PRODUCTION OF OLEFINS

摘要

A process for steam cracking a hydrocarbon feedstock containing olefins to provide increased light olefins in the steam cracked effluent, the process comprising passing a first hydrocarbon feedstock containing one or more olefins through a reactor containing a crystalline silicate to produce an intermediate effluent with an olefin content of lower molecular weight than that of the feedstock, fractionating the intermediate effluent to provide a lower carbon fraction and a higher carbon fraction, and passing the higher carbon fraction, as a second hydrocarbon feedstock, through a stream cracker to produce a steam cracked effluent. There is also provided a process for steam cracking a hydrocarbon feedstock containing olefins to provide increased light olefins in the steam cracked effluent, the process comprising passing a first hydrocarbon feedstock containing one or more olefins, which comprises at least one of a hydrotreated raw C4 feedstock, LCCS, a raffinate 2 feedstock, a raffinate 1 feedstock, a raffinate 2 feedstock from a methyl tert-butyl ether (MTBE) or an ethyl tert-butyl ether (ETBE) unit, a raffinate from an olefins metathesis unit, in particular for the production of propylene from ethylene and butene, or a hydrotreated olefin-containing stream from an FCC unit, a visbreaker or a delayed coker, through a reactor containing a crystalline silicate to produce an intermediate effluent with an olefin content of lower molecular weight than that of the feedstock, and passing the intermediate effluent as a second hydrocarbon feedstock through a steam cracker to produce a steam cracked effluent. There is further provided a process for steam cracking a hydrocarbon feedstock containing olefins to provide increased light olefins in the steam cracked effluent, the process comprising steam cracking a first hydrocarbon feedstock comprising a paraffin-containing hydrocarbon feedstock and steam cracking a second hydrocarbon feedstock which contains C4 and higher hydrocarbons, the second hydrocarbon feedstock containing one or more olefins and comprising a bottom fraction of an intermediate effluent produced by catalytic cracking of a third hydrocarbon feedstock in a reactor containing a crystalline silicate to produce the intermediate effluent having an olefin content of lower molecular weight than that of the third feedstock, and combining the two steam-cracked effluents to provide a common effluent.