Performance evaluation of natural gas based steam reformer for PEMFC

This paper presents performance evaluation of natural gas based steam reformer with special attention on the operating conditions of internal combustor. In steam reformer in which strong endothermic process is involved, appropriate control of heat source is highly important that enables the efficient hydrogen production. In this study, experimental measuring device was setup to evaluate the performance of steam reformer for 5 kW PEMFC. The objective of the study is to investigate the dependence of the performance such as hydrogen reforming efficiency on the operation conditions such as inflowing mixed gas ratio and heat transfer through main reforming reactor and auxiliary combustor. Experimental results showed that the hydrogen conversion rate can be improved through the temperature distribution control based on (1) main reactor inlet gases ratio such as steam to carbon ratio (SCR) and (2) air-fuel ratio at the auxiliary combustor. With the increment of the amount of fuel in the combustor, the overall internal temperature could increase generally, but the thermal efficiency does not always increase. The study shows that the thermal efficiency and the fuel conversion rate of steam reformer could be improved by the effective heat transfer design and optimized parameter setup such as appropriate inlet gas mixed ratios.