Methanol/dimethyl ether to light olefins over SAPO-34: Comprehensive comparison of the products distribution and catalyst performance

Dimethyl Ether (DME) as a possible reactant for production of light olefins was compared with methanol over a synthesized SAPO-34 catalyst at 400–460 °C and the productsʹ distributions as a function of time on stream and reaction temperature were reported and analyzed. Physiochemical characteristics of the synthesized SAPO-34 catalyst were determined by BET, TPD, XRD, SEM and XRF techniques. The optimum reaction temperature range for methanol conversion to olefins (MTO) seemed to be 400–460 °C with the light olefinsʹ selectivity of 77–78.5% and C2=/C3= molar ratios from 1.6 at 400 °C to 2.4 at 460 °C. Productsʹ distributions in DME to olefins (DTO) reaction were different from MTO reaction specially at methane and light olefinsʹ formation rates. Life time of the catalyst increased while using dimethyl ether as the feed but due to high rates of methanol and methane formation, the light olefinsʹ selectivities were not as high as those of MTO reaction.