| 摘要 |
A process for thermally cracking heavy hydrocarbons (e.g. naphtha, gas oil or residue) to olefins comprises: (a) diluting the feed with about 0.2 lb steam/lb feed; (b) heating the mixt. to cause partial cracking; (c) mixing a light hydrocarbon feed with steam; (d) cracking the mixt. from step (c) to completion; (e) mixing the prod. streams from steps (b) and (d), the latter providing heat and diluent for cracking the former; (f) further cracking the mixed stream; and (g) quenching the mixed stream. - Steam requirement for cracking the heavy hydrocarbon is reduced (e.g. from 1.07 to 0.48 lb/lb gas oil) without losing olefin yield. Capital and operating costs are correspondingly reduced. ((Dwg.0/2)) EPAB- EP-110433 B A process for the thermal cracking of heavy hydrocarbon feed to produce olefins, characterised by comprising the steps of: (a) diluting the heavy hydrocarbon feed with steam in a ratio of 0.2 or less kg of steam per kg of heavy hydrocarbon, while preheating the heavy hydrocarbon; (b) elevating the temperature of the heavy hydrocarbon with the steam diluent to a temperature to effect partial thermal cracking; (c) mixing a stream of light hydrocarbon feedstock which is lighter than the heavy hydrocarbon feed with steam diluent and elevating the temperature of the light hydrocarbon feedstock; (d) thermally cracking the light hydrocarbon feedstock to completion to produce principally olefins; (e) delivering the completely cracked light hydrocarbon effluent to the stream of partially cracked heavy hydrocarbon to form a composite stream, said light hydrocarbon effluent providing heat for subsequent cracking and serving as a diluent for the partially cracked heavy hydrocarbon; (f) further cracking the composite stream, and (g) quenching the effluent fromthe cracked composite stream of heavy and light hydrocarbon to terminate the reactions. GBAB- GB2128201 B A process for thermally cracking heavy hydrocarbons (e.g. naphtha, gas oil or residue) to olefins comprises: (a) diluting the feed with about 0.2 lb steam/lb feed; (b) heating the mixt. to cause partial cracking; (c) mixing a light hydrocarbon feed with steam; (d) cracking the mixt. from step (c) to completion; (e) mixing the prod. streams from steps (b) and (d), the latter providing heat and diluent for cracking the former; (f) further cracking the mixed stream; and (g) quenching the mixed stream. - Steam requirement for cracking the heavy hydrocarbon is reduced (e.g. from 1.07 to 0.48 lb/lb. gas oil) without losing olefin yield. Capital and operating costs are correspondingly reduced. USAB- US4492624 A Naphtha, kerosene, atmos. gas oil, vacuum gas oil, or resid heavy hydrocarbon feeds are thermally cracked to produce olefins. - Process comprises, (a) diluting feed with steam in ratio 0.2 lb or less of steam per lb of hydrocarbon; (b) raising temp. of mixt. to effect partial cracking; (c) mixing a stream of ethane, propane, propylene, normal- or isobutane, raffinate and/or naphthas of a light hydrocarbon feedstock with diluent; (d) thermally cracking light hydrocarbon feedstock to completion to form mainly olefins; (e) delivering cracked light hydrocarbon effluent to stream of partially cracked prod. from (b) to form composite stream, such that it provides heat for subsequent cracking and serves as diluent for latter; (f) further cracking composite; and (g) quenching effluent from (g) terminate reactions. |
