7 - Fuel processing systems

Abstract

This chapter of this book deals with fuel processing systems for application in fuel cell technology. There are various types of fuel cells that are under research stage or are already commercialized. A fuel cell system, in addition to the stack, contains a number of other components called balance of plant (BoP). A fuel processing unit is probably one of the most important BoP that is integral to the stable operation of the fuel cell. The purpose of the fuel processing system is to produce fuel from primary sources that can be electrochemically oxidized in a fuel cell without causing appreciable performance loss of the cell. The fuel quality requirements are different for different fuel cell types as some fuel cell types are capable of tolerating impurities to a higher level without undergoing appreciable performance degradation. However, it is very important to understand the operating limits of a particular fuel cell type with respect to the concentration of impurities it can tolerate so that appropriate fuel processing units can be designed. The more stringent the fuel quality requirements are, the more expensive the fuel processing becomes. The discussion in this chapter is mostly focused on fuel quality requirements and fuel processing of common fuels for polymer electrolyte membrane fuel cell (PEMFC) and Solid Oxide Fuel Cells (SOFCs) as they attract significant attention from the fuel cell community.