Butane Oxidation To Maleic Anhydride Fixed-bed Reactor Person Non-steady State Operating Characteristics

Currently, the selective oxidation of n-butane to maleic anhydride (MA) over vanadium phosphorus oxide catalysts (VPO) is the only industrial process involving the selective oxidation of a light alkane. Unsteady state operation offers a new means of controlling total oxidation by segregating the hydrocarbon feedstock from oxygen. That is, splitting up of the overall reaction in spatial or temporal to two steps, hydrocarbon selective oxidation and re-oxidation of catalyst reduced, and matching each step with suitable reaction condition.In order to seek after a more effective vanadium phosphorus oxide catalyst for unsteady state operation, we evaluated three new VPO catalysts added with some promoters in a micro-reactor, the result shows that these catalysts are not worthy of being lucubrated into unsteady state operation.To investigate forced unsteady state operation performances of butane selective oxidation to MA , a single-tube wall-cooled fixed-bed reactor filled with 30g cylindrical catalyst was setup. Feed composition modulation enhanced selectivity of maleic anhydride but the conversion of butane and yield of maleic anhydride dropped. a new modulation scheme of both composition and temperature was also examined. With a 0.4 cycle split and period of 8 minutes, re-oxidation at 530 and selective oxidation at 405, the yield to maleic anhydride by both composition and temperature modulation was improved 11.4% than that operated in steady state at the same time-average flow of n-butane. It indicated that higher re-oxidation temperature was effective to improve reactor performance.