Steam Reforming of n-Butane in Membrane Reactor with Industrial Nickel Catalyst and Foil Made of Pd-Ru Alloy

Abstract

Steam reforming of n-butane has been studied in a membrane reactor at temperatures of 673-823 K, feed hourly space velocities of 1800 and 3600 h-1 , and steam/butane ratios of 3, 5 and 7. Under selected conditions, the steam conversion is accompanied by the formation of carbon deposits, whose yield decreases with increasing steam excess. However, with an increase in steam excess, its negative effect on H 2 recovery through the membrane increases. Comparative experiments with the "non-membrane" reaction at a constant steam/butane ratio equal to 5 have shown that butane conversion to the target products increases in the membrane reactor and the rate of carbon deposits formation decreases. When replacing the sweep gas by the vacuum conditions in the permeate side, there is a further decrease in the rate of carbon deposits formation and an increase in the butane conversion in the main reaction. With an increase in feed hourly space velocity from 1800 to 3600 h-1 , the rate of carbon deposits formation and its dependence on temperature increase. At an hourly space velocity of 1800 h-1 , the rate of formation of carbon deposits is two to three times lower and varies slightly with temperature. Under these conditions, the butane conversion is close to 100%; about 80% of H 2 formed is recovered from the reaction mixture, and at vacuum conditions in the permeate side, the H 2 recovery is 95%.