Abstract:

Catalyst is one of the most important factors to determine the cost and life of reforming system in natural gas steam reforming process. Application of low-cost Ni catalyst is limited in the area of reformer with a small & medium scale for distributed power generation，because of its characteristics of sintering and carbon formation at a relatively high reforming temperature. In order to allow Ni catalyst work at a mild temperature with little sintering and carbon formation，the influence of composition of reformer inlet gas on reforming temperature at a certain space velocity and conversion of feed CH₄ was studied. At the same time，a method of changing inlet gas composition by introducing circulating gas into the feed gas was also discussed. Experimental results showed that the working temperature of Ni catalyst with introducing circulating gas into the feed gas decreased greatly comparing to that without introducing circulating gas at the same space velocity and conversion of feed CH₄.According to this study，a new steam reforming process applicable to distributed fuel cell power generation system with a small & medium scale was proposed，in which the fuel cell anode outlet gas was separated into two parts，one part was circulated and introduced into the reformer after mixing with the feed gas，to greatly lower the working temperature of natural gas steam reforming.