A method of producing ethylene by using refinery C4

摘要

A method of producing ethylene by using refinery C4 comprising: a refinery C4 as a first raw material which comprises 45%-55% isobutane, 5%-10% n-butane, 15%-20% isobutene, 10%-15% 1-butylene and 5%-10% 2-butylene based on the total weight percentage of the refinery C4, the weight average molecular weight thereof being 55-60, an alkane-rich light hydrocarbon as a second raw material which comprises 40%-50% linear alkane, 25%-35% branched alkane, 15%-25% cyclane, less than or equal to 1% alkene and less than or equal to 10% arene based on the total weight percentage of the alkane-rich light hydrocarbon, the weight average molecular weight thereof being 90-100; the refinery C4 being in amount of about 10% to about 30% of the total weight percentage of the refinery C4 and alkane-rich light hydrocarbon; introducing the mixture of said first raw material and said second raw material into the upper part of the convection section of a cracking furnace, after diluted with steam, passing the diluted mixture through the lower part of the convection section to enter into the radiation section of said cracking furnace, distributing the diluted mixture to manifolds to carry out copyrolysis reaction therein so as to produce ethylene, wherein the cracking temperature is about 840°C to about 860°C, and the dilution ratio of steam/total raw materials is about 0.30 to about 0.60 wt/wt. According to the method provided in the present invention, the yield of ethylene attributed to the refinery C4 of the total raw materials can be greatly increased as compared with the separate cracking of refinery C4, while the cracking performance of light hydrocarbon can be maintained. In this way, the use value of refinery C4 and also other C4-rich products can be effectively improved, thus notable economic bendfits can be brought to the oil refinery.