-10 μM epicatechin. Results suggest that in smokers, cocoa enhances artery dilatation by lowering of NOX2 activation.

  18. Molecular evolution of the reactive oxygen-generating NADPH oxidase (Nox/Duox family of enzymes

    Directory of Open Access Journals (Sweden)

    Lambeth J David

    2007-07-01

    Full Text Available Abstract Background NADPH-oxidases (Nox and the related Dual oxidases (Duox play varied biological and pathological roles via regulated generation of reactive oxygen species (ROS. Members of the Nox/Duox family have been identified in a wide variety of organisms, including mammals, nematodes, fruit fly, green plants, fungi, and slime molds; however, little is known about the molecular evolutionary history of these enzymes. Results We assembled and analyzed the deduced amino acid sequences of 101 Nox/Duox orthologs from 25 species, including vertebrates, urochordates, echinoderms, insects, nematodes, fungi, slime mold amoeba, alga and plants. In contrast to ROS defense enzymes, such as superoxide dismutase and catalase that are present in prokaryotes, ROS-generating Nox/Duox orthologs only appeared later in evolution. Molecular taxonomy revealed seven distinct subfamilies of Noxes and Duoxes. The calcium-regulated orthologs representing 4 subfamilies diverged early and are the most widely distributed in biology. Subunit-regulated Noxes represent a second major subdivision, and appeared first in fungi and amoeba. Nox5 was lost in rodents, and Nox3, which functions in the inner ear in gravity perception, emerged the most recently, corresponding to full-time adaptation of vertebrates to land. The sea urchin Strongylocentrotus purpuratus possesses the earliest Nox2 co-ortholog of vertebrate Nox1, 2, and 3, while Nox4 first appeared somewhat later in urochordates. Comparison of evolutionary substitution rates demonstrates that Nox2, the regulatory subunits p47phox and p67phox, and Duox are more stringently conserved in vertebrates than other Noxes and Nox regulatory subunits. Amino acid sequence comparisons identified key catalytic or regulatory regions, as 68 residues were highly conserved among all Nox/Duox orthologs, and 14 of these were identical with those mutated in Nox2 in variants of X-linked chronic granulomatous disease. In addition to

  19. Low Temperature Catalyst for NH3 Removal

    Science.gov (United States)

    Monje, Oscar; Melendez, Orlando

    2013-01-01

    Air revitalization technologies maintain a safe atmosphere inside spacecraft by the removal of C02, ammonia (NH3), and trace contaminants. NH3 onboard the International Space Station (ISS) is produced by crew metabolism, payloads, or during an accidental release of thermal control refrigerant. Currently, the ISS relies on removing NH3 via humidity condensate and the crew wears hooded respirators during emergencies. A different approach to cabin NH3 removal is to use selective catalytic oxidation (SCO), which builds on thermal catalytic oxidation concepts that could be incorporated into the existing TCCS process equipment architecture on ISS. A low temperature platinum-based catalyst (LTP-Catalyst) developed at KSC was used for converting NH3 to H20 and N2 gas by SCO. The challenge of implementing SCO is to reduce formation of undesirable byproducts like NOx (N20 and NO). Gas mixture analysis was conducted using FTIR spectrometry in the Regenerable VOC Control System (RVCS) Testbed. The RVCS was modified by adding a 66 L semi-sealed chamber, and a custom NH3 generator. The effect of temperature on NH3 removal using the LTP-Catalyst was examined. A suitable temperature was found where NH3 removal did not produce toxic NO, (NO, N02) and N20 formation was reduced.

  20. Impact of FCC regenerator design in the NOx emissions

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Hugo Borges; Sandes, Emanuel Freire; Gilbert, William Richard; Roncolatto, Rodolfo Eugenio; Gobbo, Rodrigo; Casavechia, Luiz Carlos; Candido, William Victor Carlos [Petroleo Brasileiro S.A. (PETROBRAS), Rio de Janeiro, RJ (Brazil); Bridi, Patricia Elaine [Possebon Engenharia, Sao Mateus do Sul, PR (Brazil)

    2012-07-01

    Fluid Catalytic Cracking (FCC) is the main point source of NOx in the refinery and it is responsible for at least 20% of the total NOx emissions from the refineries. The thermal NOx formation in the FCC regenerator is negligible. However, half of the feed nitrogen is converted to coke, and is burned in the regenerator. The majority of coke nitrogen is reduced to N2 and less than 10% is converted to NOx. This number may vary significantly with the oxygen excess in the flue gas and other operational conditions. With the purpose of evaluating the impact of different regenerator designs in NOx formation, several tests were carried out in the PETROBRAS FCC prototype unit. The test unit is equipped with adiabatic insulation and a CO boiler, allowing it to reproduce the heat balance of a commercial FCC and to operate either in full combustion or partial combustion. Two different designs of FCC regenerators were evaluated: single stage regenerator (the existing configuration) and two stage regenerator, with the catalyst bed divided into two sections by a structured packing baffle. It was observed in the tests that the combustion regime had a very strong effect on NOx formation. In full combustion, the effect of the FCC operating variables: excess oxygen, combustion promoter content in catalyst and regenerator design could be identified. The two stage configuration was capable of decreasing NOx emissions by 30%. In partial combustion, the effect of the CO-boiler variables on NOx emissions was overwhelming, but the use of the structured packing baffle was able to improve the catalyst regeneration.(author)

  1. Oxidation of elemental mercury by modified spent TiO2-based SCR-DeNOx catalysts in simulated coal-fired flue gas.

    Science.gov (United States)

    Zhao, Lingkui; Li, Caiting; Zhang, Xunan; Zeng, Guangming; Zhang, Jie; Xie, Yin'e

    2016-01-01

    In order to reduce the costs, the recycle of spent TiO2-based SCR-DeNOx catalysts were employed as a potential catalytic support material for elemental mercury (Hg(0)) oxidation in simulated coal-fired flue gas. The catalytic mechanism for simultaneous removal of Hg(0) and NO was also investigated. The catalysts were characterized by Brunauer-Emmett-Teller (BET), scanning electron microscope (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) method. Results indicated that spent TiO2-based SCR-DeNOx catalyst supported Ce-Mn mixed oxides catalyst (CeMn/SCR1) was highly active for Hg(0) oxidation at low temperatures. The Ce1.00Mn/SCR1 performed the best catalytic activities, and approximately 92.80% mercury oxidation efficiency was obtained at 150 °C. The inhibition effect of NH3 on Hg(0) oxidation was confirmed in that NH3 consumed the surface oxygen. Moreover, H2O inhibited Hg(0) oxidation while SO2 had a promotional effect with the aid of O2. The XPS results illustrated that the surface oxygen was responsible for Hg(0) oxidation and NO conversion. Besides, the Hg(0) oxidation and NO conversion were thought to be aided by synergistic effect between the manganese and cerium oxides.

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

    Science.gov (United States)

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

    2016-05-05

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

  3. Deactivation-resistant catalyst for selective catalyst reduction of NOx

    DEFF Research Database (Denmark)

    2011-01-01

    The present invention relates to a catalyst for selective catalytic reduction of NOx in alkali metal containing flue gas using ammonia as reductant, the catalyst comprising a surface with catalytically active sites, wherein the surface is at least partly coated with a coating comprising at least...... one metal oxide. In another aspect the present invention relates to the use of said catalyst and to a method of producing said catalyst. In addition, the present invention relates to a method of treating an catalyst for conferring thereon an improved resistance to alkali poisoning....

  4. Modeling of NOx Destruction Options for INEEL Sodium-Bearing Waste Vitrification

    Energy Technology Data Exchange (ETDEWEB)

    Wood, Richard Arthur

    2001-09-01

    Off-gas NOx concentrations in the range of 1-5 mol% are expected as a result of the proposed vitrification of sodium-bearing waste at the Idaho National Engineering and Environmental Laboratory. An existing kinetic model for staged combustion (originally developed for NOx abatement from the calcination process) was updated for application to vitrification offgas. In addition, two new kinetic models were developed to assess the feasibility of using selective non-catalytic reduction (SNCR) or high-temperature alone for NOx abatement. Each of the models was developed using the Chemkin code. Results indicate that SNCR is a viable option, reducing NOx levels to below 1000 ppmv. In addition, SNCR may be capable of simultaneously reducing CO emissions to below 100 ppmv. Results for using high-temperature alone were not as promising, indicating that a minimum NOx concentration of 3950 ppmv is achievable at 3344°F.

  5. Catalytic distillation process

    Science.gov (United States)

    Smith, L.A. Jr.

    1982-06-22

    A method is described for conducting chemical reactions and fractionation of the reaction mixture comprising feeding reactants to a distillation column reactor into a feed zone and concurrently contacting the reactants with a fixed bed catalytic packing to concurrently carry out the reaction and fractionate the reaction mixture. For example, a method for preparing methyl tertiary butyl ether in high purity from a mixed feed stream of isobutene and normal butene comprising feeding the mixed feed stream to a distillation column reactor into a feed zone at the lower end of a distillation reaction zone, and methanol into the upper end of said distillation reaction zone, which is packed with a properly supported cationic ion exchange resin, contacting the C[sub 4] feed and methanol with the catalytic distillation packing to react methanol and isobutene, and concurrently fractionating the ether from the column below the catalytic zone and removing normal butene overhead above the catalytic zone.

  6. LOW NOX BURNER DEVELOPMENT

    Energy Technology Data Exchange (ETDEWEB)

    KRISHNA,C.R.; BUTCHER,T.

    2004-09-30

    The objective of the task is to develop concepts for ultra low NOx burners. One approach that has been tested previously uses internal recirculation of hot gases and the objective was to how to implement variable recirculation rates during burner operation. The second approach was to use fuel oil aerosolization (vaporization) and combustion in a porous medium in a manner similar to gas-fired radiant burners. This task is trying the second approach with the use of a somewhat novel, prototype system for aerosolization of the liquid fuel.

  7. A hybrid plasma-chemical system for high-NOx flue gas treatment

    Science.gov (United States)

    Chmielewski, Andrzej G.; Zwolińska, Ewa; Licki, Janusz; Sun, Yongxia; Zimek, Zbigniew; Bułka, Sylwester

    2018-03-01

    The reduction of high concentrations of NOx and SO2 from simulated flue gas has been studied. Our aim was to optimise energy consumption for NOx and SO2 removal from off-gases from a diesel generator using heavy fuel oil. A hybrid process: electron beam (EB) plasma and wet scrubber has been applied. A much higher efficiency of NOx and SO2 removal was achieved in comparison to dry, ammonia free, electron beam flue gas treatment (EBFGT). A recorded removal from a concentration of 1500 ppm NOx reached 49% at a low dose of 6.5 kGy, while only 2% NOx was removed at the same dose if EB only was applied. For SO2, removal efficiency at a dose of 6.5 kGy increased from 15% (EB only) to 84% when sea water was used as a wet scrubber agent for 700 ppm SO2. The results of this study indicate that EB combined with wet scrubber is a very promising technology to be applied for removal of high concentrations of NOx and SO2 emitted from diesel engines operated e.g. on cargo ships, which are the main sources of SO2 and NOx pollution along their navigation routes.

  8. Catalytic Combustor for Fuel-Flexible Turbine

    Energy Technology Data Exchange (ETDEWEB)

    W. R. Laster; E. Anoshkina

    2008-01-31

    Under the sponsorship of the U. S. Department of Energy's National Energy Technology Laboratory, Siemens Westinghouse has conducted a three-year program to develop an ultra low NOx, fuel flexible catalytic combustor for gas turbine application in IGCC. The program is defined in three phases: Phase 1 - Implementation Plan, Phase 2 - Validation Testing and Phase 3 - Field Testing. Both Phase 1 and Phase 2 of the program have been completed. In IGCC power plants, the gas turbine must be capable of operating on syngas as a primary fuel and an available back-up fuel such as natural gas. In this program the Rich Catalytic Lean (RCLTM) technology is being developed as an ultra low NOx combustor. In this concept, ultra low NOx is achieved by stabilizing a lean premix combustion process by using a catalytic reactor to oxidize a portion of the fuel, increasing the temperature of fuel/air mixture prior to the main combustion zone. In Phase 1, the feasibility of the catalytic concept for syngas application has been evaluated and the key technology issues identified. In Phase II the technology necessary for the application of the catalytic concept to IGCC fuels was developed through detailed design and subscale testing. Phase III (currently not funded) will consist of full-scale combustor basket testing on natural gas and syngas.

  9. Catalytic Combustor for Fuel-Flexible Turbine

    Energy Technology Data Exchange (ETDEWEB)

    Laster, W. R.; Anoshkina, E.

    2008-01-31

    Under the sponsorship of the U. S. Department of Energy’s National Energy Technology Laboratory, Siemens Westinghouse has conducted a three-year program to develop an ultra low NOx, fuel flexible catalytic combustor for gas turbine application in IGCC. The program is defined in three phases: Phase 1- Implementation Plan, Phase 2- Validation Testing and Phase 3 – Field Testing. Both Phase 1 and Phase 2 of the program have been completed. In IGCC power plants, the gas turbine must be capable of operating on syngas as a primary fuel and an available back-up fuel such as natural gas. In this program the Rich Catalytic Lean (RCLTM) technology is being developed as an ultra low NOx combustor. In this concept, ultra low NOx is achieved by stabilizing a lean premix combustion process by using a catalytic reactor to oxidize a portion of the fuel, increasing the temperature of fuel/air mixture prior to the main combustion zone. In Phase 1, the feasibility of the catalytic concept for syngas application has been evaluated and the key technology issues identified. In Phase II the technology necessary for the application of the catalytic concept to IGCC fuels was developed through detailed design and subscale testing. Phase III (currently not funded) will consist of full-scale combustor basket testing on natural gas and syngas.

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

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Pu-Xian

    2013-07-31

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

  11. Reduction of nitrogen oxides (NOx) by superalkalis

    Science.gov (United States)

    Srivastava, Ambrish Kumar

    2018-03-01

    NOx are major air pollutants, having negative impact on environment and consequently, human health. We propose here the single-electron reduction of NOx (x = 1, 2) using superalkalis. We study the interaction of NOx with FLi2, OLi3 and NLi4 superalkalis using density functional and single-point CCSD(T) calculations, which lead to stable superalkali-NOx ionic complexes with negatively charged NOx. This clearly reveals that the NOx can successfully be reduced to NOx- anion due to electron transfer from superalkalis. It has been also noticed that the size of superalkalis plays a crucial in the single-electron reduction of NOx.

  12. Electro Catalytic Oxidation (ECO) Operation

    Energy Technology Data Exchange (ETDEWEB)

    Morgan Jones

    2011-03-31

    The power industry in the United States is faced with meeting many new regulations to reduce a number of air pollutants including sulfur dioxide, nitrogen oxides, fine particulate matter, and mercury. With over 1,000 power plants in the US, this is a daunting task. In some cases, traditional pollution control technologies such as wet scrubbers and SCRs are not feasible. Powerspan's Electro-Catalytic Oxidation, or ECO{reg_sign} process combines four pollution control devices into a single integrated system that can be installed after a power plant's particulate control device. Besides achieving major reductions in emissions of sulfur dioxide (SO{sub 2}), nitrogen oxides (NOx), fine particulate matter (PM2.5) and mercury (Hg), ECO produces a highly marketable fertilizer, which can help offset the operating costs of the process system. Powerspan has been operating a 50-MW ECO commercial demonstration unit (CDU) at FirstEnergy Corp.'s R.E. Burger Plant near Shadyside, Ohio, since February 2004. In addition to the CDU, a test loop has been constructed beside the CDU to demonstrate higher NOx removal rates and test various scrubber packing types and wet ESP configurations. Furthermore, Powerspan has developed the ECO{reg_sign}{sub 2} technology, a regenerative process that uses a proprietary solvent to capture CO{sub 2} from flue gas. The CO{sub 2} capture takes place after the capture of NOx, SO{sub 2}, mercury, and fine particulate matter. Once the CO{sub 2} is captured, the proprietary solution is regenerated to release CO{sub 2} in a form that is ready for geological storage or beneficial use. Pilot scale testing of ECO{sub 2} began in early 2009 at FirstEnergy's Burger Plant. The ECO{sub 2} pilot unit is designed to process a 1-MW flue gas stream and produce 20 tons of CO{sub 2} per day, achieving a 90% CO{sub 2} capture rate. The ECO{sub 2} pilot program provided the opportunity to confirm process design and cost estimates, and prepare for large

  13. Genetic Targeting or Pharmacologic Inhibition of NADPH Oxidase Nox4 Provides Renoprotection in Long-Term Diabetic Nephropathy

    Science.gov (United States)

    Jha, Jay C.; Gray, Stephen P.; Barit, David; Okabe, Jun; El-Osta, Assam; Namikoshi, Tamehachi; Thallas-Bonke, Vicki; Wingler, Kirstin; Szyndralewiez, Cedric; Heitz, Freddy; Touyz, Rhian M.; Cooper, Mark E.; Schmidt, Harald H.H.W.

    2014-01-01

    Diabetic nephropathy may occur, in part, as a result of intrarenal oxidative stress. NADPH oxidases comprise the only known dedicated reactive oxygen species (ROS)–forming enzyme family. In the rodent kidney, three isoforms of the catalytic subunit of NADPH oxidase are expressed (Nox1, Nox2, and Nox4). Here we show that Nox4 is the main source of renal ROS in a mouse model of diabetic nephropathy induced by streptozotocin administration in ApoE−/− mice. Deletion of Nox4, but not of Nox1, resulted in renal protection from glomerular injury as evidenced by attenuated albuminuria, preserved structure, reduced glomerular accumulation of extracellular matrix proteins, attenuated glomerular macrophage infiltration, and reduced renal expression of monocyte chemoattractant protein-1 and NF-κB in streptozotocin-induced diabetic ApoE−/− mice. Importantly, administration of the most specific Nox1/4 inhibitor, GKT137831, replicated these renoprotective effects of Nox4 deletion. In human podocytes, silencing of the Nox4 gene resulted in reduced production of ROS and downregulation of proinflammatory and profibrotic markers that are implicated in diabetic nephropathy. Collectively, these results identify Nox4 as a key source of ROS responsible for kidney injury in diabetes and provide proof of principle for an innovative small molecule approach to treat and/or prevent chronic kidney failure. PMID:24511132

  14. NOX5 in Human Spermatozoa

    Science.gov (United States)

    Musset, Boris; Clark, Robert A.; DeCoursey, Thomas E.; Petheo, Gabor L.; Geiszt, Miklos; Chen, Yumin; Cornell, John E.; Eddy, Carlton A.; Brzyski, Robert G.; El Jamali, Amina

    2012-01-01

    Physiological and pathological processes in spermatozoa involve the production of reactive oxygen species (ROS), but the identity of the ROS-producing enzyme system(s) remains a matter of speculation. We provide the first evidence that NOX5 NADPH oxidase is expressed and functions in human spermatozoa. Immunofluorescence microscopy detected NOX5 protein in both the flagella/neck region and the acrosome. Functionally, spermatozoa exposed to calcium ionophore, phorbol ester, or H2O2 exhibited superoxide anion production, which was blocked by addition of superoxide dismutase, a Ca2+ chelator, or inhibitors of either flavoprotein oxidases (diphenylene iododonium) or NOX enzymes (GKT136901). Consistent with our previous overexpression studies, we found that H2O2-induced superoxide production by primary sperm cells was mediated by the non-receptor tyrosine kinase c-Abl. Moreover, the HV1 proton channel, which was recently implicated in spermatozoa motility, was required for optimal superoxide production by spermatozoa. Immunoprecipitation experiments suggested an interaction among NOX5, c-Abl, and HV1. H2O2 treatment increased the proportion of motile sperm in a NOX5-dependent manner. Statistical analyses showed a pH-dependent correlation between superoxide production and enhanced sperm motility. Collectively, our findings show that NOX5 is a major source of ROS in human spermatozoa and indicate a role for NOX5-dependent ROS generation in human spermatozoa motility. PMID:22291013

  15. NOx Control Options and Integration for US Coal Fired Boilers

    Energy Technology Data Exchange (ETDEWEB)

    Mike Bockelie; Kevin Davis; Temi Linjewile; Connie Senior; Eric Eddings; Kevin Whitty; Larry Baxter; Calvin Bartholomew; William Hecker; Stan Harding

    2004-06-30

    This is the sixteenth Quarterly Technical Report for DOE Cooperative Agreement No: DEFC26-00NT40753. The goal of the project is to develop cost effective analysis tools and techniques for demonstrating and evaluating low NOx control strategies and their possible impact on boiler performance for boilers firing US coals. The Electric Power Research Institute (EPRI) is providing co-funding for this program. During an unplanned outage, damage occurred to the electrochemical noise corrosion probes installed at the AEP Gavin plant; testing is expected to resume in August. The KEMCOP corrosion coupons were not affected by the unplanned outage; the coupons were removed and sent for analysis. BYU conducted a series of tests before the ISSR lab was relocated. Ammonia adsorption experiments provided clear evidence of the types of acidic sites present on catalyst surfaces. Data collected this quarter indicate that surface sulfation decreases Lewis acid site concentrations for all catalysts thus far studied, confirming that catalytic activity under commercial coal-based SCR conditions occurs primarily on Br{o}nsted acid sites and would be susceptible to basic impurities such as alkali and alkaline earth oxides, chlorides, and sulfates. SCR activity tests based on MS analysis showed that increasing sulfation generally increases NO reduction activity for both 0% and 1% vanadia catalysts. During this quarter, the slipstream reactor at Rockport operated for 720 hours on flue gas. Catalyst exposure time reached 4500 hours since installation. The reactor is out of service at the Rockport plant and plans are being made to move it to the Gadsden Plant. At Gadsden, modifications have begun in preparation for installation of the slipstream reactor next quarter.

  16. Monitoring of Basic Parameters for Selective Catalytic Reduction System Used in an Agricultural Tractor

    Directory of Open Access Journals (Sweden)

    Antonín Skřivánek

    2014-01-01

    Full Text Available Presented paper describes monitoring of basic parameters for selective catalytic reduction (SCR system used in an agricultural tractor. SCR systems are used to reduce emissions of nitrogen oxides (NOx produced by combustion of fuel. The usage of SCR catalytic converters entails certain disadvantages in the use of reducing agent and the necessity of suitable operating conditions to achieve optimum efficiency of the catalytic converter. This paper aims to predict consumption of AdBlue depending on the temperature of SCR catalytic converter, which reflects the engine load and monitoring the effectiveness of SCR catalytic converter when operating a tractor engine with a maximum dose of fuel. To fulfill those aims, the measurements have been performed on the Case Puma 185 CVX agricultural tractor. As the measurement results indicate, the lowest NOx emissions correspond to high consumption of AdBlue. Other studies imply that the catalytic converter operates at optimal operating temperature and with the highest efficiency of NOx emission reduction. The effectiveness of NOx emission reduction is thus affected not only by quantity of injected reagent but also by catalytic converter thermal load. Further measurement results indicate that the lowest amount of emissions of NOx (and the highest efficiency rate is achieved by catalytic converter in a range in which the engine operates with the highest engine efficiency.

  17. Urea-SCR Temperature Investigation for NOx Control of Diesel Engine

    Directory of Open Access Journals (Sweden)

    Asif Muhammad

    2015-01-01

    Full Text Available SCR (selective catalytic reduction system is continuously being analyzed by many researchers worldwide on various concerns due to the stringent nitrogen oxides (NOx emissions legislation for heavy-duty diesel engines. Urea-SCR includes AdBlue as urea source, which subsequently decomposes to NH3 (ammonia being the reducing agent. Reaction temperature is a key factor for the performance of urea-SCR system, as urea decomposition rate is sensitive to a specific temperature range. This particular study was directed to investigate the temperature of the SCR system in diesel engine with the objective to confirm that whether the appropriate temperature is attained for occurrence of urea based catalytic reduction or otherwise and how the system performs on the prescribed temperature range. Diesel engine fitted with urea-SCR exhaust system has been operated on European standard cycle for emission testing to monitor the temperature and corresponding nitrogen oxides (NOx values on specified points. Moreover, mathematical expressions for approximation of reaction temperature are also proposed which are derived by applying energy conservation principal and gas laws. Results of the investigation have shown that during the whole testing cycle system temperature has remained in the range where urea-SCR can take place with best optimum rate and the system performance on account of NOx reduction was exemplary as excellent NOx conversion rate is achieved. It has also been confirmed that selective catalytic reduction (SCR is the best suitable technology for automotive engine-out NOx control.

  18. 40 CFR 97.12 - Changing NOX authorized account representative and alternate NOX authorized account...

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Changing NOX authorized account representative and alternate NOX authorized account representative; changes in owners and operators. 97.12... (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS NOX Authorized Account...

  19. Sulfur Deactivation of NOx Storage Catalysts: A Multiscale Modeling Approach

    Directory of Open Access Journals (Sweden)

    Rankovic N.

    2013-09-01

    Full Text Available Lean NOx Trap (LNT catalysts, a promising solution for reducing the noxious nitrogen oxide emissions from the lean burn and Diesel engines, are technologically limited by the presence of sulfur in the exhaust gas stream. Sulfur stemming from both fuels and lubricating oils is oxidized during the combustion event and mainly exists as SOx (SO2 and SO3 in the exhaust. Sulfur oxides interact strongly with the NOx trapping material of a LNT to form thermodynamically favored sulfate species, consequently leading to the blockage of NOx sorption sites and altering the catalyst operation. Molecular and kinetic modeling represent a valuable tool for predicting system behavior and evaluating catalytic performances. The present paper demonstrates how fundamental ab initio calculations can be used as a valuable source for designing kinetic models developed in the IFP Exhaust library, intended for vehicle simulations. The concrete example we chose to illustrate our approach was SO3 adsorption on the model NOx storage material, BaO. SO3 adsorption was described for various sites (terraces, surface steps and kinks and bulk for a closer description of a real storage material. Additional rate and sensitivity analyses provided a deeper understanding of the poisoning phenomena.

  20. A broad spectrum catalytic system for removal of toxic organics from water by deep oxidation. Annual progress report, September 15, 1996 - September 14, 1997

    International Nuclear Information System (INIS)

    Sen, A.

    1997-01-01

    'During the first year, the palladium-catalyzed deep oxidation of toxic organics by dioxygen in aqueous solution was examined in some detail. The research performed has established the viability of the catalytic system to effect the deep (and complete) oxidation of a very wide range of organic substrates under mild conditions. One significant observation was that chemical warfare agent models containing phosphorus-carbon and sulfur-carbon bonds could be eliminated by using this procedure.'

  1. Optical and Electronic NO(x) Sensors for Applications in Mechatronics.

    Science.gov (United States)

    Di Franco, Cinzia; Elia, Angela; Spagnolo, Vincenzo; Scamarcio, Gaetano; Lugarà, Pietro Mario; Ieva, Eliana; Cioffi, Nicola; Torsi, Luisa; Bruno, Giovanni; Losurdo, Maria; Garcia, Michael A; Wolter, Scott D; Brown, April; Ricco, Mario

    2009-01-01

    Current production and emerging NO(x) sensors based on optical and nanomaterials technologies are reviewed. In view of their potential applications in mechatronics, we compared the performance of: i) Quantum cascade lasers (QCL) based photoacoustic (PA) systems; ii) gold nanoparticles as catalytically active materials in field-effect transistor (FET) sensors, and iii) functionalized III-V semiconductor based devices. QCL-based PA sensors for NO(x) show a detection limit in the sub part-per-million range and are characterized by high selectivity and compact set-up. Electrochemically synthesized gold-nanoparticle FET sensors are able to monitor NO(x) in a concentration range from 50 to 200 parts per million and are suitable for miniaturization. Porphyrin-functionalized III-V semiconductor materials can be used for the fabrication of a reliable NO(x) sensor platform characterized by high conductivity, corrosion resistance, and strong surface state coupling.

  2. Retrofit SCR system for NOx control from heavy-duty mining equipment

    International Nuclear Information System (INIS)

    Mannan, M.A.

    2009-01-01

    Diesel engines are used extensively in the mining industry and offer many advantages. However, particulate matter (PM) emissions and nitrogen oxide emissions (NOx) are among its disadvantages. A significant concern related to PM and NOx in an underground mine involves the use of diesel exhaust after treatment systems such as diesel particulate filters and selective catalytic reduction (SCR). This presentation discussed NOx and PM control and provided a description of an SCR system and examples of SCR retrofits. Options for NOx control were discussed and a case study involving the installation of an SCR retrofit system in an underground mine operated by Sifto Salt was also presented. The purpose of the case study was to identify cost effective retrofit solutions to lower nitrogen dioxide emissions from heavy-duty trucks operating in underground mines. The case study illustrated and presented the candidate vehicle, baseline emissions, a BlueMax SCR retrofit solution, and BlueMax installation. 1 tab., 6 figs.

  3. Nighttime NOx Chemistry in Coal-Fired Power Plant Plumes

    Science.gov (United States)

    Fibiger, D. L.; McDuffie, E. E.; Dube, W. P.; Veres, P. R.; Lopez-Hilfiker, F.; Lee, B. H.; Green, J. R.; Fiddler, M. N.; Ebben, C. J.; Sparks, T.; Weinheimer, A. J.; Montzka, D.; Campos, T. L.; Cohen, R. C.; Bililign, S.; Holloway, J. S.; Thornton, J. A.; Brown, S. S.

    2015-12-01

    Nitrogen oxides (NOx = NO + NO2) play a key role in atmospheric chemistry. During the day, they catalyze ozone (O3) production, while at night they can react to form nitric acid (HNO3) and nitryl chloride (ClNO2) and remove O3 from the atmosphere. These processes are well studied in the summer, but winter measurements are more limited. Coal-fired power plants are a major source of NOx to the atmosphere, making up approximately 30% of emissions in the US (epa.gov). NOx emissions can vary seasonally, as well as plant-to-plant, with important impacts on the details of the plume chemistry. In particular, due to inefficient plume dispersion, nighttime NOx emissions from power plants are held in concentrated plumes, where rates of mixing with ambient O3 have a strong influence on plume evolution. We will show results from the aircraft-based WINTER campaign over the northeastern United States, where several nighttime intercepts of power plant plumes were made. Several of these intercepts show complete O3 titration, which can have a large influence on NOx lifetime, and thus O3 production, in the plume. When power plant NO emissions exceed background O3 levels, O3 is completely consumed converting NO to NO2. In the presence of O3, NO2 will be oxidized to NO3, which will then react with NO2 to form N2O5, which can then form HNO3 and/or ClNO2 and, ultimately, remove NOx from the atmosphere or provide next-day oxidant sources. If there is no O3 present, however, no further chemistry can occur and NO and NO2 will be transported until mixing with sufficient O3 for higher oxidation products. Modeling results of plume development and mixing, which can tell us more about this transport, will also be presented.

  4. Nox1 downstream of 12-lipoxygenase controls cell proliferation but not cell spreading of colon cancer cells.

    Science.gov (United States)

    de Carvalho, Daniela D; Sadok, Amine; Bourgarel-Rey, Véronique; Gattacceca, Florence; Penel, Claude; Lehmann, Maxime; Kovacic, Hervé

    2008-04-15

    The catalytic subunit of the NADPH oxidase complex, Nox1 (homologue of gp91phox/Nox2), expressed mainly in intestinal epithelial and vascular smooth muscle cells, functions in innate immune defense and cell proliferation. The molecular mechanisms underlying these functions, however, are not completely understood. We measured Nox1-dependent O2- production during cell spreading on Collagen IV (Coll IV) in colon carcinoma cell lines. Knocking down Nox1 by shRNA, we showed that Nox1-dependent O2- production is activated during cell spreading after 4 hr of adhesion on Collagen IV. Nox1 activation during cell spreading relies on Rac1 activation and arachidonic metabolism. Our results showed that manoalide (a secreted phospholipase A2 inhibitor) and cinnamyl-3,4-dihydroxy-alpha-cyanocinnamate (a 12-lipoxygenase inhibitor) inhibit O2- production, cell spreading and cell proliferation in these colonic epithelial cells. 12-Lipoxygenase inhibition of ROS production and cell spreading can be reversed by adding 12-HETE, a 12-lipoxygenase product, supporting the specific effect observed with cinnamyl-3,4-dihydroxy-alpha-cyanocinnamate. In contrast, Nox1 shRNA and DPI (NADPH oxidase inhibitor) weakly affect cell spreading while inhibiting O2- production and cell proliferation. These results suggest that the 12-lipoxygenase pathway is upstream of Nox1 activation and controls cell spreading and proliferation, while Nox1 specifically affects cell proliferation.

  5. Plasma and catalyst for the oxidation of NOx

    DEFF Research Database (Denmark)

    Jögi, I.; Erme, K.; Levoll, E.

    2017-01-01

    The removal of NOx from the exhaust gases requires the oxidation of most abundant NO to NO2 or N2O5. The oxidation can be done by non-thermal plasma but the efficiency is limited due to the back-reaction of NO2 to NO by O radicals. Present contribution investigates the role of catalysts in the im......The removal of NOx from the exhaust gases requires the oxidation of most abundant NO to NO2 or N2O5. The oxidation can be done by non-thermal plasma but the efficiency is limited due to the back-reaction of NO2 to NO by O radicals. Present contribution investigates the role of catalysts...... in the improvement of oxidation efficiency based on the stationary and time-dependent studies of the NOx oxidation at different reactor configurations and experimental conditions. The plasma produced active oxygen species (O, O3) were shown to play an important role in the reactions taking place on the catalyst...... surfaces while the exact mechanism and extent of the effect depended on the reactor configuration. The effect of catalyst at different experimental conditions was quantitatively described with the aid of analytical lumped kinetic models derived for the NOx oxidation when the catalyst was directly...

  6. Adsorbent catalytic nanoparticles and methods of using the same

    Energy Technology Data Exchange (ETDEWEB)

    Slowing, Igor Ivan; Kandel, Kapil

    2017-01-31

    The present invention provides an adsorbent catalytic nanoparticle including a mesoporous silica nanoparticle having at least one adsorbent functional group bound thereto. The adsorbent catalytic nanoparticle also includes at least one catalytic material. In various embodiments, the present invention provides methods of using and making the adsorbent catalytic nanoparticles. In some examples, the adsorbent catalytic nanoparticles can be used to selectively remove fatty acids from feedstocks for biodiesel, and to hydrotreat the separated fatty acids.

  7. Sum frequency generation and catalytic reaction studies of the removal of the organic capping agents from Pt nanoparticles by UV-ozone treatment

    Energy Technology Data Exchange (ETDEWEB)

    Aliaga, Cesar; Park, Jeong Y.; Yamada, Yusuke; Lee, Hyun Sook; Tsung, Chia-Kuang; Yang, Peidong; Somorjai, Gabor A.

    2009-12-10

    We report the structure of the organic capping layers of platinum colloid nanoparticles and their removal by UV-ozone exposure. Sum frequency generation vibrational spectroscopy (SFGVS) studies identify the carbon-hydrogen stretching modes on poly(vinylpyrrolidone) (PVP) and tetradecyl tributylammonium bromide (TTAB)-capped platinum nanoparticles. We found that the UV-ozone treatment technique effectively removes the capping layer on the basis of several analytical measurements including SFGVS, X-ray photoelectron spectroscopy, and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). The overall shape of the nanoparticles was preserved after the removal of capping layers, as confirmed by transmission electron microscopy (TEM). SFGVS of ethylene hydrogenation on the clean platinum nanoparticles demonstrates the existence of ethylidyne and di-{sigma}-bonded species, indicating the similarity between single-crystal and nanoparticle systems.

  8. 40 CFR 52.2237 - NOX RACT and NOX conformity exemption.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 4 2010-07-01 2010-07-01 false NOX RACT and NOX conformity exemption... PROGRAMS (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS (CONTINUED) Tennessee § 52.2237 NOX RACT and NOX conformity exemption. Approval. EPA is approving the section 182(f) oxides of nitrogen...

  9. 40 CFR 97.188 - CAIR NOX allowance allocations to CAIR NOX opt-in units.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false CAIR NOX allowance allocations to CAIR NOX opt-in units. 97.188 Section 97.188 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS...

  10. 40 CFR 96.52 - NOX Allowance Tracking System responsibilities of NOX authorized account representative.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false NOX Allowance Tracking System responsibilities of NOX authorized account representative. 96.52 Section 96.52 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND...

  11. 40 CFR 96.188 - CAIR NOX allowance allocations to CAIR NOX opt-in units.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false CAIR NOX allowance allocations to CAIR NOX opt-in units. 96.188 Section 96.188 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS FOR...

  12. Pilot-Scale Demonstration of ALTA for NOx Control in Pulverized Coal-Fired Boilers

    Energy Technology Data Exchange (ETDEWEB)

    Andrew Fry; Devin Davis; Marc Cremer; Bradley Adams

    2008-04-30

    This report describes computational fluid dynamics (CFD) modeling and pilot-scale testing conducted to demonstrate the ability of the Advanced Layered Technology Approach (ALTA) to reduce NO{sub x} emissions in a pulverized coal (PC) boiler. Testing specifically focused on characterizing NO{sub x} behavior with deep burner staging combined with Rich Reagent Injection (RRI). Tests were performed in a 4 MBtu/hr pilot-scale furnace at the University of Utah. Reaction Engineering International (REI) led the project team which included the University of Utah and Combustion Components Associates (CCA). Deep burner staging and RRI, combined with selective non-catalytic reduction (SNCR), make up the Advanced Layered Technology Approach (ALTA) for NO{sub x} reduction. The application of ALTA in a PC environment requires homogenization and rapid reaction of post-burner combustion gases and has not been successfully demonstrated in the past. Operation of the existing low-NO{sub x} burner and design and operation of an application specific ALTA burner was guided by CFD modeling conducted by REI. Parametric pilot-scale testing proved the chemistry of RRI in a PC environment with a NOx reduction of 79% at long residence times and high baseline NOx rate. At representative particle residence times, typical operation of the dual-register low-NO{sub x} burner provided an environment that was unsuitable for NO{sub x} reduction by RRI, showing no NOx reduction. With RRI, the ALTA burner was able to produce NO{sub x} emissions 20% lower than the low-NO{sub x} burner, 76 ppmv vs. 94 ppmv, at a burner stoichiometric ratio (BSR) of 0.7 and a normalized stoichiometric ratio (NSR) of 2.0. CFD modeling was used to investigate the application of RRI for NO{sub x} control on a 180 MW{sub e} wall-fired, PC boiler. A NO{sub x} reduction of 37% from baseline (normal operation) was predicted using ALTA burners with RRI to produce a NO{sub x} emission rate of 0.185 lb/MBtu at the horizontal nose of

  13. Methane-benzene binary mixture destruction in a reverse flow catalytic reactor

    International Nuclear Information System (INIS)

    Geng, Chen; Yong, Chi; Chunpeng, Pan; Yan, Jian-hua; Ni, Ming-Jian

    2010-01-01

    A reverse flow reactor (RFR) is a packed catalytic bed reactor in which feed flow direction is periodically reversed. When an exothermic catalytic combustion is conducted in a RFR, a hot zone is trapped in the center while both ends of the reactor act as regenerative heat exchanger. This enables an auto thermal operation at high temperatures even for feeds having a low adiabatic temperature rise. These features make RFR highly competitive for VOCs combustion. An experimental study of binary mixture purification in bench scale reverse flow reactor, with an inner diameter of 60 mm, has been carried out. Methane and benzene are chosen due to their different properties. The ignition temperature of methane is higher than any other hydrocarbons and benzene is widely used as solvent in industry. With periodic reversal feed, auto thermal catalytic combustion of very lean binary mixture can be achieved. When peak temperature in the hot zone reaches about 550 degree Celsius, both methane and benzene are well removed and little NOx or no other secondary pollutants are detected. The influence of several operation parameters, such as gas velocity, cycle period and methane-to-benzene ratio are discussed. A mathematical model has been developed and solved using a FORTRAN code, good correspondence being observed between both approaches. This provides a solution if VOC concentration in the contaminated air is too low to maintain an auto thermal operation, while natural gas (which is mainly methane) can be added as auxiliary fuel. (author)

  14. Real world NOx emissions of Euro V vehicles

    Energy Technology Data Exchange (ETDEWEB)

    Verbeek, R.; Vonk, W.A.; Verbeek, R.P.; Dekker, H. [TNO Science and Industry, Delft (Netherlands)

    2010-11-15

    In the past decade, vehicle emissions have been reduced substantially as a result of the European emission legislation. Air quality problems are still present, however, in particular in urban areas where local authorities have difficulty meeting European limits regarding air quality (mainly NO2). Therefore, the emission performance of vehicles under urban conditions is of increasing importance for air quality improvement in cities. In this context, TNO was commissioned by the Dutch Ministry of Environment (VROM) to investigate the real-world NOx emissions of Euro V trucks and buses during the past two years. The investigation has shown that, in general, there is a large variety in real-world emissions between different vehicles, in particular under urban conditions. Some vehicles demonstrate the possibility of achieving low emissions under urban conditions, but the results also clearly show that this is not the case for most of the trucks. This outcome is based on two lines of research. Firstly, the real world emissions of eleven trucks and one bus were measured on-road using a Portable Emission Measurement System (PEMS), under conditions typical of everyday use. Secondly, AdBlue consumption data for a number of Dutch vehicle fleets were analysed. AdBlue is the reagent that is used for NOx emission reduction in SCR systems (catalytic after treatment systems), and the amount of reagent used in daily practice is related to the real-world NOx emissions. Both lines of research support the general outcome.

  15. Modeling the Formation of N2O and NO2 in the Thermal De-NOx Process

    DEFF Research Database (Denmark)

    Miller, James A.; Glarborg, Peter

    1996-01-01

    A chemical kinetic model is formulated that satisfactorily predicts the NO removed and the N2O and NO2 produced by the Thermal De-NOx process over a wide range of temperatures and initial oxygen concentrations....

  16. Multiphase catalysts for selective reduction of NOx with hydrocarbons

    International Nuclear Information System (INIS)

    Maisuls, S.E.

    2000-01-01

    Among the existing proposed solutions to reduce emission of NOx there is a promising alternative, the so-called (HC-SCR) selective catalytic reduction of NOx using hydrocarbons as reductant. This thesis is part of a worldwide effort devoted to gain knowledge on the selective catalytic reduction of NOx with hydrocarbons with the final goal to contribute to the development of suitable catalysts for the above mentioned process. Chapter 2 describes the details of the experimental set-up and of the analytical methods employed. Among the catalyst for HC-SCR, Co-based catalyst are known to be active and selective, thus, a study on a series of Co-based catalysts, supported on zeolites, was undertaken and the results are presented in Chapter 3. Correlation between catalytic characteristics and kinetic results are employed to understand the working catalyst and this is used as a basis for catalyst optimization. With the intention to prepare a multi-functional catalyst that will preserve the desired characteristics of the individual components, minimizing their negative aspects, catalysts based on Co-Pt, supported on ZSM-5, were investigated. In Chapter 4 the results of this study are discussed. A bimetallic Co-Pt/ZSM-5 catalysts with low Pt contents (0.1 wt %) showed a synergistic effect by combining high stability and activity of Pt catalysts with the high N2 selectivity of Co catalysts. Furthermore, it was found to be sulfur- and water-tolerant. Its positive qualities brought us to study the mechanism that takes place over this catalyst during HC-SCR. The results of an in-situ i.r mechanistic study over this catalyst is reported in Chapter 5. From the results presented in Chapter 5 a mechanism operating over the Co-Pt/ZSM-5 catalyst is proposed. The modification of Co catalyst with Pt improved the catalysts. However, further improvement was found to be hindered by high selectivity to N2O. Since Rh catalysts are generally less selective to N2O, the modification of Co

  17. Catalytic devices

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Ming; Zhang, Xiang

    2018-01-23

    This disclosure provides systems, methods, and apparatus related to catalytic devices. In one aspect, a device includes a substrate, an electrically insulating layer disposed on the substrate, a layer of material disposed on the electrically insulating layer, and a catalyst disposed on the layer of material. The substrate comprises an electrically conductive material. The substrate and the layer of material are electrically coupled to one another and configured to have a voltage applied across them.

  18. Determination of adsorptive and catalytic properties of copper, silver and iron contain titanium-pillared bentonite for the removal bisphenol A from aqueous solution

    Science.gov (United States)

    Tomul, Fatma; Turgut Basoglu, Funda; Canbay, Hale

    2016-01-01

    Ti-pillared bentonite, Cu, Ag and Fe modified Ti-pillared bentonite and Cu/Ti- and Fe/Ti-mixed pillared bentonite were synthesized using different titanium sources by direct synthesis or by modification after synthesis. The effects of synthesis conditions on the surface characteristics, pore structure and acidity of the pillared bentonites were investigated by SEM⿿EDS, XPS, XRD, N2-adsorption/desorption and FTIR analyses before and after ammonia adsorption. The results of EDS, XPS and XRD analysis confirmed that titanium, copper, silver and iron were incorporated into the bentonite structure. In the XRD patterns, the formation of delaminated structure reflecting the non-parallel distribution of the bentonite layers by pillaring with Ti, Cu/Ti and Fe/Ti-pillars was observed. XPS spectra indicated the presence of TiO2, CuO, Ag and Ag2O and Fe2O3 species depending on the source of active metals in the synthesized samples. In the FTIR spectra, an increase in the Bronsted/Lewis peak intensity was observed with the loading of copper and iron, whereas a decrease in Lewis and Bronsted acidities was observed with incorporation of silver. Adsorption studies indicated that the adsorption capacity of the sample synthesized using titanium (IV) propoxide and incorporating iron to the structure by ion exchange (Fe-PTi-PILC) were higher than those in other samples. The adsorption of BPA (bisphenol A) by all tested samples was found to fit the Langmuir isotherm. In the catalytic wet peroxide oxidation (CWPO) over PTi-PILC (prepared by titanium (IV) propoxide), Fe-PTi-PILC and Cu-PTi-PILC (prepared by copper impregnated Ti-pillared bentonite) samples, BPA values close to complete conversion were achieved within 30 min at 25 °C, pH 4 and 5 g/L mcat. CWPO results showed that increasement of pH causes a decrease the rate of oxidation. On the other hand, by the time catalyst and BPA concentration is increased, the rate of oxidation is increased as well.

  19. Robust, Model-Based Urea Dosing Control for SCR Aftertreatment Systems using a Cross-Sensitive Tailpipe NOx Sensor

    NARCIS (Netherlands)

    Hommen, G.; Kupper, F.; Seykens, X.

    2017-01-01

    This article describes a NOx sensor based urea dosing control strategy for heavy-duty diesel aftertreatment systems using Selective Catalytic Reduction. The dosing control strategy comprises of a fast-response, model-based ammonia storage control system in combination with a long-timescale

  20. Pilot‐scale investigation and CFD modeling of particle deposition in low‐dust monolithic SCR DeNOx catalysts

    DEFF Research Database (Denmark)

    Heiredal, Michael Lykke; Jensen, Anker Degn; Thøgersen, Joakim Reimer

    2013-01-01

    Deposition of particles in selective catalytic reduction DeNOx monolithic catalysts was studied by low‐dust pilot‐scale experiments. The experiments showed a total deposition efficiency of about 30%, and the deposition pattern was similar to that observed in full‐scale low‐dust applications. On e...

  1. Effect of the synthetic zeolite modification on its physicochemical and catalytic properties in the preparation of the catalysts effectively removing sulphur dioxide from exhaust gases

    Directory of Open Access Journals (Sweden)

    Marcewicz-Kuba Agnieszka

    2016-06-01

    Full Text Available This work presents the research results of the influence of modification deSONOx type catalyst of the sulfur dioxide emissions in the process of the hard coal combustion. The addition of zeolite catalysts modified by transition metal ions: V, Mg, activated by zinc sorbent with or without graphite addition caused the deeper burning of coal grains. The addition of the deSOx catalysts to the coal resulted in lowered sulphur dioxide emission. The addition of unmodified zeolite to coal during combustion reduced sulphur dioxide emission at about 5%. The modification of the support by both V and Mg reduced the amount of sulphur dioxide significantly. The obtained results of SO2 removal from exhaust gases were from 34.5% for Sip/Mg to 68.3% for Sip/V.

  2. Development of adsorption process for NOx recycling in a reprocessing plant

    International Nuclear Information System (INIS)

    Matsuoka, Shingo; Kodama, Takashi; Kumagai, Mikio; Tamura, Takaaki; Izumi, Jun; Someya, Hiroshi

    2003-01-01

    A large amount of NOx, which is used in a reprocessing plant mainly as an oxidizing agent of Pu 3+ , eventually results in the formation of low-level radioactive sodium nitrate waste. Since NOx is generated by the reaction of sodium nitrite and nitric acid, non-radioactive sodium nitrate is also formed as a by-product. In order to reduce the amounts of radioactive and non-radioactive sodium nitrate wastes, a new method was examined to recover NOx for recycling from the off-gas of the denitrator of uranyl nitrate solution. Fundamental and consequent bench scale experiments showed that the vacuum pressure swing adsorption method, using combined silica-gel and clinoptilolite for water vapor removal and pentasil zeolite for NOx recovery, is applicable for this purpose. (author)

  3. An overview of photocatalysis phenomena applied to NOx abatement.

    Science.gov (United States)

    Ângelo, Joana; Andrade, Luísa; Madeira, Luís M; Mendes, Adélio

    2013-11-15

    This review provides a short introduction to photocatalysis technology in terms of the present environmental remediation paradigm and, in particular, NOx photoabatement. The fundamentals of photoelectrochemical devices and the photocatalysis phenomena are reviewed, highlighting the main reaction mechanisms. The critical historical developments on heterogeneous photocatalysis are briefly discussed, giving particular emphasis to the pioneer works in this field. The third part of this work focus mainly on NOx removal technology considering topics such as: TiO2 photochemistry; effect of the operating conditions on the photocatalysis process; Langmuir-Hinshelwood modeling; TiO2 photocatalytic immobilization approaches; and their applications. The last section of the paper presents the main conclusions and perspectives on the opportunities related to this technology. Copyright © 2013 Elsevier Ltd. All rights reserved.

  4. The removal of low level in organics via electro generated hydrogen peroxide in the presence of catalytic amounts of Fe{sup 2+}

    Energy Technology Data Exchange (ETDEWEB)

    Marrosu, G.; Petrucci, R.; Trazza, A. [Rome Univ. La Sapienza (Italy). Dipt. di Ingegneria

    2001-04-01

    Low level phosphites and hypophosphites were completely converted into phosphates via hydrogen peroxide generated by cathodic reduction of oxygen in acidic aqueous medium at a reticulated vitreous carbon electrode, in the presence of little amounts of Fe{sup 2+}. The contemporary regeneration of Fe{sup 2+} by cathodic reduction of Fe{sup 3+}, produced by the well known Fenton reaction, furnishes an excellent way to continuously produce little amount of the Fenton reactive and, as a consequence, of the powerful oxidant hydroxyl radical HO. The best conditions for the complete removal of phosphorus as phosphites and hypophosphites are reported. [Italian] Fosfiti ed ipofosfiti in bassa concentrazione sono stati convertiti completamente in fosfati mediante perossido di idrogeno generato per riduzione catodica dell'ossigeno in mezzo acquoso acido su elettrodo di carbone vetroso reticolato, in presenza di piccole quantita' di Fe{sup 2+}. La contemporanea rigenerazione di Fe{sup 2+} per riduzione catodica di Fe{sup 3+}, prodotto secondo la nota reazione di Fenton, fornisce un' eccellente via per produrre in modo continuo quantita' del reattivo di Fenton, e di conseguenza, del potente ossidante radicale idrossile HO. Vengono riportate le migliori condizioni operative per la completa rimozione del fosforo presente sotto forma di fosfiti e ipofosfiti.

  5. 40 CFR 97.82 - NOX authorized account representative.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false NOX authorized account representative... PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS Individual Unit Opt-ins. § 97.82 NOX authorized account representative. A unit for which an application for a NOX...

  6. 40 CFR 97.50 - NOX Allowance Tracking System accounts.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false NOX Allowance Tracking System accounts... PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS NOX Allowance Tracking System § 97.50 NOX Allowance Tracking System accounts. (a) Nature and function of compliance...

  7. 40 CFR 96.50 - NOX Allowance Tracking System accounts.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false NOX Allowance Tracking System accounts... PROGRAMS (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS FOR STATE IMPLEMENTATION PLANS NOX Allowance Tracking System § 96.50 NOX Allowance Tracking System accounts. (a) Nature and...

  8. Novel Catalytic Membrane Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Stuart Nemser, PhD

    2010-10-01

    There are many industrial catalytic organic reversible reactions with amines or alcohols that have water as one of the products. Many of these reactions are homogeneously catalyzed. In all cases removal of water facilitates the reaction and produces more of the desired chemical product. By shifting the reaction to right we produce more chemical product with little or no additional capital investment. Many of these reactions can also relate to bioprocesses. Given the large number of water-organic compound separations achievable and the ability of the Compact Membrane Systems, Inc. (CMS) perfluoro membranes to withstand these harsh operating conditions, this is an ideal demonstration system for the water-of-reaction removal using a membrane reactor. Enhanced reaction synthesis is consistent with the DOE objective to lower the energy intensity of U.S. industry 25% by 2017 in accord with the Energy Policy Act of 2005 and to improve the United States manufacturing competitiveness. The objective of this program is to develop the platform technology for enhancing homogeneous catalytic chemical syntheses.

  9. On the Effect of Preparation Methods of PdCe-MOR Catalysts as NOx CH4-SCR System for Natural Gas Vehicles Application

    Directory of Open Access Journals (Sweden)

    Acácio Nobre Mendes

    2015-10-01

    Full Text Available In the present work, the effect of several parameters involved in the preparation of PdCe-HMOR catalysts active for NOx selective catalytic reduction with methane (NOx CH4-SCR was studied. Results show that the catalytic performance of Pd-HMOR is better when palladium is introduced by ion-exchange, namely at room temperature. It was also shown that Pd loading does not influence the formation of cerium species, namely surface Ce4+ (CeO2 species and CeO2 species in interaction with Pd. However, when Ce is introduced before Pd, more surface CeO2 species are stabilized in the support and less CeO2 become in interaction with Pd, which results in a worse NOx CH4-SCR catalytic performance.

  10. Catalytic Decoupling of Quantum Information

    DEFF Research Database (Denmark)

    Majenz, Christian; Berta, Mario; Dupuis, Frédéric

    2017-01-01

    The decoupling technique is a fundamental tool in quantum information theory with applications ranging from quantum thermodynamics to quantum many body physics to the study of black hole radiation. In this work we introduce the notion of catalytic decoupling, that is, decoupling in the presence...... of an uncorrelated ancilla system. This removes a restriction on the standard notion of decoupling, which becomes important for structureless resources, and yields a tight characterization in terms of the max-mutual information. Catalytic decoupling naturally unifies various tasks like the erasure of correlations...

  11. Regional Marginal Abatement Cost Curves for NOx

    Data.gov (United States)

    U.S. Environmental Protection Agency — Data underlying the figures included in the manuscript "Marginal abatement cost curve for NOx incorporating controls, renewable electricity, energy efficiency and...

  12. Nox-4 and progressive kidney disease.

    Science.gov (United States)

    Thallas-Bonke, Vicki; Jandeleit-Dahm, Karin A M; Cooper, Mark E

    2015-01-01

    Nox-4 is a member of the NADPH oxidase (Nox) family of enzymes implicated in reactive oxygen species generation. Nox-4 is distributed in many tissues; however, its physiological functions remain poorly understood. In contrast to other Nox isoforms, it is unique in that it produces large amounts of hydrogen peroxide constitutively and does not require other cytosolic oxidase components for its activation. This review highlights the recent developments in Nox-4 research and progressive kidney disease as well as the potential of new Nox-4 inhibitors to reduce renal damage. Recently, Nox-4 was shown to be implicated in kidney diseases such as diabetic nephropathy. Nox-4 has been identified as playing a role in damage to the kidney induced by hyperglycaemia and other major pathways of renal damage, including advanced glycation end-products, the renin-angiotensin system, TGF-β and protein kinase C. The role of Nox-4 as a target for renoprotection remains controversial, although recent positive preclinical data have stimulated increased interest in inhibiting the enzyme in clinical trials of renal disease.

  13. 40 CFR 97.52 - NOX Allowance Tracking System responsibilities of NOX authorized account representative.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false NOX Allowance Tracking System responsibilities of NOX authorized account representative. 97.52 Section 97.52 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR...

  14. The Gothenburg Protocol: NOx emissions problematic for Norway

    International Nuclear Information System (INIS)

    Lind, Oddvar

    2000-01-01

    The Gothenburg Protocol concerns long-range air pollution and is a continuation of earlier protocols and agreements. Its recommendations are based on calculations of where the greatest possible health- and environmental impact is obtained per dollar invested. European countries have done much to reduce the emission of sulphur dioxide. Norway and most other countries, however, have difficulties reducing their emissions of nitrogen oxides. In Norway, the emission of sulphur dioxide must also be substantially reduced, as the tolerance limit for SO2 in nature is low. It is socio-economically profitable for Norway to conform to the Gothenburg Protocol. One of the largest environmental problems in Norway is acid rain and death of fish. Although it is difficult to calculate the exact values of fishing-lakes and of reduced health injuries when the emissions of harmful waste gases are reduced, the profit is very high. 90% of the SO2 pollution in Norway is long-range transported from abroad. Yet Norway must reduce the domestic emissions from 30 000 to 22 000 tonnes the next 10 years. Most of the present emission of SO2 in Norway comes from the production of metals. The reduction goal can be achieved by a combination of improving industrial processes, SO2 cleaning, and reducing the sulphur content of oil. In many European countries, the greatest problem is the increasing emission of NOx and formation of ozone at the ground, which is largely due to the rapidly increasing motor traffic. In Norway, most of the NOx emission comes from the coastal traffic and the fishing fleet, followed by the motor traffic, the petroleum industry and the processing industry. The most cost-effective NOx reductions can be obtained in the North Sea by installing low-NOx gas turbines. In ships, catalytic cleaning of NOx and engine improvements will contribute. On land, the goods traffic can be made more efficient. Most of the emission of ammonia comes from agriculture, where special measures are

  15. Diffuse Reflectance Infrared Fourier Transform Study of NOx Adsorption on CGO10 Impregnated with K2O or BaO

    DEFF Research Database (Denmark)

    Traulsen, Marie Lund; Härelind Ingelsten, H.; Kammer Hansen, Kent

    2012-01-01

    In the present work Diffuse Reflectance Infrared Fourier Transform (DRIFT) spectroscopy is applied to study the adsorption of NOx at 300-500 °C in different atmospheres on gadolinium doped ceria (CGO), an important material in electrodes investigated for electrochemical NOx removal. Furthermore...

  16. SELECTIVE NOx RECIRCULATION FOR STATIONARY LEAN-BURN NATURAL GAS ENGINES

    Energy Technology Data Exchange (ETDEWEB)

    Nigel Clark; Gregory Thompson; Richard Atkinson; Chamila Tissera; Matt Swartz; Emre Tatli; Ramprabhu Vellaisamy

    2005-01-01

    The research program conducted at the West Virginia University Engine and Emissions Research Laboratory (EERL) is working towards the verification and optimization of an approach to remove nitric oxides from the exhaust gas of lean burn natural gas engines. This project was sponsored by the US Department of Energy, National Energy Technology Laboratory (NETL) under contract number: DE-FC26-02NT41608. Selective NOx Recirculation (SNR) involves three main steps. First, NOx is adsorbed from the exhaust stream, followed by periodic desorption from the aftertreatment medium. Finally the desorbed NOx is passed back into the intake air stream and fed into the engine, where a percentage of the NOx is decomposed. This reporting period focuses on the NOx decomposition capability in the combustion process. Although researchers have demonstrated NOx reduction with SNR in other contexts, the proposed program is needed to further understand the process as it applies to lean burn natural gas engines. SNR is in support of the Department of Energy goal of enabling future use of environmentally acceptable reciprocating natural gas engines through NOx reduction under 0.1 g/bhp-hr. The study of decomposition of oxides of nitrogen (NOx) during combustion in the cylinder was conducted on a 1993 Cummins L10G 240 hp lean burn natural gas engine. The engine was operated at different air/fuel ratios, and at a speed of 800 rpm to mimic a larger bore engine. A full scale dilution tunnel and analyzers capable of measuring NOx, CO{sub 2}, CO, HC concentrations were used to characterize the exhaust gas. Commercially available nitric oxide (NO) was used to mimic the NOx stream from the desorption process through a mass flow controller and an injection nozzle. The same quantity of NOx was injected into the intake and exhaust line of the engine for 20 seconds at various steady state engine operating points. NOx decomposition rates were obtained by averaging the peak values at each set point minus

  17. AMMONOX-Ammonia for enhancing biogas yield & reducing NOx

    DEFF Research Database (Denmark)

    Gavala, Hariklia N.; Kristensen, P.G.; Paamand, K.

    2013-01-01

    The continuously increasing demand for renewable energy sources renders anaerobic digestion to one of the most promising technologies for renewable energy production. Due to the animal production intensification, manure is being used as the primary feedstock for most of the biogas plants. However......, biogas plants digesting liquid manure alone are not economically viable due to the relatively low organic content of the manure, usually 3-5%.Thus, their economical profitable operation relies partly on increasing the methane yield from manure, and especially of its solid fraction, usually called...... of innovative ammonia recovery technology and c) the coupling of the excess ammonia obtained from manure with the catalytic elimination of NOx emissions when the biogas is used for subsequent electricity generation with gas engines....

  18. Physico-Chemical and Structural Properties of DeNOx and SO2 Oxidation Catalysts

    DEFF Research Database (Denmark)

    Masters, Stephen Grenville; Oehlers, Cord; Nielsen, Kurt

    1996-01-01

    Commercial catalysts for NOx removal and SO2 oxidation and their model systems have been investigated by spectroscopic, thermal, electrochemical and X-ray methods. Structural information on the vanadium complexes and compounds as well as physico-chemical properties for catalyst model systems have...

  19. Selective NOx Recirculation for Stationary Lean-Burn Natural Gas Engines

    Energy Technology Data Exchange (ETDEWEB)

    Nigel Clark; Gregory Thompson; Richard Atkinson; Richard Turton; Chamila Tissera; Emre Tatli; Andy Zimmerman

    2005-12-28

    address modeling and preliminary design of the heat exchanger, demister and NOx sorbent chamber suitable for a given engine. A simplified linear driving force model was developed to predict NOx adsorption into the sorbent material as cooled exhaust passes over fresh sorbent material. This aspect of the research will continue into 2006, and the benefits and challenges of SNR will be compared with those of competing systems, such as Selective Catalytic Reduction. Chemical kinetic modeling using the CHEMKIN software package was extended in 2005 to the case of slightly rich burn with EGR. Simulations were performed at 10%, 20%, 30% and 40% of the intake air replaced with EGR. NOx decomposition efficiency was calculated at the point in time where 98% of fuel was consumed, which is believed to be a conservative approach. The modeling data show that reductions of over 70% are possible using the ''98% fuel burned'' assumption.

  20. COST-EFFECTIVE CONTROL OF NOx WITH INTEGRATED ULTRA LOW-NOx BURNERS AND SNCR

    Energy Technology Data Exchange (ETDEWEB)

    Hamid Farzan; Jennifer Sivy; Alan Sayre; John Boyle

    2003-07-01

    Under sponsorship of the Department of Energy's National Energy Technology Laboratory (NETL), McDermott Technology, Inc. (MTI), the Babcock & Wilcox Company (B&W), and Fuel Tech teamed together to investigate an integrated solution for NOx control. The system was comprised of B&W's DRB-4Z{trademark} low-NO{sub x} pulverized coal (PC) burner technology and Fuel Tech's NO{sub x}OUT{reg_sign}, a urea-based selective non-catalytic reduction (SNCR) technology. The technology's emission target is achieving 0.15 lb NO{sub x}/10{sup 6} Btu for full-scale boilers. Development of the low-NOx burner technology has been a focus in B&W's combustion program. The DRB-4Z{trademark} burner (see Figure 1.1) is B&W's newest low-NO{sub x} burner capable of achieving very low NO{sub x}. The burner is designed to reduce NO{sub x} by diverting air away from the core of the flame, which reduces local stoichiometry during coal devolatilization and, thereby, reduces initial NO{sub x} formation. Figure 1.2 shows the historical NO{sub x} emission levels from different B&W burners. Figure 1.2 shows that based on three large-scale commercial installations of the DRB-4Z{trademark} burners in combination with OFA ports, using Western subbituminous coal, the NO{sub x} emissions ranged from 0.16 to 0.18 lb/10{sup 6} Btu. It appears that with continuing research and development the Ozone Transport Rule (OTR) emission level of 0.15 lb NO{sub x}/10{sup 6} Btu is within the reach of combustion modification techniques for boilers using western U.S. subbituminous coals. Although NO{sub x} emissions from the DRB-4Z{trademark} burner are nearing OTR emission level with subbituminous coals, the utility boiler owners that use bituminous coals can still benefit from the addition of an SNCR and/or SCR system in order to comply with the stringent NO{sub x} emission levels facing them.

  1. Trends in catalytic NO decomposition over transition metal surfaces

    DEFF Research Database (Denmark)

    Falsig, Hanne; Bligaard, Thomas; Rass-Hansen, Jeppe

    2007-01-01

    The formation of NOx from combustion of fossil and renewable fuels continues to be a dominant environmental issue. We take one step towards rationalizing trends in catalytic activity of transition metal catalysts for NO decomposition by combining microkinetic modelling with density functional...... theory calculations. We show specifically why the key problem in using transition metal surfaces to catalyze direct NO decomposition is their significant relative overbinding of atomic oxygen compared to atomic nitrogen....

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

    Science.gov (United States)

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

    2009-05-15

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

  3. Rho Kinase ROCK2 Mediates Acid-Induced NADPH Oxidase NOX5-S Expression in Human Esophageal Adenocarcinoma Cells.

    Directory of Open Access Journals (Sweden)

    Jie Hong

    Full Text Available Mechanisms of the progression from Barrett's esophagus (BE to esophageal adenocarcinoma (EA are not fully understood. We have shown that NOX5-S may be involved in this progression. However, how acid upregulates NOX5-S is not well known. We found that acid-induced increase in NOX5-S expression was significantly decreased by the Rho kinase (ROCK inhibitor Y27632 in BE mucosal biopsies and FLO-1 EA cells. In addition, acid treatment significantly increased the Rho kinase activity in FLO-1 cells. The acid-induced increase in NOX5-S expression and H2O2 production was significantly decreased by knockdown of Rho kinase ROCK2, but not by knockdown of ROCK1. Conversely, the overexpression of the constitutively active ROCK2, but not the constitutively active ROCK1, significantly enhanced the NOX5-S expression and H2O2 production. Moreover, the acid-induced increase in Rho kinase activity and in NOX5-S mRNA expression was blocked by the removal of calcium in both FLO-1 and OE33 cells. The calcium ionophore A23187 significantly increased the Rho kinase activity and NOX5-S mRNA expression. We conclude that acid-induced increase in NOX5-S expression and H2O2 production may depend on the activation of ROCK2, but not ROCK1, in EA cells. The acid-induced activation of Rho kinase may be mediated by the intracellular calcium increase. It is possible that persistent acid reflux present in BE patients may increase the intracellular calcium, activate ROCK2 and thereby upregulate NOX5-S. High levels of reactive oxygen species derived from NOX5-S may cause DNA damage and thereby contribute to the progression from BE to EA.

  4. Recent Developments of Electrochemical Promotion of Catalysis in the Techniques of DeNOx

    Science.gov (United States)

    Tang, Xiaolong; Yi, Honghong; Chen, Chen; Wang, Chuan

    2013-01-01

    Electrochemical promotion of catalysis reactions (EPOC) is one of the most significant discoveries in the field of catalytic and environmental protection. The work presented in this paper focuses on the aspects of reaction mechanism, influencing factors, and recent positive results. It has been shown with more than 80 different catalytic systems that the catalytic activity and selectivity of conductive catalysts deposited on solid electrolytes can be altered in the last 30 years. The active ingredient of catalyst can be activated by applying constant voltage or constant current to the catalysts/electrolyte interface. The effect of EPOC can improve greatly the conversion rate of NOx. And it can also improve the lifetime of catalyst by inhibiting its poisoning. PMID:23970835

  5. 40 CFR 96.82 - NOX authorized account representative.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false NOX authorized account representative... PROGRAMS (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS FOR STATE IMPLEMENTATION PLANS Individual Unit Opt-ins § 96.82 NOX authorized account representative. A unit for which an...

  6. Reduction of NOx and PM in Marine Diesel Engine Exhaust Gas using Microwave Plasma

    OpenAIRE

    Balachandran, W; Beleca, R; Abbod, M; Manivannan, N

    2015-01-01

    Abatement of NOx and particulate matters (PM) of marine diesel exhaust gas using microwave (MW) non-thermal plasma is presented in this paper. NOx mainly consist of NO and less concentration of NO2 in a typical two stoke marine diesel engine and microwave plasma generation can completely remove NO. MW was generated using two 2kW microwave sources and a saw tooth passive electrode. Passive electrode was used to generate high electric field region within microwave environment where high energet...

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

    Science.gov (United States)

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

    2015-12-15

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

  8. Development of Green Pavement for Reducing Oxides of Nitrogen (NOx in the Ambient Air

    Directory of Open Access Journals (Sweden)

    Kania Dewi

    2016-05-01

    Full Text Available The transportation sector is the biggest contributor to air pollution in Indonesia, especially in metropolitan cities. Gases such as oxides of nitrogen (NOx are produced during the combustion of fossil fuels in the internal combustion of vehicle engines. Oxides of nitrogen such as nitric oxide (NO and nitrogen dioxide (NO2 are important air pollutants, because they cause significant harm to human health and play an important role in being precursors of other dangerous pollutants such as photochemical smog. One of the simple ways to reduce NOx concentrations is utilizing a catalytic process involving UV light and semiconductor particles such as TiO2. Illuminated TiO2 UV light is capable of producing an electron (e- and hole (h- pair, which initiates a chemical reaction that alters the NOx to become NO3- or NO2-. A field scale paving block reactor coated with TiO2 placed by the roadside was exposed to UV light using various exposure times. The results showed that the sample with a composition of 200 g/m2 TiO2 was capable of adsorbing NOx gas at an average rate of 0.0046 mg/m2/minute. Additional costs due to TiO2 coating for every square meter of paving are IDR 13,180.

  9. 40 CFR 96.388 - CAIR NOX Ozone Season allowance allocations to CAIR NOX Ozone Season opt-in units.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false CAIR NOX Ozone Season allowance allocations to CAIR NOX Ozone Season opt-in units. 96.388 Section 96.388 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND...

  10. 40 CFR 75.71 - Specific provisions for monitoring NOX and heat input for the purpose of calculating NOX mass...

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 16 2010-07-01 2010-07-01 false Specific provisions for monitoring NOX and heat input for the purpose of calculating NOX mass emissions. 75.71 Section 75.71 Protection of... MONITORING NOX Mass Emissions Provisions § 75.71 Specific provisions for monitoring NOX and heat input for...

  11. 40 CFR 96.12 - Changing the NOX authorized account representative and the alternate NOX authorized account...

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Changing the NOX authorized account representative and the alternate NOX authorized account representative; changes in the owners and operators. 96... (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS FOR STATE IMPLEMENTATION PLANS...

  12. Correlating Engine NOx Emission with Biodiesel Composition

    Science.gov (United States)

    Jeyaseelan, Thangaraja; Mehta, Pramod Shankar

    2017-06-01

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

  13. New fuel air control strategy for reducing NOx emissions from corner-fired utility boilers at medium-low loads

    DEFF Research Database (Denmark)

    Zhao, Sinan; Fang, Qingyan; Yin, Chungen

    2017-01-01

    Due to the rapidly growing renewable power, the fossil fuel power plants have to be increasingly operated under large and rapid load change conditions, which can induce various challenges. This work aims to reduce NOx emissions of large-scale corner-fired boilers operated at medium–low loads....... The combustion characteristics and NOx emissions from a 1000 MWe corner-fired tower boiler under different loads are investigated experimentally and numerically. A new control strategy for the annular fuel air is proposed and implemented in the boiler, in which the secondary air admitted to the furnace through...... of the selective catalytic reduction (SCR) system by about 20% at medium–low loads, compared to those based on the original control. The new control strategy has also been successfully applied to two other corner-fired boilers to achieve a significant NOx emission reduction at partial loads. In all three...

  14. Study of the "Fast SCR" -like mechanism of H2-assisted SCR of NOx with ammonia over Ag/Al2O3

    DEFF Research Database (Denmark)

    Doronkin, Dmitry E.; Fogel, Sebastian; Tamm, Stefanie

    2012-01-01

    It is shown that Ag/Al2O3 is a unique catalytic system for H2-assisted selective catalytic reduction of NOx by NH3 (NH3-SCR) with both Ag and alumina being necessary components of the catalyst. The ability of Ag/Al2O3 and pure Al2O3 to catalyse SCR of mixtures of NO and NO2 by ammonia is demonstr......It is shown that Ag/Al2O3 is a unique catalytic system for H2-assisted selective catalytic reduction of NOx by NH3 (NH3-SCR) with both Ag and alumina being necessary components of the catalyst. The ability of Ag/Al2O3 and pure Al2O3 to catalyse SCR of mixtures of NO and NO2 by ammonia...... is demonstrated, the surface species occurring discussed, and a "Fast SCR" -like mechanism of the process is proposed. The possibility of catalyst surface blocking by adsorbed NOx and the influence of hydrogen on desorption of NOx were evaluated by FTIR and DFT calculations. © 2011 Elsevier B.V....

  15. Sulfur poisoning and regeneration of the Ag/γ-Al2O3 catalyst for H2-assisted SCR of NOx by ammonia

    DEFF Research Database (Denmark)

    Doronkin, Dmitry E.; Khan, Tuhin Suvra; Bligaard, Thomas

    2012-01-01

    Sulfur poisoning and regeneration mechanisms for a 2% Ag/γ-Al2O3 catalyst for the H2-assisted selective catalytic reduction of NOx by NH3 are investigated. The catalyst has medium sulfur tolerance at low temperatures, however a good capability of regeneration at 670°C under lean conditions when H2...

  16. Dry and semi-dry methods for removal of ammonia from pulverized fuel combustion fly ash

    Energy Technology Data Exchange (ETDEWEB)

    Y. Gao; X. Chen; G. Fujisaki; A. Mehta; E. Suuberg; R. Hurt [Brown University, Providence, RI (United States). Division of Engineering

    2002-12-01

    Fly ash from pulverized solid fuel combustion can become contaminated by ammonia during selective catalytic/noncatalytic NOx reduction processes and/or electrostatic precipitator conditioning, resulting in problems with the commercial handling, disposal, and utilization of ash. The present paper investigates the chemistry of a class of postcombustion ammonia removal processes that operate near room temperature and in the dry or semi-dry state. Laboratory experiments are carried out in which ammonia is liberated from fly ash through introduction of controlled amounts of water to the interparticle spaces using static humid air, flowing humid air, and/or flowing fog (water aerosol). Additional experiments explore the possibility of destroying ammonia using ozone as a low-temperature oxidant under both dry and wet conditions, alone or in combination with hydrogen peroxide. 28 refs., 11 figs., 3 tabs.

  17. OXYGEN ENHANCED COMBUSTION FOR NOx CONTROL

    Energy Technology Data Exchange (ETDEWEB)

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

    2004-04-01

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

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

    Directory of Open Access Journals (Sweden)

    Cheolyong Choi

    2015-11-01

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

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

    Science.gov (United States)

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

    2015-11-01

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

  20. Ag Active Sites, Surface Intermediates and Hydrogen Function at decane-SCR-Nox over Ag/Alumina

    Czech Academy of Sciences Publication Activity Database

    Sazama, Petr; Wichterlová, Blanka; Sobalík, Zdeněk; Nováková, Jana; Dědeček, Jiří

    2007-01-01

    Roč. 172, - (2007), s. 501-504 ISSN 0167-2991. [Tokyo Conference in Advanced Catalytic Science and Technology /5./. Tokyo, 23.07.2007-28.07.2007] R&D Projects: GA AV ČR 1ET400400413; GA ČR GD203/03/H140 Institutional research plan: CEZ:AV0Z40400503 Keywords : SCR- NOx * Ag active sites * surface intermediates Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 0.307, year: 2005

  1. Organizers and activators: Cytosolic Nox proteins impacting on vascular function.

    Science.gov (United States)

    Schröder, Katrin; Weissmann, Norbert; Brandes, Ralf P

    2017-08-01

    NADPH oxidases of the Nox family are important enzymatic sources of reactive oxygen species (ROS) in the cardiovascular system. Of the 7 members of the Nox family, at least three depend for their activation on specific cytosolic proteins. These are p47phox and its homologue NoxO1 and p67phox and its homologue NoxA1. Also the Rho-GTPase Rac is important but as this protein has many additional functions, it will not be covered here. The Nox1 enzyme is preferentially activated by the combination of NoxO1 with NoxA1, whereas Nox2 gains highest activity with p47phox together with p67phox. As p47phox, different to NoxO1 contains an auto inhibitory region it has to be phosphorylated prior to complex formation. In the cardio-vascular system, all cytosolic Nox proteins are expressed but the evidence for their contribution to ROS production is not well established. Most data have been collected for p47phox, whereas NoxA1 has basically not yet been studied. In this article the specific aspects of cytosolic Nox proteins in the cardiovascular system with respect to Nox activation, their expression and their importance will be reviewed. Finally, it will be discussed whether cytosolic Nox proteins are suitable pharmacological targets to tamper with vascular ROS production. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  2. DEVELOPMENT AND DEMONSTRATION OF NOVEL LOW-NOx BURNERS IN THE STEEL INDUSTRY

    Energy Technology Data Exchange (ETDEWEB)

    Cygan, David

    2006-12-28

    Gas Technology Institute (GTI), together with Hamworthy Peabody Combustion Incorporated (formerly Peabody Engineering Corporation), the University of Utah, and Far West Electrochemical have developed and demonstrated an innovative combustion system suitable for natural gas and coke-oven gas firing within the steel industry. The combustion system is a simple, low-cost, energy-efficient burner that can reduce NOx by more than 75%. The U.S. steel industry needs to address NOx control at its steelmaking facilities. A significant part of NOx emissions comes from gas-fired boilers. In steel plants, byproduct gases – blast furnace gas (BFG) and coke-oven gas (COG) – are widely used together with natural gas to fire furnaces and boilers. In steel plants, natural gas can be fired together with BFG and COG, but, typically, the addition of natural gas raises NOx emissions, which can already be high because of residual fuel-bound nitrogen in COG. The Project Team has applied its expertise in low-NOx burners to lower NOx levels for these applications by combining advanced burner geometry and combustion staging with control strategies tailored to mixtures of natural gas and byproduct fuel gases. These methods reduce all varieties of NOx – thermal NOx produced by high flame temperatures, prompt NOx produced by complex chain reactions involving radical hydrocarbon species and NOx from fuel-bound nitrogen compounds such as ammonia found in COG. The Project Team has expanded GTI’s highly successful low-NOx forced internal recirculation (FIR) burner, previously developed for natural gas-fired boilers, into facilities that utilize BFG and COG. For natural gas firing, these burners have been shown to reduce NOx emissions from typical uncontrolled levels of 80-100 vppm to single-digit levels (9 vppm). This is done without the energy efficiency penalties incurred by alternative NOx control methods, such as external flue gas recirculation (FGR), water injection, and selective non-catalytic

  3. Platinum recovery from used auto catalytic converters in electrorefining process

    Directory of Open Access Journals (Sweden)

    A. Fornalczyk

    2013-04-01

    Full Text Available This paper presents possibility of removing platinum from the used catalytic converters applying copper as a metal collector in pyrometallurgical methods. The catalytic converter carrier was grinded and melted with copper. During the research obtained Cu-Pt alloy was casted as an anode. Such anode was electrically refined in order to recover platinum. Obtained results were discussed.

  4. Simultaneous purifying of Hg0, SO2, and NOx from flue gas by Fe3+/H2O2: the performance and purifying mechanism.

    Science.gov (United States)

    Xing, Yi; Li, Liuliu; Lu, Pei; Cui, Jiansheng; Li, Qianli; Yan, Bojun; Jiang, Bo; Wang, Mengsi

    2018-03-01

    Hg 0 , SO 2 , and NOx result in heavily global environmental pollution and serious health hazards. Up to now, how to efficiently remove mercury with SO 2 and NOx from flue gas is still a tough task. In this study, series of high oxidizing Fenton systems were employed to purify the pollutants. The experimental results showed that Fe 3+ /H 2 O 2 was more suitable to purify Hg 0 than Fe 2+ /H 2 O 2 and Cu 2+ /H 2 O 2. The optimal condition includes Fe 3+ concentration of 0.008 mol/L, Hg 0 inlet concentration of 40 μg/m 3 , solution temperature of 50 °C, pH of 3, H 2 O 2 concentration of 0.7 mol/L, and O 2 percentage of 6%. When SO 2 and NOx were taken into account under the optimal condition, Hg 0 removal efficiency could be enhanced to 91.11% while the removal efficiency of both NOx and SO 2 was slightly declined, which was consistent to the analysis of purifying mechanism. The removal efficiency of Hg 0 was stimulated by accelerating the conversion of Fe 2+ to Fe 3+ , which resulted from the existence of SO 2 and NOx. The results of this study suggested that simultaneously purifying Hg 0 , SO 2 , and NOx from flue gas is feasible.

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

    Science.gov (United States)

    2010-07-01

    ... nitrogen oxides (NOX)? 60.4320 Section 60.4320 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... nitrogen oxides (NOX)? (a) You must meet the emission limits for NOX specified in Table 1 to this subpart... the emission limits for NOX. ...

  6. NOx processing on Solar gas turbines; Turbines, traitement des nox sur les turbines a gaz solar

    Energy Technology Data Exchange (ETDEWEB)

    Chausse, X. [Spie Trindel, 95 - Cergy (France). Service TAG

    1997-12-31

    The Solar Company, in cooperation with Tuma Turbomach, has developed the SoLoNOx combustion system with a dry, lean, premixed compound, allowing for reduced NOx and CO emission levels (respectively 42 ppmv and 50 ppmv at 15 pc O{sub 2}). The combustor size is larger than a conventional combustor in order to maintain combustion efficiency and reduce carbon monoxide levels. Leaner combustion occurs at lower temperatures which produce less nitrogen oxides but require more volume to complete the combustion process. New developments should allow for a further reduction of NOx level at 25 ppmv

  7. Role of Nox4 and Nox2 in Hyperoxia-Induced Reactive Oxygen Species Generation and Migration of Human Lung Endothelial Cells

    OpenAIRE

    Pendyala, Srikanth; Gorshkova, Irina A; Usatyuk, Peter V.; He, Donghong; Pennathur, Arjun; Lambeth, J. David; Thannickal, Victor J.; Natarajan, Viswanathan

    2009-01-01

    In vascular endothelium, the major research focus has been on reactive oxygen species (ROS) derived from Nox2. The role of Nox4 in endothelial signal transduction, ROS production, and cytoskeletal reorganization is not well defined. In this study, we show that human pulmonary artery endothelial cells (HPAECs) and human lung microvascular endothelial cells (HLMVECs) express higher levels of Nox4 and p22phox compared to Nox1, Nox2, Nox3, or Nox5. Immunofluorescence microscopy and Western blot a...

  8. NOx from cement production - reduction by primary measures

    DEFF Research Database (Denmark)

    Jensen, Lars Skaarup

    1999-01-01

    , calciner operation, fuel properties and on the NOx level from the rotary kiln. The low-NOx calciner types presently marketed are based on combinations of reburning, air staging and temperature control and seem equivalent in their ability to restrict NOx formation. If fuels with a significant volatile...... is the most energy demanding process, takes place at lower temperature in the calciner. When dealing with NOx from solid fuel combustion it is important to consider reactions of volatile contents and char separately.Chapter 4 presents an overview of NOx from cement production. Thermal NOx dominates from...... content (> 25%) are used, net reduction of kiln NOx typically takes place in calciners, whereas net NOx formation takes place when low-volatile fuels (...

  9. Simulation on Toxic Gases in Vehicle Exhaust Equipped with Modified Catalytic Converter : A Review

    Directory of Open Access Journals (Sweden)

    Leman A.M.

    2016-01-01

    Full Text Available Air pollution and global warming is a major issue nowadays. One of the main contributors to be the emission of harmful gases produced by vehicle exhausts lines. The harmful gases like NOx, CO, unburned HC and particulate matter increases the global warming, so catalytic converter plays a vital role in reducing harmful gases. Catalytic converters are used on most vehicles on the road today. This research deals with the gas emission flow in the catalytic converter involving the heat transfer, velocity flow, back pressure and others chemical reaction in the modified catalytic converter by using FeCrAl as a substrate that is treated using the ultrasonic bath and electroplating techniques. The objective of this study is to obtain a quantitative description of the gas emission in the catalytic converter system of automobile exhaust gas using ANSYS Software. The description of the gas emission in the catalytic converter system of automobile exhaust gas using ANSYS Software was simulated in this research in order to provide better efficiency and ease the reusability of the catalytic converter by comparing experimental data with software analysing data. The result will be expected to demonstrate a good approximation of gas emission in the modified catalytic converter simulation data compared to experimental data in order to verify the effectiveness of modified catalytic converter. Therefore studies on simulation of flow through the modified catalytic converter are very important to increase the accuracy of the obtained emission result.

  10. 40 CFR 97.11 - Alternate NOX authorized account representative.

    Science.gov (United States)

    2010-07-01

    ... representative. 97.11 Section 97.11 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Authorized Account Representative for NOX Budget Sources § 97.11 Alternate NOX authorized account... representation under § 97.13, any representation, action, inaction, or submission by the alternate NOX authorized...

  11. Catalytic Oligopeptide Synthesis.

    Science.gov (United States)

    Liu, Zijian; Noda, Hidetoshi; Shibasaki, Masakatsu; Kumagai, Naoya

    2018-02-02

    Waste-free catalytic assembly of α-amino acids is fueled by a multiboron catalyst that features a characteristic B 3 NO 2 heterocycle, providing a versatile catalytic protocol wherein functionalized natural α-amino acid units are accommodated and commonly used protecting groups are tolerated. The facile dehydrative conditions eliminate the use of engineered peptide coupling reagents, exemplifying a greener catalytic alternative for peptide coupling. The catalysis is sufficiently robust to enable pentapeptide synthesis, constructing all four amide bond linkages in a catalytic fashion.

  12. Selective catalytic oxidation of ammonia

    Energy Technology Data Exchange (ETDEWEB)

    Leppaelahti, J.; Koljonen, T. [VTT Energy, Espoo (Finland)

    1996-12-31

    In the combustion of fossil fuels, the principal source of nitrogen oxides is nitrogen bound in the fuel structure. In gasification, a large part of fuel nitrogen forms NH{sub 3}, which may form nitrogen oxides during gas combustion. If NH{sub 3} and other nitrogen species could be removed from hot gas, the NO emission could be considerably reduced. However, relatively little attention has been paid to finding new means of removing nitrogen compounds from the hot gasification gas. The possibility of selectively oxidizing NH{sub 3} to N{sub 2} in the hot gasification has been studied at VTT Energy. The largest NH{sub 3} reductions have been achieved by catalytic oxidation on aluminium oxides. (author) (4 refs.)

  13. Solid State Electrochemical DeNOx

    DEFF Research Database (Denmark)

    Kammer Hansen, Kent

    2010-01-01

    The literature on direct electrochemical reduction of NOx in a solid state cell has been reviewed. It is shown that that the reduction of nitric oxide either occurs on the electrode or on the electrolyte if F-centers are formed. It is also shown that some oxide based electrodes has a high apparent...

  14. Alternative alkali resistant deNOx catalysts

    DEFF Research Database (Denmark)

    Putluru, Siva Sankar Reddy; Kristensen, Steffen Buus; Due-Hansen, Johannes

    2012-01-01

    Alternative alkali resistant deNOx catalysts were prepared using three different supports ZrO2, TiO2 and Mordenite zeolite. The majority of the catalysts were prepared by incipient wetness impregnation of a commercial support, with vanadium, copper or iron precursor, one catalyst was prepared...

  15. Structural Insights into Nox4 and Nox2: Motifs Involved in Function and Cellular Localization ▿ †

    OpenAIRE

    von Löhneysen, Katharina; Noack, Deborah; Wood, Malcolm R.; Friedman, Jeffrey S.; Knaus, Ulla G.

    2009-01-01

    Regulated generation of reactive oxygen species (ROS) is primarily accomplished by NADPH oxidases (Nox). Nox1 to Nox4 form a membrane-associated heterodimer with p22phox, creating the docking site for assembly of the activated oxidase. Signaling specificity is achieved by interaction with a complex network of cytosolic components. Nox4, an oxidase linked to cardiovascular disease, carcinogenesis, and pulmonary fibrosis, deviates from this model by displaying constitutive H2O2 production witho...

  16. NOX, NOX who is there?, The contribution of NADPH Oxidase to beta cell dysfunction.

    Directory of Open Access Journals (Sweden)

    David eTaylor-Fishwick

    2013-04-01

    Full Text Available Predictions of diabetes prevalence over the next decades warrant the aggressive discovery of new approaches to stop or reverse loss of functional beta cell mass. Beta cells are recognized to have a relatively high sensitivity to reactive oxygen species (ROS and become dysfunctional under oxidative stress conditions. New discoveries have identified NADPH oxidases in beta cells as contributors to elevated cellular ROS. Reviewed are recent reports that evidence a role for NADPH oxidase-1 (NOX-1 in beta cell dysfunction. NOX-1 is stimulated by inflammatory cytokines that are elevated in diabetes. First, regulation of cytokine-stimulated NOX-1 expression has been linked to inflammatory lipid mediators derived from 12-lipoxyganase activity. For the first time in beta cells these data integrate distinct pathways associated with beta cell dysfunction. Second, regulation of NOX-1 in beta cells involves feed-forward control linked to elevated ROS and Src-kinase activation. This potentially results in unbridled ROS generation and identifies candidate targets for pharmacologic intervention. Third, consideration is provided of new, first-in-class, selective inhibitors of NOX-1. These compounds could have an important role in assessing a disruption of NOX-1/ROS signaling as a new approach to preserve and protect beta cell mass in diabetes.

  17. NOX, NOX Who is There? The Contribution of NADPH Oxidase One to Beta Cell Dysfunction

    Science.gov (United States)

    Taylor-Fishwick, David A.

    2013-01-01

    Predictions of diabetes prevalence over the next decades warrant the aggressive discovery of new approaches to stop or reverse loss of functional beta cell mass. Beta cells are recognized to have a relatively high sensitivity to reactive oxygen species (ROS) and become dysfunctional under oxidative stress conditions. New discoveries have identified NADPH oxidases in beta cells as contributors to elevated cellular ROS. Reviewed are recent reports that evidence a role for NADPH oxidase-1 (NOX-1) in beta cell dysfunction. NOX-1 is stimulated by inflammatory cytokines that are elevated in diabetes. First, regulation of cytokine-stimulated NOX-1 expression has been linked to inflammatory lipid mediators derived from 12-lipoxygenase activity. For the first time in beta cells these data integrate distinct pathways associated with beta cell dysfunction. Second, regulation of NOX-1 in beta cells involves feed-forward control linked to elevated ROS and Src-kinase activation. This potentially results in unbridled ROS generation and identifies candidate targets for pharmacologic intervention. Third, consideration is provided of new, first-in-class, selective inhibitors of NOX-1. These compounds could have an important role in assessing a disruption of NOX-1/ROS signaling as a new approach to preserve and protect beta cell mass in diabetes. PMID:23565109

  18. 40 CFR 97.388 - CAIR NOX Ozone Season allowance allocations to CAIR NOX Ozone Season opt-in units.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false CAIR NOX Ozone Season allowance allocations to CAIR NOX Ozone Season opt-in units. 97.388 Section 97.388 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2002-12-30

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

  20. Agriculture is a major source of NOx pollution in California

    Science.gov (United States)

    Almaraz, Maya; Bai, Edith; Wang, Chao; Trousdell, Justin; Conley, Stephen; Faloona, Ian; Houlton, Benjamin Z.

    2018-01-01

    Nitrogen oxides (NOx = NO + NO2) are a primary component of air pollution—a leading cause of premature death in humans and biodiversity declines worldwide. Although regulatory policies in California have successfully limited transportation sources of NOx pollution, several of the United States’ worst–air quality districts remain in rural regions of the state. Site-based findings suggest that NOx emissions from California’s agricultural soils could contribute to air quality issues; however, a statewide estimate is hitherto lacking. We show that agricultural soils are a dominant source of NOx pollution in California, with especially high soil NOx emissions from the state’s Central Valley region. We base our conclusion on two independent approaches: (i) a bottom-up spatial model of soil NOx emissions and (ii) top-down airborne observations of atmospheric NOx concentrations over the San Joaquin Valley. These approaches point to a large, overlooked NOx source from cropland soil, which is estimated to increase the NOx budget by 20 to 51%. These estimates are consistent with previous studies of point-scale measurements of NOx emissions from the soil. Our results highlight opportunities to limit NOx emissions from agriculture by investing in management practices that will bring co-benefits to the economy, ecosystems, and human health in rural areas of California. PMID:29399630

  1. Research of an Automatic Control Method of NO Removal System by Silent Discharge

    Science.gov (United States)

    Kimura, Kouhei; Hayashi, Kenji; Yoshioka, Yoshio

    An automatic NOx control device was developed for NOx removal system by silent discharge targeting diesel engine generator. A new algorithm of controlling the exit NO concentration at specified values was developed. The control system was actually made in our laboratory and it was confirmed that exit NO concentration could be controlled in the specified value.

  2. A comparative evaluation on the emission characteristics of ceramic and metallic catalytic converter in internal combustion engine

    Science.gov (United States)

    Leman, A. M.; Jajuli, Afiqah; Rahman, Fakhrurrazi; Feriyanto, Dafit; Zakaria, Supaat

    2017-09-01

    Enforcement of a stricter regulation on exhaust emission by many countries has led to utilization of catalytic converter to reduce the harmful pollutant emission. Ceramic and metallic catalytic converters are the most common type of catalytic converter used. The purpose of this study is to evaluate the performance of the ceramic and metallic catalytic converter on its conversion efficiency using experimental measurement. Both catalysts were placed on a modified exhaust system equipped with a Mitshubishi 4G93 single cylinder petrol engine that was tested on an eddy current dynamometer under steady state conditions for several engine speeds. The experimental results show that the metallic catalytic converter reduced a higher percentage of CO up to 98.6% reduction emissions while ceramic catalytic converter had a better reduction efficiency of HC up to 85.4% and 87.2% reduction of NOx.

  3. System Study of Rich Catalytic/Lean burn (RCL) Catalytic Combustion for Natural Gas and Coal-Derived Syngas Combustion Turbines

    Energy Technology Data Exchange (ETDEWEB)

    Shahrokh Etemad; Lance Smith; Kevin Burns

    2004-12-01

    Rich Catalytic/Lean burn (RCL{reg_sign}) technology has been successfully developed to provide improvement in Dry Low Emission gas turbine technology for coal derived syngas and natural gas delivering near zero NOx emissions, improved efficiency, extending component lifetime and the ability to have fuel flexibility. The present report shows substantial net cost saving using RCL{reg_sign} technology as compared to other technologies both for new and retrofit applications, thus eliminating the need for Selective Catalytic Reduction (SCR) in combined or simple cycle for Integrated Gasification Combined Cycle (IGCC) and natural gas fired combustion turbines.

  4. Building Selectivity for NO Sensing in a NOx Mixture with Sonochemically Prepared CuO Structures

    Directory of Open Access Journals (Sweden)

    Max R. Mullen

    2015-12-01

    Full Text Available Several technologies are available for decreasing nitrogen oxide (NOx emissions from combustion sources, including selective catalytic reduction methods. In this process, ammonia reacts with nitric oxide (NO and nitrogen dioxide (NO2. As the stoichiometry of the two reactions is different, electrochemical sensor systems that can distinguish between NO and NO2 in a mixture of these two gases are of interest. Since NO and NO2 can be brought to equilibrium, depending on the temperature and the surfaces that they are in contact with, the detection of NO and NO2 independently is a difficult problem and has not been solved to date. In this study, we explore a high surface area sonochemically prepared CuO as the resistive sensing medium. CuO is a poor catalyst for NOx equilibration, and requires temperatures of 500 C to bring about equilibration. Thus, at 300 C, NO and NO2 retain their levels after interaction with CuO surface. In addition, NO adsorbs more strongly on the CuO over NO2. Using these two concepts, we can detect NO with minimal interference from NO2, if the latter gas concentration does not exceed 20% in a NOx mixture over a range of 100–800 ppm. Since this range constitutes most of the range of total NOx concentrations in diesel and other lean burn engines, this sensor should find application in selective detection of NO in this combustion application. A limitation of this sensor is the interference with CO, but with combustion in excess air, this problem should be alleviated.

  5. Evaluation of catalytic combustion of actual coal-derived gas

    Science.gov (United States)

    Blanton, J. C.; Shisler, R. A.

    1982-01-01

    The combustion characteristics of a Pt-Pl catalytic reactor burning coal-derived, low-Btu gas were investigated. A large matrix of test conditions was explored involving variations in fuel/air inlet temperature and velocity, reactor pressure, and combustor exit temperature. Other data recorded included fuel gas composition, reactor temperatures, and exhaust emissions. Operating experience with the reactor was satisfactory. Combustion efficiencies were quite high (over 95 percent) over most of the operating range. Emissions of NOx were quite high (up to 500 ppm V and greater), owing to the high ammonia content of the fuel gas.

  6. Geopolymer based catalysts-New group of catalytic materials

    Czech Academy of Sciences Publication Activity Database

    Sazama, Petr; Bortnovsky, O.; Dědeček, Jiří; Tvarůžková, Zdenka; Sobalík, Zdeněk

    2011-01-01

    Roč. 164, č. 1 (2011), s. 92-99 ISSN 0920-5861. [Joint International Conference /1./ of the Tokyo Conference on Advanced Catalytic Science and Technology /11./ Asia Pacific Congress on Catalysis /5./. Sapporo, 18.07.2010-23.07.2010] R&D Projects: GA MPO FT-TA4/068; GA AV ČR KAN100400702 Institutional research plan: CEZ:AV0Z40400503 Keywords : geopolymers * redox catalysis * SCR- NOx Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.407, year: 2011

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

    Science.gov (United States)

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

    2013-07-16

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

  8. Phosphorylation of Ser-525 in βPix impairs Nox1-activating ability in Caco-2 cells.

    Science.gov (United States)

    Kaito, Yuuki; Kataoka, Ryosuke; Mihara, Tatsuya; Takechi, Kento; Takahira, Akira; Watanabe, Shuhei; Han, Fei; Tamura, Minoru

    2018-01-15

    βPix activates Nox1, an O 2 - -generating NADPH oxidase, through Rac activation. In this study, we found that S525E mutation of βPix eliminated its Nox1-activating ability in transfected Caco-2 cells. Unexpectedly, affinity for Rac was not diminished but rather enhanced by S525E mutation, and guanine nucleotide exchange factor (GEF) activity was not altered. The N-terminal fragment (amino acids 1-400) showed similar Rac-binding and GEF activity to wild-type βPix. In contrast, the C-terminal fragment (amino acids 408-646) had higher Rac-binding activity, particularly for Rac-GTP, than wild-type βPix, and showed no GEF activity. These data suggest that a second Rac-binding site within the C-terminal region is opened by phosphorylation of Ser-525. The site may bind not only Rac-GDP but also Rac-GTP released from the N-terminal catalytic region, which interrupts Rac-GTP translocation to the membrane where Nox1 resides. If one considers that S340E mutation enhances Nox1 activation (Kaito et al., 2014), the present study suggests that βPix can also play an inhibitory role in O 2 - production, depending on the sites of phosphorylation. Copyright © 2017 Elsevier Inc. All rights reserved.

  9. Nitrogen Oxides (NOx) Primary NAAQS REVIEW: Integrated ...

    Science.gov (United States)

    The NOx Integrated Review Plan is the first document generated as part of the National Ambient Air Quality Standards (NAAQS) review process. The Plan presents background information, the schedule for the review, the process to be used in conducting the review, and the key policy-relevant science issues that will guide the review. The integrated review plan also discusses the frameworks for the various assessment documents to be prepared by the EPA as part of the review, including an Integrated Science Assessment (ISA), and as warranted, a Risk/Exposure Assessment (REA), and a Policy Assessment (PA). The primary purpose of the NOx Integrated Review Plan is to highlight the key policy-relevant issues to be considered in the Review of the NO2 primary NAAQS. A draft of the integrated review plan will be the subject of an advisory review with the Clean Air Scientific Advisory Committee (CASAC) and made available to the public for review and comment.

  10. Non-thermal-plasma-activated de-NOx catalysis.

    Science.gov (United States)

    Gholami, Rahman; Stere, Cristina E; Goguet, Alexandre; Hardacre, Christopher

    2018-01-13

    The combination of non-thermal plasma (NTP) with catalyst systems as an alternative technology to remove NO x emissions in the exhaust of lean-burn stationary and mobile sources is reviewed. Several factors, such as low exhaust gas temperatures (below 300°C), low selectivity to N 2 and the presence of impurities, make current thermally activated technologies inefficient. Various hybrid plasma-catalyst systems have been examined and shown to have a synergistic effect on de-NO x efficiency when compared with NTP or catalyst-alone systems. The NTP is believed to form oxygenated species, such as aldehydes and nitrogen-containing organic species, and to convert NO to NO 2 , which improves the reduction efficiency of N 2 during hydrocarbon-selective catalytic reduction reactions. The NTP has been used as a pretreatment to convert NO to its higher oxidation states such as NO 2 to improve NO x reduction efficiency in the subsequent processes, e.g. NH 3 -selective catalytic reduction. It has been applied to the lean phase of the NO x storage to improve the adsorption capacity of the catalyst by conversion of NO to NO 2 Alternatively, a catalyst with high adsorption capacity is chosen and the NTP is applied to the rich phase to improve the reduction activity of the catalyst at low temperature.This article is part of a discussion meeting issue 'Providing sustainable catalytic solutions for a rapidly changing world'. © 2017 The Author(s).

  11. Catalytic oxidation for treatment of ECLSS and PMMS waste streams

    Science.gov (United States)

    Akse, James R.; Jolly, Clifford D.

    1991-01-01

    It is shown that catalytic oxidation is an effective technique for the removal of trace organic contaminants in a multifiltration potable processor's effluent. Essential elements of this technology are devices that deliver oxygen to the influent, and remove gaseous reaction byproducts from the effluent, via hollow-tube, gas-permeable membranes. Iodine, which poisons existing catalysis, is removed by a small deiodination bed prior to catalytic reactor entrance. The catalyst used is a mixture of Pt and Ru deposited on carbon, operating at 125-160 C and 39-90 psi pressures.

  12. Understanding NOx emission trends in China based on OMI observations

    Science.gov (United States)

    Wang, Y.; Ga, D.; Smeltzer, C. D.; Yi, R.; Liu, Z.

    2012-12-01

    We analyze OMI observations of NO2 columns over China from 2005 to 2010. Simulations using a regional 3-D chemical transport model (REAM) are used to derive the top-down anthropogenic NOx emissions. The Kendall method is then applied to derive the emission trend. The emission trend is affected by the economic slowdown in 2009. After removing the effect of one year abnormal data, the overall emission trend is 4.35±1.42% per year, which is slower than the linear-regression trend of 5.8-10.8% per year reported for previous years. We find large regional, seasonal, and urban-rural variations in emission trend. The annual emission trends of Northeast China, Central China Plain, Yangtze River Delta and Pearl River Delta are 44.98±1.39%, 5.24±1.63%, 3.31±1.02% and -4.02±1.87%, respectively. The annual emission trends of four megacities, Beijing, Shanghai, Guangzhou and Shenzhen are 0.7±0.27%, -0.75±0.31%, -4.08±1.21% and -6.22±2.85%,, considerably lower than the regional averages. These results appear to suggest that a number of factors, including migration of high-emission industries, vehicle emission regulations, emission control measures of thermal power plants, increased hydro-power usage, have reduced or reversed the increasing trend of NOx emissions in more economically developed megacities and southern coastal regions.

  13. Factors Influencing Surface Emissions of CO and NOx From a Brazilian Savanna

    Science.gov (United States)

    Zepp, R. G.; Kisselle, K. W.; Burke, R. A.; Pinto, A. S.; Bustamante, M. M.

    2002-12-01

    Human activities in savannas such as biomass burning and land conversion influence soil and plant emissions of atmospheric carbon monoxide (CO) and NOx [nitric oxide (NO) plus nitrogen dioxide (NO2)]. Direct emissions of these gases from burning are a major global source. In addition, emissions of CO and NOX from soils and plant litter also provide a significant source of the gases. Here, we report field and laboratory investigations of the production of CO and NOx from soils and surface litter derived from two natural vegetation types in central Brazil, cerrado stricto sensu (20-50% canopy cover) and campo sujo (open scrubland). The field studies were conducted using opaque and transparent flux chambers to investigate the effects of illumination and heating of the land surface on the gas fluxes. These studies showed that both NOx and CO fluxes were elevated in the transparent chambers. The largest increases in NOx and CO fluxes were observed from recently burned surfaces, indicating that photochemical or temperature-sensitive precursors of the gases were produced in the surface residue by fire. Laboratory studies of the thermal production of CO from plant litter were species specific with activation energies ranging from 72 to 100 kJ mol-1. Activation energies for deciduous plant litter from the Brazilian sites were higher than those previously reported for African savanna grass litter. Other laboratory studies using simulated solar radiation demonstrated that removal of UV radiation by light filters strongly reduced CO fluxes, indicating that the observed enhancement of CO production under illumination was primarily due to photodegradation of the litter rather than enhanced thermal production.

  14. Characteristics of Pt-K/MgAl2O4 lean NOx trap catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Do Heui; Mudiyanselage, Kumudu K.; Szanyi, Janos; Zhu, Haiyang; Kwak, Ja Hun; Peden, Charles HF

    2012-04-30

    We report the various characteristics of Pt-K/MgAl{sub 2}O{sub 4} lean NOx trap (LNT) catalysts including the effect of K loading on nitrate formation/decomposition, NOx storage activity and durability. Upon the adsorption of NO{sub 2} on K/MgAl{sub 2}O{sub 4} samples, potassium nitrates formed on Mg-related sites in MgAl{sub 2}O{sub 4} support are observed, in addition to the typical two potassium nitrates (ionic and bidentate) formed also on Al{sub 2}O{sub 3} supported sample. Based on NO{sub 2} TPD and FTIR results, the Mg-bound KNO{sub 3} thermally decompose at higher temperature than Al-bound KNO{sub 3}, implying its superior thermal stability. At a potassium loading of 5wt%, the temperature of maximum NOx uptake (T{sub max}) is 300 C. Increasing the potassium loading from 5wt% to 10 wt%, the T{sub max} gradually shifted from 300 C to 450 C, indicating the dependence of T{sub max} on the potassium loading. However, increase in potassium loading above 10 wt% only gives rise to the reduction in the overall NOx storage capacity. This work also underlines the obstacles these materials have prior to their practical application (e.g., durability and sulfur poisoning/ removal). This work provides fundamental understanding of Pt-K/MgAl{sub 2}O{sub 4}-based lean NOx trap catalysts, which could be good candidates for high temperature LNT applications.

  15. Diurnal variation of NOx and ozone exchange between a street canyon and the overlying air

    Science.gov (United States)

    Kwak, Kyung-Hwan; Baik, Jong-Jin

    2014-04-01

    The diurnal variation of NOx and O3 exchange between a street canyon and the overlying air in two dimensions is investigated to understand reactive pollutant removal and entrainment across the roof level of the street canyon. The computational fluid dynamics (CFD) model used in this study is a Reynolds-averaged Navier-Stokes equations (RANS) model and includes the urban surface and radiation processes and the comprehensive chemical processes. The CFD model is used for the one-day simulation in which the easterly ambient wind blows perpendicular to the north-south oriented street canyon with a canyon aspect ratio of 1. In the morning when the surface temperature of the downwind building wall is higher than that of the upwind building wall, two counter-rotating vortices appear in the street canyon (flow regime II). In the afternoon when the surface temperature of the upwind building wall is higher than that of the downwind building wall, an intensified primary vortex appears in the street canyon (flow regime I). The NOx and O3 exchange is generally active in the region close to the building wall with the higher temperature regardless of flow regime. The NOx and O3 exchange by turbulent flow is dominant in flow regime II, whereas the NOx and O3 exchange by mean flow becomes comparable to that by turbulent flow in a certain period of flow regime I. The NOx and O3 exchange velocities are similar to each other in the early morning, whereas these are significantly different from each other around noon and in the afternoon. This behavior indicates that the exchange velocity is dependent on flow regime. In addition, the diurnal variability of O3 exchange velocity is found to be dependent on photochemistry rather than dry deposition in the street canyon. This study suggests that photochemistry as well as flow in a street canyon is needed to be taken into account when exchange velocities for reactive pollutants are estimated.

  16. Toxic Gas Removal by Dielectric Discharge with Corona Effect

    International Nuclear Information System (INIS)

    Moreno, H.; Pacheco, M.; Mercado, A.; Cruz, A.; Pacheco, J.; Yousfi, M.; Eichwald, O.; Benhenni, M.

    2006-01-01

    In this work, a theoretical and experimental study on SO2 and NOx removal by non-thermal plasma technology, more specifically a dielectric barrier (DBD) discharge combined with the Corona effect, is presented. Results obtained from a theoretical study describe the chemical kinetic model of SO2 and NOx removal processes; the effect of OH radicals in removal of both gases is noteworthy. Experimental results of de-SO2 process are reported. Also, optical emission spectroscopy study was applied on some atomic helium lines to obtain temperature of electrons in the non-thermal plasma

  17. Catalytic Functions of Standards

    NARCIS (Netherlands)

    K. Blind (Knut)

    2009-01-01

    textabstractThe three different areas and the examples have illustrated several catalytic functions of standards for innovation. First, the standardisation process reduces the time to market of inventions, research results and innovative technologies. Second, standards themselves promote the

  18. Comparison of Three Bed Packings for the Biological Removal of Nitric Oxide from Gas Streams

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Brady Douglas; Flanagan, W. P.; Barnes, Charles Marshall; Barrett, Karen B.; Zaccardi, Larry Bryan; Apel, William Arnold

    2000-10-01

    Environmental and health issues coupled with increasingly stringent nitrogen oxide (NOx) emission standards indicates a need for the development of alternative low-cost technologies for the removal of NOx from gas streams. Biological NOx conversion offers promise as a novel treatment method. Thermophilic denitrifying bacteria indigenous to composts and soils are capable of converting NOx to environmentally benign nitrogen via a dissimilatory reductive pathway. The present study compares the performance of three bioreactor packing materials (compost, perlite, and biofoam) for the removal of nitric oxide (NO) from a simulated wet-scrubbed combustion gas. Although all three materials performed well (>85% NO removal) at residence times of 70-80 seconds, the compost performed better than the other materials at shorter residence times (13-44 seconds). The perlite and biofoam materials, however, both offer long-term thermal stability and lower pressure drop compared with compost. The feasibility of biological NOx conversion processes will depend on the combined factors of NOx removal ability and pressure drop. The results presented here suggest that the compost, perlite and biofoam systems, subject to further optimization, offer potential for the biological removal of NOx from gas streams.

  19. Lightning NOx Emissions: Reconciling Measured and Modeled Estimates With Updated NOx Chemistry

    Science.gov (United States)

    Nault, B. A.; Laughner, J. L.; Wooldridge, P. J.; Crounse, J. D.; Dibb, J.; Diskin, G.; Peischl, J.; Podolske, J. R.; Pollack, I. B.; Ryerson, T. B.; Scheuer, E.; Wennberg, P. O.; Cohen, R. C.

    2017-09-01

    Lightning is one of the most important sources of upper tropospheric NOx; however, there is a large spread in estimates of the global emission rates (2-8 Tg N yr-1). We combine upper tropospheric in situ observations from the Deep Convective Clouds and Chemistry (DC3) experiment and global satellite-retrieved NO2 tropospheric column densities to constrain mean lightning NOx (LNOx) emissions per flash. Insights from DC3 indicate that the NOx lifetime is 3 h in the region of outflow of thunderstorms, mainly due to production of methyl peroxy nitrate and alkyl and multifunctional nitrates. The lifetime then increases farther downwind from the region of outflow. Reinterpreting previous analyses using the 3 h lifetime reduces the spread among various methods that have been used to calculate mean LNOx emissions per flash and indicates a global LNOx emission rate of 9 Tg N yr-1, a flux larger than the high end of recent estimates.

  20. Catalytic distillation structure

    Science.gov (United States)

    Smith, L.A. Jr.

    1984-04-17

    Catalytic distillation structure is described for use in reaction distillation columns, and provides reaction sites and distillation structure consisting of a catalyst component and a resilient component intimately associated therewith. The resilient component has at least about 70 volume % open space and is present with the catalyst component in an amount such that the catalytic distillation structure consists of at least 10 volume % open space. 10 figs.

  1. The NOX Family of Proteins Is Also Present in Bacteria.

    Science.gov (United States)

    Hajjar, Christine; Cherrier, Mickaël V; Dias Mirandela, Gaëtan; Petit-Hartlein, Isabelle; Stasia, Marie José; Fontecilla-Camps, Juan C; Fieschi, Franck; Dupuy, Jérôme

    2017-11-07

    Transmembrane NADPH oxidase (NOX) enzymes have been so far only characterized in eukaryotes. In most of these organisms, they reduce molecular oxygen to superoxide and, depending on the presence of additional domains, are called NOX or dual oxidases (DUOX). Reactive oxygen species (ROS), including superoxide, have been traditionally considered accidental toxic by-products of aerobic metabolism. However, during the last decade it has become evident that both O 2 •- and H 2 O 2 are key players in complex signaling networks and defense. A well-studied example is the production of O 2 •- during the bactericidal respiratory burst of phagocytes; this production is catalyzed by NOX2. Here, we devised and applied a novel algorithm to search for additional NOX genes in genomic databases. This procedure allowed us to discover approximately 23% new sequences from bacteria (in relation to the number of NOX-related sequences identified by the authors) that we have added to the existing eukaryotic NOX family and have used to build an expanded phylogenetic tree. We cloned and overexpressed the identified nox gene from Streptococcus pneumoniae and confirmed that it codes for an NADPH oxidase. The membrane of the S. pneumoniae NOX protein (SpNOX) shares many properties with its eukaryotic counterparts, such as affinity for NADPH and flavin adenine dinucleotide, superoxide dismutase and diphenylene iodonium inhibition, cyanide resistance, oxygen consumption, and superoxide production. Traditionally, NOX enzymes in eukaryotes are related to functions linked to multicellularity. Thus, the discovery of a large family of NOX-related enzymes in the bacterial world brings up fascinating questions regarding their role in this new biological context. IMPORTANCE NADPH oxidase (NOX) enzymes have not yet been reported in bacteria. Here, we carried out computational and experimental studies to provide the first characterization of a prokaryotic NOX. Out of 996 prokaryotic proteins showing

  2. Development of selective catalytic oxidation (SCO) for NH{sub 3} and HCN removal from gasification gas; Selektiivisen katalyyttisen hapetusprosessin (SCO) kehittaeminen kaasutuskaasun NH{sub 3}:n ja HCN:n poistoon

    Energy Technology Data Exchange (ETDEWEB)

    Leppaelahti, J.; Koljonen, T.; Heiskanen, K. [VTT Energy, Espoo (Finland)

    1997-10-01

    In gasification, reactive nitrogen compounds (mainly NH{sub 3} and HCN) are formed from fuel nitrogen. If the gas containing NH{sub 3} is burned, a high NO{sub x} emission may be formed. The content of nitrogen compounds of the hot gasification gas could be reduced in Selective Catalytic Oxidation (SCO) process. In this process small amounts of reactive oxidisers are injected into the gas in order to convert NH{sub 3} to N{sub 2}. The utilization of SCO process together with low NO{sub x} burners in advanced gasification power stations might offer an alternative for flue gas treatment technologies like SCR (Selective Catalytic Reduction). In the earlier research, conditions were found, where oxidizers reacted selectively with ammonia in the gasification gas. Highest ammonia reduction took place in the aluminium oxide bed in the presence of NO and O{sub 2}. The aim of this study is to examine the reaction mechanism in order to be able to further evaluate the development possibilities of this kind process. The effect of composition and the amount of added oxidizer, the content of combustible gas components, space velocity, pressure and temperature will be studied. The experiments are carried out with the laboratory scale high pressure flow reactor of VTT Energy. Kinetic modelling of the experimental results is carried out in co-operation with the combustion chemistry group of Aabo Akademi. The aim of the modelling work is to bring insight to the gas-phase reactions that are important for the SCO-process. (orig.)

  3. Critical roles for p22phox in the structural maturation and subcellular targeting of Nox3

    OpenAIRE

    Nakano, Yoko; Banfi, Botond; Jesaitis, Algirdas J.; Dinauer, Mary C.; Allen, Lee-Ann H.; Nauseef, William M.

    2007-01-01

    Otoconia are small biominerals in the inner ear that are indispensable for the normal perception of gravity and motion. Normal otoconia biogenesis requires Nox3, a Nox (NADPH oxidase) highly expressed in the vestibular system. In HEK-293 cells (human embryonic kidney cells) transfected with the Nox regulatory subunits NoxO1 (Nox organizer 1) and NoxA1 (Nox activator 1), functional murine Nox3 was expressed in the plasma membrane and exhibited a haem spectrum identical with that of Nox2, the e...

  4. Active Component Migration and Catalytic Properties of Nitrogen Modified Composite Catalytic Materials

    Directory of Open Access Journals (Sweden)

    Miaomiao Li

    2018-03-01

    Full Text Available During the catalytic combustion reaction of methane, the migration of the active species on surface facilitates the catalytic reaction, and the element doping can improve the redox performance of the catalyst. Nitrogen-modified perovskite type composite catalysts were prepared by hydrothermal method and then characterized by X-ray diffractometer (XRD, scanning electron microscopy (SEM, Brunauer-Emmett-Teller (BET, temperature-programmed reductions (TPR, and X-ray photoelectron spectra (XPS. The results revealed that nitrogen sources (urea, biuret, melamine, carbohydrazide, and semicarbazide hydrochloride and nitrogen source addition changed the catalytic performance in physical and chemical properties, the migration of reactive species and the catalytic performance. When the addition amount of semicarbazide hydrochloride was three times that of LaCoO3, the composite catalysts had high Co3+/Co2+ (1.39 and Oads/Olat (15.18 and showed the best catalytic performance: the temperatures that are required for achieving methane conversion of 50% and 90% were 277 and 360 °C, which are more effective than noble metal oxides. Moreover, the in situ diffuse reflectance infrared fourier transform spectroscopy (DRIFTS were applied to elucidate the efficient for CH4 removal and also can further explain the surface reaction mechanism of the composite catalyst during the methane catalytic combustion.

  5. Reducción catalítica selectiva de NOx usando nanopartículas de ferritas Cu1-XCoXFe2O4 como catalizador

    Directory of Open Access Journals (Sweden)

    Sarah Briceño1*

    2009-12-01

    Full Text Available Nanostructured catalysts AB2O4 spinel type oxides (A = Co and B = Cu were prepared by the sol-gel self-combustion method using citric acid as precursor. They were characterized by X-ray diffraction (XRD, Scanning Electron Microscopy (SEM, Transmission Electron Microscopy (TEM and Catalytic activity tests, which have proven to be effective for selective catalytic reduction of NOx using hydrocarbon as a reducing agent (SCR-HC in a temperature range 250 - 450 ° C, reaching up to 40% conversion of NO and 100% selectivity towards the formation of N2

  6. Present status and trends in SO2 and NOx emission control regulations in Europe

    International Nuclear Information System (INIS)

    Ellison, W.

    1987-01-01

    1983 West German legislation (GFAVO) calls for retrofitting by 1988 of FGD facilities of a minimum of 85% sulfur dioxide (SO2) removal efficiency, with stack emission no greater than 400 milligrams (mg) per normal cubic meter (Nm 3 ) of flue gas, for new and existing boilers greater than approximately 110 megawatts i.e. MW(e), size. As of 1986, more than 100 FGD systems with greater than 40,000 MW(e) aggregate capacity have been purchased in West Germany alone. 1983 West German legislation requires by 1993 the retrofit addition of approximately 400 more FGD installations aggregating approximately 25,000 MW(e) of capacity on boilers in the size range 35 to 110 MW(e). Stringent West German SO2 legislation in 1983 was followed in 1984 by enactment of very strict new nitrogen oxides (NOx) limits calling for emissions of no more than 200 mg NOx, measured as nitrogen dioxide, NO2, per Nm 3 , approximately 0.16 lb NO2 per million Btu heat input, for existing and new boilers greater than 110 MW(e), size. As of 1986 approximately 50 high-efficiency commercial systems aggregating more than 10,000 MW(e) capacity, most for retrofit addition, have been purchased in West Germany alone, and approximately 30,000 MW(e) of additional NOx removal capacity will be required to be retrofitted by deadlines during the period 1988 to 1990. For comparative purposes a brief description is given of regulations in North America for control of SO2 and NOx emissions from large coal-fired boilers

  7. Numerical Investigation of AdBlue Droplet Evaporation and Thermal Decomposition in the Context of NOx-SCR Using a Multi-Component Evaporation Model

    OpenAIRE

    Nishad, Kaushal; Sadiki, Amsini; Janicka, Johannes

    2018-01-01

    To cope with the progressive tightening of the emission regulations, gasoline and diesel engines will continuously require highly improved exhaust after-treatment systems. In the case of diesel engines, the selective catalytic reduction (SCR) appears as one of the widely adopted technologies to reduce NOx (nitrogen oxides) emissions. Thereby, with the help of available heat from exhaust gas, the injected urea–water solution (UWS) turns inside the exhaust port immediately into gaseous ammonia ...

  8. 40 CFR 96.85 - NOX Budget opt-in permit contents.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false NOX Budget opt-in permit contents. 96... (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS FOR STATE IMPLEMENTATION PLANS Individual Unit Opt-ins § 96.85 NOX Budget opt-in permit contents. (a) Each NOX Budget opt-in permit...

  9. 40 CFR 96.24 - Effective date of initial NOX Budget permit.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Effective date of initial NOX Budget... PROGRAMS (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS FOR STATE IMPLEMENTATION PLANS Permits § 96.24 Effective date of initial NOX Budget permit. The initial NOX Budget permit...

  10. 40 CFR 97.85 - NOX Budget opt-in permit contents.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false NOX Budget opt-in permit contents. 97... (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS Individual Unit Opt-ins. § 97.85 NOX Budget opt-in permit contents. (a) Each NOX Budget opt-in permit will contain all elements...

  11. NOX Activation by Subunit Interaction and Underlying Mechanisms in Disease.

    Science.gov (United States)

    Rastogi, Radhika; Geng, Xiaokun; Li, Fengwu; Ding, Yuchuan

    2016-01-01

    Nicotinamide adenine dinucleotide phosphate (NAPDH) oxidase (NOX) is an enzyme complex with the sole function of producing superoxide anion and reactive oxygen species (ROS) at the expense of NADPH. Vital to the immune system as well as cellular signaling, NOX is also involved in the pathologies of a wide variety of disease states. Particularly, it is an integral player in many neurological diseases, including stroke, TBI, and neurodegenerative diseases. Pathologically, NOX produces an excessive amount of ROS that exceed the body's antioxidant ability to neutralize them, leading to oxidative stress and aberrant signaling. This prevalence makes it an attractive therapeutic target and as such, NOX inhibitors have been studied and developed to counter NOX's deleterious effects. However, recent studies of NOX have created a better understanding of the NOX complex. Comprised of independent cytosolic subunits, p47- phox , p67- phox , p40- phox and Rac , and membrane subunits, gp91- phox and p22- phox , the NOX complex requires a unique activation process through subunit interaction. Of these subunits, p47- phox plays the most important role in activation, binding and translocating the cytosolic subunits to the membrane and anchoring to p22- phox to organize the complex for NOX activation and function. Moreover, these interactions, particularly that between p47- phox and p22- phox , are dependent on phosphorylation initiated by upstream processes involving protein kinase C (PKC). This review will look at these interactions between subunits and with PKC. It will focus on the interaction involving p47- phox with p22- phox , key in bringing the cytosolic subunits to the membrane. Furthermore, the implication of these interactions as a target for NOX inhibitors such as apocynin will be discussed as a potential avenue for further investigation, in order to develop more specific NOX inhibitors based on the inhibition of NOX assembly and activation.

  12. New insights on NOX enzymes in the central nervous system.

    Science.gov (United States)

    Nayernia, Zeynab; Jaquet, Vincent; Krause, Karl-Heinz

    2014-06-10

    There is increasing evidence that the generation of reactive oxygen species (ROS) in the central nervous system (CNS) involves the NOX family of nicotinamide adenine dinucleotide phosphate oxidases. Controlled ROS generation appears necessary for optimal functioning of the CNS through fine-tuning of redox-sensitive signaling pathways, while overshooting ROS generation will lead to oxidative stress and CNS disease. NOX enzymes are not only restricted to microglia (i.e. brain phagocytes) but also expressed in neurons, astrocytes, and the neurovascular system. NOX enzymes are involved in CNS development, neural stem cell biology, and the function of mature neurons. While NOX2 appears to be a major source of pathological oxidative stress in the CNS, other NOX isoforms might also be of importance, for example, NOX4 in stroke. Globally speaking, there is now convincing evidence for a role of NOX enzymes in various neurodegenerative diseases, cerebrovascular diseases, and psychosis-related disorders. The relative importance of specific ROS sources (e.g., NOX enzymes vs. mitochondria; NOX2 vs. NOX4) in different pathological processes needs further investigation. The absence of specific inhibitors limits the possibility to investigate specific therapeutic strategies. The uncritical use of non-specific inhibitors (e.g., apocynin, diphenylene iodonium) and poorly validated antibodies may lead to misleading conclusions. Physiological and pathophysiological studies with cell-type-specific knock-out mice will be necessary to delineate the precise functions of NOX enzymes and their implications in pathomechanisms. The development of CNS-permeant, specific NOX inhibitors will be necessary to advance toward therapeutic applications.

  13. Life cycle assessment of selective non-catalytic reduction (SNCR) of nitrous oxides in a full-scale municipal solid waste incinerator.

    Science.gov (United States)

    Møller, Jacob; Munk, Bjarne; Crillesen, Kim; Christensen, Thomas H

    2011-06-01

    Selective non-catalytic reduction (SNCR) of nitrous oxides in a full-scale municipal solid waste incinerator was investigated using LCA. The relationship between NO(x)-cleaning and ammonia dosage was measured at the plant. Un-reacted ammonia - the ammonia slip - leaving the flue-gas cleaning system adsorbed to fly-ash or in the effluent of the acidic scrubber was quantified from the stoichiometric reaction of NO(x) and ammonia assuming no other reaction products was formed. Of the ammonia slip, 37% was associated with the fly-ash and 63% was in the effluent of the acidic scrubber. Based on NO(x)-cleaning efficiency, the fate of the ammonia slip as well as the environmental impact from ammonia production, the potential acidification and nutrient enrichment from NO(x)-cleaning was calculated as a function of ammonia dosage. Since the exact fate of the ammonia slip could not be measured directly, a number of scenarios were set up ranging from "best case" with no ammonia from the slip ending up in the environment to "worst case" where all the ammonia slip eventually ended up in the environment and contributed to environmental pollution. In the "best case" scenario the highest ammonia dosage was most beneficial demonstrating that the environmental load associated with ammonia production is of minor importance. In contrast, in a "worst case" scenario" NO(x)-cleaning using SNCR is not recommendable at all, since the impacts from the ammonia slip exceed the saved impacts from the NO(x) removal. Increased dosage of ammonia for removal of NO(x) is recommendable as long as less than 10-20% of the ammonia slip to the effluent of the acidic scrubber ends up in the environment and less than 40% of the slip to the fly-ash ends up in the environment. The study suggests that the actual fate of the ammonia slip is crucial, but since the release of the ammonia may take place during transport and at the facilities that treat the wastewater and treat the fly-ash this factor depends

  14. I.C. Engine emission reduction by copper oxide catalytic converter

    Science.gov (United States)

    Venkatesan, S. P.; Shubham Uday, Desai; Karan Hemant, Borana; Rajarshi Kushwanth Goud, Kagita; Lakshmana Kumar, G.; Pavan Kumar, K.

    2017-05-01

    The toxic gases emitted from diesel engines are more than petrol engines. Predicting the use of diesel engines, even more in future, this system is developed and can be used to minimize the harmful gases. Toxic gases include NOX, CO, HC and Smoke which are harmful to the atmosphere as well as to the human beings. The main aim of this work is to fabricate system, where the level of intensity of toxic gases is controlled through chemical reaction to more agreeable level. This system acts itself as an exhaust system; hence there is no needs to fit separate the silencer. The whole assembly is fitted in the exhaust pipe from engine. In this work, catalytic converter with copper oxide as a catalyst, by replacing noble catalysts such as platinum, palladium and rhodium is fabricated and fitted in the engine exhaust. With and without catalytic converter, the experimentations are carried out at different loads such as 0%, 25%, 50%, 75%, and 100% of maximum rated load. From the experimental results it is found that the maximum reduction is 32%, 61% and 21% for HC, NOx and CO respectively at 100% of maximum rated load when compared to that of without catalytic converter. This catalytic converter system is cash effective and more economical than the existing catalytic converter.

  15. Nox family NADPH oxidases: Molecular mechanisms of activation.

    Science.gov (United States)

    Brandes, Ralf P; Weissmann, Norbert; Schröder, Katrin

    2014-11-01

    NADPH oxidases of the Nox family are important enzymatic sources of reactive oxygen species (ROS). Numerous homologue-specific mechanisms control the activity of this enzyme family involving calcium, free fatty acids, protein-protein interactions, intracellular trafficking, and posttranslational modifications such as phosphorylation, acetylation, or sumoylation. After a brief review on the classic pathways of Nox activation, this article will focus on novel mechanisms of homologue-specific activity control and on cell-specific aspects which govern Nox activity. From these findings of the recent years it must be concluded that the activity control of Nox enzymes is much more complex than anticipated. Moreover, depending on the cellular activity state, Nox enzymes are selectively activated or inactivated. The complex upstream signaling aspects of these events make the development of "intelligent" Nox inhibitors plausible, which selectively attenuate disease-related Nox-mediated ROS formation without altering physiological signaling ROS. This approach might be of relevance for Nox-mediated tissue injury in ischemia-reperfusion and inflammation and also for chronic Nox overactivation as present in cancer initiation and cardiovascular disease. Copyright © 2014 Elsevier Inc. All rights reserved.

  16. METHANE de-NOX for Utility PC Boilers

    Energy Technology Data Exchange (ETDEWEB)

    Bruce Bryan; Serguei Nester; Joseph Rabovitser; Stan Wohadlo

    2005-09-30

    The overall project objective is the development and validation of an innovative combustion system, based on a novel coal preheating concept prior to combustion, that can reduce NO{sub x} emissions to 0.15 lb/million Btu or less on utility pulverized coal (PC) boilers. This NO{sub x} reduction should be achieved without loss of boiler efficiency or operating stability, and at more than 25% lower levelized cost than state-of-the-art SCR technology. A further objective is to ready technology for full-scale commercial deployment to meet the market demand for NO{sub x} reduction technologies. Over half of the electric power generated in the U.S. is produced by coal combustion, and more than 80% of these units utilize PC combustion technology. Conventional measures for NOx reduction in PC combustion processes rely on combustion and post-combustion modifications. A variety of combustion-based NO{sub x} reduction technologies are in use today, including low-NO{sub x} burners (LNBs), flue gas recirculation (FGR), air staging, and natural gas or other fuel reburning. Selective non-catalytic reduction (SNCR) and selective catalytic reduction (SCR) are post-combustion techniques. NO{sub x} reduction effectiveness from these technologies ranges from 30 to 60% and up to 90-93% for SCR. Typically, older wall-fired PC burner units produce NO{sub x} emissions in the range of 0.8-1.6 lb/million Btu. Low-NO{sub x} burner systems, using combinations of fuel staging within the burner and air staging by introduction of overfire air in the boiler, can reduce NO{sub x} emissions by 50-60%. This approach alone is not sufficient to meet the desired 0.15 lb/million Btu NO{sub x} standard with a range of coals and boiler loads. Furthermore, the heavy reliance on overfire air can lead to increased slagging and corrosion in furnaces, particularly with higher-sulfur coals, when LNBs are operated at sub-stoichiometric conditions to reduce fuel-derived NOx in the flame. Therefore, it is desirable

  17. Production of activated carbons from waste tyres for low temperature NOx control.

    Science.gov (United States)

    Al-Rahbi, Amal S; Williams, Paul T

    2016-03-01

    Waste tyres were pyrolysed in a bench scale reactor and the product chars were chemically activated with alkali chemical agents, KOH, K2CO3, NaOH and Na2CO3 to produce waste tyre derived activated carbons. The activated carbon products were then examined in terms of their ability to adsorb NOx (NO) at low temperature (25°C) from a simulated industrial process flue gas. This study investigates the influence of surface area and porosity of the carbons produced with the different alkali chemical activating agents on NO capture from the simulated flue gas. The influence of varying the chemical activation conditions on the porous texture and corresponding NO removal from the flue gas was studied. The activated carbon sorbents were characterized in relation to BET surface area, micropore and mesopore volumes and chemical composition. The highest NO removal efficiency for the waste tyre derived activated carbons was ∼75% which was obtained with the adsorbent treated with KOH which correlated with both the highest BET surface area and largest micropore volume. In contrast, the waste tyre derived activated carbons prepared using K2CO3, NaOH and Na2CO3 alkali activating agents appeared to have little influence on NO removal from the flue gases. The results suggest problematic waste tyres, have the potential to be converted to activated carbons with NOx removal efficiency comparable with conventionally produced carbons. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Simultaneous reduction of NOx, N{sub 2}O, SO{sub 2} emissions from a fluidized bed coal combustor using alternative bed material

    Energy Technology Data Exchange (ETDEWEB)

    Shimizu, T.; Asazuma, J.; Shinkai, M.; Matsunaga, S.; Yamagiwa, K.; Fujiwara, N. [Niigata University, Niigata (Japan). Dept. of Chemistry & Chemical Engienering

    2003-07-01

    A kind of porous alumina was employed as bed material of bubbling fluidized bed coal combustion instead of non-porous silica sand. The effect of the bed material on emissions of N{sub 2}O and NOx was evaluated using a bench-scale combustor. The present porous alumina suppressed N{sub 2}O emission. This result is explained by the catalytic activity of porous alumina to decompose N{sub 2}O. In addition, NOx emission with porous bed material was nearly the same as or lower than that for the sand bed. Thus the decrease in N{sub 2}O without increasing NOx was attained. A modification of desulfurization by limestone was proposed. Fine limestone particles were employed as sorbent in order to conduct SO{sub 2} capture in the freeboard. By employing fine particles, the contact between volatile matter and limestone, which is known to increase the emission of NOx, was avoided. Thus the increase in NOx emission during limestone feed was avoided.

  19. THE EFFECT OF IRRADIATION DOSE AND AMMONIA CONCENTRATION ON THE APPLICATION OF ELECTRON BEAM FOR TREATMENT GASES POLLUTION OF SO2AND NOX

    Directory of Open Access Journals (Sweden)

    Erizal Erizal

    2010-06-01

    Full Text Available The application of electron beam for treatment gases pollution of SO2 and NOx has been studied.  The simulated SO2 and NOx gases stream produced from diesel fuel burning boiler were flown into electron beam chamber. Irradiation was conducted using 1000 keV electron beam machine at the dose up to 8.8 kGy, while   water vapour and the ammonia gas with variation concentration flew into the system during irradiation. The concentrations of the gases change were observed during processes. After evaluation, it was found that by increasing irradiation dose, the concentration of SO2 and NOx gases removal increases.  The efficiency of gases removal may reach 98 % for SO2 and 88 % for NOX at a dose of 8.8 kGy. By increasing ammonia concentration, the efficiency gas removal increases. Besides, by-products from the irradiation yield were sulfate and nitrate salt compound which are possible to be used as a fertilizer.      Keywords: radiation, electron beam, gas pollution, SO2, NOx, ammonia

  20. Storage of Nitrous Oxide (NOx in Diesel Engine Exhaust Gas using Alumina-Based Catalysts: Preparation, Characterization, and Testing

    Directory of Open Access Journals (Sweden)

    A. Alsobaai

    2017-03-01

    Full Text Available This work investigated the nitrous oxide (NOx storage process using alumina-based catalysts (K2 O/Al2 O3 , CaO/Al2 O3,  and BaO/Al2 O3 . The feed was a synthetic exhaust gas containing 1,000 ppm of nitrogen monoxide (NO, 1,000 ppm i-C4 H10 , and an 8% O2  and N2  balance. The catalyst was carried out at temperatures between 250–450°C and a contact time of 20 minutes. It was found that NOx was effectively adsorbed in the presence of oxygen. The NOx storage capacity of K2 O/Al2 O3 was higher than that of BaO/Al2 O3.  The NOx storage capacity for K2 O/Al2 O3  decreased with increasing temperature and achieved a maximum at 250°C. Potassium loading higher than 15% in the catalyst negatively affected the morphological properties. The combination of Ba and K loading in the catalyst led to an improvement in the catalytic activity compared to its single metal catalysts. As a conclusion, mixed metal oxide was a potential catalyst for de-NOx process in meeting the stringent diesel engine exhaust emissions regulations. The catalysts were characterized by a number of techniques and measurements, such as X-ray diffraction (XRD, electron affinity (EA, a scanning electron microscope (SEM, Brunner-Emmett-Teller (BET to measure surface area, and pore volume and pore size distribution assessments.

  1. Analysis of NOx Budget Trading Program Units Brought into the CAIR NOx Ozone Season Trading Program

    Science.gov (United States)

    EPA analyzed the effect of having the large non-EGU units in the NBP and the CAIR NOX ozone season trading program and evaluated whether or not emissions from this group of units were reduced as a result of their inclusion in those trading programs.

  2. Method for recovering catalytic elements from fuel cell membrane electrode assemblies

    Science.gov (United States)

    Shore, Lawrence [Edison, NJ; Matlin, Ramail [Berkeley Heights, NJ; Heinz, Robert [Ludwigshafen, DE

    2012-06-26

    A method for recovering catalytic elements from a fuel cell membrane electrode assembly is provided. The method includes converting the membrane electrode assembly into a particulate material, wetting the particulate material, forming a slurry comprising the wetted particulate material and an acid leachate adapted to dissolve at least one of the catalytic elements into a soluble catalytic element salt, separating the slurry into a depleted particulate material and a supernatant containing the catalytic element salt, and washing the depleted particulate material to remove any catalytic element salt retained within pores in the depleted particulate material.

  3. Deficiency of NOX1 or NOX4 Prevents Liver Inflammation and Fibrosis in Mice through Inhibition of Hepatic Stellate Cell Activation.

    Directory of Open Access Journals (Sweden)

    Tian Lan

    Full Text Available Reactive oxygen species (ROS produced by nicotinamide adenine dinucleotide phosphate oxidase (NOX play a key role in liver injury and fibrosis. Previous studies demonstrated that GKT137831, a dual NOX1/4 inhibitor, attenuated liver fibrosis in mice as well as pro-fibrotic genes in hepatic stellate cells (HSCs as well as hepatocyte apoptosis. The effect of NOX1 and NOX4 deficiency in liver fibrosis is unclear, and has never been directly compared. HSCs are the primary myofibroblasts in the pathogenesis of liver fibrosis. Therefore, we aimed to determine the role of NOX1 and NOX4 in liver fibrosis, and investigated whether NOX1 and NOX4 signaling mediates liver fibrosis by regulating HSC activation. Mice were treated with carbon tetrachloride (CCl4 to induce liver fibrosis. Deficiency of either NOX1 or NOX4 attenuates liver injury, inflammation, and fibrosis after CCl4 compared to wild-type mice. NOX1 or NOX4 deficiency reduced lipid peroxidation and ROS production in mice with liver fibrosis. NOX1 and NOX4 deficiency are approximately equally effective in preventing liver injury in the mice. The NOX1/4 dual inhibitor GKT137831 suppressed ROS production as well as inflammatory and proliferative genes induced by lipopolysaccharide (LPS, platelet-derived growth factor (PDGF, or sonic hedgehog (Shh in primary mouse HSCs. Furthermore, the mRNAs of proliferative and pro-fibrotic genes were downregulated in NOX1 and NOX4 knock-out activated HSCs (cultured on plastic for 5 days. Finally, NOX1 and NOX4 protein levels were increased in human livers with cirrhosis compared with normal controls. Thus, NOX1 and NOX4 signaling mediates the pathogenesis of liver fibrosis, including the direct activation of HSC.

  4. Conference: the wet catalytic oxidation, a technology for the removal of organic pollutants in industrial waters; Conference: l'oxydation voie humide catalytique, une technologie pour l'elimination des polluants organiques dans les eaux industrielles

    Energy Technology Data Exchange (ETDEWEB)

    Besson, M. [Institut de recherches sur la catalyse - CNRS, 2 avenue Albert Einstein, 69626 Villeurbanne Cedex (France)

    2004-07-01

    In this conference, it is taken stock on the use of catalysts in the wet oxidation process. Supported (TiO{sub 2}, ZrO{sub 2}....) heterogeneous metallic catalysts (Pt, Ru...) are particularly studied. It is shown that this type of catalysts can answer to the required characteristics: activity for the removal of organic matter, lack of active metal leaching in aqueous acid medium, no deactivation...Examples are given. (O.M.)

  5. Effect of exhaust gases of Exhaust Gas Recirculation (EGR) coupling lean-burn gasoline engine on NOx purification of Lean NOx trap (LNT)

    Science.gov (United States)

    Liu, Lei; Li, Zhijun; Liu, Shiyu; Shen, Boxi

    2017-03-01

    Based on pervious experimental research on the application of Exhaust Gas Recirculation (EGR) and Lean NOx Trap (LNT) with its effects on NOx emission control and secondary development of CHEMKIN software, an integrated NOx purification chemical kinetics mechanism including NOx adsorption, NOx desorption and NOx reduction process of LNT was created based on actual exhaust gases of the lean-burn gasoline engine. The effect of exhaust gases on NOx deterioration of LNT was investigated by modifying H2, O2 and overlap phase in mechanism of NOx desorption and NOx reduction process. Research found that the inlet temperature of LNT around 300 °C possesses the best NOx adsorption performance compared with 200 °C and 400 °C. Pt plays an import role in the process of NOx adsorption and NOx reduction. The reductive capability order of complex compound between Pt, and H2, CO and HC is Pt-H2>Pt-CO>Pt-C3H6. Both CO2 and H2O(g) could deteriorate NOx purification of LNT. The deterioration caused by H2O(g) is not significant as CO2 but harder to be regenerated. O2 could be beneficial to the NOx adsorption process, but it also could weaken the reductive atmosphere in the process of NOx desorption and NOx reduction.

  6. The NOX Family of Proteins Is Also Present in Bacteria

    Directory of Open Access Journals (Sweden)

    Christine Hajjar

    2017-11-01

    Full Text Available Transmembrane NADPH oxidase (NOX enzymes have been so far only characterized in eukaryotes. In most of these organisms, they reduce molecular oxygen to superoxide and, depending on the presence of additional domains, are called NOX or dual oxidases (DUOX. Reactive oxygen species (ROS, including superoxide, have been traditionally considered accidental toxic by-products of aerobic metabolism. However, during the last decade it has become evident that both O2•− and H2O2 are key players in complex signaling networks and defense. A well-studied example is the production of O2•− during the bactericidal respiratory burst of phagocytes; this production is catalyzed by NOX2. Here, we devised and applied a novel algorithm to search for additional NOX genes in genomic databases. This procedure allowed us to discover approximately 23% new sequences from bacteria (in relation to the number of NOX-related sequences identified by the authors that we have added to the existing eukaryotic NOX family and have used to build an expanded phylogenetic tree. We cloned and overexpressed the identified nox gene from Streptococcus pneumoniae and confirmed that it codes for an NADPH oxidase. The membrane of the S. pneumoniae NOX protein (SpNOX shares many properties with its eukaryotic counterparts, such as affinity for NADPH and flavin adenine dinucleotide, superoxide dismutase and diphenylene iodonium inhibition, cyanide resistance, oxygen consumption, and superoxide production. Traditionally, NOX enzymes in eukaryotes are related to functions linked to multicellularity. Thus, the discovery of a large family of NOX-related enzymes in the bacterial world brings up fascinating questions regarding their role in this new biological context.

  7. NOx SOx Secondary NAAQS: Integrated Review Plan ...

    Science.gov (United States)

    The NOx SOx Secondary NAAQS Integrated Review Plan is the first document generated as part of the National Ambient Air Quality Standards (NAAQS) review process. The Plan presents background information, the schedule for the review, the process to be used in conducting the review, and the key policy-relevant science issues that will guide the review. The integrated review plan also discusses the frameworks for the various assessment documents to be prepared by the EPA as part of the review, including an Integrated Science Assessment (ISA), and as warranted, a Risk/Exposure Assessment (REA), and a Policy Assessment (PA). The primary purpose of the NOx SOx Secondary NAAQS Integrated Review Plan is to highlight the key policy-relevant issues to be considered in the Review of the Oxides of Nitrogen and Oxides of Sulfur Secondary NAAQS. A draft of the integrated review plan will be the subject of an advisory review with the Clean Air Scientific Advisory Committee (CASAC) and made available to the public for review and comment.

  8. Study on the mechanism of a manganese-based catalyst for catalytic NOX flue gas denitration

    Science.gov (United States)

    Zhang, Lei; Wen, Xin; Lei, Zhang; Gao, Long; Sha, Xiangling; Ma, Zhenhua; He, Huibin; Wang, Yusu; Jia, Yang; Li, Yonghui

    2018-04-01

    Manganese-based bimetallic catalysts were prepared with self-made pyrolysis coke as carrier and its denitration performance of low-temperature SCR (selective catalyst reduction) was studied. The effects of different metal species, calcination temperature, calcination time and the metal load quantity on the denitration performance of the catalyst were studied by orthogonal test. The denitration mechanism of the catalyst was analyzed by XRD (X-ray diffraction), SEM (scanning electron microscope), BET test and transient test. The experiments show that: * The denitration efficiency of Mn-based bimetallic catalysts mainly relates to the metal type, the metal load quantity and the catalyst adjuvant type. * The optimal catalyst preparation conditions are as follows: the load quantity of monometallic MnO2 is 10%, calcined at 300°C for 4h, and then loaded with 8% CeO2, calcined at 350°Cfor 3h. * The denitration mechanism of manganese-based bimetallic oxide catalysts is stated as: NH3 is firstly adsorbed by B acid center Mn-OH which nears Mn4+==O to form NH4+, NH4+ was then attacked by the gas phase NO to form N2, H2O and Mn3+-OH. Finally, Mn3+-OH was oxidized by O2 to regenerate Mn4+.

  9. Modeling Deactivation of Catalysts for Selective Catalytic Reduction of NOx by KCl Aerosols

    DEFF Research Database (Denmark)

    Olsen, Brian Kjærgaard; Castellino, Francesco; Jensen, Anker Degn

    2017-01-01

    A detailed model for the deactivation of a V2O5–WO3/TiO2-based SCR monolith catalyst by potassium poisoning has been developed and validated. The model accounts for deposition of KCl aerosol particles present in the flue gas on the external catalyst surface, the reaction of the deposited particles...... with the catalyst at the surface of the monolith wall, the transport and accumulation of potassium, bound to Brønsted acid sites, throughout the catalyst wall, and the resulting loss in SCR activity. Using an experimentally measured KCl aerosol size distribution as input, the model can replicate the observed...... deactivation rate of a 3 wt % V2O5-7 wt % WO3/TiO2 monolith catalyst, exposed to a KCl aerosol at 350 °C for about 1000 h, as well as the resulting potassium-to-vanadium molar ratios in the catalyst wall. Simulations show that the particle deposition rate, as well as the deactivation rate, decreases...

  10. Steam reformer with catalytic combustor

    Science.gov (United States)

    Voecks, Gerald E. (Inventor)

    1990-01-01

    A steam reformer is disclosed having an annular steam reforming catalyst bed formed by concentric cylinders and having a catalytic combustor located at the center of the innermost cylinder. Fuel is fed into the interior of the catalytic combustor and air is directed at the top of the combustor, creating a catalytic reaction which provides sufficient heat so as to maintain the catalytic reaction in the steam reforming catalyst bed. Alternatively, air is fed into the interior of the catalytic combustor and a fuel mixture is directed at the top. The catalytic combustor provides enhanced radiant and convective heat transfer to the reformer catalyst bed.

  11. Reaction Mechanism for the Formation of Nitrogen Oxides (NO x ) During Coke Oxidation in Fluidized Catalytic Cracking Units

    KAUST Repository

    Chaparala, Sree Vidya

    2015-06-11

    Fluidized catalytic cracking (FCC) units in refineries process heavy feedstock obtained from crude oil distillation. While cracking feed, catalysts get deactivated due to coke deposition. During catalyst regeneration by burning coke in air, nitrogen oxides (NOx) are formed. The increase in nitrogen content in feed over time has resulted in increased NOx emissions. To predict NOx concentration in flue gas, a reliable model for FCC regenerators is needed that requires comprehensive understanding and accurate kinetics for NOx formation. Based on the nitrogen-containing functional groups on coke, model molecules are selected to study reactions between coke-bound nitrogen and O2 to form NO and NO2 using density functional theory. The reaction kinetics for the proposed pathways are evaluated using transition state theory. It is observed that the addition of O2 on coke is favored only when the free radical is present on the carbon atom instead of nitrogen atom. Thus, NOx formation during coke oxidation does not result from the direct attack by O2 on N atoms of coke, but from the transfer of an O atom to N from a neighboring site. The low activation energies required for NO formation indicate that it is more likely to form than NO2 during coke oxidation. The favorable pathways for NOx formation that can be used in FCC models are identified. Copyright © 2015 Taylor & Francis Group, LLC.

  12. Effect of metal ions doping (M = Ti4+, Sn4+) on the catalytic performance of MnOx/CeO2 catalyst for low temperature selective catalytic reduction of NO with NH3

    Science.gov (United States)

    Xiong, Yan; Tang, Changjin; Dong, Lin

    2015-04-01

    Key Laboratory of Mesoscopic Chemistry of MOE, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, PR China The abatement of nitrogen oxides (NOx) emission from exhaust gases of diesel and stationary sources is a significant challenge for economic and social development. Ceria-based solid solutions were synthesized and used as supports to prepare MnOx/Ce0.8Ti0.2O2 and MnOx/Ce0.8Sn0.2O2 catalysts (Mn/CeTi and Mn/CeSn) for low temperature selective catalytic reduction of NO by NH3 (NH3-SCR). The effects of Ti or Sn doping on the catalytic performance of MnOx/CeO2 catalyst were investigated. Experimental results show that doping of Ti or Sn increases the NO removal efficiency of MnOx/CeO2. The NO conversion of Mn/CeTi catalyst is more than 90 % at temperature window of 175 ~ 300 °C under a gas hour space velocity of 60,000 mL.g-1.h-1. Modified catalysts are also found to exhibit greatly improved resistance to sulfur-poisoning. NH3-TPD results suggest that NH3 desorption on the catalysts is observed over a wide temperature range, due to the variability of adsorbed NH3 species with different thermal stabilities. Doping of Ti and Sn into Mn/CeO2 greatly increased the NH3 adsorption ability of the composites which could promote the SCR reaction. Characterization results also indicate that doping of Ti or Sn brings about catalysts with higher BET surface area, enhanced oxygen storage capacity and increased surface acidity.

  13. DESIGN REPORT: LOW-NOX BURNERS FOR PACKAGE BOILERS

    Science.gov (United States)

    The report describes a low-NOx burner design, presented for residual-oil-fired industrial boilers and boilers cofiring conventional fuels and nitrated hazardous wastes. The burner offers lower NOx emission levels for these applications than conventional commercial burners. The bu...

  14. 40 CFR 60.44 - Standard for nitrogen oxides (NOX).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Standard for nitrogen oxides (NOX). 60.44 Section 60.44 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS... nitrogen oxides (NOX). (a) Except as provided under paragraph (e) of this section, on and after the date on...

  15. NOX Inhibitors - A Promising Avenue for Ischemic Stroke.

    Science.gov (United States)

    Kim, Jong Youl; Park, Joohyun; Lee, Jong Eun; Yenari, Midori A

    2017-08-01

    NADPH-oxidase (NOX) mediated superoxide originally found on leukocytes, but now recognized in several types of cells in the brain. It has been shown to play an important role in the progression of stroke and related cerebrovascular disease. NOX is a multisubunit complex consisting of 2 membrane-associated and 4 cytosolic subunits. NOX activation occurs when cytosolic subunits translocate to the membrane, leading to transport electrons to oxygen, thus producing superoxide. Superoxide produced by NOX is thought to function in long-term potentiation and intercellular signaling, but excessive production is damaging and has been implicated to play an important role in the progression of ischemic brain. Thus, inhibition of NOX activity may prove to be a promising treatment for ischemic brain as well as an adjunctive agent to prevent its secondary complications. There is mounting evidence that NOX inhibition in the ischemic brain is neuroprotective, and targeting NOX in circulating immune cells will also improve outcome. This review will focus on therapeutic effects of NOX assembly inhibitors in brain ischemia and stroke. However, the lack of specificity and toxicities of existing inhibitors are clear hurdles that will need to be overcome before this class of compounds could be translated clinically.

  16. Multiphase catalysts for selective reduction of NOx with hydrocarbons

    NARCIS (Netherlands)

    Maisuls, S.E.

    2000-01-01

    The combustion of fuels, to meet the society demands for energy, result in the emissi of large quantities of nitrogen oxides (NOx) to the environment. These pollutants cause severe environmental problems and present a serious hazard to the health. Nowadays, two methods for the control of NOx

  17. Single bank NOx adsorber for heavy duty diesel engines

    NARCIS (Netherlands)

    Genderen, M. van; Aken, M.G. van

    2003-01-01

    In a NOx adsorber programme the feasibility for applying this technology to heavy duty diesel engines was investigated. After modelling and simulations for realising best λ < 1 engine conditions a platform was build which was used to obtain good NOx adsorber regeneration settings in a number of

  18. NOx reduction by ozone injection and direct plasma treatment

    DEFF Research Database (Denmark)

    Stamate, Eugen; Salewski, Mirko

    2012-01-01

    NOx reduction by ozone injection and direct plasma treatment is investigated for different process parameters in a 6 m long serpentine reactor. Several aspects including the role of mixing scheme, water vapours, steep temperature gradient and time dependet NOx levels are taken into consideration...

  19. Myocardin-related transcription factor regulates Nox4 protein expression

    DEFF Research Database (Denmark)

    Rozycki, Matthew; Bialik, Janne Folke; Speight, Pam

    2016-01-01

    TGFβ-induced expression of the NADPH oxidase Nox4 is essential for fibroblast-myofibroblast transition. Rho has been implicated in Nox4 regulation, but the underlying mechanisms are largely unknown. Myocardin-related transcription factor (MRTF), a Rho/actin polymerization-controlled coactivator o...

  20. NOx photocatalytic degradation employing concrete pavement containing titanium dioxide

    NARCIS (Netherlands)

    Ballari, M.M.; Hunger, Martin; Hüsken, Götz; Brouwers, Jos

    2010-01-01

    In the present work the degradation of nitrogen oxides (NOx) by concrete paving stones containing TiO2 to be applied in road construction is studied. A kinetic model is proposed to describe the photocatalytic reaction of NOx (combining the degradation of NO and the appearance and disappearance of

  1. Plume Evolution and NOx Lifetime in the Denver Metropolitan Area

    Science.gov (United States)

    Ebben, C. J.; Sparks, T.; Wooldridge, P. J.; Cohen, R. C.

    2016-12-01

    NOx (NOx≡NO+NO2) is abundant in urban areas due to its emission via combustion processes. As NOx is transported away from cities, it undergoes photochemical oxidation to produce a variety of nitrogen oxide products, including peroxynitrates (PNs), alkyl nitrates (ANs), and nitric acid (HNO3). These species have different loss mechanisms and lifetimes, meaning that ongoing nitrogen oxide chemistry may differ greatly in the near- and far-field of cities. Understanding the evolution of NOx and NOy (NOy≡NOx+PNs+ANs+HNO3+…) - including the relative balance between NOx oxidation products and their overall concentrations - as air masses are transported away from cities is imperative to constraining the lifetime of NOx and understanding how air quality regulations aimed at lowering NOx emissions might impact air quality in the near- and far-field of urban areas. We have used observations from the Front Range Air Pollution and Photochemistry Experiment (FRAPPÉ) to investigate the evolution of NOx in air masses originating from the Denver urban area, and our results are contrasted with examples from other cities.

  2. [Low-temperature catalytic reduction of NO over Fe-MnOx-CeO2/ZrO2 catalyst].

    Science.gov (United States)

    Liu, Rong; Yang, Zhi-Qin

    2012-06-01

    Fe-MnOx-CeO2/ZrO2 catalysts were prepared through impregnation method with nanometer ZrO2 as a carrier and used in selective catalytic reduction of NO with NH3 at low temperature. Effects of active component ratio and loading of promoter on the catalyst activity were investigated. The catalysts were characterized by means of XRD, SEM, EDS and BET. The effects of temperature, SO2 and H2O on NO conversion were studied and the results showed that in the absence of SO2 and H2O, the catalyst of 8% Fe-10% MnOx-CeO2/ZrO2 had good activity and stability as well as the NOx removal efficiency reached 85.23% at 120 degrees C and 92.0% at 180 degrees C. The presence of SO2 and H2O results in the catalyst deactivated. Properties of the catalyst on different reaction stages were characterized by FT-IR to study the inactivation mechanism of the catalyst. The results showed that the catalyst deactivation was due to the deposition of ammonium sulfate on the catalyst and the sulphation of the catalyst.

  3. Protocatechuic aldehyde attenuates cisplatin-induced acute kidney injury by suppressing Nox-mediated oxidative stress and renal inflammation

    Directory of Open Access Journals (Sweden)

    Li Gao

    2016-12-01

    Full Text Available Cisplatin is a classic chemotherapeutic agent widely used to treat different types of cancers including ovarian, head and neck, testicular and uterine cervical carcinomas. However, cisplatin induces acute kidney injury by directly triggering an excessive inflammatory response, oxidative stress and programmed cell death of renal tubular epithelial cells. All of which lead to higher mortality rates in patients. In this study we examined the protective effect of protocatechuic aldehyde (PA in vitro in cisplatin-treated tubular epithelial cells and in vivo in cisplatin nephropathy. PA is a monomer of Traditional Chinese Medicine isolated from the root of S. miltiorrhiza. Results show that PA prevented cisplatin-induced decline of renal function and histological damage, which was confirmed by attenuation of KIM1 in both mRNA and protein levels. Moreover, PA reduced renal inflammation by suppressing oxidative stress and programmed cell death in response to cisplatin, which was further evidenced by in vitro data. Of note, PA suppressed NAPDH oxidases, including Nox2 and Nox4, in a dosage-dependent manner. Moreover, silencing Nox4, but not Nox2, removed the inhibitory effect of PA on cisplatin-induced renal injury, indicating that Nox4 may play a pivotal role in mediating the protective effect of PA in cisplatin-induced acute kidney injury. Collectively, our data indicate that PA largely blocked cisplatin-induced acute kidney injury by suppressing Nox-mediated oxidative stress and renal inflammation without compromising anti-tumor activity of cisplatin. These findings suggest that PA and its derivatives may serve as potential protective agents for cancer patients with cisplatin treatment.

  4. Co-controlling CO2 and NOx emission in China's cement industry: An optimal development pathway study

    Directory of Open Access Journals (Sweden)

    Xiang-Zhao Feng

    2018-03-01

    Full Text Available It is of important practical significance to reduce NOx emission and CO2 emission in China's cement industry. This paper firstly identifies key factors that influence China's future cement demand, and then uses the Gompertz model to project China's future cement demand and production. Furthermore, the multi-pollutant abatement planning model (MAP was developed based on the TIMES model to analyze the co-benefits of CO2 and NOx control in China's cement industry. During modeling analysis, three scenarios such as basic as usual scenario (BAU, moderately low carbon scenario (MLC, and radically low carbon scenario (RLC, were built according to different policy constraints and emission control goals. Moreover, the benefits of co-controlling NOx and CO2 emission in China's cement industry have been estimated. Finally, this paper proposes a cost-efficient, green, and low carbon development roadmap for the Chinese cement sector, and puts forwards countermeasures as follows: first, different ministries should enhance communication and coordination about how to promote the co-control of NOx and CO2 in cement industry. Second, co-control technology list should be issued timely for cement industry, and the R&D investment on new technologies and demonstration projects should be increased. Third, the phase-out of old cement capacity needs to be continued at policy level. Fourth, it is important to scientifically evaluate the relevant environmental impact and adverse motivation of ammonia production by NOx removal requirement in cement industry. Keywords: Cement industry, CO2 abatement, NOx reduction, Co-benefit analysis

  5. Design and implementation of mixing chambers to improve thermal decomposition of urea for NOX abatement

    KAUST Repository

    Lee, Junggil

    2012-10-01

    Urea-selective catalytic reduction (SCR) has been reported as the most promising technique for adherence to NOX emissions regulations. In the urea-SCR process, NH3 is generated by urea thermal decomposition and hydrolysis and is then used as a reductant of NOX in the SCR catalyst. Therefore, improving the NOX conversion efficiency of urea-SCR requires enhancement of thermal decomposition upstream of the SCR catalyst. In the present work, two types of mixing chambers were designed and fabricated to improve urea thermal decomposition, and experiments with and without a mixing chamber were carried out to analyze thermal-decomposition characteristics of urea in the exhaust pipe with respect to inlet velocity (4-12μm/s) and temperature (350°C-500°C). Urea thermal decomposition is greatly enhanced at higher gas temperatures. At an inlet velocity of 6μm/s in the A-type mixing chamber, NH3 concentrations generated along the exhaust pipe were about 171% and 157% greater than those without the mixing chamber for inlet temperatures of 400°C and 500°C, respectively. In the case of the B-type mixing chamber, NH3 concentrations generated at inlet temperatures of 400°C and 500°C were about 147% and 179% greater than those without the mixing chamber, respectively. Note that the implementation of mixing chambers significantly enhanced conversion of urea to NH3 because it increased the residence time of urea in the exhaust pipe and improved mixing between urea and exhaust gas. © 2012, Mary Ann Liebert, Inc.

  6. Dark chocolate inhibits platelet isoprostanes via NOX2 down-regulation in smokers.

    Science.gov (United States)

    Carnevale, R; Loffredo, L; Pignatelli, P; Nocella, C; Bartimoccia, S; Di Santo, S; Martino, F; Catasca, E; Perri, L; Violi, Francesco

    2012-01-01

    Dark chocolate is reported to decrease platelet activation but the underlying mechanism is still undefined. Dark chocolate is rich in polyphenols that could exert an antiplatelet action via inhibition of oxidative stress. The aim of the present study was to assess if dark chocolate inhibits platelet reactive oxidant species (ROS) formation and platelet activation. Twenty healthy subjects (HS) and 20 smokers were randomly allocated to receive 40 g of dark (cocoa > 85%) or milk chocolate (cocoa chocolate ingestion, platelet recruitment (PR), platelet ROS, platelet isoprostane 8-ISO-prostaglandin F2α (8-iso-PGF2α), Thromboxane (TxA2) and platelet activation of NOX2, the catalytic sub-unit of NADPH oxidase, and serum epicatechin were measured. Compared with HS, smokers showed enhanced PR, platelet formation of ROS and eicosanoids and NOX2 activation. After dark chocolate, platelet ROS (-48%, P chocolate did not affect platelet variables in HS. No effect of milk chocolate was detected in both groups. Serum epicatechin increased after dark chocolate in HS (from 0.454 ± 0.3 nm to 118.3 ± 53.7 nm) and smokers (from 0.5 ± 0.28 nm to 120.9 ± 54.2 nm). Platelet incubation with 0.1-10 μm catechin significantly reduced PR, platelet 8-iso-PGF2α and ROS formation and NOX2 activation only in platelets from smokers. Dark chocolate inhibits platelet function by lowering oxidative stress only in smokers; this effect seems to be dependent on its polyphenolic content. © 2011 International Society on Thrombosis and Haemostasis.

  7. NOx Control Options and Integration for US Coal Fired Boilers

    Energy Technology Data Exchange (ETDEWEB)

    Mike Bockelie; Kevin Davis; Connie Senior Darren Shino; Dave Swenson; Larry Baxter; Calvin Bartholomew; William Hecker; Stan Harding

    2004-09-30

    This is the seventeenth Quarterly Technical Report for DOE Cooperative Agreement No: DEFC26-00NT40753. The goal of the project is to develop cost effective analysis tools and techniques for demonstrating and evaluating low NOx control strategies and their possible impact on boiler performance for boilers firing US coals. The Electric Power Research Institute (EPRI) is providing co-funding for this program. The SCR slipstream reactor was assembled and installed at Plant Gadsden this quarter. Safety equipment for ammonia had not been installed at the end of the quarter, but will be installed at the beginning of next quarter. The reactor will be started up next quarter. Four ECN corrosion probes were reinstalled at Gavin and collected corrosion data for approximately one month. Two additional probes were installed and removed after about 30 hours for future profilometry analysis. Preliminary analysis of the ECN probes, the KEMA coupons and the CFD modeling results all agree with the ultrasonic tube test measurements gathered by AEP personnel.

  8. Verification of NOx emission inventories over North Korea.

    Science.gov (United States)

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

    2014-12-01

    In this study, the top-down NOx emissions estimated from satellite observations of NO2 vertical column densities over North Korea from 1996 to 2009 were analyzed. Also, a bottom-up NOx emission inventory from REAS 1.1 from 1980 to 2005 was analyzed with several statistics. REAS 1.1 was in good agreement with the top-down approach for both trend and amount. The characteristics of NOx emissions in North Korea were quite different from other developed countries including South Korea. In North Korea, emissions from industry sector was the highest followed by transportation sector in the 1980s. However, after 1990, the NOx emissions from other sector, mainly agriculture, became the 2nd highest. Also, no emission centers such as urban areas or industrial areas were distinctively observed. Finally, the monthly NOx emissions were high during the warm season. Copyright © 2014 Elsevier Ltd. All rights reserved.

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

    Energy Technology Data Exchange (ETDEWEB)

    Boyd, Rodney

    2007-08-08

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

  10. CATALYTIC KINETIC SPECTROPHOTOMETRIC DETERMINATION ...

    African Journals Online (AJOL)

    Preferred Customer

    acetylchlorophosphonazo(CPApA) by hydrogen peroxide in 0.10 M phosphoric acid. A novel catalytic kinetic-spectrophotometric method is proposed for the determination of copper based on this principle. Copper(II) can be determined spectrophotometrically ...

  11. CATALYTIC KINETIC SPECTROPHOTOMETRIC DETERMINATION ...

    African Journals Online (AJOL)

    Based on the property that in 0.12 M sulfuric acid medium titanium(IV) catalyzes the discoloring reaction of DBS-arsenazo oxidized by potassium bromate, a new catalytic kinetic spectrophotometric method for the determination of trace titanium (IV) was developed. The linear range of the determination of titanium is

  12. Catalytic hydrogen recombination for nuclear containments

    International Nuclear Information System (INIS)

    Koroll, G.W.; Lau, D.W.P.; Dewit, W.A.; Graham, W.R.C.

    1994-01-01

    Catalytic recombiners appear to be a credible option for hydrogen mitigation in nuclear containments. The passive operation, versatility and ease of back fitting are appealing for existing stations and new designs. Recently, a generation of wet-proofed catalyst materials have been developed at AECL which are highly specific to H 2 -O 2 , are active at ambient temperatures and are being evaluated for containment applications. Two types of catalytic recombiners were evaluated for hydrogen removal in containments based on the AECL catalyst. The first is a catalytic combustor for application in existing air streams such as provided by fans or ventilation systems. The second is an autocatalytic recombiner which uses the enthalpy of reaction to produce natural convective flow over the catalyst elements. Intermediate-scale results obtained in 6 m 3 and 10 m 3 spherical and cylindrical vessels are given to demonstrate self-starting limits, operating limits, removal capacity, scaling parameters, flow resistance, mixing behaviour in the vicinity of an operating recombiner and sensitivity to poisoning, fouling and radiation. (author). 13 refs., 10 figs

  13. Removal of binary dyes mixtures with opposite and similar charges by adsorption, coagulation/flocculation and catalytic oxidation in the presence of CeO2/H2O2 Fenton-like system.

    Science.gov (United States)

    Issa Hamoud, Houeida; Finqueneisel, Gisèle; Azambre, Bruno

    2017-06-15

    In this study, the removal of binary mixtures of dyes with similar (Orange II/Acid Green 25) or opposite charges (Orange II/Malachite Green) was investigated either by simple adsorption on ceria or by the heterogeneous Fenton reaction in presence of H 2 O 2 . First, the CeO 2 nanocatalyst with high specific surface area (269 m 2 /g) and small crystal size (5 nm) was characterized using XRD, Raman spectroscopy and N 2 physisorption at 77 K. The adsorption of single dyes was studied either from thermodynamic and kinetic viewpoints. It is shown that the adsorption of dyes on ceria surface is highly pH-dependent and followed a pseudo-second order kinetic model. Adsorption isotherms fit well the Langmuir model with a complete monolayer coverage and higher affinity towards Orange II at pH 3, compared to other dyes. For the (Orange II/Acid Green 25) mixture, both the amounts of dyes adsorbed on ceria surface and discoloration rates measured from Fenton experiments were decreased by comparison with single dyes. This is due to the adsorption competition existing onto the same surface Ce x+ sites and the reaction competition with hydroxyl radicals, respectively. The behavior of the (Orange II/Malachite Green) mixture is markedly different. Dyes with opposite charges undergo paired adsorption on ceria as well as homogeneous and heterogeneous coagulation/flocculation processes, but can also be removed by heterogeneous Fenton process. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. In-Use NOx Emissions from Diesel and Liquefied Natural Gas Refuse Trucks Equipped with SCR and TWC, Respectively.

    Science.gov (United States)

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

    2017-06-20

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

  15. Catalytic activities of zeolite compounds for decomposing aqueous ozone.

    Science.gov (United States)

    Kusuda, Ai; Kitayama, Mikito; Ohta, Yoshio

    2013-12-01

    The advanced oxidation process (AOP), chemical oxidation using aqueous ozone in the presence of appropriate catalysts to generate highly reactive oxygen species, offers an attractive option for removing poorly biodegradable pollutants. Using the commercial zeolite powders with various Si/Al ratios and crystal structures, their catalytic activities for decomposing aqueous ozone were evaluated by continuously flowing ozone to water containing the zeolite powders. The hydrophilic zeolites (low Si/Al ratio) with alkali cations in the crystal structures were found to possess high catalytic activity for decomposing aqueous ozone. The hydrophobic zeolite compounds (high Si/Al ratio) were found to absorb ozone very well, but to have no catalytic activity for decomposing aqueous ozone. Their catalytic activities were also evaluated by using the fixed bed column method. When alkali cations were removed by acid rinsing or substituted by alkali-earth cations, the catalytic activities was significantly deteriorated. These results suggest that the metal cations on the crystal surface of the hydrophilic zeolite would play a key role for catalytic activity for decomposing aqueous ozone. Copyright © 2013 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.

  16. Molecular cloning and characterization of a tumor-associated, growth-related, and time-keeping hydroquinone (NADH) oxidase (tNOX) of the HeLa cell surface

    Science.gov (United States)

    Chueh, Pin-Ju; Kim, Chinpal; Cho, NaMi; Morre, Dorothy M.; Morre, D. James

    2002-01-01

    NOX proteins are growth-related cell surface proteins that catalyze both hydroquinone or NADH oxidation and protein disulfide interchange and exhibit prion-like properties. The two enzymatic activities alternate to generate a regular period length of about 24 min. Here we report the expression, cloning, and characterization of a tumor-associated NADH oxidase (tNOX). The cDNA sequence of 1830 bp is located on gene Xq25-26 with an open reading frame encoding 610 amino acids. The activities of the bacterially expressed tNOX oscillate with a period length of 22 min as is characteristic of tNOX activities in situ. The activities are inhibited completely by capsaicin, which represents a defining characteristic of tNOX activity. Functional motifs identified by site-directed mutagenesis within the C-terminal portion of the tNOX protein corresponding to the processed plasma membrane-associated form include quinone (capsaicin), copper and adenine nucleotide binding domains, and two cysteines essential for catalytic activity. Four of the six cysteine to alanine replacements retained enzymatic activity, but the period lengths of the oscillations were increased. A single protein with two alternating enzymatic activities indicative of a time-keeping function is unprecedented in the biochemical literature.

  17. Evaluation of NOx Emissions and Modeling

    Science.gov (United States)

    Henderson, B. H.; Simon, H. A.; Timin, B.; Dolwick, P. D.; Owen, R. C.; Eyth, A.; Foley, K.; Toro, C.; Baker, K. R.

    2017-12-01

    Studies focusing on ambient measurements of NOy have concluded that NOx emissions are overestimated and some have attributed the error to the onroad mobile sector. We investigate this conclusion to identify the cause of observed bias. First, we compare DISCOVER-AQ Baltimore ambient measurements to fine-scale modeling with NOy tagged by sector. Sector-based relationships with bias are present, but these are sensitive to simulated vertical mixing. This is evident both in sensitivity to mixing parameterization and the seasonal patterns of bias. We also evaluate observation-based indicators, like CO:NOy ratios, that are commonly used to diagnose emissions inventories. Second, we examine the sensitivity of predicted NOx and NOy to temporal allocation of emissions. We investigate alternative temporal allocations for EGUs without CEMS, on-road mobile, and several non-road categories. These results show some location-specific sensitivity and will lead to some improved temporal allocations. Third, near-road studies have inherently fewer confounding variables, and have been examined for more direct evaluation of emissions and dispersion models. From 2008-2011, the EPA and FHWA conducted near-road studies in Las Vegas and Detroit. These measurements are used to more directly evaluate the emissions and dispersion using site-specific traffic data. In addition, the site-specific emissions are being compared to the emissions used in larger-scale photochemical modeling to identify key discrepancies. These efforts are part of a larger coordinated effort by EPA scientist to ensure the highest quality in emissions and model processes. We look forward to sharing the state of these analyses and expected updates.

  18. Reducing global NOx emissions: developing advanced energy and transportation technologies.

    Science.gov (United States)

    Bradley, Michael J; Jones, Brian M

    2002-03-01

    Globally, energy demand is projected to continue to increase well into the future. As a result, global NOx emissions are projected to continue on an upward trend for the foreseeable future as developing countries increase their standards of living. While the US has experienced improvements in reducing NOx emissions from stationary and mobile sources to reduce ozone, further progress is needed to reduce the health and ecosystem impacts associated with NOx emissions. In other parts of the world, (in developing countries in particular) NOx emissions have been increasing steadily with the growth in demand for electricity and transportation. Advancements in energy and transportation technologies may help avoid this increase in emissions if appropriate policies are implemented. This paper evaluates commercially available power generation and transportation technologies that produce fewer NOx emissions than conventional technologies, and advanced technologies that are on the 10-year commercialization horizon. Various policy approaches will be evaluated which can be implemented on the regional, national and international levels to promote these advanced technologies and ultimately reduce NOx emissions. The concept of the technology leap is offered as a possibility for the developing world to avoid the projected increases in NOx emissions.

  19. Anvil microphysical signatures associated with lightning-produced NOx

    Directory of Open Access Journals (Sweden)

    J. L. Stith

    2016-02-01

    Full Text Available Thunderstorm anvils were studied during the Deep Convective Clouds and Chemistry experiment (DC3, using in situ measurements and observations of ice particles and NOx together with radar and Lightning Mapping Array measurements. A characteristic ice particle and NOx signature was found in the anvils from three storms, each containing high lightning flash rates in the storm core prior to anvil sampling. This signature exhibits high concentrations of frozen droplets (as measured by a Cloud Droplet Probe coincident with lower NOx on the edges of the anvil. The central portion of these anvils exhibited a high degree of aggregation of these frozen droplets and higher levels of NOx. In contrast, a deep convective cell with low lightning flash rates had high concentrations of both frozen droplets and aggregated frozen droplets in its anvil's central region. A conceptual model for these results is presented and applied to the observations from each of these storms. High NOx concentrations are often found where aggregation of frozen droplets has occurred, which may be a reflection of aggregation by electrical forces in the regions where lightning is occurring, although the level of NOx for a given concentration of aggregates varies from storm to storm. These observations between anvil microphysics and lightning and/or NOx signatures suggest that lightning data may be an important tool to characterize or infer the microphysical, radiative, and chemical properties of thunderstorm anvils.

  20. Alternative Splicing of NOX4 in the Failing Human Heart

    Directory of Open Access Journals (Sweden)

    Zoltán V. Varga

    2017-11-01

    Full Text Available Increased oxidative stress is a major contributor to the development and progression of heart failure, however, our knowledge on the role of the distinct NADPH oxidase (NOX isoenzymes, especially on NOX4 is controversial. Therefore, we aimed to characterize NOX4 expression in human samples from healthy and failing hearts. Explanted human heart samples (left and right ventricular, and septal regions were obtained from patients suffering from heart failure of ischemic or dilated origin. Control samples were obtained from donor hearts that were not used for transplantation. Deep RNA sequencing of the cardiac transcriptome indicated extensive alternative splicing of the NOX4 gene in heart failure as compared to samples from healthy donor hearts. Long distance PCR analysis with a universal 5′-3′ end primer pair, allowing amplification of different splice variants, confirmed the presence of the splice variants. To assess translation of the alternatively spliced transcripts we determined protein expression of NOX4 by using a specific antibody recognizing a conserved region in all variants. Western blot analysis showed up-regulation of the full-length NOX4 in ischemic cardiomyopathy samples and confirmed presence of shorter isoforms both in control and failing samples with disease-associated expression pattern. We describe here for the first time that NOX4 undergoes extensive alternative splicing in human hearts which gives rise to the expression of different enzyme isoforms. The full length NOX4 is significantly upregulated in ischemic cardiomyopathy suggesting a role for NOX4 in ROS production during heart failure.

  1. Catalytic thermal barrier coatings

    Science.gov (United States)

    Kulkarni, Anand A.; Campbell, Christian X.; Subramanian, Ramesh

    2009-06-02

    A catalyst element (30) for high temperature applications such as a gas turbine engine. The catalyst element includes a metal substrate such as a tube (32) having a layer of ceramic thermal barrier coating material (34) disposed on the substrate for thermally insulating the metal substrate from a high temperature fuel/air mixture. The ceramic thermal barrier coating material is formed of a crystal structure populated with base elements but with selected sites of the crystal structure being populated by substitute ions selected to allow the ceramic thermal barrier coating material to catalytically react the fuel-air mixture at a higher rate than would the base compound without the ionic substitutions. Precious metal crystallites may be disposed within the crystal structure to allow the ceramic thermal barrier coating material to catalytically react the fuel-air mixture at a lower light-off temperature than would the ceramic thermal barrier coating material without the precious metal crystallites.

  2. Minimising NOx emissions: a symptom of managing change

    Energy Technology Data Exchange (ETDEWEB)

    Howard, J. [UltraMax Corporation (USA)

    2000-07-01

    Minimizing NOx emissions is but a symptom of a bigger issues for utility companies in today's world. The bigger issue is determining how to successfully manage change. The companies that manage change well will solve the environmental issues and solve them profitably. NOx reduction can be achieved. It can be achieved while creating a capability to manage change. Solving the ability to manage change is the best route to take. Reducing NOx can be done but it may create other problems such as increased carbon in ash. The combination of software and hardware solutions have been carefully thought through and efficiently implemented. 7 figs., 2 tabs.

  3. Energy from Waste--clean, efficient, renewable: transitions in combustion efficiency and NOx control.

    Science.gov (United States)

    Waldner, M H; Halter, R; Sigg, A; Brosch, B; Gehrmann, H J; Keunecke, M

    2013-02-01

    Traditionally EfW (Energy from Waste) plants apply a reciprocating grate to combust waste fuel. An integrated steam generator recovers the heat of combustion and converts it to steam for use in a steam turbine/generator set. This is followed by an array of flue gas cleaning technologies to meet regulatory limitations. Modern combustion applies a two-step method using primary air to fuel the combustion process on the grate. This generates a complex mixture of pyrolysis gases, combustion gases and unused combustion air. The post-combustion step in the first pass of the boiler above the grate is intended to "clean up" this mixture by oxidizing unburned gases with secondary air. This paper describes modifications to the combustion process to minimize exhaust gas volumes and the generation of noxious gases and thus improving the overall thermal efficiency of the EfW plant. The resulting process can be coupled with an innovative SNCR (Selective Non-Catalytic Reduction) technology to form a clean and efficient solid waste combustion system. Measurements immediately above the grate show that gas compositions along the grate vary from 10% CO, 5% H(2) and 0% O(2) to essentially unused "pure" air, in good agreement with results from a mathematical model. Introducing these diverse gas compositions to the post combustion process will overwhelm its ability to process all these gas fractions in an optimal manner. Inserting an intermediate step aimed at homogenizing the mixture above the grate has shown to significantly improve the quality of combustion, allowing for optimized process parameters. These measures also resulted in reduced formation of NO(x) (nitrogenous oxides) due to a lower oxygen level at which the combustion process was run (2.6 vol% O(2,)(wet) instead of 6.0 vol% O(2,)(wet)). This reduction establishes optimal conditions for the DyNOR™ (Dynamic NO(x) Reduction) NO(x) reduction process. This innovative SNCR technology is adapted to situations typically

  4. HuR is required for NOX-1 but not NOX-4 regulation by inflammatory stimuli in vascular smooth muscle cells

    Science.gov (United States)

    AGUADO, Andrea; FISCHER, Thierry; RODRÍGUEZ, Cristina; MANEA, Adrian; MARTÍNEZ-GONZÁLEZ, José; TOUYZ, Rhian M.; HERNANZ, Raquel; ALONSO, M. Jesús; DIXON, Dan A.; BRIONES, Ana M.; SALAICES, Mercedes

    2016-01-01

    Objective NOX-1 and NOX-4 are key enzymes responsible for reactive oxygen species (ROS) generation in vascular smooth muscle cells (VSMC). The RNA-binding protein HuR is implicated in post-transcriptional regulation of gene expression; however, its role regulating NOX is unknown. We investigated transcriptional and post-transcriptional mechanisms underlying angiotensinII (AngII) and interleukin-1β (IL-1β) regulation of NOX-1 and NOX-4 in VSMC and their implications in cell migration. Methods Rat and human VSMC were stimulated with AngII (0.1 μM) and/or IL-1β (10 ng/mL). NOX-1 and NOX-4 mRNA and protein levels, NOX-1 and NOX-4 promoter and 3′UTR activities, NADPH oxidase activity, ROS production and cell migration were studied. Results IL-1β increased NOX-1 expression, NADPH oxidase activity and ROS production and decreased NOX-4 expression and H2O2 production in VSMC. AngII potentiated the IL-1β-mediated induction of NOX-1 expression, NADPH oxidase activity, ROS production and cell migration. However, AngII did not influence IL-1β-induced NOX-4 down-regulation. AngII+IL-1β interfered with the decay of NOX-1 mRNA and promoted HuR binding to NOX-1 mRNA. Moreover, HuR blockade reduced NOX-1 mRNA stability and AngII+IL-1β-induced NOX-1 mRNA levels. IL-1β decreased NOX-4 expression through a transcriptional mechanism that involved response elements situated in the proximal promoter. AngII and/or IL-1β-induced cell migration were prevented by NOX-1 and HuR blockade and were augmented by NOX-4 overexpression. Conclusion In VSMC HuR-mediated mRNA stabilization is partially responsible for AngII+IL-1β-dependent NOX-1 expression whereas transcriptional mechanisms are involved in decreased NOX-4 expression induced by IL-1β. NOX4 and HuR regulation of NOX-1 contributes to VSMC migration, important in vascular inflammation and remodeling. PMID:26682942

  5. Hu antigen R is required for NOX-1 but not NOX-4 regulation by inflammatory stimuli in vascular smooth muscle cells.

    Science.gov (United States)

    Aguado, Andrea; Fischer, Thierry; Rodríguez, Cristina; Manea, Adrian; Martínez-González, José; Touyz, Rhian M; Hernanz, Raquel; Alonso, M Jesús; Dixon, Dan A; Briones, Ana M; Salaices, Mercedes

    2016-02-01

    NOX-1 and NOX-4 are key enzymes responsible for reactive oxygen species (ROS) generation in vascular smooth muscle cells (VSMC). The RNA-binding protein Hu antigen R (HuR) is implicated in posttranscriptional regulation of gene expression; however, its role regulating NOX is unknown. We investigated transcriptional and posttranscriptional mechanisms underlying angiotensin II (AngII) and IL-1β regulation of NOX-1 and NOX-4 in VSMC and their implications in cell migration. Rat and human VSMC were stimulated with AngII (0.1 μmol/l) and/or IL-1β (10 ng/ml). NOX-1 and NOX-4 mRNA and protein levels, NOX-1 and NOX-4 promoter and 3'UTR activities, NADPH oxidase activity, ROS production, and cell migration were studied. IL-1β increased NOX-1 expression, NADPH oxidase activity and ROS production, and decreased NOX-4 expression and H2O2 production in VSMC. AngII potentiated the IL-1β-mediated induction of NOX-1 expression, NADPH oxidase activity, ROS production, and cell migration. However, AngII did not influence IL-1β-induced NOX-4 downregulation. AngII + IL-1β interfered with the decay of NOX-1 mRNA and promoted HuR binding to NOX-1 mRNA. Moreover, HuR blockade reduced NOX-1 mRNA stability and AngII + IL-1β-induced NOX-1 mRNA levels. IL-1β decreased NOX-4 expression through a transcriptional mechanism that involved response elements situated in the proximal promoter. AngII and/or IL-1β-induced cell migration were prevented by NOX-1 and HuR blockade and were augmented by NOX-4 overexpression. In VSMC HuR-mediated mRNA stabilization is partially responsible for AngII + IL-1β-dependent NOX-1 expression, whereas transcriptional mechanisms are involved in decreased NOX-4 expression induced by IL-1β. NOX4 and HuR regulation of NOX-1 contributes to VSMC migration, important in vascular inflammation and remodeling.

  6. 40 CFR 1065.670 - NOX intake-air humidity and temperature corrections.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 32 2010-07-01 2010-07-01 false NOX intake-air humidity and... NOX intake-air humidity and temperature corrections. See the standard-setting part to determine if you may correct NOX emissions for the effects of intake-air humidity or temperature. Use the NOX intake...

  7. 40 CFR 96.83 - Applying for NOX Budget opt-in permit.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Applying for NOX Budget opt-in permit... PROGRAMS (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS FOR STATE IMPLEMENTATION PLANS Individual Unit Opt-ins § 96.83 Applying for NOX Budget opt-in permit. (a) Applying for...

  8. 40 CFR 97.83 - Applying for NOX Budget opt-in permit.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Applying for NOX Budget opt-in permit... PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS Individual Unit Opt-ins. § 97.83 Applying for NOX Budget opt-in permit. (a) Applying for initial NO X Budget opt...

  9. 40 CFR 97.88 - NOX allowance allocations to opt-in units.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false NOX allowance allocations to opt-in... PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS Individual Unit Opt-ins. § 97.88 NOX allowance allocations to opt-in units. (a) NO X allotment allocation. (1) By...

  10. 40 CFR 96.88 - NOX allowance allocations to opt-in units.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false NOX allowance allocations to opt-in... PROGRAMS (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS FOR STATE IMPLEMENTATION PLANS Individual Unit Opt-ins § 96.88 NOX allowance allocations to opt-in units. (a) NO X...

  11. 40 CFR 97.10 - Authorization and responsibilities of NOX authorized account representative.

    Science.gov (United States)

    2010-07-01

    ... NOX authorized account representative. 97.10 Section 97.10 Protection of Environment ENVIRONMENTAL... SO2 TRADING PROGRAMS NOX Authorized Account Representative for NOX Budget Sources § 97.10 Authorization and responsibilities of NOX authorized account representative. (a) Except as provided under § 97...

  12. 40 CFR 97.86 - Withdrawal from NOX Budget Trading Program.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Withdrawal from NOX Budget Trading... PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS Individual Unit Opt-ins. § 97.86 Withdrawal from NOX Budget Trading Program. (a) Requesting withdrawal. To...

  13. 40 CFR 97.186 - Withdrawal from CAIR NOX Annual Trading Program.

    Science.gov (United States)

    2010-07-01

    ... Trading Program. 97.186 Section 97.186 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS CAIR NOX Opt-In Units § 97.186 Withdrawal from CAIR NOX Annual Trading Program. Except as provided...

  14. 40 CFR 97.386 - Withdrawal from CAIR NOX Ozone Season Trading Program.

    Science.gov (United States)

    2010-07-01

    ... Trading Program. 97.386 Section 97.386 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS CAIR NOX Ozone Season Opt-in Units § 97.386 Withdrawal from CAIR NOX Ozone Season Trading Program...

  15. 40 CFR 96.86 - Withdrawal from NOX Budget Trading Program.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Withdrawal from NOX Budget Trading... PROGRAMS (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS FOR STATE IMPLEMENTATION PLANS Individual Unit Opt-ins § 96.86 Withdrawal from NOX Budget Trading Program. (a) Requesting...

  16. 40 CFR 96.186 - Withdrawal from CAIR NOX Annual Trading Program.

    Science.gov (United States)

    2010-07-01

    ... Trading Program. 96.186 Section 96.186 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS FOR STATE IMPLEMENTATION PLANS CAIR NOX Opt-in Units § 96.186 Withdrawal from CAIR NOX Annual Trading...

  17. Estimating the NOx produced by lightning from GOME and NLDN data: a case study in the Gulf of Mexico

    Directory of Open Access Journals (Sweden)

    S. Beirle

    2006-01-01

    Full Text Available Nitrogen oxides (NOxNO+NO2 play an important role in tropospheric chemistry, in particular in catalytic ozone production. Lightning provides a natural source of nitrogen oxides, dominating the production in the tropical upper troposphere, with strong impact on tropospheric ozone and the atmosphere's oxidizing capacity. Recent estimates of lightning produced NOx (LNOx are of the order of 5 Tg [N] per year with still high uncertainties in the range of one order of magnitude. The Global Ozone Monitoring Experiment (GOME on board the ESA-satellite ERS-2 allows the retrieval of tropospheric column densities of NO2 on a global scale. Here we present the GOME NO2 measurement directly over a large convective system over the Gulf of Mexico. Simultaneously, cloud-to-ground (CG flashes are counted by the U.S. National Lightning Detection Network (NLDNTM, and extrapolated to include intra-cloud (IC+CG flashes based on a climatological IC:CG ratio derived from NASA's space-based lightning sensors. A series of 14 GOME pixels shows largely enhanced column densities over thick and high clouds, coinciding with strong lightning activity. The enhancements can not be explained by transport of anthropogenic NOx and must be due to fresh production of LNOx. A quantitative analysis, accounting in particular for the visibility of LNOx from satellite, yields a LNOx production of 90 (32-240 moles of NOx, or 1.3 (0.4-3.4 kg [N], per flash. If simply extrapolated, this corresponds to a global LNOx production of 1.7 (0.6-4.7Tg [N]/yr.

  18. NOx Control for Utility Boiler OTR Compliance

    Energy Technology Data Exchange (ETDEWEB)

    Hamid Farzan; Jennifer L. Sivy

    2005-07-30

    Babcock & Wilcox Power Generation Group (B&W) and Fuel Tech, Inc. (Fuel Tech) teamed to evaluate an integrated solution for NO{sub x} control comprised of B&W's DRB-4Z{reg_sign} low-NO{sub x} pulverized coal (PC) burner technology and Fuel Tech's NO{sub x}OUT{reg_sign}, a selective non-catalytic reduction (SNCR) technology, capable of meeting a target emission limit of 0.15 lb NO{sub x}/10{sup 6} Btu. In a previous project sponsored by the U.S. Department of Energy (DOE), promising results were obtained with this technology from large-scale testing in B&W's 100-million Btu/hr Clean Environment Development Facility (CEDF) which simulates the conditions of large coal-fired utility boilers. Under the most challenging boiler temperatures at full load conditions, NO{sub x} emissions of 0.19 lb/10{sup 6} Btu were achieved firing Powder River Basin coal while controlling ammonia slip to less than 5 ppm. At a 40 million Btu/hr firing rate, NO{sub x} emissions were as low as 0.09 lb/10{sup 6} Btu. Improved performance with this system was proposed for this new program with injection at full load via a convective pass multiple nozzle lance (MNL) in front of the superheater tubes or in the convective tube bank. Convective pass lances represent the current state-of-the-art in SNCR and needed to be evaluated in order to assess the full potential of the combined technologies. The objective of the program was to achieve a NO{sub x} level below 0.15 lb/10{sup 6} Btu (with ammonia slip of less than 5 ppm) in the CEDF using PRB coal and B&W's DRB-4Z{reg_sign} low-NO{sub x} pulverized coal (PC) burner in combination with dual zone overfire air ports and Fuel Tech's NO{sub x}OUT{reg_sign} System. Commercial installations of B&W's low-NO{sub x} burner, in combination with overfire air ports using PRB coal, have demonstrated a NO{sub x} level of 0.15 to 0.2 lb/10{sup 6} Btu under staged combustion conditions. The proposed goal of the combustion system (no

  19. CATALYTIC PROPERTIES AND ACIDITY OF MODIFIED MCM-41 ...

    African Journals Online (AJOL)

    a

    obtain H-form catalysts, samples were heated to remove the NH3 gas. Catalytic tests ... connected to a Perkin-Elmer gas phase chromatograph equipped with a flame ionisation detector and Perkin-Elmer ..... exchanged with noble metals present some disadvantages such as high cost of platinum or palladium, rapid ...

  20. Reduction of Fe(III)EDTA by Klebsiella sp. strain FD-3 in NOx scrubber solutions.

    Science.gov (United States)

    Zhou, Zuoming; Jing, Guohua; Zheng, Xiangjiao

    2013-03-01

    Biological reduction of Fe(III) to Fe(II) is a key step in nitrogen oxides (NOx) removal by the integrated chemical absorption-biological reduction method, which determines the concentration of Fe(II) in the scrubbing liquid. A new Fe(III)EDTA reduction strain, named as FD-3, was isolated from mixed cultures used in the integrated NOx removal process and identified as Klebsiella sp. by 16S rDNA sequence analysis. The reduction abilities of FD-3 and the influence of nitrogen-containing compounds (Fe(II)EDTA-NO, NO3(-) and NO2(-)) and sulfur-containing compounds (SO4(2-), SO3(2-)) on the Fe(III)EDTA reduction were investigated. The results indicated that strain FD-3 could reduce Fe(III)EDTA efficiently. NO3(-), NO2(-) and Fe(II)EDTA-NO inhibit the reduction of Fe(III)EDTA and could also serve as electron acceptor for strain FD-3. SO3(2-) inhibited Fe(III)EDTA reduction while SO4(2-) had no obviously effect on Fe(III)EDTA reduction. The relationship between cell growth and Fe(III)EDTA reduction could be described by the models based on Logistic equation. Copyright © 2013 Elsevier Ltd. All rights reserved.

  1. Measurement of NOx fluxes from a tall tower in Beijing

    Science.gov (United States)

    Squires, Freya; Dunmore, Rachel; Lewis, Alastair; Vaughan, Adam; Mullinger, Neil; Nemitz, Eiko; Wild, Oliver; Zhang, Qiang; Hamilton, Jacqueline; Lee, James; Fu, Pingqing

    2017-04-01

    Nitrogen Oxides (NOx, the sum of nitrogen monoxide (NO) and nitrogen dioxide (NO2)) are significant anthropogenic pollutants emitted from most combustion processes. NOx is a precursor species to the formation of O3 and secondary aerosols and, in high concentrations, NO2 can have adverse effects on human health through action as a respiratory irritant. For these reasons, there has been increased focus on improving NOx emissions inventories, typically developed using 'bottom-up' estimates of emissions from their sources, which are used to predict current and future air quality and to guide abatement strategy. Recent studies have shown a discrepancy between NOx inventories and measured NOx emissions for UK cities, highlighting the limitations of bottom-up emissions inventories and the importance of accurate measurement data to improve the estimates. Similarly, inventories in China are associated with large uncertainties and are rapidly changing with time in response to economic development and new environmental regulation. Here, we present data collected as part of the Air Pollutants in Beijing (AIRPOLL-Beijing) campaign from an urban site located at the Institute of Atmospheric Physics, Chinese Academy of Sciences (IAP, CAS) (39˚ 58'28"N, 116˚ 22'16"E) in central Beijing. NOx concentrations were measured using a state-of-the-art chemiluminescence instrument, sampling from an inlet at 100 metres on a meteorological tower. Measurements at 5 Hz coupled with wind vector data measured by a sonic anemometer located at the same height as the inlet allowed NOx emission fluxes to be calculated using the eddy covariance method. Measurements were made during the period 11/11/2016 - 10/12/2016 and compared to existing emission estimates from The Multi-resolution Emission Inventory for China (MEIC) inventory. It is anticipated that this work will be used to evaluate the accuracy of emissions inventories for Beijing, to develop improved emissions estimates and thus provide

  2. Electrochemical catalytic treatment of phenol wastewater

    International Nuclear Information System (INIS)

    Ma Hongzhu; Zhang Xinhai; Ma Qingliang; Wang Bo

    2009-01-01

    The slurry bed catalytic treatment of contaminated water appears to be a promising alternative for the oxidation of aqueous organic pollutants. In this paper, the electrochemical oxidation of phenol in synthetic wastewater catalyzed by ferric sulfate and potassium permanganate adsorbed onto active bentonite in slurry bed electrolytic reactor with graphite electrode has been investigated. In order to determine the optimum operating condition, the orthogonal experiments were devised and the results revealed that the system of ferric sulfate, potassium permanganate and active bentonite showed a high catalytic efficiency on the process of electrochemical oxidation phenol in initial pH 5. When the initial concentration of phenol was 0.52 g/L (the initial COD 1214 mg/L), up to 99% chemical oxygen demand (COD) removal was obtained in 40 min. According to the experimental results, a possible mechanism of catalytic degradation of phenol was proposed. Environmental estimation was also done and the results showed that the treated wastewater have little impact on plant growth and could totally be applied to irrigation.

  3. Federal NOx Budget Trading Program and CAIR NOx and SO2 Trading Programs (40 CFR Part 97)

    Science.gov (United States)

    This part establishes general provisions and the applicability, permitting, allowance, excess emissions, monitoring, and opt-in provisions for the federal NOx Budget Trading Program as a means of mitigating interstate transport of ozone and nitrogen oxides

  4. Catalytic reforming methods

    Science.gov (United States)

    Tadd, Andrew R; Schwank, Johannes

    2013-05-14

    A catalytic reforming method is disclosed herein. The method includes sequentially supplying a plurality of feedstocks of variable compositions to a reformer. The method further includes adding a respective predetermined co-reactant to each of the plurality of feedstocks to obtain a substantially constant output from the reformer for the plurality of feedstocks. The respective predetermined co-reactant is based on a C/H/O atomic composition for a respective one of the plurality of feedstocks and a predetermined C/H/O atomic composition for the substantially constant output.

  5. Alternative deNOx catalysts and technologies

    DEFF Research Database (Denmark)

    Due-Hansen, Johannes

    . The commercial catalyst used for the selective catalytic reduction (SCR) of nitrogen oxides exhibits high activity and selectivity towards N2. However, the vanadia-titania-based catalyst used is very sensitive to deactivation by alkali-species (primarily potassium), which are typically present in high amounts...... a catalyst less susceptible to the poisons present in the flue gas, a number of catalysts have been synthesized and tested in the present work, all based on commercially available supports. A highly acidic support consisting of sulfated zirconia was chosen based on preliminary studies. A number of different...... active species distributed on the support were investigated, such as iron, copper and vanadium oxides. However, based on the catalysts performance in the SCR reaction and their resistances towards potassium, the most promising candidate of the formulations studied was the vanadia-loaded catalyst, i.e. V2...

  6. Gaseous ligand selectivity of the H-NOX sensor protein from Shewanella oneidensis and comparison to those of other bacterial H-NOXs and soluble guanylyl cyclase.

    Science.gov (United States)

    Wu, Gang; Liu, Wen; Berka, Vladimir; Tsai, Ah-Lim

    2017-09-01

    To delineate the commonalities and differences in gaseous ligand discrimination among the heme-based sensors with Heme Nitric oxide/OXygen binding protein (H-NOX) scaffold, the binding kinetic parameters for gaseous ligands NO, CO, and O 2 , including K D , k on , and k off , of Shewanella oneidensis H-NOX (So H-NOX) were characterized in detail in this study and compared to those of previously characterized H-NOXs from Clostridium botulinum (Cb H-NOX), Nostoc sp. (Ns H-NOX), Thermoanaerobacter tengcongensis (Tt H-NOX), Vibrio cholera (Vc H-NOX), and human soluble guanylyl cyclase (sGC), an H-NOX analogue. The K D (NO) and K D (CO) of each bacterial H-NOX or sGC follow the "sliding scale rule"; the affinities of the bacterial H-NOXs for NO and CO vary in a small range but stronger than those of sGC by at least two orders of magnitude. On the other hand, each bacterial H-NOX exhibits different characters in the stability of its 6c NO complex, reactivity with secondary NO, stability of oxyferrous heme and autoxidation to ferric heme. A facile access channel for gaseous ligands is also identified, implying that ligand access has only minimal effect on gaseous ligand selectivity of H-NOXs or sGC. This comparative study of the binding parameters of the bacterial H-NOXs and sGC provides a basis to guide future new structural and functional studies of each specific heme sensor with the H-NOX protein fold. Copyright © 2017 Elsevier B.V. and Société Française de Biochimie et Biologie Moléculaire (SFBBM). All rights reserved.

  7. Optimization of an electrochemical cell with an adsorption layer for NOx removal

    DEFF Research Database (Denmark)

    Shao, Jing; Kammer Hansen, Kent

    2012-01-01

    The structure of a multilayer electrochemical cell with an adsorption layer was optimized by removing an yttriastabilized zirconia cover layer. It was found that the NOx removal properties of the electrochemical cell were dramatically enhanced through the optimization, especially under conditions...

  8. Catalytic Antibodies: Concept and Promise

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 12; Issue 11. Catalytic Antibodies: Concept and Promise. Desirazu N Rao Bharath Wootla. General Article Volume 12 Issue ... Keywords. Catalytic antibodies; abzymes; hybridome technology; Diels– Alder reaction; Michaelis– Menten kinetics; Factor VIII.

  9. Catalytic interface erosion

    International Nuclear Information System (INIS)

    Meng, H.; Cohen, E.G.D.

    1995-01-01

    We study interface erosion processes: catalytic erosions. We present two cases. (1) The erosion of a completely occupied lattice by one single moving particle starting from somewhere inside the lattice, considering deterministic as well as probabilistic erosion rules. In the latter case, the eroded regions appear to have interfaces with continuously tunable fractal dimensions. (2) The kinetic roughening of an initially flat surface, where ballistic or diffusion-limited particles, which remain intact themselves, erode the surface coming from the outside, using the same erosion rules as in (1). Many features resembling realistic interfaces, for example, islands and inlets, are generated. The dependence of the surface width on the system size is due to both the erosion mechanism and the way particles move before reaching the surface

  10. Catalytic detritiation of water

    International Nuclear Information System (INIS)

    Rogers, M.L.; Lamberger, P.H.; Ellis, R.E.; Mills, T.K.

    1977-01-01

    A pilot-scale system has been used at Mound Laboratory to investigate the catalytic detritiation of water. A hydrophobic, precious metal catalyst is used to promote the exchange of tritium between liquid water and gaseous hydrogen at 60 0 C. Two columns are used, each 7.5 m long by 2.5 cm ID and packed with catalyst. Water flow is 5-10 cm 3 /min and countercurrent hydrogen flow is 9,000-12,000 cm 3 /min. The equipment, except for the columns, is housed in an inert atmosphere glovebox and is computer controlled. The hydrogen is obtained by electrolysis of a portion of the water stream. Enriched gaseous tritium is withdrawn for further enrichment. A description of the system is included along with an outline of its operation. Recent experimental data are discussed

  11. Using hydroponic biomass to regulate NOx emissions in long range space travel

    Energy Technology Data Exchange (ETDEWEB)

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

    2002-02-01

    The incineration of wastes is one of the most promising reclamation technologies being developed for life support in long range space travel. However, incineration in a closed environment will build up hazardous NOx if not regulated. A technology that can remove NOx under microgravity conditions without the need of expendables is required. Activated carbon prepared from inedible wheat straw and sweet potato stalk that were grown under hydroponic conditions has been demonstrated to be able to adsorb NO and reduce it to N{sub 2}. The high mineral content in the activated carbon prepared from hydroponic biomass prohibits high surface area production and results in inferior NO adsorption capacity. The removal of mineral from the carbon circumvents the aforementioned negative effect. The optimal production conditions to obtain maximum yield and surface area for the activated carbon have been determined. A parametric study on the NO removal efficiency by the activated carbon has been done. The presence of oxygen in flue gas is essential for effective adsorption of NO by the activated carbon. On the contrary, water vapor inhibits the adsorption efficiency of NO. The NO adsorption capacity and the duration before it exceeds the Space Maximum Allowable Concentration were determined. After the adsorption of NO, the activated carbon can be regenerated for reuse by heating the carbon bed under anaerobic conditions to above 500 C, when the adsorbed NO is reduced to N{sub 2}. The regenerated activated carbon exhibits improved NO adsorption efficiency. However, regeneration had burned off a small percentage of the activated carbon.

  12. Reduction of NOx and PM in marine diesel engine exhaust gas using microwave plasma

    Science.gov (United States)

    Balachandran, W.; FInst, P.; Manivannan, N.; Beleca, R.; Abbod, M.

    2015-10-01

    Abatement of NOx and particulate matters (PM) of marine diesel exhaust gas using microwave (MW) non-thermal plasma is presented in this paper. NOx mainly consist of NO and less concentration of NO2 in a typical two stoke marine diesel engine and microwave plasma generation can completely remove NO. MW was generated using two 2kW microwave sources and a saw tooth passive electrode. Passive electrode was used to generate high electric field region within microwave environment where high energetic electrons (1-3eV) are produced for the generation of non-thermal plasma (NTP). 2kW gen-set diesel exhaust gas was used to test our pilot-scale MW plasma reactor. The experimental results show that almost 100% removal of NO is possible for the exhaust gas flow rate of 60l/s. It was also shown that MW can significantly remove soot particles (PM, 10nm to 365nm) entrained in the exhaust gas of 200kW marine diesel engine with 40% engine load and gas flow rate of 130l/s. MW without generating plasma showed reduction up to 50% reduction of PM and with the plasma up to 90% reduction. The major challenge in these experiments was that igniting the desired plasma and sustaining it with passive electrodes for longer period (10s of minutes) as it required fine tuning of electrode position, which was influenced by many factors such as gas flow rate, geometry of reactor and MW power.

  13. Control strategies for vehicular NOx emissions in Guangzhou, China

    International Nuclear Information System (INIS)

    Shao Min; Zhang Yuanhang; Raufer, Roger

    2001-01-01

    Guangzhou is a city in southern China that has experienced very rapid economic development in recent years. The city's air has very high concentrations of various pollutants, including sulphur dioxide (SO 2 , oxides of nitrogen (NOx), ozone (O 3 ) and particulate. This paper reviews the changes in air quality in the city over the past 15 years, and notes that a serious vehicular-related emissions problem has been superimposed on the traditional coal-burning problem evident in most Chinese cities. As NOx concentrations have increased, oxidants and photochemical smog now interact with the traditional SO 2 and particulate pollutants, leading to increased health risks and other environmental concerns. Any responsible NOx control strategy for the city must include vehicle emission control measures. This paper reviews control strategies designed to abate vehicle emissions to fulfill the city's air quality improvement target in 2010. A cost-effectiveness analysis suggests that, while NOx emission control is expensive, vehicular emission standards could achieve a relatively sizable emissions reduction at reasonable cost. To achieve the 2010 air quality target of NOx, advanced implementation of EURO3 standards is recommended, substituting for the EURO2 currently envisioned in the national regulations Related technical options, including fuel quality improvements and inspection/maintenance (I/M) upgrades (ASM or IM240) are assessed as well. (author)

  14. NOx Effects on Photochemical Aging of Urban Wet Particles

    Science.gov (United States)

    Lim, Y. B.; Seo, J.; Kim, J. Y.; Turpin, B. J.

    2017-12-01

    Aqueous chemistry in aerosol liquid water (ALW) has been considered an important pathway of particle formation, which is expected to improve current models; however, little is known about NOx effects on aqueous chemistry in wet urban particulate matter (PM). Here we show photochemical aging of wet aerosols at modest urban conditions conducted in a smog chamber and provide atmospheric evidence of these chamber reactions. At high relative humidity, HNO3, the main sink of photochemistry of NOx, initiates water uptake into aerosols and ALW in turn facilitates aqueous chemistry. The hygroscopic growth was significant, and aqueous chemistry led to mainly non-radical products, such as organonitrates and oligomers. This multiphase chemistry contributes to particle aging during a haze event in Seoul, a megacity in East Asia. PM2.5 at Seoul, a downwind site at high NOx conditions, and reference PM2.5 at Deokjeok Island, an upwind site that has no emission source, during winter including the haze period were analyzed. Chemical components of Seoul haze particles can be explained by photochemical aging of transported particles in the presence of NOx. East Asian megacities including Seoul suffer from high concentration particles, yet the formation is poorly understood. Our finding of chemical aging and secondary formation highlights the importance of multiphase reactions, including gas-phase photochemistry at high NOx and aqueous chemistry in ALW, which need to be incorporated into air quality models to improve predictions for public health.

  15. Nuclear Nox4-Derived Reactive Oxygen Species in Myelodysplastic Syndromes

    Directory of Open Access Journals (Sweden)

    Marianna Guida

    2014-01-01

    Full Text Available A role for intracellular ROS production has been recently implicated in the pathogenesis and progression of a wide variety of neoplasias. ROS sources, such as NAD(PH oxidase (Nox complexes, are frequently activated in AML (acute myeloid leukemia blasts and strongly contribute to their proliferation, survival, and drug resistance. Myelodysplastic syndromes (MDS comprise a heterogeneous group of disorders characterized by ineffective hematopoiesis, with an increased propensity to develop AML. The molecular basis for MDS progression is unknown, but a key element in MDS disease progression is the genomic instability. NADPH oxidases are now recognized to have specific subcellular localizations, this targeting to specific compartments for localized ROS production. Local Nox-dependent ROS production in the nucleus may contribute to the regulation of redox-dependent cell growth, differentiation, senescence, DNA damage, and apoptosis. We observed that Nox1, 2, and 4 isoforms and p22phox and Rac1 subunits are expressed in MDS/AML cell lines and MDS samples, also in the nuclear fractions. Interestingly, Nox4 interacts with ERK and Akt1 within nuclear speckle domain, suggesting that Nox4 could be involved in regulating gene expression and splicing factor activity. These data contribute to the elucidation of the molecular mechanisms used by nuclear ROS to drive MDS evolution to AML.

  16. Catalytic Combustion of Gasified Waste

    Energy Technology Data Exchange (ETDEWEB)

    Kusar, Henrik

    2003-09-01

    This thesis concerns catalytic combustion for gas turbine application using a low heating-value (LHV) gas, derived from gasified waste. The main research in catalytic combustion focuses on methane as fuel, but an increasing interest is directed towards catalytic combustion of LHV fuels. This thesis shows that it is possible to catalytically combust a LHV gas and to oxidize fuel-bound nitrogen (NH{sub 3}) directly into N{sub 2} without forming NO{sub x} The first part of the thesis gives a background to the system. It defines waste, shortly describes gasification and more thoroughly catalytic combustion. The second part of the present thesis, paper I, concerns the development and testing of potential catalysts for catalytic combustion of LHV gases. The objective of this work was to investigate the possibility to use a stable metal oxide instead of noble metals as ignition catalyst and at the same time reduce the formation of NO{sub x} In paper II pilot-scale tests were carried out to prove the potential of catalytic combustion using real gasified waste and to compare with the results obtained in laboratory scale using a synthetic gas simulating gasified waste. In paper III, selective catalytic oxidation for decreasing the NO{sub x} formation from fuel-bound nitrogen was examined using two different approaches: fuel-lean and fuel-rich conditions. Finally, the last part of the thesis deals with deactivation of catalysts. The various deactivation processes which may affect high-temperature catalytic combustion are reviewed in paper IV. In paper V the poisoning effect of low amounts of sulfur was studied; various metal oxides as well as supported palladium and platinum catalysts were used as catalysts for combustion of a synthetic gas. In conclusion, with the results obtained in this thesis it would be possible to compose a working catalytic system for gas turbine application using a LHV gas.

  17. Photo-catalytic Removal of Methyl Orange Dye by Polyaniline ...

    African Journals Online (AJOL)

    http://dx.doi.org/10.4314/star.v3i2.13 · AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's Partners · Terms and Conditions of Use · Contact AJOL · News. OTHER RESOURCES... for Researchers · for Journals · for Authors · for Policy Makers ...

  18. Impacts of the abolition of NOx emission trade; Effecten van de afschaffing van NOx- emissiehandel

    Energy Technology Data Exchange (ETDEWEB)

    Kroon, P. [ECN Beleidsstudies, Petten (Netherlands)

    2012-09-15

    The consequences of abolishing the NOx emission trade have been analyzed for the installations that are covered by BEMS legislation (Dutch decree on emission limits for medium-sized combustion plants). The following aspects have been analyzed: What are the enforcement costs if these installations need to comply with BEMS requirements as of 2014?; How are these costs distributed across the various sectors and in particular for the sectors of onshore/offshore gas and oil extraction, greenhouse horticulture and hospitals?; To what extent can costs be lowered by allowing a 2-,3- or 5-year delay of the implementation date for existing installations in BEMS? To answer the above questions, data were used from the NEA (Netherlands Emission Authority) at sector level. Model calculations were conducted to determine the costs and effects [Dutch] De gevolgen van de afschaffing van NOx-emissiehandel zijn geanalyseerd voor het installatiepark dat terugvalt op BEMS-wetgeving (Besluit emissie-eisen middelgrote stookinstallaties). De volgende zaken zijn geanalyseerd: Wat zijn de nalevingskosten indien vanaf 2014 deze installaties aan de BEMS-eisen moeten voldoen?; Hoe zijn deze kosten verdeeld over de verschillende sectoren en in het bijzonder voor de sectoren offshore/onshore gas- en oliewinning, de glastuinbouw en ziekenhuizen?; In hoeverre zijn de kosten te verlagen door 2, 3 of 5 jaar uitstel te geven ten opzichte van de implementatiedatum voor bestaande installaties in BEMS? Voor het beantwoorden van de bovenstaande vragen is gebruik gemaakt van gegevens van de NEa (Nederlandse Emissie autoriteit) op sectorniveau. Met modelberekeningen zijn hiermee kosten en effecten bepaald.

  19. Selective catalytic reduction system and process using a pre-sulfated zirconia binder

    Science.gov (United States)

    Sobolevskiy, Anatoly; Rossin, Joseph A.

    2010-06-29

    A selective catalytic reduction (SCR) process with a palladium catalyst for reducing NOx in a gas, using hydrogen as a reducing agent is provided. The process comprises contacting the gas stream with a catalyst system, the catalyst system comprising (ZrO.sub.2)SO.sub.4, palladium, and a pre-sulfated zirconia binder. The inclusion of a pre-sulfated zirconia binder substantially increases the durability of a Pd-based SCR catalyst system. A system for implementing the disclosed process is further provided.

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

    Science.gov (United States)

    Chen, Yuche; Borken-Kleefeld, Jens

    2016-04-05

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

  1. Anomalous HNO3/NOx ratio of remote tropospheric air: Conversion of nitric acid to formic acid and NOx?

    Science.gov (United States)

    Chatfield, Robert B.

    1994-12-01

    The N oxidation ratio, [HNO3]/ [NOx], in the free troposphere is measured at ˜ 1 to 9 (averaging ˜5), consistently lower than the values of 15-100 which known theory suggests to be reached rapidly. This discrepancy casts doubt on current models' abilities to predict effects of NO sources on remote [NO], and so also [O3] and [OH]. HNO3-to-NOx recycling processes involving HCHO in solution are appealing explanations for the ratio. Known chemical theory are illustrated using a Lagrangian box model of the mid-troposphere which simulates characteristic episodes from NOx input to HNO3 washout. Ratio and budget constraint equations for NOy, can usefully restrict conceivable explanations of missing chemistry of fast nitrogen cycling; most explanations could be called “fast-cycles” or “re-NOx-ification.” These equations also show how current global models may suggest spuriously good N oxidation ratios and errors in OH. Aerosol or cloud droplets reactions with HCHO may produce (a) formic acid (which needs an appropriate source) and NOx, or alternatively, (b) hydroxymethyl nitrate (or methyl dinitrate), which might supply a large, variable amount of “missing NOy” not currently measurable except by NOy instruments.

  2. Comparison and evaluation of anthropogenic emissions of SO2 and NOx over China

    Science.gov (United States)

    Li, Meng; Klimont, Zbigniew; Zhang, Qiang; Martin, Randall V.; Zheng, Bo; Heyes, Chris; Cofala, Janusz; Zhang, Yuxuan; He, Kebin

    2018-03-01

    Bottom-up emission inventories provide primary understanding of sources of air pollution and essential input of chemical transport models. Focusing on SO2 and NOx, we conducted a comprehensive evaluation of two widely used anthropogenic emission inventories over China, ECLIPSE and MIX, to explore the potential sources of uncertainties and find clues to improve emission inventories. We first compared the activity rates and emission factors used in two inventories and investigated the reasons of differences and the impacts on emission estimates. We found that SO2 emission estimates are consistent between two inventories (with 1 % differences), while NOx emissions in ECLIPSE's estimates are 16 % lower than those of MIX. The FGD (flue-gas desulfurization) device penetration rate and removal efficiency, LNB (low-NOx burner) application rate and abatement efficiency in power plants, emission factors of industrial boilers and various vehicle types, and vehicle fleet need further verification. Diesel consumptions are quite uncertain in current inventories. Discrepancies at the sectorial and provincial levels are much higher than those of the national total. We then examined the impacts of different inventories on model performance by using the nested GEOS-Chem model. We finally derived top-down emissions by using the retrieved columns from the Ozone Monitoring Instrument (OMI) compared with the bottom-up estimates. High correlations were observed for SO2 between model results and OMI columns. For NOx, negative biases in bottom-up gridded emission inventories (-21 % for MIX, -39 % for ECLIPSE) were found compared to the satellite-based emissions. The emission trends from 2005 to 2010 estimated by two inventories were both consistent with satellite observations. The inventories appear to be fit for evaluation of the policies at an aggregated or national level; more work is needed in specific areas in order to improve the accuracy and robustness of outcomes at finer spatial

  3. Comparison and evaluation of anthropogenic emissions of SO2 and NOx over China

    Directory of Open Access Journals (Sweden)

    M. Li

    2018-03-01

    Full Text Available Bottom-up emission inventories provide primary understanding of sources of air pollution and essential input of chemical transport models. Focusing on SO2 and NOx, we conducted a comprehensive evaluation of two widely used anthropogenic emission inventories over China, ECLIPSE and MIX, to explore the potential sources of uncertainties and find clues to improve emission inventories. We first compared the activity rates and emission factors used in two inventories and investigated the reasons of differences and the impacts on emission estimates. We found that SO2 emission estimates are consistent between two inventories (with 1 % differences, while NOx emissions in ECLIPSE's estimates are 16 % lower than those of MIX. The FGD (flue-gas desulfurization device penetration rate and removal efficiency, LNB (low-NOx burner application rate and abatement efficiency in power plants, emission factors of industrial boilers and various vehicle types, and vehicle fleet need further verification. Diesel consumptions are quite uncertain in current inventories. Discrepancies at the sectorial and provincial levels are much higher than those of the national total. We then examined the impacts of different inventories on model performance by using the nested GEOS-Chem model. We finally derived top-down emissions by using the retrieved columns from the Ozone Monitoring Instrument (OMI compared with the bottom-up estimates. High correlations were observed for SO2 between model results and OMI columns. For NOx, negative biases in bottom-up gridded emission inventories (−21 % for MIX, −39 % for ECLIPSE were found compared to the satellite-based emissions. The emission trends from 2005 to 2010 estimated by two inventories were both consistent with satellite observations. The inventories appear to be fit for evaluation of the policies at an aggregated or national level; more work is needed in specific areas in order to improve the accuracy and robustness of

  4. NOx reduction by compact electron beam processing

    International Nuclear Information System (INIS)

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

    1995-01-01

    Among the new methods being investigated for the post-combustion removal of nitrogen oxides (NO x ) are based on non-thermal plasmas. These plasmas can be produced by electrical discharge methods or electron beam irradiation. The application of electron beam irradiation for NO x removal in power plant flue gases has been investigated since the early 1970's in both laboratory- and pilot-scale experiments. Electrical discharge methods are relatively new entrants in the field of flue gas cleanup. Pulsed corona and dielectric-barrier discharge techniques are two of the more commonly used electrical discharge methods for producing nonthermal plasmas at atmospheric pressure. There are basically two types of reactions responsible for the depletion of NO by non-thermal plasmas: oxidation and reduction

  5. NOx cycle and tropospheric ozone isotope anomaly: an experimental investigation

    Science.gov (United States)

    Michalski, G.; Bhattacharya, S. K.; Girsch, G.

    2013-04-01

    The oxygen isotope composition of nitrogen oxides (NOx) in the atmosphere may be a useful tool for understanding the oxidation of NOx into nitric acid/nitrate in the atmosphere. A set of experiments were conducted to examine changes in isotopic composition of NOx due to O3-NOx photochemical cycling. At low NO2/O2 mixing ratios, NO2 becomes progressively and nearly equally enriched in 17O and 18O over time until it reaches a steady state with Δ17O values of 40.6 ± 1.9‰ and δ18O values of 84.2 ± 4‰, relative to the isotopic composition of the O2 gas. As the mixing ratio increases, isotopic exchange between O atoms and O2 and NOx suppresses the isotopic enrichments. A kinetic model simulating the observed data shows that the isotope effects during ozone formation play a more dominant role compared to kinetic isotope effects during NO oxidation or exchange of NO2. The model results are consistent with the data when the NO + O3 reaction occurs mainly via the transfer of the terminal atom of O3. The model predicts that under tropospheric concentrations of the three reactants, the timescale of NOx isotopic equilibrium ranges from hours (ppbv mixing ratios) to days/weeks (pptv) and yields steady state Δ17O and δ18O values of 46‰ and 115‰ respectively with respect to Vienna Standard Mean Ocean Water. Interpretation of tropospheric nitrate isotope data can now be done with the derived rate coefficients of the major isotopologue reactions at various pressures.

  6. Catalytic production of biodiesel

    Energy Technology Data Exchange (ETDEWEB)

    Theilgaard Madsen, A.

    2011-07-01

    The focus of this thesis is the catalytic production of diesel from biomass, especially emphasising catalytic conversion of waste vegetable oils and fats. In chapter 1 an introduction to biofuels and a review on different catalytic methods for diesel production from biomass is given. Two of these methods have been used industrially for a number of years already, namely the transesterification (and esterification) of oils and fats with methanol to form fatty acid methyl esters (FAME), and the hydrodeoxygenation (HDO) of fats and oils to form straight-chain alkanes. Other possible routes to diesel include upgrading and deoxygenation of pyrolysis oils or aqueous sludge wastes, condensations and reductions of sugars in aqueous phase (aqueous-phase reforming, APR) for monofunctional hydrocarbons, and gasification of any type of biomass followed by Fischer-Tropsch-synthesis for alkane biofuels. These methods have not yet been industrialised, but may be more promising due to the larger abundance of their potential feedstocks, especially waste feedstocks. Chapter 2 deals with formation of FAME from waste fats and oils. A range of acidic catalysts were tested in a model fat mixture of methanol, lauric acid and trioctanoin. Sulphonic acid-functionalised ionic liquids showed extremely fast convertion of lauric acid to methyl laurate, and trioctanoate was converted to methyl octanoate within 24 h. A catalyst based on a sulphonated carbon-matrix made by pyrolysing (or carbonising) carbohydrates, so-called sulphonated pyrolysed sucrose (SPS), was optimised further. No systematic dependency on pyrolysis and sulphonation conditions could be obtained, however, with respect to esterification activity, but high activity was obtained in the model fat mixture. SPS impregnated on opel-cell Al{sub 2}O{sub 3} and microporous SiO{sub 2} (ISPS) was much less active in the esterification than the original SPS powder due to low loading and thereby low number of strongly acidic sites on the

  7. Pilot test and optimization of plasma based deNOx

    DEFF Research Database (Denmark)

    Stamate, Eugen; Chen, Weifeng; Michelsen, Poul

    The NOx reduction of flue gas by plasma generated ozone was investigated in pilot test experiments at two industrial power plants running on natural gas (Ringsted) and biomass (Haslev). Reduction rates higher than 95% have been achieved for a molar ratio O3:NOx of 1.56. Fourier transform infrared...... and ultraviolet absorption spectroscopy were used for spatial measurements of stable molecules and radicals along the reduction reactor. Reactions of O3 injected in the flue gas in the reduction reactor were also modeled including the influence of the flue gas temperature, water droplets and SOx and HCl content...

  8. Analysis and Measurement of NOx Emissions in Port Auxiliary Vessels

    Directory of Open Access Journals (Sweden)

    German de Melo Rodriguez

    2013-09-01

    Full Text Available This paper is made NOx pollution emitted by port auxiliary vessels, specifically by harbour tugs, due to its unique operating characteristics of operation, require a large propulsion power changes discontinuously, also possess some peculiar technical characteristics, large tonnage and high propulsive power, that differentiate them from other auxiliary vessels of the port. Taking into account all the above features, there are no studies of the NOx emission engines caused by different working regimes of power because engine manufacturers have not measured these emissions across the range of operating power, but usually we only report the pollution produced by its engines to a maximum continuous power.

  9. Catalytic cracking with deasphalted oil

    Energy Technology Data Exchange (ETDEWEB)

    Beaton, W.I.; Taylor, J.L.; Peck, L.B.; Mosby, J.F.

    1990-07-10

    This patent describes a catalytic cracking process. It comprises: hydrotreating resid; thereafter deasphalting the hydrotreated resid to produce substantially deasphalted oil; catalytically cracking the hydrotreated oil in a catalytic cracking unit in the presence of a cracking catalyst to produce upgraded oil leaving coked catalyst; and regenerating the coked catalyst in the presence of a combustion-supporting gas comprising excess molecular oxygen in an amount greater than the stoichiometric amount required for substantially completely combusting the coke on the catalyst to carbon dioxide.

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

    Science.gov (United States)

    Matsumoto, J.

    2013-12-01

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

  11. NOx Solutions for Biodiesel: Final Report; Report 6 in a Series of 6

    Energy Technology Data Exchange (ETDEWEB)

    McCormick, R. L.; Alvarez, J. R.; Graboski, M. S.

    2003-02-01

    A number of studies have shown substantial particulate matter (PM) reductions for biodiesel, but also a significant increase in nitrogen oxides (NOx) emissions. This study examines a number of approaches for NOx reduction from biodiesel.

  12. NOx emission trade. What is the state-of-the-art?

    International Nuclear Information System (INIS)

    Witkamp, J.

    2003-01-01

    In Leiden, Netherlands, 28 November 2002, a symposium was organized on the subject of NOx emission trade in preparation of a NOx emission trade system. In this article an overview is given of the developments so far [nl

  13. Catalytic Membrane Sensors

    Energy Technology Data Exchange (ETDEWEB)

    Boyle, T.J.; Brinker, C.J.; Gardner, T.J.; Hughes, R.C.; Sault, A.G.

    1998-12-01

    The proposed "catalytic membrane sensor" (CMS) was developed to generate a device which would selectively identify a specific reagent in a complex mixture of gases. This was to be accomplished by modifying an existing Hz sensor with a series of thin films. Through selectively sieving the desired component from a complex mixture and identifying it by decomposing it into Hz (and other by-products), a Hz sensor could then be used to detect the presence of the select component. The proposed "sandwich-type" modifications involved the deposition of a catalyst layered between two size selective sol-gel layers on a Pd/Ni resistive Hz sensor. The role of the catalyst was to convert organic materials to Hz and organic by-products. The role of the membraneo was to impart both chemical specificity by molecukir sieving of the analyte and converted product streams, as well as controlling access to the underlying Pd/Ni sensor. Ultimately, an array of these CMS elements encompassing different catalysts and membranes were to be developed which would enable improved selectivity and specificity from a compiex mixture of organic gases via pattern recognition methodologies. We have successfully generated a CMS device by a series of spin-coat deposited methods; however, it was determined that the high temperature required to activate the catalyst, destroys the sensor.

  14. Catalytic cracking of lignites

    Energy Technology Data Exchange (ETDEWEB)

    Seitz, M.; Nowak, S.; Naegler, T.; Zimmermann, J. [Hochschule Merseburg (Germany); Welscher, J.; Schwieger, W. [Erlangen-Nuernberg Univ. (Germany); Hahn, T. [Halle-Wittenberg Univ., Halle (Germany)

    2013-11-01

    A most important factor for the chemical industry is the availability of cheap raw materials. As the oil price of crude oil is rising alternative feedstocks like coal are coming into focus. This work, the catalytic cracking of lignite is part of the alliance ibi (innovative Braunkohlenintegration) to use lignite as a raw material to produce chemicals. With this new one step process without an input of external hydrogen, mostly propylene, butenes and aromatics and char are formed. The product yield depends on manifold process parameters. The use of acid catalysts (zeolites like MFI) shows the highest amount of the desired products. Hydrogen rich lignites with a molar H/C ratio of > 1 are to be favoured. Due to primary cracking and secondary reactions the ratio between catalyst and lignite, temperature and residence time are the most important parameter to control the product distribution. Experiments at 500 C in a discontinuous rotary kiln reactor show yields up to 32 wt-% of hydrocarbons per lignite (maf - moisture and ash free) and 43 wt-% char, which can be gasified. Particularly, the yields of propylene and butenes as main products can be enhanced four times to about 8 wt-% by the use of catalysts while the tar yield decreases. In order to develop this innovative process catalyst systems fixed on beads were developed for an easy separation and regeneration of the used catalyst from the formed char. (orig.)

  15. Aircraft NO(x) had no Unique Fingerprint on Sonex; Lightning Dominated Fresh NO(x) Sources

    Science.gov (United States)

    Thompson, A.; Sparling, L.; Kondo, Y.; Anderson, B.; Gregory, G.; Sachse, G.

    1999-01-01

    Key questions to which SONEX was directed were the following: Can aircraft corridors be detected? Is there a unique tracer for aircraft NO(x)? Can a "background" NO(x) (or NO(y) be defined? What fraction of NO(x) measured during SONEX was from aircraft? How representative was SONEX of the North Atlantic in 1997 and how typical of other years? We attempt to answer these questions through species-species correlations, probability distribution functions (PDFs), and meteorological history. There is not a unique aircraft tracer, largely due to the high variability of air mass origins and tracer ratios, which render "average" quantities meaningless. The greatest NO and NO(y) signals were associated with lightning and convective NO sources. Well-defined background CO, NO(y) and NO(y)/ozone ratio appear in subsets of two cross-track flights with subtropical origins and five flights with predominantly mid-latitude air. Forty percent of the observations on these 7 flights showed NO(y)/ozone to be above background, evidently due to unreacted NO(x). This NO(x) is a combination of aircraft, lightning and surface pollution injected by convection. The strongly subtropical signatures in SONEX observations, confirmed by pv (potential vorticity) values along flight tracks, argues for most of the unreacted NO(x) originating from lightning. Potential vorticity statistics along SONEX flight tracks in 1992-1998, and for the North Atlantic as a whole, show the SONEX meteorological environment to be representative of the North Atlantic flight corridor in the October-November period.

  16. Alkali resistant Cu/zeolite deNOx catalysts for flue gas cleaning in biomass fired applications

    DEFF Research Database (Denmark)

    Putluru, Siva Sankar Reddy; Riisager, Anders; Fehrmann, Rasmus

    2011-01-01

    Cu/zeolite catalysts have been prepared by wet impregnation and characterized by N2 physisorption, EPR, H2-TPR and NH3-TPD methods. The Cu content was varied to optimize the loading as well as surface acidity. Optimized Cu/zeolite catalysts showed high surface acidity and excellent activity...... in the selective catalytic reduction (SCR) of NO with NH3. Furthermore, Cu/zeolite catalysts showed high SCR activity even after doping with potassium (0–500μmol/g) compared to a commercial vanadium catalyst which deactivated at lower potassium content. Fresh and deactivated catalysts were further examined...... to investigate the redox and acidic properties of the catalysts. The poisoning resistivity seems to be due to a combination of high surface area and strong acidity of the Cu/zeolite catalysts. The catalysts might be attractive alternatives to conventional catalysts for deNOx of flue gases from biomass fired...

  17. Biodiesel unsaturation degree effects on diesel engine NOx emissions and cotton wick flame temperature

    OpenAIRE

    Abdullah Mohd Fareez Edzuan; Zhing Sim Shu; Bilong Bugik Clarence

    2017-01-01

    As compared with conventional diesel fuel, biodiesel has better lubricity and lower particulate matter (PM) emissions however nitrogen oxides (NOx) emissions generally increase in biodiesel-fuelled diesel engine. Strict regulation on NOx emissions is being implemented in current Euro 6 standard and it is expected to be tighter in next standard, thus increase of NOx cannot be accepted. In this study, biodiesel unsaturation degree effects on NOx emissions are investigated. Canola, palm and coco...

  18. Method for reducing NOx during combustion of coal in a burner

    Science.gov (United States)

    Zhou, Bing [Cranbury, NJ; Parasher, Sukesh [Lawrenceville, NJ; Hare, Jeffrey J [Provo, UT; Harding, N Stanley [North Salt Lake, UT; Black, Stephanie E [Sandy, UT; Johnson, Kenneth R [Highland, UT

    2008-04-15

    An organically complexed nanocatalyst composition is applied to or mixed with coal prior to or upon introducing the coal into a coal burner in order to catalyze the removal of coal nitrogen from the coal and its conversion into nitrogen gas prior to combustion of the coal. This process leads to reduced NOx production during coal combustion. The nanocatalyst compositions include a nanoparticle catalyst that is made using a dispersing agent that can bond with the catalyst atoms. The dispersing agent forms stable, dispersed, nano-sized catalyst particles. The catalyst composition can be formed as a stable suspension to facilitate storage, transportation and application of the catalyst nanoparticles to a coal material. The catalyst composition can be applied before or after pulverizing the coal material or it may be injected directly into the coal burner together with pulverized coal.

  19. Catalytic conversion of ethanol on H-Y zeolite

    Directory of Open Access Journals (Sweden)

    Čegar Nedeljko

    2005-01-01

    Full Text Available The catalytic activity of the H-form of synthetic zeolite NaY was examined in this study. The catalytic activity was determined according to the rate of ethanol conversion in a gas phase in the static system. In the conversion of ethanol on synthetic NaY zeolite at 585, 595, and 610 K, on which the reaction develops at an optimal rate, ethene and diethyl ether are evolved in approximately the same quantity. After transforming the NaY zeolite into the H-form, its catalytic activity was extremely increases so, the reaction develops at a significantly lower temperature with a very large increase in the reaction rate. The distribution of the products also changes, so that at lower temperatures diethyl ether is elvolved in most cases, and the development of ethene is favored at higher ones, and after a certain period of time there is almost complete conversion of ethanol into ethene. The increase in catalytic activity, as well as the change of selectivity of conversion of ethanol on the H-form of zeolite, is the result of removing Na+ cations in the NaY zeolite, so that more acidic catalyst is obtained which contains a number of acidic catalytically active centers, as well as a more powerful one compared to the original NaY zeolite.

  20. OXYGEN ENHANCED COMBUSTION FOR NOx CONTROL

    Energy Technology Data Exchange (ETDEWEB)

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

    2000-07-01

    Increased environmental regulations will require utility boilers to reduce NO{sub x} emissions to less than 0.15lb/MMBtu in the near term. Conventional technologies such as Selective Catalytic Reduction (SCR) and Selective Non-Catalytic Reduction (SNCR) are unable to achieve these lowered emission levels without substantially higher costs and major operating problems. Oxygen enhanced combustion is a novel technology that allows utilities to meet the NO{sub x} emission requirements without the operational problems that occur with SCR and SNCR. Furthermore, oxygen enhanced combustion can achieve these NO{sub x} limits at costs lower than conventional technologies. The objective of this program is to demonstrate the use of oxygen enhanced combustion as a technical and economical method of meeting the EPA State Implementation Plan for NO{sub x} reduction to less than 0.15lb/MMBtu for a wide range of boilers and coal. The oxygen enhanced coal combustion program (Task 1) focused this quarter on the specific objective of exploration of the impact of oxygen enrichment on NO{sub x} formation utilizing small-scale combustors for parametric testing. Research efforts toward understanding any limitations to the applicability of the technology to different burners and fuels such as different types of coal are underway. The objective of the oxygen transport membrane (OTM) materials development program (Task 2.1) is to ascertain a suitable material composition that can be fabricated into dense tubes capable of producing the target oxygen flux under the operating conditions. This requires that the material have sufficient oxygen permeation resulting from high oxygen ion conductivity, high electronic conductivity and high oxygen surface exchange rate. The OTM element development program (Task 2.2) objective is to develop, fabricate and characterize OTM elements for laboratory and pilot reactors utilizing quality control parameters to ensure reproducibility and superior performance

  1. NOx Emission in Iron and Steel Production: A Review of Control Measures for Safe and Eco-Friendly Environment

    Directory of Open Access Journals (Sweden)

    U. A. Mukhtar

    2017-12-01

    Full Text Available Iron and steel manufacturing involved preparation of raw materials through processes such as sintering, pelletizing and coke making. During these processes, pollutants such as Sulphur (iv oxides (SO2 Carbon II oxides (CO, Nitrogen oxides (NOX, Volatile organic compounds (VOC and Particulate matter (PM etc. are emitted. The present work is aimed at describing some mitigation technologies of controlling emissions in iron and steel production. The processes involved in the production of iron and steel using Blast Furnace (BF and Basic Oxygen Furnace (BOF has been described. The mitigation technologies of controlling emissions were analyzed and discussed with environmental impacts based on the economical and technical factors. In this work, the data presented is based on existing reviews. The combination of low NOX burner (LNB and Selective catalytic reduction (SCR is capable of reducing emission for up to 90% and above. Emissions of other pollutants into the atmosphere as a result of ammonia slip, formation of acids and other gases are harmful to the environment and causes damage to the SCR systems. Installation and operation cost are the major impacts of the SCR technology in the process of iron and steel production.

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

    Science.gov (United States)

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

    2016-06-24

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

  3. Catalytic pyrolysis of lignocellulosic biomass

    NARCIS (Netherlands)

    Seshan, Kulathuiyer; Sa, Jacinto

    2014-01-01

    This chapter reports on the latest developments of biomass catalytic pyrolysis for the production of fuels. The primary focus is on the role of catalysts in the process, namely, their influence in the liquefaction of lignocellulosic biomass.

  4. 40 CFR 52.326 - Area-wide nitrogen oxides (NOX) exemptions.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 3 2010-07-01 2010-07-01 false Area-wide nitrogen oxides (NOX... PROGRAMS (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS Colorado § 52.326 Area-wide nitrogen oxides (NOX) exemptions. The Denver Regional Council of Governments (DRCOG) submitted a NOX exemption...

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

    Science.gov (United States)

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

  6. 40 CFR 1043.50 - Approval of methods to meet Tier 1 retrofit NOX standards.

    Science.gov (United States)

    2010-07-01

    ... retrofit NOX standards. 1043.50 Section 1043.50 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS CONTROL OF NOX, SOX, AND PM EMISSIONS FROM MARINE ENGINES AND VESSELS SUBJECT TO THE MARPOL PROTOCOL § 1043.50 Approval of methods to meet Tier 1 retrofit NOX standards...

  7. 40 CFR 52.2351 - Area-wide nitrogen oxides (NOX) exemption.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 4 2010-07-01 2010-07-01 false Area-wide nitrogen oxides (NOX... nitrogen oxides (NOX) exemption. On May 2, 1997, Ursula Trueman, Director, Division of Air Quality, Utah...)(2)(A) of the Clean Air Act as amended in 1990, a section 182(f)(2) NOX Reasonably Available Control...

  8. 40 CFR 60.4380 - How are excess emissions and monitor downtime defined for NOX?

    Science.gov (United States)

    2010-07-01

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

  9. 78 FR 68367 - Approval and Promulgation of Air Quality Implementation Plans; Ohio; Ohio NOX

    Science.gov (United States)

    2013-11-14

    ...] Approval and Promulgation of Air Quality Implementation Plans; Ohio; Ohio NOX SIP Call Rule Revisions... that supersedes the NOx Budget Trading Program. States subject to both the NO X SIP Call and CAIR's... ``The NOx allowance tracking system.'', effective October 18, 2010. (C) October 8, 2010, ``Director's...

  10. 75 FR 37433 - Notice of Data Availability Concerning 2010 CAIR NOX

    Science.gov (United States)

    2010-06-29

    ... ENVIRONMENTAL PROTECTION AGENCY [FRL-9169-5] Notice of Data Availability Concerning 2010 CAIR NOX...-mail: CAIR_NOx[email protected] . B. Mail: Robert L. Miller, U.S. Environmental Protection... EPA's Web site at http://www.epa.gov/airmarkets/cair/nox_annual_nusa/index.html . EPA will publish a...

  11. Re-vision as Remediation : Hypermediacy and Translation in Anne Carson’s Nox

    NARCIS (Netherlands)

    Brillenburg Wurth, C.A.W.

    2013-01-01

    This article explores Anne Carson’s Nox (2010) in the light of remediation. Nox is a book about death and the recording of loss: lost time, a lost brother, and lost presence. It conveys this loss through the logic of hypermediacy and a word-for-word translation of Catullus 101. Nox reworks the

  12. 40 CFR 96.386 - Withdrawal from CAIR NOX Ozone Season Trading Program.

    Science.gov (United States)

    2010-07-01

    ... Trading Program. 96.386 Section 96.386 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS FOR... Season Trading Program. Except as provided under paragraph (g) of this section, a CAIR NOX Ozone Season...

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

    Science.gov (United States)

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

    2003-01-01

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

  14. 40 CFR 86.327-79 - Quench checks; NOX analyzer.

    Science.gov (United States)

    2010-07-01

    ... any flow rate into the reaction chamber. This includes, but is not limited to, sample capillary, ozone... Quench checks; NOX analyzer. (a) Perform the reaction chamber quench check for each model of high vacuum reaction chamber analyzer prior to initial use. (b) Perform the reaction chamber quench check for each new...

  15. 40 CFR 76.12 - Phase I NOX compliance extension.

    Science.gov (United States)

    2010-07-01

    ....12 Section 76.12 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS... reliability problems are due substantially to NOX emission control system installation and availability; or... outage. (iii) Fuel and energy balance summaries and power and other consumption requirements (including...

  16. Een optimale instrumentenmix voor industriële NOx emissies

    NARCIS (Netherlands)

    Uylenburg, R.; Peeters, M.; Oosterhuis, F.; Boeve, M.N.; Faure, M.; Philipsen, N.

    2012-01-01

    ACELS voerde samen met het instituut Metro van de Universiteit Maastricht en het Instituut voor Milieuvraagstukken een onderzoek uit in opdracht van het ministerie van I en M, waarbij gezocht werd naar een optimale instrumentenmix voor industriële NOx emissies. Die regulering vindt thans plaats door

  17. NOx SOx Secondary NAAQS: Integrated Review Plan - CASAC Advisory

    Science.gov (United States)

    The NOx SOx Secondary NAAQS Integrated Review Plan is the first document generated as part of the National Ambient Air Quality Standards (NAAQS) review process. The Plan presents background information, the schedule for the review, the process to be used in conducting the review,...

  18. 78 FR 57153 - Proposed Information Collection Request; Comment Request; NOX

    Science.gov (United States)

    2013-09-17

    ... ENVIRONMENTAL PROTECTION AGENCY [EPA-HQ-OAR-2006-0947; FRL--9901-08-OAR] Proposed Information Collection Request; Comment Request; NOX Budget Trading Program To Reduce the Regional Transport of Ozone (Renewal) AGENCY: Environmental Protection Agency (EPA). ACTION: Notice. SUMMARY: The Environmental...

  19. Low NOx combustion using cogenerated oxygen and nitrogen streams

    Science.gov (United States)

    Kobayashi, Hisashi [Putnam Valley, NY; Bool, Lawrence E [East Aurora, NY; Snyder, William J [Ossining, NY

    2009-02-03

    Combustion of hydrocarbon fuel is achieved with less formation of NOx by feeding the fuel into a slightly oxygen-enriched atmosphere, and separating air into oxygen-rich and nitrogen-rich streams which are fed separately into the combustion device.

  20. Synergie Klimaat- en NOx-beleid: Een kostenevaluatie tot 2010

    NARCIS (Netherlands)

    Smeets WLM; Hoen A; Wijngaart RA van den; LED

    2005-01-01

    Bij de aankoop van relatief goedkope CO2-emissierechten in het buitenland worden binnenlandse synergetische neveneffecten op de emissies van luchtverontreinigende stoffen gemist en zullen extra kosten moeten worden gemaakt voor het realiseren van de nationale emissieplafonds van NOx, SO2, en

  1. Biomass fuel characterization for NOx emissions in cofiring applications

    NARCIS (Netherlands)

    Di Nola, G.

    2007-01-01

    This dissertation investigates the impact of various biomass fuels and combustion conditions on the NOx emissions during biomass co-firing. Fossil fuels dominated the energy scenario since the industrial revolution. However, in the last decades, increasing concerns about their availability and

  2. Pressure Effects on the Thermal De-NOx Process

    DEFF Research Database (Denmark)

    Kjærgaard, Karsten; Glarborg, Peter; Dam-Johansen, Kim

    1996-01-01

    The effect of pressure on the thermal de-NOx process has been investigated in flow reactor experiments. The experiments were performed at pressures from 1 to 10 bar and temperatures ranging from 925 to 1375 K. The inlet O-2 level was varied from 1000 ppm to 10%, while NH3 and NO were maintained a...

  3. Updated analysis of Denmark's possibilities of reducing NO{sub X} emissions; En opdateret analyse af Danmarks muligheder for at reducere emissionerne af NOx

    Energy Technology Data Exchange (ETDEWEB)

    COWI A/S, Kgs. Lyngby (Denmark)

    2009-07-01

    The update of the measures included in the 2006 analysis has given the following key results: 1) A number of measures such as boosting and reburning on power stations and other large point sources are no longer considered as relevant measures. 2) Minor revisions and adjustments have been implemented for measures in the industry, district heating sector, for mobile sources and for offshore. 3) Additional measures have been considered. This includes primarily the use of SNCR (Selective Non-Catalytic Reduction) and SCR (Selective Catalytic Reduction). Most sources of NO{sub x} emissions can be fitted with either of these abatement technologies. There is for example a potential by more frequent replacement of the catalytic elements in the SCR units. Also by increased ammonia dosing the reduction in SNCR units can be increased. These are relevant measures in waste incineration installations. The report includes rough estimates of reduction potentials and costs. The calculations show the costs and benefits of the relevant measures. The measures are ranked according to their shadow price with the damage costs of emissions of one kg NO{sub x}, being DKK 52 per kg NO{sub x}. The measures with a shadow price of less than the damage costs would give a welfare-economic surplus. This implies that the most cost-effective measures are 1) Better controls for gas engines at combined heat and power plants (CHP) 2) Optimisation of SNCR in waste incineration installations 3) Replacement to low-NO{sub x} burners at light oil fuel kettles in industry and CHP The measures in CHP and industry remove 3300 tonnes NO{sub x} in 2010. The measures imply a cost of DKK 3 million per year for the business sector and DKK 12 million per year for the government due to a loss in tax revenues. Moreover reductions can be expected from the measures within the waste incineration installations, but the exact potential has not been estimated here. A number of sensitivity analyses have been carried out

  4. Weight loss is associated with improved endothelial dysfunction via NOX2-generated oxidative stress down-regulation in patients with the metabolic syndrome.

    Science.gov (United States)

    Angelico, Francesco; Loffredo, Lorenzo; Pignatelli, Pasquale; Augelletti, Teresa; Carnevale, Roberto; Pacella, Antonio; Albanese, Fabiana; Mancini, Ilaria; Di Santo, Serena; Del Ben, Maria; Violi, Francesco

    2012-06-01

    The aim of this study was to assess whether adherence to a restricted-calorie, Mediterranean-type diet improves endothelial dysfunction and markers of oxidative stress in patients with metabolic syndrome. A moderately low-calorie (600 calories/day negative energy balance), low-fat, high-carbohydrate diet (fat, fat and 55% from carbohydrate) was prescribed to 53 outpatients with the metabolic syndrome. Participants were divided into two groups according to body weight loss > or weight (-6.8%), body-mass-index (-4.6%), waist circumference (-4.8%), HOMA-IR (-27.2%), plasma glucose, glycosylated haemoglobin, total and LDL-cholesterol, blood pressure, serum NOX2 (the catalytic core of NADPH oxidase) (-22.2%) and urinary8-isoprostanes (-39.0%) and an increase of serum NOx (Nitrite/Nitrate) (+116.8%) and adiponectine (+125.5%) as compared with those in group B (n = 30). A statistically significant increase in brachial artery flow-mediated dilatation was observed in group A (+24.7%; p weight loss is able to improve endothelial dysfunction in patients with the metabolic syndrome. The coexistent decrease of NOX2 activation suggests a role for oxidative stress in eliciting artery dysfunction.

  5. DeNOx Abatement over Sonically Prepared Iron-Substituted Y, USY and MFI Zeolite Catalysts in Lean Exhaust Gas Conditions

    Science.gov (United States)

    Stachurska, Patrycja; Kuterasiński, Łukasz; Dziedzicka, Anna; Górecka, Sylwia; Chmielarz, Lucjan; Łojewska, Joanna; Sitarz, Maciej

    2018-01-01

    Iron-substituted MFI, Y and USY zeolites prepared by two preparation routes—classical ion exchange and the ultrasound modified ion-exchange method—were characterised by micro-Raman spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and ultraviolet (UV)/visible diffuse reflectance spectroscopy (UV/Vis DRS). Ultrasound irradiation, a new technique for the preparation of the metal salt suspension before incorporation to the zeolite structure, was employed. An experimental study of selective catalytic reduction (SCR) of NO with NH3 on both iron-substituted reference zeolite catalysts and those prepared through the application of ultrasound conducted during an ion-exchange process is presented. The prepared zeolite catalysts show high activity and selectivity in SCR deNOx abatement. The MFI-based iron catalysts, especially those prepared via the sonochemical method, revealed superior activity in the deNOx process, with almost 100% selectivity towards N2. The hydrothermal stability test confirmed high stability and activity of MFI-based catalysts in water-rich conditions during the deNOx reaction at 450 °C. PMID:29301370

  6. Atmospheric emission of NOx from mining explosives: A critical review

    Science.gov (United States)

    Oluwoye, Ibukun; Dlugogorski, Bogdan Z.; Gore, Jeff; Oskierski, Hans C.; Altarawneh, Mohammednoor

    2017-10-01

    High-energy materials such as emulsions, slurries and ammonium-nitrate fuel-oil (ANFO) explosives play crucial roles in mining, quarrying, tunnelling and many other infrastructure activities, because of their excellent transport and blasting properties. These explosives engender environmental concerns, due to atmospheric pollution caused by emission of dust and nitrogen oxides (NOx) from blasts, the latter characterised by the average emission factor of 5 kg (t AN explosive)-1. This first-of-its-kind review provides a concise literature account of the formation of NOx during blasting of AN-based explosives, employed in surface operations. We estimate the total NOx emission rate from AN-based explosives as 0.05 Tg (i.e., 5 × 104 t) N per annum, compared to the total global annual anthropogenic NOx emissions of 41.3 × 106 t N y-1. Although minor in the global sense, the large localised plumes from blasting exhibit high NOx concentration (500 ppm) exceeding up to 3000 times the international standards. This emission has profound consequences at mining sites and for adjacent atmospheric environment, necessitating expensive management of exclusion zones. The review describes different types of AN energetic materials for civilian applications, and summarises the essential properties and terminologies pertaining to their use. Furthermore, we recapitulate the mechanisms that lead to the formation of the reactive nitrogen species in blasting of AN-based explosives, review their implications to atmospheric air pollution, and compare the mechanisms with those experienced in other thermal and combustion operations. We also examine the mitigation approaches, including guidelines and operational-control measures. The review discusses the abatement technologies such as the formulation of new explosive mixtures, comprising secondary fuels, spin traps and other additives, in light of their effectiveness and efficiency. We conclude the review with a summary of unresolved problems

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

    Science.gov (United States)

    Dynamic evaluation seeks to assess the ability of photochemical models to replicate changes in air quality as emissions and other conditions change. When a model fails to replicate an observed change, a key challenge is to discern whether the discrepancy is caused by errors in meteorological simulations, errors in emission magnitudes and changes, or inaccurate responses of simulated pollutant concentrations to emission changes. In this study, the Community Multiscale Air Quality (CMAQ) model is applied to simulate the ozone (O3) change after the NOx SIP Call and mobile emission controls substantially reduced nitrogen oxides (NOx) emissions in the eastern U.S. from 2002 to 2006. For both modeled and observed O3, changes in episode average daily maximal 8-h O3 were highly correlated (R2 = 0.89) with changes in the 95th percentile, although the magnitudes of reductions increased nonlinearly at high percentile O3 concentrations. Observed downward changes in mean NOx (−11.6 to −2.5 ppb) and 8-h O3 (−10.4 to −4.7 ppb) concentrations in metropolitan areas in the NOx SIP Call region were under-predicted by 31%–64% and 26%–66%, respectively. The under-predicted O3 improvements in the NOx SIP Call region could not be explained by adjusting for temperature biases in the meteorological input, or by considering uncertainties in the chemical reaction rate constants. However, the under-prediction in O3 improvements could be alleviated by 5%–31% by constraining NO

  8. Selective catalytic reduction system and process for control of NO.sub.x emissions in a sulfur-containing gas stream

    Science.gov (United States)

    Sobolevskiy, Anatoly

    2015-08-11

    An exhaust gas treatment process, apparatus, and system for reducing the concentration of NOx, CO and hydrocarbons in a gas stream, such as an exhaust stream (29), via selective catalytic reduction with ammonia is provided. The process, apparatus and system include a catalytic bed (32) having a reducing only catalyst portion (34) and a downstream reducing-plus-oxidizing portion (36). Each portion (34, 36) includes an amount of tungsten. The reducing-plus-oxidizing catalyst portion (36) advantageously includes a greater amount of tungsten than the reducing catalyst portion (36) to markedly limit ammonia salt formation.

  9. Catalytic Ozonation of Phenolic Wastewater: Identification and Toxicity of Intermediates

    Directory of Open Access Journals (Sweden)

    Mahdi Farzadkia

    2014-01-01

    Full Text Available A new strategy in catalytic ozonation removal method for degradation and detoxification of phenol from industrial wastewater was investigated. Magnetic carbon nanocomposite, as a novel catalyst, was synthesized and then used in the catalytic ozonation process (COP and the effects of operational conditions such as initial pH, reaction time, and initial concentration of phenol on the degradation efficiency and the toxicity assay have been investigated. The results showed that the highest catalytic potential was achieved at optimal neutral pH and the removal efficiency of phenol and COD is 98.5% and 69.8%, respectively. First-order modeling demonstrated that the reactions were dependent on the initial concentration of phenol, with kinetic constants varying from 0.038 min−1  ([phenol]o = 1500 mg/L to 1.273 min−1 ([phenol]o = 50 mg/L. Bioassay analysis showed that phenol was highly toxic to Daphnia magna (LC50 96 h=5.6 mg/L. Comparison of toxicity units (TU of row wastewater (36.01 and the treated effluent showed that TU value, after slightly increasing in the first steps of ozonation for construction of more toxic intermediates, severely reduced at the end of reaction (2.23. Thus, COP was able to effectively remove the toxicity of intermediates which were formed during the chemical oxidation of phenolic wastewaters.

  10. The selectivity of Vibrio cholerae H-NOX for gaseous ligands follows the "sliding scale rule" hypothesis. Ligand interactions with both ferrous and ferric Vc H-NOX.

    Science.gov (United States)

    Wu, Gang; Liu, Wen; Berka, Vladimir; Tsai, Ah-lim

    2013-12-31

    Vc H-NOX (or VCA0720) is an H-NOX (heme-nitric oxide and oxygen binding) protein from facultative aerobic bacterium Vibrio cholerae. It shares significant sequence homology with soluble guanylyl cyclase (sGC), a NO sensor protein commonly found in animals. Similar to sGC, Vc H-NOX binds strongly to NO and CO with affinities of 0.27 nM and 0.77 μM, respectively, but weakly to O2. When positioned on a "sliding scale" plot [Tsai, A.-l., et al. (2012) Biochemistry 51, 172-186], the line connecting log K(D)(NO) and log K(D)(CO) of Vc H-NOX can almost be superimposed with that of Ns H-NOX. Therefore, the measured affinities and kinetic parameters of gaseous ligands to Vc H-NOX provide more evidence to validate the "sliding scale rule" hypothesis. Like sGC, Vc H-NOX binds NO in multiple steps, forming first a six-coordinate heme-NO complex at a rate of 1.1 × 10(9) M(-1) s(-1), and then converts to a five-coordinate heme-NO complex at a rate that is also dependent on NO concentration. Although the formation of oxyferrous Vc H-NOX cannot be detected at a normal atmospheric oxygen level, ferrous Vc H-NOX is oxidized to the ferric form at a rate of 0.06 s(-1) when mixed with O2. Ferric Vc H-NOX exists as a mixture of high- and low-spin states and is influenced by binding to different ligands. Characterization of both ferric and ferrous Vc H-NOX and their complexes with various ligands lays the foundation for understanding the possible dual roles in gas and redox sensing of Vc H-NOX.

  11. Correlation of NOX1 and NOX2 expression in ulcerative colitis tissue with intestinal mucosal oxidative stress response and barrier function injury

    Directory of Open Access Journals (Sweden)

    Tao Ma

    2017-10-01

    Full Text Available Objective: To study the correlation of NOX1 and NOX2 expression in ulcerative colitis tissue with intestinal mucosal oxidative stress response and barrier function injury. Methods: A total of 69 patients who were diagnosed with ulcerative colitis in Yan’an People’s Hospital between May 2015 and March 2017 were selected as the UC group of the research, and 78 patients who were diagnosed with colon polyps were selected as the polyps group of the research. The ulcerative colitis lesion and polyp lesion were collected to detect the expression of NOX1 and NOX2, the generation of oxygen free radicals as well as the contents of apoptosis molecules and mucosal barrier molecules. Results: The mRNA expression and protein expression of NOX1 and NOX2 in the intestinal mucosa of UC group were significantly higher than those of polyps group; LPO, MDA, AOPP, NO, PDCD5 and Bax levels in intestinal mucosa of UC group were significantly higher than those of polyps group and positively correlated with the mRNA expression and protein expression of NOX1 and NOX2 while Bcl-2, Cdx1, Cdx2, galectin-1, galectin-3, OCLN, cingulin and ZO-1 levels were significantly lower than those of polyps group and negatively correlated with the mRNA expression and protein expression of NOX1 and NOX2. Conclusion: The high expression of NOX1 and NOX2 in ulcerative colitis tissue can activate the intestinal mucosal oxidative stress response and result in the intestinal mucosal barrier function injury.

  12. Model predictive control of a lean-burn gasoline engine coupled with a passive selective catalytic reduction system

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Pingen [Tennessee Technological University (TTU); Lin, Qinghua [Tennessee Technological University (TTU); Prikhodko, Vitaly Y. [ORNL

    2017-10-01

    Lean-burn gasoline engines have demonstrated 10–20% engine efficiency gain over stoichiometric engines and are widely considered as a promising technology for meeting the 54.5 miles-per-gallon (mpg) Corporate Average Fuel Economy standard by 2025. Nevertheless, NOx emissions control for lean-burn gasoline for meeting the stringent EPA Tier 3 emission standards has been one of the main challenges towards the commercialization of highly-efficient lean-burn gasoline engines in the United States. Passive selective catalytic reduction (SCR) systems, which consist of a three-way catalyst and SCR, have demonstrated great potentials of effectively reducing NOx emissions for lean gasoline engines but may cause significant fuel penalty due to ammonia generation via rich engine combustion. The purpose of this study is to develop a model-predictive control (MPC) scheme for a lean-burn gasoline engine coupled with a passive SCR system to minimize the fuel penalty associated with passive SCR operation while satisfying stringent NOx and NH3 emissions requirements. Simulation results demonstrate that the MPC-based control can reduce the fuel penalty by 47.7% in a simulated US06 cycle and 32.0% in a simulated UDDS cycle, compared to the baseline control, while achieving over 96% deNOx efficiency and less than 15 ppm tailpipe ammonia slip. The proposed MPC control can potentially enable high engine efficiency gain for highly-efficient lean-burn gasoline engine while meeting the stringent EPA Tier 3 emission standards.

  13. Thermal Reduction of NOx with Recycled Plastics.

    Science.gov (United States)

    Oluwoye, Ibukun; Dlugogorski, Bogdan Z; Gore, Jeff; Vyazovkin, Sergey; Boyron, Olivier; Altarawneh, Mohammednoor

    2017-07-05

    This study develops technology for mitigation of NO x formed in thermal processes using recycled plastics such as polyethylene (PE). Experiments involve sample characterization, and thermogravimetric decomposition of PE under controlled atmospheres, with NO x concentration relevant to industrial applications. TGA-Fourier transform infrared (FTIR) spectroscopy and NO x chemiluminescence serve to obtain the removal efficiency of NO x by fragments of pyrolyzing PE. Typical NO x removal efficiency amounts to 80%. We apply the isoconversional method to derive the kinetic parameters, and observe an increasing dependency of activation energy on the reaction progress. The activation energies of the process span 135 kJ/mol to 226 kJ/mol, and 188 kJ/mol to 268 kJ/mol, for neat and recycled PE, respectively, and the so-called compensation effect accounts for the natural logarithmic pre-exponential ln (A/min -1 ) factors of ca. 19-35 and 28-41, in the same order, depending on the PE conversion in the experimental interval of between 5 and 95%. The observed delay in thermal events of recycled PE reflects different types of PE in the plastic, as measurements of intrinsic viscosity indicate that, the recycled PE comprises longer linear chains. The present evaluation of isoconversional activation energies affords accurate kinetic modeling of both isothermal and nonisothermal decomposition of PE in NO x -doped atmosphere. Subsequent investigations will focus on the effect of mass transfer and the presence of oxygen, as reburning of NO x in large-scale combustors take place at higher temperatures than those included in the current study.

  14. Tattoo removal.

    Science.gov (United States)

    Adatto, Maurice A; Halachmi, Shlomit; Lapidoth, Moshe

    2011-01-01

    Over 50,000 new tattoos are placed each year in the United States. Studies estimate that 24% of American college students have tattoos and 10% of male American adults have a tattoo. The rising popularity of tattoos has spurred a corresponding increase in tattoo removal. Not all tattoos are placed intentionally or for aesthetic reasons though. Traumatic tattoos due to unintentional penetration of exogenous pigments can also occur, as well as the placement of medical tattoos to mark treatment boundaries, for example in radiation therapy. Protocols for tattoo removal have evolved over history. The first evidence of tattoo removal attempts was found in Egyptian mummies, dated to have lived 4,000 years BC. Ancient Greek writings describe tattoo removal with salt abrasion or with a paste containing cloves of white garlic mixed with Alexandrian cantharidin. With the advent of Q-switched lasers in the late 1960s, the outcomes of tattoo removal changed radically. In addition to their selective absorption by the pigment, the extremely short pulse duration of Q-switched lasers has made them the gold standard for tattoo removal. Copyright © 2011 S. Karger AG, Basel.

  15. Paraben degradation using catalytic ozonation over volcanic rocks.

    Science.gov (United States)

    Gomes, João F; Quinta-Ferreira, Maria Emília; Costa, Raquel; Quinta-Ferreira, Rosa M; Martins, Rui C

    2018-03-01

    Parabens are widely used as antimicrobial and preservatives in pharmaceutical and personal care products and are continuously reaching the water streams. Conventional wastewater treatments are proven inefficient on the removal of this kind of contaminants from wastewater. Therefore, catalytic ozonation appears as a suitable option, due to the oxidant power of ozone and its high capacity of hydroxyl radical generation in the presence of a suitable catalyst. The main drawback of catalytic ozonation is related with the choice of stable and active catalysts at low cost. On this way, two volcanic rocks were tested to enhance the removal of a mixture of parabens by ozonation, improving their degradation. Indeed, catalytic ozonation with volcanic rock allowed total paraben degradation using a transferred ozone dose (TOD) of 55 mg/L which corresponds to a reduction of about threefold the amount of TOD comparatively with single ozonation (170 mg/L of TOD). Due to the presence of semiconductors on volcanic rock composition, the effect of UVA irradiation on paraben degradation was analyzed. The neutral and basic conditions enhanced catalytic ozonation comparatively to acid conditions. Higher pH values allowed a total methylparaben degradation with 35 mg O 3 /L, whereas for low pH values, 55 mg O 3 /L was required. The use of a radical scavenger proven that hydroxyl radicals are the main responsible for paraben degradation with catalytic ozonation. This was confirmed through the analysis of the by-products, where 4-hydroxybenzoic acid, 3,4-dihydroxybenzoic acid (3,4-diHBA), 2,4-dihydroxybenzoic acid, and hydroquinone were quantified.

  16. Gaseous Heterogeneous Catalytic Reactions over Mn-Based Oxides for Environmental Applications: A Critical Review.

    Science.gov (United States)

    Xu, Haomiao; Yan, Naiqiang; Qu, Zan; Liu, Wei; Mei, Jian; Huang, Wenjun; Zhao, Songjian

    2017-08-15

    Manganese oxide has been recognized as one of the most promising gaseous heterogeneous catalysts due to its low cost, environmental friendliness, and high catalytic oxidation performance. Mn-based oxides can be classified into four types: (1) single manganese oxide (MnOx), (2) supported manganese oxide (MnOx/support), (3) composite manganese oxides (MnOx-X), and (4) special crystalline manganese oxides (S-MnOx). These Mn-based oxides have been widely used as catalysts for the elimination of gaseous pollutants. This review aims to describe the environmental applications of these manganese oxides and provide perspectives. It gives detailed descriptions of environmental applications of the selective catalytic reduction of NOx with NH 3 , the catalytic combustion of volatile organic compounds, Hg 0 oxidation and adsorption, and soot oxidation, in addition to some other environmental applications. Furthermore, this review mainly focuses on the effects of structure, morphology, and modified elements and on the role of catalyst supports in gaseous heterogeneous catalytic reactions. Finally, future research directions for developing manganese oxide catalysts are proposed.

  17. Effects of NOx and SO2 on the secondary organic aerosol formation from photooxidation of α-pinene and limonene

    Science.gov (United States)

    Zhao, Defeng; Schmitt, Sebastian H.; Wang, Mingjin; Acir, Ismail-Hakki; Tillmann, Ralf; Tan, Zhaofeng; Novelli, Anna; Fuchs, Hendrik; Pullinen, Iida; Wegener, Robert; Rohrer, Franz; Wildt, Jürgen; Kiendler-Scharr, Astrid; Wahner, Andreas; Mentel, Thomas F.

    2018-02-01

    Anthropogenic emissions such as NOx and SO2 influence the biogenic secondary organic aerosol (SOA) formation, but detailed mechanisms and effects are still elusive. We studied the effects of NOx and SO2 on the SOA formation from the photooxidation of α-pinene and limonene at ambient relevant NOx and SO2 concentrations (NOx: biogenic volatile organic compounds (VOCs) with anthropogenic emissions.

  18. Catalytic bioreactors and methods of using same

    Science.gov (United States)

    Worden, Robert Mark; Liu, Yangmu Chloe

    2017-07-25

    Various embodiments provide a bioreactor for producing a bioproduct comprising one or more catalytically active zones located in a housing and adapted to keep two incompatible gaseous reactants separated when in a gas phase, wherein each of the one or more catalytically active zones may comprise a catalytic component retainer and a catalytic component retained within and/or thereon. Each of the catalytically active zones may additionally or alternatively comprise a liquid medium located on either side of the catalytic component retainer. Catalytic component may include a microbial cell culture located within and/or on the catalytic component retainer, a suspended catalytic component suspended in the liquid medium, or a combination thereof. Methods of using various embodiments of the bioreactor to produce a bioproduct, such as isobutanol, are also provided.

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

    Science.gov (United States)

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

    2015-12-01

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

  20. Xonon combustion system, 2,5 p.p.m NOx for gas turbines; Le processus de combustion Xonon limite les emissions des turbines a gaz a 2,5 p.p.m

    Energy Technology Data Exchange (ETDEWEB)

    Solt, Ch. [Catalytica Energy Systems Inc., California (United States)

    2001-07-01

    A gas turbine operates by compressing incoming air, combining it with fuel, and combusting the mixture. The combustion process releases the fuel's energy, forming hot gases that power the turbine. In conventional combustion systems, a flame is used to combust the fuel. The temperature required to sustain a stable flame is significantly higher than the temperature at which the gas turbine is designed to operate. This excessive temperature causes the nitrogen and oxygen in the air to react, forming nitrogen oxides (NOx), a major contributor to air pollution. We have developed Xonon{sup TM} Cool Combustion, a catalytic technology that combusts fuel flamelessly. This process releases the same amount of energy as flame-based combustion systems but at a lower temperature. Importantly, this lower temperature is below the threshold at which NOx is formed. The Xonon combustion system is the only operating catalytic combustion system demonstrated to achieve near-zero emissions. The Xonon combustion system is a pollution prevention technology that has been proven to limit emissions of NOx to less than 2.5 parts per million (ppm) without compromising the performance of the gas turbine engine. (author)

  1. Chemical kinetics with electrical and gas dynamics modelization for NOx removal in an air corona discharge

    International Nuclear Information System (INIS)

    Eichwald, O.; Guntoro, N.A.; Yousfi, M.; Benhenni, M.

    2002-01-01

    A non-stationary reactive gas dynamics model in a mono-dimensional geometry, including radial mass diffusion, gas temperature variation and chemical kinetics, is developed in this paper. The aim is to analyse the spatio-temporal evolution of the main neutral species involved in a corona discharge used for NO pollution control in polluted air at atmospheric pressure and ambient temperature. The present reactive gas dynamics model takes into account 16 neutral chemical species (including certain metastable species) reacting following 110 selected chemical reactions. The initial concentration of each neutral species is obtained from a 1.5D electrical discharge model. The gas temperature variations are due to direct Joule heating during the discharge phase, and also result from the delayed heating due to the relaxation of the vibrational energy into a random thermal energy during the post-discharge phase. The simulation conditions are those of an existing experimental setup (anode voltage of 10 kV in the case of a point to plane geometry with an interelectrode distance of 10 mm). The obtained results show that the diffusion phenomena and the gas temperature rise affect quite well the gas reactivity and the neutral species evolution. This allows us to better understand the different reaction processes and transport phenomena affecting the NO concentration magnitude inside the discharge channel. (author)

  2. 75 FR 6305 - Approval and Promulgation of Air Quality Implementation Plans; West Virginia; Removal of NOX

    Science.gov (United States)

    2010-02-09

    ... States Court of Appeals for the appropriate circuit by April 12, 2010. Filing a petition for... direct final rule are encouraged to file a comment in response to the parallel notice of proposed... Series 1 and 45CSR Series 26 in their entirety. [FR Doc. 2010-2675 Filed 2-8-10; 8:45 am] BILLING CODE...

  3. Laboratory and field studies of photocatalytic NOx and O3 removal by coatings on concrete.

    Science.gov (United States)

    2017-03-01

    This project involved thorough testing of titanium dioxide (TiO2)-containing commercial photocatalytic coatings : applied to portland cement concrete for highway applications, focusing on the use of these coatings as an : abatement method for atmosph...

  4. Alternative catalysts and technologies for NOx removal from biomass- and wastefired plants

    DEFF Research Database (Denmark)

    Schill, Leonhard

    the VWT catalyst very rapidly. Firing of biomass increased strongly over the past decade and is expected to increase even further in the near future. Also waste incineration creates ue gases that are very challenging to the SCR catalyst. Therefore, SCR units in waste incineration plants are commonly...... heavily deactivate the Ag/Al2O3 catalyst. Therefore we concluded that HC-SCR is unt for potassium containing ue gases. The eorts at developing a catalyst to be used at the tail end position were more fruitful and culminated in a patent application due to which only limited information can be disclosed...

  5. The Removal of NOx Using a Pulsed Streamer Corona Discharge in the Presence of Ethylene

    Science.gov (United States)

    1996-07-25

    gases coming out of jet engines (F101 engine with JP4 fuel) have four compounds ( ethene , acetylene, propene, and formaldehyde) accounting for 27% of...electrodes and the rod electrode on the rotating spark gap were cleaned using ethanol and sandpaper before running every experiment. The spherical...MS, 1975, Los Alamos, NM. [58] Tas, M.A, "Plasma-Induced Catalysis , A Feasibility study and fundamentals", thesis Technische Universiteit Eindhoven

  6. Catalytic activity of Au nanoparticles

    DEFF Research Database (Denmark)

    Larsen, Britt Hvolbæk; Janssens, Ton V.W.; Clausen, Bjerne

    2007-01-01

    Au is usually viewed as an inert metal, but surprisingly it has been found that Au nanoparticles less than 3–5 nm in diameter are catalytically active for several chemical reactions. We discuss the origin of this effect, focusing on the way in which the chemical activity of Au may change with par......Au is usually viewed as an inert metal, but surprisingly it has been found that Au nanoparticles less than 3–5 nm in diameter are catalytically active for several chemical reactions. We discuss the origin of this effect, focusing on the way in which the chemical activity of Au may change...

  7. Development of low NOx combustion structure in coke oven

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, S.; Takase, S.; Uchida, M.; Saji, T.; Koyama, H.; Yamamoto, M. [Sumitomo Metal Industry Ltd., Ibaraki (Japan)

    2004-09-01

    One of the targets of the SCOPE21 process was to improve the productivity. To achieve high productivity, the process was applied the following items: (1) ultra super dense brick, (2) thin wall (70 mm), (3) hot coal charging, (4) medium temperature carbonization. As the heat flux for carbonization was needed about 2 times as much as a conventional coke oven, the combustion technologies to achieve high productivity were investigated by using the actual scale combustion test oven. The combustion conditions to achieve low NOx in the waste gas and uniform heating for carbonization were clarified. The coke oven of the pilot plant was designed based on these results. The combustion targets of the low NOx and uniform heating were achieved in the test operation.

  8. Hair Removal

    DEFF Research Database (Denmark)

    Hædersdal, Merete

    2011-01-01

    Hair removal with optical devices has become a popular mainstream treatment that today is considered the most efficient method for the reduction of unwanted hair. Photothermal destruction of hair follicles constitutes the fundamental concept of hair removal with red and near-infrared wavelengths...... suitable for targeting follicular and hair shaft melanin: normal mode ruby laser (694 nm), normal mode alexandrite laser (755 nm), pulsed diode lasers (800, 810 nm), long-pulse Nd:YAG laser (1,064 nm), and intense pulsed light (IPL) sources (590-1,200 nm). The ideal patient has thick dark terminal hair......, white skin, and a normal hormonal status. Currently, no method of lifelong permanent hair eradication is available, and it is important that patients have realistic expectations. Substantial evidence has been found for short-term hair removal efficacy of up to 6 months after treatment with the available...

  9. Hair removal

    DEFF Research Database (Denmark)

    Haedersdal, Merete; Haak, Christina S

    2011-01-01

    Hair removal with optical devices has become a popular mainstream treatment that today is considered the most efficient method for the reduction of unwanted hair. Photothermal destruction of hair follicles constitutes the fundamental concept of hair removal with red and near-infrared wavelengths...... suitable for targeting follicular and hair shaft melanin: normal mode ruby laser (694 nm), normal mode alexandrite laser (755 nm), pulsed diode lasers (800, 810 nm), long-pulse Nd:YAG laser (1,064 nm), and intense pulsed light (IPL) sources (590-1,200 nm). The ideal patient has thick dark terminal hair......, white skin, and a normal hormonal status. Currently, no method of lifelong permanent hair eradication is available, and it is important that patients have realistic expectations. Substantial evidence has been found for short-term hair removal efficacy of up to 6 months after treatment with the available...

  10. DEVELOPMENT AND DEMONSTRATION OF AN ULTRA LOW NOx COMBUSTOR FOR GAS TURBINES

    Energy Technology Data Exchange (ETDEWEB)

    NEIL K. MCDOUGALD

    2005-04-30

    Alzeta Corporation has developed surface-stabilized fuel injectors for use with lean premixed combustors which provide extended turndown and ultra-low NOX emission performance. These injectors use a patented technique to form interacting radiant and blue-flame zones immediately above a selectively-perforated porous metal surface. This allows stable operation at low reaction temperatures. This technology is being commercialized under the product name nanoSTAR. Initial tests demonstrated low NOX emissions but, were limited by flashback failure of the injectors. The weld seams required to form cylindrical injectors from flat sheet material were identified as the cause of the failures. The approach for this project was to first develop new fabrication methods to produce injectors without weld seams, verify similar emissions performance to the original flat sheet material and then develop products for microturbines and small gas turbines along parallel development paths. A 37 month project was completed to develop and test a surface stabilized combustion system for gas turbine applications. New fabrication techniques developed removed a technological barrier to the success of the product by elimination of conductive weld seams from the injector surface. The injectors demonstrated ultra low emissions in rig tests conducted under gas turbine operating conditions. The ability for injectors to share a common combustion chamber allowing for deployment in annular combustion liner was also demonstrated. Some further development is required to resolve integration issues related to specific engine constraints, but the nanoSTAR technology has clearly demonstrated its low emissions potential. The overall project conclusions can be summarized: (1) A wet-laid casting method successfully eliminated weld seams from the injector surface without degrading performance. (2) Gas turbine cycle analysis identified several injector designs and control schemes to start and load engines using

  11. Low NOx Fuel Flexible Combustor Integration Project Overview

    Science.gov (United States)

    Walton, Joanne C.; Chang, Clarence T.; Lee, Chi-Ming; Kramer, Stephen

    2015-01-01

    The Integrated Technology Demonstration (ITD) 40A Low NOx Fuel Flexible Combustor Integration development is being conducted as part of the NASA Environmentally Responsible Aviation (ERA) Project. Phase 2 of this effort began in 2012 and will end in 2015. This document describes the ERA goals, how the fuel flexible combustor integration development fulfills the ERA combustor goals, and outlines the work to be conducted during project execution.

  12. Formaldehyde Production From Isoprene Oxidation Across NOx Regimes

    Science.gov (United States)

    Wolfe, G. M.; Kaiser, J.; Hanisco, T. F.; Keutsch, F. N.; de Gouw, J. A.; Gilman, J. B.; Graus, M.; Hatch, C. D.; Holloway, J.; Horowitz, L. W.; hide

    2016-01-01

    The chemical link between isoprene and formaldehyde (HCHO) is a strong, non-linear function of NOx (= NO + NO2). This relationship is a linchpin for top-down isoprene emission inventory verification from orbital HCHO column observations. It is also a benchmark for overall photochemical mechanism performance with regard to VOC oxidation. Using a comprehensive suite of airborne in situ observations over the southeast US, we quantify HCHO production across the urban-rural spectrum. Analysis of isoprene and its major first-generation oxidation products allows us to define both a prompt yield of HCHO (molecules of HCHO produced per molecule of freshly emitted isoprene) and the background HCHO mixing ratio (from oxidation of longer-lived hydrocarbons). Over the range of observed NOx values (roughly 0.1 - 2 ppbv), the prompt yield increases by a factor of 3 (from 0.3 to 0.9 ppbv ppbv(exp. -10), while background HCHO increases by a factor of 2 (from 1.6 to 3.3 ppbv). We apply the same method to evaluate the performance of both a global chemical transport model (AM3) and a measurement-constrained 0-D steady-state box model. Both models reproduce the NOx dependence of the prompt HCHO yield, illustrating that models with updated isoprene oxidation mechanisms can adequately capture the link between HCHO and recent isoprene emissions. On the other hand, both models underestimate background HCHO mixing ratios, suggesting missing HCHO precursors, inadequate representation of later-generation isoprene degradation and/or underestimated hydroxyl radical concentrations. Detailed process rates from the box model simulation demonstrate a 3-fold increase in HCHO production across the range of observed NOx values, driven by a 100% increase in OH and a 40% increase in branching of organic peroxy radical reactions to produce HCHO.

  13. Plasma-catalytic decomposition of TCE

    Energy Technology Data Exchange (ETDEWEB)

    Vandenbroucke, A.; Morent, R.; De Geyter, N.; Leys, C. [Ghent Univ., Ghent (Belgium). Dept. of Applied Physics; Tuan, N.D.M.; Giraudon, J.M.; Lamonier, J.F. [Univ. des Sciences et Technologies de Lille, Villeneuve (France). Dept. de Catalyse et Chimie du Solide

    2010-07-01

    Volatile organic compounds (VOCs) are gaseous pollutants that pose an environmental hazard due to their high volatility and their possible toxicity. Conventional technologies to reduce the emission of VOCs have their advantages, but they become cost-inefficient when low concentrations have to be treated. In the past 2 decades, non-thermal plasma technology has received growing attention as an alternative and promising remediation method. Non-thermal plasmas are effective because they produce a series of strong oxidizers such as ozone, oxygen radicals and hydroxyl radicals that provide a reactive chemical environment in which VOCs are completely oxidized. This study investigated whether the combination of NTP and catalysis could improve the energy efficiency and the selectivity towards carbon dioxide (CO{sub 2}). Trichloroethylene (TCE) was decomposed by non-thermal plasma generated in a DC-excited atmospheric pressure glow discharge. The production of by-products was qualitatively investigated through FT-IR spectrometry. The results were compared with those from a catalytic reactor. The removal rate of TCE reached a maximum of 78 percent at the highest input energy. The by-products of TCE decomposition were CO{sub 2}, carbon monoxide (CO) hydrochloric acid (HCl) and dichloroacetylchloride. Combining the plasma system with a catalyst located in an oven downstream resulted in a maximum removal of 80 percent, at an energy density of 300 J/L, a catalyst temperature of 373 K and a total air flow rate of 2 slm. 14 refs., 6 figs.

  14. NOx Control Options and Integration for US Coal Fired Boilers

    Energy Technology Data Exchange (ETDEWEB)

    Mike Bockelie; Kevin Davis; Temi Linjewile; Connie Senior; Eric Eddings; Kevin Whitty; Larry Baxter; Calvin Bartholomew; William Hecker; Stan Harding

    2004-03-31

    This is the fifteenth Quarterly Technical Report for DOE Cooperative Agreement No: DE-FC26-00NT40753. The goal of the project is to develop cost effective analysis tools and techniques for demonstrating and evaluating low NOx control strategies and their possible impact on boiler performance for boilers firing US coals. The Electric Power Research Institute (EPRI) is providing co-funding for this program. At AEP's Gavin Plant, data from the corrosion probes showed that corrosion rate increased as boiler load was increased. During an outage at the plant, the drop in boiler load, sensor temperature and corrosion rate could all be seen clearly. Restarting the boiler saw a resumption of corrosion activity. This behavior is consistent with previous observations made at a 600MWe utility boiler. More data are currently being examined for magnitudes of corrosion rates and changes in boiler operating conditions. Considerable progress was made this quarter in BYU's laboratory study of catalyst deactivation. Surface sulfation appears to partially suppress NO adsorption when the catalyst is not exposed to NH3; NH3 displaces surface-adsorbed NO on SCR catalysts and surface sulfation increases the amount of adsorbed NH3, as confirmed by both spectroscopy and TPD experiments. However, there is no indication of changes in catalyst activity despite changes in the amount of adsorbed NH3. A monolith test reactor (MTR), completed this quarter, provided the first comparative data for one of the fresh and field-exposed monolith SCR catalysts yet developed in this project. Measurements of activity on one of the field-exposed commercial monolith catalysts do not show significant changes in catalyst activity (within experimental error) as compared to the fresh catalyst. The exposed surface of the sample contains large amounts of Ca and Na, neither of which is present in the fresh sample, even after removal of visibly obvious fouling deposits. However, these fouling compounds do

  15. OZONE PRODUCTION EFFICIENCY AND NOX DEPLETION IN AN URBAN PLUME: INTERPRETATION OF FIELD OBSERVATIONS AND IMPLICATIONS FOR EVALUATING O3-NOX-VOC SENSITIVITY

    Science.gov (United States)

    Ozone production efficiency (OPE) can be defined as the number of ozone (O3) molecules photochemically produced by a molecule of NOx (NO + NO2) before it is lost from the NOx - O3 cycle. Here, we consider observational and modeling techniques to evaluate various operational defi...

  16. Measurements of NOx precursor concentration profile above the bed at a full scale W-t-E plant and the effect of precursor speciation on the NOx formation

    DEFF Research Database (Denmark)

    Jepsen, Morten Søe; Jensen, Peter Arendt; Fateev, Alexander

    Satisfactory result from CFD modelling of NOx formation during combustion of waste in grate-fired waste-to-energy plants relies heavily on an accurate description of the temperature field in the free-board, this is a consequence of the high dependency of the temperature on the fuel NOx chemistry [1...

  17. A structural basis for the regulation of an H-NOX-associated cyclic-di-GMP synthase/phosphodiesterase enzyme by nitric oxide-bound H-NOX.

    Science.gov (United States)

    Lahiri, Tanaya; Luan, Bowu; Raleigh, Daniel P; Boon, Elizabeth M

    2014-04-08

    Biofilms are surface-attached communities of bacteria enclosed in a polysaccharide matrix. Bacteria in a biofilm are extremely resistant to antibiotics. Several recent reports have linked the signaling molecule nitric oxide (NO) with biofilm dispersal. We have previously reported that an H-NOX (heme-nitric oxide/oxygen binding) protein in the biofilm-dwelling bacterium Shewanella woodyi mediates NO-induced biofilm dispersal. In S. woodyi, H-NOX (SwH-NOX) is cocistronic with a gene encoding a dual-functioning diguanylate cyclase/phosphodiesterase enzyme, designated here as HaCE (H-NOX-associated cyclic-di-GMP processing enzyme). Enzymes such as these are responsible for regulating the intracellular concentrations of cyclic-di-GMP, a secondary signaling molecule essential to biofilm formation in bacteria. We have demonstrated that NO-bound SwH-NOX regulates both enzymatic activities of SwHaCE, resulting in decreased cellular cyclic-di-GMP levels and disruption of biofilm formation. Thus, H-NOX/HaCE represents a potential drug target for regulating biofilm formation. In this work, the SwH-NOX surface residues critical for the formation of a protein complex with SwHaCE are identified using nuclear magnetic resonance, fluorescence quenching, and cosedimentation. Enzyme assays confirm this protein-protein interface and its importance for H-NOX/HaCE function.

  18. Marginal abatement cost curves for NOx that account for ...

    Science.gov (United States)

    A marginal abatement cost curve (MACC) traces out the relationship between the quantity of pollution abated and the marginal cost of abating each additional unit. In the context of air quality management, MACCs typically are developed by sorting end-of-pipe controls by their respective cost effectiveness. Alternative measures, such as renewable electricity, energy efficiency, and fuel switching (RE/EE/FS), are not considered as it is difficult to quantify their abatement potential. In this paper, we demonstrate the use of an energy system model to develop a MACC for nitrogen oxides (NOx) that incorporates both end-of-pipe controls and these alternative measures. We decompose the MACC by sector, and evaluate the cost-effectiveness of RE/EE/FS relative to end-of-pipe controls. RE/EE/FS are shown to produce considerable emission reductions after end-of-pipe controls have been exhausted. Furthermore, some RE/EE/FS are shown to be cost-competitive with end-of-pipe controls. Demonstrate how the MARKAL energy system model can be used to evaluate the potential role of renewable electricity, energy efficiency and fuel switching (RE/EE/FS) in achieving NOx reductions. For this particular analysis, we show that RE/EE/FSs are able to increase the quantity of NOx reductions available for a particular marginal cost (ranging from $5k per ton to $40k per ton) by approximately 50%.

  19. A Pilot-Scale Evaluation of a New Technology to Control NO(x) Emissions from Boilers at KSC: Hydrogen Peroxide Injection into Boiler Flue Gases Followed by Wet Scrubbing of Acid Gases

    Science.gov (United States)

    Cooper, C. David

    1997-01-01

    Emissions of nitrogen oxides NO(x) are a significant problem in the United States. NO(x) are formed in any combustion process, therefore it is not surprising that NO(x) are emitted from the boilers at KSC. Research at UCF has shown (in the laboratory) that injecting H2O2 into hot simulated flue gases can oxidize the NO and NO2 to their acid gas forms, HNO2 and HNO3, respectively. These acid gases are much more water soluble than their counterparts, and theoretically can be removed easily by wet scrubbing. This technology was of interest to NASA, both for their boilers at KSC, and for their combustion sources elsewhere. However, it was necessary to field test the technology and to provide pilot-scale data to aid in design of full-scale facilities. Hence this project was initiated in May of 1996.

  20. The protective effect and diagnostic performance of NOX-5 in Crimean-Congo haemorrhagic fever patients.

    Science.gov (United States)

    Büyüktuna, Seyit Ali; Doğan, Halef Okan; Bakir, Mehmet; Elaldi, Nazif; Gözel, Mustafa Gökhan; Engin, Aynur

    2018-04-01

    Crimean-Congo haemorrhagic fever (CCHF) is an acute viral haemorrhagic disease. Reactive oxygen species that are mainly generated by the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX) enzyme family have a pivotal role in the pathophysiology of many diseases. The serum levels of NOX isoforms in patients with CCHF have yet to be assessed. This prospective study was conducted at Cumhuriyet University, Turkey. Only patients with CCHF confirmed by the National Reference Virology Laboratory were enrolled in the study. The study subjects comprised 67 CCHF patients and 70 healthy control subjects. The quantitative sandwich ELISA technique was used for the determination of serum NOX 1, 2, 4 and 5. Higher median median NOX-1 (P=0.001) and NOX-5 (PNOX-5 levels were found in the low-grade disease group compared to the intermediate-high disease group according to two different severity scores (P=0.003). Negative correlations were also found between the serum NOX-5 levels and the severity scores [(PNOX-1 and NOX-5 were 0.67 (confidence interval: 0.58-0.75) and 0.99 (confidence interval: 0.95-1.00), respectively. Lower NOX-5 levels were found in patients receiving thrombocyte suspension (P=0.004)Conclusions. NOX-5 may have a protective effect on CCHF patients and the measurement of serum NOX-5 levels may be used as a novel biochemical test in the diagnosis of CCHF.

  1. Regulation of Nox enzymes expression in vascular pathophysiology: Focusing on transcription factors and epigenetic mechanisms.

    Science.gov (United States)

    Manea, Simona-Adriana; Constantin, Alina; Manda, Gina; Sasson, Shlomo; Manea, Adrian

    2015-08-01

    NADPH oxidases (Nox) represent a family of hetero-oligomeric enzymes whose exclusive biological function is the generation of reactive oxygen species (ROS). Nox-derived ROS are essential modulators of signal transduction pathways that control key physiological activities such as cell growth, proliferation, migration, differentiation, and apoptosis, immune responses, and biochemical pathways. Enhanced formation of Nox-derived ROS, which is generally associated with the up-regulation of different Nox subtypes, has been established in various pathologies, namely cardiovascular diseases, diabetes, obesity, cancer, and neurodegeneration. The detrimental effects of Nox-derived ROS are related to alterations in cell signalling and/or direct irreversible oxidative damage of nucleic acids, proteins, carbohydrates, and lipids. Thus, understanding of transcriptional regulation mechanisms of Nox enzymes have been extensively investigated in an attempt to find ways to counteract the excessive formation of Nox-derived ROS in various pathological states. Despite the numerous existing data, the molecular pathways responsible for Nox up-regulation are not completely understood. This review article summarizes some of the recent advances and concepts related to the regulation of Nox expression in the vascular pathophysiology. It highlights the role of transcription factors and epigenetic mechanisms in this process. Identification of the signalling molecules involved in Nox up-regulation, which is associated with the onset and development of cardiovascular dysfunction may contribute to the development of novel strategies for the treatment of cardiovascular diseases. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

  2. NOX4 supports glycolysis and promotes glutamine metabolism in non-small cell lung cancer cells.

    Science.gov (United States)

    Zeng, Cheng; Wu, Qipeng; Wang, Jing; Yao, Bei; Ma, Lei; Yang, Zhicheng; Li, Juan; Liu, Bing

    2016-12-01

    Our previous studies have confirmed that NADPH oxidase 4 (NOX4) is abundantly expressed in non-small cell lung cancer (NSCLC) and contributes to cancer progression. Nevertheless, the comprehensive mechanisms for NOX4-mediated malignant progression and oxidative resistance of cancer cells remain largely unknown. This study found that NOX4 directed glucose metabolism not only to the glycolysis but also to pentose phosphate pathway (PPP) pathway for production of NADPH in NSCLC cell lines. Besides, we also found that NOX4 promoted glutaminolysis into total GSH synthesis. Specifically, the data showed that ectopic NOX4 expression did not induce apoptosis of NSCLC cells; however, inhibition of GSH production resulted in obvious apoptotic death of NOX4-overexpressed NSCLC cells. Furthermore, we demonstrated that NOX4-induced glycolysis probably via ROS/PI3K/Akt signaling-dependent c-Myc upregulation. The selective NOX4 inhibitor, GKT137831, significantly inhibited glucose and glutamine metabolic phenotypes both in vitro and in vivo, and itself or combination with 2-DG, a synthetic glycolytic inhibitor, suppressed cancer cell growth both in vivo and in vitro. Elimination of NOX4-derived H 2 O 2 effectively reversed NOX4 overexpression-mediated metabolic effects in NSCLC cells. NOX4 levels were significantly correlated with increased glucose and glutamine metabolism-related genes, as well as Akt phosphorylation and c-Myc expression in primary NSCLC specimens. In conclusion, these results reveal that NOX4 promotes glycolysis, contributing to NSCLC growth, and supports glutaminolysis for oxidative resistance. Therefore, NOX4 may be a promising target to reverse malignant progression of NSCLC. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. Determination of the NOx Loading of an Automotive Lean NOx Trap by Directly Monitoring the Electrical Properties of the Catalyst Material Itself

    Science.gov (United States)

    Fremerey, Peter; Reiß, Sebastian; Geupel, Andrea; Fischerauer, Gerhard; Moos, Ralf

    2011-01-01

    Recently, it has been shown that the degree of loading of several types of automotive exhaust aftertreatment devices can be directly monitored in situ and in a contactless way by a microwave-based method. The goal of this study was to clarify whether this method can also be applied to NOx storage and reduction catalysts (lean NOx traps) in order to obtain further knowledge about the reactions occurring in the catalyst and to compare the results with those obtained by wirebound NOx loading sensors. It is shown that both methods are able to detect the different catalyst loading states. However, the sensitivity of the microwave-based method turned out to be small compared to that previously observed for other exhaust aftertreatment devices. This may limit the practical applicability of the microwave-based NOx loading detection in lean NOx traps. PMID:22164074

  4. Engineering reactors for catalytic reactions

    Indian Academy of Sciences (India)

    ... improvements in reactor performance. In this article, application of recent (and not so recent) developments in engineering reactors for catalytic reactions is discussed. Some examples where performance enhancement was realized by catalyst design, appropriate choice of reactor, better injection and dispersion strategies ...

  5. Catalytic properties of niobium compounds

    International Nuclear Information System (INIS)

    Tanabe, K.; Iizuka, T.

    1983-04-01

    The catalytic activity and selectivity of niobium compounds including oxides, salts, organometallic compounds and others are outlined. The application of these compounds as catalysts to diversified reactions is reported. The nature and action of niobium catalysts are characteristic and sometimes anomalous, suggesting the necessity of basic research and the potential use as catalysts for important processes in the chemical industry. (Author) [pt

  6. Catalytic carboxyester hydrolysis by diaminodiphenols

    Indian Academy of Sciences (India)

    Administrator

    Two diaminodiphenols, 1 and 2, have been examined as catalysts for the hydrolysis of 4- nitrophenyl acetate (NA) and 4-nitrophenylphosphate (NP) in aqueous-acetonitrile (25% acetonitrile v/v) media at 35ºC, I = 1·0 mol dm–3. The compound 1 enhances the hydrolysis rate of NA more than 105 times. Its catalytic efficiency ...

  7. Engineering reactors for catalytic reactions

    Indian Academy of Sciences (India)

    on selectivity can make substantial impact on process viability and economics. Extensive studies have been conducted to establish sound basis for design and engineering of reactors for practising such catalytic reactions and for realizing improvements in reactor performance. In this article, application of recent (and not so ...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2001-12-21

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

  9. Estimates of lightning NOx production from GOME satellite observations

    Directory of Open Access Journals (Sweden)

    K. F. Boersma

    2005-01-01

    Full Text Available Tropospheric NO2 column retrievals from the Global Ozone Monitoring Experiment (GOME satellite spectrometer are used to quantify the source strength and 3-D distribution of lightning produced nitrogen oxides (NOx=NO+NO2. A sharp increase of NO2 is observed at convective cloud tops with increasing cloud top height, consistent with a power-law behaviour with power 5±2. Convective production of clouds with the same cloud height are found to produce NO2 with a ratio 1.6/1 for continents compared to oceans. This relation between cloud properties and NO2 is used to construct a 10:30 local time global lightning NO2 production map for 1997. An extensive statistical comparison is conducted to investigate the capability of the TM3 chemistry transport model to reproduce observed patterns of lightning NO2 in time and space. This comparison uses the averaging kernel to relate modelled profiles of NO2 to observed NO2 columns. It exploits a masking scheme to minimise the interference of other NOx sources on the observed total columns. Simulations are performed with two lightning parameterizations, one relating convective preciptation (CP scheme to lightning flash distributions, and the other relating the fifth power of the cloud top height (H5 scheme to lightning distributions. The satellite-retrieved NO2 fields show significant correlations with the simulated lightning contribution to the NO2 concentrations for both parameterizations. Over tropical continents modelled lightning NO2 shows remarkable quantitative agreement with observations. Over the oceans however, the two model lightning parameterizations overestimate the retrieved NO2 attributed to lightning. Possible explanations for these overestimations are discussed. The ratio between satellite-retrieved NO2 and modelled lightning NO2 is used to rescale the original modelled lightning NOx production. Eight estimates of the lightning NOx production in 1997 are obtained from spatial and temporal

  10. Application of the NOx Reaction Model for Development of Low-NOx Combustion Technology for Pulverized Coals by Using the Gas Phase Stoichiometric Ratio Index

    Directory of Open Access Journals (Sweden)

    Kenji Yamamoto

    2011-03-01

    Full Text Available We previously proposed the gas phase stoichiometric ratio (SRgas as an index to evaluate NOx concentration in fuel-rich flames. The SRgas index was defined as the amount of fuel required for stoichiometric combustion/amount of gasified fuel, where the amount of gasified fuel was the amount of fuel which had been released to the gas phase by pyrolysis, oxidation and gasification reactions. In the present study we found that SRgas was a good index to consider the gas phase reaction mechanism in fuel-rich pulverized coal flames. When SRgas < 1.0, NOx concentration was strongly influenced by the SRgas value. NOx concentration was also calculated by using a reaction model. The model was verified for various coals, particle diameters, reaction times, and initial oxygen concentrations. The most important reactions were gas phase NOx reduction reactions by hydrocarbons. The hydrocarbon concentration was estimated based on SRgas. We also investigated the ratio as an index to develop a new low-NOx combustion technology for pulverized coals. We examined the relation between local SRgas distribution in the fuel-rich region in the low-NOx flame and NOx emissions at the furnace exit, by varying burner structures. The relationship between local SRgas value and local NOx concentration was also examined. When a low-NOx type burner was used, the value of SRgas in the flame was readily decreased. When the local SRgas value was the same, it was difficult to influence the local NOx concentration by changing the burner structure. For staged combustion, the most important item was to design the burner structure and arrangement so that SRgas could be lowered as much as possible just before mixing with staged air.

  11. H-NOX from Clostridium botulinum, like H-NOX from Thermoanaerobacter tengcongensis, Binds Oxygen but with a Less Stable Oxyferrous Heme Intermediate.

    Science.gov (United States)

    Wu, Gang; Liu, Wen; Berka, Vladimir; Tsai, Ah-Lim

    2015-12-08

    Heme nitric oxide/oxygen binding protein isolated from the obligate anaerobe Clostridium botulinum (Cb H-NOX) was previously reported to bind NO with a femtomolar K(D) (Nioche, P. et al. Science 2004, 306, 1550-1553). On the other hand, no oxyferrous Cb H-NOX was observed despite full conservation of the key residues that stabilize the oxyferrous complex in the H-NOX from Thermoanaerobacter tengcongensis (Tt H-NOX) (the same study). In this study, we re-measured the kinetics/affinities of Cb H-NOX for CO, NO, and O2. K(D)(CO) for the simple one-step equilibrium binding was 1.6 × 10(-7) M. The K(D)(NO) of Cb H-NOX was 8.0 × 10(-11) M for the first six-coordinate NO complex, and the previous femtomolar K(D)(NO) was actually an apparent K(D) for its multiple-step NO binding. An oxyferrous Cb H-NOX was clearly observed with a K(D)(O2) of 5.3 × 10(-5) M, which is significantly higher than Tt H-NOX's K(D)(O2) = 4.4 × 10(-8) M. The gaseous ligand binding of Cb H-NOX provides another supportive example for the "sliding scale rule" hypothesis (Tsai, A.-L. et al. Antioxid. Redox Signal. 2012, 17, 1246-1263), and the presence of hydrogen bond donor Tyr139 in Cb H-NOX selectively enhanced its affinity for oxygen.

  12. Catalytic ozonation of sulfamethoxazole by composite iron-manganese silicate oxide: cooperation mechanism between adsorption and catalytic reaction.

    Science.gov (United States)

    Gao, Guoying; Kang, Jing; Shen, Jimin; Chen, Zhonglin; Chu, Wei

    2016-11-01

    A systematic investigation of the cooperation mechanism between adsorption and catalytic reaction during the catalytic ozonation of sulfamethoxazole (SMX) by composite iron-manganese silicate oxide (FMSO) was carried out in this work. Results showed that the total organic carbon (TOC) removal increased significantly from 27 % (sole-ozonation) to 79.8 % (FMSO catalytic ozonation). The presence of FMSO in the ozonation process effectively enhanced the ozone utilization efficiency and accelerated the transformation of ozone into hydroxyl radicals. The latter result was verified by the indirect method, using NaHSO 3 as the reductor, and the direct electron spin resonance (ESR) determination technology. The adsorption of SMX on FMSO was minimal (1.8 %). However, ozone rapidly converted SMX into various intermediates, which was exhibited by the much higher adsorption affinity on the surface of FMSO than that of SMX. The accumulation of various intermediates on the FMSO surface also increased their contact probability with the ·OH radicals generated by the ozone decomposition. The continuous interaction of intermediates with ·OH radicals could further promote the benign cycling of the release of adsorption sites and the succeeding adsorption/decomposition of ozone and intermediates on FMSO. This could be another reason for the higher and faster TOC removal rate.

  13. Coal hydrogenation and deashing in ebullated bed catalytic reactor

    Science.gov (United States)

    Huibers, Derk T. A.; Johanson, Edwin S.

    1983-01-01

    An improved process for hydrogenation of coal containing ash with agglomeration and removal of ash from an ebullated bed catalytic reactor to produce deashed hydrocarbon liquid and gas products. In the process, a flowable coal-oil slurry is reacted with hydrogen in an ebullated catalyst bed reaction zone at elevated temperature and pressure conditions. The upward velocity and viscosity of the reactor liquid are controlled so that a substantial portion of the ash released from the coal is agglomerated to form larger particles in the upper portion of the reactor above the catalyst bed, from which the agglomerated ash is separately withdrawn along with adhering reaction zone liquid. The resulting hydrogenated hydrocarbon effluent material product is phase separated to remove vapor fractions, after which any ash remaining in the liquid fraction can be removed to produce substantially ash-free coal-derived liquid products.

  14. Research progress of siloxane removal from biogas

    Directory of Open Access Journals (Sweden)

    Gao Ruiling

    2017-01-01

    Full Text Available Siloxanes in biogas are detrimental to engine, turbine, fuel cell, etc., thus it is necessary to remove siloxanes from biogas before biogas high-value utilization. At present, there are few domestic researches and related reports in view of siloxanes removal from biogas. This paper introduces the property of siloxanes as well as sampling and analysis method, and then presents the research progress of siloxanes removal from biogas. Three commercial technologies overseas are adsorption, absorption and cryogenic condensation. Among them, adsorption on activated carbon is the most widely used method. Other technologies, such as biological removal, catalytic processes, membranes, source controlling, etc. are under exploration and development. At last, this paper summarizes the advantages and disadvantages of siloxanes removal technologies as well as the applicability and analyzes the future research trend and emphasis. This paper could provide a reference in the field of biogas high-value utilization.

  15. Removing Bureaucracy

    Science.gov (United States)

    2015-08-01

    11 Defense AT&L: July–August 2015 Removing Bureaucracy Katharina G. McFarland McFarland is Assistant Secretary of Defense for Acquisition. I once...involvement from all of the Service warfighting areas came together to scrub the program requirements due to concern over the “ bureaucracy ” and... Bureaucracy ” that focuses on reducing cycle time, staffing time and all forms of inefficiencies. This includes review of those burdens that Congress

  16. Nrf2 mediates redox adaptation in NOX4-overexpressed non-small cell lung cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Qipeng; Yao, Bei; Li, Ning; Ma, Lei; Deng, Yanchao; Yang, Yang; Zeng, Cheng; Yang, Zhicheng [Department of Clinical Pharmacy, School of Pharmacy, Guangdong Pharmaceutical University, Guangzhou 510006 (China); Liu, Bing, E-mail: liubing520@gdpu.edu.cn [Department of Clinical Pharmacy, School of Pharmacy, Guangdong Pharmaceutical University, Guangzhou 510006 (China); Guangdong Key Laboratory of Pharmaceutical Bioactive Substances, Guangdong Pharmaceutical University, Guangzhou 510006 (China)

    2017-03-15

    The redox adaptation mechanisms in cancer cells are very complex and remain largely unclear. Our previous studies have confirmed that NADPH oxidase 4 (NOX4) is abundantly expressed in non-small cell lung cancer (NSCLC) and confers apoptosis resistance on NSCLC cells. However, the comprehensive mechanisms for NOX4-mediated oxidative resistance of cancer cells remain still undentified. The present study found that NOX4-derived H{sub 2}O{sub 2} enhanced the nuclear factor erythroid 2-related factor 2 (Nrf2) stability via disruption of redox-dependent proteasomal degradation and stimulated its activity through activation of PI3K signaling. Specifically, the results showed that ectopic NOX4 expression did not induce apoptosis of A549 cells; however, inhibition of Nrf2 resulted in obvious apoptotic death of NOX4-overexpressed A549 cells, accompanied by a significant increase in H{sub 2}O{sub 2} level and decrease in GSH content. Besides, inhibition of Nrf2 could suppress cell growth and efficiently reverse the enhancement effect of NOX4 on cell growth. The in vivo data confirmed that inhibition of Nrf2 could interfere apoptosis resistance in NOX4-overexpressed A549 tumors and led to cell growth inhibition. In conclusion, these results reveal that Nrf2 is critically involved in redox adaptation regulation in NOX4-overexpressed NSCLC cells. Therefore, NOX4 and Nrf2 may be promising combination targets against malignant progression of NSCLC. - Highlights: • NOX4-derived H{sub 2}O{sub 2} upregulates Nrf2 expression and activity in NSCLC. • Nrf2 confers apoptosis resistance in NOX4-overexpressed NSCLC cells. • Inhibition of Nrf2 reverses the enhancement effect of NOX4 on cell growth.

  17. Nrf2 mediates redox adaptation in NOX4-overexpressed non-small cell lung cancer cells

    International Nuclear Information System (INIS)

    Wu, Qipeng; Yao, Bei; Li, Ning; Ma, Lei; Deng, Yanchao; Yang, Yang; Zeng, Cheng; Yang, Zhicheng; Liu, Bing

    2017-01-01

    The redox adaptation mechanisms in cancer cells are very complex and remain largely unclear. Our previous studies have confirmed that NADPH oxidase 4 (NOX4) is abundantly expressed in non-small cell lung cancer (NSCLC) and confers apoptosis resistance on NSCLC cells. However, the comprehensive mechanisms for NOX4-mediated oxidative resistance of cancer cells remain still undentified. The present study found that NOX4-derived H 2 O 2 enhanced the nuclear factor erythroid 2-related factor 2 (Nrf2) stability via disruption of redox-dependent proteasomal degradation and stimulated its activity through activation of PI3K signaling. Specifically, the results showed that ectopic NOX4 expression did not induce apoptosis of A549 cells; however, inhibition of Nrf2 resulted in obvious apoptotic death of NOX4-overexpressed A549 cells, accompanied by a significant increase in H 2 O 2 level and decrease in GSH content. Besides, inhibition of Nrf2 could suppress cell growth and efficiently reverse the enhancement effect of NOX4 on cell growth. The in vivo data confirmed that inhibition of Nrf2 could interfere apoptosis resistance in NOX4-overexpressed A549 tumors and led to cell growth inhibition. In conclusion, these results reveal that Nrf2 is critically involved in redox adaptation regulation in NOX4-overexpressed NSCLC cells. Therefore, NOX4 and Nrf2 may be promising combination targets against malignant progression of NSCLC. - Highlights: • NOX4-derived H 2 O 2 upregulates Nrf2 expression and activity in NSCLC. • Nrf2 confers apoptosis resistance in NOX4-overexpressed NSCLC cells. • Inhibition of Nrf2 reverses the enhancement effect of NOX4 on cell growth.

  18. Understanding NOx SCR Mechanism and Activity on Cu/Chabazite Structures throughout the Catalyst Life Cycle

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, Fabio; Delgass, Nick; Gounder, Rajmani; Schneider, William F.; Miller, Jeff; Yezerets, Aleksey; McEwen, Jean-Sabin; Peden, Charles HF; Howden, Ken

    2014-12-09

    Oxides of nitrogen (NOx) compounds contribute to acid rain and photochemical smog and have been linked to respiratory ailments. NOx emissions regulations continue to tighten, driving the need for high performance, robust control strategies. The goal of this project is to develop a deep, molecular level understanding of the function of Cu-SSZ-13 and Cu-SAPO-34 materials that catalyze the SCR of NOx with NH3.

  19. Dosimeter-type NOx sensing properties of KMnO4 and its electrical conductivity during temperature programmed desorption.

    Science.gov (United States)

    Groß, Andrea; Kremling, Michael; Marr, Isabella; Kubinski, David J; Visser, Jacobus H; Tuller, Harry L; Moos, Ralf

    2013-04-02

    An impedimetric NOx dosimeter based on the NOx sorption material KMnO4 is proposed. In addition to its application as a low level NOx dosimeter, KMnO4 shows potential as a precious metal free lean NOx trap material (LNT) for NOx storage catalysts (NSC) enabling electrical in-situ diagnostics. With this dosimeter, low levels of NO and NO2 exposure can be detected electrically as instantaneous values at 380 °C by progressive NOx accumulation in the KMnO4 based sensitive layer. The linear NOx sensing characteristics are recovered periodically by heating to 650 °C or switching to rich atmospheres. Further insight into the NOx sorption-dependent conductivity of the KMnO4-based material is obtained by the novel eTPD method that combines electrical characterization with classical temperature programmed desorption (TPD). The NOx loading amount increases proportionally to the NOx exposure time at sorption temperature. The cumulated NOx exposure, as well as the corresponding NOx loading state, can be detected linearly by electrical means in two modes: (1) time-continuously during the sorption interval including NOx concentration information from the signal derivative or (2) during the short-term thermal NOx release.

  20. Dosimeter-Type NOx Sensing Properties of KMnO4 and Its Electrical Conductivity during Temperature Programmed Desorption

    Directory of Open Access Journals (Sweden)

    Ralf Moos

    2013-04-01

    Full Text Available An impedimetric NOx dosimeter based on the NOx sorption material KMnO4 is proposed. In addition to its application as a low level NOx dosimeter, KMnO4 shows potential as a precious metal free lean NOx trap material (LNT for NOx storage catalysts (NSC enabling electrical in-situ diagnostics. With this dosimeter, low levels of NO and NO2 exposure can be detected electrically as instantaneous values at 380 °C by progressive NOx accumulation in the KMnO4 based sensitive layer. The linear NOx sensing characteristics are recovered periodically by heating to 650 °C or switching to rich atmospheres. Further insight into the NOx sorption-dependent conductivity of the KMnO4-based material is obtained by the novel eTPD method that combines electrical characterization with classical temperature programmed desorption (TPD. The NOx loading amount increases proportionally to the NOx exposure time at sorption temperature. The cumulated NOx exposure, as well as the corresponding NOx loading state, can be detected linearly by electrical means in two modes: (1 time-continuously during the sorption interval including NOx concentration information from the signal derivative or (2 during the short-term thermal NOx release.