Investigation of the effect of H-ZSM-5 zeolite synthesized by various sources of silicon on the conversion of methanol to propylene (MTP)

Conversion of methanol, produced from natural gas or coal, to liquid hydrocarbon by zeolite catalysts can be a promising way to save oil reserves(1). According to the literature, H-ZSM-5 zeolite has better performance in the MTP process (2, 3). In this work H-ZSM-5 zeolite catalyst (Si/Al=200) was synthesized by hydrothermal method from various sources of silicon, including Ludox (LHZ), Silicic acid (SHZ), and tetraethyl orthosilicate (THZ). The samples characterization were confirmed using X-ray diffraction (XRD) analysis and fourier-transform infrared (FT-IR) spectroscopy. The relative crystallinity (4) and particle size were compared. Also, LHZ sample characterized by scanning electron microscopy (SEM) and Brunauer–Emmett–Teller (BET) measurements. The catalysts evaluation were performed for all samples in a fixed-bed reactor at 480 °C, 1 bar, methanol weight hourly space velocity (WHSV) of 1 h-1 and using feed with methanol to water weight ratio of unity. In order to study the effect of temperature and WHSV on the catalyst performance, LHZ sample studied at four temperatures (420, 450, 480, 510 ℃) and three WHSV (1, 2, 3 h-1). According to the results obtained from LHZ, SHZ and THZ samples, LHZ with 99.85% methanol conversion and 55.55% propylene selectivity at optimized conditions T=480°C, WHSV= 1h-1, P= 1atm, MeOH/H2O= 1Wt had the best performance in the MTP process