Download or read book A Study of NO subscript X Reduction by Fuel Injection Recirculation written by and published by . This book was released on 1996 with total page 119 pages. Available in PDF, EPUB and Kindle. Book excerpt: Flue-gas recirculation (FGR) is a well-known method used to control oxides of nitrogen (NO{sub X}) in industrial burner applications. Recent small- and large-scale experiments in natural-gas fired boilers have shown that introducing the recirculated flue gases with the fuel results in a much greater reduction in NO{sub X}, per unit mass of gas recirculated, in comparison to introducing the flue gases with the combustion air. That fuel injection recirculation (FIR) is more effective than windbox FGR is quite remarkable. At present, however, there is no definitive understanding of why FIR is more effective than conventional FGR. The objective of the present investigation is to ascertain whether or not chemical and/or molecular transport effects alone can explain the differences in NO{sub X} reduction observed between FIR and FGR by studying laminar diffusion flames. The purpose of studying laminar flames is to isolate chemical effects from the effects of turbulent mixing and heat transfer, which are inherent in practical boilers. Numerical simulations of H2-air and CH4-air counterflow diffusion flames using full kinetics were performed and NO{sub X} emission indices calculated for various conditions. Studies were conducted in which a N2 diluent was added either on the fuel- or air-side of the flame for conditions of either fixed initial velocities or fixed fuel mass flux. Results from these simulation studies indicate that a major factor in diluent effectiveness is the differential effect on flame zone residence times associated with fuel-side verses air-side dilution. Simulations in which flow velocities were fixed as diluent was added either to the air or fuel stream showed lower NO{sub X} emissions for air-side dilution; however, if instead, fuel mass fluxes were fixed as diluent was added, which results in an increase in the velocity of the streams, fuel-side dilution was more effective. These results were independent of whether H2 or Ch4 was used as the fuel.

Download or read book Verkehrs Regelung in der Goethe Woche written by and published by . This book was released on 1932 with total page 2 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book I A Comenii Lexicon atriale written by and published by . This book was released on 1657 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Study of NO subscript X Reduction by Fuel Injection Recirculation Final Report January 1995 June 1996 written by and published by . This book was released on 1996 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt: Flue-gas recirculation (FGR) is a well-known method used to control oxides of nitrogen (NO(subscript x)) in industrial burner applications. Recent small- and large-scale experiments in natural-gas fired boilers have shown that introducing the recirculated flue gases with the fuel results in a much greater reduction in NO(subscript x), per unit mass of gas recirculated, in comparison to introducing the flue gases with the combustion air. That fuel injection recirculation (FIR) is more effective than windbox FGR is quite remarkable. At present, however, there is no definitive understanding of why FIR is more effective than conventional FGR. The objective of the present investigation is to ascertain whether or not chemical and/or molecular transport effects alone can explain the differences in NO(subscript x) reduction observed between FIR and FGR by studying laminar diffusion flames. The purpose of studying laminar flames is to isolate chemical effects from the effects of turbulent mixing and heat transfer, which are inherent in practical boilers. The results of both the numerical simulations and the experiments suggest that, although molecular transport and chemical kinetic phenomena are affected by the location of diluent addition depending on flow conditions, the greater effectiveness of FIR over FGR in practical applications may result from differences in turbulent mixing and heat transfer. Further research is required to understand how differences in diluent-addition location affect NO(subscript x) production in turbulent flames. The present study, however, provides an underlying basis for understanding how flow conditions can affect flame chemistry. 51 figs., 7 tabs.

Download or read book A Study of NOsub X Reduction by Fuel Injection Recirculation Topical Report June December 1995 written by and published by . This book was released on 1996 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Study of NOsub X Reduction by Fuel Injection Recirculation Topical Report January 1995 May 1995 written by and published by . This book was released on 1995 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book NO subscript X Emission Controls for Heavy duty Vehicles written by National Research Council (U.S.). Motor Vehicle Nitrogen Oxides Standard Committee and published by National Academies. This book was released on 1981 with total page 136 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Feasibility and Costs of Applying NO subscript X Controls on Stationary Emission Sources in California written by P. P. Leo and published by . This book was released on 1980 with total page 342 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Assessment of Simultaneous Use of NO subscript X Control Systems on Stationary Sources in California written by J. R. Witz and published by . This book was released on 1982 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book NO subscript X Emission Controls for Heavy duty Vehicles written by and published by National Academies. This book was released on 1981 with total page 132 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book An Experimental Study of NO subscript X Recycle in the NOXSO Flue Gas Cleanup Process Quarterly Technical Progress Report October 1 December 31 1992 written by and published by . This book was released on 1992 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: All the tests planed were completed. NO2 injection tests showed higher NO(subscript x) reduction than that of NO injection at similar testing conditions. The NO(subscript x) reduction efficiency for the NO/NO2 mixture injection is higher than that for NO injection and lower than that for NO2 injection separately. The NO(subscript x) reduction efficiency is independent on the amount of injected gas (NO, NO2, or NO/NO2), but affected by the exit O2. The optimum injection location which gives higher NO(subscript x) reduction efficiency is the primary air duct. The NO(subscript x) reduction efficiency increases with the percentage of total NO injected into the primary air duct when injecting NO into both primary air duct and secondary air duct simultaneous.

Download or read book Impact of Water Injection on Emissions of Nitrogen Oxides from Aircraft Engines written by Syed Shayan Zahid and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Aircraft NO[subscript x] emissions form as a result of high-temperature combustion in the engine, and they lead to negative climate and air quality impacts. These emissions increase with temperature, so a NO[subscript x] reduction technique has been proposed where water is injected in different regions of a gas turbine engine to cool down the peak flame temperature and decrease NO[subscript x] production. In previous studies, water injection has been simulated on existing engine models instead of co-optimizing the engine cycle and design characteristics for this technology. This thesis uses pyCycle, a gas turbine cycle analysis tool, to optimize an engine cycle based on this water injection strategy and assess the performance impact of water injection on aircraft missions of varying ranges. This impact is then compared with the emissions impact of water injection estimated by PyCaSo, a combustor modeling tool to evaluate the potential benefits of this technology. It is found that for a turbofan engine, water injection has the potential to reduce NO[subscript x] emissions by up to 80% without compromising the fuel efficiency of the aircraft. Water injection upstream of the compressors yields performance benefits due to reduction in required compression work, injection downstream of the compressors incurs a penalty to fuel efficiency. The benefit of water injection for NO[subscript x] reduction in engines operating on rich front-end combustor is more than those running on lean burn configurations. For shorter range missions under 3000 km, the weight penalty due to carrying the additional water on the airplane is offset by the performance benefit of water injection upstream of the compressors depending on the amount of water injected and the engine model, whereas for longer range flights beyond 3000 km, the water weight penalty outweighs the performance benefit in most cases.

Download or read book The Reduction of NO subscript X by HNCO written by and published by . This book was released on 1992 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt: A chemical mechanism for the reduction of NO(subscript x) by HNCO has been constructed to model NO(subscript x) reduction in exhausts typical of natural gas combustion with the addition of radical boosters (fuel). Variables considered were the initial concentrations of NO, NO2, CO, O2, CH4, H2, and HNCO as well as initial temperatures. The chemical model was validated by comparing results with earlier model calculations of Miller and Bowman and with the experiments of Caton and Siebers and Lyon and Cole. Agreement with experiments was satisfactory. The reduction chemistry must be preceded by thermal ignition chemistry which generates radicals. The lowest temperature for which ignition occurs is the optimum temperature for reduction and defines the beginning of the temperature window. Reduction was not achieved for the ''natural gas exhaust'' for a reasonable residence time. Additional H2 added to the exhaust mixture enhanced reduction, but the addition of CO and CH4 did not. Under some conditions the computed sensitivity coefficient for nitrogen species and temperature exhibited self-similarity. Four reaction paths were identified which controlled the fate of the NO: the conversion of NO to NO2 via HO2, the conversion of NO2 to NO via reaction with H or O, the reduction of NO via NCO, and the reduction of NO from reactions with NH{sub i} species. The relative importance of the four was determined by the initial conditions.

Download or read book An Experimental Study of NO Sub X Recycle in the NOXSO Flue Gas Cleanup Process written by and published by . This book was released on 1992 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: NO(subscript x) recycle is one part of the NOXSO process. In this process, 90% of the acid pollutants (NO(subscript x) and SO2) can be removed simultaneously by adsorption on the surface of a PO sorbent material. The sorbent is subsequently regenerated by heating and contacting the hot sorbent with a reducing gas followed by steam. The NO(subscript x) is removed in the heating process, and the SO2 is removed by the chemical reaction of the reducing gas and steam. The NO (subscript x) stream produced is returned to the combustion process with combustion air, which is called the NO(subscript x) recycle. The NO(subscript x) is reduced in the flame to N2, H20, and CO2. NO(subscript x) recycle will be implemented at the full-scale commercial demonstration plant at Niles. The concept of NO(subscript x) recycle has been tested previously at DOE-Pittsburgh Energy Technology Center (PETC) using a 500 lb/hr coal combustor used for the 3/4 MW tests and also using a tunnel furnace capable of being fired with a variety of fuels including gas, fuel oil, coal, and coal-water mixtures. The results were very promising and demonstrated the destruction of NO(subscript x) compounds when fed to the combustion system. The data also indicate that the extent of NO(subscript x) reduction is determined by the location of the NO(subscript x) injection and the combustor design. This current project is pilot-scale testing of NO(subscript x) destruction mechanisms and to help with the implementation at the Niles station.

Download or read book An Experimental Study of NO subscript X Recycle in the NOXSO Flue Gas Cleanup Process Quarterly Technical Progress Report April 1 June 31 1992 written by and published by . This book was released on 1992 with total page 21 pages. Available in PDF, EPUB and Kindle. Book excerpt: NO(subscript x) recycle is one part of the NOXSO process. In this process, 90% of the acid pollutants (NO(subscript x) and SO2) can be removed simultaneously by adsorption on the surface of a sorbent material. The sorbent is subsequently regenerated by heating and contacting the hot sorbent with a reducing gas followed by steam. The NO(subscript x) is removed in the heating process, and the SO2 is removed by the chemical reaction of the reducing gas and steam. The NO(subscript x) stream produced is returned to the combustion process with combustion air, which is called the NO(subscript x) recycle. The NO(subscript x) is reduced in the flame to N2, H2O, and CO2. The tests of NO injection with combustion have demonstrated very promising results. The test data showed quite consistent NO(subscript x) reduction efficiencies, which is similar to the previous test results on the pulverized coal combustor at DOE-PETC. An average of about 70 % NO. destruction efficiency was achieved for the NO injection into the primary air duct independent of injected NO flow rates and exit 02 concentrations. About 58%, 50%, and 46% average destruction efficiencies were obtained for the NO injection into the secondary air duct corresponding to the exit O2concentrations of 2%, 3%, and 4% respectively.

Download or read book Exploring the Fundamentals of Radical Assisted NO subscript X Reduction Processes of Coal Combustors Final Report written by and published by . This book was released on 1996 with total page 58 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report describes experimental studies performed at Carnegie Mellon University to study the parameters that affect the performance of plasma-assisted ammonia radical injection for NO(subscript x) control from stationary combustion sources. First, the NO(subscript x) reduction potential of hot ammonia injection was studied to determine whether the use of the plasma for radical generation was key to the high NO(subscript x) reduction potential of the plasma deNO(subscript x) process. It was found that while some of the NO(subscript x) reduction in the plasma deNO(subscript x) demonstration experiments could be attributed to the enhanced thermal breakdown of NH3 into NO(subscript x) reducing radicals, the effect of using the plasma accounted for 15--35% absolute additional NO(subscript x) reduction beyond any thermal benefit. This benefit of using the plasma increases with increased excess air and decreased flue gas temperature. With the benefit of using the plasma verified on the larger scale of a demonstration experiment, two additional experiments were performed to study the parameters that affect plasma deNO(subscript x) performance on the local level. The opposed flow experiment failed to produce significant NO(subscript x) reduction, although it did highlight some key aspects of plasma performance with ammonia injection. The reverse injection experiment successfully demonstrated the effects of NO-stream temperature, plasma power, and ammonia flow rate on plasma deNO(subscript x) performance. Finally, a preliminary study of the chemical kinetics of the plasma deNO(subscript x) system was performed. This study highlighted the importance of effective plasma temperature and the residence time of the reagent at that temperature to efficient radical generation.

Download or read book NO subscript X Reduction in Pressurized Fluidized bed Combustion written by and published by . This book was released on 1992 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: Batch combustion experiments were performed in a small bubbling fluidized-bed reactor with the objective of establishing the cause of reduced NO(subscript x) emissions from pressurized fluidized bed combustion (PFBC). All variables except for pressure were kept constant in the experiments: fuel batch size, for example, was the same in experiments performed at three pressure levels (0.2, 1 and 2 MPa). Two different types of experiments were conducted: one using air diluted with nitrogen (4.5% O2) for the purpose of determining the conversion of fuel N to NO(subscript x), and the other with NO-doped diluted air (800 ppM NO, 4.5% O2) for the purpose of determining the reduction of bulk-gas NO(subscript x) by the burning fuel. A large excess of combustion air was used in all experiments so as to keep the bulk-gas composition relatively unchanged by combustion products. Six different fuels were studied: a bituminous coal, coke prepared from the same coal, three specialty cokes (one of which contained 10 wt % N) and graphite (0%N). The straight-air combustion experiments showed that the conversion of fuel-N to NO(subscript x) dropped with increasing pressure (at constant fuel concentration in the bed). The NO-doped combustion experiments showed significantly increased NO(subscript x) reduction with increased pressure. This effect was particularly strong between 0.2 and 1 MPa, and was found to continue between 1 and 2 MPa for some of the fuels but too saturate for others. These results imply that an important phenomenon for low PFBC NO(subscript x) emission is the reaction of NO(subscript x) with reducing N-containing species at the burning fuel surfaces. A simple kinetic model involving parallel paths for the fuel-N is suggested as an interpretation of the results. The NO-doped experiments showed increased N2O formation relative to the straight-air experiments implying that N2O was a byproduct of the NO(subscript x) reduction reaction where N2 was the main product.