Sulfur Tolerance of Carbide Catalysts Under Hydrocarbon Reforming Conditions

摘要

A three year project to determine the feasibility of molybdenum carbide catalysts for the reforming of hydrocarbon fuels has been completed. As a result of this project, conditions for maintaining the stability of these catalysts under both dry and steam reforming methane have been determined. In particular it has been found that these catalyst can be kept stable by either operating at high temperatures, high pressures or by recycling CO and/or H2. These conditions are all related to lowering gas-solid mass transfer rate has also been determined that tedious TPR catalyst synthesis techniques are not necessary to achieve either catalyst activity or stability. Because of these findings, it has also been possible to operate these catalysts at space velocities in excess of 30,000 hr-1 an to therefore measure reaction kinetics for the first time. Finally, the sulfur tolerance of these catalysts has been studied by exposing them to a model sulfur compound (dimethylsulfide) during steam and dry reforming at sulfur concentrations as high as 500 ppmv. concluded that sulfur reversibly chemisorbs on the catalyst surface, causing reduced but stable activity, and complete activity recov can be obtained by simply removing sulfur from the feed.