Effect of crystal size on the catalytic performance of HZSM-5 Zeolite in the methanol to aromatics reaction

ABSTRACT

The effect of crystal size on the lifetime and product distribution of HZSM-5 catalysts in methanol to aromatics reaction has been investigated. Increasing crystal size results in a reduction of the lifetime. Though the initial selectivity of total aromatics is approximately the same, larger crystal size favors the dealkylation reactions of polymethylbenzenes, cracking of C₅–C₉ non-aromatics and hydrogen transfer reaction, leading to different product distribution. The longer lifetime of HZSM-5 with smaller crystal size can be attributed to its larger specific surface area, pore volume and diameter and short residence time of the reaction products in the zeolite pores.

KEYWORDS:

• crystal size
• HZSM-5 zeolites
• lifetime
• methanol to aromatics
• product distribution