Numerical Analysis of Methanol Steam Reforming Reactor for kW-Scale Fuel Cells

As an efficient energy conversion device, fuel cells are increasingly being applied. Fuel supply is the core link to ensure the normal operation of fuel cells. In this paper, a methanol steam reforming reactor was designed to supply fuels for kW-scale fuel cells. The effects of steam to carbon ratio (S/C), combustion temperature and liquid speed velocity (LHSV) on reforming performance were studied by CFD method. The results shown that the S/C and combustion temperature are the main factors affecting the reforming performance. As the S/C and combustion temperature increases, the methanol conversion rate increases, reaching a maximum of 99.85%. But using the methanol aqueous solution with high S/C for reforming, the H2O content in the hydrogen rich gas is high, which reducing the power generation performance of the fuel cell. 1.2 is the best S/C for reforming to get the greatest reforming performance by experiments and simulations. Due to the structure limit, excessively high combustion temperature leads to the local high temperature areas in the reforming chamber that caused the methanation. Reducing the LHSV can increase the methanol conversion rate. Supplying fuel for 1kW SOFC, the LHSV of the reactor is 1.3 h−1. It is feasible to expand the reactor power through proportional scaling. After increasing the heat supply, the methanol conversion rates of both 50kW and 100kW reactors can reach over 96%.