Conversion of methanol with C5-C6 hydrocarbons into aromatics in a two-stage fluidized bed reactor

The conversion of methanol mixed with C-5-C-6 hydrocarbons (including pentane, hexane, and cyclohexane) was studied in a two-stage fluidized bed reactor packed with 880 g Zn/ZSM-5 catalyst at 475 degrees C and 0.4 MPa. The effect of the mixed feed on the methanol conversion, self-decomposition of methanol, coke deposition on the catalyst, aromatic yield, and the aromatic distribution was carefully studied. Methanol conversion was nearly complete and the self -decomposition of methanol can be suppressed significantly. There exhibited a positive heat coupling effect in the feeding of methanol with pentane or with cyclohexane to increase the aromatic yield or to suppress the undesirable side reactions. However, the mixed feed is unfavorable to the transformation of hexane into aromatics. Better aromatic yield in the lower temperature for the mixed feed, as compared to that for the conversion of pure C-5-C-6 hydrocarbons in higher temperature, validated the heat coupling effect. The result confirmed that it is feasible to use the exothermic methanol conversion to enhance the endothermic transformation of some C-5-C-6 hydrocarbons into aromatic, resulting in a great engineering simplification of heat supply or heat removal in high temperature operation. (C) 2015 Elsevier B.V. All rights reserved.