Showing papers on "Afterburner published in 2001"

Integrated module for solid oxide fuel cell systems

Abstract: An integrated module includes an afterburner, heat exchanger and fuel processor. The module is thermally integrated solid oxide fuel cell.

Fuel cell battery for liquid fuels

Abstract: The fuel cell battery ( 1 ) for liquid fuels has the following components: a cell stack ( 2 ) which is arranged along an axis ( 2 a ) and within a periphery ( 2 b ); a distributor passage ( 21 ) on the stack axis ( 2 a ) via which a reformed fuel gas can be fed in into cells ( 20 ) of the stack ( 2 ); afterburner chambers ( 22 ) at the stack periphery ( 2 b ); furthermore an auxiliary burner ( 3 ) for a start-up operation. A reaction device ( 3 ) is in connection with the cell stack and is provided for the treatment of the liquid fuel by reforming with partial oxidation to form a fuel gas which contains CO and H 2 . A heat exchanger system ( 4 ) is integrated into the reaction device, by means of which, in a current delivering operation of the battery ( 1 )—using hot exhaust gas from the afterburning chambers—the liquid fuel can be vaporized and a gaseous oxygen carrier can be heated up. Via an infeed point ( 6 ) which is part of the heat exchanger system, vaporized fuel can be brought into contact with a heated up oxygen carrier for forming the reformed fuel gas. This fuel gas can be fed in from the reaction device into the distributor passage of the cell stack.

Towards replacement of turbofan engines afterburners with pulse detonation devices. I

Abstract: The feasibility of placing pulse detonation devices in the rear of a turbofan engine as a new pulse detonation afterburner concept (PDAC) has been assessed in the present study for a given sea level static power condition and an engine size. A turbofan engine with a pulse detonation afterburner was studied and its performance was obtained. The thrust, SFC and specific thrust of a turbofan engine with a conventional afterburner and with the new pulse detonation afterburner concept were calculated and compared. The turbofan engine performance with the new pulse detonation afterburner concept was obtained using multidimensional CFD and cycle analysis as a function of the engine core flow fraction passing through the pulse detonation device. The results showed that the engine performance, in terms of total thrust, SFC and specific thrust, is improved as the engine core flow fraction allowed in the pulse detonation chamber is increased. However, the predicted total thrust, SFC and specific thrust of the turbofan engine with a pulse detonation afterburner fall short than those of a turbofan engine with a conventional deflagration combustion afterburner. The reduction in the turbofan engine performance with a pulse detonation afterburner was attributed to the reduction in initial mixture fuel-air ratio as the core flow products fraction inside the detonation chamber is increased and the neglect of the pulse detonation exhaust stream momentum in the thrust analysis. An analysis, which would address the pulse detonation exhaust stream momentum and the engine nozzle performance, is therefore warranted. 1 Member AIAA Copyright © 2001 by the authors. Published by the American Institute of Aeronautics and Astronautics, Inc., with permission. NOMENCLATURE A = constant cross-sectional area A/B = afterburner Favg = average thrust FPR = fan pressure ratio F = cycle frequency Mmass = mass averaged Mach number OPR = overall pressure ratio P(t) = unsteady pressure at the tube wall Pdrag = pressure acting on left side of thrust wall Pmass = niass averaged initial mixture pressure PPH = Ibm/hr SFC = specific fuel consumption Tcycie = cycle time Tdetonation= detonation time Tfin = filling time = initiation time = mass averaged initial mixture temperature = purging time t = time yi = mixture mass fraction = mixture equivalence ratio

Zero Emission Power Plants Using Solid Oxide Fuel Cells and Oxygen Transport Membranes

Abstract: Siemens Westinghouse Power Corp. (SWPC) is engaged in the development of Solid Oxide Fuel Cell stationary power systems. SWPC has combined DOE Developmental funds with commercial customer funding to establish a record of successful SOFC field demonstration power systems of increasing size. SWPC will soon deploy the first unit of a newly developed 250 kWe Combined Heat Power System. It will generate electrical power at greater than 45% electrical efficiency. The SWPC SOFC power systems are equipped to operate on lower number hydrocarbon fuels such as pipeline natural gas, which is desulfurized within the SOFC power system. Because the system operates with a relatively high electrical efficiency, the CO2 emissions, {approx}1.0 lb CO2/ kW-hr, are low. Within the SOFC module the desulfurized fuel is utilized electrochemically and oxidized below the temperature for NOx generation. Therefore the NOx and SOx emissions for the SOFC power generation system are near negligible. The byproducts of the power generation from hydrocarbon fuels that are released into the environment are CO2 and water vapor. This forward looking DOE sponsored Vision 21 program is supporting the development of methods to capture and sequester the CO2, resulting in a Zero Emission power generation system. To accomplish this, SWPC is developing a SOFC module design, to be demonstrated in operating hardware, that will maintain separation of the fuel cell anode gas, consisting of H2, CO, H2O and CO2, from the vitiated air. That anode gas, the depleted fuel stream, containing less than 18% (H2 + CO), will be directed to an Oxygen Transport Membrane (OTM) Afterburner that is being developed by Praxair, Inc.. The OTM is supplied air and the depleted fuel. The OTM will selectively transport oxygen across the membrane to oxidize the remaining H2 and CO. The water vapor is then condensed from the totally 1.5.DOC oxidized fuel stream exiting the afterburner, leaving only the CO2 in gaseous form. That CO2 can then be compressed and sequestered, resulting in a Zero Emission power generation system operating on hydrocarbon fuel that adds only water vapor to the environment. Praxair has been developing oxygen separation systems based on dense walled, mixed electronic, oxygen ion conducting ceramics for a number of years. The oxygen separation membranes find applications in syngas production, high purity oxygen production and gas purification. In the SOFC afterburner application the chemical potential difference between the high temperature SOFC depleted fuel gas and the supplied air provides the driving force for oxygen transport. This permeated oxygen subsequently combusts the residual fuel in the SOFC exhaust. A number of experiments have been carried out in which simulated SOFC depleted fuel gas compositions and air have been supplied to either side of single OTM tubes in laboratory-scale reactors. The ceramic tubes are sealed into high temperature metallic housings which precludes mixing of the simulated SOFC depleted fuel and air streams. In early tests, although complete oxidation of the residual CO and H2 in the simulated SOFC depleted fuel was achieved, membrane performance degraded over time. The source of degradation was found to be contaminants in the simulated SOFC depleted fuel stream. Following removal of the contaminants, stable membrane performance has subsequently been demonstrated. In an ongoing test, the dried afterburner exhaust composition has been found to be stable at 99.2% CO2, 0.4% N2 and 0.6%O2 after 350 hours online. Discussion of these results is presented. A test of a longer, commercial demonstration size tube was performed in the SWPC test facility. A similar contamination of the simulated SOFC depleted fuel stream occurred and the performance degraded over time. A second test is being prepared. Siemens Westinghouse and Praxair are collaborating on the preliminary design of an OTM equipped Afterburner demonstration unit. The intent is to test the afterburner in conjunction with a reduced size SOFC test module that has the anode gas separation features incorporated into the hardware.

Research on Combustion Performance of the Edge Blowing Mixture Curtain Flameholder

Abstract: On the basis of elementary research,the geometry structure of the edge blowing mixture curtain (EBMC) flameholder was improved and the experimental study on the combustion performance of the EBMC flameholder was carried out in 2D afterburning test rig.The flame stability,the influence of jet velocity and fuel supply at the trail edge on the combustion performance and the performance difference between fuel supply from the frontal injector and jet curtain were analyzed.At the same time,V-gutter flameholder was used to compare with the new type flameholder.The results show that the new type flameholder is a controllable flameholder,that can work stably with higher efficiency and lower pressure loss.It is expected to be used in future aero-engine,especially its by-pass afterburner.