| Summary: | 碩士 === 國立成功大學 === 航空太空工程學系碩博士班 === 96 === In view of the increasing intensive attention of the biomass energy and low heating value fuels as applied in miniature gas turbines for electricity generation, in this thesis we propose a novel concept of catalytic mesh and screen mesh for use in the miniature gas turbine combustors to stabilize the low-BTU syngas combustion. Catalyst provides the outstanding features of stable reactions for low-BTU, low temperature and ultra lean fuels, which are suitable for conditions of gas turbine combustion burning syngases. In initial tests with honeycomb catalysts, we found that in the operation the honeycomb catalyst tends to be over-heated on the catalyst surface and causing sintering on the catalyst bed structure. In addition, the output temperature tends to be too low to sustain the gas phase reaction downstream. Therefore, honeycomb catalysts will be suitable for smaller operation range and should be operated with more precise operation conditions.
The novel concept for catalytic combustion of low-BTU syn-gas in a gas turbine combustor is to first catalytically convert a portion of the fuel, mainly highly active hydrogen, to raise the temperature of the fuel-air mixture stream so that gas phase reaction of the high speed mixture leaving the catalyst bed can be stabilized downstream or by mesh flame holder. The outstanding feature of this concept is to avoid causing over-heating and sintering of the catalyst bed as well as to sustain and stabilize a low-temperature flame downstream to have complete combustion of the low-BTU syn-gas.
The combustion and stabilization characteristics of screen mesh flame holders in different mixture velocities and different components of fuels are investigated by measurinf the catalyst temperature, exiting temperature, and exhaust gas analysis. Gas phase reaction will be enhanced by screen mesh flame holder when increasing mesh per inch, distance from catalytic mesh, and number of the screen meshes in higher velocity. The feasibility and the operational characteristics of the catalytic mesh-stabilized combustor for miniature gas turbine burning syngas are investigated and proven in this study.
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