Process for producing C2 and C3 hydrocarbons

摘要

The present invention relates to a process for producing C2 and C3 hydrocarbons, comprising: a) subjecting a mixed hydrocarbon stream comprising middle distillate to a first hydrocracking in the presence of a first hydrocracking catalyst; Producing a hydrocracking product stream of b, subjecting the second hydrocracking feed stream to a second hydrocracking in the presence of a second hydrocracking catalyst to produce a second hydrocracking product Producing a product stream, wherein the second hydrocracking is more severe than the first hydrocracking, and c) the C4 hydrocracking feed stream in the presence of a C4 hydrocracking catalyst, C4 hydrocracking optimized to convert C4 hydrocarbons to C3 hydrocarbons to obtain a C4 hydrocracking product stream, the C4 hydrocracking being more than the second hydrocracking Including strict, process, One hydrocracked product stream, a second hydrocracked product stream and a C4 hydrocracked product stream are fed to a separation system, which separates from the first hydrocracked product stream Second hydrocracked feed stream, C4 hydrocracked feed stream separated from the second hydrocracked product stream, first recycle stream recycled back to the first hydrocracking A second recycle stream that is recycled back to the second hydrocracking, a third recycle stream that is recycled back to the C4 hydrocracking, a first hydrocracking, a second hydrogenation H2 or H2 and C1 hydrogen recycle stream recycled back to cracking and / or C4 hydrocracking, and -C3 Providing a C2 and C3 product stream of hydrocarbons, the second hydrocracking feed stream is a C12-hydrocarbon stream excluding C10-C12 hydrocarbons having a bicyclic structure, and the first recycle stream is C13 + And a C10-C12 hydrocarbon stream having a bicyclic structure, a C4 hydrocracking feed stream is a C5-, C4- or iC4- stream, and a second recycle stream is a C6 +, C5 + or nC4 + stream. Yes, the third recycle stream is an nC4 + or C4 + stream.