The Dehydrogenation of Propane on Platinum-Tin Glass-Fiber Woven Catalysts

The reaction of propane dehydrogenation on platinum-tin catalysts supported onto different woven carriers (an aluminoborosilicate and two silica materials) was studied. It was found that the catalyst was rapidly deactivated by carbon deposits formed, and the rate of this reaction increased with the specific surface area of the glass-fiber woven material and the Pt content. It was established that the Pt: Sn ratio in surface platinum particles was about 6, and it increased to 39 after the reaction; this fact is indicative of a Sn loss, which led to an increase in the conversion of feed into carbon deposits that deactivated the catalyst. A mixture of propane and 5-10 vol % H-2 should be used for the stabilization of the catalytic system; in this case, the negative effect of hydrogen on the yield of propylene was minimal. On the catalyst supported onto a silica carrier under optimum conditions (550 degrees C; propane space velocity, 480 h(-1)), which correspond to minimum selectivity for the formation of carbon deposits, the yield of propylene was similar to 18%. The test glass-fiber woven catalyst was inferior to granulated platinum-tin catalysts in terms of catalytic activity; therefore, its use in the reaction of propane dehydrogenation is inexpedient.