Aromatization of Methanol over La/Zn/HZSM-5 Catalysts

Aromatization of methanol over co-impregnated La/Zn/HZSM-5 zeolite catalyst was studied. The selectivity of aromatics and BTX (benzene, toluene, and xylene) reached 64.0% and 56.6%, respectively, using La/Zn/HZSM-5 at 437 °C, 0.1 MPa and methanol WHSV (weight hourly space velocity)0.8 h−1. Catalytic results showed that the La species was a very good promoter, increased selectivity of aromatics, and prolonged the catalyst lifetime on stream. The effects of the SiO2/Al2O3 ratio in zeolite, Zn and La loading, WHSV, reaction temperature, water content in the feed and H2 pretreatment of catalysts on the catalytic performance were studied in detail. Characterizations of the catalysts by thermogravimetric analysis (TGA), NH3-TPD (temperature programmed desorption), SEM (scanning electron micrograph), N2 adsorption-desorption, XRD (X-ray diffraction) and XRF (X-ray fluorescence), were carried out to understand the structure and discuss the aromatization performance of La/Zn/HZSM-5 zeolite catalyst.