PROCESS FOR THE PRODUCTION OF OLEFINS BY CONVERSION OF METHANOL AND (OR) DIMETHYL ETHER

摘要

1. A process for the preparation of C2 -C4 -olefins in two stages by converting methanol and/or dimethyl ether over a zeolite catalyst of the pentasil type at from 300 to 600 degrees C and then subjecting some of the products to a cracking procedure, wherein, in the first stage, at least 95% of the crude methanol and/or the dimethyl ether is converted over a borosilicate zeolite or an aluminosilicate zeolite which has been treated with steam for at least 4 hours at above 400 degrees C, using a catalyst load of from 0,1 to 100 g of methanol and/or dimethyl ether per g of catalyst per hour, and a pressure of from 1 to 3 bars, into a mixture of hydrocarbons which contains less than 15% by weight of aromatic compounds, and the C2 -C4 -olefins formed are isolated and the C5-+ hydrocarbons together with the C2 -C4 -parafins are subjected to thermal cleavage in the presence of steam.