Zeolite membrane reactor for high-temperature isobutane dehydrogenation reaction: Experimental and modeling studies

Isobutylene has been produced by packed bed reactors (PBRs), but there is thermodynamic limitations and a critical need for efficient isobutylene production. Catalytic dehydrogenation of isobutane using a membrane reactor is a feasible solution because it helps in overcoming thermodynamic limitations as well as separates isobutylene by allowing H₂ to selectively permeate through the membrane. In this study, isobutane dehydrogenation (IBDH) in a packed-bed membrane reactors (PBMRs) in combination with a Pt/Al₂O₃ catalyst was investigated. MFI zeolite membranes were found to have good H₂/i-C₄H₁₀ selectivity which enhanced isobutane conversion at high operation temperature. The effect of the PBMR operating conditions such as weight hourly space velocity (0.8-2.7 h⁻¹), temperature (500–650 °C), and sweep gas flow rate (0-40 cm³/min) on isobutane conversion, isobutylene selectivity and isobutylene yield was studied. The highest isobutane conversion, isobutylene selectivity and isobutylene yield was 27%, 97% and 26%, respectively, from experiments. We developed a 1D plug flow reactor model for the IBDH system and isobutane conversion was evaluated at a wider range of operating conditions. Isobutane conversion of >90% was from calculation obtained at practically meaningful operating conditions.