Dimethyl Ether Conversion to Light Olefins on Zeolite Catalysts: Effect of MFI-Type Zeolite Nature and SiO2/Al2O3 Molar Ratio on Catalyst Efficiency

The physicochemical and catalytic properties of magnesium-containing zeolite catalysts based on MFI-type zeolites (ZSM-5 and CBV) were compared. The presence of larger mesopores volume in MgCBV was found to decrease selectivity towards light olefins. In order to improve the catalytic properties of MgCBV, the effect of SiO 2 /Al 2 O 3 molar ratio of CBV (SiO 2 /Al 2 O 3 = 30, 55, 80 and 300) on its physicochemical and catalytic properties in the reaction of the dimethyl ether (DME) into light olefins was studied. Increasing SiO 2 /Al 2 O 3 molar ratio from 30 to 80, was shown not change practically the DME conversion and olefin selectivity, but under a SiO 2 /Al 2 O 3 molar ratio of 300, DME conversion significantly reduces, olefin selectivity increases, while the ethylene/propylene ratio decreases twice. By changing residence time, DME conversion increases under high total light olefins selectivity, while the ethylene/propylene ratio raises with increasing residence time. Graphic Abstract