Gas Clean-Up for Fuel Cell Systems - Requirements & Technologies

Abstract

In this chapter the impact of prominent fuel gas contaminants on high and low temperature fuel cells is discussed, together with maximum tolerable contaminant levels. Contaminant loads strongly depend on the type of fuel, its origin, and processing steps. The most notorious contaminants identified are sulfur compounds, which are present in almost all available fuel gas sources. Furthermore, they exhibit the most stringent requirements with regard to cleaning process parameters, such as temperature. Other important contaminants are tarry substances and other hydrocarbons, and - for low temperature fuel cells - carbon monoxide. Subsequently, suitable technologies for clean-up of the most important contaminants from fuel gases are described. Here, the focus is on high temperature gas cleaning options, since compared to state of the art low temperature gas cleaning they allow higher overall system efficiencies.