Catalyst for preparing ethylene and propylene by using methyl alcohol and/or dimethyl ether, and preparation method and application of ethylene and propylene

摘要

A catalyst for preparing ethylene and propylene by using methyl alcohol and/or dimethyl ether is provided. The catalyst is a mesoporous molecular sieve catalyst obtained through combined lanthanum and silanization modification. The steps of using the catalyst to prepare ethylene and propylene by using methyl alcohol and/or dimethyl ether comprise: feeding methyl alcohol and/or dimethyl ether, to enable the methyl alcohol and/or dimethyl ether to contact the catalyst, generating reaction to produce hydrocarbons; separating the hydrocarbons into components containing one to five carbon atoms and components containing more than six carbon atoms; returning the components containing more than six carbon atoms to a feeding port of a reactor, and mixing the components containing more than six carbon atoms with methyl alcohol and/or dimethyl ether; performing cyclic operation. Ethylene and propylene selectively reach more than 90% by weight in the components containing one to five carbon atoms obtained through separation, thereby implementing a maximum yield in preparing ethylene and propylene by using methyl alcohol and/or dimethyl ether.