at temperatures higher than 400 0F (200 0C)， but decomposes to the meta1 at temperatures between 1436 0F (780 0C) and 1690 0F (920 0C)， depending on the pressure. So when the cata1yst temperature reaches about 1472 0F (800 0C) the cata1ytic activity wi11 sudden1y fa11 off due to the formation ofthe 1ess active pa11adium meta1， preventing any further rise in temperature. The cata1yst essentia11y acts as a kind of chemica1 thermostat that contro1s its own temperature.
Catalytic Combustor Design
Testing at fu11 sca1e has been done in a cata1ytic combustor system deve1-oped by GE for its MS9001E gas turbine. The MS9001E combustor operates with a fu11 1oad firing temperature of 2020 0F (1105 0C) and a combustor exit temperature of about 2170 0F (1190 0C). The key components of the test stand at the GE Power Generation Engineering Laboratories in Schenec-tady， New.ork， are shown in Figure 10-28.
Figure 10-2.. Schematic of a full scale catalytic combustor Courtesy GE .ower Systems and Catalytica Combustion Systems Inc
There are four major subassemb1ies in the overa11 combustion system: thepreburner， the main fue1injector， the cata1ytic reactor.
.reburner. The preburner carries the machine 1oad at operating points where the conditions in the cata1ytic reactor are outside of the cata1ystoperating window. Mostoften， these are the 1ow 1oad points where the fue1 required for turbine operation is insufficient for the cata1yst to generate the necessary minimum exit gas temperature. As the turbine 1oad isincreased， progressive1y more fue1 is directed through the main injector and progressive1y 1ess goes tothe preburner. .1timate1y， the preburner receives on1y enough fue1 to maintain the cata1yst above its minimum in1et temperature.
Main .uel in.ector. This unit is designed to de1iver a fue1-air mixture to the cata1yst that is uniform incomposition， temperature， and ve1ocity. A mu1ti-venturi tube (MVT) fue1 injection system was deve1oped by GE specifica11y for this purpose. lt consists of 93 individua1 venturi tubesarrayed across the f1owpath， with four fue1 injection orifices at the throat of each venturi.
Catalytic reactor. The ro1e of the cata1yst was described ear1ier; it must burn enough of the incoming fue1 to generate an out1et gas temperature high enough to initiate rapid homogeneous combustion just past the cata1yst exit.
The cata1ytic combustor has great potentia1 in the app1ication of gas turbines in new combined cyc1e power p1ants as the NOx emissions in high attainment areas wi11 have to be be1ow 2 ppm.
.ibliography
Ba11a1，D.R.， andLefebvre，A.H.， ..A Proposed Method for Ca1cu1ating Fi1mCoo1ed Wa11 Temperatures in Gas Turbine CombustorChambers，'' ASMEPaper#72-WAjHT-24， 1972.
C1arke，J.S.， andLardge，H.E.， ..The Performance and Re1iabi1ity of Aero-GasTurbine CombustionChambers，'' ASME58-GTO-13， 1958.
Da11aBetta， Ra1phA.，Nicko1as，S.G.，Weak1ey，C.K.，Lundberg，K.，Caron，
T.J.，Chamber1ain，J.， andGreeb，K.， ..Fie1d Test of a 1.5 MW lndustria1Gas Turbine with a Low Emissions Cata1ytic CombustionSystem，'' ASME 99-GT-295.
Dutta，P.，Cowe11，L.H.，.ee，D.K.， and Da11aBetta，R.A.， ..Design and Eva1ua-tion of a Sing1e-Can Fu11 Sca1e Cata1ytic Combustion System for .1tra-LowEmissions lndustria1 GasTurbines，'' ASME 97-GT-292.
Faires，V.M.， andSimmang，C.M.，Ther的odynα的ics， 6thed.， The Macmi11anCo.， New.ork，1978， pp. 345-347.
Grahman，J.，Jones，R.E.，Mayek，C.J.， andNiedzwicki，R.W.， Aircrαft Propul-sion， Chapter 4. NASA SP-259.
Greenwood，S.A.， ..Low Emission Combustion Techno1ogy for Stationary Gas TurbineEngines，'' Proceedings of the 29thTurbomachinerySymposium， September 2000.
中國航空網 www.k6050.com
航空翻譯 www.aviation.cn
本文鏈接地址：燃氣渦輪工程手冊 Gas Turbine Engineering Handbook 2(53)
