Sorbents for Removing Sulfur-Bearing Odorants from Natural Gas and LPG

72882-Chemical odorants made with sulfur-containing compounds are added to propane and natural gas supplies to facilitate leak detection. However, in the fuel processing systems of fuel cells, these compounds can contaminate the anode catalysts of the fuel cell itself, thereby degrading power generation performance. This project will develop a low-cost, high-capacity, sorbent that can reduce the concentration of organic sulfur species to less than parts per billion levels in natural gas and LPG. Phase I developed a low cost, high capacity sorbent that can remove sulfur-bearing odorants from natural gas and LPG. The technical and economic feasibility of using this sorbent, which dramatically reduces the cost of odorant removal, was demonstrated. A preliminary engineering analysis showed that the size of the desulfurization system, designed to last the entire 10-year life of a 5 kW fuel cell, could be reduced to 19 L. In Phase II, the sorbent will be scaled-up for production using commercial manufacturing techniques. The desulfurization sorbent will be integrated with a fuel cell system (with fuel cell stacks, fuel processor and all auxiliary items) in a full-scale field test. A detailed engineering analysis will be conducted to assess the impact of the sorbent on the efficiency, size, and cost of the overall fuel cell system. Commercial Applications and Other Benefits as described by awardee: Fuel cells have great potential as decentralized energy power systems. A cost-effective sorbent that removes sulfur impurities should find immediate use in the fuel cell market; the residential U.S. market alone could be as much as 1,093,000 MW. The highly selective, low-cost sorbents with a high sulfur removal capacity also should benefit catalytic chemical manufacturing processes (e.g., hydrogen production, methanol and ammonia synthesis) that use natural gas as a feedstock.