C1-C4 Hydrocarbons from synthesis gas -: Reaction network modelling

Compound catalysts offering both methanol synthesis and methanol conversion functions were used to produce C-1-C-4 hydrocarbons from a reactant mixture of 1:1 CO:H-2 synthesis gas. The catalyst pellets were composed of 63 wt% methanol synthesis component which was a zinc and chromium mixed oxide, 27 wt% methanol conversion component which was zeolite ZSM-5 modified by the addition of phosphorus (phosphorus levels 2.0-4.5 wt% of ZSM-5), and 10 wt% alumina binder. The catalysts were characterized using XRD, SEM-EDX, BET, and TPD. The catalysts were tested under reaction conditions in a Berty well-mixed fixed bed reactor. It was found that: (a) the CO conversion was higher than it would be expected given thermodynamic limitations of traditional methanol synthesis, indicating a "drain-off" effect of the bi-functional catalyst; (b) the water-gas shift reaction occurred at thermodynamic equilibrium; (c) the production of hydrocarbons larger than C-4 was prevented. (C) 1999 Elsevier Science Ltd. All rights reserved.