Study of Methanol Conversion to Olefin and Study of Lanthanum Loading and Si/Al Ratio Parameters on HZSM-5 Catalyst

Recently, catalytic technologies for the conversion of methanol to olefins have been very much considered. In the present paper, the effect of lanthanum loading parameters and Si/Al ratios at different temperatures on the catalytic function of HZSM-5 in the methanol-olefin conversion process was investigated. In this paper, the catalytic base of HZSM-5 with different Si/Al ratios was modified using the lanthanum metal and wet impregnation method. After loading of lanthanum metal by wet impregnation, the modified catalysts were subjected to XRD, SEM, BET, and FT-IR analysis for accurate determination of their specification and evaluation. The results of XRD and FT-IR analysis showed that the addition of lanthanum metal to HZSM-5 zeolite did not cause structural damage. The structure after the addition of lanthanum metal still had high crystallinity. The design of the Box-Behnken test was used to investigate the effect of lanthanum parameters, Si/Al ratio, and temperature, and investigate the effect of interactions between them for the production of ethylene and propylene in the methanol-olefin process. For this purpose, loading of lanthanum in the range of 0-10% by weight, the Si/Al ratio in the range of 180-160 °C, and temperature in the range of 350-450 °C were used as input variables of the Box-Behnken method. Using the results of the design of the Box-Behnken test, it was found that the highest ethylene yield was achieved on a catalyst that was at the highest level of loading of lanthanum, low Si/Al ratio and high temperature. For optimum propylene production, there was an optimal mode for three variables: Si/Al ratio, temperature, and loading rate of lanthanum, which initially increased the propylene yield and then decreased with increasing of these variables.