Numerical and Experimental Investigation on the Performance of Lean Burn Catalytic Combustion for Gas Turbine Application

This manuscript presents our numerical and experimental results regarding the performance characteristics of lean bum catalytic combustion for gas turbine application. The reactant transport was assumed to be controlled by both bulk diffusion as well as surface kinetics, implemented by means of an approximate reaction rate equation and empirical coefficients to incorporate reaction mechanism. Experimental and numerical results were compared to examine the effects of methane mole fraction, inlet temperature, operating pressure, velocity and hydrogen spe- cies on combustion intensity. The results indicate that inlet temperature is the most significant parameter that im- pacts operation of the catalytic combustor and the most effective methods for improving the methane conversion are increasing the inlet temperature and increasing the methane mole fraction. Simulations from ID heterogene- ous plug flow model can capture the trend of catalytic combustion and describe the behavior of the catalytic mo- nolith in detail. The addition of hydrogen will provide heat release by the exothermie combustion reaction so that the reactants reach a temperature at which methane oxidation can light-off.

Part-load Performance Characteristics of a Lean Burn Catalytic Combustion Gas Turbine System

The purpose of this study is to compare the part-load performance of a lean burn catalytic combustion gas turbine (LBCCGT) system in three different control modes: varying fuel, bleeding off the fuel mixture flow after the compressor and varying rotational speed. The conversions of methane species for chemical process are considered. A 1D heterogeneous plug flow model was utilized to analyze the system performance. The actual turbomachinery components were designed and predicted performance maps were applied to system performance research. The part-load characteristics under three control strategies were numerically investigated. The main results show that: the combustor inlet temperature is a significant factor that can significantly affect the part-load characteristics of the LBCCGT system; the rotational speed control mode can provide the best performance characteristics for part-load operations; the operation range of the bleed off mode is narrower than that of the speed control mode and wider than that of the fuel only mode; with reduced power, methane does not achieve full conversion over the reactor at the fuel only control mode, which will not warrant stable operation of the turbine system; the thermal efficiency of the LBCCGT system at fuel only control strategy is higher than that at bleed off control strategy within the operation range.