CFD Modeling of Exhaust Heat Recovery Using Methane Steam Reforming in Steam Reformer of Chemically Recuperated Gas Turbine

To ensure the maximum exhaust heat recovery in different working conditions in Steam Reformer (SR) of Chemically Recuperated Gas Turbine (CRGT), this paper studied the influence of steam to carbon ratio (S/C), reformer inlet temperature, and total mass flow rate in catalytic bed on the reactant conversion, product selectivity, heat recovery rate and fuel calorific value increasing rate by numerical simulation. It’s noted that the working parameters are given based on the chemically recuperated test bench. The model considered catalytic bed as porous media region using Fluent, including fluid flow, heat transfer and chemical reactions on reformer. Chemical reaction rates were implemented in C language and were used as a User-Defined Function (UDF) in Fluent. As a result, in single stage SR, namely the insulating tubular reactor, the reactant temperature and concentration continually decline along the axial position, especially in the inlet decline significantly. The higher inlet temperature is better for reactant conversion and heat recovery rate. When steam mass flow is fixed, the higher S/C is, the lower heat recovery rate is. In a certain total mass flow rate, the length L of reaction zone has no significant influence on the reactant conversion, product selectivity, heat recovery rate and the fuel calorific value increasing rate. When the length L is fixed, as total mass flow rate increases, methane conversion and fuel calorific value increasing rate reduce, while, heat recovery rate increases. The proposed research confirms optimal fuel mass flow and S/C in reformer under certain working conditions, and provides the basis for operation and regulation of Chemically Recuperated Test Bench.