Propane to light olefins by one-pot cascade and series reactions

Abstract

Propane is selectively converted to propylene via propane dehydrogenation (PDH) process for an on-purpose propylene usage. Due to regional market demands, olefin interconversion for propylene-to-ethylene (PTE) is required to control the supply-demand of light olefins. Our concern centers on combining the PDH and PTE reactions to achieve a simple catalytic process for selective production of light olefins from propane. Herein, converting propane to light olefins is investigated via cascade and series PDH-PTE reactions over highly selective two catalysts. From the catalytic results, selectively produced propylene over a PDH catalyst (Cr2O3/Al2O3) from propane was readily converted to other light olefins over a PTE catalyst (modified ZSM-5). The modified ZSM-5 as the PTE catalysts was further studied in the both cascade and series reactions with different reaction conditions in order to find an optimum reaction condition for high olefin yield and selectivity with low methane selectivity as well as to investigate the influence of process parameters on the catalytic activity. The AHFS treated ZSM-5 (AHFS-ZSM-5) as the PTE catalyst in PDH-PTE series reaction exhibited a superior light olefin yield (50.7 wt%) and olefin selectivities up to 76.7 wt% (26.9 wt% ethylene, 38.0 wt% propylene, and 11.8 wt% butenes) with low methane selectivity (4.27 wt%) at 550 °C, WHSV 7 h−1, and propylene partial pressure in the PDH model feed 0.025 MPa.