Analysis of Transient Behavior of Fuel Reformer to Fuel Supply Variation in Solid Oxide Fuel Cell Systems with Anode Off-Gas Recycle

Abstract

In the case of increasing fuel supply to solid oxide fuel cell (SOFC) systems, mass transport delay generally occurs in reformers and SOFCs. Therefore, heat used for fuel reforming becomes larger than heat supplied to reformers, and reformer heat tends to be absorbed. In this paper, transient behavior of reformers in SOFC systems with anode off-gas recycle, in the case of increasing fuel supply, is analyzed by numerical simulation. As a result, it is suggested that reformer temperature decreases from several to several tens of K, when heat is absorbed from the reformer, which is small scale, lightweight and has low heat capacity, for several seconds. In addition, methane flow rate outputted from the reformer increases, and carbon deposition occurs, depending on conditions. This paper will present details of these results and discuss methods to prevent carbon deposition and increase of CH4 output from the reformer.