Performance comparison of WO 3/SiO 2 to ZSM-5 and γ-Al 2O 3 in the catalytic dehydration of methanol

摘要

The performance of ZSM-5, γ-Al2O3and WO3/SiO2catalysts for the dehydration of methanol was studied in a fixed bed reactor over a temperature range of 150 to 450?°C and at atmospheric pressure. A parallel reaction scheme for dehydration of methanol to dimethyl ether and methane was proposed for the WO3/SiO2catalyst, and kinetic parameters for the two reactions were identified. The WO3/SiO2catalyst was less active than both ZSM-5 and γ-Al2O3for dehydration. At temperatures above 400?°C, experimental data indicated that WO3/SiO2could be producing heavier hydrocarbons than the other catalysts. The gas product for γ-Al2O3and WO3/SiO2also contained ethylene and methane whereas the gas product for ZSM-5 contained propane and propylene. At higher temperatures ZSM-5 produced gasoline range hydrocarbons but a similar product was absent from all experiments conducted using the WO3/SiO2and γ-Al2O3catalysts. It has been shown that WO3/SiO2can function as a methanol dehydration catalyst for the synthesis of dimethyl ether.