Synthesis of C2+ hydrocarbons by CO2 hydrogenation over the composite catalyst of Cu–Zn–Al oxide and HB zeolite using two-stage reactor system under low pressure

Abstract

The combination of methanol synthesis and methanol-to-gasoline (MTG) reaction is a beneficial process to produce particular C 2+ hydrocarbons from CO 2 and H 2 , because MTG reaction can produce C 2+ hydrocarbons selectively without the formation of methane. However, the composite catalysts consisting of methanol synthesis catalyst and zeolite previously reported have produced C 2+ hydrocarbons in poor yields especially under low pressure conditions. This paper reports the high yield production of C 2+ hydrocarbons by CO 2 hydrogenation using a two-stage reaction system consisting of a Cu-Zn-Al oxide catalyst in the first reactor and a composite catalyst of the Cu-Zn-Al oxide and HB (zeolite beta) in the second reactor. The key points of this system are reversed water-gas-shift (RWGS) reaction in the first reactor and the following H 2 O removal before the second reactor. The gas mixture supplied to the second reactor containing much amount of CO and little H 2 O enhanced the methanol synthesis and suppressed the methanol decomposition to CO over the Cu-Zn-Al oxide catalyst in the composite catalyst, promoting the MTG reaction to produce C 2+ hydrocarbons over HB zeolite. The highest yield of C 2+ hydrocarbons reached to approximately 15 C-mol% under 0.98 MPa.

A short review of recent advances in CO2hydrogenation to hydrocarbons over heterogeneous catalysts

“…The preservation of the strong acid sites of the modified HB zeolite with hydrophobic surface improved the second-step CH 3 OH conversion activity. 143 …”

Heterogeneous Catalytic Hydrogenation of Carbon Dioxide Into Hydrocarbons: Achievements and Prospects

“…Analysis of the literature data showed that to date, noticeable activity in the hydrogenation of carbon dioxide to C2+ hydrocarbons has been established mainly for iron-containing catalysts with an oxide base [85][86][87]. In [88][89][90], C2+ hydrocarbons is characteristic of ironcontaining catalysts, while the Co and Ni catalysts selectively gave higher CH4 yields than other catalysts.…”

Heterogeneous Catalysis of CO₂ Hydrogenation to C₂₊ Products

“…and methanol-to-alkane transformation Alkane products can also be obtained through cascade Reproduced with permission from © 2017 Royal Society of Chemistry. catalysis combining methanol synthesis from CO2 hydrogenation, and a subsequent MTH reaction 70,93 . Typical catalysts for the methanol synthesis from CO2/H2 include Cu-based materials (Cu supported on ZnO 94 , Ga2O3 95 , ZrO2 96 ) and noble metals (Pd 97 , Pt 98 , Au 99 , Ag 100 ), while the commonly used catalysts for the MTH process are zeolites 101 .…”