Highly efficient and stable hydrogen permeable membrane reactor for propane dehydrogenation

Abstract

The synthesis of SAPO-34 hollow fiber membranes employs the ball-milling assistant method to enhance membrane yield and quality. These membranes are then combined with CrOx/Al2O3 catalyst to create a packed bed membrane reactor (PBMR) for propane dehydrogenation (PDH). The study investigates the impact of operating temperatures, weight hourly space velocities (WHSV), and sweep gas flow rates on the SAPO-34 zeolite membrane reactor's performance, comparing it to a traditional packed bed reactor (PBR). The removal of hydrogen from the reaction side significantly improves propane conversion, surpassing thermodynamic equilibrium. In PBMR, propylene selectivity slightly exceeds that in PBR, influenced by side reactions like hydrogenolysis and cracking after hydrogen removal. Furthermore, the SAPO-34 zeolite membrane reactor undergoes a prolonged stability test with frequent regeneration using pure propane as feedstock to simulate industrial conditions. It exhibits consistent performance over 120 regeneration cycles within 240 h, maintaining similar H2 permeability and H2/C3H8 selectivity as the fresh membrane post long-term testing.