Water Vapor Effects on Fuel Cell Desulfurizer Performance: A Decade of Field Experience

Operation of Siemens solid oxide fuel cell (SOFC) units using natural gas fuel has required sulfur selective sorbents for fuel desulfurization. Experience with physical sorbents has shown varying sulfur capacity during field operation. This has been puzzling and produced great uncertainty for selection of sorbents. This mystery of changing sorbent sulfur capacity has been partially solved. Measurements of considerably variable and unexpectedly high water vapor content in pipeline natural gas supplies appears to be a major contributor to competition for sulfur adsorption sites and results in variable sorbent performance. A summary (Table 1) shows operating lifetimes of several sorbents to remove sulfur from pipeline natural gas at several field sites, spanning about one decade of experience.