Conversion of methanol to aromatics in fluidized bed reactor

• Methanol to aromatics conducted in fluidized bed.
• Intermediate product of C5+ alkane and alkene was capably converted into aromatics.
• Inhibition of gas backmixing in two stage fluidized bed produces more aromatics.

Conversion of methanol to aromatics (MTA) was conducted over a fresh or a spent Zn/ZSM-5 catalyst in single stage fluidized bed (SSFB) and two stage fluidized bed (TSFB). Sampling at different stages of TSFB and operation in the temperature range of 250, 275, 300, 325, 350, 380 and 475 °C revealed the consecutive reaction mode from methanol to DME, C1–C4 hydrocarbons, C5+ nonaromatics to aromatics finally. High weight ratio of para-xylene (PX) in xylene in wide temperature range suggested that PX was the primary product of MTA, and other xylenes are produced by the iosmerization of PX. Other aromatics such as benzene, toluene and trimethylbenzene are finally produced by the dealkylation, alkylation or disproportionation of xylene. The adoption of TSFB reactor was effective to increase the yield of aromatics, compared to that using SSFB, due to the inhibition of backmixing of gases. Combination of TSFB and highly active catalyst with strong acids was effective to get high yield of aromatics under high space velocity of methanol.

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