The Effects of Operating Parameters on Hydrogen Production Rate in a Cylindrical Steam-Methane Reformer with Natural Gas Combustor and Cooling Water Jacket

A cylindrical fuel processor with a central combustor has large temperature gradients between combustor and steam reforming reactor (SMR). Because of negative effects of the non-uniform temperature distributions on the reforming efficiency and the durability of SMR catalysts, thermo-chemical balance over the entire flow-field should be carefully investigated. In this study, numerical analysis was performed to figure out thermo-chemical characteristics of the SMR under various operating conditions. The cylindrical fuel processor consists of combustion and reforming parts, respectively. A combustor supplies thermal energy for endothermic reaction of steam-methane reforming. The packed-bed reactors produce hydrogen -rich gas by steam-methane reforming and water gas shift reactions. To get more accurate results of heat transfer phenomena, radiation and buoyancy effects were applied. The two-dimensional reformer model was developed and validated against experimental data. Using the developed model, the effects of operating parameters such as S/C ratio, GHSV and cooling heat flux were numerically studied. When steam to carbon ratio increases, the conversion of methane increase. When increasing GHSV, the fuel conversion decreases. The results of this study will be utilized as reference data in future studies of the fuel processing system for the design and optimization.