Chemical Engineering Science, Vol.54, No.20, 4437-4448, 1999
Cyclic operation of the oxidative dehydrogenation of propane
The cyclic operation of the oxidative dehydrogenation of propane over a V-Mg-O catalyst by the alternate feeding of propane and oxygen gas mixtures was investigated. Generally, the response of the reaction products following a step-change in composition determined the cyclic conditions that resulted in an improved yield of propene. By alternating propane and oxygen with a 1 : 1 cycle split, time-average propene yields higher than steady state could be obtained. The optimal cycle period was about 60 s. This same period provided high propane conversion, as well as high propene selectivity. The cycle split could be varied by shortening the oxygen-feed half of the cycle with little effect on the time-average results. The oxygen half-cycle needed only to be long enough to reoxidize the catalyst. The propane feed scheme was varied by feeding increasing amounts of propane in the oxygen half-cycle. The change in feed scheme caused an increase in the time-average propane conversion that resulted in some further improvement in the propene yield despite some loss in propene selectivity.