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Sample records for selective nox recirculation

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

    Energy Technology Data Exchange (ETDEWEB)

    Nigel N. Clark

    2006-12-31

    Nitric oxide (NO) and nitrogen dioxide (NO2) generated by internal combustion (IC) engines are implicated in adverse environmental and health effects. Even though lean-burn natural gas engines have traditionally emitted lower oxides of nitrogen (NOx) emissions compared to their diesel counterparts, natural gas engines are being further challenged to reduce NOx emissions to 0.1 g/bhp-hr. The Selective NOx Recirculation (SNR) approach for NOx reduction involves cooling the engine exhaust gas and then adsorbing the NOx from the exhaust stream, followed by the periodic desorption of NOx. By sending the desorbed NOx back into the intake and through the engine, a percentage of the NOx can be decomposed during the combustion process. SNR technology has the support of the Department of Energy (DOE), under the Advanced Reciprocating Engine Systems (ARES) program to reduce NOx emissions to under 0.1 g/bhp-hr from stationary natural gas engines by 2010. The NO decomposition phenomenon was studied using two Cummins L10G natural gas fueled spark-ignited (SI) engines in three experimental campaigns. It was observed that the air/fuel ratio ({lambda}), injected NO quantity, added exhaust gas recirculation (EGR) percentage, and engine operating points affected NOx decomposition rates within the engine. Chemical kinetic model predictions using the software package CHEMKIN were performed to relate the experimental data with established rate and equilibrium models. The model was used to predict NO decomposition during lean-burn, stoichiometric burn, and slightly rich-burn cases with added EGR. NOx decomposition rates were estimated from the model to be from 35 to 42% for the lean-burn cases and from 50 to 70% for the rich-burn cases. The modeling results provided an insight as to how to maximize NOx decomposition rates for the experimental engine. Results from this experiment along with chemical kinetic modeling solutions prompted the investigation of rich-burn operating conditions

  2. 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

    Selective NOx Recirculation (SNR) involves cooling the engine exhaust gas and then adsorbing the oxides of nitrogen (NOx) from the exhaust stream, followed by the periodic desorption of NOx. By returning the desorbed, concentrated NOx into the engine intake and through the combustion chamber, a percentage of the NOx is decomposed during the combustion process. An initial study of NOx decomposition during lean-burn combustion was concluded in 2004 using a 1993 Cummins L10G 240hp natural gas engine. It was observed that the air/fuel ratio, injected NO (nitric oxide) quantity and engine operating points affected NOx decomposition rates of the engine. Chemical kinetic modeling results were also used to determine optimum NOx decomposition operating points and were published in the 2004 annual report. A NOx decomposition rate of 27% was measured from this engine under lean-burn conditions while the software model predicted between 35-42% NOx decomposition for similar conditions. A later technology 1998 Cummins L10G 280hp natural gas engine was procured with the assistance of Cummins Inc. to replace the previous engine used for 2005 experimental research. The new engine was equipped with an electronic fuel management system with closed-loop control that provided a more stable air/fuel ratio control and improved the repeatability of the tests. The engine was instrumented with an in-cylinder pressure measurement system and electronic controls, and was adapted to operate over a range of air/fuel ratios. The engine was connected to a newly commissioned 300hp alternating current (AC) motoring dynamometer. The second experimental campaign was performed to acquire both stoichiometric and slightly rich (0.97 lambda ratio) burn NOx decomposition rates. Effects of engine load and speed on decomposition were quantified, but Exhaust Gas Recirculation (EGR) was not varied independently. Decomposition rates of up to 92% were demonstrated. Following recommendations at the 2004 ARES peer

  3. Exhaust Recirculation Control for Reduction of NOx from Large Two-Stroke Diesel Engines

    DEFF Research Database (Denmark)

    Nielsen, Kræn Vodder

    Increased awareness of the detrimental effects on climate, ecosystems and human health have led to numerous restrictions of the emissions from internal combustion engines. Recently the International Maritime Organization has introduced the Tier III standard, which includes a significantly stricter...... the automotive industry, but have only recently been introduced commercially to large two-stroke diesel engines. Recirculation of exhaust gas to the cylinders lowers the oxygen availability and increases the heat capacity during combustion, which in turn leads to less formation of NOx. Experience shows...... of the Tier III standard, while still maintaining maneuverability performance without smoke formation. The design methods acknowledge that engine specific parameter tuning is a scarce resource in the industry and controller complexity is kept to a minimum. An existing dynamic model of the engine and EGR...

  4. Studi Experimental Penggunaan Venturi Scrubber dan Cyclonic Separator Untuk Meningkatkan Kinerja pada Sistem Exhaust Gas Recirculation (EGR dalam Menurunkan NOX pada Motor Diesel

    Directory of Open Access Journals (Sweden)

    Samsu Dlukha N

    2012-09-01

    Full Text Available Salah satu cara yang efektif untuk mengurangi NOX adalah dengan menggunakan metode Exhaust Gas Recirculation (EGR. Dengan metode EGR, oksigen yang masuk ke ruang bakar akan berkurang sehingga NOX dapat diturunkan dengan signifikan, akan tetapi power dari mesin tersebut juga akan berkurang dan Particulate Matter (PM akan naik secara signifikan. Dalam penelitian ini dibahas penggunaan EGR yang telah di optimalkan dengan penambahan venturi scrubber dan cyclonic separator, tujuannya mengurangi NOX tanpa meningkatkan PM. Hasil pengujian menunjukkan NOX turun sebesar 48.89% dan PM turun dari 69,87%  menjadi 9.87%.

  5. Studi Experimental Penggunaan Venturi Scrubber Dan Cyclonic Separator Untuk Meningkatkan Kinerja Pada Sistem Exhaust Gas Recirculation (EGR) Dalam Menurunkan NOX Pada Motor Diesel

    OpenAIRE

    N, Samsu Dlukha; Ariana, I Made; Fathallah, Aguk Z. M

    2012-01-01

    Salah satu cara yang efektif untuk mengurangi NOX adalah dengan menggunakan metode Exhaust Gas Recirculation (EGR). Dengan metode EGR, oksigen yang masuk ke ruang bakar akan berkurang sehingga NOX dapat diturunkan dengan signifikan, akan tetapi power dari mesin tersebut juga akan berkurang dan Particulate Matter (PM) akan naik secara signifikan. Dalam penelitian ini dibahas penggunaan EGR yang telah di optimalkan dengan penambahan venturi scrubber dan cyclonic separator, tujuannya mengurangi ...

  6. 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...

  7. 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

  8. 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....

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

    Science.gov (United States)

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

  10. 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

  11. 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.

  12. 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 materia...

  13. 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.

  14. RECIRCULATING ACCELERATION

    International Nuclear Information System (INIS)

    BERG, J.S.; GARREN, A.A.; JOHNSTONE, C.

    2000-01-01

    This paper compares various types of recirculating accelerators, outlining the advantages and disadvantages of various approaches. The accelerators are characterized according to the types of arcs they use: whether there is a single arc for the entire recirculator or there are multiple arcs, and whether the arc(s) are isochronous or non-isochronous

  15. Experimental investigation of N2O formation in selective non-catalytic NOx reduction processes performed in stoker boiler

    Directory of Open Access Journals (Sweden)

    Krawczyk Piotr

    2016-12-01

    Full Text Available Stoker fired boiler plants are common throughout Eastern Europe. Increasingly strict emission standards will require application of secondary NOx abatement systems on such boilers. Yet operation of such systems, in addition to reducing NOx emissions, may also lead to emission of undesirable substances, for example N2O. This paper presents results of experimental tests concerning N2O formation in the selective non-catalytic NOx emission reduction process (SNCR in a stoker boiler (WR 25 type. Obtained results lead to an unambiguous conclusion that there is a dependency between the NOx and N2O concentrations in the exhaust gas when SNCR process is carried out in a coal-fired stoker boiler. Fulfilling new emission standards in the analysed equipment will require 40–50% reduction of NOx concentration. It should be expected that in such a case the N2O emission will be approximately 55–60 mg/m3, with the NOx to N2O conversion factor of about 40%.

  16. Selective Reversible Absorption of the Industrial Off-Gas Components CO2 and NOx by Ionic Liquids

    DEFF Research Database (Denmark)

    Kaas-Larsen, Peter Kjartan; Thomassen, P.; Schill, Leonhard

    2016-01-01

    Ionic liquids are promising new materials for climate and pollution control by selective absorption of CO2 and NOx in industrial off-gases. In addition practical cleaning of industrial off gases seems to be attractive by use of ionic liquids distributed on the surface of porous, high surface area...... carriers in the form of so-called Supported Ionic Liquid Phase (SILP) materials. The potential of selected ionic liquids for absorption of CO2 and NOx are demonstrated and the possible interference of other gases influencing the stability and absorption capacity of the ionic liquids are investigated...

  17. 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.

  18. Amorphous saturated Cerium-Tungsten-Titanium oxide nanofibers catalysts for NOx selective catalytic reaction

    DEFF Research Database (Denmark)

    Dankeaw, Apiwat; Gualandris, Fabrizio; Silva, Rafael Hubert

    2018-01-01

    experiments at the best working conditions (dry and in absence of SO2) are performed to characterize the intrinsic catalytic behavior of the new catalysts. At temeprature lower than 300 °C, superior NOx conversion properties of the amorphous TiOx nanofibers over the crystallized TiO2 (anatase) nanofibers......Herein for the first time, Ce0.184W0.07Ti0.748O2-δ nanofibers are prepared by electrospinning to serve as catalyst in the selective catalytic reduction (SCR) process. The addition of cerium is proven to inhibit crystallization of TiO2, yielding an amorphous TiOx-based solid solution stable up...... temperatures (catalysts in a wide range...

  19. Local Environment and Nature of Cu Active Sites in Zeolite-Based Catalysts for the Selective Catalytic Reduction of NOx

    NARCIS (Netherlands)

    Deka, U.|info:eu-repo/dai/nl/325811202; Lezcano-Gonzalez, I.; Weckhuysen, B.M.|info:eu-repo/dai/nl/285484397; Beale, A.M.|info:eu-repo/dai/nl/325802068

    2013-01-01

    Cu-exchanged zeolites have demonstrated widespread use as catalyst materials in the abatement of NOx, especially from mobile sources. Recent studies focusing on Cu-exchanged zeolites with the CHA structure have demonstrated them to be excellent catalysts in the ammonia-assisted selective catalytic

  20. Selective Reversible Absorption of the Industrial Off-Gas Components CO2 and NOx by Ionic Liquids

    DEFF Research Database (Denmark)

    Kaas-Larsen, Peter Kjartan; Thomassen, Peter; Schill, Leonard

    2016-01-01

    Ionic liquids are promising new materials for climate and pollution control by selective absorption of CO2 and NOx in industrial off-gases. In addition pratical cleaning of industrial off gases seems to be attractive by use of ionic liquids distributed on the surface of porous, high surface area...

  1. Highly selective NOx reduction for diesel engine exhaust via an electrochemical system

    DEFF Research Database (Denmark)

    Shao, Jing; Tao, Youkun; Kammer Hansen, Kent

    2016-01-01

    It is challenging to reduce the nitrogen oxides (NOx) in diesel engine exhaust due to the inhibiting effect of excess oxygen. In this study, a novel electrochemical deNOx system was developed, which eliminated the need for additional reducing materials or a sophisticated controlling system as used...

  2. Dedicated exhaust gas recirculation control systems and methods

    Science.gov (United States)

    Sczomak, David P.; Narayanaswamy, Kushal; Keating, Edward J.

    2018-05-01

    An engine control system of a vehicle includes a fuel control module that controls fuel injection of a first cylinder of an engine based on a first target air/fuel ratio that is fuel lean relative to a stoichiometric air/fuel ratio and that controls fuel injection of a second cylinder of the engine based on a second target air/fuel ratio that is fuel rich relative to stoichiometry. The first cylinder outputs exhaust to a first three way catalyst (TWC), and the second cylinder outputs exhaust to an exhaust gas recirculation (EGR) valve. An EGR control module controls opening of the EGR valve to: (i) a second TWC that reacts with nitrogen oxides (NOx) in the exhaust and outputs ammonia to a selective catalytic reduction (SCR) catalyst; and (ii) a conduit that recirculates exhaust back to an intake system of the engine.

  3. 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

  4. 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.

  5. The effects of ozonation on select waterborne steroid hormones in recirculation aquaculture systems containing sexually mature Atlantic salmon Salmo salar

    Science.gov (United States)

    A controlled 3-month study was conducted in 6 replicated water recirculation aquaculture systems (RAS) containing a mixture of sexually mature and immature Atlantic salmon Salmo salar to determine whether water ozonation is associated with a reduction in waterborne hormones. Post-smolt Atlantic salm...

  6. Electrochemical reduction of NOx

    DEFF Research Database (Denmark)

    Traulsen, Marie Lund

    NO and NO2 (collectively referred to as NOx) are air pollutants, and the largest single contributor to NOx pollution is automotive exhaust. This study investigates electrochemical deNOx, a technology which aims to remove NOx from automotive diesel exhaust by electrochemical reduction of NOx to N2...... and O2. The focus in this study is on improving the activity and selectivity of solid oxide electrodes for electrochemical deNOx by addition of NOx storage compounds to the electrodes. Two different composite electrodes, La0.85Sr0.15MnO3-δ-Ce0.9Gd0.1O1.95 (LSM15-CGO10) and La0.85Sr0.15FeO3-δ-Ce0.9Gd0.1O......1.95 (LSF15-CGO10), have been investigated in combination with three different NOx storage compounds: BaO, K2O and MnOx. The main focus in the investigation has been on conversion measurements and electrochemical characterization, the latter by means of electrochemical impedance spectroscopy...

  7. Control-oriented modeling of two-stroke diesel engines with exhaust gas recirculation for marine applications

    OpenAIRE

    Llamas, Xavier; Eriksson, Lars

    2018-01-01

    Large marine two-stroke diesel engines are widely used as propulsion systems for shipping worldwide and are facing stricter NOx emission limits. Exhaust gas recirculation is introduced to these engines to reduce the produced combustion NOx to the allowed levels. Since the current number of engines built with exhaust gas recirculation is low and engine testing is very expensive, a powerful alternative for developing exhaust gas recirculation controllers for such engines is to use control-orien...

  8. Effect of process parameters and injector position on the efficiency of NOx reduction by selective non catalytic reduction technique

    International Nuclear Information System (INIS)

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

    2009-01-01

    An experimental investigation has been performed to study the effect of atomizer pressure dilution of the reducing reagent and the injector position on the efficiency or the NOx reduction by a selective non-catalytic reduction technique using urea as a reducing agent. Experiments were performed with a flow reactor in which flue gas was generated by the combustion of methane in air at stoichiometric amount of oxygen and the desired levels of initial NOx (400-450 ppm) were achieved by doping the flame with ammonia. The work was directed to investigate the effect of atomizer pressure, dilution of urea reagent and the injector position. The atomizer pressure was varied from 1 to 3bar and 20-25% increase in efficiency was observed by decreasing the pressure. Effect of dilution of urea solution was investigated by varying the strength of the solution from the 8 to 32% and 40-45% increase in the efficiency was observed. Effects of injector position was investigated by injecting the urea solution both in co current and counter current direction of the flue gases and 20-25% increase in the efficiency was observed in counter current direction. (author)

  9. The selective reduction of NO@#x@# with NH@#3@# over zirconia-supported vanadia catalysts

    NARCIS (Netherlands)

    Szakacs, S.; Altena, G.J.; Altena, G.J.; Fransen, T.; van Ommen, J.G.; Ross, J.R.H.; Ross, J.R.H.

    1993-01-01

    A series of sub-monolayer vanadia-on-zirconia catalysts have been prepared and the activities of these have been measured for the selective reduction of NO with NH3. It has been found that the activity per vanadium surface species depends on the square of the vanadium surface coverage. We therefore

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

    Science.gov (United States)

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

    2013-01-01

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

  11. Combustion, performance, and selective catalytic reduction of NOx for a diesel engine operated with combined tri fuel (H_2, CH_4, and conventional diesel)

    International Nuclear Information System (INIS)

    Abu-Jrai, Ahmad M.; Al-Muhtaseb, Ala'a H.; Hasan, Ahmad O.

    2017-01-01

    In this study, the effect of tri fuel (ULSD, H_2, and CH_4) operation under real exhaust gas conditions with different gaseous fuel compositions on the combustion characteristics, engine emissions, and selective catalytic reduction (SCR) after treatment was examined at low, medium, and high engine loads. Pt/Al_2O_3-SCR reactor was used and operated at different exhaust gas temperatures. Results revealed that at low load, the two gaseous fuels (H_2 and CH_4) have the same trend on combustion proccess, where both reduce the in-cylinder pressure and rate of heat release. At the high engine load there was a considerable influence appeared as an increase of the premixed combustion phase and a significant decrease of the total combustion duration. In terms of emissions, it was observed that at high engine load, fuels with high CH_4 content tend to reduce NOx formation, whereas, fuels with high H_2 content tend to reduce PM formation, moreover, combustion of tri fuel with 50:50 fuel mixture resulted in lower BSFC compared to the other ratios and hence, the best engine efficiency. The hydrocarbon-SCR catalyst has shown satisfactory performance in NOx reduction under real diesel exhaust gas in a temperature window of 180–280 °C for all engine loads. - Highlights: • Effect of tri fuel (ULSD, H_2, CH_4) on combustion and engine emissions was examined. • Fuel with high CH_4 content (H50-M50 and H25-M75) tend to reduce NOx formation. • Fuel with high H_2 content (H75-M25 and H50-M50) tend to reduce PM formation. • Increasing the percentage of H_2 in the feed gas improved the NO_x reduction. • The hydrocarbon-SCR catalyst has shown satisfactory performance in NO_x reduction.

  12. Selective catalytic reduction (SCR) NOx control for small natural gas-fired prime movers

    International Nuclear Information System (INIS)

    Shareef, G.S.; Stone, D.K.; Ferry, K.R.; Johnson, K.L.; Locke, K.S.

    1992-01-01

    The application of selective catalytic reduction (SCR) to small natural gas-fired prime movers at cogeneration facilities and compressor stations could possibly increase due to regulatory forces to limit NO x from such sources. The natural gas industry is presently without a current database with which to evaluate the cost and operating characteristics of SCR under the conditions anticipated for small prime movers. This paper presents the results from a two-phase study undertaken to document SCR applications with emphasis on SCR system performance and costs. The database of small natural gas-fired prime mover SCR experience, focusing on prime mover characterization, SCR system performance, and SCR system costs will be described. Result from analysis of performance and cost data will be discussed, including analytical tools developed to project SCR system performance and costs

  13. Multi-stage selective catalytic reduction of NOx in lean burn engine exhaust

    Energy Technology Data Exchange (ETDEWEB)

    Penetrante, B.M.; Hsaio, M.C.; Merritt, B.T.; Vogtlin, G.E. [Lawrence Livermore National Lab., CA (United States)

    1997-12-31

    Many studies suggest that the conversion of NO to NO{sub 2} is an important intermediate step in the selective catalytic reduction (SCR) of NO{sub x} to N{sub 2}. Some effort has been devoted to separating the oxidative and reductive functions of the catalyst in a multi-stage system. This method works fine for systems that require hydrocarbon addition. The hydrocarbon has to be injected between the NO oxidation catalyst and the NO{sub 2} reduction catalyst; otherwise, the first-stage oxidation catalyst will also oxidize the hydrocarbon and decrease its effectiveness as a reductant. The multi-stage catalytic scheme is appropriate for diesel engine exhausts since they contain insufficient hydrocarbons for SCR, and the hydrocarbons can be added at the desired location. For lean-burn gasoline engine exhausts, the hydrocarbons already present in the exhausts will make it necessary to find an oxidation catalyst that can oxidize NO to NO{sub 2} but not oxidize the hydrocarbon. A plasma can also be used to oxidize NO to NO{sub 2}. Plasma oxidation has several advantages over catalytic oxidation. Plasma-assisted catalysis can work well for both diesel engine and lean-burn gasoline engine exhausts. This is because the plasma can oxidize NO in the presence of hydrocarbons without degrading the effectiveness of the hydrocarbon as a reductant for SCR. In the plasma, the hydrocarbon enhances the oxidation of NO, minimizes the electrical energy requirement, and prevents the oxidation of SO{sub 2}. This paper discusses the use of multi-stage systems for selective catalytic reduction of NO{sub x}. The multi-stage catalytic scheme is compared to the plasma-assisted catalytic scheme.

  14. NOx formation and selective non-catalytic reduction (SNCR) in a fluidized bed combustor of biomass

    International Nuclear Information System (INIS)

    Mahmoudi, Shiva; Baeyens, Jan; Seville, Jonathan P.K.

    2010-01-01

    Caledonian Paper (CaPa) is a major paper mill, located in Ayr, Scotland. For its steam supply, it previously relied on the use of a Circulating Fluidized Bed Combustor (CFBC) of 58 MW th , burning coal, wood bark and wastewater treatment sludge. It currently uses a bubbling fluidized bed combustor (BFBC) of 102 MW th to generate steam at 99 bar, superheated to 465 o C. The boiler is followed by steam turbines and a 15 kg/s steam circuit into the mill. Whereas previously coal, wood bark and wastewater treatment sludge were used as fuel, currently only plantation wood (mainly spruce), demolition wood, wood bark and sludge are used. Since these biosolids contain nitrogen, fuel NO x is formed at the combustion temperature of 850-900 o C. NO x emissions (NO + NO 2 ) vary on average between 300 and 600 mg/Nm 3 (dry gas). The current emission standard is 350 mg/Nm 3 but will be reduced in the future to a maximum of 233 mg/Nm 3 for stand-alone biomass combustors of capacity between 50 and 300 MW th according to the EU LCP standards. NO x abatement is therefore necessary. In the present paper we firstly review the NO x formation mechanisms, proving that for applications of fluidized bed combustion, fuel NO x is the main consideration, and the contribution of thermal NO x to the emissions insignificant. We then assess the deNO x techniques presented in the literature, with an updated review and special focus upon the techniques that are applicable at CaPa. From these techniques, Selective Non-catalytic Reduction (SNCR) using ammonia or urea emerges as the most appropriate NO x abatement solution. Although SNCR deNO x is a selective reduction, the reactions of NO x reduction by NH 3 in the presence of oxygen, and the oxidation of NH 3 proceed competitively. Both reactions were therefore studied in a lab-scale reactor and the results were transformed into design equations starting from the respective reaction kinetics. An overall deNO x yield can then be predicted for any

  15. Enhanced Activity of Nanocrystalline Zeolites for Selective Catalytic Reduction of NOx

    International Nuclear Information System (INIS)

    Sarah C. Larson; Vicki H. Grassian

    2006-01-01

    Nanocrystalline zeolites with discrete crystal sizes of less than 100 nm have different properties relative to zeolites with larger crystal sizes. Nanocrystalline zeolites have improved mass transfer properties and very large internal and external surface areas that can be exploited for many different applications. The additional external surface active sites and the improved mass transfer properties of nanocrystalline zeolites offer significant advantages for selective catalytic reduction (SCR) catalysis with ammonia as a reductant in coal-fired power plants relative to current zeolite based SCR catalysts. Nanocrystalline NaY was synthesized with a crystal size of 15-20 nm and was thoroughly characterized using x-ray diffraction, electron paramagnetic resonance spectroscopy, nitrogen adsorption isotherms and Fourier Transform Infrared (FT-IR) spectroscopy. Copper ions were exchanged into nanocrystalline NaY to increase the catalytic activity. The reactions of nitrogen dioxides (NO x ) and ammonia (NH 3 ) on nanocrystalline NaY and CuY were investigated using FT-IR spectroscopy. Significant conversion of NO 2 was observed at room temperature in the presence of NH 3 as monitored by FT-IR spectroscopy. Copper-exchanged nanocrystalline NaY was more active for NO 2 reduction with NH 3 relative to nanocrystalline NaY

  16. Selection of best impregnated palm shell activated carbon (PSAC) for simultaneous removal of SO2 and NOx

    International Nuclear Information System (INIS)

    Sumathi, S.; Bhatia, S.; Lee, K.T.; Mohamed, A.R.

    2010-01-01

    This work examines the impregnated carbon-based sorbents for simultaneous removal of SO 2 and NOx from simulated flue gas. The carbon-based sorbents were prepared using palm shell activated carbon (PSAC) impregnated with several metal oxides (Ni, V, Fe and Ce). The removal of SO 2 and NOx from the simulated flue gas was investigated in a fixed-bed reactor. The results showed that PSAC impregnated with CeO 2 (PSAC-Ce) reported the highest sorption capacity among other impregnated metal oxides for the simultaneous removal of SO 2 and NOx. PSAC-Ce showed the longest breakthrough time of 165 and 115 min for SO 2 and NOx, respectively. The properties of the pure and impregnated PSAC were analyzed by BET, FTIR and XRF. The physical-chemical features of the PSAC-Ce sorbent indicated a catalytic activity in both the sorption of SO 2 and NOx. The formation of both sulfate (SO 4 2- ) and nitrate (NO 3- ) species on spent PSAC-Ce further prove the catalytic role played by CeO 2 .

  17. Selection of best impregnated palm shell activated carbon (PSAC) for simultaneous removal of SO{sub 2} and NOx

    Energy Technology Data Exchange (ETDEWEB)

    Sumathi, S.; Bhatia, S.; Lee, K.T. [School of Chemical Engineering, Engineering Campus, Universiti Sains Malaysia, Seri Ampangan, 14300 Nibong Tebal, Pulau Pinang (Malaysia); Mohamed, A.R., E-mail: chrahman@eng.usm.my [School of Chemical Engineering, Engineering Campus, Universiti Sains Malaysia, Seri Ampangan, 14300 Nibong Tebal, Pulau Pinang (Malaysia)

    2010-04-15

    This work examines the impregnated carbon-based sorbents for simultaneous removal of SO{sub 2} and NOx from simulated flue gas. The carbon-based sorbents were prepared using palm shell activated carbon (PSAC) impregnated with several metal oxides (Ni, V, Fe and Ce). The removal of SO{sub 2} and NOx from the simulated flue gas was investigated in a fixed-bed reactor. The results showed that PSAC impregnated with CeO{sub 2} (PSAC-Ce) reported the highest sorption capacity among other impregnated metal oxides for the simultaneous removal of SO{sub 2} and NOx. PSAC-Ce showed the longest breakthrough time of 165 and 115 min for SO{sub 2} and NOx, respectively. The properties of the pure and impregnated PSAC were analyzed by BET, FTIR and XRF. The physical-chemical features of the PSAC-Ce sorbent indicated a catalytic activity in both the sorption of SO{sub 2} and NOx. The formation of both sulfate (SO{sub 4}{sup 2-}) and nitrate (NO{sup 3-}) species on spent PSAC-Ce further prove the catalytic role played by CeO{sub 2}.

  18. 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.

  19. Dust deposit in recirculation regions

    International Nuclear Information System (INIS)

    Griemert, R.

    1985-03-01

    The present report shows investigations, which have been carried out in a closed duct at forward and backward facing steps. Distribution of fluid velocity and fluid fluctuations in and normal to main flow direction as well as the distribution of Reynolds shear stress have been measured. The mass transfer downstream of a backward facing step has been investigated as well. By using graphite-, copper-, tin- and rubber dust, conditions of deposition have been defined experimentally. A serie of photos shows the filling of a recirculation region downstream of a backward facing step with graphite dust. The present investigations allow to avoid deposition of dust in recirculation regions by selecting the fluid numbers in an appropriate way. (orig.) [de

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

    Science.gov (United States)

    Sobolevskiy, Anatoly [Orlando, FL; Rossin, Joseph A [Columbus, OH; Knapke, Michael J [Columbus, OH

    2011-07-12

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

  1. 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.

  2. 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

  3. Environmental control implications of generating electric power from coal. 1977 technology status report. Appendix D. Assessment of NO/sub x/ control technology for coal fired utility boilers. [Low-excess-air, staged combustion, flu gas recirculation and burner design

    Energy Technology Data Exchange (ETDEWEB)

    1977-12-01

    An NOx control technology assessment study was conducted to examine the effectiveness of low-excess-air firing, staged combustion, flue gas recirculation, and current burner/boiler designs as applied to coal-fired utility boilers. Significant variations in NOx emissions exist with boiler type, firing method, and coal type, but a relative comparison of emissions control performance, cost, and operational considerations is presented for each method. The study emphasized the numerous operational factors that are of major importance to the user in selecting and implementing a combustion modification technique. Staged combustion and low-excess-air operation were identified as the most cost-effective methods for existing units. Close control of local air/fuel ratios and rigorous combustion equipment maintenance are essential to the success of both methods. Flue gas recirculation is relatively ineffective and has the added concern of tube erosion. More research is needed to resolve potential corrosion concerns with low-NOx operating modes. Low-NOx burners in conjunction with a compartmentalized windbox are capable of meeting a 0.6-lb/million Btu emission level on new units. Advanced burner designs are being developed to meet research emission goals of approximately 0.25 lb/MBtu.

  4. Treatment of vinasses - recirculation

    Directory of Open Access Journals (Sweden)

    Germán Andrés Castro Moreno

    2009-08-01

    Full Text Available The purpose of this minireview is to give an overview of treatments that have been applied on the vinasse, residue from the alcoholic fermentation; appoint some of its advantages and disadvantages, and then submit recirculation, as one of the best options from an economic point of view and easy implementation, for those who are not interested in the ethanol byproducts.

  5. Study of Water Quality of Recirculated Water in Aquaponic Systems: Study of speciation of selected metals and characterization of the properties of natural organic matter

    OpenAIRE

    Gjesteland, Ingrid

    2013-01-01

    This thesis describes an extensive study on how water quality changes over time in a small scale recirculating system where waste water from smolt production was used to grow lettuce for commercial use. The treatment effect of lettuce on different solutions was tested and corresponding lettuce yield was evaluated. In order to enhance the treatment effect a rock wool filter was used on certain solutions. Important water quality parameters were measured every day, and the element concentration ...

  6. 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.

  7. Exhaust Gas Recirculation Control for Large Diesel Engines - Achievable Performance with SISO Design

    DEFF Research Database (Denmark)

    Hansen, Jakob Mahler; Blanke, Mogens; Niemann, Hans Henrik

    2013-01-01

    This paper investigates control possibilities for Exhaust Gas Recirculation (EGR) on large diesel engines. The goal is to reduce the amount of NOx in the exhaust gas by reducing the oxygen concentration available for combustion. Control limitations imposed by the system are assessed using linear...

  8. High ratio recirculating gas compressor

    Science.gov (United States)

    Weinbrecht, J.F.

    1989-08-22

    A high ratio positive displacement recirculating rotary compressor is disclosed. The compressor includes an integral heat exchanger and recirculation conduits for returning cooled, high pressure discharge gas to the compressor housing to reducing heating of the compressor and enable higher pressure ratios to be sustained. The compressor features a recirculation system which results in continuous and uninterrupted flow of recirculation gas to the compressor with no direct leakage to either the discharge port or the intake port of the compressor, resulting in a capability of higher sustained pressure ratios without overheating of the compressor. 10 figs.

  9. Selective catalytic reduction of NOx and N{sub 2}O by NH{sub 3} over Fe-FER; Developpement d'un traitement catalytique combine des NOx et de N{sub 2}O par NH{sub 3} sur Fe-Fer

    Energy Technology Data Exchange (ETDEWEB)

    Kieger, St. [Grande Paroisse, 76 - Grand-Quevilly (France); Navascues, L.; Gry, Ph. [Grande Paroisse, 92 - Paris la Defense (France)

    2001-07-01

    The emission of nitrogen oxides from anthropogenic activities is a major environmental issue. N{sub 2}O is taking part to the global warming and depletion of the stratospheric ozone layer, and NOx to acid rains. At the Kyoto Conference in 1997, the European Union committed itself to reduce by 8% the release of greenhouse gases at the horizon 2010. The selective catalytic reduction (SCR) of NOx by NH{sub 3} is nowadays the main control technology for the emissions from nitric acid plant. Therefore, Grande Paroisse and IRMA have developed a new catalyst (Fe-FER) for the SCR of N{sub 2}O by NH{sub 3}. The catalyst was evaluated in a pilot plant and in the same operating conditions than a DeNOx catalyst. At a space velocity of 9000 to 12000 h{sup -1}, a decomposition of 50% of N{sub 2}O was achieved at 440 deg C. Moreover for the same decomposition level, the temperature could be shifted to 390 deg C by adding ammonia, and the complete reduction of NOx was also observed. This new catalyst is rather bi-functional. Also after months of using, the catalyst did not show major loss of activity nor mechanical strength. (authors)

  10. Thermophysical fundamentals of cyclonic recirculating heating devices

    Science.gov (United States)

    Karpov, S. V.; Zagoskin, A. A.

    2017-10-01

    This report presents the results of experimental and theoretical research of aerodynamics and convective heat transfer in cyclone devices with the new system of external recirculation of heating gas under the influence of radial pressure gradient in a heat carrier’s swirling turbulent flow. The dynamic problem of tangential velocity distribution in a clearance volume is solved at various re-circulation ratio values including limiting quantities (kr = 0; 1) and variations in cyclonic combustion chamber’s design parameters and operating conditions (Rer); the integrated calculation ratios for fundamental aerodynamic characteristics of a recirculation device are derived. The first experimental and numerical studies of convective heat transfer on internal and external surfaces of a hollow shaft in a swirling recirculation flow are derived through the instrumentality of OpenFOAM, these studies are also conducted for a setting of several cylindrical solid inserts. The external surface heat problem of a hollow cylindrical insert is solved with integral and digital methods; generalized similarity equations for the internal and external surfaces extended in range of Reynolds number are derived. The experimental data is in reasonable agreement with the derived curves and the results of mathematic modelling of convective heat transfer. Calculation recommendations for optimal selection of kr values at various ratios of their geometric characteristics and products utilization rate are obtained.

  11. 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...

  12. Recirculation system for nuclear reactors

    International Nuclear Information System (INIS)

    Braun, H. E.; Dollard, W. J.; Tower, S. N.

    1980-01-01

    A recirculation system for use in pressurized water nuclear reactors to increase the output temperature of the reactor coolant, thereby achieving a significant improvement in plant efficiency without exceeding current core design limits. A portion of the hot outlet coolant is recirculated to the inlets of the peripheral fuel assemblies which operate at relatively low power levels. The outlet temperature from these peripheral fuel assemblies is increased to a temperature above that of the average core outlet. The recirculation system uses external pumps and introduces the hot recirculation coolant to the free space between the core barrel and the core baffle, where it flows downward and inward to the inlets of the peripheral fuel assemblies. In the unlikely event of a loss of coolant accident, the recirculation system flow path through the free space and to the inlets of the fuel assemblies is utilized for the injection of emergency coolant to the lower vessel and core. During emergency coolant injection, the emergency coolant is prevented from bypassing the core through the recirculation system by check valves inserted into the recirculation system piping

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

    International Nuclear Information System (INIS)

    Oh, Kwang Seok; Woo, Seong Ihl

    2011-01-01

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

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

    Science.gov (United States)

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

    2016-01-15

    The development of catalysts for selective catalytic reduction (SCR) reactions that are highly active at low temperatures and show good resistance to SO2 and H2O 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-CeO2/MIL-100(Fe) catalyst shows improved catalytic activity both at low temperatures and throughout a wide temperature window. The temperature window for 90% NOx 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 NO2 species responsible for fast SCR reactions. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. Alternative deNOx catalysts and technologies

    DEFF Research Database (Denmark)

    Due-Hansen, Johannes

    The present thesis entitled Alternative deNOx Catalysts and technologies revolves around the topic of removal of nitrogen oxides. Nitrogen oxides, NOx, are unwanted byproducts formed during combustion (e.g. in engines or power plants). If emitted to the atmosphere, they are involved...... in the formation of acid rain and photochemical smog. Some basic concepts and reactions regarding the formation and removal of NOx are presented in chapter 1 and 2. Two approaches are undertaken in the present work to reduce the emission of NOx: by means of catalytic removal, and by NO absorption in ionic liquids....... 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...

  16. Program to reduce NOx emissions of HNO{sub 3} plants with selective catalytic reduction; Programme visant a reduire les emissions de NOx d'ateliers d'HNO{sub 3} par reduction catalytique selective

    Energy Technology Data Exchange (ETDEWEB)

    Gry, Ph. [Grande Paroisse SA, Group ATOFINA, 92 - Paris la Defense (France)

    2001-07-01

    Grande Paroisse well known as G.P. has been created in 1919. Nowadays, it is an affiliated company of ATOFINA. The Company is the first French producer of fertilizers and the third West European. In its sites G.P. controls 1.3 millions metric tons per year of nitric acid, on 13 units. Continuous improvement of its technology together with productivity development make G.P. one of the most competitive fertilizer manufacturer. A technical team achieves this objective and maintains a world wide reputable technology. For the past 15 years, industry has tried to reduce NO{sub x} atmospheric pollution. The SCR (Selective Catalytic Reduction) is most used with ammonia for nitric acid units and described here under. (author)

  17. Re-circulating linac vacuum system

    International Nuclear Information System (INIS)

    Wells, Russell P.; Corlett, John N.; Zholents, Alexander A.

    2003-01-01

    The vacuum system for a proposed 2.5 GeV, 10ΜA recirculating linac synchrotron light source [1] is readily achievable with conventional vacuum hardware and established fabrication processes. Some of the difficult technical challenges associated with synchrotron light source storage rings are sidestepped by the relatively low beam current and short beam lifetime requirements of a re-circulating linac. This minimal lifetime requirement leads directly to relatively high limits on the background gas pressure through much of the facility. The 10ΜA average beam current produces very little synchrotron radiation induced gas desorption and thus the need for an ante-chamber in the vacuum chamber is eliminated. In the arc bend magnets, and the insertion devices, the vacuum chamber dimensions can be selected to balance the coherent synchrotron radiation and resistive wall wakefield effects, while maintaining the modest limits on the gas pressure and minimal outgassing

  18. Study on performance and emission characteristics of a single cylinder diesel engine using exhaust gas recirculation

    Directory of Open Access Journals (Sweden)

    Anantha Raman Lakshmipathi

    2017-01-01

    Full Text Available Exhaust gas re-circulation is a method used in compression ignition engines to control and reduce NOx emission. These emissions are controlled by reducing the oxygen concentration inside the cylinder and thereby reducing the flame temperature of the charge mixture inside the combustion chamber. In the present investigation, experiments were performed to study the effect of exhaust gas re-circulation on performance and emission characteristics in a four stroke single cylinder, water cooled and constant speed diesel engine. The experiments were performed to study the performance and emissions for different exhaust gas re-circulation ratios of the engine. Performance parameters such as brake thermal efficiency, indicated thermal efficiency, specific fuel consumption, total fuel consumption and emission parameters such as oxides of nitrogen, unburned hydrocarbons, carbon monoxide, carbon dioxide and smoke opacity were measured. Reductions in NOx and CO2 were observed but other emissions like HC, CO, and smoke opacity were found to have increased with the usage of exhaust gas re-circulation. The 15% exhaust gas re-circulation was found optimum for the engine in the aspects of performance and emission.

  19. 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.

  20. Closed recirculation-Water treatment

    International Nuclear Information System (INIS)

    Hamza, Hamza B.; Ben Ali, Salah; Saad, Mohamed A.; Traish, Massud R.

    2005-01-01

    This water treatment is a practical work applied in the center, for a closed recirculation-water system. The system had experienced a serious corrosion problem, due to the use of inadequate water. This work includes chemical preparation for the system. Water treatment, special additives, and follow-up, which resulted in the stability of the case. This work can be applied specially for closed recirculation warm, normal, and chilled water. (author)

  1. The influence of a silica pillar in lamellar tetratitanate for selective catalytic reduction of NOx using NH3

    International Nuclear Information System (INIS)

    Nogueira da Cunha, Beatriz; Gonçalves, Alécia Maria; Gomes da Silveira, Rafael; Urquieta-González, Ernesto A.; Magalhães Nunes, Liliane

    2015-01-01

    Highlights: • Potassium ions significantly affected the SCR. • The introduction of silica in the catalyst promotes the NH 3 -SCR reaction. • The catalysts activities were not significantly influenced by SO 2 addition. - Abstract: Silica-pillared layered titanate (SiO 2 –Ti 4 O 9 ) was prepared by intercalating organosilanes into the interlayers of a layered K 2 Ti 4 O 9 followed by calcination at 500 °C. The lamellar titanates produced were used as a support to prepare vanadium catalysts (1 and 2 wt%) through wet impregnation for selective catalytic reduction (SCR) of NO. The catalysts were characterized using nitrogen adsorption (BET), X-ray diffraction (XRD), temperature programmed reduction (H 2 -TPR), nuclear magnetic resonance ( 29 Si NMR), and infrared spectroscopy (FT-IR). Reduction of NO by NH 3 was studied in a fixed-bed reactor packed with the catalysts and fed a mixture comprising 1% NH 3 , 1% NO, 10% O 2 , and 34 ppm SO 2 (when used) in helium. The results demonstrate that activity is correlated with the support, i.e., with acidic strength of catalysts. The potassium in the support, K 2 Ti 4 O 9 , significantly affected the reaction and level of vanadium species reduction. The catalyst (1VSiT) with 1 wt% vanadium impregnated on the SiO 2 –Ti 4 O 9 support reduced ∼80% of the NO. Approximately the same conversion rate was generated on the catalyst (2VSiT) with 2 wt% vanadium using the same support. The increased NH 3 adsorption demonstrate that introduction of silica in the catalyst promotes the NH 3 -SCR reaction. More importantly, 2VSiT and 1VSiT were strongly resistant to SO 2 poisoning

  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. 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

  4. Implementation of Exhaust Gas Recirculation for Double Stage Waste Heat Recovery System on Large Container Vessel

    DEFF Research Database (Denmark)

    Andreasen, Morten; Marissal, Matthieu; Sørensen, Kim

    2014-01-01

    Concerned to push ships to have a lower impact on the environment, the International Maritime Organization are implementing stricter regulation of NOx and SOx emissions, called Tier III, within emission control areas (ECAs). Waste Heat Recovery Systems (WHRS) on container ships consist...... of recovering some of the waste heat from the exhaust gas. This heat is converted into electrical energy used on-board instead of using auxiliary engines. Exhaust Gas Recirculation (EGR) systems, are recirculating a part of the exhaust gas through the engine combustion chamber to reduce emissions. WHRS combined...... with EGR is a potential way to improve system efficiency while reducing emissions. This paper investigates the feasibility of combining the two systems. EGR dilutes the fuel, lowering the combustion temperature and thereby the formation of NOx, to reach Tier III limitation. A double stage WHRS is set up...

  5. 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

  6. Simultaneously reducing CO2 and particulate exposures via fractional recirculation of vehicle cabin air.

    Science.gov (United States)

    Jung, Heejung S; Grady, Michael L; Victoroff, Tristan; Miller, Arthur L

    2017-07-01

    Prior studies demonstrate that air recirculation can reduce exposure to nanoparticles in vehicle cabins. However when people occupy confined spaces, air recirculation can lead to carbon dioxide (CO 2 ) accumulation which can potentially lead to deleterious effects on cognitive function. This study proposes a fractional air recirculation system for reducing nanoparticle concentration while simultaneously suppressing CO 2 levels in the cabin. Several recirculation scenarios were tested using a custom-programmed HVAC (heat, ventilation, air conditioning) unit that varied the recirculation door angle in the test vehicle. Operating the recirculation system with a standard cabin filter reduced particle concentrations to 1000 particles/cm 3 , although CO 2 levels rose to 3000 ppm. When as little as 25% fresh air was introduced (75% recirculation), CO 2 levels dropped to 1000 ppm, while particle concentrations remained below 5000 particles/cm 3 . We found that nanoparticles were removed selectively during recirculation and demonstrated the trade-off between cabin CO 2 concentration and cabin particle concentration using fractional air recirculation. Data showed significant increases in CO 2 levels during 100% recirculation. For various fan speeds, recirculation fractions of 50-75% maintained lower CO 2 levels in the cabin, while still reducing particulate levels. We recommend fractional recirculation as a simple method to reduce occupants' exposures to particulate matter and CO 2 in vehicles. A design with several fractional recirculation settings could allow air exchange adequate for reducing both particulate and CO 2 exposures. Developing this technology could lead to reductions in airborne nanoparticle exposure, while also mitigating safety risks from CO 2 accumulation.

  7. Modelling for Control of Exhaust Gas Recirculation on Large Diesel Engines

    DEFF Research Database (Denmark)

    Hansen, Jakob Mahler; Zander, Claes-Göran; Pedersen, Nicolai

    2013-01-01

    Exhaust Gas Recirculation (EGR) reduces NOx emissions by reducing O2 concentration for the combustion and is a preferred way to obtain emission regulations that will take effect from 2016. If not properly controlled, reduction of O2 has adverse side eects and proper control requires proper dynami...... principles followed by parameter identication and compares the results of these approaches. The paper performs a validation against experimental data from a test engine and presents a linearised model for EGR control design....

  8. Novel p47phox-related organizers regulate NADPH oxidase 1 (Nox1) activity and localization

    Science.gov (United States)

    Gianni, Davide; Diaz, Begoña; Taulet, Nicolas; Fowler, Bruce; Courtneidge, Sara A.; Bokoch, Gary M.

    2010-01-01

    The mechanisms that determine localized formation of reactive oxygen species (ROS) via NADPH oxidases (Nox) in nonphagocytic cells are unknown. We show that the c-Src substrate proteins Tks4 and Tks5 are functional members of a p47phox-related organizer superfamily. Tks proteins selectively support Nox1 and Nox3 (vs. Nox2 and Nox4) activity in reconstituted cellular systems, and interact with the NoxA1 activator protein through an SH3-mediated interaction. Endogenous Tks4 is required for Rac GTPase-dependent ROS production by DLD1 colon cancer cells. Tks4 recruits Nox1 to invadopodia that form in DLD1 cells in a Tks- and Nox-dependent fashion. We propose that Tks organizers represent novel members of an organizer superfamily that link Nox to localized ROS formation. PMID:19755710

  9. Recirculation nursery systems for bivalves

    NARCIS (Netherlands)

    Kamermans, P.; Blanco Garcia, A.; Joaquim, Sandra; Matias, Domitilia; Magnesen, Thorolf; Nicolas, J.; Petten, Bruno; Robert, Rene

    2016-01-01

    n order to increase production of bivalves in hatcheries and nurseries, the development of new technology and its integration into commercial bivalve hatcheries is important. Recirculation aquaculture systems (RASs) have several advantages: high densities of the species can be cultured resulting in

  10. Recirculating induction accelerators for heavy ion fusion

    International Nuclear Information System (INIS)

    Barnard, J.J.; Deadrick, F.; Bangerter, R.O.

    1993-01-01

    We have recently completed a two-year study of recirculating induction heavy-ion accelerators (recirculators) as low-cost drivers for inertial-fusion-energy power plants. We present here a summary of that study and other recent work on recirculators

  11. Hybrid preheat/recirculating steam generator

    International Nuclear Information System (INIS)

    Lilly, G.P.

    1985-01-01

    The patent describes a hybrid preheat/recirculating steam generator for nuclear power plants. The steam generator utilizes recirculated liquid to preheat incoming liquid. In addition, the steam generator incorporates a divider so as to limit the amount of recirculating water mixed with the feedwater. (U.K.)

  12. 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

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

    Energy Technology Data Exchange (ETDEWEB)

    Jerry B. Urbas

    1999-05-01

    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

  14. DOGBONE GEOMETRY FOR RECIRCULATING ACCELERATORS

    International Nuclear Information System (INIS)

    BERG, J.S.; JOHNSTONE, C.; SUMMERS, D.

    2001-01-01

    Most scenarios for accelerating muons require recirculating acceleration. A racetrack shape for the accelerator requires particles with lower energy in early passes to traverse almost the same length of arc as particles with the highest energy. This extra arc length may lead to excess decays and excess cost. Changing the geometry to a dogbone shape, where there is a single linac and the beam turns completely around at the end of the linac, returning to the same end of the linac from which it exited, addresses this problem. In this design, the arc lengths can be proportional to the particle's momentum. This paper proposes an approximate cost model for a recirculating accelerator, attempts to make cost-optimized designs for both racetrack and dogbone geometries, and demonstrates that the dogbone geometry does appear to be more cost effective

  15. The impact of particulate matter (PM and nitric oxides (NOx on human health and an analysis of selected sources accounting for their emission in Poland

    Directory of Open Access Journals (Sweden)

    Jakub Krzeszowiak

    2016-10-01

    Full Text Available Introduction and objective: This paper is concerned with the harmful impact of nitric oxides (NOx and particulate matter (PM on humans. The objective was to determine which source of emission is the most urgent in terms of its reduction.Abbreviated description of the state of knowledge: In published epidemiological studies multiple notifications indicating the harmful impact of particulate matter on human health can be found. The harmful impact is underscored by the increase in the number of hospitalisations owing to diseases of respiratory and cardio-vascular systems, as well as by the rise in general fatality rate. The analysis of the PM impact on the human body is prompted by the fact that its detrimental effects are not clearly defined. Additionally, nitric oxides contribute to the increased number of exacerbations of respiratory disease and are a factor increasing susceptibility to development of local inflammation. Conclusions: The following study is meant to show that the air pollution which derives from vehicles (NOx and PM has a significant impact on human health. This applies particularly to residents of cities and big towns. This issue has gained special importance in Poland. According to the data from the Central Statistical Office, the increasing number of vehicles in use and their age lead to increased emission of the pollutants considered.

  16. 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...

  17. Emission characteristics of iso-propanol/gasoline blends in a spark-ignition engine combined with exhaust gas re-circulation

    Directory of Open Access Journals (Sweden)

    Gong Jing

    2014-01-01

    Full Text Available Experiments were carried out in a spark-ignition engine fueled with iso-propanol/gasoline blends. Emission characteristics of this engine were investigated experimentally, including gaseous emissions (HC, CO, NOx and particulate matter emission in term of number and size distributions. The effects of different iso-propanol percentages, loads and exhaust gas recirculation rates on emissions were analyzed. Results show that the introduction of exhaust gas recirculation reduces the NOx emission and NOx emission gives the highest value at full load condition. HC and CO emissions present inconspicuous variations at all the loads except the load of 10%. Additionally, HC emission shows a sharp increase for pure propanol when the exhaust gas recirculation rate is up to 5%, while little variation is observed at lager exhaust gas recirculation rates. Moreover, the particulate matter number concentration increases monotonically with the increase of load and the decrease of exhaust gas recirculation rate. There exists a critical spark timing that produces the highest particulate matter number concentration at all the blending ratios.

  18. Fractal solutions of recirculation tubular chemical reactors

    International Nuclear Information System (INIS)

    Berezowski, Marek

    2003-01-01

    Three kinds of fractal solutions of model of recirculation non-adiabatic tubular chemical reactors are presented. The first kind concerns the structure of Feigenbaum's diagram on the limit of chaos. The second kind and the third one concern the effect of initial conditions on the dynamic solutions of models. In the course of computations two types of recirculation were considered, viz. the recirculation of mass (return of a part of products' stream) and recirculation of heat (heat exchange in the external heat exchanger)

  19. Spatiotemporal distribution of NOx storage and impact on NH3 and N2O selectivities during lean/rich cycling of a Ba-based lean NOx trap catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Jae-Soon [ORNL; Partridge Jr, William P [ORNL; Pihl, Josh A [ORNL; Kim, Miyoung [ORNL; Koci, Petr [Institute of Chemical Technology, Prague, Czech Republic; Daw, C Stuart [ORNL

    2012-01-01

    We summarize results from an investigation of the spatiotemporal distribution of NO{sub x} storage and intermediate gas species in determining the performance of a fully formulated, Ba-based, lean NO{sub x} trap catalyst under lean/rich cycling conditions. By experimentally resolving spatiotemporal profiles of gas composition, we found that stored NO{sub x} was significantly redistributed along the monolith axis during the rich phase of the cycle by release and subsequent downstream re-adsorption. Sulfur poisoning of upstream NO{sub x} storage sites caused the active NO{sub x}-storage zone to be displaced downstream. This axial displacement in turn influenced rich-phase NO{sub x} release and re-adsorption. As sulfur poisoning increased, NH3 slip at the catalyst exit also increased due to its formation closer to the catalyst outlet and decreased exposure to downstream oxidation by surface oxygen. N{sub 2}O formation was found to be associated with nitrate reduction rather than oxidation of NH3 by stored oxygen. We propose that the observed evolution of N{sub 2}O selectivity with sulfation can be explained by changes in the spatiotemporal distribution of NO{sub x} storage resulting in either increased or decreased number of precious-metal sites surrounded by nitrates.

  20. 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

  1. Modeling and optimization of integrated exhaust gas recirculation and multi-stage waste heat recovery in marine engines

    DEFF Research Database (Denmark)

    Kyriakidis, Fotis; Sørensen, Kim; Singh, Shobhana

    2017-01-01

    Waste heat recovery combined with exhaust gas recirculation is a promising technology that can address both the issue of NOx (nitrogen oxides) reduction and fuel savings by including a pressurized boiler. In the present study, a theoretical optimization of the performance of two different...... configurations of steam Rankine cycles, with integrated exhaust gas recirculation for a marine diesel engine, is presented. The first configuration employs two pressure levels and the second is configured with three-pressure levels. The models are developed in MATLAB based on the typical data of a large two......-stroke marine diesel engine. A turbocharger model together with a blower, a pre-scrubber and a cooler for the exhaust gas recirculation line, are included. The steam turbine, depending on the configuration, is modeled as either a dual or triple pressure level turbine. The condensation and pre-heating process...

  2. 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.

  3. 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.

  4. BWR series pump recirculation system

    International Nuclear Information System (INIS)

    Dillmann, C.W.

    1992-01-01

    This patent describes a recirculation system for driving reactor coolant water contained in an annular downcomer defined between a boiling water reactor vessel and a reactor core spaced radially inwardly therefrom. It comprises a plurality of circumferentially spaced second pumps disposed in the downcomer, each including an inlet for receiving from the downcomer a portion of the coolant water as pump inlet flow, and an outlet for discharging the pump inlet flow pressurized in the second pump as pump outlet flow; and means for increasing pressure of the pump inlet flow at the pump inlet including a first pump disposed in series flow with the second pump for first receiving the pump inlet flow from the downcomer and discharging to the second pump inlet flow pressurized in the first pump

  5. Reactor recirculation pump test loop

    International Nuclear Information System (INIS)

    Taka, Shusei; Kato, Hiroyuki

    1979-01-01

    A test loop for a reactor primary loop recirculation pumps (PLR pumps) has been constructed at Ebara's Haneda Plant in preparation for production of PLR pumps under license from Byron Jackson Pump Division of Borg-Warner Corporation. This loop can simulate operating conditions for test PLR pumps with 130 per cent of the capacity of pumps for a 1100 MWe BWR plant. A main loop, primary cooling system, water demineralizer, secondary cooling system, instrumentation and control equipment and an electric power supply system make up the test loop. This article describes the test loop itself and test results of two PLR pumps for Fukushima No. 2 N.P.S. Unit 1 and one main circulation pump for HAZ Demonstration Test Facility. (author)

  6. Switching strategy between HP (high pressure)- and LPEGR (low pressure exhaust gas recirculation) systems for reduced fuel consumption and emissions

    International Nuclear Information System (INIS)

    Luján, José Manuel; Guardiola, Carlos; Pla, Benjamín; Reig, Alberto

    2015-01-01

    EGR (Exhaust gas recirculation) plays a major role in current Diesel internal combustion engines as a cost-effective solution to reduce NO_x emissions. EGR systems will suffer a significant evolution with the introduction of NO_x after-treatment and the proliferation of more complex EGR architectures such as low pressure EGR or dual EGR. In this paper the combination of HPEGR (high pressure EGR) LPEGR (low pressure EGR) is presented as a method to minimise fuel consumption with reduced NO_x emissions. Particularly, the paper proposes to switch between HPEGR and LPEGR architectures depending on the engine operating conditions in order to exploit the potential of both systems. In this sense, given a driving cycle, in the case at hand the NEDC, the proposed strategy seeks the EGR layout to use at each instant of the cycle to minimise the fuel consumption such that NO_x emissions are kept below a certain limit. The experimental results obtained show that combining both EGR systems sequentially along the NEDC allows to keep NO_x emission below a much lower limit with minimum fuel consumption. - Highlights: • The combination of HP–LPEGR reduces the NO_x with a small impact on consumption. • The switching strategy between HP – LPEGR is derived from Optimal Control Theory. • The proposed strategy is validated experimentally.

  7. Effect of Exhaust Gas Recirculation on Performance of a Diesel Engine Fueled with Waste Plastic Oil / Diesel Blends

    Directory of Open Access Journals (Sweden)

    Punitharani K.

    2017-11-01

    Full Text Available NOx emission is one of the major sources for health issues, acid rain and global warming. Diesel engine vehicles are the major sources for NOx emissions. Hence there is a need to reduce the emissions from the engines by identifying suitable techniques or by means of alternate fuels. The present investigation deals with the effect of Exhaust Gas Recirculation (EGR on 4S, single cylinder, DI diesel engine using plastic oil/Diesel blends P10 (10% plastic oil & 90% diesel in volume, P20 and P30 at various EGR rates. Plastic oil blends were able to operate in diesel engines without any modifications and the results showed that P20 blend had the least NOx emission quantity.

  8. 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.

  9. 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

  10. Gas Turbines: ''low NOx'' technologies at EGT

    International Nuclear Information System (INIS)

    Anon.

    1996-01-01

    For more than 15 years, European Gas Turbines (EGT - GEC Alsthom Group) has gained an important know-how culture and can use its rich feedback experience in the domain of gas turbine emissions. The EGT gas turbine units equipped with denitrogenation technologies cover the 4 to 226 MW power range and cumulate more than 1.7 hours of functioning in the different existing installations in the world. This paper describes the economical and environmental interests of gas turbines for power production and the combustion technologies developed by EGT to reduce the NOx emissions. The selective catalytic reduction technique is the only available secondary technique with can allow NOx and CO emissions lower than 10 ppm. Other technologies involving diluent injection (water, water-fuel mixture, vapor..) are also described and were developed in several countries to reduce the emission of these pollutants. (J.S.)

  11. A recirculating stream aquarium for ecological studies.

    Science.gov (United States)

    Gordon H. Reeves; Fred H. Everest; Carl E. McLemore

    1983-01-01

    Investigations of the ecological behavior of fishes often require studies in both natural and artificial stream environments. We describe a large, recirculating stream aquarium and its controls, constructed for ecological studies at the Forestry Sciences Laboratory in Corvallis.

  12. 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...

  13. 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... RACT and NOX conformity exemption. Approval. EPA is approving the section 182(f) oxides of nitrogen (NOX) reasonably available control technology (RACT) and NOX conformity exemption request submitted by...

  14. 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

  15. Novel p47(phox)-related organizers regulate localized NADPH oxidase 1 (Nox1) activity.

    Science.gov (United States)

    Gianni, Davide; Diaz, Begoña; Taulet, Nicolas; Fowler, Bruce; Courtneidge, Sara A; Bokoch, Gary M

    2009-09-15

    The mechanisms that determine localized formation of reactive oxygen species (ROS) through NADPH (reduced form of nicotinamide adenine dinucleotide phosphate) oxidase (Nox) family members in nonphagocytic cells are unknown. We show that the c-Src substrate proteins Tks4 (tyrosine kinase substrate with four SH3 domains) and Tks5 are functional members of a p47(phox)-related organizer superfamily. Tks proteins selectively support Nox1 and Nox3 (and not Nox2 and Nox4) activity in reconstituted cellular systems and interact with the NoxA1 activator protein through an Src homology 3 domain-mediated interaction. Endogenous Tks4 is required for Rac guanosine triphosphatase- and Nox1-dependent ROS production by DLD1 colon cancer cells. Our results are consistent with the Tks-mediated recruitment of Nox1 to invadopodia that form in DLD1 cells in a Tks- and Nox-dependent fashion. We propose that Tks organizers represent previously unrecognized members of an organizer superfamily that link Nox to localized ROS formation.

  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. Application of numerical modeling of selective NOx reduction by hydrocarbon under diesel transient conditions in consideration of hydrocarbon adsorption and desorption process

    International Nuclear Information System (INIS)

    Watanabe, Y.; Asano, A.; Banno, K.; Yokota, K.; Sugiura, M.

    2001-01-01

    A model of NO x selective reduction by hydrocarbon (HC) was developed, which takes into account the adsorption and desorption of HC. The model was applied for predicting the performance of a De-NO x catalytic reactor, working under transient conditions such as a legislative driving cycle. Diesel fuel was used as a supplemental reductant. The behavior of HC and NO x reactions and HC adsorption and desorption has been simulated successfully by our numerical approach under the transient conditions of the simulated Japanese 10-15 driving cycle. Our model is expected to optimize the design of selective diesel NO x reduction systems using a diesel fuel as a supplemental reductant

  18. Influence of cooled exhaust gas recirculation on performance, emissions and combustion characteristics of LPG fuelled lean burn SI engine

    Science.gov (United States)

    Ravi, K.; Pradeep Bhasker, J.; Alexander, Jim; Porpatham, E.

    2017-11-01

    On fuel perspective, Liquefied Petroleum Gas (LPG) provides cleaner emissions and also facilitates lean burn signifying less fuel consumption and emissions. Lean burn technology can attain better efficiencies and lesser combustion temperatures but this temperature is quite sufficient to facilitate formation of nitrogen oxide (NOx). Exhaust Gas Recirculation (EGR) for NOx reduction has been considered allover but extremely little literatures exist on the consequence of EGR on lean burn LPG fuelled spark ignition (SI) engine. The following research is carried out to find the optimal rate of EGR addition to reduce NOx emissions without settling on performance and combustion characteristics. A single cylinder diesel engine is altered to operate as LPG fuelled SI engine at a compression ratio of 10.5:1 and arrangements to provide different ratios of cooled EGR in the intake manifold. Investigations are done to arrive at optimum ratio of the EGR to reduce emissions without compromising on performance. Significant reductions in NOx emissions alongside HC and CO emissions were seen. Higher percentages of EGR further diluted the charge and lead to improper combustion and thus increased hydrocarbon emissions. Cooled EGR reduced the peak in-cylinder temperature which reduced NOx emissions but lead to misfire at lower lean limits.

  19. Characteristics of fundamental combustion and NOx emission using various rank coals.

    Science.gov (United States)

    Kim, Sung Su; Kang, Youn Suk; Lee, Hyun Dong; Kim, Jae-Kwan; Hong, Sung Chang

    2011-03-01

    Eight types of coals of different rank were selected and their fundamental combustion characteristics were examined along with the conversion of volatile nitrogen (N) to nitrogen oxides (NOx)/fuel N to NOx. The activation energy, onset temperature, and burnout temperature were obtained from the differential thermogravimetry curve and Arrhenius plot, which were derived through thermo-gravimetric analysis. In addition, to derive the combustion of volatile N to NOx/fuel N to NOx, the coal sample, which was pretreated at various temperatures, was burned, and the results were compared with previously derived fundamental combustion characteristics. The authors' experimental results confirmed that coal rank was highly correlated with the combustion of volatile N to NOx/fuel N to NOx.

  20. NGL recovery increase through natural gasoline recirculation

    Energy Technology Data Exchange (ETDEWEB)

    Rivas M., M.; Bracho, J.L.; Murray, J. [Lagoven S.A., Maracaibo (Venezuela). Western Div.

    1997-12-31

    Given that the gas being processed in the compression plants Tia Juana 2 (PCTJ-2) and Tia Juana 3 (PCTJ-3) of Lagoven, S.A., an operating affiliate of Petroleos de Venezuela, S.A. has become learner through time, current production of natural gas liquids (NGL) and plant efficiency are significantly lower, compared to design and first obtained values. In this sense and aimed at increasing propane production, an optimization study on condensate stream recirculation and absorber installation was carried out to affect the process equilibrium constants thereby obtaining deeper extraction. Recirculation streams options were recirculation of natural gasoline obtained from the downstream fractionation process and recirculation of a conditioned, unfractionated, deethanized condensate stream. From the study, the natural gasoline recirculation scheme was determined to be the most efficient NGL recovery process. Accordingly, Lagoven, S.A. has undertaken a project to carry out this optimization scheme in PCTJ-2 and PCTJ-3. Construction stages are currently underway with completion scheduled at the end of 1997.

  1. BWR recirculation pump diagnostic expert system

    International Nuclear Information System (INIS)

    Chiang, S.C.; Morimoto, C.N.; Torres, M.R.

    2004-01-01

    At General Electric (GE), an on-line expert system to support maintenance decisions for BWR recirculation pumps for nuclear power plants has been developed. This diagnostic expert system is an interactive on-line system that furnishes diagnostic information concerning BWR recirculation pump operational problems. It effectively provides the recirculation pump diagnostic expertise in the plant control room continuously 24 hours a day. The expert system is interfaced to an on-line monitoring system, which uses existing plant sensors to acquire non-safety related data in real time. The expert system correlates and evaluates process data and vibration data by applying expert rules to determine the condition of a BWR recirculation pump system by applying knowledge based rules. Any diagnosis will be automatically displayed, indicating which pump may have a problem, the category of the problem, and the degree of concern expressed by the validity index and color hierarchy. The rules incorporate the expert knowledge from various technical sources such as plant experience, engineering principles, and published reports. These rules are installed in IF-THEN formats and the resulting truth values are also expressed in fuzzy terms and a certainty factor called a validity index. This GE Recirculation Pump Expert System uses industry-standard software, hardware, and network access to provide flexible interfaces with other possible data acquisition systems. Gensym G2 Real-Time Expert System is used for the expert shell and provides the graphical user interface, knowledge base, and inference engine capabilities. (author)

  2. NOx reduction using biomass as reburning fuel

    Energy Technology Data Exchange (ETDEWEB)

    Niu Sheng-li; Lu Chun-mei; Gao Pan; Han Kui-hua; Geng Ping; Cheng Zhong-jie [Shandong University, Jinan (China). School of Energy and Power Engineering

    2008-10-15

    A series of experiments were conducted in a multiple-functional combustion test bed with several kinds of biomass as reburning fuel to reduce NOx. The character and experimental parameters are, emphasized to examine the influences on NOx reduction. The results show that biomass could get about 55% to 70% NOx reduction. Within a certain range of the parameters tested, NOx reduction increases with the increasing temperature of reburning zone and initial concentration of NOx and with decreasing excess air ratio and diameter of fuel particle. Under the same test conditions, cornstalk gets the highest NOx reduction and wheat straw, peanut shell, wood chip follow in turn. 14 refs., 7 figs., 1 tab.

  3. Flue gas recirculation to pellets burner

    International Nuclear Information System (INIS)

    Loefgren, B.E.; Blohm, T.

    1999-05-01

    The aim of this project has been to study the influence of flue gas recirculation on the combustion results. Primarily regarding the turbulence, stability and air surplus of the flame, but also the influence on environmental factors (CO and unburnt hydrocarbons). Also studied was the possibility of automatic control of the mixing of recirculating flue gases in the combustion process through the use of a λ-sond and O 2 control Project report from the program: Small scale combustion of biofuels. 9 figs, 8 tabs

  4. 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.

  5. The bio-ethanol production with the thin stillage recirculation

    OpenAIRE

    M. Rakin; J. Pejin; O. Grujić; Lj. Mojović; D. Pejin

    2009-01-01

    In this paper, the bioethanol production with the thin stillage recirculation in mashing was investigated. The mashing was performed with recirculation of: 0, 10, 20 and 30 % of the thin stillage. The thin stillage recirculation was repeated six times. In the experiment without the thin stillage, the recirculation bioethanol yield (compared to the theoretical yield) was 97.96 %, which implicates that the experiment conditions were chosen and performed well. With the addition of the thin still...

  6. Engineering systems designs for a recirculating heavy ion induction accelerator

    International Nuclear Information System (INIS)

    Newton, M.A.; Barnard, J.J.; Reginato, L.L.; Yu, S.S.

    1991-05-01

    Recirculating heavy ion induction accelerators are being investigated as possible drivers for heavy ion fusion. Part of this investigation has included the generation of a conceptual design for a recirculator system. This paper will describe the overall engineering conceptual design of this recirculator, including discussions of the dipole magnet system, the superconducting quadrupole system and the beam acceleration system. Major engineering issues, evaluation of feasibility, and cost tradeoffs of the complete recirculator system will be presented and discussed. 5 refs., 4 figs

  7. State Estimation in the Automotive SCR DeNOx Process

    DEFF Research Database (Denmark)

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

    2012-01-01

    on exhaust gas emissions. For advanced control, e.g. Model Predictive Control (MPC), of the SCR process, accurate state estimates are needed. We investigate the performance of the ordinary and the extended Kalman filters based on a simple first principle system model. The performance is tested through......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...

  8. 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.

  9. Production of cobia in recirculating systems

    Science.gov (United States)

    Only limited information exists with respect to rearing juvenile cobia Rachycentron canadum to stocker and marketable sizes using recirculating aquaculture systems (RAS). To investigate this topic, two rearing trials were conducted using commercial scale RAS. In Trial 1, juvenile cobia (29 g) we...

  10. NOx PREDICTION FOR FBC BOILERS USING EMPIRICAL MODELS

    Directory of Open Access Journals (Sweden)

    Jiří Štefanica

    2014-02-01

    Full Text Available Reliable prediction of NOx emissions can provide useful information for boiler design and fuel selection. Recently used kinetic prediction models for FBC boilers are overly complex and require large computing capacity. Even so, there are many uncertainties in the case of FBC boilers. An empirical modeling approach for NOx prediction has been used exclusively for PCC boilers. No reference is available for modifying this method for FBC conditions. This paper presents possible advantages of empirical modeling based prediction of NOx emissions for FBC boilers, together with a discussion of its limitations. Empirical models are reviewed, and are applied to operation data from FBC boilers used for combusting Czech lignite coal or coal-biomass mixtures. Modifications to the model are proposed in accordance with theoretical knowledge and prediction accuracy.

  11. O3 and NOx Exchange

    NARCIS (Netherlands)

    Loubet, B.; Castell, J.F.; Laville, P.; Personne, E.; Tuzet, A.; Ammann, C.; Emberson, L.; Ganzeveld, L.; Kowalski, A.S.; Merbold, L.; Stella, P.; Tuovinen, J.P.

    2015-01-01

    This discussion was based on the background document “Review on modelling atmosphere-biosphere exchange of Ozone and Nitrogen oxides”, which reviews the processes contributing to biosphere-atmosphere exchange of O3 and NOx, including stomatal and non-stomatal exchange of O3 and NO, NO2.

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

    Science.gov (United States)

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

    2016-09-01

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

  13. 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

    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....../CGO electrode by selectively trapping NO2 in the form of nitrate over the BaO sites and provided availability for a direct reduction of the stored nitrate. The BaO-Pt-Al2O3 layer enhanced the NOx adsorption and promoted the formation of NO2 due to the NO oxidation ability of the Pt catalyst, but hindered...... the gas diffusion to the reaction sites....

  14. Radionuclide buildup in BWR [boiling water reactor] reactor coolant recirculation piping

    International Nuclear Information System (INIS)

    Duce, S.W.; Marley, A.W.; Freeman, A.L.

    1989-12-01

    Since the spring of 1985, thermoluminescent dosimeter, dose rate, and gamma spectral data have been acquired on the contamination of boiling water reactor primary coolant recirculation systems as part of a Nuclear Regulatory Commission funded study. Data have been gathered for twelve facilities by taking direct measurements and/or obtaining plant and vendor data. The project titled, ''Effectiveness and Safety Aspects of Selected Decontamination Processes'' (October 1983) initially reviewed the application of chemical decontamination processes on primary coolant recirculation system piping. Recontamination of the system following pipe replacement or chemical decontamination was studied as a second thrust of this program. During the course of this study, recontamination measurements were made at eight different commercial boiling water reactors. At four of the reactors the primary coolant recirculation system piping was chemically decontaminated. At the other four the piping was replaced. Vendor data were obtained from two boiling water reactors that had replaced the primary coolant recirculation system piping. Contamination measurements were made at two newly operating boiling water reactors. This report discusses the results of these measurements as they apply to contamination and recontamination of boiling water reactor recirculation piping. 16 refs., 29 figs., 9 tabs

  15. Recirculator SALO. The physical foundation

    International Nuclear Information System (INIS)

    Guk, I.S.; Dovbnya, A.N.; Kononenko, S.G.; Peev, F.A.; Botman, J.I.M.

    2015-01-01

    It is presented the results of research carried out for the creation of a modern accelerator complex that could solve fundamental and applied problems of nuclear physics. It is selected and optimized scheme of magneto-optical system that meets all the requirements of the experiments with beams. Designs of magnetic devices have been developed and pre-production models have been made. Examination of influence non-linear component of magnet fields on beam parameters on an accelerator exit has been spent

  16. The radon daughter radiation hazard in controlled recirculation systems

    International Nuclear Information System (INIS)

    Rolle, R.; Burton, R.C.

    1987-01-01

    In deep South African gold mines, controlled recirculation systems with air cooling are being used to an increasing extent to improve the thermal environment. Recirculation causes some air to reside in the working area for a longer time than would have occurred without recirculation. Since radon daughters grow spontaneously from radon there is some concern that, with the extended residence time, the potential radiation hazard could increase to an unacceptable level. This paper describes the results obtained from a theoretical model of a controlled recirculation system. Guidelines for the design of recirculation systems to control the radon daughter radiation, and to keep it within acceptable limits are provided. 3 refs., 5 figs

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

    Science.gov (United States)

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

    2003-01-01

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

  18. IC ENGINE SUPERCHARGING AND EXHAUST GAS RECIRCULATION USING JET COMPRESSOR

    Directory of Open Access Journals (Sweden)

    Adhimoulame Kalaisselvane

    2010-01-01

    Full Text Available Supercharging is a process which is used to improve the performance of an engine by increasing the specific power output whereas exhaust gas recirculation reduces the NOx produced by engine because of supercharging. In a conventional engine, supercharger functions as a compressor for the forced induction of the charge taking mechanical power from the engine crankshaft. In this study, supercharging is achieved using a jet compressor. In the jet compressor, the exhaust gas is used as the motive stream and the atmospheric air as the propelled stream. When high pressure motive stream from the engine exhaust is expanded in the nozzle, a low pressure is created at the nozzle exit. Due to this low pressure, atmospheric air is sucked into the expansion chamber of the compressor, where it is mixed and pressurized with the motive stream. The pressure of the mixed stream is further increased in the diverging section of the jet compressor. A percentage volume of the pressurized air mixture is then inducted back into the engine as supercharged air and the balance is let out as exhaust. This process not only saves the mechanical power required for supercharging but also dilutes the constituents of the engine exhaust gas thereby reducing the emission and the noise level generated from the engine exhaust. The geometrical design parameters of the jet compressor were obtained by solving the governing equations using the method of constant rate of momentum change. Using the theoretical design parameters of the jet compressor, a computational fluid dinamics analysis using FLUENT software was made to evaluate the performance of the jet compressor for the application of supercharging an IC engine. This evaluation turned out to be an efficient diagnostic tool for determining performance optimization and design of the jet compressor. A jet compressor was also fabricated for the application of supercharging and its performance was studied.

  19. Exhaust gas recirculation for advanced diesel combustion cycles

    International Nuclear Information System (INIS)

    Asad, Usman; Zheng, Ming

    2014-01-01

    Highlights: • Analysis of the incremental (cycle-by-cycle) build-up of EGR. • Proposed one-step equations for transient/steady-state gas concentration estimation. • Defined an in-cylinder excess-air ratio to account for the recycled oxygen with EGR. • Demonstrated the use of intake oxygen as a reliable measure of EGR effectiveness. • Demonstrated the impact of engine load and intake pressure on EGR effectiveness. - Abstract: Modern diesel engines tend to utilize significantly large quantities of exhaust gas recirculation (EGR) and high intake pressures across the engine load range to meet NOx targets. At such high EGR rates, the combustion process and exhaust emissions tend to exhibit a marked sensitivity to small changes in the EGR quantity, resulting in unintended deviations from the desired engine performance characteristics (energy efficiency, emissions, stability). An accurate estimation of EGR and its effect on the intake dilution are, therefore, necessary to enable its application during transient engine operation or unstable combustion regimes. In this research, a detailed analysis that includes estimation of the transient (cycle-by-cycle) build-up of EGR and the time (engine cycles) required to reach the steady-state EGR operation has been carried out. One-step global equations to calculate the transient and steady-state gas concentrations in the intake and exhaust are proposed. The effects of engine load and intake pressure on EGR have been examined and explained in terms of intake charge dilution and in-cylinder excess-air ratio. The EGR analysis is validated against a wide range of empirical data that include low temperature combustion cycles, intake pressure and load sweeps. This research intends to not only formulate a clear understanding of EGR application for advanced diesel combustion but also to set forth guidelines for transient analysis of EGR

  20. 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.

  1. 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.

  2. Preoperational test report, recirculation condenser cooling systems

    International Nuclear Information System (INIS)

    Clifton, F.T.

    1997-01-01

    This represents a preoperational test report for Recirculation Condenser Systems, Project W-030. Project W-030 provides a ventilation upgrade for the four Aging Waste Facility tanks. The four system provide condenser cooling water for vapor space cooling of tanks AY1O1, AY102, AZ1O1, AZ102. Each system consists of a valved piping loop, a pair of redundant recirculation pumps, a closed-loop evaporative cooling tower, and supporting instrumentation; equipment is located outside the farm on concrete slabs. Piping is routed to the each ventilation condenser inside the farm via below-grade concrete trenches. The tests verify correct system operation and correct indications displayed by the central Monitor and Control System

  3. Preoperational test report, recirculation condenser cooling systems

    Energy Technology Data Exchange (ETDEWEB)

    Clifton, F.T.

    1997-11-04

    This represents a preoperational test report for Recirculation Condenser Systems, Project W-030. Project W-030 provides a ventilation upgrade for the four Aging Waste Facility tanks. The four system provide condenser cooling water for vapor space cooling of tanks AY1O1, AY102, AZ1O1, AZ102. Each system consists of a valved piping loop, a pair of redundant recirculation pumps, a closed-loop evaporative cooling tower, and supporting instrumentation; equipment is located outside the farm on concrete slabs. Piping is routed to the each ventilation condenser inside the farm via below-grade concrete trenches. The tests verify correct system operation and correct indications displayed by the central Monitor and Control System.

  4. Exhaust gas recirculation system for an internal combustion engine

    Science.gov (United States)

    Wu, Ko-Jen

    2013-05-21

    An exhaust gas recirculation system for an internal combustion engine comprises an exhaust driven turbocharger having a low pressure turbine outlet in fluid communication with an exhaust gas conduit. The turbocharger also includes a low pressure compressor intake and a high pressure compressor outlet in communication with an intake air conduit. An exhaust gas recirculation conduit fluidly communicates with the exhaust gas conduit to divert a portion of exhaust gas to a low pressure exhaust gas recirculation branch extending between the exhaust gas recirculation conduit and an engine intake system for delivery of exhaust gas thereto. A high pressure exhaust gas recirculation branch extends between the exhaust gas recirculation conduit and the compressor intake and delivers exhaust gas to the compressor for mixing with a compressed intake charge for delivery to the intake system.

  5. Effects of recirculation in a three-tank pilot-scale system for pharmaceutical removal with powdered activated carbon.

    Science.gov (United States)

    Kårelid, Victor; Larsson, Gen; Björlenius, Berndt

    2017-05-15

    The removal of pharmaceutically active compounds by powdered activated carbon (PAC) in municipal wastewater is a promising solution to the problem of polluted recipient waters. Today, an efficient design strategy is however lacking with regard to high-level overall, and specific, substance removal in the large scale. The performance of PAC-based removal of pharmaceuticals was studied in pilot-scale with respect to the critical parameters; contact time and PAC dose using one PAC product selected by screening in bench-scale. The goal was a minimum of 95% removal of the pharmaceuticals present in the evaluated municipal wastewater. A set of 21 pharmaceuticals was selected from an initial 100 due to their high occurrence in the effluent water of two selected wastewater treatment plants (WWTPs) in Sweden, whereof candidates discussed for future EU regulation directives were included. By using recirculation of PAC over a treatment system using three sequential contact tanks, a combination of the benefits of powdered and granular carbon performance was achieved. The treatment system was designed so that recirculation could be introduced to any of the three tanks to investigate the effect of recirculation on the adsorption performance. This was compared to use of the setup, but without recirculation. A higher degree of pharmaceutical removal was achieved in all recirculation setups, both overall and with respect to specific substances, as compared to without recirculation. Recirculation was tested with nominal contact times of 30, 60 and 120 min and the goal of 95% removal could be achieved already at the shortest contact times at a PAC dose of 10-15 mg/L. In particular, the overall removal could be increased even to 97% and 99%, at 60 and 120 min, respectively, when the recirculation point was the first tank. Recirculation of PAC to either the first or the second contact tank proved to be comparable, while a slightly lower performance was observed with recirculation to

  6. 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...

  7. The bio-ethanol production with the thin stillage recirculation

    Directory of Open Access Journals (Sweden)

    M. Rakin

    2009-01-01

    Full Text Available In this paper, the bioethanol production with the thin stillage recirculation in mashing was investigated. The mashing was performed with recirculation of: 0, 10, 20 and 30 % of the thin stillage. The thin stillage recirculation was repeated six times. In the experiment without the thin stillage, the recirculation bioethanol yield (compared to the theoretical yield was 97.96 %, which implicates that the experiment conditions were chosen and performed well. With the addition of the thin stillage, the bioethanol yield increased and was above 100 %. Higher bioethanol yield than 100 % can be explained by the fact that the thin stillage contains carbohydrates, amino acids and yeast cells degradation products. The bioethanol yield increased with the increased number of thin stillage recirculation cycles. Dry matter content in fermenting slurry increased with the increased thin stillage quantity and the number of the thin stillage recirculation cycles (8.04 % for the first and 9.40 % for the sixth cycle. Dry matter content in thin stillage increased with the increased thin stillage quantity and the number of thin stillage recirculation cycles. Based on the obtained results it can be concluded that thin stillage recirculation increased the bioethanol yield. The highest bioethanol yields were obtained with recirculation of 10% thin stillage.

  8. Exhaust gas recirculation apparatus for internal combustion engine

    Energy Technology Data Exchange (ETDEWEB)

    Shigemori, M; Eguchi, N

    1975-01-07

    An exhaust gas recirculation device to reduce nitrogen oxides emission from internal combustion engines is described. The recirculation is achieved by employing a tube connecting between the exhaust pipe and intake tube. A throttle valve is installed within the exhaust pipe between the muffler and recirculation tube, and regulated by exhaust gas temperature. Whenever the gas temperature is high, the valve closes and increases the gas flow to the intake tube. A temperature sensor is installed within the exhaust pipe and controls a solenoid or magnetic air valve linking to the throttle valve through a relay. The recirculation tube can be cooled by a fan to improve the engine power.

  9. Exhaust gas recirculation in a homogeneous charge compression ignition engine

    Science.gov (United States)

    Duffy, Kevin P [Metamora, IL; Kieser, Andrew J [Morton, IL; Rodman, Anthony [Chillicothe, IL; Liechty, Michael P [Chillicothe, IL; Hergart, Carl-Anders [Peoria, IL; Hardy, William L [Peoria, IL

    2008-05-27

    A homogeneous charge compression ignition engine operates by injecting liquid fuel directly in a combustion chamber, and mixing the fuel with recirculated exhaust and fresh air through an auto ignition condition of the fuel. The engine includes at least one turbocharger for extracting energy from the engine exhaust and using that energy to boost intake pressure of recirculated exhaust gas and fresh air. Elevated proportions of exhaust gas recirculated to the engine are attained by throttling the fresh air inlet supply. These elevated exhaust gas recirculation rates allow the HCCI engine to be operated at higher speeds and loads rendering the HCCI engine a more viable alternative to a conventional diesel engine.

  10. Preoperational test report, recirculation ventilation systems

    International Nuclear Information System (INIS)

    Clifton, F.T.

    1997-01-01

    This represents a preoperational test report for Recirculation Ventilation Systems, Project W-030. Project W-030 provides a ventilation upgrade for the four Aging Waste Facility tanks. The system provides vapor space cooling of tanks AY1O1, AY102, AZ1O1, AZ102 and supports the ability to exhaust air from each tank. Each system consists of a valved piping loop, a fan, condenser, and moisture separator; equipment is located inside each respective tank farm in its own hardened building. The tests verify correct system operation and correct indications displayed by the central Monitor and Control System

  11. Preoperational test report, recirculation ventilation systems

    Energy Technology Data Exchange (ETDEWEB)

    Clifton, F.T.

    1997-11-11

    This represents a preoperational test report for Recirculation Ventilation Systems, Project W-030. Project W-030 provides a ventilation upgrade for the four Aging Waste Facility tanks. The system provides vapor space cooling of tanks AY1O1, AY102, AZ1O1, AZ102 and supports the ability to exhaust air from each tank. Each system consists of a valved piping loop, a fan, condenser, and moisture separator; equipment is located inside each respective tank farm in its own hardened building. The tests verify correct system operation and correct indications displayed by the central Monitor and Control System.

  12. Triplet Focusing for Recirculating Linear Muon Accelerators

    CERN Document Server

    Keil, Eberhard

    2001-01-01

    Focusing by symmetrical triplets is studied for the linear accelerator lattices in recirculating muon accelerators with several passes where the ratio of final to initial muon energy is about four. Triplet and FODO lattices are compared. At similar acceptance, triplet lattices have straight sections for the RF cavities that are about twice as long as in FODO lat-tices. For the same energy gain, the total lengths of the linear accelerators with triplet lattices are about the same as of those with FODO lattices.

  13. Formation of fuel NOx during black-liquor combustion

    International Nuclear Information System (INIS)

    Nichols, K.M.; Lien, S.J.

    1993-01-01

    Fuel NOx and thermal NOx were measured in combustion gases from black liquors in two laboratory furnaces. Combustion at 950 C in air (8% O 2 ) produced NOx concentrations of 40-80ppm. Combustion at 950 C in synthetic air containing no nitrogen (21% 0 2 in Ar) produced the same result, demonstrating that all of the NOx produced during combustion at 950 C was fuel NOx. Formation of fuel NOx increased moderately with increasing temperature in the range of 800-1,000 C, but temperature sensitivity of fuel NOx was much less than that of thermal NOx. The results imply that the major source of NOx in recovery furnace emissions is the fuel NOx in recovery furnace formed by conversion of liquor-bound nitrogen during combustion. This is consistent with thermal NOx theory, which postulates that black-liquor combustion temperatures are too low to generate significant amounts of thermal NOx

  14. Biodiesel unsaturation degree effects on diesel engine NOx emissions and cotton wick flame temperature

    Directory of Open Access Journals (Sweden)

    Abdullah Mohd Fareez Edzuan

    2017-01-01

    Full Text Available 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 coconut oils are selected as the feedstock based on their unsaturation degree. Biodiesel blends of B20 were used to fuel a single cylinder diesel engine and exhaust emissions were sampled directly at exhaust tailpipe with a flue gas analyser. Biodiesel flame temperature was measured from a cotton wick burned in simple atmospheric conditions using a thermocouple. Fourier transform infrared (FTIR spectrometer was also used to identify the functional groups presence in the biodiesel blends. Oxygen content in biodiesel may promote complete combustion as the NOx emissions and flame temperatures were increased while the carbon monoxide (CO emissions were decreased for all biodiesel blends. It is interesting to note that the NOx emissions and flame temperatures were directly proportional with biodiesel unsaturation degree. It might be suggested that apart from excess oxygen and free radical formation, higher NOx emissions can also be caused by the elevated flame temperatures due to the presence of double bonds in unsaturated biodiesel.

  15. Mechanistic Investigation of the Reduction of NOx over Pt- and Rh-Based LNT Catalysts

    Directory of Open Access Journals (Sweden)

    Lukasz Kubiak

    2016-03-01

    Full Text Available The influence of the noble metals (Pt vs. Rh on the NOx storage reduction performances of lean NOx trap catalysts is here investigated by transient micro-reactor flow experiments. The study indicates a different behavior during the storage in that the Rh-based catalyst showed higher storage capacity at high temperature as compared to the Pt-containing sample, while the opposite is seen at low temperatures. It is suggested that the higher storage capacity of the Rh-containing sample at high temperature is related to the higher dispersion of Rh as compared to Pt, while the lower storage capacity of Rh-Ba/Al2O3 at low temperature is related to its poor oxidizing properties. The noble metals also affect the catalyst behavior upon reduction of the stored NOx, by decreasing the threshold temperature for the reduction of the stored NOx. The Pt-based catalyst promotes the reduction of the adsorbed NOx at lower temperatures if compared to the Rh-containing sample, due to its superior reducibility. However, Rh-based material shows higher reactivity in the NH3 decomposition significantly enhancing N2 selectivity. Moreover, formation of small amounts of N2O is observed on both Pt- and Rh-based catalyst samples only during the reduction of highly reactive NOx stored at 150 °C, where NOx is likely in the form of nitrites.

  16. 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)

  17. Impact of capillary rise and recirculation on simulated crop yields

    NARCIS (Netherlands)

    Kroes, J.G.; Supit, I.; Dam, van J.C.; Walsum, van P.E.V.; Mulder, H.M.

    2018-01-01

    Upward soil water flow is a vital supply of water to crops. The purpose of this study is to determine if upward flow and recirculated percolation water can be quantified separately, and to determine the contribution of capillary rise and recirculated water to crop yield and groundwater recharge.

  18. Engineering development for a small-scale recirculator experiment

    International Nuclear Information System (INIS)

    Newton, M.A.; Deadrick, F.J.; Hanks, R.L.; Hawkins, S.A.; Holm, K.A.; Kirbie, H.C.; Karpenko, V.P.; Nattrass, L.A.; Longinotti, D.B.

    1995-01-01

    Lawrence Livermore National Laboratory (LLNL) is evaluating the physics and technology of recirculating induction accelerators for heavy-ion inertial-fusion drivers. As part of this evaluation, the authors are building a small-scale recirculator to demonstrate the concept and to use as a test bed for the development of recirculator technologies. System designs have been completed and components are presently being designed and developed for the small-scale recirculator. This paper discusses results of the design and development activities that are presently being conducted to implement the small-scale recirculator experiments. An, overview of the system design is presented along with a discussion of the implications of this design on the mechanical and electrical hardware. The paper focuses primarily on discussions of the development and design of the half-lattice period hardware and the advanced solid-state modulator

  19. Device for controlling a recirculation flow in a reactor

    International Nuclear Information System (INIS)

    Shida, Toichi; Tohei, Kazushige; Hirose, Masao; Nakamura, Hideo.

    1976-01-01

    Object: To provide an emergency cut-off valve in a recirculation system in a reactor to control the recirculation at the time of turbine trip or load cut-off, thereby relieving excessive increase in heat output of fuel. Structure: A recirculation pump is driven through a recirculation pump motor by an AC generator, which is driven by a driving motor through a fluid coupling, so that reactor water passes the emergency cut-off valve and recirculation flow stop valve and then passes a jet pump into the core. At the time of turbine trip or load cut-off, the emergency cut-off valve is closed by a hydraulic circuit, whereby core flow is merely decreased by 20 to 30% in a short period of time to restrain excessive increase in heat output. (Yoshino, Y.)

  20. NGL recovery being hiked by natural-gasoline recirculation

    Energy Technology Data Exchange (ETDEWEB)

    Rivas M, M.; Bracho, J.L. [Lagoven S.A., Maracaibo (Venezuela); Murray, J.E. [Murray (James E.), Corpus Christi, TX (United States)

    1997-07-07

    Construction will be completed later this year at two compression plants operated by Lagoven, S.A., to install natural-gasoline recirculation to improve NGL recovery. The project is the result of a study of condensate-stream recirculation and absorber operations at the compression plants Tia Juana 2 (PCTJ-2) and Tia Juana 3 (PCTJ-3), offshore Lake Maracaibo in western Venezuela. The PCTJ-2 and PCTJ-3 gas compression plants have two systems: gas compression and NGL extraction. Previous analysis of the NGL extraction and fractionation processes of Lagoven determined that there are two practical and attractive alternatives for the recirculation of the condensate streams in PCTJ-2 and 3: recirculation of natural gasoline from the Ule LPG plant; recirculation of a conditioned condensate from the de-ethanizer tower of each plant. Both alternatives are discussed. Also described are fractionation capacity, and modifications for adding absorption and fractionation.

  1. 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.

  2. 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.

  3. Toluene decomposition performance and NOx by-product formation during a DBD-catalyst process.

    Science.gov (United States)

    Guo, Yufang; Liao, Xiaobin; Fu, Mingli; Huang, Haibao; Ye, Daiqi

    2015-02-01

    Characteristics of toluene decomposition and formation of nitrogen oxide (NOx) by-products were investigated in a dielectric barrier discharge (DBD) reactor with/without catalyst at room temperature and atmospheric pressure. Four kinds of metal oxides, i.e., manganese oxide (MnOx), iron oxide (FeOx), cobalt oxide (CoOx) and copper oxide (CuO), supported on Al2O3/nickel foam, were used as catalysts. It was found that introducing catalysts could improve toluene removal efficiency, promote decomposition of by-product ozone and enhance CO2 selectivity. In addition, NOx was suppressed with the decrease of specific energy density (SED) and the increase of humidity, gas flow rate and toluene concentration, or catalyst introduction. Among the four kinds of catalysts, the CuO catalyst showed the best performance in NOx suppression. The MnOx catalyst exhibited the lowest concentration of O3 and highest CO2 selectivity but the highest concentration of NOx. A possible pathway for NOx production in DBD was discussed. The contributions of oxygen active species and hydroxyl radicals are dominant in NOx suppression. Copyright © 2014. Published by Elsevier B.V.

  4. Recirculating ventilation system for radioactive laboratories

    International Nuclear Information System (INIS)

    Kotrappa, P.; Menon, V.B.; Dingankar, M.V.; Chandramoleshwar, K.; Bhargava, B.L.

    1980-01-01

    Radioactive laboratories designed to handle toxic substances such as plutonium are required to have ''once through'' ventilation scheme. This is an expensive proposition particularly when conditioned air is required. A recent approach is to have recirculatory system with exhausted air passing through absolute (HEPA) filters. This scheme not only drastically reduces capital costs but also substantially cuts down maintenance and running costs. Experiments emplyoing aerosol clearance techniques were conducted to specifically establish that this new scheme meets all the health physics safety stipulations laid down for such installations. It is shown that the ''once through'' system is three times more expensive compared to the recirculation system adopted in Purnima Laboratories. Further a saving of 70% is also achieved in running and operating costs. Therefore the new approach deserves serious consideration in future planning of similar projects, particularly in view of the fact that the considerable savings achievable both in terms of money and energy are without in any way compromising on safety. (auth.)

  5. Beam Dynamics Studies in Recirculating Machines

    CERN Document Server

    Pellegrini, Dario; Latina, A

    The LHeC and the CLIC Drive Beam share not only the high-current beams that make them prone to show instabilities, but also unconventional lattice topologies and operational schemes in which the time sequence of the bunches varies along the machine. In order to asses the feasibility of these projects, realistic simulations taking into account the most worrisome effects and their interplays, are crucial. These include linear and non-linear optics with time dependent elements, incoherent and coherent synchrotron radiation, short and long-range wakefields, beam-beam effect and ion cloud. In order to investigate multi-bunch effects in recirculating machines, a new version of the tracking code PLACET has been developed from scratch. PLACET2, already integrates most of the effects mentioned before and can easily receive additional physics. Its innovative design allows to describe complex lattices and track one or more bunches accordingly to the machine operation, reproducing the bunch train splitting and recombinat...

  6. Nutrient Management in Recirculating Hydroponic Culture

    Science.gov (United States)

    Bugbee, Bruce

    2004-01-01

    There is an increasing need to recirculate and reuse nutrient solutions in order to reduce environmental and economic costs. However, one of the weakest points in hydroponics is the lack of information on managing the nutrient solution. Many growers and research scientists dump out nutrient solutions and refill at weekly intervals. Other authors have recommended measuring the concentrations of individual nutrients in solution as a key to nutrient control and maintenance. Dumping and replacing solution is unnecessary. Monitoring ions in solution is not always necessary; in fact the rapid depletion of some nutrients often causes people to add toxic amounts of nutrients to the solution. Monitoring ions in solution is interesting, but it is not the key to effective maintenance.

  7. Neural networks prove effective at NOx reduction

    Energy Technology Data Exchange (ETDEWEB)

    Radl, B.J. [Pegasus Technologies, Mentor, OH (USA)

    2000-05-01

    The availability of low cost computer hardware and software is opening up possibilities for the use of artificial intelligence concepts, notably neural networks, in power plant control applications, delivering lower costs, greater efficiencies and reduced emissions. One example of a neural network system is the NeuSIGHT combustion optimisation system, developed by Pegasus Technologies, a subsidiary of KFx Inc. It can help reduce NOx emissions, improve heat rate and enable either deferral or elimination of capital expenditures. on other NOx control technologies, such as low NOx burners, SNCR and SCR. This paper illustrates these benefits using three recent case studies. 4 figs.

  8. Recirculating induction accelerators for inertial fusion: Prospects and status

    International Nuclear Information System (INIS)

    Friedman, A.; Barnard, J.J.; Cable, M.D.

    1995-01-01

    The US is developing the physics and technology of induction accelerators for heavy-ion beam-driven inertial fusion. The recirculating induction accelerator repeatedly passes beams through the same set of accelerating and focusing elements, thereby reducing both the length and gradient of the accelerator structure. This promises an attractive driver cost, if the technical challenges associated with recirculation can be met. Point designs for recirculator drivers were developed in a multi-year study by LLNL, LBNL, and FM Technologies, and that work is briefly reviewed here. To validate major elements of the recirculator concept, we are developing a small (4-5-m diameter) prototype recirculator which will accelerate a space-charge-dominated beam of K + ions through 15 laps, from 80 to 320 keV and from 2 to 8 mA. Transverse beam confinement is effected via permanent-magnet quadrupoles; bending is via electric dipoles. This ''Small Recirculator'' is being developed in a build-and-test sequence of experiments. An injector, matching section, and linear magnetic channel using seven half-lattice periods of permanent-magnet quadrupole lenses are operational. A prototype recirculator half-lattice period is being fabricated. This paper outlines the research program, and presents initial experimental results

  9. A detailed BWR recirculation loop model for RELAP

    Energy Technology Data Exchange (ETDEWEB)

    Araiza-Martínez, Enrique, E-mail: enrique.araiza@inin.gob.mx; Ortiz-Villafuerte, Javier, E-mail: javier.ortiz@inin.gob.mx; Castillo-Durán, Rogelio, E-mail: rogelio.castillo@inin.gob.mx

    2017-01-15

    Highlights: • A new detailed BWR recirculation loop model was developed for RELAP. • All jet pumps, risers, manifold, suction and control valves, and recirculation pump are modeled. • Model is tested against data from partial blockage of two jet pumps. • For practical applications, simulation results showed good agreement with available data. - Abstract: A new detailed geometric model of the whole recirculation loop of a BWR has been developed for the code RELAP. This detailed model includes the 10 jet pumps, 5 risers, manifold, suction and control valves, and the recirculation pump, per recirculation loop. The model is tested against data from an event of partial blockage at the entrance nozzle of one jet pump in both recirculation loops. For practical applications, simulation results showed good agreement with data. Then, values of parameters considered as figure of merit (reactor power, dome pressure, core flow, among others) for this event are compared against those from the common 1 jet pump per loop model. The results show that new detailed model led to a closer prediction of the reported power change. The detailed recirculation loop model can provide more reliable boundary condition data to a CFD models for studies of, for example, flow induced vibration, wear, and crack initiation.

  10. Application of the MIT two-channel model to predict flow recirculation in WARD 61-pin blanket tests

    International Nuclear Information System (INIS)

    Huang, T.T.; Todreas, N.E.

    1983-01-01

    The preliminary application of MIT two-channel model to WARD sodium blanket tests was presented in this report. The criterion was employed to predict the recirculation for selected completed (transient and steady state) and proposed (transient only) tests. The heat loss was correlated from the results of the WARD zero power tests. The calculational results show that the criterion agrees with the WARD tests except for WARD RUN 718 for which the criterion predicts a different result from WARD data under bundle heat loss condition. However, if the test assembly is adiabatic, the calculations predict an operating point which is marginally close to the mixed-to-recirculation transition regime

  11. Application of the MIT two-channel model to predict flow recirculation in WARD 61-pin blanket tests

    International Nuclear Information System (INIS)

    Huang, T.T.; Todreas, N.E.

    1983-01-01

    The preliminary application of MIT TWO-CHANNEL MODEL to WARD sodium blanket tests was presented in this report. Our criterion was employed to predict the recirculation for selected completed (transient and steady state) and proposed (transient only) tests. The heat loss was correlated from the results of the WARD zero power tests. The calculational results show that our criterion agrees with the WARD tests except for WARD RUN 718 for which the criterion predicts a different result from WARD data under bundle heat loss condition. However, if the test assembly is adiabatic, the calculations predict an operating point which is marginally close to the mixed-to-recirculation transition regime

  12. Rise and fall of the NOx emissions trade; Opkomst en ondergang van NOx-emissiehandel

    Energy Technology Data Exchange (ETDEWEB)

    Van der Velde, R. [Royal Haskoning DHV, Amersfoort (Netherlands); Van der Kolk, J. [Van der Kolk Advies, Soest (Netherlands)

    2013-04-15

    In 2005, the Netherlands started NOx emission trading. In 2014 they are terminating these activities. Are they stopping because the targets have been realized? This article provides an overview of the developments and experiences that have ultimately led to the termination of the NOx emission trade in the Netherlands [Dutch] In 2005 is Nederland begonnen in NOx-emissiehandel. In 2014 stoppen we er weer mee. Stoppen we omdat de doelen zijn gehaald? Een overzicht wordt gegeven van de ontwikkelingen en ervaringen die uiteindelijk hebben geleid tot beeindiging van de NOx-emissiehandel in Nederland.

  13. 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.

  14. Nox regulation of smooth muscle contraction

    OpenAIRE

    Ritsick, Darren R.; Edens, William A.; Finnerty, Victoria; Lambeth, J. David

    2007-01-01

    The catalytic subunit, gp91phox (a.k.a., Nox2) of the NADPH-oxidase of mammalian phagocytes is activated by microbes and immune mediators to produce large amounts of reactive oxygen species (ROS) which participate in microbial killing. Homologs of gp91phox, the Nox and Duox enzymes, were recently described in a range of organisms, including plants, vertebrates, and invertebrates such as Drosophila melanogaster. While their enzymology and cell biology is being extensively studied in many labor...

  15. Corrosion products, activity transport and deposition in boiling water reactor recirculation systems

    International Nuclear Information System (INIS)

    Alder, H.P.; Buckley, D.; Grauer, R.; Wiedemann, K.H.

    1992-01-01

    The deposition of activated corrosion products in the recirculation loops of Boiling Water Reactors produces increased radiation levels which lead to a corresponding increase in personnel radiation dose during shut down and maintenance. The major part of this dose rate is due to cobalt-60. Based on a comprehensive literature study concerning this theme, it has been attempted to identify the individual stages of the activity build-up and to classify their importance. The following areas are discussed in detail: The origins of the corrosion products and of cobalt-59 in the reactor feedwaters; the consolidation of the cobalt in the fuel pins deposits (activation); the release and transport of cobalt-60; the build-up of cobalt-60 in the corrosion products in the recirculation loops. Existing models of the build-up of circuit radioactivity are discussed and the operating experiences from selected reactors are summarized. 90 refs, figs and tabs

  16. Data quality objectives summary report for the 107-N Basin recirculation building liquid/sediment

    International Nuclear Information System (INIS)

    Nossardi, O.A.; Miller, M.S.; Carlson, D.

    1997-01-01

    The scope of the 107-N Basin Recirculation Facility Liquid/Sediment Data Quality Objectives (DQO) exclusively involves the determination of sampling and analytical requirements during the deactivation period. The sampling requirements are primarily directed at sample characterization for comparison to decontamination and decommissioning (D and D) endpoint acceptance criteria in preparation for turnover of the facilities (listed below) to D and D organization. If determined to be waste, the sample characterization is also used for comparison with the waste acceptance criteria (WAC) of the receiving facilities for selection of the appropriate disposition. Additionally, the data generated from the characterization will be used to support the selection of available disposition options. The primary media within the scope of this DQO includes the following: Accumulated liquids and sediment contained in tanks, vessels, pump wells, sumps, associated piping, and valve pit floors; and Limited solid debris (anticipated to be discovered). Although the title of this report refers only to the 107-N Basin Recirculation Building, this DQO encompasses the following four 100-N Buildings/areas: 1310-N valve pit area inside the Radioactive Chemical Waste Treatment Pump House (silo); 1314-N Waste Pump (Overflow) Tank at the Liquid Waste Disposal Station; 105-N Lift Station pump well and valve pit areas inside the 105-N Reactor Building; and 107-N Basin Recirculation Building

  17. Emission Characteristics for a Homogeneous Charged Compression Ignition Diesel Engine with Exhaust Gas Recirculation Using Split Injection Methodology

    Directory of Open Access Journals (Sweden)

    Changhee Lee

    2017-12-01

    Full Text Available Due to the serious issues caused by air pollution and global warming, emission regulations are becoming stricter. New technologies that reduce NOx and PM emissions are needed. To cope with these social exhaust gas regulation demands, many advanced countries are striving to develop eco-friendly vehicles in order to respond to stricter emissions regulations. The homogeneous charged compression ignition engine (HCCI incorporates a multi-stage combustion engine with multiple combustion modes, catalyst, direct fuel injection and partial mixing combustion. In this study, the HCCI combustion was applied to analyze and review the results of engines applying HCCI combustion without altering the conventional engine specifications. The optimization of exhaust gas recirculation (EGR and compression ratio changes provides an optimal fuel economy. In this study, potential for optimum economy within the range of IMEP 0.8 MPa has been evaluated.

  18. Freshwater Institute: Focused on improving recirculating aquaculture system technology

    Science.gov (United States)

    Recirculating aquaculture system (RAS) technologies help to overcome barriers to domestic aquaculture expansion and enhance the sustainability of the modern fish farming industry through reduction in environmental impacts. With RAS, fish farm expansion is no longer highly constrained by competition ...

  19. Engine with pulse-suppressed dedicated exhaust gas recirculation

    Science.gov (United States)

    Keating, Edward J.; Baker, Rodney E.

    2016-06-07

    An engine assembly includes an intake assembly, a spark-ignited internal combustion engine, and an exhaust assembly. The intake assembly includes a charge air cooler disposed between an exhaust gas recirculation (EGR) mixer and a backpressure valve. The charge air cooler has both an inlet and an outlet, and the back pressure valve is configured to maintain a minimum pressure difference between the inlet of the charge air cooler and an outlet of the backpressure valve. A dedicated exhaust gas recirculation system is provided in fluid communication with at least one cylinder and with the EGR mixer. The dedicated exhaust gas recirculation system is configured to route all of the exhaust gas from the at least one cylinder to the EGR mixer for recirculation back to the engine.

  20. Modeling and simulation of the bioprocess with recirculation

    Directory of Open Access Journals (Sweden)

    Žerajić Stanko

    2007-01-01

    Full Text Available The bioprocess models with recirculation present an integration of the model of continuous bioreaction system and the model of separation system. The reaction bioprocess is integrated with separation the biomass, formed product, no consumed substrate or inhibitory substance. In this paper the simulation model of recirculation bioprocess was developed, which may be applied for increasing the biomass productivity and product biosynthesis increasing the conversion of a substrate-to-product, mixing efficiency and secondary C02 separation. The goal of the work is optimal bioprocess configuration, which is determined by simulation optimization. The optimal hemostat state was used as referent. Step-by-step simulation method is necessary because the initial bioprocess state is changing with recirculation in each step. The simulation experiment confirms that at the recirculation ratio a. = 0.275 and the concentration factor C = 4 the maximum glucose conversion to ethanol and at a dilution rate ten times larger.

  1. Beam breakup in a multi-section recirculating linac

    International Nuclear Information System (INIS)

    Gluckstern, R.L.

    1986-01-01

    It has long been recognized that recirculating a beam through a linac cavity in order to provide a more efficient acceleration can also lead to an instability in which the transverse displacement on successive recirculations can excite modes which further deflect the initial beam. The effect is of particular concern for superconducting rf cavities where the high Q (or order 10 9 ) implied low starting currents for the instability. Previous work has addressed this effect by calculating the beam trajectory in a single cavity, and its effect on excitation of unwanted modes. The analysis of Gluckstern, Cooper and Channel is extended to the case of recirculation of a CW beam, and the starting current for a multi-cavity structure with several recirculations is computed. Each of the cavities is assumed to provide a simple impulse to the beam proportional to the transverse displacement in that cavity

  2. Contribution to the study of recirculating flows

    International Nuclear Information System (INIS)

    Grand, Dominique

    1975-01-01

    The technology of the integrated primary circuit of French LMFBR type reactors involves many difficulties relating to heat transfer and hydraulics of the sodium masses inside the reactor. The work reported was a basic research supporting said reactor type development. Recirculating flows were studied inside a rectangular cavity, in the presence of body forces. Results given were obtained from numerical simulation, experimental investigation and a formal theoretical analysis. Solutions were obtained using the numerical integration of the conservation equation for a planar isothermal laminar flow driven by a mobile wall. The turbulent flow was experimentally investigated, the fluid being then driven through a mixing layer in common with a channel flow. Local velocity measurements in isothermal flow were effected using a laser-anemometer. In the occurrence of heat transfer, the temperature field only was scanned; complementary data were also obtained from color Schlieren vizualisation. A theoretical study of the flow was done at high Reynolds number. The flow inside the cavity was then separated in two parts: an external part (the non-viscous core) located at the center of the cavity and an internal part, the shear region, about the walls. An inclusive solution connecting both parts was developed in the framework of the laminar flow; results obtained are in good agreement with the numerical data. (author) [fr

  3. Recirculating cooling water solute depletion models

    International Nuclear Information System (INIS)

    Price, W.T.

    1990-01-01

    Chromates have been used for years to inhibit copper corrosion in the plant Recirculating Cooling Water (RCW) system. However, chromates have become an environmental problem in recent years both in the chromate removal plant (X-616) operation and from cooling tower drift. In response to this concern, PORTS is replacing chromates with Betz Dianodic II, a combination of phosphates, BZT, and a dispersant. This changeover started with the X-326 system in 1989. In order to control chemical concentrations in X-326 and in systems linked to it, we needed to be able to predict solute concentrations in advance of the changeover. Failure to predict and control these concentrations can result in wasted chemicals, equipment fouling, or increased corrosion. Consequently, Systems Analysis developed two solute concentration models. The first simulation represents the X-326 RCW system by itself; and models the depletion of a solute once the feed has stopped. The second simulation represents the X-326, X-330, and the X-333 systems linked together by blowdown. This second simulation represents the concentration of a solute in all three systems simultaneously. 4 figs

  4. Recirculation of the Canary Current in Fall

    Science.gov (United States)

    Hernandez-Guerra, A.; Espino-Falcón, E.; Vélez-Belchí, P.; Pérez-Hernández, M. D.; Martínez, A.; Cana, L.

    2015-12-01

    CTD and LADCP data measured in October 2014 are used to describe water masses, geostrophic circulation and mass transport in the Eastern Boundary of the North Atlantic Subtropical Gyre. Initial geostrophic velocities are adjusted to velocities from the LADCP data to estimate an initial velocity at the reference layer. Final reference velocities and consequently circulation is estimated from an inverse box model applied to an ocean divided into 12 neutral density layers. This allows us to evaluate mass fluxes consistent with the thermal wind equation and mass conservation. Ekman transport derived from the Weather Research and Forecasting (WRF) model is added to the first layer and adjusted with the inverse model. The Canary Current (CC) transports southward a net mass of 3.8±0.7 Sv (1 Sv=106 m3/s≈109 kg/s) of North Atlantic Central Water (NACW) at the thermocline layers (~0-700 m) and 1.9±0.6 Sv of a mixture of Mediterranean Water (MW) and Antarctic Intermediate Water (AAIW) at intermediate layers (~800-1400 m). The CC recirculates northward at a rate of 4.8±0.8 Sv at the thermocline layers between the Lanzarote Island and the African coast (Lanzarote Passage) on this occasion. Separately, at intermediate layers, AAIW flows northward at a rate of 2.4±0.6 Sv through the Lanzarote Passage transported by the Intermediate Poleward Undercurrent (IPUC).

  5. Exhaust gas recirculation – Zero dimensional modelling and characterization for transient diesel combustion control

    International Nuclear Information System (INIS)

    Asad, Usman; Tjong, Jimi; Zheng, Ming

    2014-01-01

    Highlights: • Zero-dimensional EGR model for transient diesel combustion control. • Detailed analysis of EGR effects on intake, cylinder charge and exhaust properties. • Intake oxygen validated as an operating condition-independent measure of EGR. • Quantified EGR effectiveness in terms of NOx emission reduction. • Twin lambda sensor technique for estimation of EGR/in-cylinder parameters. - Abstract: The application of exhaust gas recirculation (EGR) during transient engine operation is a challenging task since small fluctuations in EGR may cause larger than acceptable spikes in NOx/soot emissions or deterioration in the combustion efficiency. Moreover, the intake charge dilution at any EGR ratio is a function of engine load and intake pressure, and typically changes during transient events. Therefore, the management of EGR during transient engine operation or advanced combustion cycles (that are inherently less stable) requires a fundamental understanding of the transient EGR behaviour and its impact on the intake charge development. In this work, a zero-dimensional EGR model is described to estimate the transient (cycle-by-cycle) progression of EGR and the time (engine cycles) required for its stabilization. The model response is tuned to a multi-cylinder engine by using an overall engine system time-constant and shown to effectively track the transient EGR changes. The impact of EGR on the actual air–fuel ratio of the cylinder charge is quantified by defining an in-cylinder excess-air ratio that accounts for the oxygen in the recycled exhaust gas. Furthermore, a twin lambda sensor (TLS) technique is implemented for tracking the intake dilution and in-cylinder excess-air ratio in real-time. The modelling and analysis results are validated against a wide range of engine operations, including transient and steady-state low temperature combustion tests

  6. Transport and error sensitivity in a heavy-ion recirculator

    International Nuclear Information System (INIS)

    Sharp, W.M.; Barnard, J.J.; Yu, S.S.

    1991-05-01

    An envelope code has been developed to facilitate the design of a recirculating accelerator for a heavy-ion fusion reactor. A novel feature of the model is the treatment of the beam charge density as a Lagrangian fluid in the axial direction. Transport results for a preliminary recirculator design are presented, and sensitivity of the transport to errors in the magnet strength is discussed. 4 refs., 4 figs

  7. Monitoring for shaft cracks on reactor recirculation pumps

    International Nuclear Information System (INIS)

    Kowal, M.G.; O'Brien, J.T. Jr.

    1989-01-01

    The article discusses the vibration characteristics associated with a boiling water reactor (BWR) recirculation pump. It also describes the application of diagnostic techniques and shaft crack theory to an on-line diagnostic monitoring system for reactor recirculation pumps employed at Philadelphia Electric Company's Peach Bottom Atomic Power Station. Specific emphasis is placed on the unique monitoring techniques associated with these variable speed vertical pumps

  8. Possibilities for the reduction of NOx emissions

    International Nuclear Information System (INIS)

    Marx, E.

    1993-01-01

    Nitrogen oxides develop mainly in the combustion of fossil fuels based on three mechanisms: process-dependent thermal NO; prompt NO as well as fuel-dependent NO. The reaction either takes places in the area of the root of the flame or with the combustion gases. A main effect on the amount of developing nitrogen oxides have the fuel, the burner design as well as the heat generator. In the last years considerable emission reductions were attained mainly by design changes of the burner, e.g. gas burners with internal circulation, burners with external exhaust gas recirculation, burners with internal recirculation. (BWI) [de

  9. Technology development for recirculating heavy-ion accelerators

    International Nuclear Information System (INIS)

    Newton, M.A.; Kirbie, H.C.

    1993-01-01

    The open-quotes recirculator,close quotes a recirculating heavy-ion accelerator has been identified as a promising approach for an inertial fusion driver. System studies have been conducted to evaluate the recirculator on the basis of feasibility and cost. The recirculator has been shown to have significant cost advantages over other potential driver schemes, but some of the performance requirements exceed the capabilities of present technology. The system studies identified the high leverage areas where advances in technology will significantly impact the cost and performance of a recirculator. One of the high leverage areas is the modulator system which generates the acceleration potentials in the induction cells. The modulator system must be capable of generating the acceleration potentials at peak repetition rates in excess of 100 kHz with variable pulse widths. LLNL is developing a modulator technology capable of driving induction cells using the latest in solid state MOSFET technology. A small scale modulator has been built and tested to prove the concept and the next version is presently being designed. The objective is to demonstrate a modulator operating at 5 kV, 1 kA, with 0.2--1 μs pulse widths while driving an induction cell at >100 kHz within the next year. This paper describes the recirculator, the technology requirements necessary to implement it and the modulator system development that is being pursued to meet these requirements

  10. Chemical decontamination of Santa Maria de Garona NPP recirculation loops

    Energy Technology Data Exchange (ETDEWEB)

    Coello, R. [Santa Maria de Garona NPP - NUCLENOR, S.A. (Spain)

    2002-07-01

    Santa Maria de Garona is a boiling water reactor (BWR-3) with a Primary Containment type Mark 1. Its electrical power is 466 Mw and began its commercial operation in 1971. The plant currently operates in 24 month cycles. The reactor water recirculation system (RWRS) is composed of two independent loops. Each of them has a one stage vertical centrifugal recirculation pump, with a nominal flow of 2020 l/s, and ten jet pumps. It is worthy of mention that in 1986 it was started to inject hydrogen into the feedwater (concentration = 0,3 mg/l) in order to implement the chemical condition known as hydrogen water chemistry (HWC) in the primary circuit. The objective was to create an electrochemical potential below -230 mV in the RWRS which is assumed to be low enough to mitigate the intergranular stress corrosion cracking phenomena (IGSCC) in the sensitized austenitic stainless steels. Later, in 1994, the hydrogen concentration in the feedwater was increased to 0,9 mg/l in order to obtain the protection's ECP in the bottom of the reactor vessel. This feedwater hydrogen concentration has been maintained since then. The nature of the oxides that are formed in the RWRS is strongly affected by the electrochemical conditions (ECP) which have been maintained in this system. It is frequent to find oxides like Fe{sub 2}O{sub 3} (hematite), Fe{sub 3}O{sub 4} (magnetite), NiFe{sub 2}O{sub 4} (trevorite), Cr{sub 2} FeO{sub 4} (chromite), Fe{sub 3-x-y} Cr{sub x} Ni{sub y} O{sub 4} (spinels), etc. However, it is normal to find a combination of all of them in various proportions, depending on the ECP established. Radioactive isotopes of the transition metals ({sup 60}Co, {sup 54}Mn, {sup 51}Cr, {sup 59}Fe, etc.) also participate in these oxides and contribute greatly to increase the dose rate in the circuit. The chemical decontamination processes are designed for the effective dissolution of the metallic oxides present and therefore the type of process to be applied will depend

  11. In situ treatment of VOCs by recirculation technologies

    International Nuclear Information System (INIS)

    Siegrist, R.L.; Webb, O.F.; Ally, M.R.; Sanford, W.E.; Kearl, P.M.; Zutman, J.L.

    1993-06-01

    The project described herein was conducted by Oak Ridge National Laboratory (ORNL) to identify processes and technologies developed in Germany that appeared to have near-term potential for enhancing the cleanup of volatile organic compound (VOC) contaminated soil and groundwater at DOE sites. Members of the ORNL research team identified and evaluated selected German technologies developed at or in association with the University of Karlsruhe (UoK) for in situ treatment of VOC contaminated soils and groundwater. Project activities included contacts with researchers within three departments of the UoK (i.e., Applied Geology, Hydromechanics, and Soil and Foundation Engineering) during fall 1991 and subsequent visits to UoK and private industry collaborators during February 1992. Subsequent analyses consisted of engineering computations, groundwater flow modeling, and treatment process modeling. As a result of these project efforts, two processes were identified as having near-term potential for DOE: (1) the vacuum vaporizer well/groundwater recirculation well and (2) the porous pipe/horizontal well. This document was prepared to summarize the methods and results of the assessment activities completed during the initial year of the project. The project is still ongoing, so not all facets of the effort are completely described in this document. Recommendations for laboratory and field experiments are provided

  12. In situ treatment of VOCs by recirculation technologies

    Energy Technology Data Exchange (ETDEWEB)

    Siegrist, R.L.; Webb, O.F.; Ally, M.R.; Sanford, W.E. [Oak Ridge National Lab., TN (US); Kearl, P.M.; Zutman, J.L. [Oak Ridge National Lab., Grand Junction, CO (US)

    1993-06-01

    The project described herein was conducted by Oak Ridge National Laboratory (ORNL) to identify processes and technologies developed in Germany that appeared to have near-term potential for enhancing the cleanup of volatile organic compound (VOC) contaminated soil and groundwater at DOE sites. Members of the ORNL research team identified and evaluated selected German technologies developed at or in association with the University of Karlsruhe (UoK) for in situ treatment of VOC contaminated soils and groundwater. Project activities included contacts with researchers within three departments of the UoK (i.e., Applied Geology, Hydromechanics, and Soil and Foundation Engineering) during fall 1991 and subsequent visits to UoK and private industry collaborators during February 1992. Subsequent analyses consisted of engineering computations, groundwater flow modeling, and treatment process modeling. As a result of these project efforts, two processes were identified as having near-term potential for DOE: (1) the vacuum vaporizer well/groundwater recirculation well and (2) the porous pipe/horizontal well. This document was prepared to summarize the methods and results of the assessment activities completed during the initial year of the project. The project is still ongoing, so not all facets of the effort are completely described in this document. Recommendations for laboratory and field experiments are provided.

  13. Myocardin-related transcription factor regulates Nox4 protein expression

    DEFF Research Database (Denmark)

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

    2016-01-01

    translocation of MRTF. Because the Nox4 promoter harbors a serum response factor/MRTF cis-element (CC(A/T)6GG box), we asked if MRTF (and thus cytoskeleton organization) could regulate Nox4 expression. We show that Nox4 protein is robustly induced in kidney tubular cells exclusively by combined application...... TGFβ/contact disruption-provoked Nox4 protein and mRNA expression, Nox4 promoter activation, and reactive oxygen species production. Mutation of the CC(A/T)6GG box eliminates the synergistic activation of the Nox4 promoter. Jasplakinolide-induced actin polymerization synergizes with TGFβ to facilitate...... MRTF-dependent Nox4 mRNA expression/promoter activation. Moreover, MRTF inhibition prevents Nox4 expression during TGFβ-induced fibroblast-myofibroblast transition as well. Although necessary, MRTF is insufficient; Nox4 expression also requires TGFβ-activated Smad3 and TAZ/YAP, two contact...

  14. 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.

  15. 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

  16. The CO/NOx emissions of swirled, strongly pulsed jet diffusion flames

    KAUST Repository

    Liao, Ying-Hao

    2014-05-28

    The CO and NOx exhaust emissions of swirled, strongly pulsed, turbulent jet diffusion flames were studied experimentally in a coflow swirl combustor. Measurements of emissions were performed on the combustor centerline using standard emission analyzers combined with an aspirated sampling probe located downstream of the visible flame tip. The highest levels of CO emissions are generally found for compact, isolated flame puffs, which is consistent with the quenching due to rapid dilution with excess air. The imposition of swirl generally results in a decrease in CO levels by up to a factor of 2.5, suggesting more rapid and compete fuel/air mixing by imposing swirl in the coflow stream. The levels of NO emissions for most cases are generally below the steady-flame value. The NO levels become comparable to the steady-flame value for sufficiently short jet-off times. The swirled coflow air can, in some cases, increase the NO emissions due to a longer combustion residence time due to the flow recirculation within the swirl-induced recirculation zone. Scaling relations, when taking into account the impact of air dilution over an injection cycle on the flame length, reveal a strong correlation between the CO emissions and the global residence time. However, the NO emissions do not successfully correlate with the global residence time. For some specific cases, a compact flame with a simultaneous decrease in both CO and NO emissions compared to the steady flames was observed. © Copyright © Taylor & Francis Group, LLC.

  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. Spectroscopic Insights into Copper-Based Microporous Zeolites for NH3-SCR of NOx and Methane-to-Methanol Activation

    OpenAIRE

    Oord, R.

    2017-01-01

    Smog has received a lot of attention and is still a major problem in big cities all over the world. A major contribution to smog are nitrogen oxides (NOx), which are mainly produced by road transport, industrial processes and power plants. A lot of research has been put into the reduction of these pollutants, and heterogeneous catalysts have made a major contribution to this field. Selective catalytic reduction (SCR) is an efficient technology to reduce these NOx, and is already used in diese...

  19. Feasibility study of ultra-low NOx Gas turbine combustor using the RML combustion concept

    International Nuclear Information System (INIS)

    Van, Tien Giap; Hwang, Jeong Jae; Kim, Min Kuk; Ahn, Kook Young

    2016-01-01

    A new combustion concept, the so called RML, was investigated to validate its application as a gas turbine combustor for combustor outlet temperatures over 1973 K. The feasibility study of the RML combustor was conducted with zero dimensional combustion calculations. The emission characteristics of RQL, LEAN, EGR and RML combustors were compared. The calculation results showed that the RQL combustor has lower NOx emissions than the LEAN at high outlet temperature. NOx emissions of the RML combustor at equivalence ratio of the rich chamber of 2.0 can be reduced by 30 % compared with the EGR combustor, and lower than the RQL combustor at a combustor outlet temperature over 1973 K. However, the CO emissions of the RML combustor were higher than those of the LEAN and EGR combustors. Also, the possibility of applying the RML combustor to gas turbines was discussed considering residence time, equivalence ratio of the rich chamber and recirculation rate. Although further research to design and realize the proposed RML combustor is needed, this study verified that the RML concept can be successfully used in a gas turbine combustor

  20. Feasibility study of ultra-low NOx Gas turbine combustor using the RML combustion concept

    Energy Technology Data Exchange (ETDEWEB)

    Van, Tien Giap; Hwang, Jeong Jae; Kim, Min Kuk; Ahn, Kook Young [Environment and Energy Research Division, Korea Institute of Machinery and Materials (KIMM), Daejeon (Korea, Republic of)

    2016-12-15

    A new combustion concept, the so called RML, was investigated to validate its application as a gas turbine combustor for combustor outlet temperatures over 1973 K. The feasibility study of the RML combustor was conducted with zero dimensional combustion calculations. The emission characteristics of RQL, LEAN, EGR and RML combustors were compared. The calculation results showed that the RQL combustor has lower NOx emissions than the LEAN at high outlet temperature. NOx emissions of the RML combustor at equivalence ratio of the rich chamber of 2.0 can be reduced by 30 % compared with the EGR combustor, and lower than the RQL combustor at a combustor outlet temperature over 1973 K. However, the CO emissions of the RML combustor were higher than those of the LEAN and EGR combustors. Also, the possibility of applying the RML combustor to gas turbines was discussed considering residence time, equivalence ratio of the rich chamber and recirculation rate. Although further research to design and realize the proposed RML combustor is needed, this study verified that the RML concept can be successfully used in a gas turbine combustor.

  1. A new process for NOx reduction in combustion systems for the generation of energy from waste.

    Science.gov (United States)

    Gohlke, Oliver; Weber, Toralf; Seguin, Philippe; Laborel, Yann

    2010-07-01

    In the EU, emissions from energy from waste plants are largely reduced by applying the Waste Incineration Directive with its limit of 200 mg/m3(s) for NO(x) emissions. The need for further improvement is reflected by new German legislation effective as of 27 January 2009, requiring 100 mg/m3(s). Other countries are expected to follow this example due to the national emission ceilings of the Gothenburg protocol and the concluding EU directive 2001/81/EC. On the other hand, an increase in energy efficiency will be encouraged by the EU Waste Framework Directive. This is why there is a need for new technologies that make it possible to reconcile both requirements: reduced emissions and increased energy efficiency. A new process combining the internal recirculation of flue gas with ammonia or urea injection in order to achieve less then 80 mg/m3(s) of NO(x) is described. Important additional features of the process are an R1 efficiency above the required 0.65 of the EU Waste Framework Directive even with standard steam parameters of 40 bar/380 degrees C as well as low ammonia slip in the flue gas at the boiler outlet of below 10 mg/m3(s). Copyright (c) 2010 Elsevier Ltd. All rights reserved.

  2. Cyclone Boiler Field Testing of Advanced Layered NOx Control Technology in Sioux Unit 1

    Energy Technology Data Exchange (ETDEWEB)

    Marc A. Cremer; Bradley R. Adams

    2006-06-30

    A four week testing program was completed during this project to assess the ability of the combination of deep staging, Rich Reagent Injection (RRI), and Selective Non-Catalytic Reduction (SNCR) to reduce NOx emissions below 0.15 lb/MBtu in a cyclone fired boiler. The host site for the tests was AmerenUE's Sioux Unit 1, a 500 MW cyclone fired boiler located near St. Louis, MO. Reaction Engineering International (REI) led the project team including AmerenUE, FuelTech Inc., and the Electric Power Research Institute (EPRI). This layered approach to NOx reduction is termed the Advanced Layered Technology Approach (ALTA). Installed RRI and SNCR port locations were guided by computational fluid dynamics (CFD) based modeling conducted by REI. During the parametric testing, NOx emissions of 0.12 lb/MBtu were achieved consistently from overfire air (OFA)-only baseline NOx emissions of 0.25 lb/MBtu or less, when firing the typical 80/20 fuel blend of Powder River Basin (PRB) and Illinois No.6 coals. From OFA-only baseline levels of 0.20 lb/MBtu, NOx emissions of 0.12 lb/MBtu were also achieved, but at significantly reduced urea flow rates. Under the deeply staged conditions that were tested, RRI performance was observed to degrade as higher blends of Illinois No.6 were used. NOx emissions achieved with ALTA while firing a 60/40 blend were approximately 0.15 lb/MBtu. NOx emissions while firing 100% Illinois No.6 were approximately 0.165 lb/MBtu. Based on the performance results of these tests, economics analyses of the application of ALTA to a nominal 500 MW cyclone unit show that the levelized cost to achieve 0.15 lb/MBtu is well below 75% of the cost of a state of the art SCR.

  3. Influence of leachate recirculation on aerobic and anaerobic decomposition of solid wastes

    International Nuclear Information System (INIS)

    Bilgili, M. Sinan; Demir, Ahmet; Ozkaya, Bestamin

    2007-01-01

    In this study, the effect of leachate recirculation on aerobic and anaerobic degradation of municipal solid wastes is determined by four laboratory-scale landfill reactors. The options studied and compared with the traditional anaerobic landfill are: leachate recirculation, landfill aeration, and aeration with leachate recirculation. Leachate quality is regularly monitored by the means of pH, alkalinity, total dissolved solids, conductivity, oxidation-reduction potential, chloride, chemical oxygen demand, ammonia, and total Kjeldahl nitrogen, in addition to generated leachate quantity. Aerobic leachate recirculated landfill appears to be the most effective option in the removal of organic matter and ammonia. The main difference between aerobic recirculated and non-recirculated landfill options is determined at leachate quantity. Recirculation is more effective on anaerobic degradation of solid waste than aerobic degradation. Further studies are going on to determine the optimum operational conditions for aeration and leachate recirculation rates, also with the operational costs of aeration and recirculation

  4. Sulphur recirculation for reduced boiler corrosion; Minskad pannkorrosion med svavelrecirkulation

    Energy Technology Data Exchange (ETDEWEB)

    Andersson, Sven; Karlsson, Martin (Goetaverken Miljoe AB, Goeteborg (Sweden)); Blomqvist, Evalena; Baefver, Linda; Claesson, Frida; Davidsson, Kent (SP Sveriges Tekniska Forskningsinstitut, Boraas (Sweden)); Froitzheim, Jan; Pettersson, Jesper; Steenari, Britt-Marie (Chalmers Tekniska Hoegskola, Oorganisk miljoekemi, Goeteborg (Sweden))

    2010-03-15

    Sulphur recirculation is a new technology for reducing boiler corrosion and dioxin formation, which was demonstrated in full-scale tests performed at the Renova Waste to Energy plant at Saevenaes in Goeteborg (Sweden). Sulphur is recirculated from the flue gas cleaning back to the boiler, which reduces the chloride content of the deposits, which in turn reduces boiler corrosion and dioxin formation. Sulphur dioxide was separated from the flue gas in a wet scrubber by adding hydrogen peroxide, producing sulphuric acid. The sulphuric acid was injected into the furnace using nozzles with atomization air, surrounded by recirculated flue gas for improved mixing. By recirculating the sulphur, the sulphur dioxide concentration was increased in the boiler. Each sulphur atom passed the boiler several times and no external sulphur had to be added. Dioxin, ash, deposits and particle samplings together with 1000 h corrosion probe measurements were performed for normal operation (reference) and with sulphur recirculation respectively. During spring 2009, reference measurements were made and the recirculation system was installed and tested. During autumn 2009, a long term test with sulphur recirculation was made. An SO{sub 2} concentration of approximately 800 mg/m3 (n, d.g.) was maintained in the boiler by the system except during a period of extremely low sulphur content in the waste. The sulphur dioxide stack concentrations have been far below the emission limit. Sulphuric acid dew point measurements have shown that the sulphuric acid dosage did not lead to elevated SO{sub 3} concentrations, which may otherwise lead to low temperature corrosion. The chlorine content of both fly ash and boiler ash decreased and the sulphur content increased during the sulphur recirculation tests. The molar chlorine/sulphur ratio (Cl/S) decreased by two thirds in the fly ash as well as in the boiler ash, except for one sample. With sulphur recirculation in operation, the deposit growth was

  5. Investigation of induced recirculation during planned ventilation system maintenance

    Science.gov (United States)

    Pritchard, C.J.; Scott, D.F.; Noll, J.D.; Voss, B.; Leonis, D.

    2015-01-01

    The Office of Mine Safety and Health Research (OMSHR) investigated ways to increase mine airflow to underground metal/nonmetal (M/NM) mine working areas to improve miners’ health and safety. One of those areas is controlled recirculation. Because the quantity of mine air often cannot be increased, reusing part of the ventilating air can be an effective alternative, if implemented properly, until the capacity of the present system is improved. The additional airflow can be used to provide effective dilution of contaminants and higher flow velocities in the underground mine environment. Most applications of controlled recirculation involve taking a portion of the return air and passing it back into the intake to increase the air volume delivered to the desired work areas. OMSHR investigated a Nevada gold mine where shaft rehabilitation was in progress and one of the two main fans was shut down to allow reduced air velocity for safe shaft work. Underground booster fan operating pressures were kept constant to maintain airflow to work areas, inducing controlled recirculation in one work zone. Investigation into system behavior and the effects of recirculation on the working area during times of reduced primary ventilation system airflow would provide additional information on implementation of controlled recirculation into the system and how these events affect M/NM ventilation systems. The National Institute for Occupational Safety and Health monitored the ventilation district when both main fans were operating and another scenario with one of the units turned off for maintenance. Airflow and contaminants were measured to determine the exposure effects of induced recirculation on miner health. Surveys showed that 19% controlled recirculation created no change in the overall district airflow distribution and a small reduction in district fresh air intake. Total dust levels increased only modestly and respirable dust levels were also low. Diesel particulate matter

  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. Domestic manufacturing and reliability improvement of reactor water recirculation equipment

    International Nuclear Information System (INIS)

    Kobayashi, Hidekazu; Oi, Masao; Shida, Toichi; Yokomori, Takashi

    1982-01-01

    The reactor coolant recirculation system is one of the important systems to control the reactor output in BWR nuclear power plants. Its components require high reliability and maintainability as well as controllability. For many Japanese nuclear power plants, recirculation pumps, fluid couplings and others have been imported so far. Hitachi Ltd. has established a domestic manufacturing organization through the development and test of these equipment. The fundamental design conditions for these equipment are the improvement of the rate of utilization of plant facility, the capability to follow load, and output power stability. In this paper, the specifications, the investigation of moment of inertia and the design features of recirculation pumps, driving motors and variable frequency power supply systems are described. The paper also reports on the combination test implemented to evaluate the recirculation system. The combination test includes the test using water rheostat for the power source facility and the loading test for a recirculation pump. The application of those system equipment to an actual plant was analyzed and evaluated on a basis of the test data obtained. The result showed that the equipment can achieve the rate of change of reactor power of 30%/min. Those equipment have been employed for No. 2 reactor plant of the Fukushima No. 2 Nuclear Power Station, the Tokyo Electric Power Co., Inc. (Wakatsuki, Y.)

  8. NOx removal characteristics of corona radical shower with ammonia and methylamine radical injections

    Energy Technology Data Exchange (ETDEWEB)

    Urashima, K.; Ara, M.; Chang, J.S. [McMaster Univ., Hamilton, ON (Canada). Dept. of Engineering Physics; Uchida, Y. [Aichi Inst. of Technology, (Japan). Dept. of Engineering

    2010-07-01

    Air pollutants such as nitrogen oxides (NOx) and sulfur oxides (SOx) are the major cause of acid rain. There are different types of NOx and SOx conversion techniques such as wet scrubber, selective catalytic reactor, sorbent injection, and low NOx burner. Non-thermal plasma techniques have also been utilized in commercial plants, but the energy efficiency of the non-thermal plasma reactors have not yet been optimized. The direct plasma treatments of flue gases including, the electron beam, barrier discharge and pulsed corona reactors, may lose input energy to activate unwanted components of flue gases such as carbon dioxide (CO{sub 2}) and nitrogen (N{sub 2}). The corona discharge ammonia radical shower system has demonstrated significant NOx removal with higher energy efficiency for large bench scale and pilot plant tests for combustion exhausts. An experiment has also demonstrated that methane can replace ammonia as an injection gas with less NOx removal efficiency. This paper presented an experimental investigation that compared methylamine radical injection with traditional ammonia and methane radical injections. The paper discussed the bench scale test facilities and corona radical shower plasma reactor. It was concluded that the processes to form ammonium nitrate could be observed from trace white solid particles deposited on the reactor wall as observed by scanning electron microscopy pictures. 10 refs., 5 figs., 2 appendices.

  9. Photocatalytic NO_x abatement. Theory, applications, current research, and limitations

    International Nuclear Information System (INIS)

    Bloh, Jonathan Z.

    2017-01-01

    Nitrogen oxides are one of the major air pollutants that threaten our air quality and health. As a consequence, increasingly stricter regulations are in place forcing action to reduce the concentration of these dangerous compounds. Conventional methods of reducing the NO_x pollution level are reducing the emission directly at the source or restrictive measures such as low emission zones. However, there are recent reports questioning the efficacy of the strategy to reduce ambient NO_x levels solely by reducing their emissions and existing threshold values are still frequently exceeded in many European cities. Semiconductor photocatalysis presents an appealing alternative capable of removing NO_x and other air pollutants from the air once they have already been released and dispersed. Recent field tests have shown that a reduction of a few percent in NO_x values is possible with available photocatalysts. Current research focuses on further increasing the catalysts' efficacy as well as their selectivity to suppress the formation of undesired by-products. Especially using these improved materials, photocatalytic NO_x abatement could prove a very valuable contributor to better air quality.

  10. SORBENT/UREA SLURRY INJECTION FOR SIMULTANEOUS SO2/NOX REMOVAL

    Science.gov (United States)

    The combination of sorbent injection and selective noncatalytic reduction (SNCR) technologies has been investigated for simulataneous SO2/NOx removal. A slurry composed of a urea-based solution and various Ca-based sorbents was injected at a range of tempera...

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

    NARCIS (Netherlands)

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

    2014-01-01

    Methods for the determination of ship fuel sulphur content and NOx emission factors based on remote measurements have been compared in the harbour of Rotterdam and compared to direct stack emission measurements on the ferry Stena Hollandica. The methods were selected based on a review of the

  12. Indoor spread of respiratory infection by recirculation of air: a controllable hazard

    International Nuclear Information System (INIS)

    Riley, R.L.

    1980-01-01

    The overall health benefit to be derived from disinfecting air before recirculation is difficult to predict, but as more and more buildings recirculate air without disinfection, the problem of spreading infection increases. Since the cost of disinfection with uv radiation is small and the cost of morbidity from airborne infections immense, the cost-benefit ratio for disinfecting recirculated air may be attractive, even though the protection of occupants would be limited. Recirculation of air in buildings is a relatively new technology that conserves energy. Like most new technologies, it brings new hazards. Disinfection of recirculated air is an appropriate additional technique with which to counter some of the hazards of air recirculation

  13. Particle surface area and bacterial activity in recirculating aquaculture systems

    DEFF Research Database (Denmark)

    Pedersen, Per Bovbjerg; von Ahnen, Mathis; Fernandes, Paulo

    2017-01-01

    Suspended particles in recirculating aquaculture systems (RAS) provide surface area that can be colonized by bacteria. More particles accumulate as the intensity of recirculation increases thus potentially increasing the bacterial carrying capacity of the systems. Applying a recent, rapid, culture...... but may provide significant surface area. Hence, the study substantiates that particles in RAS provide surface area supporting bacterial activity, and that particles play a key role in controlling the bacterial carrying capacity at least in less intensive RAS. Applying fast, culture-independent techniques......-independent fluorometric detection method (Bactiquant®) for measuring bacterial activity, the current study explored the relationship between total particle surface area (TSA, derived from the size distribution of particles >5 μm) and bacterial activity in freshwater RAS operated at increasing intensity of recirculation...

  14. Volume reduction and material recirculation by freon decontamination

    International Nuclear Information System (INIS)

    Berners, O.; Buhmann, D.; Yamashita, Y.; Yoshiaki, M.

    1989-01-01

    This paper discusses the use of freon in a large variety of decontamination in the nuclear and non-nuclear fields. As far as the contamination is loose or smerable, surfaces of nearly all materials can be decontaminated. Freon is electrically non-conductive, chemically neutral and has a low surface tension. So it is capable of creeping under the contaminant and loosening or dissolving it. Used freon can be collected, cleaned and recirculated. Its cleaning can be done easily by evaporation at its lower vapor point of about 48 degrees C (104 degrees F). Good decontamination results could be achieved, expensive materials, tools and equipment could be recirculated. Big volumes of materials could get separated from their contaminants, which is the real radioactive waste. Freon decontamination is an effective, overall economical and approved technology to volume reduction and material recirculation

  15. NOx Emission Reduction by Oscillating Combustion

    Energy Technology Data Exchange (ETDEWEB)

    None

    2005-09-01

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

  16. 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...

  17. Stereodynamics in NO(X) + Ar inelastic collisions

    Energy Technology Data Exchange (ETDEWEB)

    Brouard, M., E-mail: mark.brouard@chem.ox.ac.uk; Chadwick, H.; Gordon, S. D. S.; Hornung, B.; Nichols, B. [The Department of Chemistry, University of Oxford, The Chemistry Research Laboratory, 12 Mansfield Road, Oxford, OX1 3TA (United Kingdom); Aoiz, F. J., E-mail: aoiz@quim.ucm.es [Departamento de Química Física, Facultad de Química, Universidad Complutense, 28040 Madrid (Spain); Stolte, S., E-mail: s.stolte@vu.nl [Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012 (China)

    2016-06-14

    The effect of orientation of the NO(X) bond axis prior to rotationally inelastic collisions with Ar has been investigated experimentally and theoretically. A modification to conventional velocity-map imaging ion optics is described, which allows the orientation of hexapole state-selected NO(X) using a static electric field, followed by velocity map imaging of the resonantly ionized scattered products. Bond orientation resolved differential cross sections are measured experimentally for a series of spin-orbit conserving transitions and compared with quantum mechanical calculations. The agreement between experimental results and those from quantum mechanical calculations is generally good. Parity pairs, which have previously been observed in collisions of unpolarized NO with various rare gases, are not observed due to the coherent superposition of the two j = 1/2, Ω = 1/2 Λ-doublet levels in the orienting field. The normalized difference differential cross sections are found to depend predominantly on the final rotational state, and are not very sensitive to the final Λ-doublet level. The differential steric effect has also been investigated theoretically, by means of quantum mechanical and classical calculations. Classically, the differential steric effect can be understood by considering the steric requirement for different types of trajectories that contribute to different regions of the differential cross section. However, classical effects cannot account quantitatively for the differential steric asymmetry observed in NO(X) + Ar collisions, which reflects quantum interference from scattering at either end of the molecule. This quantum interference effect is dominated by the repulsive region of the potential.

  18. 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

  19. Effects of feed loading on nitrogen balances and fish performance in replicated recirculating aquaculture systems

    DEFF Research Database (Denmark)

    Pedersen, Lars-Flemming; Suhr, Karin Isabel; Dalsgaard, Anne Johanne Tang

    2012-01-01

    This study investigated the effects of applying four fixed feed loadings to three replicated recirculating aquaculture systems (RAS) on water quality changes, nitrogenous balances and growth performance of rainbow trout (Oncorhynchus mykiss).Feed loadings ranged from 1.6 to 6.3kgfeed/m3 make-up...... water, with a constant make-up water renewal of 4.7% of total water volume per day in all twelve RAS. Fish densities ranged from 14 to 92kg/m3 during the prolonged trial of 10weeks. Selected water quality parameters were measured during two intensive sampling campaigns, evaluating biofilter...

  20. Effects of a Dual-Loop Exhaust Gas Recirculation System and Variable Nozzle Turbine Control on the Operating Parameters of an Automotive Diesel Engine

    Directory of Open Access Journals (Sweden)

    Giorgio Zamboni

    2017-01-01

    Full Text Available Reduction of NOX emissions and fuel consumption are the main topics in engine development, forcing the adoption of complex techniques and components, whose interactions have to be clearly understood for proper and reliable operations and management of the whole system. The investigation presented in this paper aimed at the development of integrated control strategies of turbocharging, high pressure (HP and low pressure (LP exhaust gas recirculation (EGR systems for better NOX emissions and fuel consumption, while analyzing their reciprocal influence and the resulting variations of engine quantities. The study was based on an extended experimental program in three part load engine operating conditions. In the paper a comparison of the behavior of the main engine sub-systems (intake and exhaust circuits, turbocharger turbine and compressor, HP and LP EGR loops in a wide range of operating modes is presented and discussed, considering open and closed loop approaches for variable nozzle turbine (VNT control, and showing how these affect engine performance and emissions. The potential of significant decrease in NOX emissions through the integration of HP and LP EGR was confirmed, while a proper VNT management allowed for improved fuel consumption level, if an open loop control scheme is followed. At higher engine speed and load, further actions have to be applied to compensate for observed soot emissions increase.

  1. Activity buildup in the recirculation system of boiling water reactors

    International Nuclear Information System (INIS)

    Grauer, R.

    1987-05-01

    The deposition of activated corrosion products in the recirculation system of boiling water reactors produces increased radiation levels which lead to a corresponding increase in personnel irradiation dose rates during shut down and maintenance. The major part of this dose rate is due to Co-60. Based on a comprehensive literature study concerning this theme, the author has attempted to identify the individual stages of the activity build up and to classify their importance. The following areas are discussed in detail: - the origins of the corrosion products and of Co-59 in the reactor feedwater; - the consolidation of the cobalt in the fuel element crud deposits (activation); - the release and transport of the Co-60; - the build up of Co-60 in the corrosion products of the primary circuit. Existing models for the build up of cirquit radioactivity are discussed and the operating experience from selected reactors are summarized. Finally the state of the art of knowledge concerning the individual stages in the development of the activation build up is depicted. This highlights the existing gaps and thus identifies areas for possible R+D activities. Corrosion chemistry aspects of the cobald build up in the primary cirquit have already been studied on a broad basis and are continuing to be researched in a number of centers. The crystal chemistry of austenitic steel corrosion products poses a number of yet unanswered questions. There are major loopholes associated with an understanding of the activation processes of the cobalt deposited on the fuel elements and in the mass transfer of Co-60. For these processes, the most important influence stems from factors associated with colloid chemistry. In this respect there is ample room for new and original research contributions. It is recommended that sections 8 and 9 of this report should be read as an 'Executive Summary'. (author)

  2. Composite TiO{sub 2}/clays materials for photocatalytic NOx oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Todorova, N.; Giannakopoulou, T.; Karapati, S.; Petridis, D. [Institute of Nanoscience and Nanotechnology, NCSR “Demokritos”, P.O. Box 60037, 153 10, Ag. Paraskevi, Attiki (Greece); Vaimakis, T. [Department of Chemistry, University of Ioannina, P.O. Box 1186, 451 10, Ioannina (Greece); Trapalis, C., E-mail: trapalis@ims.demokritos.gr [Institute of Nanoscience and Nanotechnology, NCSR “Demokritos”, P.O. Box 60037, 153 10, Ag. Paraskevi, Attiki (Greece)

    2014-11-15

    Graphical abstract: - Highlights: • Clays-supported TiO{sub 2} photocatalysts are prepared by simple, scalable method. • Visible light active TiO{sub 2} is incorporated in hydrotalcite, talk and kunipia clays. • The alkali substrates facilitate the NOx adsorption to the photocatalytic surface. • Low-content TiO{sub 2} photocatalysts demonstrated high NOx oxidation activity. • Titania/hydrotalcite photocatalyst exhibited remarkable NOx removal activity. - Abstract: TiO{sub 2} photocatalyst received much attention for air purification applications especially for removal of air pollutants like NOx, VOCs etc. It has been established that the activity of the photocatalyst can be significantly enhanced by its immobilization onto suitable substrates like inorganic minerals, porous silica, hydroxyapatite, adsorbent materials like activated carbon, various co-catalysts such as semiconductors, graphene, reduced graphite oxide, etc. In the present work, photocatalytic composite materials consisted of mineral substrate and TiO{sub 2} in weight ratio 1:1 were manufactured and examined for oxidation and removal of nitric oxides NOx (NO and NO{sub 2}). Commercial titania P25 (Evonik-Degussa) and urea-modified P25 were used as photocatalytically active components. Inorganic minerals, namely kunipia, talk and hydrotalcite were selected as supporting materials due to their layered structure and expected high NOx adsorption capability. Al{sup 3+} and Ca{sup 2+} intercalation was applied in order to improve the dispersion of TiO{sub 2} and its loading into the supporting matrix. The X-ray diffraction analysis and Scanning Electron Microscopy revealed the binary structure of the composites and homogeneous dispersion of the photocatalyst into the substrates. The photocatalytic behavior of the materials in NOx oxidation and removal was investigated under UV and visible light irradiation. The composite materials exhibited superior photocatalytic activity than the bare titania

  3. Exploring the roles of temperature and NOx on ozone production in the Sacramento urban plume

    Science.gov (United States)

    Lafranchi, B. W.; Cohen, R. C.

    2009-12-01

    We investigate the role of temperature and NOx (NOx = NO+NO2) on ozone (O3) production in the Sacramento urban plume over a stretch of seven years (2001-2007) using data collected at UC Blodgett Forest Research Station (a forested site in the Sierra Nevadas about 80 km downwind of Sacramento, CA) and at a series of California Air Resources Board (CARB) sites along the Sacramento-Blodgett transect. The consistent daytime wind patterns between the Central Valley of California and the foothills of the Sierra Nevada mountains permits the assumption of plume transport from downtown Sacramento, over the CARB monitoring sites in the eastern suburbs, and past the Blodgett Forest research site. While NOx emissions are limited primarily to the urban and suburban regions of the transect, biogenic volatile organic compound (VOC) emissions are significant throughout the transect, thus there is a fast transition from VOC-limited to NOx-limited as the plume travels away from the urban center, and we have the opportunity to analyze the differences in ozone production across these two chemical regimes. For this analysis, the Sacramento-Blodgett transect is separated into three segments: urban, suburban, and rural, defined by the locations of selected monitoring sites. Ozone concentrations across each segment are controlled by chemical production (Pchem) and loss (Lchem), deposition to surfaces (Ldep), and mixing with background air (Lmix). At an assumed deposition rate, mixing rate, and background O3 concentration, the net chemical flux of ozone (Pchem - Lchem) can be inferred from differences in ozone concentrations between adjacent monitoring sites. We show that ozone production rates, in general, increase with temperature. We also show that decreases in NOx emissions over the period from 2001-2007 have been effective at reducing ozone production at all points along the transect, but only on days where temperatures are highest. At low temperatures, this decrease is less apparent

  4. NOx Reduction Technology in Diesel Engine Exhaust by the Plasmatron

    International Nuclear Information System (INIS)

    Joa, Sang Beom

    2008-02-01

    completeness of the partial fuel oxidation reaction up to 100%. Nitrogen was found to be the most effective gas for the synthesis gas production by a plasmatron. The preliminary experiments of introducing the reformation products into a diesel engine resulted in ∼25% NOx cut in the exhaust gas flow. A simulation experiment with the pure hydrogen addition to the inlet of a diesel engine showed that both components of the synthesis gas H 2 and CO fed into the engine play significant role in cutting NOx content in the engine's emission. The selective catalytic reduction (SCR) with propylene and decane as reductants in the presence of excess air over (Fe, Co-Pt)/ZSM-5 catalyst was conducted to remove NOx from Diesel exhaust gases. The SO 2 effect and deactivation test over above catalyst were also executed. ZSM-5 supported Co, Pt, Fe mixed oxide catalyst showed about 80% of conversion in the presence of NO. However, the activity was decreased when the catalyst was wash coated onto the ceramic monolith. We found that the deNOx activity over the catalyst was strongly depended on the amount of reductant. Therefore, the amount reductant and how to feed the reductant into the system should be considered as important factors to remove NOx. In order to develop the high removal NOx activity at low temperature and maintain the stable activity at the real exhaust gases condition, metallosilicate and Pt/ZSM-5 catalysts have been used. In case of metallosilicate catalyst, the deNOx activity was low at the oxidation atmospheric condition. When the Pt was ion-exchanged with ZSM-5, the H-form of ZSM-5 catalyst showed high deNOx activity. The effect of reductant type on deNOx activity exhibited that the olefin system provided more higher activity than octane system. The methane conversion observed in the presence of NO and excess O 2 over alumina supported Pt catalyst. In order to improve the activity and durability, the Co metal ion was added. The result showed that the Co-Pt catalyst gave

  5. 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

  6. Reducing NOx Emissions for a 600 MWe Down-Fired Pulverized-Coal Utility Boiler by Applying a Novel Combustion System.

    Science.gov (United States)

    Ma, Lun; Fang, Qingyan; Lv, Dangzhen; Zhang, Cheng; Chen, Yiping; Chen, Gang; Duan, Xuenong; Wang, Xihuan

    2015-11-03

    A novel combustion system was applied to a 600 MWe Foster Wheeler (FW) down-fired pulverized-coal utility boiler to solve high NOx emissions, without causing an obvious increase in the carbon content of fly ash. The unit included moving fuel-lean nozzles from the arches to the front/rear walls and rearranging staged air as well as introducing separated overfire air (SOFA). Numerical simulations were carried out under the original and novel combustion systems to evaluate the performance of combustion and NOx emissions in the furnace. The simulated results were found to be in good agreement with the in situ measurements. The novel combustion system enlarged the recirculation zones below the arches, thereby strengthening the combustion stability considerably. The coal/air downward penetration depth was markedly extended, and the pulverized-coal travel path in the lower furnace significantly increased, which contributed to the burnout degree. The introduction of SOFA resulted in a low-oxygen and strong-reducing atmosphere in the lower furnace region to reduce NOx emissions evidently. The industrial measurements showed that NOx emissions at full load decreased significantly by 50%, from 1501 mg/m3 (O2 at 6%) to 751 mg/m3 (O2 at 6%). The carbon content in the fly ash increased only slightly, from 4.13 to 4.30%.

  7. Calcineurin Aβ regulates NADPH oxidase (Nox) expression and activity via nuclear factor of activated T cells (NFAT) in response to high glucose.

    Science.gov (United States)

    Williams, Clintoria R; Gooch, Jennifer L

    2014-02-21

    Hypertrophy is an adaptive response that enables organs to appropriately meet increased functional demands. Previously, we reported that calcineurin (Cn) is required for glomerular and whole kidney hypertrophy in diabetic rodents (Gooch, J. L., Barnes, J. L., Garcia, S., and Abboud, H. E. (2003). Calcineurin is activated in diabetes and is required for glomerular hypertrophy and ECM accumulation. Am. J. Physiol. Renal Physiol. 284, F144-F154; Reddy, R. N., Knotts, T. L., Roberts, B. R., Molkentin, J. D., Price, S. R., and Gooch, J. L. (2011). Calcineurin Aβ is required for hypertrophy but not matrix expansion in the diabetic kidney. J. Cell Mol. Med. 15, 414-422). Because studies have also implicated the reactive oxygen species-generating enzymes NADPH oxidases (Nox) in diabetic kidney responses, we tested the hypothesis that Nox and Cn cooperate in a common signaling pathway. First, we examined the role of the two main isoforms of Cn in hypertrophic signaling. Using primary kidney cells lacking a catalytic subunit of Cn (CnAα(-/-) or CnAβ(-/-)), we found that high glucose selectively activates CnAβ, whereas CnAα is constitutively active. Furthermore, CnAβ but not CnAα mediates hypertrophy. Next, we found that chronic reactive oxygen species generation in response to high glucose is attenuated in CnAβ(-/-) cells, suggesting that Cn is upstream of Nox. Consistent with this, loss of CnAβ reduces basal expression and blocks high glucose induction of Nox2 and Nox4. Inhibition of nuclear factor of activated T cells (NFAT), a CnAβ-regulated transcription factor, decreases Nox2 and Nox4 expression, whereas NFAT overexpression increases Nox2 and Nox4, indicating that the CnAβ/NFAT pathway modulates Nox. These data reveal that the CnAβ/NFAT pathway regulates Nox and plays an important role in high glucose-mediated hypertrophic responses in the kidney.

  8. 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

  9. NOx from cement production - reduction by primary measures

    DEFF Research Database (Denmark)

    Jensen, Lars Skaarup

    1999-01-01

    cement production processes cement is typically produced by thermally treating a mixture of limestone and clay minerals in kiln systems consisting of a rotary kiln and a calciner. Clinker burning at a temperature of about 1450 °C takes place in the internally fired rotary kiln and calcination, which...... rotary kilns, while NOx formation from fuel-N and reduction of NOx take place in calciners. NOx formation in the rotary kiln is mainly governed by the necessary clinker burning temperature and is not very amenable to control, while net NOx formation in calciners depends strongly on calciner design......, 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...

  10. Commercial introduction of the Advanced NOxTECH system

    Energy Technology Data Exchange (ETDEWEB)

    Sudduth, B.C. [NOxTECH, Inc., Irvine, CA (United States)

    1997-12-31

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

  11. Experimental studies of impact of exhaust gas recirculation on the ...

    African Journals Online (AJOL)

    This paper considers the problem of reducing the nitrogen oxides emissions in exhaust gases (EG) of diesel engine by exhaust gas recirculation (EGR). Based on the carried out study the influence of EGR on technical-and-economic and environmental performance of a diesel engine was found as well as main directions of ...

  12. The benefits of flue gas recirculation in waste incineration.

    Science.gov (United States)

    Liuzzo, Giuseppe; Verdone, Nicola; Bravi, Marco

    2007-01-01

    Flue gas recirculation in the incinerator combustion chamber is an operative technique that offers substantial benefits in managing waste incineration. The advantages that can be obtained are both economic and environmental and are determined by the low flow rate of fumes actually emitted if compared to the flue gas released when recirculation is not conducted. Simulations of two incineration processes, with and without flue gas recirculation, have been carried out by using a commercial flowsheeting simulator. The results of the simulations demonstrate that, from an economic point of view, the proposed technique permits a greater level of energy recovery (up to +3%) and, at the same time, lower investment costs as far as the equipment and machinery constituting the air pollution control section of the plant are concerned. At equal treatment system efficiencies, the environmental benefits stem from the decrease in the emission of atmospheric pollutants. Throughout the paper reference is made to the EC legislation in the field of environmental protection, thus ensuring the general validity in the EU of the foundations laid and conclusions drawn henceforth. A numerical example concerning mercury emission quantifies the reported considerations and illustrates that flue gas recirculation reduces emission of this pollutant by 50%.

  13. Recirculating steam generator operation at very low power

    International Nuclear Information System (INIS)

    Holcblat, A.

    2001-01-01

    The behaviour of recirculating SG's at very low power has been thoroughly investigated by laboratory and on-site tests as well as numerical simulations. A special experimental program dedicated to recirculation threshold determination has been performed on the Freon SG mock-up CLOTAIRE. These laboratory data are completed with transients of feedwater injections at hot stand-by on two instrumented SG's, one boiler type SG and one economizer type SG. The phenomena are different on both types. In boiler SG's, the SG behaves like a U-tube and recirculation stops around 2% load at stand-by temperature and water level. In economizer SG's, the presence of 2 separate down-comers and a divider plate inside the tube bundle allows a recirculation loop by-passing the separators. The mixing of saturated and cold water induced by this loop limits down-comer cooling and thus alleviates the thermal load on the tube sheet. These tests were used to validate the SG transient analysis 1-D code ANETH. (author)

  14. Influence of recirculation rate on the performance of a combined ...

    African Journals Online (AJOL)

    The objective of this study was to evaluate a combined anaerobic-aerobic upflow fixed-bed reactor with liquid phase recirculation for the removal of nitrogen and organic matter from poultry slaughterhouse wastewater. The reactor performance was evaluated with a hydraulic retention time (HRT) of 11 h and three different ...

  15. Economic Feasibility of Recirculating Aquaculture Systems in Pangasius Farming

    NARCIS (Netherlands)

    Pham, T.A.N.; Gielen-Meuwissen, M.P.M.; Le, T.C.; Verreth, J.A.J.; Bosma, R.H.; Oude Lansink, A.G.J.M.

    2016-01-01

    This study aims to analyze the economic feasibility of recirculating aquaculture systems (RAS) in pangasius farming in Vietnam. The study uses a capital budgeting approach and accounts for uncertainty in key parameters. Stochastic simulation is used to simulate the economic performance of medium and

  16. Numerical analysis and control of the recirculation bubble strength ...

    African Journals Online (AJOL)

    Numerical investigation of the turbulent jet flows, both central and annular type of jets has been carried out with the introduction of swirl at the inlet using the modified κ −ε model. It was observed that the recirculation bubble generated by the central jet without swirl diminishes in size due to increase in swirl number, while in ...

  17. Constrained control of a once-through boiler with recirculation

    DEFF Research Database (Denmark)

    Trangbæk, K

    2008-01-01

    There is an increasing need to operate power plants at low load for longer periods of time. When a once-through boiler operates at a sufficiently low load, recirculation is introduced, significantly altering the control structure. This paper illustrates the possibilities for using constrained con...

  18. Modeling Tar Recirculation in Biomass Fluidized Bed Gasification

    NARCIS (Netherlands)

    Heineken, Wolfram; De la Cuesta de Cal, Daniel; Zobel, Nico

    2016-01-01

    A biomass gasification model is proposed and applied to investigate the benefits of tar recirculation within a gasification plant. In the model, tar is represented by the four species phenol, toluene, naphthalene, and benzene. The model is spatially one-dimensional, assuming plug flow for the

  19. Composite TiO2/clays materials for photocatalytic NOx oxidation

    Science.gov (United States)

    Todorova, N.; Giannakopoulou, T.; Karapati, S.; Petridis, D.; Vaimakis, T.; Trapalis, C.

    2014-11-01

    TiO2 photocatalyst received much attention for air purification applications especially for removal of air pollutants like NOx, VOCs etc. It has been established that the activity of the photocatalyst can be significantly enhanced by its immobilization onto suitable substrates like inorganic minerals, porous silica, hydroxyapatite, adsorbent materials like activated carbon, various co-catalysts such as semiconductors, graphene, reduced graphite oxide, etc. In the present work, photocatalytic composite materials consisted of mineral substrate and TiO2 in weight ratio 1:1 were manufactured and examined for oxidation and removal of nitric oxides NOx (NO and NO2). Commercial titania P25 (Evonik-Degussa) and urea-modified P25 were used as photocatalytically active components. Inorganic minerals, namely kunipia, talk and hydrotalcite were selected as supporting materials due to their layered structure and expected high NOx adsorption capability. Al3+ and Ca2+ intercalation was applied in order to improve the dispersion of TiO2 and its loading into the supporting matrix. The X-ray diffraction analysis and Scanning Electron Microscopy revealed the binary structure of the composites and homogeneous dispersion of the photocatalyst into the substrates. The photocatalytic behavior of the materials in NOx oxidation and removal was investigated under UV and visible light irradiation. The composite materials exhibited superior photocatalytic activity than the bare titania under both types of irradiation. Significant visible light activity was recorded for the composites containing urea-modified titania that was accredited to the N-doping of the semiconductor. Among the different substrates, the hydrotalcite caused highest increase in the NOx removal, while among the intercalation ions the Ca2+ was more efficient. The results were related to the improved dispersion of the TiO2 and the synergetic activity of the substrates as NOx adsorbers.

  20. Impact assessment of concentrate recirculation on the landfill gas production

    Directory of Open Access Journals (Sweden)

    Džolev Nikola M.

    2016-01-01

    Full Text Available This paper explores the impact of concentrate recirculation, as a product of leachate treated by reverse osmosis plant, on the production of landfill gas at the real-scale landfill for municipal solid waste. In an effort to come up with results experimental measurements were carried out at the landfill in Bijeljina. All measurements performed, were divided into 3 groups. The aims of two groups of measurement were to determine landfill gas and methane yield from concentrate and leachate in laboratory conditions (1st group and to find out concentrations of oxidizing matters (COD and BOD5 present in leachate and concentrate at different points of treatment as well as its variability over the time (2nd group which could be used to calculate the potential of landfill gas and methane generation from concentrate by recirculation, theoretically. 3rd group of measurements, carried out in parallel, have goal to determine the quality and quantity of the collected landfill gas at wells throughout the landfill. The results of analysis carried out in this experimental research show the clear evidence of concentrate recirculation impact on methane production by increasing the landfill gas flow, as well as its concentration within the landfill gas composition, at the nearby well. Although results indicated relatively high impact of concentrate recirculation on landfill gas production, comparing to its theoretical potential, the influence on the landfill at whole, is negligible, due to relatively low volumes in recirculation with respect to its size and objectively low potential given by organic matter present in concentrate.

  1. Supported Metal Zeolites as Environmental Catalysts for Reduction of NOx Molecules

    International Nuclear Information System (INIS)

    May Nwe Win; Tin Tin Aye; Kyaw Myo Naing; Nyunt Wynn; Maung Maung Htay

    2005-09-01

    The NOx contamination of air is a major pollutant due to its reaction with the volatile organic compounds, which give rise to ground level (tropospheric) ozone. It is a conventional fact that NOx are one of the major components of car exhaust. In view of that fact, to sustain the tropospheric ozone is to reduce the amount of NOx in the air. Therefore, this paper is concerned with the catalytic activity of Fe-loaded zeolite and Cu-loaded zeolite used to decompose NIOx by SCR (selective catalytic reduction) reaction with very high activity have been studied. Their preparations, characterization by XRD, FT-IR and SEM were also studied. Fe and Cu containig were prepared by soild state ion-exchange method under ambient presure and at the temperature of 600C for 4 hours. From this study, selective catalytic reduction rection was observed, showing about 87% conversion of the NOx molecule with the corresponding optimum amount of catalyst (1.0+-0.5)g working under the reactor space volume of 30cm3 at ambient temperature (30-32)C

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

    Science.gov (United States)

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

    2016-06-07

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

  3. 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.

  4. Corrosion products, activity transport and deposition in boiling water reactor recirculation systems

    International Nuclear Information System (INIS)

    Alder, H.P.; Buckley, D.; Grauer, R.; Wiedemann, K.H.

    1989-09-01

    The deposition of activated corrosion products in the recirculation loops of Boiling Water Reactors produces increased radiation levels which lead to a corresponding increase in personnel radiation dose during shut down and maintenance. The major part of this dose rate is due to cobalt-60. The following areas are discussed in detail: - the origins of the corrosion products and of cobalt-59 in the reactor feedwaters, - the consolidation of the cobalt in the fuel pin deposits (activation), - the release and transport of cobalt-60, - the build-up of cobalt-60 in the corrosion products in the recirculation loops. Existing models of the build-up of circuit radioactivity are discussed and the operating experiences from selected reactors are summarised. Corrosion chemistry aspects of the cobalt build-up in the primary circuit have already been studied on a broad basis and are continuing to be researched in a number of centers. The crystal chemistry of chromium-nickel steel corrosion products poses a number of yet unanswered questions. There are major loopholes associated with the understanding of activation processes of cobalt deposited on the fuel pins and in the mass transfer of cobalt-60. For these processes, the most important influence stems from factors associated with colloid chemistry. Accumulation of data from different BWRs contributes little to the understanding of the activity build-up. However, there are examples that the problem of activity build-up can be kept under control. Although many details for a quantitative understanding are still missing, the most important correlations are visible. The activity build-up in the BWR recirculation systems cannot be kept low by a single measure. Rather a whole series of measures is necessary, which influences not only cobalt-60 deposition but also plant and operation costs. (author) 26 figs., 13 tabs., 90 refs

  5. Top-down NOX Emissions of European Cities Derived from Modelled and Spaceborne Tropospheric NO2 Columns

    Science.gov (United States)

    Verstraeten, W. W.; Boersma, K. F.; Douros, J.; Williams, J. E.; Eskes, H.; Delcloo, A. W.

    2017-12-01

    High nitrogen oxides (NOX = NO + NO2) concentrations near the surface impact humans and ecosystems badly and play a key role in tropospheric chemistry. NO2 is an important precursor of tropospheric ozone (O3) which in turn affects the production of the hydroxyl radical controlling the chemical lifetime of key atmospheric pollutants and reactive greenhouse gases. Combustion from industrial, traffic and household activities in large and densely populated urban areas result in high NOX emissions. Accurate mapping of these emissions is essential but hard to do since reported emissions factors may differ from real-time emissions in order of magnitude. Modelled NO2 levels and lifetimes also have large associated uncertainties and overestimation in the chemical lifetime which may mask missing NOX chemistry in current chemistry transport models (CTM's). The simultaneously estimation of both the NO2 lifetime and as well as the concentrations by applying the Exponentially Modified Gaussian (EMG) method on tropospheric NO2 columns lines densities should improve the surface NOX emission estimates. Here we evaluate if the EMG methodology applied on the tropospheric NO2 columns simulated by the LOTOS-EUROS (Long Term Ozone Simulation-European Ozone Simulation) CTM can reproduce the NOX emissions used as model input. First we process both the modelled tropospheric NO2 columns for the period April-September 2013 for 21 selected European urban areas under windy conditions (averaged vertical wind speeds between surface and 500 m from ECMWF > 2 m s-1) as well as the accompanying OMI (Ozone Monitoring Instrument) data providing us with real-time observation-based estimates of midday NO2 columns. Then we compare the top-down derived surface NOX emissions with the 2011 MACC-III emission inventory, used in the CTM as input to simulate the NO2 columns. For cities where NOX emissions can be assumed as originating from one large source good agreement is found between the top-down derived

  6. 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

  7. Numerical simulation of flow in De-NOx catalyst honeycomb with NOx reduction reaction

    Energy Technology Data Exchange (ETDEWEB)

    Tanno, K.; Makino, H. [Electric Power Industry, Kanagawa (Japan). Energy Engineering Research Lab.; Kurose, R.; Komori, S. [Kyoto Univ. (Japan). Dept. of Mechanical Engineering and Science

    2013-07-01

    The effect of flow behavior in a De-NOx honeycomb with NOx reduction reaction is investigated by direct numerical simulation (DNS). As the inlet flow, fully developed turbulent or laminar flow is given. The results show that the surface reaction is strongly affected by inner flow behavior. The surface reaction rate for the turbulent flow is higher than that for the laminar flow. This is due to the difference of inner flow behavior that the diffusion of NOx in the vicinity of the wall is dominated only by molecular diffusion for the laminar flow, whereas it is enhanced by turbulent motions for the turbulent flow. Moreover, surface reaction is suppressed towards downstream even though inlet flow is turbulent. This is due to the flow transition from turbulent to laminar.

  8. Central recirculation zone analysis in an unconfined tangential swirl burner with varying degrees of premixing

    Energy Technology Data Exchange (ETDEWEB)

    Valera-Medina, A. [CIATEQ, Parque Industrial Bernardo Quintana, Turbomachinery Department, Queretaro (Mexico); Syred, N.; Kay, P.; Griffiths, A. [Cardiff University, School of Engineering, Cardiff, Wales (United Kingdom)

    2011-06-15

    Swirl-stabilised combustion is one of the most widely used techniques for flame stabilisation, uses ranging from gas turbine combustors to pulverised coal-fired power stations. In gas turbines, lean premixed systems are of especial importance, giving the ability to produce low NOx systems coupled with wide stability limits. The common element is the swirl burner, which depends on the generation of an aerodynamically formed central recirculation zone (CRZ) and which serves to recycle heat and active chemical species to the root of the flame as well as providing low-velocity regions where the flame speed can match the local flow velocity. Enhanced mixing in and around the CRZ is another beneficial feature. The structure of the CRZ and hence that of the associated flames, stabilisation and mixing processes have shown to be extremely complex, three-dimensional and time dependent. The characteristics of the CRZ depend very strongly on the level of swirl (swirl number), burner configuration, type of flow expansion, Reynolds number (i.e. flowrate) and equivalence ratio. Although numerical methods have had some success when compared to experimental results, the models still have difficulties at medium to high swirl levels, with complex geometries and varied equivalence ratios. This study thus focuses on experimental results obtained to characterise the CRZ formed under varied combustion conditions with different geometries and some variation of swirl number in a generic swirl burner. CRZ behaviour has similarities to the equivalent isothermal state, but is strongly dependent on equivalence ratio, with interesting effects occurring with a high-velocity fuel injector. Partial premixing and combustion cause more substantive changes to the CRZ than pure diffusive combustion. (orig.)

  9. Effects of exhaust gas recirculation in diesel engines featuring late PCCI type combustion strategies

    International Nuclear Information System (INIS)

    D’Ambrosio, S.; Ferrari, A.

    2015-01-01

    Highlights: • The effects that a high EGR rate can have on PCCI type combustion strategies have been analyzed. • The dependence of engine emissions and combustion noise on EGR has been addressed. • The time histories of the main in-cylinder variables have been plotted for different EGR rates. - Abstract: The influence of exhaust gas recirculation (EGR) has been analyzed considering experimental results obtained from a Euro 5 diesel engine calibrated with an optimized pilot-main double injection strategy. The engine features a late premixed charge compression ignition (PCCI) type combustion mode. Different steady-state key-points that are representative of the engine application in a passenger car over the New European Driving Cycle (NEDC) have been studied. The engine was fully instrumented to obtain a complete overview of the most important variables. The pressure time history in the combustion chamber has been measured to perform calculations with single and three-zone combustion diagnostic models. These models allow the in-cylinder emissions and the temperature of the burned and unburned zones to be evaluated as functions of the crankshaft angle. The EGR mass fraction was experimentally varied within the 0–50% range. The results of the investigation have shown the influence that high EGR rates can have on intake and exhaust temperatures, in-cylinder pressure and heat release rate time histories, engine-out emissions (CO, HC, NO_x, soot), brake specific fuel consumption and combustion noise for a PCCI type combustion strategy. The outputs of the diagnostic models have been used to conduct a detailed analysis of the cause-and-effect relationships between the EGR rate variations and the engine performance. Finally, the effect of the EGR on the cycle-to-cycle variability of the engine torque has been experimentally investigated.

  10. Nox4 Is Dispensable for Exercise Induced Muscle Fibre Switch.

    Directory of Open Access Journals (Sweden)

    Juri Vogel

    Full Text Available By producing H2O2, the NADPH oxidase Nox4 is involved in differentiation of mesenchymal cells. Exercise alters the composition of slow and fast twitch fibres in skeletal. Here we hypothesized that Nox4 contributes to exercise-induced adaptation such as changes in muscle metabolism or muscle fibre specification and studied this in wildtype and Nox4-/- mice.Exercise, as induced by voluntary running in a running wheel or forced running on a treadmill induced a switch from fast twitch to intermediate fibres. However the induced muscle fibre switch was similar between Nox4-/- and wildtype mice. The same held true for exercise-induced expression of PGC1α or AMPK activation. Both are increased in response to exercise, but with no difference was observed between wildtype and Nox4-/- mice.Thus, exercise-induced muscle fibre switch is Nox4-independent.

  11. 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...

  12. 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...

  13. 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...

  14. A dented LH2 recirculation line is removed from Discovery

    Science.gov (United States)

    1999-01-01

    In the Payload Changeout Room, Launch Pad 39B, United Space Alliance and NASA workers look at the replacement main propulsion system liquid hydrogen recirculation line (left) to be installed in Shuttle Discovery's aft compartment. At right is the dented line that has been removed. The 12-inch-long dent was discovered during routine aft compartment inspections Tuesday, Dec. 7. The line recirculates hydrogen from the Shuttle main engines back to the external tank during prelaunch engine conditioning. The line is being replaced and managers expect the replacement work to take about 3 days, followed by system retests and final aft compartment close-outs. Preliminary assessments reflect a launch date of Space Shuttle Discovery on mission STS-103 no earlier than Dec. 16. STS-103 is the third servicing mission for the Hubble Space Telescope.

  15. A replacement LH2 recirculation line before installation in Discovery

    Science.gov (United States)

    1999-01-01

    A spare four-inch diameter LH2 recirculation line (shown in photo) will be used to replace a damaged LH2 line in the orbiter Discovery. The line recirculates hydrogen from the Shuttle main engines back to the external tank during prelaunch engine conditioning. Workers noted a dent in the line during routine aft compartment inspections Tuesday, Dec. 7. The dent measures 12 inches long and about =-inch deep. Managers expect the replacement work to take about 3 days, followed by system retests and final aft compartment close-outs. Preliminary assessments reflect a launch date of Space Shuttle Discovery on mission STS-103 no earlier than Dec. 16. STS-103 is the third servicing mission for the Hubble Space Telescope.

  16. Engine with exhaust gas recirculation system and variable geometry turbocharger

    Science.gov (United States)

    Keating, Edward J.

    2015-11-03

    An engine assembly includes an intake assembly, an internal combustion engine defining a plurality of cylinders and configured to combust a fuel and produce exhaust gas, and an exhaust assembly in fluid communication with a first subset of the plurality of cylinders. Each of the plurality of cylinders are provided in fluid communication with the intake assembly. The exhaust assembly is provided in fluid communication with a first subset of the plurality of cylinders, and a dedicated exhaust gas recirculation system in fluid communication with both a second subset of the plurality of cylinders and with the intake assembly. The dedicated exhaust gas recirculation system is configured to route all of the exhaust gas from the second subset of the plurality of cylinders to the intake assembly. Finally, the engine assembly includes a turbocharger having a variable geometry turbine in fluid communication with the exhaust assembly.

  17. Recirculating electric air filter for use in confined spaces

    International Nuclear Information System (INIS)

    Bergman, W.; Biermann, A.; Kuhl, W.

    1985-01-01

    We have developed recirculating electric air filters for use in confined spaces where the existing ventilation system is not adequate for removing suspended particles. Two experimental filters were built and evaluated, both of which consisted of a cylindrical cartridge filter fitted over an air blower. In one design the cylindrical cartridge is a disposable unit with the electrodes and filter medium built as an integrated unit. The second design has a cylindrical cartridge that can be easily disassembled to allow replacement of the filter medium. Both designs were evaluated in a 354-ft 3 test cell using NaCl aerosols. The second design was installed and evaluated in a chamber where highly radioactive 238 PuO 2 powder is formed into pellets. We have derived equations that describe the theory of recirculating air filters. The predicted performance compares well with experimental measurements under controlled conditions. 2 refs., 7 figs., 1 tab. (DT)

  18. Digital feedwater and recirculation flow control for GPUN Oyster Creek

    International Nuclear Information System (INIS)

    Burjorjee, D.; Gan, B.

    1992-01-01

    This paper describes the digital system for feedwater and recirculation control that GPU Nuclear will be installing at Oyster Creek during its next outage - expected circa December 1992. The replacement was motivated by considerations of reliability and obsolescence - the analog equipment was aging and reaching the end of its useful life. The new system uses Atomic Energy of Canada Ltd.'s software platform running on dual, redundant, industrial-grade 386 computers with opto-isolated field input/output (I/O) accessed through a parallel bus. The feedwater controller controls three main feed regulating valves, two low flow regulating valves, and two block valves. The recirculation controller drives the five scoop positioners of the hydraulic couplers. The system also drives contacts that lock up the actuators on detecting an open circuit in their current loops

  19. Pelletron-based MeV-range electron beam recirculation

    CERN Document Server

    Crawford, A C; Sharapa, A N; Shemyakin, A

    1999-01-01

    In this paper we describe the successful recirculation of a DC electron beam at energies 1-1.5 MeV and currents up to 0.7 A with typical relative losses of 5-20x10 sup - sup 6. Currents of 200 mA were maintained for periods of up to five hours without a single breakdown. We found that the aperture-limiting diaphragm in the gun anode significantly increased the stability of the recirculation. We also found that the stability depended strongly on vacuum pressure in the beamline. The performance of the collector with transverse magnetic fields was found to be adequate for beam currents up to 0.6 A, which is in agreement with our low-energy bench test results. (author)

  20. A portable gas recirculation unit for gaseous detectors

    Science.gov (United States)

    Guida, R.; Mandelli, B.

    2017-10-01

    The use of greenhouse gases (usually C2H2F4, CF4 and SF6) is sometimes necessary to achieve the required performance for some gaseous detectors. The consumption of these gases in the LHC systems is reduced by recycling the gas mixture thanks to a complex gas recirculation system. Beyond greenhouse gas consumption due to LHC systems, a considerable contribution is generated by setups used for LHC detector upgrade projects, R&D activities, detector quality assurance or longevity tests. In order to minimise this emission, a new flexible and portable gas recirculation unit has been developed. Thanks to its low price, flexibility and user-friendly operation it can be easily adapted for the different types of detector systems and set-ups.

  1. A numerical study on extinction and NOx formation in nonpremixed flames with syngas fuel

    KAUST Repository

    Chun, Kangwoo; Chung, Hun J.; Chung, Suk-Ho; Choi, Jaehyuk

    2011-01-01

    The flame structure, extinction, and NOx emission characteristics of syngas/air nonpremixed flames, have been investigated numerically. The extinction stretch rate increased with the increase in the hydrogen proportion in the syngas and with lower fuel dilution and higher initial temperature. It also increased with pressure, except for the case of highly diluted fuel at high pressure. The maximum temperature and the emission index of nitric oxides (EINOx) also increased in aforementioned conditions. The EINOx decreased with stretch rate in general, while the decreasing rate was found to be somewhat different between the cases of N2 and CO2 dilutions. The reaction paths of NOx formation were analyzed and represented as NO reaction path diagram. The increase in N radical resulted in larger NOx production at high initial temperature and pressure. As the pressure increases, EINOx increases slower due to the third-body recombination. The thermal NO mechanism is weakened for high dilution cases and non-thermal mechanisms prevail. The combustion conditions achieving higher extinction stretch rate can be lead to more NOx emission, therefore that the selection of optimum operation range is needed in syngas combustion. © 2011 The Korean Society of Mechanical Engineers and Springer-Verlag Berlin Heidelberg.

  2. A numerical study on extinction and NOx formation in nonpremixed flames with syngas fuel

    KAUST Repository

    Chun, Kangwoo

    2011-11-01

    The flame structure, extinction, and NOx emission characteristics of syngas/air nonpremixed flames, have been investigated numerically. The extinction stretch rate increased with the increase in the hydrogen proportion in the syngas and with lower fuel dilution and higher initial temperature. It also increased with pressure, except for the case of highly diluted fuel at high pressure. The maximum temperature and the emission index of nitric oxides (EINOx) also increased in aforementioned conditions. The EINOx decreased with stretch rate in general, while the decreasing rate was found to be somewhat different between the cases of N2 and CO2 dilutions. The reaction paths of NOx formation were analyzed and represented as NO reaction path diagram. The increase in N radical resulted in larger NOx production at high initial temperature and pressure. As the pressure increases, EINOx increases slower due to the third-body recombination. The thermal NO mechanism is weakened for high dilution cases and non-thermal mechanisms prevail. The combustion conditions achieving higher extinction stretch rate can be lead to more NOx emission, therefore that the selection of optimum operation range is needed in syngas combustion. © 2011 The Korean Society of Mechanical Engineers and Springer-Verlag Berlin Heidelberg.

  3. Dietary carbohydrates and denitrification in recirculating aquaculture systems

    OpenAIRE

    Meriac, A.

    2014-01-01

    Due to overfishing of global fish stocks and increasing fish meal prices, plant ingredients are being increasingly used as an alternative source of protein in fish feeds. However, the inclusion of unpurified plant ingredients will also increase the content of fibers in feeds. Fibers are nearly indigestible and will therefore increase solid waste production in aquaculture. This solid waste can be used to as a carbon source for denitrification to control nitrate levels in recirculating aquacul...

  4. Cost Characteristics of the African Catfish Culture in Recirculating ...

    African Journals Online (AJOL)

    Cost Characteristics of the African Catfish Culture in Recirculating Production Facilities in Ibadan, Oyo State, Nigeria. ... Food Conversion Ratio also ranged from 0.60–0.78 for fingerlings, 1.01-‐ 2.08 for juveniles and 1.15-‐1.68 for grow out system. In all cases, variable cost accounts for more than 75% of total cost.

  5. Tracking studies in eRHIC energy-recovery recirculator

    Energy Technology Data Exchange (ETDEWEB)

    Meot, F. [Brookhaven National Lab. (BNL), Upton, NY (United States); Brooks, S. [Brookhaven National Lab. (BNL), Upton, NY (United States); Ptitsyn, V. [Brookhaven National Lab. (BNL), Upton, NY (United States); Trbojevic, D. [Brookhaven National Lab. (BNL), Upton, NY (United States); Tsoupas, N. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2015-07-13

    Beam and polarization tracking studies in eRHIC energy recovery electron recirculator are presented, based on a very preliminary design of the FFAG lattice. These simulations provide examples of some of the beam and spin optics aspects of the linear FFAG lattice concept and its application in eRHIC, they provide code benchmarking for synchrotron radiation and spin diffusion in addition, and pave the way towards end-to-end 6-D(phasespace)+3D(spin) tracking simulations.

  6. Maintenance of reactor recirculation pumps [Paper No.: II-1

    International Nuclear Information System (INIS)

    Ansari, M.A.; Bhat, K.P.

    1981-01-01

    At Tarapur Atomic Power Station (TAPS), two reactor recirculation pumps are provided, one each for the two reactor units. The performance of pumps has been uniformly good; however, leakage through the cartridge type, two stage, mechanical seals which are installed on these pumps was encountered on few occasions. The paper describes the leakage problems, identification of certain design deficiencies and rectification carried out at TAPS for overcoming these problems. (author)

  7. Study on the Conversion of Fuel Nitrogen Into NOx

    Directory of Open Access Journals (Sweden)

    Raminta Plečkaitienė

    2011-12-01

    Full Text Available The aim of this work is to investigate NOx regularities combusting fuels having high concentration of nitrogen and to develop methods that will reduce the conversion of fuel nitrogen into NOx. There are three solutions to reducing NOx concentration: the combustion of fuel mixing it with other types of “clean” fuel containing small amounts of nitrogen, laundering fuel and the combustion of fuel using carbon additives. These solutions can help with reducing the amount of nitrogen in the wood waste of furniture by about 30% by washing fuel with water. Therefore, NOx value may decrease by about 35%.Article in Lithuanian

  8. NoxO1 Controls Proliferation of Colon Epithelial Cells

    Directory of Open Access Journals (Sweden)

    Franziska Moll

    2018-05-01

    Full Text Available AimReactive oxygen species (ROS produced by enzymes of the NADPH oxidase family serve as second messengers for cellular signaling. Processes such as differentiation and proliferation are regulated by NADPH oxidases. In the intestine, due to the exceedingly fast and constant renewal of the epithelium both processes have to be highly controlled and balanced. Nox1 is the major NADPH oxidase expressed in the gut, and its function is regulated by cytosolic subunits such as NoxO1. We hypothesize that the NoxO1-controlled activity of Nox1 contributes to a proper epithelial homeostasis and renewal in the gut.ResultsNoxO1 is highly expressed in the colon. Knockout of NoxO1 reduces the production of superoxide in colon crypts and is not subsidized by an elevated expression of its homolog p47phox. Knockout of NoxO1 increases the proliferative capacity and prevents apoptosis of colon epithelial cells. In mouse models of dextran sulfate sodium (DSS-induced colitis and azoxymethane/DSS induced colon cancer, NoxO1 has a protective role and may influence the population of natural killer cells.ConclusionNoxO1 affects colon epithelium homeostasis and prevents inflammation.

  9. Seismic proving test of BWR primary loop recirculation system

    International Nuclear Information System (INIS)

    Sato, H.; Shigeta, M.; Karasawa, Y.

    1987-01-01

    The seismic proving test of BWR Primary Loop Recirculation system is the second test to use the large-scale, high-performance vibration table of Tadotsu Engineering Laboratory. The purpose of this test is to prove the seismic reliability of the primary loop recirculation system (PLR), one of the most important safety components in the BWR nuclear plants, and also to confirm the adequacy of seismic analysis method used in the current seismic design. To achieve the purpose, the test was conducted under conditions and scale as near as possible to actual systems. The strength proving test was carried out with the test model mounted on the vibration table in consideration of basic design earthquake ground motions and other conditions to confirm the soundness of structure and the strength against earthquakes. Detailed analysis and analytic evaluation of the data obtained from the test was conducted to confirm the adequacy of the seismic analysis method and earthquake response analysis method used in the current seismic design. Then, on the basis of the results obtained, the seismic safety and reliability of BWR primary loop recirculation of the actual plants was fully evaluated

  10. Thermodynamics of premixed combustion in a heat recirculating micro combustor

    International Nuclear Information System (INIS)

    Rana, Uttam; Chakraborty, Suman; Som, S.K.

    2014-01-01

    A thermodynamic model has been developed to evaluate exergy transfer and its destruction in the process of premixed combustion in a heat recirculating micro combustor. Exergy destruction caused by process irreversibilities is characterized by entropy generation in the process. The entropy transport equation along with the solution of temperature and species concentration fields in the wake of flame sheet assumptions have been used to determine the different components of entropy generation. The role of thermal conductivity and thickness of combustor wall, and Peclet number on transfer and destruction rate of exergy is depicted in the process of flame stabilization via heat recirculation. The entropy generations due to gas phase heat conduction and chemical reaction are identified as the major sources of exergy destruction. The total irreversibility in pre-flame region is confined only within a small distance upstream of the flame. It has been observed that the local volumetric entropy generation is higher near the axis than that near the combustor wall. The second law efficiency is almost invariant with heat loss from the combustor, Peclet number, and thermal conductivity and thickness of combustor wall. - Highlights: • Irreversibility in the combustor is mainly due to conduction and chemical reaction. • Entropy generation near the axis is higher compared to that near the wall. • Heat recirculation and process irreversibility decrease with heat loss. • The second law efficiency is almost independent of Peclet number. • Second law efficiency is almost independent of wall thermal conductivity

  11. Combined production of fish and plants in recirculating water

    Energy Technology Data Exchange (ETDEWEB)

    Naegel, L.C.A.

    1977-01-01

    A pilot plant of ca 2000 l of recirculating fresh water for intensive fish production was constructed in a controlled-environment greenhouse. The feasibility was examined of using nutrients from fish wastewater, mainly oxidized nitrogenous compounds, for plant production, combined with an activated sludge system for water purification. The reduction of nitrates, formed during the extended aeration process by nitrifying bacteria, was not sufficient by higher plants and unicellular algae alone to reduce the nitrate concentration in our system significantly. An additional microbial denitrification step had to be included to effect maximal decrease in nitrogenous compounds. For fish culture in the pilot plant Tilapia mossambica and Cyprinus carpio were chosen as experimental fishes. Both fish species showed significant weight increases during the course of the experiment. Ice-lettuce and tomatoes were tested both in recirculating water and in batch culture. The unicellular algae Scenedesmus spp. were grown in a non-sterile batch culture. All plants grew well in the wastewater without additional nutrients. Determination of the physical and chemical parameters for optimum water purification, the most suitable ratio of denitrification by plants and by microorganisms, and the most favourable fish and plant species for combined culture in recirculating water are important and of current interest in view of the increasing demand for clean, fresh water, and the pressing need to find new ways of producing protein for human nutrition under prevailing conditions of an exponentially expanding world population.

  12. Investigation of flashing de-aeration with and without recirculation

    International Nuclear Information System (INIS)

    Kjellstroem, B.; Toecksberg, B.

    1977-06-01

    A series of experiments with flashing de-areation has been carried out at the institute of Thermal Energytechnology of the Royal Institute of Technology in Stockholm. The results of the experiments with flashing de-areation without recirculation of the condensate show very low contents of dissolved oxygen in the de-aerated water. The results indicate that the de-aeration process is independent of the pressure. De-aeration efficiencies over 99 percent were measured. The continued experiments with recirculation of the condensate show a considerably deteriorated de-aeration performance together with a marked pressure dependency. A simple theoretical model has been formulated which explains these results. Comparisons between the experimental data and calculations with this model indicate that a conservative estimation of the oxygen content of the outgoing water can be obtained if the oxygen content of the recirculated condensate is calculated for the partial pressure of noncondensible gases equal to the total pressure in the condensor. It seems also possible to estimate a lower limit for the oxygen content of the outgoing water. The range of oxygen content between those limits is about a factor of 10 for the conditions investigated. Further studies of the uptake of oxygen during condensation seem necessary if a more accurate prediction is desired

  13. 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.

  14. Investigation of Microbunching Instabilities in Modern Recirculating Accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, Cheng [Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States)

    2017-05-21

    Particle accelerators are machines to accelerate and store charged particles, such as electrons or protons, to the energy levels for various scientific applications. A collection of charged particles usually forms a particle beam. There are three basic types of particle accelerators: linear accelerators (linac), storage-ring (or circular) accelerators, and recirculating accelerators. In a linac, particles are accelerated and pass through once along a linear or straight beamline. Storage-ring accelerators propel particles around a circular track and repetitively append the energy to the stored beam. The third type, also the most recent one in chronology, the recirculating accelerator, is designed to accelerate the particle beam in a short section of linac, circulate the beam, and then either continue to accelerate for energy boost or decelerate it for energy recovery. The beam properties of a linac machine are set at best by the initial particle sources. For storage rings, the beam equilibria are instead determined by the overall machine design. The modern recirculating machines share with linacs the advantages to both accelerate and preserve the beam with high beam quality, as well as efficiently reuse the accelerating components. The beamline design in such a machine configuration can however be much more complicated than that of linacs. As modern accelerators push toward the high-brightness or high-intensity frontier by demanding particles in a highly charged bunch (about nano-Coulomb per bunch) to concentrate in an ever-decreasing beam phase space (transverse normalized emittance about 1 μm and relative energy spread of the order of 10^-5 in GeV beam energy), the interaction amongst particles via their self-generated electromagnetic fields can potentially lead to coherent instabilities of the beam and thus pose significant challenges to the machine design and operation. In the past decade and a half, microbunching instability (MBI) has been one of the most

  15. Impact of capillary rise and recirculation on simulated crop yields

    Directory of Open Access Journals (Sweden)

    J. Kroes

    2018-05-01

    Full Text Available Upward soil water flow is a vital supply of water to crops. The purpose of this study is to determine if upward flow and recirculated percolation water can be quantified separately, and to determine the contribution of capillary rise and recirculated water to crop yield and groundwater recharge. Therefore, we performed impact analyses of various soil water flow regimes on grass, maize and potato yields in the Dutch delta. Flow regimes are characterized by soil composition and groundwater depth and derived from a national soil database. The intermittent occurrence of upward flow and its influence on crop growth are simulated with the combined SWAP-WOFOST model using various boundary conditions. Case studies and model experiments are used to illustrate the impact of upward flow on yield and crop growth. This impact is clearly present in situations with relatively shallow groundwater levels (85 % of the Netherlands, where capillary rise is a well-known source of upward flow; but also in free-draining situations the impact of upward flow is considerable. In the latter case recirculated percolation water is the flow source. To make this impact explicit we implemented a synthetic modelling option that stops upward flow from reaching the root zone, without inhibiting percolation. Such a hypothetically moisture-stressed situation compared to a natural one in the presence of shallow groundwater shows mean yield reductions for grassland, maize and potatoes of respectively 26, 3 and 14 % or respectively about 3.7, 0.3 and 1.5 t dry matter per hectare. About half of the withheld water behind these yield effects comes from recirculated percolation water as occurs in free-drainage conditions and the other half comes from increased upward capillary rise. Soil water and crop growth modelling should consider both capillary rise from groundwater and recirculation of percolation water as this improves the accuracy of yield simulations. This also improves the

  16. Impact of capillary rise and recirculation on simulated crop yields

    Science.gov (United States)

    Kroes, Joop; Supit, Iwan; van Dam, Jos; van Walsum, Paul; Mulder, Martin

    2018-05-01

    Upward soil water flow is a vital supply of water to crops. The purpose of this study is to determine if upward flow and recirculated percolation water can be quantified separately, and to determine the contribution of capillary rise and recirculated water to crop yield and groundwater recharge. Therefore, we performed impact analyses of various soil water flow regimes on grass, maize and potato yields in the Dutch delta. Flow regimes are characterized by soil composition and groundwater depth and derived from a national soil database. The intermittent occurrence of upward flow and its influence on crop growth are simulated with the combined SWAP-WOFOST model using various boundary conditions. Case studies and model experiments are used to illustrate the impact of upward flow on yield and crop growth. This impact is clearly present in situations with relatively shallow groundwater levels (85 % of the Netherlands), where capillary rise is a well-known source of upward flow; but also in free-draining situations the impact of upward flow is considerable. In the latter case recirculated percolation water is the flow source. To make this impact explicit we implemented a synthetic modelling option that stops upward flow from reaching the root zone, without inhibiting percolation. Such a hypothetically moisture-stressed situation compared to a natural one in the presence of shallow groundwater shows mean yield reductions for grassland, maize and potatoes of respectively 26, 3 and 14 % or respectively about 3.7, 0.3 and 1.5 t dry matter per hectare. About half of the withheld water behind these yield effects comes from recirculated percolation water as occurs in free-drainage conditions and the other half comes from increased upward capillary rise. Soil water and crop growth modelling should consider both capillary rise from groundwater and recirculation of percolation water as this improves the accuracy of yield simulations. This also improves the accuracy of the

  17. 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.

  18. INFLUENCE OF SLUDGE RECIRCULATION ON NUTRIENT REMOVAL IN SUBMERGED MEMBRANE BIOREACTORS

    Directory of Open Access Journals (Sweden)

    María Casamitjanaa Causa

    2015-06-01

    Full Text Available Membrane bioreactors (MBR technology is a well-developed wastewater treatment process; however, the integrated operation between biological reactions and physical filtration has been poorly studied. Among other operational parameters, optimal control of sludge recirculation can enhance nitrogen and phosphorous removal processes, but the effects on sludge filterability is not clear. In this paper, different recirculation flow rates were tested to evaluate consequences on sludge filterability and nutrient removal in a MBR-UCT pilot plant treating real municipal wastewater. Three distinct sludge recirculation flows were studied during 10 weeks [external recirculation (from the membrane tank to the anoxic reactor, anoxic recirculation (from the aerobic to the anoxic reactor and anaerobic recirculation (from the anoxic to the anaerobic reactor]. The obtained results have shown that anaerobic recirculation affected nutrient removal in an inversely proportional way, whereas anoxic recirculation had a directly proportional effect. Referring sludge characteristics, filterability and capillarity suction time (CST remained independent of sludge recirculation, whereas CST is proportional to transmembrane pressure (TMP, which seems to depend on external and anoxic sludge recirculation.

  19. Investigation on inlet recirculation characteristics of double suction centrifugal compressor with unsymmetrical inlet

    Science.gov (United States)

    Yang, Ce; Wang, Yingjun; Lao, Dazhong; Tong, Ding; Wei, Longyu; Liu, Yixiong

    2016-08-01

    The inlet recirculation characteristics of double suction centrifugal compressor with unsymmetrical inlet structures were studied in numerical method, mainly focused on three issues including the amounts and differences of the inlet recirculation in different working conditions, the circumferential non-uniform distributions of the inlet recirculation, the recirculation velocity distributions of the upstream slot of the rear impeller. The results show that there are some differences between the recirculation of the front impeller and that of the rear impeller in whole working conditions. In design speed, the recirculation flow rate of the rear impeller is larger than that of the front impeller in the large flow range, but in the small flow range, the recirculation flow rate of the rear impeller is smaller than that of the front impeller. In different working conditions, the recirculation velocity distributions of the front and rear impeller are non-uniform along the circumferential direction and their non-uniform extents are quite different. The circumferential non-uniform extent of the recirculation velocity varies with the working conditions change. The circumferential non-uniform extent of the recirculation velocity of front impeller and its distribution are determined by the static pressure distribution of the front impeller, but that of the rear impeller is decided by the coupling effects of the inlet flow distortion of the rear impeller, the circumferential unsymmetrical distribution of the upstream slot and the asymmetric structure of the volute. In the design flow and small flow conditions, the recirculation velocities at different circumferential positions of the mean line of the upstream slot cross-section of the rear impeller are quite different, and the recirculation velocities distribution forms at both sides of the mean line are different. The recirculation velocity distributions in the cross-section of the upstream slot depend on the static pressure

  20. 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.

  1. 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.

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

    DEFF Research Database (Denmark)

    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 ...... interact with potassium stronger than active metal species. Among potential carriers, sulfated zirconia is of high interest because its acidic and textural properties can be modified by varying preparation conditions....

  3. ROS-induced ROS release orchestrated by Nox4, Nox2, and mitochondria in VEGF signaling and angiogenesis.

    Science.gov (United States)

    Kim, Young-Mee; Kim, Seok-Jo; Tatsunami, Ryosuke; Yamamura, Hisao; Fukai, Tohru; Ushio-Fukai, Masuko

    2017-06-01

    Reactive oxygen species (ROS) derived from NADPH oxidase (NOX) and mitochondria play a critical role in growth factor-induced switch from a quiescent to an angiogenic phenotype in endothelial cells (ECs). However, how highly diffusible ROS produced from different sources can coordinate to stimulate VEGF signaling and drive the angiogenic process remains unknown. Using the cytosol- and mitochondria-targeted redox-sensitive RoGFP biosensors with real-time imaging, here we show that VEGF stimulation in human ECs rapidly increases cytosolic RoGFP oxidation within 1 min, followed by mitochondrial RoGFP oxidation within 5 min, which continues at least for 60 min. Silencing of Nox4 or Nox2 or overexpression of mitochondria-targeted catalase significantly inhibits VEGF-induced tyrosine phosphorylation of VEGF receptor type 2 (VEGFR2-pY), EC migration and proliferation at the similar extent. Exogenous hydrogen peroxide (H 2 O 2 ) or overexpression of Nox4, which produces H 2 O 2 , increases mitochondrial ROS (mtROS), which is prevented by Nox2 siRNA, suggesting that Nox2 senses Nox4-derived H 2 O 2 to promote mtROS production. Mechanistically, H 2 O 2 increases S36 phosphorylation of p66Shc, a key mtROS regulator, which is inhibited by siNox2, but not by siNox4. Moreover, Nox2 or Nox4 knockdown or overexpression of S36 phosphorylation-defective mutant p66Shc(S36A) inhibits VEGF-induced mtROS, VEGFR2-pY, EC migration, and proliferation. In summary, Nox4-derived H 2 O 2 in part activates Nox2 to increase mtROS via pSer36-p66Shc, thereby enhancing VEGFR2 signaling and angiogenesis in ECs. This may represent a novel feed-forward mechanism of ROS-induced ROS release orchestrated by the Nox4/Nox2/pSer36-p66Shc/mtROS axis, which drives sustained activation of angiogenesis signaling program. Copyright © 2017 the American Physiological Society.

  4. Suppression of new particle formation from monoterpene oxidation by NOx

    Science.gov (United States)

    Wildt, J.; Mentel, T. F.; Kiendler-Scharr, A.; Hoffmann, T.; Andres, S.; Ehn, M.; Kleist, E.; Müsgen, P.; Rohrer, F.; Rudich, Y.; Springer, M.; Tillmann, R.; Wahner, A.

    2014-03-01

    The impact of nitrogen oxides (NOx = NO + NO2) on new particle formation (NPF) and on photochemical ozone production from real plant volatile organic compound (BVOC) emissions was studied in a laboratory setup. At high NOx conditions ([BVOC] / [NOx] 23 ppb) new particle formation was suppressed. Instead, photochemical ozone formation was observed resulting in higher hydroxyl radical (OH) and lower nitrogen monoxide (NO) concentrations. When [NO] was reduced back to levels below 1 ppb by OH reactions, NPF was observed. Adding high amounts of NOx caused NPF to be slowed by orders of magnitude compared to analogous experiments at low NOx conditions ([NOx] ~300 ppt), although OH concentrations were higher. Varying NO2 photolysis enabled showing that NO was responsible for suppression of NPF. This suggests that peroxy radicals are involved in NPF. The rates of NPF and photochemical ozone production were related by power law dependence with an exponent approaching -2. This exponent indicated that the overall peroxy radical concentration must have been similar when NPF occurred. Thus, permutation reactions of first-generation peroxy radicals cannot be the rate limiting step in NPF from monoterpene oxidation. It was concluded that permutation reactions of higher generation peroxy-radical-like intermediates limit the rate of new particle formation. In contrast to the strong effects on the particle numbers, the formation of particle mass was substantially less sensitive to NOx concentrations. If at all, yields were reduced by about an order of magnitude only at very high NOx concentrations.

  5. 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...

  6. 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.

  7. 40 CFR 96.142 - CAIR NOX allowance allocations.

    Science.gov (United States)

    2010-07-01

    ... the 3 highest amounts of the unit's adjusted control period heat input for 2000 through 2004, with the adjusted control period heat input for each year calculated as follows: (A) If the unit is coal-fired... CAIR NOX Allowance Allocations § 96.142 CAIR NOX allowance allocations. (a)(1) The baseline heat input...

  8. 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

  9. Ships going slow in reducing their NOx emissions

    NARCIS (Netherlands)

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

    2015-01-01

    Weaddress the lack of temporal information on ship emissions, and report on rapid short-term variations of satellite-derived shipNOx emissions between 2005 and 2012 over European seas. Our inversion is based onOMI observed troposphericNO2 columns and GEOS-Chem simulations. Average European shipNOx

  10. 40 CFR 76.12 - Phase I NOX compliance extension.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 16 2010-07-01 2010-07-01 false Phase I NOX compliance extension. 76.12 Section 76.12 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) ACID RAIN NITROGEN OXIDES EMISSION REDUCTION PROGRAM § 76.12 Phase I NOX compliance extension. (a...

  11. 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

  12. The Effect of Exhaust Gas Recirculation (EGR on the Emission of a Single Cylinder Spark Ignition Engine

    Directory of Open Access Journals (Sweden)

    Limyaa Mahdi Asaad

    2016-07-01

    Full Text Available A single cylinder variable compression ratio spark ignition engine type PRODIT was used in this study. The  experiments  were  conducted  with  gasoline  fuel  (80  octane  No.at  equivalence  ratio  (Ø  =1.  This study examined the effects of exhaust gas recirculation on emission. It was conducted at engine speeds (1500, 1900, 2300 and 2700 r.p.m..The  exhaust  gases  were  added  in  volumetric  ratios  of  10%,  20%  and  30%  of  the  entering  air/fuel charge. The results showed that the EGR addition decreases the CO2 concentrations, in the same time CO and HC concentrations increase remarkably.  NOx concentration decreased highly with the increase of EGR percentage at variable engine speeds and constant torque. Also, it decreased when the engine run  at  constant  speed  and  variable  engine  torque.  The  exhaust  gas  temperature  decreased  with increasing EGR ratio.

  13. Fast spatially resolved exhaust gas recirculation (EGR) distribution measurements in an internal combustion engine using absorption spectroscopy.

    Science.gov (United States)

    Yoo, Jihyung; Prikhodko, Vitaly; Parks, James E; Perfetto, Anthony; Geckler, Sam; Partridge, William P

    2015-09-01

    Exhaust gas recirculation (EGR) in internal combustion engines is an effective method of reducing NOx emissions while improving efficiency. However, insufficient mixing between fresh air and exhaust gas can lead to cycle-to-cycle and cylinder-to-cylinder non-uniform charge gas mixtures of a multi-cylinder engine, which can in turn reduce engine performance and efficiency. A sensor packaged into a compact probe was designed, built and applied to measure spatiotemporal EGR distributions in the intake manifold of an operating engine. The probe promotes the development of more efficient and higher-performance engines by resolving high-speed in situ CO2 concentration at various locations in the intake manifold. The study employed mid-infrared light sources tuned to an absorption band of CO2 near 4.3 μm, an industry standard species for determining EGR fraction. The calibrated probe was used to map spatial EGR distributions in an intake manifold with high accuracy and monitor cycle-resolved cylinder-specific EGR fluctuations at a rate of up to 1 kHz.

  14. A Study on Effect of Recirculated Exhaust Gas upon Performance and Exhaust Emissions in a Power Plant Boiler with FGR System

    Energy Technology Data Exchange (ETDEWEB)

    Bae, Myung-whan; Jung, Kwong-ho; Park, Sung-bum [Gyeongsang Nat’l Univ., Jinju (Korea, Republic of)

    2016-04-15

    The effect of recirculated exhaust gas on performance and exhaust emissions with FGR rate are investigated by using a natural circulation, pressurized draft and water tube boiler with FGR system operating at several boiler loads and over fire air damper openings. The purpose of this study is to apply the FGR system to a power plant boiler for reducing NOx emissions. To activate the combustion, the OFA with 0 to 20% is supplied into the flame. When the suction damper of two stage combustion system installed in the upper side of wind box is opened by handling the lever between 0° and 90°, also, the combustion air supplied to burner is changed. It is found that the fuel consumption rate per evaporation rate did not show an obvious tendency to increase or decrease with rising the FGR rate, and NOx emissions at the same OFA damper opening are decreased, as FGR rates are elevated and boiler loads are dropped. While a trace amount of soot is emitted without regard to the operation conditions of boiler load, OFA damper opening and FGR rate, because soot emissions are eliminated by the electrostatic precipitator with a collecting efficiency of 86.7%.

  15. A Study on Effect of Recirculated Exhaust Gas upon Performance and Exhaust Emissions in a Power Plant Boiler with FGR System

    International Nuclear Information System (INIS)

    Bae, Myung-whan; Jung, Kwong-ho; Park, Sung-bum

    2016-01-01

    The effect of recirculated exhaust gas on performance and exhaust emissions with FGR rate are investigated by using a natural circulation, pressurized draft and water tube boiler with FGR system operating at several boiler loads and over fire air damper openings. The purpose of this study is to apply the FGR system to a power plant boiler for reducing NOx emissions. To activate the combustion, the OFA with 0 to 20% is supplied into the flame. When the suction damper of two stage combustion system installed in the upper side of wind box is opened by handling the lever between 0° and 90°, also, the combustion air supplied to burner is changed. It is found that the fuel consumption rate per evaporation rate did not show an obvious tendency to increase or decrease with rising the FGR rate, and NOx emissions at the same OFA damper opening are decreased, as FGR rates are elevated and boiler loads are dropped. While a trace amount of soot is emitted without regard to the operation conditions of boiler load, OFA damper opening and FGR rate, because soot emissions are eliminated by the electrostatic precipitator with a collecting efficiency of 86.7%.

  16. Discussion of the effects of recirculating exhaust air on performance and efficiency of a typical microturbine

    International Nuclear Information System (INIS)

    De Paepe, Ward; Delattin, Frank; Bram, Svend; De Ruyck, Jacques

    2012-01-01

    This paper reports on a specific phenomenon, noticed during steam injection experiments on a microturbine. During the considered experiments, measurements indicated an unsteady inlet air temperature of the compressor, resulting in unstable operation of the microturbine. Non-continuous exhaust air recirculation was a possible explanation for the observed behaviour of the microturbine. The aim of this paper is to investigate and demonstrate the effects of exhaust recirculation on a microgasturbine. Depending on wind direction, exhaust air re-entered the engine, resulting in changing inlet conditions which affects the operating regime of the microturbine. For this paper, a series of experiments were performed in the wind tunnel. These series of experiments allowed investigation of the effect of the wind direction on flue gasses flow. Next to the experiments, steady-state simulations of exhaust recirculation were performed in order to study the effect of exhaust recirculation on thermodynamic performance of the microturbine. Dynamic simulations of the non-continuous recirculation revealed the effects of frequency and amplitude on average performance and stability. Results from simulations supported the important impact of exhaust recirculation. Wind tunnel tests demonstrated the influence of the wind direction on recirculation and revealed the necessity to heighten the stack, thus preventing exhaust recirculation. -- Highlights: ► Unstable operation of a T100 microturbine during steam injection tests was noticed, caused by exhaust gas recirculation. ► Wind tunnel tests were performed to study the effect of the wind direction on the recirculation process. ► Steady-state simulations to investigate the effect of exhaust gas recirculation on thermodynamic performance. ► Dynamic simulations to reveal effects of frequency and amplitude on average performance and stability. ► Wind tunnel tests revealed the necessity to heighten the stack to prevent exhaust

  17. NADPH Oxidase, NOX1, Mediates Vascular Injury in Ischemic Retinopathy

    Science.gov (United States)

    Deliyanti, Devy; Rana, Indrajeetsinh; Miller, Antonia G.; Agrotis, Alex; Armani, Roksana; Szyndralewiez, Cédric; Wingler, Kirstin; Touyz, Rhian M.; Cooper, Mark E.; Jandeleit-Dahm, Karin A.; Schmidt, Harald H.H.W.

    2014-01-01

    Abstract Aims: Ischemic retinal diseases such as retinopathy of prematurity are major causes of blindness due to damage to the retinal microvasculature. Despite this clinical situation, retinopathy of prematurity is mechanistically poorly understood. Therefore, effective preventative therapies are not available. However, hypoxic-induced increases in reactive oxygen species (ROS) have been suggested to be involved with NADPH oxidases (NOX), the only known dedicated enzymatic source of ROS. Our major aim was to determine the contribution of NOX isoforms (1, 2, and 4) to a rodent model of retinopathy of prematurity. Results: Using a genetic approach, we determined that only mice with a deletion of NOX1, but not NOX2 or NOX4, were protected from retinal neovascularization and vaso-obliteration, adhesion of leukocytes, microglial accumulation, and the increased generation of proangiogenic and proinflammatory factors and ROS. We complemented these studies by showing that the specific NOX inhibitor, GKT137831, reduced vasculopathy and ROS levels in retina. The source of NOX isoforms was evaluated in retinal vascular cells and neuro-glial elements. Microglia, the immune cells of the retina, expressed NOX1, 2, and 4 and responded to hypoxia with increased ROS formation, which was reduced by GKT137831. Innovation: Our studies are the first to identify the NOX1 isoform as having an important role in the pathogenesis of retinopathy of prematurity. Conclusions: Our findings suggest that strategies targeting NOX1 have the potential to be effective treatments for a range of ischemic retinopathies. Antioxid. Redox Signal. 20, 2726–2740. PMID:24053718

  18. Ozonation control and effects of ozone on water quality in recirculating aquaculture systems

    DEFF Research Database (Denmark)

    Spiliotopoulou, Aikaterini; Rojas-Tirado, Paula Andrea; Chetri, Ravi K.

    2018-01-01

    To address the undesired effect of chemotherapeutants in aquaculture, ozone has been suggested as an alternative to improve water quality. To ensure safe and robust treatment, it is vital to define the ozone demand and ozone kinetics of the specific water matrix to avoid ozone overdose. Different...... ozone dosages were applied to water in freshwater recirculating aquaculture systems (RAS). Experiments were performed to investigate ozone kinetics and demand, and to evaluate the effects on the water quality, particularly in relation to fluorescent organic matter. This study aimed at predicting...... a suitable ozone dosage for water treatment based on daily ozone demand via laboratory studies. These ozone dosages will be eventually applied and maintained at these levels in pilot-scale RAS to verify predictions. Selected water quality parameters were measured, including natural fluorescence and organic...

  19. A power recirculating test rig for ball screw endurance tests

    Directory of Open Access Journals (Sweden)

    Giberti Hermes

    2016-01-01

    Full Text Available A conceptual design of an innovative test rig for endurance tests of ball screws is presented in this paper. The test rig layout is based on the power recirculating principle and it also allows to overtake the main critical issues of the ball screw endurance tests. Among these there are the high power required to make the test, the lengthy duration of the same and the high loads between the screw and the frame that holds it. The article describes the test rig designed scheme, the kinematic expedients to be adopted in order to obtain the required performance and functionality and the sizing procedure to choose the actuation system.

  20. Monitoring of Leachate Recirculation in a Bioreactor Using Electrical Resistivity

    Science.gov (United States)

    Grellier, S.; Bureau, N.; Robain, H.; Tabbagh, A.; Camerlynck, C.; Guerin, R.

    2004-05-01

    The bioreactor is a concept of waste landfill management consisting in speeding up the biodegradation by optimizing the moisture content through leachate recirculation. Electrical resistivity tomography (ERT) is carried out with fast resistivity-meter (Syscal Pro, IRIS Instruments, developed in the framework of the research project CERBERE 01V0665-69, funded by the French Research Ministry) to monitor leachate recirculation. During a recirculation period waste moisture increases, so that electrical resistivity may decrease, but at the same time temperature and mineralization of both waste and leachate become intermixed. If waste temperature is much higher than leachate temperature electrical resistivity will not decrease as much as if the temperature difference was smaller. If leachate mineralization (i.e. leachate conductivity) is higher than that of wet waste in the landfill, electrical resistivity will tend to decrease. Otherwise for example after an addition of rain water into the leachate storage or in case of very wet waste, the resistivities of each medium (leachate and wet waste) can be almost the same, so that leachate mineralization will not have a great influence on waste resistivity. Resistivity measurements were performed during 85 minutes injection trials (with a discharge of 20 m3 h-1) where leachate was injected through a vertical borehole perforated between 1.85 and 4.15 m. Three first measurements are made during the injection (3, 30 and 60 minutes from the beginning of the injection) and the two other after the injection period (8 and 72 minutes after the end of the injection). Apparent and interpreted resistivity variations that occurred during injection trials, expressed as the relative differences (in %) between apparent, respectively interpreted, resistivity during injection and apparent, respectively interpreted, resistivity before injection (reference measurement) show the formation of a plume (a negative anomaly: resistivity decreases with

  1. Laser scanning of a recirculation zone on the Bolund escarpment

    DEFF Research Database (Denmark)

    Mann, Jakob; Angelou, Nikolas; Sjöholm, Mikael

    2012-01-01

    Rapid variations in the height of the recirculation zone are measured with a scanning wind lidar over a small escarpment on the Bolund Peninsula. The lidar is essentially a continuous-wave laser Doppler anemometer with the capability of rapidly changing the focus distance and the beam direction....... The instrument measures the line-ofsight velocity 390 times per second and scans ten wind profiles from the ground up to seven meters per second. The results will be used to test computational fluid dynamics models for flow over terrain, and has relevance for wind energy. The development of multiple lidar...

  2. Laser scanning of a recirculation zone on the Bolund escarpment

    DEFF Research Database (Denmark)

    Mann, Jakob; Angelou, Nikolas; Sjöholm, Mikael

    2014-01-01

    Rapid variations in the height of the recirculation zone are measured with a scanning wind lidar over a small escarpment on the Bolund Peninsula. The lidar is essentially a continuous-wave laser Doppler anemometer with the capability of rapidly changing the focus distance and the beam direction....... The instrument measures the line-of-sight velocity 390 times per second and scans ten wind profiles from the ground up to seven meters per second. We observe a sharp interface between slow and fast moving fluid after the escarpment, and the interface is moving rapidly up and down. This implies that the position...

  3. Microscreen effects on water quality in replicated recirculating aquaculture systems

    DEFF Research Database (Denmark)

    Fernandes, Paulo; Pedersen, Lars-Flemming; Pedersen, Per Bovbjerg

    2015-01-01

    This study investigated the effects of three microscreen mesh sizes (100, 60 and 20 μm) on water quality and rainbow trout (Oncorhynchus mykiss) performance compared to a control group without microscreens, in triplicated recirculating aquaculture systems (RAS). Operational conditions were kept....... Fish performed similarly in all treatments. Preliminary screening of trout gills did not reveal any pathological changes related to microscreen filtration and the resulting water quality. Biofilter performance was also unaffected, with 0′-order nitrification rates (k0a) being equivalent for all twelve...

  4. Gun and optics calculations for the Fermilab recirculation experiment

    International Nuclear Information System (INIS)

    Kroc, T.

    1997-10-01

    Fermilab is investigating electron cooling to recycle 8 Gev antiprotons recovered from the Tevatron. To do so, it is developing an experiment to recirculate 2 Mev electrons generated by a Pelletron at National Electrostatics Corporation. This paper reports on the optics calculations done in support of that work. We have used the computer codes EGN2 and MacTrace to represent the gun area and acceleration columns respectively. In addition to the results of our simulations, we discuss some of the problems encountered in interfacing the two codes

  5. Adaptive feedforward control of exhaust recirculation in large diesel engines

    DEFF Research Database (Denmark)

    Nielsen, Kræn Vodder; Blanke, Mogens; Eriksson, Lars

    2017-01-01

    is generalized to a class of first order Hammerstein systems with sensor delay and exponentially converging bounds of the control error are proven analytically. It is then shown how to apply the method to the EGR system of a two-stroke crosshead diesel engine. The controller is validated by closed loop......Environmental concern has led the International Maritime Organization to restrict NO푥 emissions from marine diesel engines. Exhaust gas recirculation (EGR) systems have been introduced in order to comply to the new standards. Traditional fixed-gain feedback methods are not able to control the EGR...

  6. Lower operating cost due to compressed-air recirculation

    Energy Technology Data Exchange (ETDEWEB)

    Schauwecker, F

    1979-01-01

    Compressed air containing dirt and aggressive substances may cause damage in pipelines and pneumatic tools, equipment and systems. In consequence, operating costs can be greatly reduced by cleaning and recirculation of compressed air. Compressed-air driers are among the most common systems used for this purpose. Most of these driers are refrigeration driers; adsorption driers are less common. Refrigeration driers consist of a heat exchanger system, a separation system, and a power-controlled refrigerator. The water vapour concentration is proportional to the air temperature; for this reason, the pressure dew point should be as low as possible, i.e. about 1.5/sup 0/C.

  7. A recirculating hydroponic system for studying peanut (Arachis hypogaea L.)

    Science.gov (United States)

    Mackowiak, C. L.; Wheeler, R. M.; Stutte, G. W.; Yorio, N. C.; Ruffe, L. M.; Sager, J. C. (Principal Investigator)

    1998-01-01

    Peanut (Arachis hypogaea L.) plants were grown hydroponically, using continuously recirculating nutrient solution. Two culture tray designs were tested; one tray design used only nutrient solution, while the other used a sphagnum-filled pod development compartment just beneath the cover and above the nutrient solution. Both trays were fitted with slotted covers to allow developing gynophores to reach the root zone. Peanut seed yields averaged 350 gm-2 dry mass, regardless of tray design, suggesting that substrate is not required for hydroponic peanut production.

  8. Increases to Biogenic Secondary Organic Aerosols from SO2 and NOx in the Southeastern US

    Science.gov (United States)

    Russell, L. M.; Liu, J.; Ruggeri, G.; Takahama, S.; Claflin, M. S.; Ziemann, P. J.; Lee, A.; Murphy, B.; Pye, H. O. T.; Ng, N. L.; McKinney, K. A.; Surratt, J. D.

    2017-12-01

    During the 2013 Southern Oxidant and Aerosol Study, Fourier Transform Infrared Spectroscopy (FTIR) and Aerosol Mass Spectrometer (AMS) measurements of submicron mass were collected at Look Rock, Tennessee, and Centreville, Alabama. The low NOx, low wind, little rain, and increased daytime isoprene emissions led to multi-day stagnation events at Look Rock that provided clear evidence of particle-phase sulfate enhancing biogenic secondary organic aerosol (bSOA) by selective uptake. Organic mass (OM) sources were apportioned as 42% "vehicle-related" and 54% bSOA, with the latter including "sulfate-related bSOA" that correlated to sulfate (r=0.72) and "nitrate-related bSOA" that correlated to nitrate (r=0.65). Single-particle mass spectra showed three composition types that corresponded to the mass-based factors with spectra cosine similarity of 0.93 and time series correlations of r>0.4. The vehicle-related OM with m/z 44 was correlated to black carbon, "sulfate-related bSOA" was on particles with high sulfate, and "nitrate-related bSOA" was on all particles. The similarity of the m/z spectra (cosine similarity=0.97) and the time series correlation (r=0.80) of the "sulfate-related bSOA" to the sulfate-containing single-particle type provide evidence for particle composition contributing to selective uptake of isoprene oxidation products onto particles that contain sulfate from power plants. Since Look Rock had much less NOx than Centreville, comparing the bSOA at the two sites provides an evaluation of the role of NOx for bSOA. CO and submicron sulfate and OM concentrations were 15-60 % higher at Centreville than at Look Rock but their time series had moderate correlations of r= 0.51, 0.54, and 0.47, respectively. However, NOx had no correlation (r=0.08) between the two sites. OM correlated with the higher NOx levels at Centreville but with O3 at Look Rock. OM sources identified by Positive Matrix Factorization had three very similar factors at both sites from FTIR

  9. Power plant including an exhaust gas recirculation system for injecting recirculated exhaust gases in the fuel and compressed air of a gas turbine engine

    Science.gov (United States)

    Anand, Ashok Kumar; Nagarjuna Reddy, Thirumala Reddy; Shaffer, Jason Brian; York, William David

    2014-05-13

    A power plant is provided and includes a gas turbine engine having a combustor in which compressed gas and fuel are mixed and combusted, first and second supply lines respectively coupled to the combustor and respectively configured to supply the compressed gas and the fuel to the combustor and an exhaust gas recirculation (EGR) system to re-circulate exhaust gas produced by the gas turbine engine toward the combustor. The EGR system is coupled to the first and second supply lines and configured to combine first and second portions of the re-circulated exhaust gas with the compressed gas and the fuel at the first and second supply lines, respectively.

  10. 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.

  11. Control methodologies based on geothermal recirculating aquaculture system

    International Nuclear Information System (INIS)

    Farghally, Hanaa M.; Atia, Doaa M.; El-madany, Hanaa T.; Fahmy, Faten H.

    2014-01-01

    One of the most common uses of geothermal heat is in RAS (recirculation aquaculture systems) where the water temperature is accurately controlled for optimum growing conditions for sustainable and intensive rearing of marine and freshwater fish. This paper presents a design for RAS rearing tank and plate type heat exchanger to be used with geothermal energy as a source of heating water. A well at Umm Huweitat on the Red Sea is used as a source of geothermal energy. The heat losses from the RAS tank are calculated using Geo Heat Center Software. Then a plate type heat exchanger is designed using the epsilon–NTU (number of transfer units) analysis method. For optimal growth and abundance of production, a different techniques of control system are applied to control the water temperature. The total system is built in MATLAB/SIMULINK to study the overall performance of control unit. Finally, a comparison between PI, Fuzzy-PID, and Fuzzy Logic Control has been done. - Highlights: • Design recirculating aquaculture system using geothermal energy. • Design a PI controller for water temperature control. • Design a Fuzzy logic controller for water temperature control. • Design a Fuzzy-PID controller for water temperature control. • Comparison between different control systems

  12. Turbulent characteristics of shear-thinning fluids in recirculating flows

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, A.S. [Inst. Superior de Engenharia do Porto (Portugal). Dept. de Engenharia Quimica; Pinho, F.T. [Centro de Estudos de Fenomenos de Transporte, Departamento de Engenharia Mecanica e Gestao Industrial, Faculdade de Engenharia da Universidade do Porto, Rua dos Bragas, 4050-123 Porto (Portugal)

    2000-03-01

    A miniaturised fibre optic laser-Doppler anemometer was used to carry out a detailed hydrodynamic investigation of the flow downstream of a sudden expansion with 0.1-0.2% by weight shear-thinning aqueous solutions of xanthan gum. Upstream of the sudden expansion the pipe flow was fully-developed and the xanthan gum solutions exhibited drag reduction with corresponding lower radial and tangential normal Reynolds stresses, but higher axial Reynolds stress near the wall and a flatter axial mean velocity profile in comparison with Newtonian flow. The recirculation bubble length was reduced by more than 20% relative to the high Reynolds number Newtonian flow, and this was attributed to the occurrence further upstream of high turbulence for the non-Newtonian solutions, because of advection of turbulence and earlier high turbulence production in the shear layer. Comparisons with the measurements of Escudier and Smith (1999) with similar fluids emphasized the dominating role of inlet turbulence. The present was less anisotropic, and had lower maximum axial Reynolds stresses (by 16%) but higher radial turbulence (20%) than theirs. They reported considerably longer recirculating bubble lengths than we do for similar non-Newtonian fluids and Reynolds numbers. (orig.)

  13. Linear fixed-field multipass arcs for recirculating linear accelerators

    Directory of Open Access Journals (Sweden)

    V. S. Morozov

    2012-06-01

    Full Text Available Recirculating linear accelerators (RLA’s provide a compact and efficient way of accelerating particle beams to medium and high energies by reusing the same linac for multiple passes. In the conventional scheme, after each pass, the different energy beams coming out of the linac are separated and directed into appropriate arcs for recirculation, with each pass requiring a separate fixed-energy arc. In this paper we present a concept of an RLA return arc based on linear combined-function magnets, in which two and potentially more consecutive passes with very different energies are transported through the same string of magnets. By adjusting the dipole and quadrupole components of the constituting linear combined-function magnets, the arc is designed to be achromatic and to have zero initial and final reference orbit offsets for all transported beam energies. We demonstrate the concept by developing a design for a droplet-shaped return arc for a dogbone RLA capable of transporting two beam passes with momenta different by a factor of 2. We present the results of tracking simulations of the two passes and lay out the path to end-to-end design and simulation of a complete dogbone RLA.

  14. CONVECTIVE HEAT TRANSFER IN CYCLONE DEVICE WITH EXTERNAL GAS RECIRCULATION

    Directory of Open Access Journals (Sweden)

    S. V. Karpov

    2016-01-01

    Full Text Available The article considers the convective heat transfer on the surface of a hollow cylinder or several billets in a cyclone device with the new principle of external gas recirculation. According to this principle, transport of coolant from the lateral surface of the chamber, where the temperature is the highest, in the axial region is being fulfilled due to the pressure drop between the wall and axial areas of cyclonic flow. Dependency analysis of average and local heat transfer coefficients from operational and geometrical parameters has been performed; the generalized similarity equations for the calculation of the latter have been suggested. It is demonstrated that in case of download of a cyclone chamber with several billets, the use of the considered scheme of the external recirculation due to the specific characteristics of aerodynamics practically does not lead to noticeable changes in the intensity of convective heat transfer. Both experimental data and the numerical simulation results obtained with the use of OpenFOAM platform were used in the work. The investigations fulfilled will expand the area of the use of cyclone heating devices.

  15. Design validation and performance of closed loop gas recirculation system

    International Nuclear Information System (INIS)

    Kalmani, S.D.; Majumder, G.; Mondal, N.K.; Shinde, R.R.; Joshi, A.V.

    2016-01-01

    A pilot experimental set up of the India Based Neutrino Observatory's ICAL detector has been operational for the last 4 years at TIFR, Mumbai. Twelve glass RPC detectors of size 2 × 2 m 2 , with a gas gap of 2 mm are under test in a closed loop gas recirculation system. These RPCs are continuously purged individually, with a gas mixture of R134a (C 2 H 2 F 4 ), isobutane (iC 4 H 10 ) and sulphur hexafluoride (SF 6 ) at a steady rate of 360 ml/h to maintain about one volume change a day. To economize gas mixture consumption and to reduce the effluents from being released into the atmosphere, a closed loop system has been designed, fabricated and installed at TIFR. The pressure and flow rate in the loop is controlled by mass flow controllers and pressure transmitters. The performance and integrity of RPCs in the pilot experimental set up is being monitored to assess the effect of periodic fluctuation and transients in atmospheric pressure and temperature, room pressure variation, flow pulsations, uniformity of gas distribution and power failures. The capability of closed loop gas recirculation system to respond to these changes is also studied. The conclusions from the above experiment are presented. The validations of the first design considerations and subsequent modifications have provided improved guidelines for the future design of the engineering module gas system.

  16. Continuous hydroponic wheat production using a recirculating system

    Science.gov (United States)

    Mackowiak, C. L.; Owens, L. P.; Hinkle, C. R.; Prince, R. P.

    1989-01-01

    Continuous crop production, where plants of various ages are growing simultaneously in a single recirculating nutrient solution, is a possible alternative to batch production in a Controlled Ecological Life Support System. A study was conducted at John F. Kennedy Space Center where 8 trays (0.24 sq m per tray) of Triticum aestivum L. Yecora Rojo were grown simultaneously in a growth chamber at 23 C, 65 percent relative humidity, 1000 ppm CO2, continuous light, with a continuous flow, thin film nutrient delivery system. The same modified Hoagland nutrient solution was recirculated through the plant trays from an 80 L reservoir throughout the study. It was maintained by periodic addition of water and nutrients based on chemical analyses of the solution. The study was conducted for 216 days, during which 24 trays of wheat were consecutively planted (one every 9 days), 16 of which were grown to maturity and harvested. The remaining 8 trays were harvested on day 216. Grain yields averaged 520 g m(exp -2), and had an average edible biomass of 32 percent. Consecutive yields were unaffected by nutrient solution age. It was concluded that continual wheat production will work in this system over an extended period of time. Certain micronutrient deficiencies and toxicities posed problems and must be addressed in future continuous production systems.

  17. Experimental and theoretical analysis of effects of atomic, diatomic and polyatomic inert gases in air and EGR on mixture properties, combustion, thermal efficiency and NOx emissions of a pilot-ignited NG engine

    International Nuclear Information System (INIS)

    Li, Weifeng; Liu, Zhongchang; Wang, Zhongshu; Dou, Huili

    2015-01-01

    Highlights: • The specific heat ratio of the mixture increases with increasing Ar. • The thermal efficiency increases first and then decreases with increasing Ar. • Mechanisms of reducing NOx emissions are different for different dilution gases. • A suitable inert gas should be used to meet different requirements. - Abstract: Argon (Ar), nitrogen (N_2) and carbon dioxide (CO_2), present in exhaust gas recirculation (EGR) and air, are common atomic, diatomic and polyatomic inert gases, separately. As dilution gases, they are always added into the intake charge to reduce nitrogen oxides (NOx) emissions, directly or along with EGR and air. This paper presents the effects of Ar, N_2 and CO_2 on mixture properties, combustion, thermal efficiency and NOx emissions of pilot-ignited natural gas engines. Thermodynamic properties of the air-dilution gas mixture with increasing dilution gases, including density, gas constant, specific heat ratio, specific heat capacity, heat capacity and thermal diffusivity, were analyzed theoretically using thermodynamic relations and ideal gas equations based on experimental results. The thermal and diluent effects of dilution gases on NOx emissions were investigated based on Arrhenius Law and Zeldovich Mechanism, experimentally and theoretically. The experiments were arranged based on an electronically controlled heavy-duty, 6-cylinder, turbocharged, pilot-ignited natural gas engine. The resulted show that adding different inert gases into the intake charge had different influences on the thermodynamic properties of the air-dilution gas mixture. No great change in combustion phase was found with increasing dilution ratio (DR) of Ar, while the flame development duration increased significantly and CA50 moved far away from combustion top dead center (TDC) obviously with increasing DR for both of N_2 and CO_2. Adding Ar was superior in maintaining high thermal efficiencies than CO_2 and N_2, but adding CO_2 was superior in maintaining

  18. Constitutive NADPH-dependent electron transferase activity of the Nox4 dehydrogenase domain.

    Science.gov (United States)

    Nisimoto, Yukio; Jackson, Heather M; Ogawa, Hisamitsu; Kawahara, Tsukasa; Lambeth, J David

    2010-03-23

    NADPH oxidase 4 (Nox4) is constitutively active, while Nox2 requires the cytosolic regulatory subunits p47(phox) and p67(phox) and activated Rac with activation by phorbol 12-myristate 13-acetate (PMA). This study was undertaken to identify the domain on Nox4 that confers constitutive activity. Lysates from Nox4-expressing cells exhibited constitutive NADPH- but not NADH-dependent hydrogen peroxide production with a K(m) for NADPH of 55 +/- 10 microM. The concentration of Nox4 in cell lysates was estimated using Western blotting and allowed calculation of a turnover of approximately 200 mol of H(2)O(2) min(-1) (mol of Nox4)(-1). A chimeric protein (Nox2/4) consisting of the Nox2 transmembrane (TM) domain and the Nox4 dehydrogenase (DH) domain showed H(2)O(2) production in the absence of cytosolic regulatory subunits. In contrast, chimera Nox4/2, consisting of the Nox4 TM and Nox2 DH domains, exhibited PMA-dependent activation that required coexpression of regulatory subunits. Nox DH domains from several Nox isoforms were purified and evaluated for their electron transferase activities. Nox1 DH, Nox2 DH, and Nox5 DH domains exhibited barely detectable activities toward artificial electron acceptors, while the Nox4 DH domain exhibited significant rates of reduction of cytochrome c (160 min(-1), largely superoxide dismutase-independent), ferricyanide (470 min(-1)), and other electron acceptors (artificial dyes and cytochrome b(5)). Rates were similar to those observed for H(2)O(2) production by the Nox4 holoenzyme in cell lysates. The activity required added FAD and was seen with NADPH but not NADH. These results indicate that the Nox4 DH domain exists in an intrinsically activated state and that electron transfer from NADPH to FAD is likely to be rate-limiting in the NADPH-dependent reduction of oxygen by holo-Nox4.

  19. Directional migration of recirculating lymphocytes through lymph nodes via random walks.

    Directory of Open Access Journals (Sweden)

    Niclas Thomas

    Full Text Available Naive T lymphocytes exhibit extensive antigen-independent recirculation between blood and lymph nodes, where they may encounter dendritic cells carrying cognate antigen. We examine how long different T cells may spend in an individual lymph node by examining data from long term cannulation of blood and efferent lymphatics of a single lymph node in the sheep. We determine empirically the distribution of transit times of migrating T cells by applying the Least Absolute Shrinkage & Selection Operator (LASSO or regularised S-LASSO to fit experimental data describing the proportion of labelled infused cells in blood and efferent lymphatics over time. The optimal inferred solution reveals a distribution with high variance and strong skew. The mode transit time is typically between 10 and 20 hours, but a significant number of cells spend more than 70 hours before exiting. We complement the empirical machine learning based approach by modelling lymphocyte passage through the lymph node insilico. On the basis of previous two photon analysis of lymphocyte movement, we optimised distributions which describe the transit times (first passage times of discrete one dimensional and continuous (Brownian three dimensional random walks with drift. The optimal fit is obtained when drift is small, i.e. the ratio of probabilities of migrating forward and backward within the node is close to one. These distributions are qualitatively similar to the inferred empirical distribution, with high variance and strong skew. In contrast, an optimised normal distribution of transit times (symmetrical around mean fitted the data poorly. The results demonstrate that the rapid recirculation of lymphocytes observed at a macro level is compatible with predominantly randomised movement within lymph nodes, and significant probabilities of long transit times. We discuss how this pattern of migration may contribute to facilitating interactions between low frequency T cells and antigen

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

    Science.gov (United States)

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

  1. 40 CFR 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...

  2. 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...

  3. 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...

  4. 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...

  5. 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...

  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. Wood combustion and NOx formation control

    International Nuclear Information System (INIS)

    Tewksbury, C.

    1991-01-01

    The control of wood combustion on stoker fed grates for optimum efficiency and the limiting of NO x (oxides of nitrogen) formation are not necessarily contradictory. This paper presents a matrix of air/fuel ratio control options, then discusses simple on-line monitoring techniques and the importance of operator training and alertness. The significance of uniform fuel feed and air distribution is emphasized. The relationships between combustion control and NO x formation are outlined both in theory and as tested. The experience of the McNeil Generating Station (the largest wood-fired, single boiler, stoker grate, utility electric generating station in the world) is used to demonstrate the theoretical principles. It has been observed that NO x emissions firing 100% whole tree chips with moisture contents as low as 40% by weight can be as low as 0.13 lb/MMBtu (MMBtu = 10 6 Btu) while still achieving a boiler efficiency in the range of 68% to 73% (in the high end of the design range) without the use of post-combustion treatment or flue gas recirculation (FGR). Problems of combustion and emissions control at steaming rates other than normal full-load are also examined. 2 figs., 4 tabs

  10. Experimental Study of Effect of EGR Rates on NOx and Smoke Emission of LHR Diesel Engine Fueled with Blends of Diesel and Neem Biodiesel

    Science.gov (United States)

    Modi, Ashishkumar Jashvantlal; Gosai, Dipak Chimangiri; Solanki, Chandresh Maheshchandra

    2018-04-01

    Energy conservation and efficiency have been the quest of engineers concerned with internal combustion engine. Theoretically, if the heat rejected could be reduced, then the thermal efficiency would be improved, at least up to the limit set by the second law of thermodynamics. For current work a ceramic coated twin cylinder water-cooled diesel engine using blends of diesel and Neem biodiesel as fuel was evaluated for its performance and exhaust emissions. Multi cylinder vertical water cooled self-governed diesel engine, piston, top surface of cylinder head and liners were fully coated with partially stabilized zirconia as ceramic material attaining an adiabatic condition. Previous studies have reported that combustion of Neem biodiesel emitted higher NOx, while hydrocarbon and smoke emissions were lower than conventional diesel fuel. Exhaust gas recirculation (EGR) is one of the techniques being used to reduce NOx emission from diesel engines; because it decreases both flame temperature and oxygen concentration in the combustion chamber. The stationary diesel engine was run in laboratory at a high load condition (85% of maximum load), fixed speed (2000 rpm) and various EGR rates of 5-40% (with 5% increment). Various measurements like fuel flow, exhaust temperature, exhaust emission measurement and exhaust smoke test were carried out. The results indicate improved fuel economy and reduced pollution levels for the low heat rejection (LHR) engine. The results showed that, at 5% EGR with TB10, both NOx and smoke opacity were reduced by 26 and 15%, respectively. Furthermore, TB20 along with 10% EGR was also able to reduce both NOx and smoke emission by 34 and 30%, respectively compared to diesel fuel without EGR.

  11. Low Load Model of a Once-through Boiler with Recirculation

    DEFF Research Database (Denmark)

    Trangbæk, Klaus

    2006-01-01

    A dynamic simulation model of a once-through boiler in low to medium load is developed. When the system is in low load, water from the evaporator is recirculated through a bottle. This recirculation system is included in the model, which is then shown to fit closed-loop data from a real plant...

  12. Coastal recirculation potential affecting air pollutants in Portugal: The role of circulation weather types

    Science.gov (United States)

    Russo, Ana; Gouveia, Célia; Levy, Ilan; Dayan, Uri; Jerez, Sonia; Mendes, Manuel; Trigo, Ricardo

    2016-06-01

    Coastal zones are under increasing development and experience air pollution episodes regularly. These episodes are often related to peaks in local emissions from industry or transportation, but can also be associated with regional transport from neighbour urban areas influenced by land-sea breeze recirculation. This study intends to analyze the relation between circulation weather patterns, air mass recirculation and pollution levels in three coastal airsheds of Portugal (Lisbon, Porto and Sines) based on the application of an objective quantitative measure of potential recirculation. Although ventilation events have a dominant presence throughout the studied 9-yrs period on all the three airsheds, recirculation and stagnation conditions occur frequently. The association between NO2, SO2 and O3 levels and recirculation potential is evident during summer months. Under high average recirculation potential and high variability, NO2 and SO2 levels are higher for the three airsheds, whilst for O3 each airshed responds differently. This indicates a high heterogeneity among the three airsheds in (1) the type of emission - traffic or industry - prevailing for each contaminant, and (2) the response to the various circulation weather patterns and recirculation situations. Irrespectively of that, the proposed methodology, based on iterative K-means clustering, allows to identify which prevailing patterns are associated with high recirculation potential, having the advantage of being applicable to any geographical location.

  13. Daily micro particle distribution of an experimental recirculating aquaculture system – A case study

    DEFF Research Database (Denmark)

    Fernandes, Paulo; Pedersen, Lars-Flemming; Pedersen, Per Bovbjerg

    2014-01-01

    The particle size distribution (PSD) in a recirculating aquaculture system (RAS) was investigated duringa 24-h cycle. PSD was analyzed in water sampled at several locations in a recirculation loop containing a60-m drum filter, a submerged fixed-bed biofilter and a trickling filter.In relation...

  14. Physics design and scaling of recirculating induction accelerators: from benchtop prototypes to drivers

    International Nuclear Information System (INIS)

    Barnard, J.J.; Cable, M.D.; Callahan, D.A.

    1996-01-01

    Recirculating induction accelerators (recirculators) have been investigated as possible drivers for inertial fusion energy production because of their potential cost advantage over linear induction accelerators. Point designs were obtained and many of the critical physics and technology issues that would need to be addressed were detailed. A collaboration involving Lawrence Livermore National Laboratory and Lawrence Berkeley National Laboratory researchers is now developing a small prototype recirculator in order to demonstrate an understanding of nearly all of the critical beam dynamics issues that have been raised. We review the design equations for recirculators and demonstrate how, by keeping crucial dimensionless quantities constant, a small prototype recirculator was designed which will simulate the essential beam physics of a driver. We further show how important physical quantities such as the sensitivity to errors of optical elements (in both field strength and placement), insertion/extraction, vacuum requirements, and emittance growth, scale from small-prototype to driver-size accelerator

  15. Pulsed-focusing recirculating linacs for muon acceleration

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Rolland [Muons, Inc., Batavia, IL (United States)

    2014-12-31

    Since the muon has a short lifetime, fast acceleration is essential for high-energy applications such as muon colliders, Higgs factories, or neutrino factories. The best one can do is to make a linear accelerator with the highest possible accelerating gradient to make the accelerating time as short as possible. However, the cost of such a single linear accelerator is prohibitively large due to expensive power sources, cavities, tunnels, and related infrastructure. As was demonstrated in the Thomas Jefferson Accelerator Facility (Jefferson Lab) Continuous Electron Beam Accelerator Facility (CEBAF), an elegant solution to reduce cost is to use magnetic return arcs to recirculate the beam through the accelerating RF cavities many times, where they gain energy on each pass. In such a Recirculating Linear Accelerator (RLA), the magnetic focusing strength diminishes as the beam energy increases in a conventional linac that has constant strength quadrupoles. After some number of passes the focusing strength is insufficient to keep the beam from going unstable and being lost. In this project, the use of fast pulsed quadrupoles in the linac sections was considered for stronger focusing as a function of time to allow more successive passes of a muon beam in a recirculating linear accelerator. In one simulation, it was shown that the number of passes could be increased from 8 to 12 using pulsed magnet designs that have been developed and tested. This could reduce the cost of linac sections of a muon RLA by 8/12, where more improvement is still possible. The expense of a greater number of passes and corresponding number of return arcs was also addressed in this project by exploring the use of ramped or FFAG-style magnets in the return arcs. A better solution, invented in this project, is to use combined-function dipole-quadrupole magnets to simultaneously transport two beams of different energies through one magnet string to reduce costs of return arcs by almost a factor of

  16. Development of a self-consistent lightning NOx simulation in large-scale 3-D models

    Science.gov (United States)

    Luo, Chao; Wang, Yuhang; Koshak, William J.

    2017-03-01

    We seek to develop a self-consistent representation of lightning NOx (LNOx) simulation in a large-scale 3-D model. Lightning flash rates are parameterized functions of meteorological variables related to convection. We examine a suite of such variables and find that convective available potential energy and cloud top height give the best estimates compared to July 2010 observations from ground-based lightning observation networks. Previous models often use lightning NOx vertical profiles derived from cloud-resolving model simulations. An implicit assumption of such an approach is that the postconvection lightning NOx vertical distribution is the same for all deep convection, regardless of geographic location, time of year, or meteorological environment. Detailed observations of the lightning channel segment altitude distribution derived from the NASA Lightning Nitrogen Oxides Model can be used to obtain the LNOx emission profile. Coupling such a profile with model convective transport leads to a more self-consistent lightning distribution compared to using prescribed postconvection profiles. We find that convective redistribution appears to be a more important factor than preconvection LNOx profile selection, providing another reason for linking the strength of convective transport to LNOx distribution.

  17. The CO/NOx emissions of swirled, strongly pulsed jet diffusion flames

    KAUST Repository

    Liao, Ying-Hao; Hermanson, James C.

    2014-01-01

    recirculation within the swirl-induced recirculation zone. Scaling relations, when taking into account the impact of air dilution over an injection cycle on the flame length, reveal a strong correlation between the CO emissions and the global residence time

  18. 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)

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

    Science.gov (United States)

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

    2014-08-01

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

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

    Science.gov (United States)

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

    2013-11-01

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

  1. Exergetic performance analysis of a recirculating aquaculture system

    International Nuclear Information System (INIS)

    Kucuk, Haydar; Midilli, Adnan; Ozdemir, Atilla; Cakmak, Eyuep; Dincer, Ibrahim

    2010-01-01

    This paper examines exergetic aspects of a Recirculation Aquaculture System (RAS) for Black Sea trout (Salmo trutta labrax) fingerling rearing at the Trabzon Central Fisheries Research Institute, Turkey. In its thermodynamic analysis, each component of the RAS is treated as a steady-state steady flow system and its exergetic efficiencies are studied. In addition, the following parameters are measured and recorded in experiments: the mass flow rates, inlet and outlet temperatures and of the system components, surrounding temperatures, and electrical work utilized by the components in the RAS. Based on these experimental data, inlet and outlet exergy values, exergy losses, and exergetic efficiencies of each component in the system are determined to assess their performance. Moreover, the overall system exergy efficiency is determined. The results show that exergy efficiencies of the system components are highly affected by varying input exergy flows as a function of the surrounding temperature and chiller's operating period.

  2. Requirements for longitudinal HOM damping in superconducting recirculating linacs

    International Nuclear Information System (INIS)

    Bisognano, J.J.; Fripp, M.L.

    1989-01-01

    Transverse beam breakup provides the primary current limitation in the operation of superconducting recirculating linacs and requires the significant damping of transverse-deflecting higher order modes. The need to damp the coexisting longitudinal HOMs in these nominally isochronous machines, however, is not as clear. Isochronicity implies that energy variations induced by excitation of longitudinal modes do not translate directly into position and current modulations. Such modulations, if present, could enhance the initial excitation, effectively closing a potentially unstable feedback loop. Design optimization of cavity structures may suggest that no longitudinal damping be provided. On the other hand, easing of the isochronicity requirement may provide desired flexibility in lattice design. In this note, limits are placed on the requirements for longitudinal HOM damping and on the tolerances for isochronicity which are driven by possible longitudinal multipass phenomena. 2 refs., 1 fig

  3. Ultrasonic downcomer flow measurements for recirculating steam generators

    Energy Technology Data Exchange (ETDEWEB)

    Janzen, Victor, E-mail: Victor.Janzen@cnl.ca [Canadian Nuclear Laboratories, Chalk River, ON, Canada K0 J 1J0 (Canada); Luloff, Brian [Canadian Nuclear Laboratories, Chalk River, ON, Canada K0 J 1J0 (Canada); Sedman, Ken [Nuclear Safety Analysis & Support Department, Bruce Power, Toronto, ON, Canada M5G 1X6 (Canada)

    2015-08-15

    Highlights: • Measuring recirculating flow in nuclear steam generators provides useful information. • Flow measurements shed light on component performance and degradation mechanisms. • Commonly used ultrasonic technology and application methods are described. • Results of measurements at several power reactors are summarized. • Potential improvements in reliability and flexibility of application are suggested. - Abstract: Measurements of downcomer flow in nuclear steam generators can provide unique fitness for service and performance indicators related to overall thermalhydraulic performance, safety related secondary-side setpoints and certain forms of degradation. This paper reviews the benefits of downcomer-flow measurements to nuclear power–plant operators, and describes methods that are commonly used. It summarizes the history and state-of-the-art of the most widely used technology, non-intrusive ultrasonic systems, including field applications at several nuclear power plants. It also describes the technical challenges that remain, and summarizes recent technical developments and future improvements.

  4. Off-gas recirculation system for nuclear reactors

    International Nuclear Information System (INIS)

    Eppler, M.; Lade, H.J.

    1975-01-01

    According to the invention, it is suggested to provide a buffer vessel in the ring main of the off-gas recirculation system for off-gases of a nuclear reactor to which all chambers or vessels which may contain radioactively contaminated gases are connected, within the connection line to outside air. This is to prevent the immediate release of an appreciable amount of gas to the outside air due to pressure variations conditioned by the sequence of operations - e.g. on the filling of the coolant storage. After the improvement, the released gas may be reduced to the amount of gas corresponding to the leakage gas flow entering the ring mains system. (TK) [de

  5. Recycling crop residues for use in recirculating hydroponic crop production

    Science.gov (United States)

    Mackowiak, C. L.; Garland, J. L.; Sager, J. C.

    1996-01-01

    As part of bioregenerative life support feasibility testing by NASA, crop residues are being used to resupply elemental nutrients to recirculating hydroponic crop production systems. Methods for recovering nutrients from crop residues have evolved from water soaking (leaching) to rapid aerobic bioreactor processing. Leaching residues recovered the majority of elements but it also recovered significant amounts of soluble organics. The high organic content of leachates was detrimental to plant growth. Aerobic bioreactor processing reduced the organic content ten-fold, which reduced or eliminated phytotoxic effects. Wheat and potato production studies were successful using effluents from reactors having with 8- to 1-day retention times. Aerobic bioreactor effluents supplied at least half of the crops elemental mass needs in these studies. Descriptions of leachate and effluent mineral content, biomass productivity, microbial activity, and nutrient budgets for potato and wheat are presented.

  6. A review of NOx formation mechanisms in recovery furnaces

    International Nuclear Information System (INIS)

    Nichols, K.M.; Thompson, L.M.; Empie, H.J.

    1993-01-01

    Review of NOx formation studies shows that NO forms in recovery furnaces primarily by two independent mechanisms, thermal and fuel. Thermal NO formation is extremely temperature-sensitive. However, theoretical predictions indicate that recovery furnace temperatures are not high enough to form significant thermal NO. Fuel NO formation is less temperature-sensitive, and is related to fuel nitrogen content. Black liquors are shown to contain 0.05 to 0.24 weight percent fuel nitrogen. Conversion of just 20% of this would yield approximately 25-120 ppm NOx (at 8% 0 2 ) in the flue gas, enough to represent the majority of the total NOx. Data from operating recovery furnaces show NOx emissions ranging from near zero to over 100 ppm at 8% 0 2 . An apparent increase in recovery furnace NOx emissions was observed with increasing solids. This increase is much less than predicted by thermal NO formation theory, indicating that other NO formation/destruction mechanisms, such as fuel NO formation, are important. No data are available to show the relative importance of thermal and fuel NO to total NOx during black liquor combustion

  7. Alternative alkali resistant deNOx catalysts

    DEFF Research Database (Denmark)

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

    2012-01-01

    by onepot sol–gel method. All catalysts were characterized by BET, XRPD and NH3-TPD. Initial SCR activities of 8 out of 9 catalysts showed higher NO conversion at least at one temperature in the temperature range 300–500 ◦C compared to the conventional V2O5-WO3/TiO2 catalyst. After potassium poisoning (100......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......–130 µmol of K/g of catalyst) the relative drop in SCR activity and acidity was lower for all the alternative catalysts compared to the industrial V2O5-WO3/TiO2 catalyst. Furthermore, Cu/MOR and Nano-V2O5/Sul-TiO2 catalysts showed 8–16 times higher SCR activities than the conventional even after high...

  8. Experience from performance testing of low NOx burners for refinery heaters; Tests de performance avec des bruleurs de raffinerie a basse emission de NOx

    Energy Technology Data Exchange (ETDEWEB)

    Boden, J.C. [Refining Technology, BP Oil International, Sunbury (United Kingdom)

    2001-07-01

    Developments in low NOx burner technology have resulted in major reductions in NOx emissions from refinery process heaters. However, the techniques used in low NOx burners to reduce NOx emissions can potentially affect other key aspects of burner performance, particularly flame stability and completeness of combustion. BP has evaluated many of the currently available low and ultra-low NOx burners, both natural and forced draught, in its purpose-built test furnace. This extensive test programme has shown that to be a reliable predictor of actual performance a test rig must recreate accurately the real furnace conditions, particularly with respect to furnace and hearth temperatures. The testing has demonstrated the NOx emissions to be expected in practice from different generic types of burner, conventional, low NOx and ultra-low NOx, and has highlighted the sets of conditions most likely to lead to combustion performance problems. (authors)

  9. THE STATISTICS OF ALBEDO AND HEAT RECIRCULATION ON HOT EXOPLANETS

    International Nuclear Information System (INIS)

    Cowan, Nicolas B.; Agol, Eric

    2011-01-01

    If both the day-side and night-side effective temperatures of a planet can be measured, it is possible to estimate its Bond albedo, 0 B 0 , and associated uncertainty. We then use a simple model-independent technique to estimate a planet's effective temperature from planet/star flux ratios. We use thermal secondary eclipse measurements-those obtained at λ>0.8 μm-to estimate day-side effective temperatures, T d , and thermal phase variations-when available-to estimate night-side effective temperature. We strongly rule out the 'null hypothesis' of a single A B and ε for all 24 planets. If we allow each planet to have different parameters, we find that low Bond albedos are favored (A B 0 , the day-side effective temperatures of the 24 planets describe a uni-modal distribution. The two biggest outliers are GJ 436b (abnormally hot) and HD 80606b (abnormally cool), and these are the only eccentric planets in our sample. The dimensionless quantity T d /T 0 exhibits no trend with the presence or absence of stratospheric inversions. There is also no clear trend between T d /T 0 and T 0 . That said, the six planets with the greatest sub-stellar equilibrium temperatures (T > 2400 K) have low ε, as opposed to the 18 cooler planets, which show a variety of recirculation efficiencies. This hints that the very hottest transiting giant planets are qualitatively different from the merely hot Jupiters. We propose an explanation of this trend based on how a planet's radiative and advective times scale with temperature: both timescales are expected to be shorter for hotter planets, but the temperature dependence of the radiative timescale is stronger, leading to decreased heat recirculation efficiency.

  10. The Statistics of Albedo and Heat Recirculation on Hot Exoplanets

    Science.gov (United States)

    Cowan, Nicolas B.; Agol, Eric

    2011-03-01

    If both the day-side and night-side effective temperatures of a planet can be measured, it is possible to estimate its Bond albedo, 0 calculate a sub-stellar equilibrium temperature, T 0, and associated uncertainty. We then use a simple model-independent technique to estimate a planet's effective temperature from planet/star flux ratios. We use thermal secondary eclipse measurements—those obtained at λ>0.8 μm—to estimate day-side effective temperatures, T d, and thermal phase variations—when available—to estimate night-side effective temperature. We strongly rule out the "null hypothesis" of a single AB and ɛ for all 24 planets. If we allow each planet to have different parameters, we find that low Bond albedos are favored (AB outliers are GJ 436b (abnormally hot) and HD 80606b (abnormally cool), and these are the only eccentric planets in our sample. The dimensionless quantity T d/T 0 exhibits no trend with the presence or absence of stratospheric inversions. There is also no clear trend between T d/T 0 and T 0. That said, the six planets with the greatest sub-stellar equilibrium temperatures (T > 2400 K) have low ɛ, as opposed to the 18 cooler planets, which show a variety of recirculation efficiencies. This hints that the very hottest transiting giant planets are qualitatively different from the merely hot Jupiters. We propose an explanation of this trend based on how a planet's radiative and advective times scale with temperature: both timescales are expected to be shorter for hotter planets, but the temperature dependence of the radiative timescale is stronger, leading to decreased heat recirculation efficiency.

  11. Recirculation of the Canary Current in fall 2014

    Science.gov (United States)

    Hernández-Guerra, Alonso; Espino-Falcón, Elisabet; Vélez-Belchí, Pedro; Dolores Pérez-Hernández, M.; Martínez-Marrero, Antonio; Cana, Luis

    2017-10-01

    Hydrographic measurements together with Ship mounted Acoustic Doppler Current Profilers and Lowered Acoustic Doppler Current Profilers (LADCP) obtained in October 2014 are used to describe water masses, geostrophic circulation and mass transport of the Canary Current System, as the Eastern Boundary of the North Atlantic Subtropical Gyre. Geostrophic velocities are adjusted to velocities from LADCP data to estimate an initial velocity at the reference layer. The adjustment results in a northward circulation at the thermocline layers over the African slope from an initial convergent flow. Final reference velocities and consequently absolute circulation are estimated from an inverse box model applied to an ocean divided into 13 neutral density layers. This allows us to evaluate mass fluxes consistent with the thermal wind equation and mass conservation. Ekman transport is estimated from the wind data derived from the Weather Research and Forecasting model. Ekman transport is added to the first layer and adjusted with the inverse model. The Canary Current located west of Lanzarote Island transports to the south a mass of - 1.5 ± 0.7 Sv (1 Sv = 106 m3 s- 1 ≈ 109 kg s- 1) of North Atlantic Central Water at the surface and thermocline layers ( 0-700 m). In fall 2014, hydrographic data shows that the Canary Current in the thermocline (below at about 80 m depth to 700 m) recirculates to the north over the African slope and flows through the Lanzarote Passage. At intermediate layers ( 700-1400 m), the Intermediate Poleward Undercurrent transports northward a relatively fresh Antarctic Intermediate Water in the range of 0.8 ± 0.4 Sv through the Lanzarote Passage and west of Lanzarote Island beneath the recirculation of the Canary Current.

  12. NO_x reduction and N_2O emissions in a diesel engine exhaust using Fe-zeolite and vanadium based SCR catalysts

    International Nuclear Information System (INIS)

    Cho, Chong Pyo; Pyo, Young Dug; Jang, Jin Young; Kim, Gang Chul; Shin, Young Jin

    2017-01-01

    Highlights: • NO_x reduction and N_2O emission of urea-SCR catalysts with the oxidation precatalysts were investigated. • Fe-zeolite and V-based catalysts were noticeably affected by the NO_2/NOx ratio. • Remarkable N_2O formation was observed only for the Fe-zeolite catalyst. - Abstract: Among various approaches used to comply with strict diesel engine exhaust regulations, there is increasing interest in urea based selective catalytic reduction (SCR) as a NO_x reduction technology, due to its high reduction and excellent fuel efficiencies. NO_x reduction by SCR catalysts is affected by variations in the NO_2/NO_x ratio, caused by oxidation catalysts such as the diesel oxidation catalyst (DOC) and diesel particulate filter (DPF) installed in diesel engines. Recently, it has been reported that the greenhouse gas (GHG) variant N_2O, which is a by-product of the NO_x conversion process in the after-treatment system, will be subject to regulation. Using a real diesel engine installed with DOC and DPF, the NO_x reduction and N_2O emission performances of commonly used Fe-zeolite and V_2O_5-WO_3/TiO_2 catalysts were investigated under various operating conditions. The exhaust of the diesel engine used in this study had a NO_2/NO_x ratio of over 50% for temperatures below 400 °C due to the oxidation catalysts, while the NO_2/NO_x ratio was significantly lower for temperatures above 400 °C. Under such conditions, it was found that the Fe-zeolite and V_2O_5-WO_3/TiO_2 catalysts were noticeably affected by the NO_2/NOx ratio and exhaust temperature. Although both catalysts showed satisfactory NO conversions, the V_2O_5-WO_3/TiO_2 catalyst showed decreasing NO_2 conversion rates between 250 °C and 320 °C. The V_2O_5-WO_3/TiO_2 catalyst exhibited NH_3 slip relatively frequently because of its low NH_3 storage capacity. For the Fe-zeolite catalyst, a significant increase in the amount of generated N_2O was observed for high NO_x conversion conditions due to side

  13. 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

  14. Both cardiomyocyte and endothelial cell Nox4 mediate protection against hemodynamic overload-induced remodelling.

    Science.gov (United States)

    Zhang, Min; Mongue-Din, Heloise; Martin, Daniel; Catibog, Norman; Smyrnias, Ioannis; Zhang, Xiaohong; Yu, Bin; Wang, Minshu; Brandes, Ralf P; Schröder, Katrin; Shah, Ajay M

    2018-03-01

    NADPH oxidase-4 (Nox4) is an important reactive oxygen species (ROS) source that is upregulated in the haemodynamically overloaded heart. Our previous studies using global Nox4 knockout (Nox4KO) mice demonstrated a protective role of Nox4 during chronic abdominal aortic banding, involving a paracrine enhancement of myocardial capillary density. However, other authors who studied cardiac-specific Nox4KO mice reported detrimental effects of Nox4 in response to transverse aortic constriction (TAC). It has been speculated that these divergent results are due to cell-specific actions of Nox4 (i.e. cardiomyocyte Nox4 detrimental but endothelial Nox4 beneficial) and/or differences in the model of pressure overload (i.e. abdominal banding vs. TAC). This study aimed to (i) investigate whether the effects of Nox4 on pressure overload-induced cardiac remodelling vary according to the pressure overload model and (ii) compare the roles of cardiomyocyte vs. endothelial cell Nox4. Global Nox4KO mice subjected to TAC developed worse cardiac remodelling and contractile dysfunction than wild-type littermates, consistent with our previous results with abdominal aortic banding. Next, we generated inducible cardiomyocyte-specific Nox4 KO mice (Cardio-Nox4KO) and endothelial-specific Nox4 KO mice (Endo-Nox4KO) and studied their responses to pressure overload. Both Cardio-Nox4KO and Endo-Nox4KO developed worse pressure overload-induced cardiac remodelling and dysfunction than wild-type littermates, associated with significant decrease in protein levels of HIF1α and VEGF and impairment of myocardial capillarization. Cardiomyocyte as well as endothelial cell Nox4 contributes to protection against chronic hemodynamic overload-induced cardiac remodelling, at least in part through common effects on myocardial capillary density. © The Author 2017 Published by Oxford University Press on behalf of the European Society of Cardiology.

  15. Reaction phenomena of catalytic partial oxidation of methane under the impact of carbon dioxide addition and heat recirculation

    International Nuclear Information System (INIS)

    Chen, Wei-Hsin; Lin, Shih-Cheng

    2015-01-01

    The reaction phenomena of CPOM (catalytic partial oxidation of methane) in a Swiss-roll reactor are studied numerically where a rhodium-based catalyst bed is embedded at the center of the reactor. CO 2 is added into the feed gas and excess enthalpy recovery is performed to evaluate their influences on CPOM performance. In the study, the mole ratio of O 2 to CH 4 (O 2 /CH 4 ratio) is fixed at 0.5 and the mole ratio of CO 2 to O 2 (CO 2 /O 2 ratio) is in the range of 0–2. The results reveal that CO 2 addition into the influent has a slight effect on methane combustion, but significantly enhances dry reforming and suppresses steam reforming. The reaction extents of steam reforming and dry reforming in CPOM without heat recovery and CO 2 addition are in a comparable state. Once CO 2 is added into the feed gas, the dry reforming is enhanced, thereby dominating CH 4 consumption. Compared to the reactor without excess enthalpy recovery, heat recirculation drastically increases the maximum reaction temperature and CH 4 conversion in the catalyst bed; it also intensifies the H 2 selectivity, H 2 yield, CO 2 conversion, and syngas production rate. The predictions indicate that the heat recirculation is able to improve the syngas formation up to 45%. - Highlights: • Catalytic partial oxidation of methane with CO 2 addition and heat recovery is studied. • CO 2 addition has a slight effect on methane combustion. • CO 2 addition significantly enhances dry reforming and suppresses steam reforming. • Dry reforming dominates CH 4 consumption when CO 2 addition is large. • Heat recirculation can improve the syngas formation up to 45%

  16. Sulfur recirculation for increased electricity production in Waste-to-Energy plants.

    Science.gov (United States)

    Andersson, Sven; Blomqvist, Evalena W; Bäfver, Linda; Jones, Frida; Davidsson, Kent; Froitzheim, Jan; Karlsson, Martin; Larsson, Erik; Liske, Jesper

    2014-01-01

    Sulfur recirculation is a new technology for reducing boiler corrosion and dioxin formation. It was demonstrated in full-scale tests at a Waste to Energy plant in Göteborg (Sweden) during nearly two months of operation. Sulfur was recirculated as sulfuric acid from the flue gas cleaning back to the boiler, thus creating a sulfur loop. The new technology was evaluated by extensive measurement campaigns during operation under normal conditions (reference case) and operation with sulfur recirculation. The chlorine content of both fly ash and boiler ash decreased and the sulfur content increased during the sulfur recirculation tests. The deposit growth and the particle concentration decreased with sulfur recirculation and the dioxin concentration (I-TEQ) of the flue gas was reduced by approximately 25%. Sulfuric acid dew point measurements showed that the sulfuric acid dosage did not lead to elevated SO3 concentrations, which may otherwise induce low temperature corrosion. In the sulfur recirculation corrosion probe exposures, the corrosion rate decreased for all tested materials (16Mo3, Sanicro 28 and Inconel 625) and material temperatures (450 °C and 525 °C) compared to the reference exposure. The corrosion rates were reduced by 60-90%. Sulfur recirculation prevented the formation of transition metal chlorides at the metal/oxide interface, formation of chromate and reduced the presence of zinc in the corrosion products. Furthermore, measured corrosion rates at 525 °C with sulfur recirculation in operation were similar or lower compared to those measured at 450 °C material temperature in reference conditions, which corresponds to normal operation at normal steam temperatures. This implies that sulfur recirculation allows for higher steam data and electricity production without increasing corrosion. Copyright © 2013 The Authors. Published by Elsevier Ltd.. All rights reserved.

  17. Impact of NOx and OH on secondary organic aerosol formation from β-pinene photooxidation

    Directory of Open Access Journals (Sweden)

    M. Sarrafzadeh

    2016-09-01

    Full Text Available In this study, the NOx dependence of secondary organic aerosol (SOA formation from photooxidation of the biogenic volatile organic compound (BVOC β-pinene was comprehensively investigated in the Jülich Plant Atmosphere Chamber. Consistent with the results of previous NOx studies we found increases of SOA yields with increasing [NOx] at low-NOx conditions ([NOx]0  <  30 ppb, [BVOC]0 ∕ [NOx]0  >  10 ppbC ppb−1. Furthermore, increasing [NOx] at high-NOx conditions ([NOx]0  >  30 ppb, [BVOC]0 ∕ [NOx]0  ∼  10 to  ∼  2.6 ppbC ppb−1 suppressed the SOA yield. The increase of SOA yield at low-NOx conditions was attributed to an increase of OH concentration, most probably by OH recycling in NO + HO2  →  NO2 + OH reaction. Separate measurements without NOx addition but with different OH primary production rates confirmed the OH dependence of SOA yields. After removing the effect of OH concentration on SOA mass growth by keeping the OH concentration constant, SOA yields only decreased with increasing [NOx]. Measuring the NOx dependence of SOA yields at lower [NO] ∕ [NO2] ratio showed less pronounced increase in both OH concentration and SOA yield. This result was consistent with our assumption of OH recycling by NO and to SOA yields being dependent on OH concentrations. Our results furthermore indicated that NOx dependencies vary for different NOx compositions. A substantial fraction of the NOx-induced decrease of SOA yields at high-NOx conditions was caused by NOx-induced suppression of new particle formation (NPF, which subsequently limits the particle surface where low volatiles condense. This was shown by probing the NOx dependence of SOA formation in the presence of seed particles. After eliminating the effect of NOx-induced suppression of NPF and NOx-induced changes of OH concentrations, the remaining effect of NOx on the SOA yield from

  18. Intracellular expression of reactive oxygen species-generating NADPH oxidase NOX4 in normal and cancer thyroid tissues

    NARCIS (Netherlands)

    Weyemi, Urbain; Caillou, Bernard; Talbot, Monique; Ameziane-El-Hassani, Rabii; Lacroix, Ludovic; Lagent-Chevallier, Odile; Al Ghuzlan, Abir; Roos, Dirk; Bidart, Jean-Michel; Virion, Alain; Schlumberger, Martin; Dupuy, Corinne

    2010-01-01

    NADPH oxidase 4 (NOX4) belongs to the NOX family that generates reactive oxygen species (ROS). Function and tissue distribution of NOX4 have not yet been entirely clarified. To date, in the thyroid gland, only DUOX1/2 NOX systems have been described. NOX4 mRNA expression, as shown by real-time PCR,

  19. Boiler recirculation pumps for nuclear power stations - present state of development. Directions for planning, operational experience

    International Nuclear Information System (INIS)

    Mattias, H.B.

    1976-01-01

    Boiler recirculation pumps are important components of modern power stations. The development of large recirculation pumps up to a driving power of 1,500 kW was faced with some problems in meeting the plant requirements. In this paper, the present state of development is dealt with. The development problems in the fields of hydrodynamics, cavitation, corrosion and erosion are dealt with as well as the problems of the design of the casing with regard to thermodynamics and strength. Finally, operational experience with the boiler recirculation pump for 600 MW power stations will be reported on. (orig./AK) [de

  20. Emission and performance analysis on the effect of exhaust gas recirculation in alcohol-biodiesel aspirated research diesel engine.

    Science.gov (United States)

    Mahalingam, Arulprakasajothi; Munuswamy, Dinesh Babu; Devarajan, Yuvarajan; Radhakrishnan, Santhanakrishnan

    2018-05-01

    In this study, the effect of blending pentanol to biodiesel derived from mahua oil on emissions and performance pattern of a diesel engine under exhaust gas recirculation (EGR) mode was examined and compared with diesel. The purpose of this study is to improve the feasibility of employing biofuels as a potential alternative in an unmodified diesel engine. Two pentanol-biodiesel blends denoted as MOBD90P10 and MOBD80P20 which matches to 10 and 20 vol% of pentanol in biodiesel, respectively, were used as fuel in research engine at 10 and 20% EGR rates. Pentanol is chosen as a higher alcohol owing to its improved in-built properties than the other first-generation alcohols such as ethanol or methanol. Experimental results show that the pentanol and biodiesel blends (MOBD90P10 and MOBD80P20) have slightly higher brake thermal efficiency (0.2-0.4%) and lower brake-specific fuel consumption (0.6 to 1.1%) than that of neat biodiesel (MOBD100) at all engine loads. Nitrogen oxide (NOx) emission and smoke emission are reduced by 3.3-3.9 and 5.1-6.4% for pentanol and biodiesel blends compared to neat biodiesel. Introduction of pentanol to biodiesel reduces the unburned hydrocarbon (2.1-3.6%) and carbon monoxide emissions (3.1-4.2%) considerably. In addition, at 20% EGR rate, smoke, NO X emissions, and BTE drop by 7.8, 5.1, and 4.4% respectively. However, CO, HC emissions, and BSFC increased by 2.1, 2.8, and 3.8%, respectively, when compared to 0% EGR rate.

  1. Surrogate Model for Recirculation Phase LBLOCA and DET Application

    International Nuclear Information System (INIS)

    Fynan, Douglas A; Ahn, Kwang-Il; Lee, John C.

    2014-01-01

    In the nuclear safety field, response surfaces were used in the first demonstration of the code scaling, applicability, and uncertainty (CSAU) methodology to quantify the uncertainty of the peak clad temperature (PCT) during a large-break loss-of-coolant accident (LBLOCA). Surrogates could have applications in other nuclear safety areas such as dynamic probabilistic safety assessment (PSA). Dynamic PSA attempts to couple the probabilistic nature of failure events, component transitions, and human reliability to deterministic calculations of time-dependent nuclear power plant (NPP) responses usually through the use of thermal-hydraulic (TH) system codes. The overall mathematical complexity of the dynamic PSA architectures with many embedded computational expensive TH code calculations with large input/output data streams have limited realistic studies of NPPs. This paper presents a time-dependent surrogate model for the recirculation phase of a hot leg LBLOCA in the OPR-1000. The surrogate model is developed through the ACE algorithm, a powerful nonparametric regression technique, trained on RELAP5 simulations of the LBLOCA. Benchmarking of the surrogate is presented and an application to a simplified dynamic event tree (DET). A time-dependent surrogate model to predict core subcooling during the recirculation phase of a hot leg LBLOCA in the OPR-1000 has been developed. The surrogate assumed the structure of a general discrete time dynamic model and learned the nonlinear functional form by performing nonparametric regression on RELAP5 simulations with the ACE algorithm. The surrogate model input parameters represent mass and energy flux terms to the RCS that appeared as user supplied or code calculated boundary conditions in the RELAP5 model. The surrogate accurately predicted the TH behavior of the core for a variety of HPSI system performance and containment conditions when compared with RELAP5 simulations. The surrogate was applied in a DET application replacing

  2. Recirculation, stagnation and ventilation: The 2014 legionella episode

    Science.gov (United States)

    Russo, Ana; Soares, Pedro M. M.; Gouveia, Célia M.; Cardoso, Rita M.; Trigo, Ricardo M.

    2017-04-01

    Legionella transmission through the atmosphere is unusual, but not unprecedented. A scientific paper published in 2006 reports a surge in Pas-de-Calais, France, in which 86 people have been infected by bacteria released by a cooling tower more than 6 km away [3]. Similarly, in Norway, in 2005, there was another case where contamination spread beyond 10 km, although more concentrated within a radius of 1 km from an industrial unit [2]. An unprecedented large Legionella outbreak occurred in November 2014 nearby Lisbon, Portugal. As of 7 November 2014, 375 individuals become hill and 12 died infected by the Legionella pneumophila bacteria, contracted by inhalation of steam droplets of contaminated water (aerosols). These droplets are so small that can carry the bacteria directly to the lungs, depositing it in the alveoli. One way of studying the propagation of legionella episodes is through the use of aerosol dispersion models. However, such approaches often require detailed 3D high resolution wind data over the region, which isn't often available for long periods. The likely impact of wind on legionella transmission can also be understood based on the analysis of special types of flow conditions such as stagnation, recirculation and ventilation [1, 4]. The Allwine and Whiteman (AW) approach constitutes a straightforward method to assess the assimilative and dispersal capacities of different airsheds [1,4], as it only requires hourly wind components. Thus, it has the advantage of not needing surface and upper air meteorological observations and a previous knowledge of the atmospheric transport and dispersion conditions. The objective of this study is to analyze if the legionella outbreak event which took place in November 2014 had extreme potential recirculation and/or stagnation characteristics. In order to accomplish the proposed objective, the AW approach was applied for a hindcast time-series covering the affected area (1989-2007) and then for an independent

  3. Comparison of biocides for disinfection treatment of open recirculating cooling circuits

    International Nuclear Information System (INIS)

    Soreau, Sylvie; Prisset, Frederic; Carvajal, Nathalie

    2012-09-01

    Open recirculating cooling circuits of nuclear power plants are likely to face pathogenic proliferations like Legionella and amoebae (Naegleria fowleri). To reduce such risks, biocide treatments are usually implemented. However, the selection of a treatment is never easy due to the large size of the cooling circuits. Indeed, the range of treatment options is limited due to potential health or environmental impacts of chemicals in case of chemical treatments or because of the technical difficulties to implement treatment units appropriate to the size of the cooling circuits in case of physical treatments. In the aim of finding the best compromise between efficacy, nature and quantity of chemical releases and industrial feasibility, several biocide treatments were compared at lab and pilot scale using semi-industrial pilot plants simulating recirculating cooling circuit of a nuclear power plant. These pilots were fed with river water or pre-treated water (lime softening or clari-flocculation). They were equipped with materials and surfaces representative of those found on a full-scale plant. These pilots operated at summer temperatures favoring microbial growth. Three industrial biocides were compared: chlorine, monochloramine and chlorine dioxide. The results indicate that the transit in the cooling system strongly affects the consumption of biocides and therefore their efficacy, the quantity of biocide needed and chemical releases so that the ranking of treatments defined on the basis of laboratory tests can be strongly modified. The results show different areas of consumption along the process line depending on biocides and highlight the significant role of the cooling tower. The behavior of biocides in the different compartments of the circuit (cooling tower, condenser, basins) is described and the consequences on pathogenic micro-organisms removal in bio-films and on chemical releases are considered as function of the studied biocide. Moreover, the influence of

  4. 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)

  5. 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.

  6. Further studies on beam breakup growth reduction by cavity cross-couplings in recirculating accelerators: Effects of long pulse length and multiturn recirculation

    International Nuclear Information System (INIS)

    Colombant, D.; Lau, Y.Y.

    1992-01-01

    Cavity cross-coupling was recently found to reduce beam breakup (BBU) growth in a recirculating accelerator known as the Spiral Line Induction Accelerator (SLIA). Here, we extend the analysis in two prespects: ong beam pulse lengths and a SLIA upgrade geometry which accelerates a 10 kA, 35 ns beam to 25 MeV via a 70 cavity, 7 turn recirculation. We found that when the beam pulse length τ exceeds the beam's transit time τ' between cross-coupled cavities, BBU growth may be worsened as a result of the cross-coupling among cavities. This situation is not unlike other long pulse recirculating accelerators where beam recirculation leads to beam breakup of a regenerative type. Thus, the advantage of BBU reduction by cavity cross-coupling is restricted primarily to beams with τ<τ', a condition envisioned for all SLIA geometries. For the 70 gap, 7 turn SLIA upgrade, we found that cavity cross-coupling may reduce BBU growth up to factors of a thousand when the quality factor Q of the deflecting modes are relatively high (like 100). In these high Q cases, the amount of growth reduction depends on the arrangement and sequence of beam recirculation. For Q < or approx. 20, BBU growth reduction by factors of hundreds is observed, but this reduction is insensitive to the sequence of beam recirculation. The above conclusions were based on simple models of cavity coupling that have been used in conventional microwave literature. Not addressed is the detail design consideration that leads to the desired degree of cavity coupling. (orig.)

  7. 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.

  8. Effect of increasing salinity on biogas production in waste landfills with leachate recirculation: A lab-scale model study

    Directory of Open Access Journals (Sweden)

    Yuka Ogata

    2016-06-01

    Full Text Available The effects of salinity on anaerobic waste degradation and microbial communities were investigated, in order to propose an appropriate leachate recirculation process in a waste landfill in a tropical region. A salt concentration of 21 mS cm−1 of electrical conductivity (EC did not affect waste degradation, but a salt concentration of 35 mS cm−1 of EC inhibited CH4 generation. A higher salt concentration of 80 mS cm−1 of EC inhibited not only CH4 and CO2 generation, but also degradation of organic compounds. The bacterial and archaeal community compositions were affected by high salinity. High salinity can exert selective pressure on bacterial communities, resulting in a change in bacterial community structure. Ammonium caused strong, dominant inhibition of biogas production in the salt concentration range of this study. Quality control, especially of ammonium levels, will be essential for the promotion of waste biodegradation in landfills with leachate recirculation.

  9. Recirculating aquaculture production systems : an overview of different components, management, economics and technology

    NARCIS (Netherlands)

    Kals, J.

    2004-01-01

    Report of a literature study on Recirculating aquaculture production systems executed within the MRG ercirculation program. The report gives an overview of different components, management, economics and technology and is made by the Netherlands Institute for Fisheries Research (RIVO).

  10. Characterising organic matter in recirculating aquaculture systems with fluorescence EEM spectroscopy

    DEFF Research Database (Denmark)

    Hambly, Adam; Arvin, Erik; Pedersen, Lars-Flemming

    2015-01-01

    The potential of recirculating aquaculture systems (RAS) in the aquaculture industry is increasingly being acknowledged. Along with intensified application, the need to better characterise and understand the accumulated dissolved organic matter (DOM) within these systems increases. Mature RASs...

  11. Mechanical design of recirculating accelerator experiments for heavy-ion fusion

    International Nuclear Information System (INIS)

    Karpenko, V.

    1995-01-01

    Recirculating induction accelerators have been studied as a potential low cost driver for inertial fusion energy. At LLNL, we are developing a small (4.5-m diameter), scaled, experimental machine which will demonstrate many of the engineering solutions of a full scale driver. The small recirculator will accelerate singly ionized potassium ions from 80 to 320 keV and 2 to 8 mA, using electric dipoles for bending and permanent magnet quadrupoles for focusing in a compact periodic lattice. While very compact, and low cost, this design allows the investigation of most of the critical physics issues associated with space-charge-dominated beams in future IFE power plant drivers. This report describes the recirculator, its mechanical design, its vacuum design, and the process for aligning it. Additionally, a straight magnetic transport experiment is being carried out to test diagnostics and magnetic transport in preparation for the recirculator

  12. Dietary carbohydrate composition can change waste production and biofilter load in recirculating aquaculture systems

    NARCIS (Netherlands)

    Meriac, A.; Eding, E.H.; Schrama, J.W.; Kamstra, A.; Verreth, J.A.J.

    2014-01-01

    This study investigated the effect of dietary carbohydrate composition on the production, recovery and degradability of fecal waste from rainbow trout (Oncorhynchus mykiss) in recirculating aquaculture systems (RAS). Dietary carbohydrate composition was altered by substituting starch with non-starch

  13. Optimization of recirculating laminar air flow in operating room air conditioning systems

    Directory of Open Access Journals (Sweden)

    Enver Yalcin

    2016-04-01

    Full Text Available The laminar flow air-conditioning system with 100% fresh air is used in almost all operating rooms without discrimination in Turkey. The laminar flow device which is working with 100% fresh air should be absolutely used in Type 1A operating rooms. However, there is not mandatory to use of 100% fresh air for Type 1B defined as places performed simpler operation. Compared with recirculating laminar flow, energy needs of the laminar flow with 100 % fresh air has been emerged about 40% more than re-circulated air flow. Therefore, when a recirculating laminar flow device is operated instead of laminar flow system with 100% fresh air in the Type 1B operating room, annual energy consumption will be reduced. In this study, in an operating room with recirculating laminar flow, optimal conditions have been investigated in order to obtain laminar flow form by analyzing velocity distributions at various supply velocities by using computational fluid dynamics method (CFD.

  14. Vortex dynamics in a pipe T-junction: Recirculation and sensitivity

    Science.gov (United States)

    Chen, Kevin K.; Rowley, Clarence W.; Stone, Howard A.

    2015-03-01

    In the last few years, many researchers have noted that regions of recirculating flow often exhibit particularly high sensitivity to spatially localized feedback. We explore the flow through a T-shaped pipe bifurcation—a simple and ubiquitous, but generally poorly understood flow configuration—and provide a complex example of the relation between recirculation and sensitivity. When Re ≥ 320, a phenomenon resembling vortex breakdown occurs in four locations in the junction, with internal stagnation points appearing on vortex axes and causing flow reversal. The structure of the recirculation is similar to the traditional bubble-type breakdown. These recirculation regions are highly sensitive to spatially localized feedback in the linearized Navier-Stokes operator. The flow separation at the corners of the "T," however, does not exhibit this kind of sensitivity. We focus our analysis on the Reynolds number of 560, near the first Hopf bifurcation of the flow.

  15. Aircraft Recirculation Filter for Air-Quality and Incident Assessment

    Science.gov (United States)

    Eckels, Steven J.; Jones, Byron; Mann, Garrett; Mohan, Krishnan R.; Weisel, Clifford P.

    2015-01-01

    The current research examines the possibility of using recirculation filters from aircraft to document the nature of air-quality incidents on aircraft. These filters are highly effective at collecting solid and liquid particulates. Identification of engine oil contaminants arriving through the bleed air system on the filter was chosen as the initial focus. A two-step study was undertaken. First, a compressor/bleed air simulator was developed to simulate an engine oil leak, and samples were analyzed with gas chromatograph-mass spectrometry. These samples provided a concrete link between tricresyl phosphates and a homologous series of synthetic pentaerythritol esters from oil and contaminants found on the sample paper. The second step was to test 184 used aircraft filters with the same gas chromatograph-mass spectrometry system; of that total, 107 were standard filters, and 77 were nonstandard. Four of the standard filters had both markers for oil, with the homologous series synthetic pentaerythritol esters being the less common marker. It was also found that 90% of the filters had some detectable level of tricresyl phosphates. Of the 77 nonstandard filters, 30 had both markers for oil, a significantly higher percent than the standard filters. PMID:25641977

  16. Aircraft Recirculation Filter for Air-Quality and Incident Assessment.

    Science.gov (United States)

    Eckels, Steven J; Jones, Byron; Mann, Garrett; Mohan, Krishnan R; Weisel, Clifford P

    The current research examines the possibility of using recirculation filters from aircraft to document the nature of air-quality incidents on aircraft. These filters are highly effective at collecting solid and liquid particulates. Identification of engine oil contaminants arriving through the bleed air system on the filter was chosen as the initial focus. A two-step study was undertaken. First, a compressor/bleed air simulator was developed to simulate an engine oil leak, and samples were analyzed with gas chromatograph-mass spectrometry. These samples provided a concrete link between tricresyl phosphates and a homologous series of synthetic pentaerythritol esters from oil and contaminants found on the sample paper. The second step was to test 184 used aircraft filters with the same gas chromatograph-mass spectrometry system; of that total, 107 were standard filters, and 77 were nonstandard. Four of the standard filters had both markers for oil, with the homologous series synthetic pentaerythritol esters being the less common marker. It was also found that 90% of the filters had some detectable level of tricresyl phosphates. Of the 77 nonstandard filters, 30 had both markers for oil, a significantly higher percent than the standard filters.

  17. Muon catalyzed fusion - fission reactor driven by a recirculating beam

    International Nuclear Information System (INIS)

    Eliezer, S.; Tajima, T.; Rosenbluth, M.N.

    1986-01-01

    The recent experimentally inferred value of multiplicity of fusion of deuterium and tritium catalyzed by muons has rekindled interest in its application to reactors. Since the main energy expended is in pion (and consequent muon) productions, we try to minimize the pion loss by magnetically confining pions where they are created. Although it appears at this moment not possible to achieve energy gain by pure fusion, it is possible to gain energy by combining catalyzed fusion with fission blankets. We present two new ideas that improve the muon fusion reactor concept. The first idea is to combine the target, the converter of pions into muons, and the synthesizer into one (the synergetic concept). This is accomplished by injecting a tritium or deuterium beam of 1 GeV/nucleon into DT fuel contained in a magnetic mirror. The confined pions slow down and decay into muons, which are confined in the fuel causing little muon loss. The necessary quantity of tritium to keep the reactor viable has been derived. The second idea is that the beam passing through the target is collected for reuse and recirculated, while the strongly interacted portion of the beam is directed to electronuclear blankets. The present concepts are based on known technologies and on known physical processes and data. 29 refs., 6 figs., 4 tabs

  18. Particle recirculation in the ergodic divertor of Tore Supra

    International Nuclear Information System (INIS)

    Gunn, J.P.; Azeoual, A.; Becoulet, M.

    1999-01-01

    The present paper addresses the issue of particle recirculation in discharges where low energy flux to ergodic divertor target plates is achieved, in highly radiating detached ohmic plasmas. Plasma temperature and particle flux are measured by flush-mounted probes in the divertor plates, and by an upstream fast scanning Mach probe. The scalings with core density of the ion flux and electron temperature are well described by the simple two-point model used in axisymmetric poloidal divertors. The detachment signature is a pressure drop that occurs when the edge temperature falls below 10 eV. The parallel ion flux gradient is always positive, indicating that recombination is unlikely to play an important role in detachment. Visible spectroscopy of a neutralizer plate shows that attainment of cold detached plasmas near the density limit coincides with an abrupt increase of fueling for both deuterium and impurities. A feedback algorithm based on real time Langmuir probe measurements has been developed to monitor detachment and avoid disruptions. (authors)

  19. Design of a High-Reynolds Number Recirculating Water Tunnel

    Science.gov (United States)

    Daniel, Libin; Elbing, Brian

    2014-11-01

    An experimental fluid mechanics laboratory focused on turbulent boundary layers, drag reduction techniques, multiphase flows and fluid-structure interactions has recently been established at Oklahoma State University. This laboratory has three primary components; (1) a recirculating water tunnel, (2) a multiphase pipe flow loop, and (3) a multi-scale flow visualization system. The design of the water tunnel is the focus of this talk. The criteria used for the water tunnel design was that it had to produce a momentum-thickness based Reynolds number in excess of 104, negligible flow acceleration due to boundary layer growth, maximize optical access for use of the flow visualization system, and minimize inlet flow non-uniformity. This Reynolds number was targeted to bridge the gap between typical university/commercial water tunnels (103) and the world's largest water tunnel facilities (105) . These objectives were achieved with a 152 mm (6-inch) square test section that is 1 m long and has a maximum flow speed of 10 m/s. The flow non-uniformity was mitigated with the use of a tandem honeycomb configuration, a settling chamber and an 8.5:1 contraction. The design process that produced this final design will be presented along with its current status.

  20. Comparison of recirculation configurations for biological nutrient removal in a membrane bioreactor.

    Science.gov (United States)

    Bekir Ersu, Cagatayhan; Ong, Say Kee; Arslankaya, Ertan; Brown, Patrick

    2008-03-01

    A 12-L lab-scale membrane bioreactor (MBR), consisting of an anaerobic and anoxic compartment followed by an oxic plate-frame membrane compartment, was evaluated for carbonaceous and nutrient removals by varying the recirculation of mixed liquor and permeate. The hydraulic retention times (HRTs) for the anaerobic, anoxic, and oxic compartments were 2, 2, and 8h, respectively. The solids residence time (SRT) for the oxic compartment was 25 days. Five different recirculation configurations were tested by recirculating mixed liquor and/or permeate recirculation equal to the influent flow rate (identified as 100%) into different locations of the anaerobic and anoxic compartments. Of the five configurations, the configuration with 100% mixed liquor recirculation to the anaerobic compartment and 100% permeate recirculation to the anoxic compartment gave the highest percentage removal with an average 92.3+/-0.5% soluble chemical oxygen demand (sCOD), 75.6+/-0.4% total nitrogen (TN), and 62.4+/-1.3% total phosphorus (TP) removal. When the mixed liquor and permeate recirculation rates were varied for the same configuration, the highest TP removal was obtained for 300% mixed liquor recirculation and 100% permeate recirculation (300%/100%) with a TP removal of 88.1+/-1.3% while the highest TN removal (90.3+/-0.3%) was obtained for 200%/300% recirculation. TN and TP concentrations as low as 4.2+/-0.1 and 1.4+/-0.2mg/L respectively were obtained. Mass loading rates were generally low in the range of 0.11-0.22kgCOD/kgMLSS/d due to high biomass concentrations within the oxic reactor (approx. 8000mg/L). The BioWin model was calibrated against one set of the experimental data and was found to predict the experimental data of effluent TN, TP, and NO(3)(-)-N but over-predicted sCOD and NH(3)-N for various recirculation rates. The anoxic heterotrophic yield for the calibrated model was 0.2kg biomass COD/kg COD utilized while the maximum growth rates were found to be 0.45day(-1) for mu

  1. Maritime NOx Emissions Over Chinese Seas Derived From Satellite Observations

    Science.gov (United States)

    Ding, J.; van der A, R. J.; Mijling, B.; Jalkanen, J.-P.; Johansson, L.; Levelt, P. F.

    2018-02-01

    By applying an inversion algorithm to NOx satellite observations from Ozone Monitoring Instrument, monthly NOx emissions for a 10 year period (2007 to 2016) over Chinese seas are presented for the first time. No effective regulations on NOx emissions have been implemented for ships in China, which is reflected in the trend analysis of maritime emissions. The maritime emissions display a continuous increase rate of about 20% per year until 2012 and slow down to 3% after that. The seasonal cycle of shipping emissions has regional variations, but all regions show lower emissions during winter. Simulations by an atmospheric chemistry transport model show a notable influence of maritime emissions on air pollution over coastal areas, especially in summer. The satellite-derived spatial distribution and the magnitude of maritime emissions over Chinese seas are in good agreement with bottom-up studies based on the Automatic Identification System of ships.

  2. Pilot test and optimization of plasma based deNOx

    DEFF Research Database (Denmark)

    Stamate, Eugen; Chen, Weifeng; Michelsen, Poul

    . Experiments are in good agreement with numerical simulations. An optimized oxidation scheme for NOx reduction processes with time dependent combustion, such as the biomass power plants, was developed. Ozone production by micro-hollow and capillary discharges at atmospheric pressures was investigated......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...

  3. 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.

  4. Effect of gas recirculation in a pilot-scale cow-dung digester

    Energy Technology Data Exchange (ETDEWEB)

    Pathak, B N; Kulkarni, D N; Dave, J M; Mohanrao, G J

    1965-01-01

    Laboratory experiments showed that if, during anaerobic digestion of cow manure, the contents of the digestion vessel are mixed by recirculating gas, nearly twice as much gas is produced, and there is less variation in the temperature of the digesting liquor, the pH value, the carbon-dioxide content of the gas, and the reduction in volatile matter. Results of experiments during which gas was recirculated for periods ranging from 0 to 4 hours are tabulated.

  5. KE basin recirculation/skimmer/IX systems restart acceptance test report

    International Nuclear Information System (INIS)

    Derosa, D.C.

    1996-01-01

    The 105 KE Basin Recirculation System and Skimmer Loop have been upgraded to provide the flexibility to run the Ion Exchange Modules on either system to support spent fuel removal for the Spent Nuclear Fuel Project. This Acceptance Test Report Provides the documentation of the leak Testing for the construction work associated with the IXM inlet and outlet piping, places the cartridge filters back in service and provides the functional testing of the IXM's on the recirculation and skimmer systems

  6. Impaired compensation to femoral artery ligation in diet-induced obese mice is primarily mediated via suppression of collateral growth by Nox2 and p47phox.

    Science.gov (United States)

    DiStasi, Matthew R; Mund, Julie A; Bohlen, H Glenn; Miller, Steven J; Ingram, David A; Dalsing, Michael C; Unthank, Joseph L

    2015-10-01

    The present study was undertaken to establish the role of NADPH oxidase (Nox) in impaired vascular compensation to arterial occlusion that occurs in the presence of risk factors associated with oxidative stress. Diet-induced obese (DIO) mice characterized by multiple comorbidities including diabetes and hyperlipidemia were used as a preclinical model. Arterial occlusion was induced by distal femoral artery ligation in lean and DIO mice. Proximal collateral arteries were identified as the site of major (∼70%) vascular resistance to calf perfusion by distal arterial pressures, which decreased from ∼80 to ∼30 mmHg with ligation in both lean and DIO mice. Two weeks after ligation, significant vascular compensation occurred in lean but not DIO mice as evidenced by increased perfusion (147 ± 48% vs. 49 ± 29%) and collateral diameter (151 ± 30% vs. 44 ± 17%). Vascular mRNA expression of p22(phox), Nox2, Nox4, and p47(phox) were all increased in DIO mice. Treatment of DIO mice with either apocynin or Nox2ds-tat or with whole body ablation of either Nox2 or p47(phox) ameliorated the impairment in both collateral growth and hindlimb perfusion. Multiparametric flow cytometry analysis demonstrated elevated levels of circulating monocytes in DIO mice without impaired mobilization and demargination after femoral artery ligation. These results establish collateral resistance as the major limitation to calf perfusion in this preclinical model, demonstrate than monocyte mobilization and demarginatin is not suppressed, implicate Nox2-p47(phox) interactions in the impairment of vascular compensation to arterial occlusion in DIO mice, and suggest that selective Nox component suppression/inhibition may be effective as either primary or adjuvant therapy for claudicants. Copyright © 2015 the American Physiological Society.

  7. 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.

  8. Recirculation of Chilean copper smelting dust with high impurities contents to the smelting process

    Energy Technology Data Exchange (ETDEWEB)

    Sano, H.; Fujisawa, T. [Nagoya Univ., Nagoya (Japan). EcoTopia Science Inst.; Montenegro, V. [Nagoya Univ., Nagoya (Japan). Dept. of Materials Science and Engineering

    2007-07-01

    Dust generated during the copper smelting process is generally stabilized using hydrometallurgical methods as it contains high concentrations of arsenic. In this laboratory study, dust was recirculated during the smelting process in order to recover more copper and decrease dust emissions while recovering more copper. The behaviour of impurities and their influence on matte quality was also investigated. Industrial matte, flue dust, slag, and copper concentrates from a Chilean smelter were used as test materials. Dust recirculation tests were conducted in a simulated electric furnace. Off-gases were collected in a reaction tube, and the condensed volatile matter, slag, and matte phases were analyzed for their elemental content by inductively coupled plasma atomic emission spectrometry. The distribution of arsenic (As); antimony (Sb), bismuth (Bi), lead (Pb), and zinc (Zn) were investigated by varying the amounts of dust recirculating to the smelting stage with 21 per cent of the oxygen. Results showed that distributions of all analyzed elements increased with recirculation. It was concluded that copper can be recovered using the dust recirculation technique. However, impurities may limit the efficacy of the dust recirculation process. 6 refs., 3 tabs., 4 figs.

  9. Theoretical analysis of recirculation zone and buffer zone in the ADS windowless spallation target

    International Nuclear Information System (INIS)

    Liu, Jie; Pan, Chang-zhao; Tong, Jian-fei; Lu, Wen-qiang

    2015-01-01

    Highlights: • Height of recirculation zone is very important in windowless target design. • A theoretical formula for the height is derived based on the Bernoulli equation. • Numerical simulation for the LBE is performed and the height of recirculation zone is also obtained. • The theoretically-derived simulation-predicted recirculation zone heights agree with each other very well and the theoretical derivation is proved to be correct. - Abstract: The thermo-hydraulic analysis including reduction of the height of recirculation zone and stability of the free surface is very important in the design and optimization of ADS windowless spallation targets. In the present study, the Bernoulli equation is used to analyze the entire flow process in the target. Formulae for the height of the recirculation zone and the buffer zone are both obtained explicitly. Furthermore, numerical simulation for the heavy metal lead–bismuth eutectic liquid and vapor with cavitation phase change is also performed, and a novel method to calculate the height of the recirculation zone is put forward. By comparison of the theoretical formulae and numerical results, it is clearly shown that they agree with each other very well, and the heights predicted by the two methods are both determined by their own upstream flow parameters

  10. 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.

  11. Post combustion methods for control of NOx emission

    Energy Technology Data Exchange (ETDEWEB)

    Rosenberg, H S; Curran, L M; Slack, A V; Ando, J; Oxley, J H

    1980-01-01

    Review of stack gas treatment methods for the control of NOx emissions. Particular emphasis is placed on status of development and factors affecting the performance of the processes. Catalytic, noncatalytic, and scrubbing processes are compared on a uniform engineering basis. Most of the active process development work is taking place in Japan. The three leading stack gas treatment techniques for NOx control are catalytic reduction with ammonia, noncatalytic reduction with ammonia, and direct scrubbing of NO with simultaneous absorption of SO2. The wet processes are much less developed than the dry processes.

  12. Data quality objectives summary report for the 107-N Basin Recirculation Building liquid/sediment

    International Nuclear Information System (INIS)

    Pisarcik, D.J.

    1998-01-01

    The Data Quality Objectives (DQO) process used for this 107-N Basin Recirculation Building liquid/sediment DQO report followed BHI-EE-01, Environmental Investigations Procedures, EIIP 1.2, Data Quality Objectives, Revision 2. Tri-Party Agreement Milestone (M-16-OIE) states that the 100-N Area deactivation must be performed according to the work scope identified in the N Reactor Deactivation Program Plan (WHC 1993c). Consistent with the N Reactor Deactivation Program Plan, the scope of the 107-N liquid/sediment DQO process exclusively involves the determination of sampling requirements during the deactivation period. The sampling requirements are primarily directed at characterization for comparison to decontamination and decommissioning endpoint acceptance criteria in preparation for turnover of the facilities listed below to the D and D organization. The sample characterization will also be used for selection of the appropriate disposition option for liquid and sediment currently contained in the facility. The primary media within the scope of this DQO includes the following: Accumulated liquids and sediment contained in tanks, vessels, pump wells, sumps, associated piping, and valve pit floors; and Limited solid debris (anticipated to be discovered)

  13. Effect of automatic recirculation flow control on the transient response for Lungmen ABWR plant

    Energy Technology Data Exchange (ETDEWEB)

    Tzang, Y.-C., E-mail: yctzang@aec.gov.t [National Tsing Hua University, Department of Engineering and System Science, Hsinchu 30013, Taiwan (China); Chiang, R.-F.; Ferng, Y.-M.; Pei, B.-S. [National Tsing Hua University, Department of Engineering and System Science, Hsinchu 30013, Taiwan (China)

    2009-12-15

    In this study the automatic mode of the recirculation flow control system (RFCS) for the Lungmen ABWR plant has been modeled and incorporated into the basic RETRAN-02 system model. The integrated system model is then used to perform the analyses for the two transients in which the automatic RFCS is involved. The two transients selected are: (1) one reactor internal pump (RIP) trip, and (2) loss of feedwater heating. In general, the integrated system model can predict well the response of key system parameters, including neutron flux, steam dome pressure, heat flux, RIP flow, core inlet flow, feedwater flow, steam flow, and reactor water level. The transients are also analyzed for manual RFCS case, between the automatic RFCS and the manual RFCS cases, comparisons of the transient response for the key system parameter show that the difference of transient response can be clearly identified. Also, the results show that the DELTACPR (delta critical power ratio) for the transients analyzed may not be less limiting for the automatic RFCS case under certain combination of control system settings.

  14. Sampling and analysis plan for the 107-N Basin recirculation building liquid/sediment

    International Nuclear Information System (INIS)

    Thompson, W.S.

    1997-02-01

    This sampling and analysis plan (SAP) defines the strategy and the field and laboratory methods that will be used to characterize the liquids and sediment within the following four 100-N buildings/areas: 1310-N valve pit area inside the Radioactive Chemical Waste Treatment Pump House (silo); 1314-N Waste Pump (Overflow) Tank at the Liquid Waste Disposal Station; 105-N Lift Station pump well and valve pit areas inside the 105-N Reactor Building; and 107-N Basin Recirculation Building. This characterization activity is being performed in support of the work scope identified in the N Reactor Deactivation Program Plan and the sampling strategy in the DQO. The characterization data will be used for comparison to decontamination and decommissioning (D and D) endpoint acceptance criteria in preparation for turnover of the above-listed facilities to the D and D project. The data will also be used for waste acceptance criteria evaluation in the selection of the appropriate disposition option for liquid and sediment currently contained in the facilities

  15. 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

  16. 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

  17. Two-stage Catalytic Reduction of NOx with Hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

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

    2005-12-21

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

  18. 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...

  19. NOx reduction and NO2 emission characteristics in rich-lean combustion of hydrogen

    OpenAIRE

    Shudo, Toshio; Omori, Kento; Hiyama, Osamu

    2008-01-01

    Hydrogen is a clean alternative to conventional hydrocarbon fuels, but it is very important to reduce the nitrogen oxides (NOx) emissions generated by hydrogen combustion. The rich-lean combustion or staged combustion is known to reduce NOx emissions from continuous combustion burners such as gas turbines and boilers, and NOx reduction effects have been demonstrated for hydrocarbon fuels. The authors applied rich-lean combustion to a hydrogen gas turbine and showed its NOx reduction effect in...

  20. 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 H...

  1. Evaluation on Biofilter in Recirculating Integrated Multi-Trophic Aquaculture

    Directory of Open Access Journals (Sweden)

    S. Sumoharjo

    2013-06-01

    Full Text Available Integrated multi-trophic aquaculture pays more attention as a bio-integrated food production system that serves as a model of sustainable aquaculture, minimizes waste discharge, increases diversity and yields multiple products. The objectives of this research were to analyze the efficiency of total ammonia nitrogen biofiltration and its effect on carrying capacity of fish rearing units. Pilot-scale bioreactor was designed with eight run-raceways (two meters of each that assembled in series. Race 1-3 were used to stock silky worm (Tubifex sp as detrivorous converter, then race 4-8 were used to plant three species of leaf-vegetable as photoautotrophic converters, i.e; spinach (Ipomoea reptana, green mustard (Brassica juncea and basil (Ocimum basilicum. The three plants were placed in randomized block design based on water flow direction. Mass balance of nutrient analysis, was applied to figure out the efficiency of bio-filtration and its effect on carrying capacity of rearing units. The result of the experiment showed that 86.5 % of total ammonia nitrogen removal was achieved in 32 days of culturing period. This efficiency able to support the carrying capacity of the fish tank up to 25.95 kg/lpm with maximum density was 62.69 kg/m3 of fish biomass productionDoi: http://dx.doi.org/10.12777/ijse.4.2.2013.80-85 [How to cite this article: Sumoharjo, S.  and Maidie, A. (2013. Evaluation on Biofilter in Recirculating Integrated Multi-Trophic Aquaculture.  International Journal of  Science and Engineering, 4(2,80-85. Doi: http://dx.doi.org/10.12777/ijse.4.2.2013.80-85

  2. Beam transport physics issues for the recirculating linear accelerator

    International Nuclear Information System (INIS)

    Shokair, I.R.

    1992-11-01

    The Recirculating Linear Accelerator (RLA) utilizes the Ion Focused Regime (IFR) of beam transport plus a ramped bending field to guide the beam around the curved sections. Several issues of beam transport are considered. Beam transverse perturbations that could result in growth of the ion hose instability are analyzed. It is found that transverse kicks due to bending field errors, energy mismatches and fringe fields are the most important. The scaling of these perturbations with beam and channel parameters is derived. The effect of ramping of the bending field on the preformed plasma channel is then considered. For RLA experimental parameters the effect is found to be very small. For high energies however, in addition to axial heating, it is found that ramping the field causes compression of the plasma channel along the radius of curvature. This compression results in a quasi-equilibrium plasma electron temperature along the field lines which leads to collisionless transport towards the walls. The analysis of compression is done in an approximate way using a single particle picture and the channel expansion is analyzed using an envelope solution which gives a simple expression for the expansion time. This solution is then verified by Buckshot simulations. For a bending field of 2 kG ramped in 2 μ-secs and an argon channel (RLA parameters) we estimate that the channel radius doubling time (along field lines) is of the order of 0.5 μ-secs. Finally the effect of electron impact ionization due to axially heated electrons by the action of the inductive field is estimated. It is found that in Argon gas the electron avalanche time could be as low as 0.5 μ-sec which is smaller than the field ramp time

  3. Debris impact on emergency coolant recirculation - summary and conclusions

    International Nuclear Information System (INIS)

    Jain, Bhagwat; Hsia, Anthony; Armand, Yves; Mattei, Jean-Marie; Hyvaerinen, Juhani; Maqua, Michael; Puetter, Bernhard; Sandervaag, Oddbjoern; Vandewalle, Andre; Tombuyses, Beatrice; Pyy, Pekka; Royen, Jacques

    2004-01-01

    On 28 July 1992, a steam line safety relief valve inadvertently opened in the Barsebaeck-2 nuclear power plant in Sweden. The steam jet stripped fibrous insulation from adjacent piping system. Part of that insulation debris was transported to the wet-well pool and clogged the intake strainers for the drywell spray system after about one hour. Although the incident in itself was not very serious, it revealed a weakness in the defense-in-depth concept which under other circumstances could have led to the emergency core cooling system (ECCS) failing to provide recirculation water to the core. The Barsebaeck incident spurred immediate action on the part of regulators and utilities alike in several OECD countries. Research and development efforts of varying degrees of intensity were launched in many countries and in several cases resulted in findings that earlier strainer clogging data were incorrect because essential parameters and physical phenomena had not been recognized previously. Such efforts resulted in substantial back-fittings being carried out for BWRs and some PWRs in several OECD countries. An international workshop organised in Stockholm in 1994 under the auspices of CSNI revealed a rather confusing picture of the available knowledge base, examples of conflicting information and a wide range of interpretation of guidance for assessing BWR strainers and PWR sump screen performance contained in US NRC Regulatory Guide 1.82. An International Working Group was set up by the CSNI to establish an internationally agreed-upon knowledge base for assessing the reliability of ECC water recirculation systems. An initiative was taken by the CSNI in 1998 to revisit the subject. The general objective was to make an update of the knowledge base for strainer clogging, to review the latest phenomena for PWRs and to provide a survey of actions taken in member countries. New information contained in NUREG/CR-6771 indicated that the core damage frequency could increase by one

  4. 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.

  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 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...

  7. 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:…

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

    Science.gov (United States)

    2010-07-01

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

  9. Low-level NOx removal in ambient air by pulsed corona technology

    NARCIS (Netherlands)

    Beckers, F.J.C.M.; Hoeben, W.F.L.M.; Pemen, A.J.M.; Heesch, van E.J.M.

    2013-01-01

    Although removal of NOx by (pulsed) corona discharges has been thoroughly investigated for high concentrations of NOx in flue gas, removal of low levels in ambient air proves to be a difficult task. (Sub) ppm NOx levels exist in traffic tunnels due to accumulation of exhaust gases. The application

  10. 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...

  11. 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

  12. The Reduction of NOx Using Pulsed Electron Beams

    Science.gov (United States)

    2015-12-30

    instantly with oxygen to form the brown gas NO2. Nitrogen dioxide is toxic . Dinitrogen trioxide (N2O3) exists as a deep blue solid (-21°C), but is... Fluoride Laser System,” Optical Engineering 47, 104202 (2008). [6] M.F. Wolford, M.C. Myers, F. Hegeler, J.D. Sethian, “NOx Removal with Multiple

  13. 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...

  14. Estimates of lightning NOx production from GOME satellite observations

    NARCIS (Netherlands)

    Boersma, K.F.; Eskes, H.J.; Meijer, E.W.; Kelder, H.M.

    2005-01-01

    Tropospheric NO2 column retreivals from the Global Ozone Monitoring Expeiment (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

  15. Effect of blending different rank coals on NOx emissions

    Energy Technology Data Exchange (ETDEWEB)

    Rubiera, F.; Esteban, R.; Arenillas, A.; Pis, J.J. [Instituto Nacional del Carbon, Oviedo (Spain)

    1999-07-01

    A study was carried out to assess the NOx emissions when the fraction of high-volatile coals in blends with low-volatile coals, such as anthracitic and semianthracitic, was increased. Burnout and NO emissions were determined for individual coals and their blends. 4 refs., 4 figs., 1 tab.

  16. 40 CFR 97.142 - CAIR NOX allowance allocations.

    Science.gov (United States)

    2010-07-01

    ... heat input for each year calculated as follows: (A) If the unit is coal-fired during the year, the unit... the first such 5 years. (2)(i) A unit's control period heat input, and a unit's status as coal-fired... Allocations § 97.142 CAIR NOX allowance allocations. (a)(1) The baseline heat input (in mmBtu) used with...

  17. NOx and SO2 emission factors for Serbian lignite Kolubara

    Directory of Open Access Journals (Sweden)

    Jovanović Vladimir V.

    2012-01-01

    Full Text Available Emission factors are widely accepted tool for estimation of various pollutants emissions in USA and EU. Validity of emission factors is strongly related to experimental data on which they are based. This paper is a result of an effort to establish reliable NOx and SO2 emission factors for Serbian coals. The results of NOx and SO2 emissions estimations based on USA and EU emission factors from thermal power plants Nikola Tesla Obrenovac A and B utilizing the Serbian lignite Kolubara are compared with experimental data obtained during almost one decade (2000-2008 of emissions measurements. Experimental data are provided from regular annual emissions measurement along with operational parameters of the boiler and coal (lignite Kolubara ultimate and proximate analysis. Significant deviations of estimated from experimental data were observed for NOx, while the results for SO2 were satisfactory. Afterwards, the estimated and experimental data were plotted and linear regression between them established. Single parameter optimization was performed targeting the ideal slope of the regression line. Results of this optimization provided original NOx and SO2 emission factors for Kolubara lignite.

  18. 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.

  19. 40 CFR 89.317 - NOX converter check.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false NOX converter check. 89.317 Section 89.317 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED..., the chemiluminescent oxides of nitrogen analyzer shall be checked for NO2 to NO converter efficiency...

  20. 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.

  1. NOx from lightning: 1. Global distribution based on lightning physics

    Science.gov (United States)

    Price, Colin; Penner, Joyce; Prather, Michael

    1997-03-01

    This paper begins a study on the role of lightning in maintaining the global distribution of nitrogen oxides (NOx) in the troposphere. It presents the first global and seasonal distributions of lightning-produced NOx (LNOx) based on the observed distribution of electrical storms and the physical properties of lightning strokes. We derive a global rate for cloud-to-ground (CG) flashes of 20-30 flashes/s with a mean energy per flash of 6.7×109 J. Intracloud (IC) flashes are more frequent, 50-70 flashes/s but have 10% of the energy of CG strokes and, consequently, produce significantly less NOx. It appears to us that the majority of previous studies have mistakenly assumed that all lightning flashes produce the same amount of NOx, thus overestimating the NOx production by a factor of 3. On the other hand, we feel these same studies have underestimated the energy released in CG flashes, resulting in two negating assumptions. For CG energies we adopt a production rate of 10×1016 molecules NO/J based on the current literature. Using a method to simulate global lightning frequencies from satellite-observed cloud data, we have calculated the LNOx on various spatial (regional, zonal, meridional, and global) and temporal scales (daily, monthly, seasonal, and interannual). Regionally, the production of LNOx is concentrated over tropical continental regions, predominantly in the summer hemisphere. The annual mean production rate is calculated to be 12.2 Tg N/yr, and we believe it extremely unlikely that this number is less than 5 or more than 20 Tg N/yr. Although most of LNOx, is produced in the lowest 5 km by CG lightning, convective mixing in the thunderstorms is likely to deposit large amounts of NOx, in the upper troposphere where it is important in ozone production. On an annual basis, 64% of the LNOx, is produced in the northern hemisphere, implying that the northern hemisphere should have natural ozone levels as much as 2 times greater than the southern hemisphere

  2. Mineral and organic compounds in leachate from landfill with concentrate recirculation.

    Science.gov (United States)

    Talalaj, Izabela Anna

    2015-02-01

    The effect of a reverse osmosis concentrate recirculation on the mineral and organic compounds in a landfill leachate was investigated. Investigated was the quality of a leachate from two landfills operated for different periods (a 20-year-old Cell A and a 1-year-old Cell B), where the concentrate was recirculated. Examined were general parameters (conductivity, pH), organic compounds (biochemical oxygen demand (BOD), chemical oxygen demand (COD), total organic nitrogen, BOD/COD), and inorganic compounds (nitrogen ammonia, sulfite, sulfate, cyanide, boron, chloride, ferrous, zinc, chrome, copper). The findings from the first year of investigation showed that over the initial period of recirculation, the concentration of organic compounds (BOD, COD) increased, but after 6 months their values stabilized. It indicates that the concentrate recirculation accelerated organic decomposition, especially in the new landfill Cell. The analysis of inorganic parameters showed that recirculation landfills produce a leachate with a higher concentration of N-NH4, and Cl(-). In case of the old landfill Cell, an increase in B and Fe was also noticeable. These compounds are cyclically washed out from a waste dump and require an additional pretreatment in order to exclude them from recirculation cycle. The increased concentration of Cu, Zn, and Fe was noticed during the initial months of recirculation and in the season of intense atmospheric precipitation in the leachate from both Cells. Higher values of electro conductivity, Cl(-), N-NH4 (+), B, and Fe in the leachate from the old field indicate that the attenuation capacity of this landfill is close to exhaustion.

  3. Effect of adding a swirl on flow pattern and recirculation zone in ADS windowless spallation target

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Jie, E-mail: nauty@ucas.ac.cn [School of Physics, University of Chinese Academy of Sciences, Beijing (China); Gao, Lei [School of Physics, University of Chinese Academy of Sciences, Beijing (China); Yang, Lei [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou (China); Lu, Wen-qiang [School of Physics, University of Chinese Academy of Sciences, Beijing (China)

    2014-09-15

    Highlights: • The reduction of the recirculation zone and the stability of the free surface are key issues in the target. • A swirl is numerically added in the target to make the recirculation zone small and stable. • Numerical simulation with different boundary conditions is carried out. • Physical analysis is presented to explain the numerical results. - Abstract: Aiming the key issues in the accelerator driven system (ADS), windowless spallation target focus on the minimization of the recirculation zone and on the stability of the free surface, an innovation has been made by numerically adding swirl to the fluid at the inlet. At first, two phase flow pattern in the simulation is compared with the experiments and numerical method is employed correctly. The results reveal that the recirculation zone and the flow pattern are greatly influenced when the swirl strength is changed from 1.0 rad/s to 2.5 rad/s. The height of the recirculation zone decreases with increase in swirl strength and completely disappears when the swirl strength reaches 2.0 rad/s. In addition, larger swirl strength leads to different flow pattern and a new cavitation zone is generated under the recirculation zone. The Bernoulli's equation and angular momentum conservation are applied to make it clear that this phenomena is due to the decrease of the axial pressure caused by the radial velocity. Moreover, the new cavitation zone totally links to the vapor area above the recirculation zone when the swirl strength is 2.5 rad/s. The results are very helpful to the design and optimization of the ADS windowless spallation target.

  4. Effect of adding a swirl on flow pattern and recirculation zone in ADS windowless spallation target

    International Nuclear Information System (INIS)

    Liu, Jie; Gao, Lei; Yang, Lei; Lu, Wen-qiang

    2014-01-01

    Highlights: • The reduction of the recirculation zone and the stability of the free surface are key issues in the target. • A swirl is numerically added in the target to make the recirculation zone small and stable. • Numerical simulation with different boundary conditions is carried out. • Physical analysis is presented to explain the numerical results. - Abstract: Aiming the key issues in the accelerator driven system (ADS), windowless spallation target focus on the minimization of the recirculation zone and on the stability of the free surface, an innovation has been made by numerically adding swirl to the fluid at the inlet. At first, two phase flow pattern in the simulation is compared with the experiments and numerical method is employed correctly. The results reveal that the recirculation zone and the flow pattern are greatly influenced when the swirl strength is changed from 1.0 rad/s to 2.5 rad/s. The height of the recirculation zone decreases with increase in swirl strength and completely disappears when the swirl strength reaches 2.0 rad/s. In addition, larger swirl strength leads to different flow pattern and a new cavitation zone is generated under the recirculation zone. The Bernoulli's equation and angular momentum conservation are applied to make it clear that this phenomena is due to the decrease of the axial pressure caused by the radial velocity. Moreover, the new cavitation zone totally links to the vapor area above the recirculation zone when the swirl strength is 2.5 rad/s. The results are very helpful to the design and optimization of the ADS windowless spallation target

  5. High-Speed Multiplexed Spatiotemporally Resolved Measurements of Exhaust Gas Recirculation Dynamics in a Multi-Cylinder Engine Using Laser Absorption Spectroscopy.

    Science.gov (United States)

    Yoo, Jihyung; Prikhodko, Vitaly; Parks, James E; Perfetto, Anthony; Geckler, Sam; Partridge, William P

    2016-04-01

    The need for more environmentally friendly and efficient energy conversion is of paramount importance in developing and designing next-generation internal combustion (IC) engines for transportation applications. One effective solution to reducing emissions of mono-nitrogen oxides (NOx) is exhaust gas recirculation (EGR), which has been widely implemented in modern vehicles. However, cylinder-to-cylinder and cycle-to-cycle variations in the charge-gas uniformity can be a major barrier to optimum EGR implementation on multi-cylinder engines, and can limit performance, stability, and efficiency. Precise knowledge and fine control over the EGR system is therefore crucial, particularly for optimizing advanced engine concepts such as reactivity controlled compression ignition (RCCI). An absorption-based laser diagnostic was developed to study spatiotemporal charge-gas distributions in an IC engine intake manifold in real-time. The laser was tuned to an absorption band of carbon dioxide (CO2), a standard exhaust-gas marker, near 2.7 µm. The sensor was capable of probing four separate measurement locations simultaneously, and independently analyzing EGR fraction at speeds of 5 kHz (1.2 crank-angle degree (CAD) at 1 k RPM) or faster with high accuracy. The probes were used to study spatiotemporal EGR non-uniformities in the intake manifold and ultimately promote the development of more efficient and higher performance engines. © The Author(s) 2016.

  6. Preparation of highly active manganese oxides supported on functionalized MWNTs for low temperature NOx reduction with NH3

    Science.gov (United States)

    Pourkhalil, Mahnaz; Moghaddam, Abdolsamad Zarringhalam; Rashidi, Alimorad; Towfighi, Jafar; Mortazavi, Yadollah

    2013-08-01

    Manganese oxide catalysts (MnOx) supported on functionalized multi-walled carbon nanotubes (FMWNTs) for low temperature selective catalytic reduction (LTSCR) of nitrogen oxides (NOx) with NH3 in the presence of excess O2 were prepared by the incipient wetness impregnation method. These catalysts were characterized by N2 adsorption, Fourier transform infrared spectroscopy (FTIR), transmission electron microscope (TEM), X-ray diffraction (XRD), thermal gravimetric analysis (TGA) and H2-temperature programmed reduction (H2-TPR) methods. The effects of reaction temperature, MnOx loading, calcination temperature and calcination time were investigated. The presence of surface nitrate species under moderate calcination conditions may play a favorable role in the LTSCR of NOx with NH3. Under the reaction conditions of 200 °C, 1 bar, NO = NH3 = 900 ppm, O2 = 5 vol%, GHSV = 30,000 h-1 and 12 wt% MnOx, NOx conversion and N2 selectivity were 97% and 99.5%, respectively. The SCR activity was reduced in the presence of 100 ppm SO2 and 2.5 vol% H2O from 97% to 92% within 6 h at 200 °C, however such an effect was shown to be reversible by exposing the catalyst to a helium flow for 2 h at 350 °C due to thermal decomposition of ammonium sulphate salts.

  7. NOx, Soot, and Fuel Consumption Predictions under Transient Operating Cycle for Common Rail High Power Density Diesel Engines

    Directory of Open Access Journals (Sweden)

    N. H. Walke

    2016-01-01

    Full Text Available Diesel engine is presently facing the challenge of controlling NOx and soot emissions on transient cycles, to meet stricter emission norms and to control emissions during field operations. Development of a simulation tool for NOx and soot emissions prediction on transient operating cycles has become the most important objective, which can significantly reduce the experimentation time and cost required for tuning these emissions. Hence, in this work, a 0D comprehensive predictive model has been formulated with selection and coupling of appropriate combustion and emissions models to engine cycle models. Selected combustion and emissions models are further modified to improve their prediction accuracy in the full operating zone. Responses of the combustion and emissions models have been validated for load and “start of injection” changes. Model predicted transient fuel consumption, air handling system parameters, and NOx and soot emissions are in good agreement with measured data on a turbocharged high power density common rail engine for the “nonroad transient cycle” (NRTC. It can be concluded that 0D models can be used for prediction of transient emissions on modern engines. How the formulated approach can also be extended to transient emissions prediction for other applications and fuels is also discussed.

  8. 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

  9. Functions and regulation of the Nox family in the filamentous fungus Podospora anserina: a new role in cellulose degradation.

    Science.gov (United States)

    Brun, Sylvain; Malagnac, Fabienne; Bidard, Frédérique; Lalucque, Hervé; Silar, Philippe

    2009-10-01

    NADPH oxidases are enzymes that produce reactive oxygen species. Studies in mammals, plants and fungi have shown that they play important roles in differentiation, defence, host/pathogen interaction and mutualistic symbiosis. In this paper, we have identified a Podospora anserina mutant strain impaired for processes controlled by PaNox1 and PaNox2, the two Nox isoforms characterized in this model ascomycete. We show that the gene mutated is PaNoxR, the homologue of the gene encoding the regulatory subunit p67(phox), conserved in mammals and fungi, and that PaNoxR regulates both PaNox1 and PaNox2. Genome sequence analysis of P. anserina reveals that this fungus posses a third Nox isoform, PaNox3, related to human Nox5/Duox and plant Rboh. We have generated a knock-out mutant of PaNox3 and report that PaNox3 plays a minor role in P. anserina, if any. We show that PaNox1 and PaNox2 play antagonist roles in cellulose degradation. Finally, we report for the first time that a saprobic fungus, P. anserina, develops special cell structures dedicated to breach and to exploit a solid cellulosic substrate, cellophane. Importantly, as for similar structures present in some plant pathogens, their proper differentiation requires PaNox1, PaNox2, PaNoxR and the tetraspanin PaPls1.

  10. Experimental investigation on the influences of exhaust gas recirculation coupling with intake tumble on gasoline engine economy and emission performance

    International Nuclear Information System (INIS)

    Fu, Jianqin; Zhu, Guohui; Zhou, Feng; Liu, Jingping; Xia, Yan; Wang, Shuqian

    2016-01-01

    Highlights: • In-cylinder residual gas fraction almost increases linearly with exhaust gas recirculation rate. • Heat transfer loss and exhaust gas energy loss decrease with exhaust gas recirculation rate. • Engine indicated thermal efficiency can be increased by 4.29% at 1600 r/min and 2.94 bar. • The effective range of exhaust gas recirculation rate can be extended by intake tumble. - Abstract: To improve the economy and emission performance of gasoline engine under part load, the approach of exhaust gas recirculation coupling with intake tumble was investigated by bench testing. Based on a naturally aspirated gasoline engine, the sweeping test of exhaust gas recirculation rate was conducted in two intake modes (with/without intake tumble), and the parameters related to engine heat-work conversion process and emission performance were measured. Through comparing and analyzing the measured data, the effects of exhaust gas recirculation coupling with intake tumble on gasoline engine economy and emission performance were revealed. The results show that pumping loss decreases gradually while in-cylinder residual gas fraction increases linearly with the exhaust gas recirculation rate increasing; the high-pressure cycle efficiency ascends with exhaust gas recirculation rate increasing due to the decrease of heat transfer loss and exhaust gas energy loss. Thus, the improvement of indicated thermal efficiency is the superposition of double benefits of low-pressure cycle and high-pressure cycle. At 1600 r/min and 2.94 bar, the indicated thermal efficiency can be increased by 4.29%. With the increase of exhaust gas recirculation rate, nitrogen oxide emissions almost fall linearly, but hydrocarbon and carbonic oxide emissions have no obvious change in the effective range of exhaust gas recirculation rate. The biggest advantage of intake tumble is that it can extend the effective range of exhaust gas recirculation rate. As a result, the potential of energy

  11. Hot test of a TALSPEAK procedure for separation of actinides and lanthanides using recirculating DTPA-lactic acid solution

    International Nuclear Information System (INIS)

    Persson, G.; Svantesson, I.; Wingefors, S.; Liljenzin, J.O.

    1984-01-01

    Results are reported from a hot test of a TALSPEAK type process for separation of higher actinides (Am, Cm) from lanthanides. Actinides and lanthanides are extracted by 1 M HDEHP and separated by selective strip of the actinides, using a mixture of DTPA and lactic acid (reversed TALSPEAK process). In order to minimize the generation of secondary waste, a procedure using recirculating DTPA-Lactic acid solution has been developed. A separation factor between Am and Eu of 132 was achieved. In regard to separations of Am and Cm from commercial HLLW (high level liquid wastes), the factor corresponds to 1.5% of the lanthanide group remaining with the actinides. The loss of Am was about 0.2%. 9 figures, 3 tables

  12. Constitutive NADPH-Dependent Electron Transferase Activity of the Nox4 Dehydrogenase Domain?

    OpenAIRE

    Nisimoto, Yukio; Jackson, Heather M.; Ogawa, Hisamitsu; Kawahara, Tsukasa; Lambeth, J. David

    2010-01-01

    NADPH oxidase 4 (Nox4) is constitutively active, while Nox2 requires the cytosolic regulatory subunits p47 phox and p67 phox and activated Rac with activation by phorbol 12-myristate 13-acetate (PMA). This study was undertaken to identify the domain on Nox4 that confers constitutive activity. Lysates from Nox4-expressing cells exhibited constitutive NADPH- but not NADH-dependent hydrogen peroxide production with a K m for NADPH of 55 ? 10 ?M. The concentration of Nox4 in cell lysates was esti...

  13. 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

  14. 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

  15. Effect of a sustainable biofuel – n-octanol – on the combustion, performance and emissions of a DI diesel engine under naturally aspirated and exhaust gas recirculation (EGR) modes

    International Nuclear Information System (INIS)

    Rajesh Kumar, B.; Saravanan, S.; Rana, D.; Anish, V.; Nagendran, A.

    2016-01-01

    Highlights: • It is possible to operate a DI diesel engine with up to 30% n-octanol/diesel blends without modifications. • Addition of n-octanol prolonged the ignition delay, generated higher peaks of pressure and heat release rates. • Simultaneous reduction of NOx and smoke is possible under both naturally-aspirated and EGR conditions. • Engine performance improved with n-octanol addition. • HC and CO emissions decreased favorably with n-octanol addition. - Abstract: Higher alcohols above n-butanol can be excellent alternative fuels for diesel engines owing to their high energy content and high cetane number. The last three years has witnessed an advent of several sustainable pathways for n-octanol bio-synthesis using engineered-microbes like Escherichia coli and Clostridium species. Therefore an investigation to evaluate the compatibility of n-octanol in diesel engines becomes essential. The influence of blending n-octanol by up to 30 vol% with fossil diesel on combustion, performance and emission characteristics of a single cylinder direct-injection (DI) diesel engine under both naturally aspirated and exhaust gas recirculation (EGR) modes was investigated with reference to diesel. Results showed that n-octanol prolonged the ignition delay generating higher peaks of in-cylinder pressure and heat release rates (HRR) during the pre-mixed combustion phase. Brake thermal efficiency (BTE) increased while brake specific fuel consumption (BSFC) decreased with an increase in n-octanol fraction. Smoke, NOx (nitrogen oxides), HC (hydro-carbons) and CO (carbon monoxide) emissions decreased with n-octanol addition. NOx and smoke emissions also remained low at all EGR rates. Both BTE and BSFC suffered at increased EGR rates. HC and CO emissions increased with escalating EGR rates. n-Octanol was found to be very promising for replacing fossil-diesel by up to 30% (subject to long term durability tests), in terms of emissions and performance at both naturally

  16. Validation of enhanced stabilization of municipal solid waste under controlled leachate recirculation using FTIR and XRD.

    Science.gov (United States)

    Sethi, Sapna; Kothiyal, N C; Nema, Arvind K

    2012-07-01

    Leachate recirculation at neutral PH accompanied with buffer/nutrients addition has been used successfully in earlier stabilization of municipal solid waste in bioreactor landfills. In the present study, efforts were made to enhance the stabilization rate of municipal solid waste (MSW) and organic solid waste (OSW) in simulated landfill bioreactors by controlling the pH of recirculated leachate towards slightly alkaline side in absence of additional buffer and nutrients addition. Enhanced stabilization in waste samples was monitored with the help of analytical tools like Fourier Transform Infrared Spectroscopy (FTIR) and X-Ray Diffraction (XRD). Predominance of bands assigned to inorganic compounds and comparatively lower intensities of bands for organic compounds in the FTIR spectra of waste samples degraded with leachate recirculation under controlled pH confirmed higher rate of biodegradation and mineralization of waste than the samples degraded without controlled leachate recirculation. XRD spectra also confirmed to a greater extent of mineralization in the waste samples degraded under leachate recirculation with controlled pH. Comparison of XRD spectra of two types of wastes pointed out higher degree of mineralization in organic solid waste as compared to municipal solid waste.

  17. Anaerobic degradation of dairy wastewater in intermittent UASB reactors: influence of effluent recirculation.

    Science.gov (United States)

    Couras, C S; Louros, V L; Gameiro, T; Alves, N; Silva, A; Capela, M I; Arroja, L M; Nadais, H

    2015-01-01

    This work studied the influence of effluent recirculation upon the kinetics of anaerobic degradation of dairy wastewater in the feedless phase of intermittent upflow anaerobic sludge bed (UASB) reactors. Several laboratory-scale tests were performed with different organic loads in closed circuit UASB reactors inoculated with adapted flocculent sludge. The data obtained were used for determination of specific substrate removal rates and specific methane production rates, and adjusted to kinetic models. A high initial substrate removal was observed in all tests due to adsorption of organic matter onto the anaerobic biomass which was not accompanied by biological substrate degradation as measured by methane production. Initial methane production rate was about 45% of initial soluble and colloidal substrate removal rate. This discrepancy between methane production rate and substrate removal rate was observed mainly on the first day of all experiments and was attenuated on the second day, suggesting that the feedless period of intermittent UASB reactors treating dairy wastewater should be longer than one day. Effluent recirculation expressively raised the rate of removal of soluble and colloidal substrate and methane productivity, as compared with results for similar assays in batch reactors without recirculation. The observed bed expansion was due to the biogas production and the application of effluent recirculation led to a sludge bed contraction after all the substrates were degraded. The settleability of the anaerobic sludge improved by the introduction of effluent recirculation this effect being more pronounced for the higher loads.

  18. Effect of recirculation rate on methane production and SEBAR system performance using active stage digester.

    Science.gov (United States)

    Tubtong, Cheevanuch; Towprayoon, Sirintornthep; Connor, Michael Anthony; Chaiprasert, Pawinee; Nopharatana, Annop

    2010-09-01

    A project was undertaken to examine the feasibility of treating organic wastes from Thai fruit and vegetable markets using the sequential batch anaerobic digester (SEBAR) approach. A key feature of the SEBAR system is the regular interchanging, or recirculation, of portions of leachate between each freshly filled digester and a support digester to which it is coupled until it is ready to operate independently. Leachate transfer from this support digester to the fresh waste digester provides additional alkalinity to help counteract the effects of early high acid release rates; it also helps build a balanced microbial population in the fresh waste digester. To optimize the leachate recirculation process, the effect of varying the quantities of leachate interchanged between freshly filled waste digesters and the still highly active support digesters to which they were coupled was studied. It was found that increasing the recirculation rate accelerated the onset of both waste degradation and methane production. The increasing of recirculation rate from 10% to 20% and 10% to 30% could reduce the SEBAR cycle period by approximately 7% and 22% without significant reduction in the amount of methane obtained from the systems. The methane yields were 0.0063, 0.0068 and 0.0077 l g(-1) VS added in the NEW digester per day using leachate recirculation rates of 10%, 20% and 30%, respectively. This finding has potentially important practical and economic implications for those using the SEBAR system to add value to market waste.

  19. Prediction of flow recirculation in a blanket assembly under worst-case natural-convection conditions

    International Nuclear Information System (INIS)

    Khan, E.U.; Rector, D.R.

    1982-01-01

    Reactor fuel and blanket assemblies within a Liquid Metal Fast Breeder Reactor (LMFBR) can be subjected to severe radial heat flux gradients. At low-flow conditions, with power-to-flow ratios of nearly the same magnitude as design conditions, buoyancy forces cause flow redistribution to the side of a bundle with the higher heat generation rate. Recirculation of fluid within a rod bundle can occur during a natural convection transient because of the combined effect of flow coastdown and buoyancy-induced redistribution. An important concern is whether recirculation leads to high coolant temperatures. For this reason, the COBRA-WC code was developed with the capability of modeling recirculating flows. Experiments have been conducted in a 2 x 6 rod bundle for flow and power transients to study recirculation in the mixed-convection (forced cooled) and natural-convection regimes. The data base developed was used to validate the recirculation module in the COBRA-WC code. COBRA-WC code calculations were made to predict flow and temperature distributions in a typical LMFBR blanket assembly for the worst-case, natural-circulation transient

  20. Define of internal recirculation coefficient for biological wastewater treatment in anoxic and aerobic bioreactors

    Science.gov (United States)

    Rossinskyi, Volodymyr

    2018-02-01

    The biological wastewater treatment technologies in anoxic and aerobic bioreactors with recycle of sludge mixture are used for the effective removal of organic compounds from wastewater. The change rate of sludge mixture recirculation between bioreactors leads to a change and redistribution of concentrations of organic compounds in sludge mixture in bioreactors and change hydrodynamic regimes in bioreactors. Determination of the coefficient of internal recirculation of sludge mixture between bioreactors is important for the choice of technological parameters of biological treatment (wastewater treatment duration in anoxic and aerobic bioreactors, flow capacity of recirculation pumps). Determination of the coefficient of internal recirculation of sludge mixture requires integrated consideration of hydrodynamic parameter (flow rate), kinetic parameter (rate of oxidation of organic compounds) and physical-chemical parameter of wastewater (concentration of organic compounds). The conducted numerical experiment from the proposed mathematical equations allowed to obtain analytical dependences of the coefficient of internal recirculation sludge mixture between bioreactors on the concentration of organic compounds in wastewater, the duration of wastewater treatment in bioreactors.

  1. 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.

  2. Lightning-produced NOx in an explicit electrical scheme: a STERAO case study

    Science.gov (United States)

    Barthe, C.; Pinty, J.; Mari, C.

    2006-12-01

    An explicit lightning-produced nitrogen oxide scheme has been implemented in the French mesoscale model Meso-NH. The electrical scheme simulates explicitly the whole electric charge life cycle: charge separation, transfer, transport and neutralization by lightning flashes. The frequency and the 3D morphology of the lightning flashes are reproduced realistically. Therefore, fresh nitrogen oxide molecules can be added along the complex flash path as a function of the pressure, as suggested by results from laboratory experiments. No integral constraint on the total LNOx production at the cloud scale is added. The scheme is tested on the 10 July 1996, STERAO (Stratosphere-Troposphere Experiment-Radiation, Aerosols, and Ozone) storm. The model reproduces many features of the observed increase of electrical activity and LNOx flux through the anvil between the multicell and supercell stages. A large amount of LNOx is selectively produced in the upper part of the cells close to the updraft cores. Instantaneous peak concentrations exceed a few ppbv, as observed. The computed flux of NOx across the anvil compares favorably with the observations. The NOx production is estimated to 36 moles per lightning flash.

  3. 40 CFR 75.19 - Optional SO2, NOX, and CO2 emissions calculation for low mass emissions (LME) units.

    Science.gov (United States)

    2010-07-01

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

  4. Saponification pretreatment and solids recirculation as a new anaerobic process for the treatment of slaughterhouse waste.

    Science.gov (United States)

    Affes, R; Palatsi, J; Flotats, X; Carrère, H; Steyer, J P; Battimelli, A

    2013-03-01

    Different configurations of anaerobic process, adapted to the treatment of solid slaughterhouse fatty waste, were proposed and evaluated in this study. The tested configurations are based on the combination of anaerobic digestion with/without waste saponification pretreatment (70 °C during 60 min) and with/without recirculation of the digestate solid fraction (ratio=20% w/w). After an acclimation period of substrate pulses-feeding cycles, the reactors were operated in a semi-continuous feeding mode, increasing organic loading rates along experimental time. The degradation of the raw substrate was shown to be the bottleneck of the whole process, obtaining the best performance and process yields in the reactor equipped with waste pretreatment and solids recirculation. Saponification promoted the emulsification and bioavailability of solid fatty residues, while recirculation of solids minimized the substrate/biomass wash-out and induced microbial adaptation to the treatment of fatty substrates. Copyright © 2013 Elsevier Ltd. All rights reserved.

  5. Development of technique to apply induction heating stress improvement to recirculation inlet nozzle

    International Nuclear Information System (INIS)

    Chiba, Kunihiko; Nihei, Kenichi; Ootaka, Minoru

    2009-01-01

    Stress corrosion cracking (SCC) have been found in the primary loop recirculation (PLR) systems of boiling water reactors (BWR). Residual stress in welding heat-affected zone is one of the factors of SCC, and the residual stress improvement is one of the most effective methods to prevent SCC. Induction heating stress improvement (IHSI) is one of the techniques to improve reduce residual stress. However, it is difficult to apply IHSI to the place such as the recirculation inlet nozzle where the flow stagnates. In this present study, the technique to apply IHSI to the recirculation inlet nozzle was developed using water jet which blowed into the crevice between the nozzle safe end and the thermal sleeve. (author)

  6. Thermodynamic Model for Updraft Gasifier with External Recirculation of Pyrolysis Gas

    Directory of Open Access Journals (Sweden)

    Fajri Vidian

    2016-01-01

    Full Text Available Most of the thermodynamic modeling of gasification for updraft gasifier uses one process of decomposition (decomposition of fuel. In the present study, a thermodynamic model which uses two processes of decomposition (decomposition of fuel and char is used. The model is implemented in modification of updraft gasifier with external recirculation of pyrolysis gas to the combustion zone and the gas flowing out from the side stream (reduction zone in the updraft gasifier. The goal of the model obtains the influences of amount of recirculation pyrolysis gas fraction to combustion zone on combustible gas and tar. The significant results of modification updraft are that the increases amount of recirculation of pyrolysis gas will increase the composition of H2 and reduce the composition of tar; then the composition of CO and CH4 is dependent on equivalence ratio. The results of the model for combustible gas composition are compared with previous study.

  7. Method and apparatus for control of coherent synchrotron radiation effects during recirculation with bunch compression

    Science.gov (United States)

    Douglas, David R; Tennant, Christopher

    2015-11-10

    A modulated-bending recirculating system that avoids CSR-driven breakdown in emittance compensation by redistributing the bending along the beamline. The modulated-bending recirculating system includes a) larger angles of bending in initial FODO cells, thereby enhancing the impact of CSR early on in the beam line while the bunch is long, and 2) a decreased bending angle in the final FODO cells, reducing the effect of CSR while the bunch is short. The invention describes a method for controlling the effects of CSR during recirculation and bunch compression including a) correcting chromatic aberrations, b) correcting lattice and CSR-induced curvature in the longitudinal phase space by compensating T.sub.566, and c) using lattice perturbations to compensate obvious linear correlations x-dp/p and x'-dp/p.

  8. Control oriented modeling of ejector in anode gas recirculation solid oxygen fuel cell systems

    International Nuclear Information System (INIS)

    Zhu Yinhai; Li Yanzhong; Cai Wenjian

    2011-01-01

    A one-equation model is proposed for fuel ejector in anode gas recirculation solid oxide fuel cell (SOFC) system. Firstly, the fundamental governing equations are established by employing the thermodynamic, fluid dynamic principles and chemical constraints inside the ejector; secondly, the one-equation model is derived by using the parameter analysis and lumped-parameter method. Finally, the computational fluid dynamics (CFD) technique is employed to obtain the source data for determining the model parameters. The effectiveness of the model is studied under a wide range of operation conditions. The effect of ejector performance on the anode gas recirculation SOFC system is also discussed. The presented model, which only contains four constant parameters, is useful in real-time control and optimization of fuel ejector in the anode gas recirculation SOFC system.

  9. Further development of the V-code for recirculating linear accelerator simulations

    Energy Technology Data Exchange (ETDEWEB)

    Franke, Sylvain; Ackermann, Wolfgang; Weiland, Thomas [Institut fuer Theorie Elektromagnetischer Felder, Technische Universitaet Darmstadt (Germany); Eichhorn, Ralf; Hug, Florian; Kleinmann, Michaela; Platz, Markus [Institut fuer Kernphysik, Technische Universitaet Darmstadt (Germany)

    2011-07-01

    The Superconducting Darmstaedter LINear Accelerator (S-DALINAC) installed at the institute of nuclear physics (IKP) at TU Darmstadt is designed as a recirculating linear accelerator. The beam is first accelerated up to 10 MeV in the injector beam line. Then it is deflected by 180 degrees into the main linac. The linac section with eight superconducting cavities is passed up to three times, providing a maximal energy gain of 40 MeV on each passage. Due to this recirculating layout it is complicated to find an accurate setup for the various beam line elements. Fast online beam dynamics simulations can advantageously assist the operators because they provide a more detailed insight into the actual machine status. In this contribution further developments of the moment based simulation tool V-code which enables to simulate recirculating machines are presented together with simulation results.

  10. A concentrated solar cavity absorber with direct heat transfer through recirculating metallic particles

    Energy Technology Data Exchange (ETDEWEB)

    Sarker, M. R. I., E-mail: islamrabiul@yahoo.com; Saha, Manabendra, E-mail: manabendra.saha@adelaide.edu.au, E-mail: manab04me@gmail.com; Beg, R. A. [Department of Mechanical Engineering, Rajshahi University of Engineering and Technology, Rajshahi-6204 (Bangladesh)

    2016-07-12

    A recirculating flow solar particle cavity absorber (receiver) is modeled to investigate the flow behavior and heat transfer characteristics of a novel developing concept. It features a continuous recirculating flow of non-reacting metallic particles (black silicon carbide) with air which are used as a thermal enhancement medium. The aim of the present study is to numerically investigate the thermal behavior and flow characteristics of the proposed concept. The proposed solar particle receiver is modeled using two phase discrete particle model (DPM), RNG k-flow model and discrete ordinate (DO) radiation model. Numerical analysis is carried out considering a solar receiver with only air and the mixture of non-reacting particles and air as a heat transfer as well as heat carrying medium. The parametric investigation is conducted considering the incident solar flux on the receiver aperture and changing air flow rate and recirculation rate inside the receiver. A stand-alone feature of the recirculating flow solar particle receiver concept is that the particles are directly exposed to concentrated solar radiation monotonously through recirculating flow inside the receiver and results in efficient irradiation absorption and convective heat transfer to air that help to achieve high temperature air and consequently increase in thermal efficiency. This paper presents, results from the developed concept and highlights its flow behavior and potential to enhance the heat transfer from metallic particles to air by maximizing heat carrying capacity of the heat transfer medium. The imposed milestones for the present system will be helpful to understand the radiation absorption mechanism of the particles in a recirculating flow based receiver, the thermal transport between the particles, the air and the cavity, and the fluid dynamics of the air and particle in the cavity.

  11. Pressure Effects on the Thermal De-NOx Process

    DEFF Research Database (Denmark)

    Kjærgaard, Karsten; Glarborg, Peter; Dam-Johansen, Kim

    1996-01-01

    effect of the pressure but also cause a slight decrease in the NO reduction potential. The results are consistent with recent atmospheric pressure experiments of thermal de-NOx covering a wide range of reactant partial pressures. Comparisons of the experimental data with the recent chemical kinetic model......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...... at 1000 and 500 ppm, respectively At the highest pressure, CO was added to shift the regime for NO reduction to lower temperatures. The results show that the pressure affects the location and the width of the temperature window for NO reduction. As the pressure is increased, both the lower and the higher...

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

    Science.gov (United States)

    Ehara, Yoshiyasu; Amemiya, Yusuke; Yamamoto, Toshiaki

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

  13. NUTRIENTS DYNIMIC IN AN AQUAPONIC RECIRCULATING SYSTEM FOR STURGEON AND LETTUCE (LACTUCA SATIVA PRODUCTION

    Directory of Open Access Journals (Sweden)

    LORENA SFETCU

    2008-10-01

    Full Text Available Aquaponics are modern production systems, which integrate the aquaculture technology with hydroponic systems (vegetable production without soil with a goal of fructification of residual nutrients resulted from metabolic activity of fish biomass as high quality vegetable biomass sealable as ecological products. In the present study, as a first step in aquaponic recirculating systems evaluation, the authors aim to compare two types of recirculating systems: classical (hereby noted with RAS and integrated/aquaponic (RAS_A regarding water quality parameters generally, and TAN (total ammonia nitrogen production and transformation, particularly.

  14. Use of planted biofilters in integrated recirculating aquaculture-hydroponics systems in the Mekong Delta, Vietnam

    DEFF Research Database (Denmark)

    Trang, N.T.D.; Brix, Hans

    2014-01-01

    The feasibility of using planted biofilters for purification of recirculated aquaculture water in the Mekong Delta of Vietnam was assessed. The plant trenches were able to clean tilapia aquaculture water and to maintain good water quality in the fish tanks without renewal of the water. NH4-N was ...... rates of 725 kg N and 234 kg P ha-1 year-1. This research demonstrates that integrated recirculating aquaculture-hydroponics (aquaponics) systems provide significant water savings and nutrient recycling as compared with traditional fish ponds....

  15. Stability of the particle transverse motion in an electron linear accelerator with beam recirculation

    International Nuclear Information System (INIS)

    Volodin, V.A.

    1979-01-01

    Conditions, under which beam transverse instabilities appear in the electron linear accelerator (ELA) with a double particle acceleration due to excitation of asymmetric stray waves in the accelerating waveguide, and their peculiarities have been investigated. It is shown that in the ELA with beam recirculation the conditions under which the beam transverse instability appears can be determined with the help of the ''interaction function'' which depends on both the accelerating structure and the focusing in the beam transport channel. Comparison is made with characteristics of this phenomenon in conventional ELA, and possible reasons for the decrease of a starting current in ELA with recirculation are shown

  16. The impact of recirculation, ventilation and filters on secondary organic aerosols generated by indoor chemistry

    DEFF Research Database (Denmark)

    Fadeyi, M.O.; Weschler, Charles J.; Tham, K.W.

    2009-01-01

    This study examined the impact of recirculation rates (7 and 14 h(-1)), ventilation rates (1 and 2 h(-1)), and filtration on secondary organic aerosols (SOAs) generated by ozone of outdoor origin reacting with limonene of indoor origin. Experiments were conducted within a recirculating air handling......, but this was more than offset by the increased dilution of SOA derived from ozone-initiated chemistry. The presence of a particle filter (new or used) strikingly lowered SOA number and mass concentrations compared with conditions when no filter was present. Even though the particle filter in this study had only 35...

  17. 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.

  18. Effects space velocity and gas velocity on DeNOx catalyst with HC reductant; HC tenka NOx kangen shokubai no kukan sokudo oyobi gas ryusoku no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Niimura, K.; Tsujimura, K.

    1995-04-20

    Discussions were given on the hydrocarbon added reduction catalyst method to reduce NOx in diesel engine exhaust gas. An experiment was carried out with actual exhaust gas from a diesel engine by using a copper ion exchanged zeolite catalyst that has been coated on a honeycomb type substrate, and using propylene as a reductant. When the catalyst volume was changed with the exhaust gas space velocity kept constant, the NOx conversion ratio decreased as the catalyst length is decreased, and the activity shifted to the lower temperature side. The NOx reduction efficiency increased if the faster the gas flow velocity. On the other hand, if the gas flow velocity is slow, the NOx reduction can be carried out with relatively small amount of the reductant. When the catalyst volume was changed with the passing gas amount kept constant, the NOx conversion ratio decreased largely if the catalyst length is decreased. Further, the NOx reduction characteristics shift to the higher temperature side. In the catalyst length direction, the NOx reduction activity shows a relatively uniform action. However, a detailed observation reveals that the reaction heat in the catalyst is transmitted to the wake improving the activity, hence the further down the flow, the NOx conversion ratio gets higher in efficiency. 5 refs., 5 figs., 3 tabs.

  19. 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...

  20. Channel-accelerating gap interaction and beam acceleration and transport experiments with the recirculating linear accelerator (RLA)

    International Nuclear Information System (INIS)

    Mazarakis, M.G.; Smith, D.L.; Poukey, J.W.; Wagner, J.S.; Bennett, L.F.; Olson, W.R.; Turman, B.N.; Prestwich, K.R.; Wells, J.; Struve, K.

    1992-01-01

    The lifetime of the Ion Focusing Regime (IFR) channel following the pulsing of the post-accelerating gaps is critical for open-ended low energy devices. It dictates the number of allowable beam recirculations through the gaps. In the case of a closed racetrack configuration, it is significant but not as critical, since the presence of the electron beam focuses the ions and lengthens the lifetime of the ion channel. The authors have experimentally established that pulsing an accelerating gap perturbs the IFR channel. However for the parameters studied, the lifetime is long enough to allow at least four beam recirculations in a spiral device. In addition transparent grids of cusp fields positioned upstream and downstream from the gaps prevent them from perturbing the IFR channel. Experiments were performed with and without injected electron beams. For the experiments investigating the IFR channel interaction with the accelerating gap, the injector was removed and the beam line was extended downstream and upstream from the accelerating cavity. Only the first straight section of the RLA with one accelerating cavity (ET-2) was utilized. The acceleration and transport experiments were performed utilizing two injectors: first the low energy 1.3-MV Isolated Blumlein (IB) injector and most recently the new 4-MV 20-kA injector. Beams of 6--20 kA current were produced and successfully transported and accelerated through the ET-2 post-accelerating gap. For both injectors an apertured non-immersed ion-focused foilless diode was selected among various options. It is the simplest and easiest to operate and can be adjusted to provide variable beam impedance loads to the injector. The transport efficiencies were 90% for the low energy injector and 100% for the new 4-MV injector. The beam Gaussian profile and radius (5 mm) remain the same through acceleration. Experimental results will be presented and compared with numerical simulations

  1. 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%.

  2. Regulation of Nox enzymes expression in vascular pathophysiology: Focusing on transcription factors and epigenetic mechanisms

    Directory of Open Access Journals (Sweden)

    Simona-Adriana Manea

    2015-08-01

    Full Text Available 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.

  3. Human skin is protected by four functionally and phenotypically discrete populations of resident and recirculating memory T cells

    NARCIS (Netherlands)

    Watanabe, Rei; Gehad, Ahmed; Yang, Chao; Scott, Laura L.; Teague, Jessica E.; Schlapbach, Christoph; Elco, Christopher P.; Huang, Victor; Matos, Tiago R.; Kupper, Thomas S.; Clark, Rachael A.

    2015-01-01

    The skin of an adult human contains about 20 billion memory T cells. Epithelial barrier tissues are infiltrated by a combination of resident and recirculating T cells in mice, but the relative proportions and functional activities of resident versus recirculating T cells have not been evaluated in

  4. The accumulation of substances in Recirculating Aquaculture Systems (RAS) affects embryonic and larval development in common carp Cyprinus carpio

    NARCIS (Netherlands)

    Martins, C.I.; Pristin, M.G.; Ende, S.S.W.; Eding, E.H.; Verreth, J.A.J.

    2009-01-01

    The accumulation of substances in Recirculating Aquaculture Systems (RAS) may impair the growth and welfare of fish. To test the severity of contaminants accumulated in RAS, early-life stages of fish were used. Ultrafiltered water from two Recirculating Aquaculture Systems (RAS), one RAS with a high

  5. Determination of the NOx Loading of an Automotive Lean NOx Trap by Directly Monitoring the Electrical Properties of the Catalyst Material Itself

    Directory of Open Access Journals (Sweden)

    Ralf Moos

    2011-08-01

    Full Text Available 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.

  6. NOx Emission Reduction by Oscillating Combustion

    Energy Technology Data Exchange (ETDEWEB)

    John C. Wagner

    2004-03-31

    attributes of oscillating combustion and on the results of an earlier project at GTI and Air Liquide, to determine which applications for oscillating combustion would show the greatest probability for technical success and greatest probability for market acceptability. The market study indicated that furnaces in the steel, glass, and metal melting industries would perform well in both categories. These findings guided the selection of burners for laboratory testing and, with the results of the laboratory testing, guided the selection of field test sites.

  7. NOx Emission Reduction by Oscillating combustion

    Energy Technology Data Exchange (ETDEWEB)

    Institute of Gas Technology

    2004-01-30

    attributes of oscillating combustion and on the results of an earlier project at GTI and Air Liquide, to determine which applications for oscillating combustion would show the greatest probability for technical success and greatest probability for market acceptability. The market study indicated that furnaces in the steel, glass, and metal melting industries would perform well in both categories. These findings guided the selection of burners for laboratory testing and, with the results of the laboratory testing, guided the selection of field test sites.

  8. 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

  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. NOx emissions trading: Precursor to future growth

    International Nuclear Information System (INIS)

    Colella, A.

    1993-01-01

    Title I of the Clean Air Act Amendments (CAAA) of 1990 specified the framework for enhanced regulation in ozone non-attainment areas with increasingly stringent requirements dependent on the area classification - marginal, moderate, serious, severe or extreme. Before the CAAA were passed, only volatile organic compounds (VOCs) were regulated as precursors to ozone formation, Now, by statute, emissions of nitrogen oxides (NO x ) are also regulated as ozone precursor. Under the CAAA, new sources and modifications of existing sources are subject to Title I permitting requirements in ozone non-attainment areas if emissions of NO x and/or VOCs exceed certain triggering levels. For many new or facility expansion projects, especially power generation, the NO x thresholds are easily exceeded thus triggering Title I non-attainment new source review which requires application of control technology to new equipment which results in the Lowest Achievable Emission Rate (LAER), and securing emission reductions either internally or from other major sources to offset the increased emission from the new or modified source. The selection of a LAER technology is generally within an applicant's control. An applicant can determine up-front the engineering and cost considerations associated with LAER technology is assessing a project's viability. However, without a clear source of emission offsets of a means to secure them, assessing project viability could be difficult if not impossible. No available emission offsets means no industrial growth. For sources of NO x undergoing Title I new source review, a regional or state banking system that facilitates NO x emissions trading is needed as a precursor to future growth. This paper presents an overview of EPA's Emissions Trading Policy and Title I new source review offset provisions. Industry's concerns about emissions trading and recommendations for future trading programs are presented

  11. New Jersey proposes rule reducing NOx emissions

    International Nuclear Information System (INIS)

    Anon.

    1993-01-01

    The New Jersey Department of Environmental Protection and Energy has proposed a rule requiring utility and industrial sources to significantly reduce their emission levels of nitrogen oxide (NO x ). If approved, it will be the first major rule mandated by the Clean Air Act Amendments of 1990 to affect New Jersey's stationary sources of these air pollutants - primarily electric generating utilities and other large fossil fuel burning facilities. The proposed rule requires all facilities with the potential to emit 25 tons or more of NO x each year to install reasonably available control technology by May 30, 1995. According to Richard Sinding, the environment and energy agency's assistant commissioner for policy and planning, the rule will likely require installation of low-NO x burners or other modifications to the combustion process. Sinding says the proposed rule will reduce the State's NO x emissions by approximately 30,000 tons a year, roughly 30 percent from current levels from these stationary sources. The pollution prevention measures are estimated to cost approximately $1,000 for each ton of NO x removed. The state energy agency estimates the average residential utility customer will see an increase in the monthly electric bill of about 50 cents. The agency said the proposed regulation includes provisions to make implementation more flexible and less costly for achieving the NO x reductions. It has approved the use of natural gas during the ozone season if low-NO x burners are not available. Additionally, emissions may be averaged from all units at the same utility or company location, effectively allowing a company to select the most cost-effective method of achieving the required emissions reductions

  12. Evolutionary origin and function of NOX4-art, an arthropod specific NADPH oxidase.

    Science.gov (United States)

    Gandara, Ana Caroline Paiva; Torres, André; Bahia, Ana Cristina; Oliveira, Pedro L; Schama, Renata

    2017-03-29

    NADPH oxidases (NOX) are ROS producing enzymes that perform essential roles in cell physiology, including cell signaling and antimicrobial defense. This gene family is present in most eukaryotes, suggesting a common ancestor. To date, only a limited number of phylogenetic studies of metazoan NOXes have been performed, with few arthropod genes. In arthropods, only NOX5 and DUOX genes have been found and a gene called NOXm was found in mosquitoes but its origin and function has not been examined. In this study, we analyzed the evolution of this gene family in arthropods. A thorough search of genomes and transcriptomes was performed enabling us to browse most branches of arthropod phylogeny. We have found that the subfamilies NOX5 and DUOX are present in all arthropod groups. We also show that a NOX gene, closely related to NOX4 and previously found only in mosquitoes (NOXm), can also be found in other taxonomic groups, leading us to rename it as NOX4-art. Although the accessory protein p22-phox, essential for NOX1-4 activation, was not found in any of the arthropods studied, NOX4-art of Aedes aegypti encodes an active protein that produces H 2 O 2 . Although NOX4-art has been lost in a number of arthropod lineages, it has all the domains and many signature residues and motifs necessary for ROS production and, when silenced, H 2 O 2 production is considerably diminished in A. aegypti cells. Combining all bioinformatic analyses and laboratory work we have reached interesting conclusions regarding arthropod NOX gene family evolution. NOX5 and DUOX are present in all arthropod lineages but it seems that a NOX2-like gene was lost in the ancestral lineage leading to Ecdysozoa. The NOX4-art gene originated from a NOX4-like ancestor and is functional. Although no p22-phox was observed in arthropods, there was no evidence of neo-functionalization and this gene probably produces H 2 O 2 as in other metazoan NOX4 genes. Although functional and present in the genomes of many

  13. Reduced chemical kinetic mechanisms for NOx emission prediction in biomass combustion

    DEFF Research Database (Denmark)

    Houshfar, Ehsan; Skreiberg, Øyvind; Glarborg, Peter

    2012-01-01

    Because of the complex composition of biomass, the chemical mechanism contains many different species and therefore a large number of reactions. Although biomass gas‐phase combustion is fairly well researched and understood, the proposed mechanisms are still complex and need very long computational...... time and powerful hardware resources. A reduction of the mechanism for biomass volatile oxidation has therefore been performed to avoid these difficulties. The selected detailed mechanism in this study contains 81 species and 703 elementary reactions. Necessity analysis is used to determine which...... reactions and chemical species, that is, 35 species and 198 reactions, corresponding to 72% reduction in the number of reactions and, therefore, improving the computational time considerably. Yet, the model based on the reduced mechanism predicts correctly concentrations of NOx and CO that are essentially...

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

    Directory of Open Access Journals (Sweden)

    Xiaolong Tang

    2013-01-01

    Full Text Available 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.

  15. Failure investigation of stem of valve disc in reactor recirculation system of TAPS Unit-1

    International Nuclear Information System (INIS)

    Ramadasan, E.; Bahl, J.K.; Sivaramakrishnan, K.S.

    1986-01-01

    Failure analysis was carried out of failed 17-4 PH stainless steel stem of the valve disc in reactor recirculation system of Unit-1 of Tarapur Atomic Power Station. The examination revealed that the stem failed due to fatigue, accelerated by corrosion. Recommendations have been made to avoid such failures. (author)

  16. Development of FET-switched induction accelerator cells for heavy-ion fusion recirculators

    International Nuclear Information System (INIS)

    Newton, M.A.; Cravey, W.R.; Hawkins, S.A.; Kirbie, H.C.; Ollis, C.W.

    1993-01-01

    The ''recirculator,'' a recirculating heavy-ion induction accelerator, has been identified as a promising approach for an inertial fusion driver. One of the technical challenges to building a recirculator is the requirement for a modulator that can drive the induction accelerator cells at repetition rates ≥ 100 kHz with variable pulse width and pulse repetition rate capability. A high repetition rate modulator and cell is presently being developed for use on a proposed heavy-ion recirculator. The goal is to develop an array of field-effect transistors to switch 5 kV, 1 μs pulses onto a Metglas induction core at pulse rates exceeding 100 kHz. Each transistor in the array is driven by a fiber-optic isolated gate signal that is powered by a dc/dc converter. The circuit architecture provides for core reset between pulses and produces bursts of pulses that are variable in pulse width and prf. The transistor switching array, energy storage capacitors, reset circuit and cell core are all combined into a single compact, low-impedance package. Progress of this development work will be presented with supporting data

  17. Steroids accumulate in the rearing water of commercial recirculating aquaculture systems

    NARCIS (Netherlands)

    Mota, V.C.; Martins, C.I.; Eding, E.H.; Canário, A.V.M.; Verreth, J.A.J.

    2014-01-01

    Little information is available on steroid concentrations in the rearing water of aquaculture systems and whether they accumulate in recirculating aquaculture systems (RAS). Therefore this study aimed at determining (1) the concentrations and variation of cortisol and sex steroids in RAS, (2) the

  18. Bacterial activity dynamics in the water phase during start-up of recirculating aquaculture systems

    DEFF Research Database (Denmark)

    Rojas-Tirado, Paula Andrea; Pedersen, Per Bovbjerg; Pedersen, Lars-Flemming

    2017-01-01

    tMicrobial water quality in recirculating aquaculture systems (RAS) is important for successful RAS opera-tion but difficult to assess and control. There is a need to identify factors affecting changes in the bacterialdynamics – in terms of abundance and activity – to get the information needed...

  19. Removal of nitrogen by Algal Turf Scrubber Technology in recirculating aquaculture system

    NARCIS (Netherlands)

    Valeta, J.; Verdegem, M.C.J.

    2015-01-01

    Ongoing research in recirculation aquaculture focuses on evaluating and improving the purification potential of different types of filters. Algal Turf Scrubber (ATS) are special as they combine sedimentation and biofiltration. An ATS was subjected to high nutrient loads of catfish effluent to

  20. Study of atmospheric stagnation, recirculation, and ventilation potential at Narora Atomic Power Station site

    International Nuclear Information System (INIS)

    Kumar, Deepak; Kumar, Avinash; Kumar, Vimal; Rao, K.S.; Kumar, Jaivender; Ravi, P.M.

    2011-01-01

    Atmosphere is an important pathway to be considered in assessment of the environmental impact of radioactivity releases from nuclear facilities. Estimation of concentration of released effluents in air and possible ground contamination needs an understanding of relevant atmospheric dispersion. This article describes the meteorological characteristics of Narora Atomic Power Station (NAPS) site by using the integral parameters developed by Allwine and Whiteman. Meteorological data measured during the period 2006-2010 were analyzed. The integral quantities related to the occurrence of stagnation, recirculation, and ventilation characteristics were studied for NAPS site to assess the dilution potential of the atmosphere. Wind run and recirculation factors were calculated for a 24-h transport time using 5 years of hourly surface measurements of wind speed and direction. The occurrence of stagnation, recirculation, and ventilation characteristics during 2006-2010 at NAPS site is observed to be 33.8% of the time, 19.5% of the time, and 34.7% of the time, respectively. The presence of strong winds with predominant wind direction NW and WNW during winter and summer seasons leads to higher ventilation (48.1% and 44.3%) and recirculation (32.6% of the summer season). The presence of light winds and more dispersed winds during prewinter season with predominant wind directions W and WNW results in more stagnation (59.7% of the prewinter season). Thus, this study will serve as an essential meteorological tool to understand the transport mechanism of atmospheric radioactive effluent releases from any nuclear industry. (author)

  1. Experimental Bleaching of a Reef-Building Coral Using a Simplified Recirculating Laboratory Exposure System

    Science.gov (United States)

    Determining stressor-response relationships in reef building corals is a critical need for researchers because of global declines in coral reef ecosystems. A simplified recirculating coral exposure system for laboratory testing of a diversity of species and morphologies of reef b...

  2. Maintenance experience on reactor recirculation pumps at Tarapur Atomic Power Station

    International Nuclear Information System (INIS)

    Singh, A.K.

    1995-01-01

    Reactor recirculation pumps at Tarapur Atomic Power Station (TAPS) are vertical, single stage centrifugal pumps having mechanical shaft seals and are driven by vertical mounted 3.3 kV, 3 phase, 1500 h.p. electric motors. During these years of operation TAPS has gained enough experience and expertise on the maintenance of reactor recirculation pumps which are dealt in this article. Failure of mechanical shaft seals, damage on pump carbon bearings, motor winding insulation failures and motor shaft damage have been the main areas of concern on recirculation pump. A detailed procedure step by step with component sketches has helped in eliminating errors during shaft seal assembly and installation. Pressure breakdown devices in seal assembly were rebuilt. Additional coolant water injection for shaft seal cooling was provided. These measures have helped in extending the reactor recirculation pump seal life. Pump bearing problems were mainly due to failure of anti-rotation pins and dowel pins of bearing assembly. These pins were redesigned and strengthened. Motor stator winding insulation failures were detected. Stator winding replacement program has been taken up on regular basis to avoid winding insulation failure due to aging. 3 refs., 2 tabs., 7 figs

  3. Observations on side-swimming rainbow trout Oncorhynchus mykiss in water recirculation aquaculture systems

    Science.gov (United States)

    During a controlled 6-month study using six replicated water recirculation aquaculture systems (WRAS), it was observed that rainbow trout Oncorhynchus mykiss in all WRAS exhibited a higher-than-normal prevalence of side-swimming (i.e. controlled, forward swimming, but with misaligned orientation suc...

  4. Reliability analysis of air recirculation and refrigeration systems of Angra-1 reactor contaiment: a reevaluation

    International Nuclear Information System (INIS)

    Oliveira, L.F.S. de; Fleming, P.V.; Frutuoso e Melo, P.F.F.

    1983-01-01

    A realiability analysis of the air refrigeration and recirculation containment systems (ARRCS) of Angra-1 nuclear power plants, were done, aiming to evaluate the probabilities of occurence of a several accident. The systems were analysed for a 24 hours accident, including time failures and demand failures [pt

  5. Classification of scrap material from nuclear power plants as acceptable for recirculation

    International Nuclear Information System (INIS)

    Bergman, C.

    1983-06-01

    The Swedish National Institute of Radiation Protection has in a principal decision accepted that scrap material from nuclear power plants, that contains or may contain radioactive material, can be recirculated. The document is an English translation of the background material for the Board meeting decision and gives some guide-lines for the authority when dealing with this questions. (author)

  6. New developments in recirculating aquaculture systems in Europe: a perspective on environmental sustainability

    NARCIS (Netherlands)

    Martins, C.I.; Eding, E.H.; Verdegem, M.C.J.; Heinsbroek, L.T.N.; Schneider, O.; Blancheton, J.P.; Roque dÓrbcastel, E.; Verreth, J.A.J.

    2010-01-01

    The dual objective of sustainable aquaculture, i.e., to produce food while sustaining natural resources is achieved only when production systems with a minimum ecological impact are used. Recirculating aquaculture systems (RASs) provide opportunities to reduce water usage and to improve waste

  7. The Effect of Effluent Recirculation in a Semi-Continuous Two-Stage Anaerobic Digestion System

    Directory of Open Access Journals (Sweden)

    Karthik Rajendran

    2013-06-01

    Full Text Available The effect of recirculation in increasing organic loading rate (OLR and decreasing hydraulic retention time (HRT in a semi-continuous two-stage anaerobic digestion system using stirred tank reactor (CSTR and an upflow anaerobic sludge bed (UASB was evaluated. Two-parallel processes were in operation for 100 days, one with recirculation (closed system and the other without recirculation (open system. For this purpose, two structurally different carbohydrate-based substrates were used; starch and cotton. The digestion of starch and cotton in the closed system resulted in production of 91% and 80% of the theoretical methane yield during the first 60 days. In contrast, in the open system the methane yield was decreased to 82% and 56% of the theoretical value, for starch and cotton, respectively. The OLR could successfully be increased to 4 gVS/L/day for cotton and 10 gVS/L/day for starch. It is concluded that the recirculation supports the microorganisms for effective hydrolysis of polyhydrocarbons in CSTR and to preserve the nutrients in the system at higher OLRs, thereby improving the overall performance and stability of the process.

  8. Adoption of Recirculating Aquaculture Systems in Pangasius Farms: A Choice Experiment

    NARCIS (Netherlands)

    Pham, T.A.N.; Gielen-Meuwissen, M.P.M.; Le, T.T.; Bosma, R.H.; Oude Lansink, A.G.J.M.

    2015-01-01

    A growing number of European customers’ demands certified pangasius such as ASC in order to ensure sustainable production. Implementing Recirculating Aquaculture Systems (RAS) contributes to an improved water quality, a key issue in achieving ASC certification. This study uses a choice experiment to

  9. Adoption of Recirculating Aquaculture Systems in Large Pangasius Farms: A Choice Experiment

    NARCIS (Netherlands)

    Pham, T.A.N.; Gielen-Meuwissen, M.P.M.; Le, T.C.; Verreth, J.A.J.; Bosma, R.H.; Oude Lansink, A.G.J.M.

    2016-01-01

    A growing number of European customers’ demands certified pangasius such as ASC in order to ensure sustainable production. Implementing Recirculating Aquaculture Systems (RAS) contributes to an improved water quality, a key issue in achieving ASC certification. This study uses a choice experiment to

  10. Anaerobic Digestion of the Organic Fraction of Municipal Solid Waste With Recirculation of Process Water

    DEFF Research Database (Denmark)

    Hartmann, H.; Angelidaki, Irini; Ahring, Birgitte Kiær

    2001-01-01

    A new concept of a wet anaerobic digestion treatment of the organic fraction of municipal solid waste (OFMSW) is investigated. Once the waste is diluted with water, the entire liquid fraction of the effluent is recirculated and used as process water for dilution of the waste. This enables a well...

  11. Evaluation of a rainbow trout (Oncorhynchus mikyss culture water recirculating system

    Directory of Open Access Journals (Sweden)

    Iván Sánchez O.

    2014-09-01

    Full Text Available Objective. To evaluate a water recirculation system for rainbow trout fish cultures at the recirculating laboratory of the Aquaculture Engineering Production Program of University of Nariño. Materials and Methods. 324 rainbow trout (Oncorhynchus mikyss fries were cultured in 12 plastic tanks with a capacity of 250 L in an aquaculture recirculating system the treatment system of which was made up by a conventional sedimentation tank, a fixed stand upflow biofilter with recycled PVC tube pieces and a natural degassing system; the sedimentation unit effluent was pumped up to a reservoir tank using a 2 HP centrifugal pump after being subject to gravity through the biofilter and to be then distributed to the 12 culture units to which a constant amount of air from a blower was injected. Results. The water treatment system removed 31% of total suspended solids, 9.5% of total ammonia nitrogen, and increased dissolved oxygen to the final effluent in 6.5%. An increase of 305% in biomass was calculated during 75 days, the mortality percentage registered throughout the study period was 4.9%. Conclusions. The water treatment system maintained the physicochemical water quality parameters within the values recommended for the species. The increase in weight and size, food conversion, mortality and biomass production reported normal values for rainbow trout fish culture in recirculating systems.

  12. Evaluation of commercial marine fish feeds for production of juvenile cobia in recirculating aquaculture systems

    Science.gov (United States)

    The effect of feeding three commercially available diets manufactured by three U.S. feed companies on production characteristics and body composition of juvenile cobia Rachycentron canadum reared in recirculating aquaculture systems (RAS) was evaluated in a 57 d growth trial. Juvenile cobia (26.7 +...

  13. A New Eulerian Model for Turbulent Evaporating Sprays in Recirculating Flows

    NARCIS (Netherlands)

    Wittig, S.; Hallmann, M.; Scheurlen, M.; Schmehl, R.

    1993-01-01

    A new Eulerian model for the computation of turbulent evaporating sprays in recirculating flows is derived. It comprises droplet heating and evaporation processes by solving separate transport equations for the droplet's temperature and diameter. Full coupling of the droplet and the gaseous phase is

  14. Analysis of heat recovery from a spray dryer by recirculation of exhaust air

    International Nuclear Information System (INIS)

    Golman, Boris; Julklang, Wittaya

    2014-01-01

    Highlights: • We study a spray dryer with heat recovery by partial recirculation of exhaust air. • We examine effects of process parameters on energy efficiency and energy savings. • Decreasing drying air temperature and flow rate will increase energy efficiency. • Increasing recirculation ratio and slurry feed rate will increase energy efficiency. - Abstract: Model simulations were employed to investigate the influences of process parameters on the energy recovery in spray drying process that partially recycle the exhaust drying gas. The energy efficiency and energy saving were studied for various values of recirculation ratios with respect to the temperature and flow rate of the drying air, slurry feed rate and concentration of slurry in spray drying of advanced ceramic materials. As a result, significant gains in energy efficiency and energy saving were obtained for a spray drying system with high recirculation ratio of exhaust air. The high slurry feed rate and the low slurry concentration, inlet drying air temperature and drying air flow rate enhanced the energy efficiency of spray drying system. However, the high energy saving was obtained in spray dryers operating at low slurry feed rate and high slurry concentration

  15. Water cortisol and testosterone in Nile tilapia (Oreochromis niloticus) recirculating aquaculture systems

    NARCIS (Netherlands)

    Mota, Vasco C.; Martins, Catarina I.M.; Eding, Ep H.; Canário, Adelino V.M.; Verreth, Johan A.J.

    2017-01-01

    The accumulation of steroids released by fish in recirculating aquaculture systems (RAS) may potentially influence their physiology and behavior. The present study examined the release rate of cortisol and testosterone by Nile tilapia, Oreochromis niloticus, and their accumulation in six identical

  16. Development of new design mechanical seal tester for Primary Loop Recirculation Pump (PLR Pump)

    International Nuclear Information System (INIS)

    Fukushima, Naoki; Koshiba, Koremutsu

    1995-01-01

    The mechanical seal for a Primary Loop Recirculation Pump (PLR Pump) is an important part of a BWR plant. This study describes a new mechanical seal tester developed to certify mechanical seal performance before installation in a PLR Pump on site. (author)

  17. The effect of leachate recirculation with enzyme cellulase addition on waste stability in landfill bioreactor

    Science.gov (United States)

    Saffira, N.; Kristanto, G. A.

    2018-01-01

    Landfill bioreactor with leachate recirculation is known to enhance waste stabilization. However, the composition of waste in Indonesia is comprised by organic waste which is lignocellulosic materials that considered take a long time to degrade under anaerobic condition. To accelerate the degradation process, enzyme addition is ought to do. Cellulase is an enzyme that can catalyse cellulose and other polysaccharide decomposition processes. Therefore, operation of waste degradation using leachate recirculation with a cellulase addition to enhance waste stabilization was investigated using anaerobic bioreactor landfill. The experiment was performed on 2 conditions; leachate recirculation with cellulase addition and recirculation only as a control. The addition of cellulase is reported to be significant in decreasing organic content, represented by volatile solid parameter. The volatile solid reduction in the cellulase augmented reactor and control reactor was 17.86% and 7.90%, respectively. Cellulase addition also resulted in the highest cellulose reduction. Settlement of the landfill in a bioreactor with enzyme addition (32.67%) was reported to be higher than the control (19.33%). Stabilization of landfill review by the decreasing rate constant of the cellulose and lignin ratio parameter was more rapidly achieved by the enzyme addition (0.014 day-1) compared to control (0.002 day-1).

  18. Multi-point optimization of recirculation flow type casing treatment in centrifugal compressors

    Science.gov (United States)

    Tun, Min Thaw; Sakaguchi, Daisaku

    2016-06-01

    High-pressure ratio and wide operating range are highly required for a turbocharger in diesel engines. A recirculation flow type casing treatment is effective for flow range enhancement of centrifugal compressors. Two ring grooves on a suction pipe and a shroud casing wall are connected by means of an annular passage and stable recirculation flow is formed at small flow rates from the downstream groove toward the upstream groove through the annular bypass. The shape of baseline recirculation flow type casing is modified and optimized by using a multi-point optimization code with a metamodel assisted evolutionary algorithm embedding a commercial CFD code CFX from ANSYS. The numerical optimization results give the optimized design of casing with improving adiabatic efficiency in wide operating flow rate range. Sensitivity analysis of design parameters as a function of efficiency has been performed. It is found that the optimized casing design provides optimized recirculation flow rate, in which an increment of entropy rise is minimized at grooves and passages of the rotating impeller.

  19. Fulminant hepatic failure following marijuana drug abuse: Molecular adsorbent recirculation system therapy

    Directory of Open Access Journals (Sweden)

    G Swarnalatha

    2013-01-01

    Full Text Available Marijuana is used for psychoactive and recreational purpose. We report a case of fulminant hepatic failure following marijuana drug abuse who recovered following artificial support systems for acute liver failure. There is no published literature of management of marijuana intoxication with molecular adsorbent recirculation system (MARS. MARS is effective and safe in patients with fulminant hepatic failure following marijuana intoxication.

  20. Effect of recirculation and regional counting rate on reliability of noninvasive bicompartmental CBF measurements

    International Nuclear Information System (INIS)

    Herholz, K.

    1985-01-01

    Based on data from routine intravenous Xe133-rCBF studies in 50 patients, using Obrist's algorithm the effect of counting rate statistics and amount of recirculating activity on reproducibility of results was investigated at five simulated counting rate levels. Dependence of the standard deviation of compartmental and noncompartmental flow parameters on recirculation and counting rate was determined by multiple linear regression analysis. Those regression equations permit determination of the optimum accuracy that may be expected from individual flow measurements. Mainly due to a delay of the start-of-fit time an exponential increase in standard deviation of flow measurements was observed as recirculation increased. At constant start-of-fit, however, a linear increase in standard deviation of compartmental flow parameters only was found, while noncompartmental results remained constant. Therefore, and in regard to other studies of potential sources of error, an upper limit of 2.5 min for the start-of-fit time and usage of noncompartmental flow parameters for measurements affected by high recirculation are suggested

  1. The impact of building recirculation rates on secondary organic aerosols generated by indoor chemistry

    DEFF Research Database (Denmark)

    Zuraimi, M.S.; Weschler, Charles J.; Tham, K.W.

    2007-01-01

    Numerous investigators have documented increases in the concentrations of airborne particles as a consequence of ozone/terpene reactions in indoor environments. This study examines the effect of building recirculation rates on the concentrations of secondary organic aerosol (SOA) resulting from r...

  2. 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.

  3. Nox2 in regulatory T cells promotes angiotensin II-induced cardiovascular remodeling.

    Science.gov (United States)

    Emmerson, Amber; Trevelin, Silvia Cellone; Mongue-Din, Heloise; Becker, Pablo D; Ortiz, Carla; Smyth, Lesley A; Peng, Qi; Elgueta, Raul; Sawyer, Greta; Ivetic, Aleksandar; Lechler, Robert I; Lombardi, Giovanna; Shah, Ajay M

    2018-04-24

    The superoxide-generating enzyme Nox2 contributes to hypertension and cardiovascular remodeling triggered by activation of the renin-angiotensin system. Multiple Nox2-expressing cells are implicated in angiotensin II (AngII)-induced pathophysiology, but the importance of Nox2 in leukocyte subsets is poorly understood. Here, we investigated the role of Nox2 in T cells, particularly Tregs. Mice globally deficient in Nox2 displayed increased numbers of Tregs in the heart at baseline whereas AngII-induced T-effector cell (Teffs) infiltration was inhibited. To investigate the role of Treg Nox2, we generated a mouse line with CD4-targeted Nox2 deficiency (Nox2fl/flCD4Cre+). These animals showed inhibition of AngII-induced hypertension and cardiac remodeling related to increased tissue-resident Tregs and reduction in infiltrating Teffs, including Th17 cells. The protection in Nox2fl/flCD4Cre+ mice was reversed by anti-CD25 Ab-depletion of Tregs. Mechanistically, Nox2-/y Tregs showed higher in vitro suppression of Teffs proliferation than WT Tregs, increased nuclear levels of FoxP3 and NF-κB, and enhanced transcription of CD25, CD39, and CD73. Adoptive transfer of Tregs confirmed that Nox2-deficient cells had greater inhibitory effects on AngII-induced heart remodeling than WT cells. These results identify a previously unrecognized role of Nox2 in modulating suppression of Tregs, which acts to enhance hypertension and cardiac remodeling.

  4. Evolutionary origin and function of NOX4-art, an arthropod specific NADPH oxidase

    OpenAIRE

    Gandara, Ana Caroline Paiva; Torres, Andr?; Bahia, Ana Cristina; Oliveira, Pedro L.; Schama, Renata

    2017-01-01

    Background NADPH oxidases (NOX) are ROS producing enzymes that perform essential roles in cell physiology, including cell signaling and antimicrobial defense. This gene family is present in most eukaryotes, suggesting a common ancestor. To date, only a limited number of phylogenetic studies of metazoan NOXes have been performed, with few arthropod genes. In arthropods, only NOX5 and DUOX genes have been found and a gene called NOXm was found in mosquitoes but its origin and function has not b...

  5. 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.

  6. Performance of Water Recirculation Loop Maintentance Components for the Advanced Spacesuit Water Membrane Evaporator

    Science.gov (United States)

    Rector, Tony; Peyton, Barbara; Steele, John W.; Bue, Grant C.; Campbell, Colin; Makinen, Janice

    2014-01-01

    Water loop maintenance components to maintain the water quality of the Advanced Spacesuit Water Membrane Evaporation (SWME) water recirculation loop have undergone a comparative performance evaluation with a second SWME water recirculation loop with no water quality maintenance. Results show the benefits of periodic water maintenance. The SWME is a heat rejection device under development at the NASA Johnson Space Center to perform thermal control for advanced spacesuits. One advantage to this technology is the potential for a significantly greater degree of tolerance to contamination when compared to the existing Sublimator technology. The driver for the evaluation of water recirculation maintenance components was to further enhance this advantage through the leveraging of fluid loop management lessonslearned from the International Space Station (ISS). A bed design that was developed for a UTAS military application, and considered for a potential ISS application with the Urine Processor Assembly, provided a low pressure drop means for water maintenance in a recirculation loop. The bed design is coupled with high capacity ion exchange resins, organic adsorbents, and a cyclic methodology developed for the Extravehicular Mobility Unit (EMU) Transport Water loop. The maintenance cycle included the use of a biocide delivery component developed for ISS to introduce a biocide in a microgravity-compatible manner for the Internal Active Thermal Control System (IATCS). The leveraging of these water maintenance technologies to the SWME recirculation loop is a unique demonstration of applying the valuable lessons learned on the ISS to the next generation of manned spaceflight Environmental Control and Life Support System (ECLSS) hardware.

  7. Performance of Water Recirculation Loop Maintenance Components for the Advanced Spacesuit Water Membrane Evaporator

    Science.gov (United States)

    Rector, Tony; Peyton, Barbara M.; Steele, John W.; Makinen, Janice; Bue, Grant C.; Campbell, Colin

    2014-01-01

    Water loop maintenance components to maintain the water quality of the Advanced Spacesuit Water Membrane Evaporation (SWME) water recirculation loop have undergone a comparative performance evaluation with a second SWME water recirculation loop with no water quality maintenance. Results show the benefits of periodic water maintenance. The SWME is a heat rejection device under development at the NASA Johnson Space Center to perform thermal control for advanced spacesuits. One advantage to this technology is the potential for a significantly greater degree of tolerance to contamination when compared to the existing Sublimator technology. The driver for the evaluation of water recirculation maintenance components was to further enhance this advantage through the leveraging of fluid loop management lessons learned from the International Space Station (ISS). A bed design that was developed for a UTAS military application, and considered for a potential ISS application with the Urine Processor Assembly, provided a low pressure drop means for water maintenance in a recirculation loop. The bed design is coupled with high capacity ion exchange resins, organic adsorbents, and a cyclic methodology developed for the Extravehicular Mobility Unit (EMU) Transport Water loop. The maintenance cycle included the use of a biocide delivery component developed for ISS to introduce a biocide in a microgravity compatible manner for the Internal Active Thermal Control System (IATCS). The leveraging of these water maintenance technologies to the SWME recirculation loop is a unique demonstration of applying the valuable lessons learned on the ISS to the next generation of manned spaceflight Environmental Control and Life Support System (ECLSS) hardware.

  8. CFD modeling of hydro-biochemical behavior of MSW subjected to leachate recirculation.

    Science.gov (United States)

    Feng, Shi-Jin; Cao, Ben-Yi; Li, An-Zheng; Chen, Hong-Xin; Zheng, Qi-Teng

    2018-02-01

    The most commonly used method of operating landfills more sustainably is to promote rapid biodegradation and stabilization of municipal solid waste (MSW) by leachate recirculation. The present study is an application of computational fluid dynamics (CFD) to the 3D modeling of leachate recirculation in bioreactor landfills using vertical wells. The objective is to model and investigate the hydrodynamic and biochemical behavior of MSW subject to leachate recirculation. The results indicate that the maximum recirculated leachate volume can be reached when vertical wells are set at the upper middle part of a landfill (H W /H T  = 0.4), and increasing the screen length can be more helpful in enlarging the influence radius than increasing the well length (an increase in H S /H W from 0.4 to 0.6 results in an increase in influence radius from 6.5 to 7.7 m). The time to reach steady state of leachate recirculation decreases with the increase in pressure head; however, the time for leachate to drain away increases with the increase in pressure head. It also showed that methanogenic biomass inoculum of 1.0 kg/m 3 can accelerate the volatile fatty acid depletion and increase the peak depletion rate to 2.7 × 10 -6  kg/m 3 /s. The degradation-induced void change parameter exerts an influence on the processes of MSW biodegradation because a smaller parameter value results in a greater increase in void space.

  9. 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.

  10. Effect of NOx level on secondary organic aerosol (SOA formation from the photooxidation of terpenes

    Directory of Open Access Journals (Sweden)

    R. C. Flagan

    2007-10-01

    Full Text Available Secondary organic aerosol (SOA formation from the photooxidation of one monoterpene (α-pinene and two sesquiterpenes (longifolene and aromadendrene is investigated in the Caltech environmental chambers. The effect of NOx on SOA formation for these biogenic hydrocarbons is evaluated by performing photooxidation experiments under varying NOx conditions. The NOx dependence of α-pinene SOA formation follows the same trend as that observed previously for a number of SOA precursors, including isoprene, in which SOA yield (defined as the ratio of the mass of organic aerosol formed to the mass of parent hydrocarbon reacted decreases as NOx level increases. The NOx dependence of SOA yield for the sesquiterpenes, longifolene and aromadendrene, however, differs from that determined for isoprene and α-pinene; the aerosol yield under high-NOx conditions substantially exceeds that under low-NOx conditions. The reversal of the NOx dependence of SOA formation for the sesquiterpenes is consistent with formation of relatively low-volatility organic nitrates, and/or the isomerization of large alkoxy radicals leading to less volatile products. Analysis of the aerosol chemical composition for longifolene confirms the presence of organic nitrates under high-NOx conditions. Consequently the formation of SOA from certain biogenic hydrocarbons such as sesquiterpenes (and possibly large anthropogenic hydrocarbons as well may be more efficient in polluted air.

  11. Low NOx combustion technologies for high-temperature natural gas combustion

    International Nuclear Information System (INIS)

    Flamme, Michael

    1999-01-01

    Because of the high process temperature which is required for some processes like glass melting and the high temperature to which the combustion air is preheated, NOx emission are extremely high. Even at these high temperatures, NOx emissions could be reduced drastically by using advanced combustion techniques such as staged combustion or flame-less oxidation, as experimental work has shown. In the case of oxy-fuel combustion, the NOx emission are also very high if conventional burners are used. The new combustion techniques achieve similar NOx reductions. (author)

  12. Evaluation of NOX emissions from TVA coal-fired power plants

    International Nuclear Information System (INIS)

    Jones, J.W.; Stamey-Hall, S.

    1991-01-01

    The paper gives results of a preliminary evaluation of nitrogen oxide (NOx) emissions from 11 Tennessee Valley Authority (TVA) coal-fired power plants. Current EPA AP-42 emission factors for NOx from coal-fired utility boilers do not account for variations either in these emissions as a function of generating unit load, or in designs of boilers of the same general type, particularly wall-fired boilers. The TVA has compiled short-term NOx emissions data from 30 units at 11 TVA coal-fired plants. These units include cyclone, cell burner, single wall, opposed wall, single tangential, and twin tangential boiler firing designs. Tests were conducted on 29 of the 30 units at high load; 18 were also tested at reduced load. NOx emissions rates were calculated for each test and compared to the calculated rate for each boiler type using AP-42. Preliminary analysis indicates that: (1) TVA cyclone-fired units emit more NOx than estimated using AP-42; (2) TVA cell burner units emit considerably more NOx than estimated; (3) most TVA single-wall-fired units emit slightly more NOx than estimated; (4) most TVA single-furnace tangentially fired units emit less NOx than estimated at high load, but the same as (or more than) estimated at reduced load; and (5) most TVA twin-furnace tangentially fired units, at high load, emit slightly more NOx than estimated using AP-42

  13. FY-2016 Methyl Iodide Higher NOx Adsorption Test Report

    Energy Technology Data Exchange (ETDEWEB)

    Soelberg, Nicholas Ray [Idaho National Lab. (INL), Idaho Falls, ID (United States); Watson, Tony Leroy [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2016-09-01

    Deep-bed methyl iodide adsorption testing has continued in Fiscal Year 2016 under the Department of Energy (DOE) Fuel Cycle Technology (FCT) Program Offgas Sigma Team to further research and advance the technical maturity of solid sorbents for capturing iodine-129 in off-gas streams during used nuclear fuel reprocessing. Adsorption testing with higher levels of NO (approximately 3,300 ppm) and NO2 (up to about 10,000 ppm) indicate that high efficiency iodine capture by silver aerogel remains possible. Maximum iodine decontamination factors (DFs, or the ratio of iodine flowrate in the sorbent bed inlet gas compared to the iodine flowrate in the outlet gas) exceeded 3,000 until bed breakthrough rapidly decreased the DF levels to as low as about 2, when the adsorption capability was near depletion. After breakthrough, nearly all of the uncaptured iodine that remains in the bed outlet gas stream is no longer in the form of the original methyl iodide. The methyl iodide molecules are cleaved in the sorbent bed, even after iodine adsorption is no longer efficient, so that uncaptured iodine is in the form of iodine species soluble in caustic scrubber solutions, and detected and reported here as diatomic I2. The mass transfer zone depths were estimated at 8 inches, somewhat deeper than the 2-5 inch range estimated for both silver aerogels and silver zeolites in prior deep-bed tests, which had lower NOx levels. The maximum iodine adsorption capacity and silver utilization for these higher NOx tests, at about 5-15% of the original sorbent mass, and about 12-35% of the total silver, respectively, were lower than for trends from prior silver aerogel and silver zeolite tests with lower NOx levels. Additional deep-bed testing and analyses are recommended to expand the database for organic iodide adsorption and increase the technical maturity if iodine adsorption processes.

  14. Automation of water supply and recirculation-filtration of water at a swimming pool using Zelio PLC

    Science.gov (United States)

    Diniş, C. M.; Popa, G. N.; Iagăr, A.

    2018-01-01

    The paper proposes the use of the Zelio PLC for the automation of the water supply and recirculation-filtration system of a swimming pool. To do this, the Zelio SR3B261BD - 24V DC with 10 digital inputs (24V DC) and 10 digital outputs (relay contacts) was used. The proposed application makes the control of the water supply pumps and the water recirculation-filtration from a swimming pool. The recirculation-filtration systems for pools and swimming pools are designed to ensure water cleaning and recirculation to achieve optimum quality and lasting service life. The water filtration process is one of the important steps in water treatment in polls and swimming pools. It consists in recirculation of the entire volume of water and begins by absorbing the water in the pool by means of a pump followed by the passing of water through the filter, disinfectant and pH dosing, and reintroducing the water back into the pool or swimming pool through the discharge holes. Filters must to work 24 hours a day to remove pollutants from pools or swimming pools users. Filtration removes suspension particles with different origins. All newly built pools and swimming pools must be fitted with water recirculation systems, and existing ones will be equipped with water recirculation and water treatment systems.

  15. Simultaneous water desalination and electricity generation in a microbial desalination cell with electrolyte recirculation for pH control

    KAUST Repository

    Qu, Youpeng

    2012-02-01

    A recirculation microbial desalination cell (rMDC) was designed and operated to allow recirculation of solutions between the anode and cathode chambers. This recirculation avoided pH imbalances that could inhibit bacterial metabolism. The maximum power density was 931±29mW/m 2 with a 50mM phosphate buffer solution (PBS) and 776±30mW/m 2 with 25mM PBS. These power densities were higher than those obtained without recirculation of 698±10mW/m 2 (50mM PBS) and 508±11mW/m 2 (25mM PBS). The salt solution (20g/L NaCl) was reduced in salinity by 34±1% (50mM) and 37±2% (25mM) with recirculation (rMDC), and by 39±1% (50mM) and 25±3% (25mM) without recirculation (MDC). These results show that electrolyte recirculation using an rMDC is an effective method to increase power and achieve efficient desalination by eliminating pH imbalances. © 2011 Elsevier Ltd.

  16. 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

  17. 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

  18. New NOx cleansing technology can reduce industry emissions

    International Nuclear Information System (INIS)

    2006-01-01

    The Norwegian, Bergen-based company ECO Energy has recently launched a new cleaning technology halving NO x emissions from industry plants without requiring large investments. Thus, governmental promises to finance NO x cleaning equipment for Norwegian industry have become less expensive to reach. ECO Energy has ensured world patent on the 'stopNOx' technology. Its method consists of adding water and urea to oil before the combustion process. The technology has been applied in Italy, reducing NO x emissions from industry in average with above 50 percent (ml)

  19. New NOx cleaning technology helps the government fulfil promise

    International Nuclear Information System (INIS)

    2006-01-01

    The Norwegian, Bergen-based company ECO Energy has recently launched a new cleaning technology halving NO x emissions from industry plants without requiring large investments. Thus, governmental promises to finance NO x cleaning equipment for Norwegian industry have become a less expensive to reach. ECO Energy has ensured world patent on the 'stopNOx' technology. Its method consists of adding water and urea to oil before the combustion process. The technology has been applied in Italy, reducing NO x emissions from industry in average with above 50 percent (ml)

  20. Cardiac and renal upregulation of Nox2 and NF-κB and repression of Nox4 and Nrf2 in season- and diabetes-mediated models of vascular oxidative stress in guinea-pig and rat.

    Science.gov (United States)

    Gajos-Draus, Anna; Duda, Monika; Beręsewicz, Andrzej

    2017-11-01

    The superoxide-forming NADPH oxidase homologues, Nox1, Nox2, and Nox5, seem to mediate the pro-atherosclerotic vascular phenotype. The hydrogen peroxide-forming Nox4 afforded vascular protection, likely via NF-E2-related factor-2 (Nrf2) activation and/or Nox2 downregulation in transgenic mice. We hypothesized that oxidative stress in the intact vasculature involves, aside from the upregulation of the superoxide-forming Noxs, the downregulation of the Nox4/Nrf2 pathway. Guinea-pigs and rats were studied either in winter or in summer, and the streptozotocin diabetic rats in winter. Plasma nitrite, and superoxide production by isolated hearts were measured, while frozen tissues served in biochemical analyses. Summer in both species and diabetes in rats downregulated myocardial Nox4 while reciprocally upregulating Nox2 and Nox5 in guinea-pigs, and Nox2 in rats. Simultaneously, myocardial Nrf2 activity and the expression of the Nrf2-directed heme oxygenase-1 and endothelial NO synthase were reduced while activity of the nuclear factor κ B (NF- κ B) and the expression of NF- κ B-directed inducible NO synthase and the vascular cell adhesion molecule-1 were increased. Cardiac superoxide production was increased while plasma nitrite was decreased reciprocally. Analogous disregulation of Noxs, Nrf2, and NF- κ B, occurred in diabetic rat kidneys. Given the diversity of the experimental settings and the uniform pattern of the responses, we speculate that: (1) chronic vascular oxidative stress is a nonspecific (model-, species-, organ-independent) response involving the induction of Nox2 (and Nox5 in guinea-pigs) and the NF- κ B pathway, and the repression of Nox4 and the Nrf2 pathway; and (2) the systems Nox2-NF- κ B and Nox4-Nrf2 regulate each other negatively. © 2017 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.