入口气体组成对天然气重整工作温度的影响

重整催化剂是影响重整制氢系统造价和寿命的重要因素。由于在所需重整温度下容易烧结积炭，廉价的Ni系催化剂在分布式中小型重整反应器中的应用受到了限制。为了使Ni系催化剂在不易发生烧结积炭的温度下工作，分析了在一定原料CH4空速和转化率下入口气体组成对重整工作温度的影响，并探讨了在原料气中导入循环气来改变重整入口气体组成的方法。结果表明：Ni系催化剂在导入一定组成和流量比的循环气与不导入循环气时相比，一定原料CH4空速和转化率下的重整工作温度大幅降低。据此，提出了一种用于燃料电池电站氢源系统的重整制氢工艺流程，其特征是将部分燃料电池阳极出口气作为循环气与原料气混合后导入重整反应器，使天然气重整工作温度大幅降低。

Effect of inlet gas composition on working temperature of natural gas steam reforming

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.