Evaluation of the Performance of a High Temperature Adsorber In a Solid Oxide Fuel Cell System

Solid Oxide Fuel Cells (SOFC) are highly efficient electricity-generating devices that can run on a variety of fuels, including hydrogen, hydrocarbons, methanol, etc. A variety of technologies can be used to generate a hydrogen-rich product gas, including fossil fuel combustion, gasification of coal, etc. However, heavy liquid fuels and coal contain organosulfur compounds that can react with the nickel-based anode electrocatalyst causing irreversible fuel cell power losses. Even low sulfur fuels will produce tens of ppm H₂S at the reformer exit, while the levels of H₂S in gasifier-exit gases may be over 1000 ppm. A high temperature adsorption separation process can be used to remove sulfur from the H₂ feed. The performance of a lanthanum based H₂S adsorbent in a pressure swing adsorption unit was studied using gPROMS, commercial computer simulation software. The effects of the feed pressure and concentration, mass transfer resistance, cycle time and regeneration conditions on the system performance were analyzed. The model predictions will allow designing an adsorption unit for the removal of H₂S from the anode feed stream and protect the solid oxide fuel cell.