| 主权项 |
1. Process for mild hydrocracking of a fraction of the VGO, DSV or DAO type for the purpose of constituting the feedstock of a catalytic cracking unit, comprising:
A mild hydrocracking zone R, A high-pressure hot separator tank B-1, whose feedstock constitutes the effluent obtained from R, A high-pressure cold separator tank B-2, whose feedstock constitutes the gas stream obtained from B-1, A low-pressure cold separator tank B-3, whose feedstock is the liquid stream obtained from B-2, A zone K-1 for washing with an amine and for compression of the gaseous effluent obtained from B-2, called recycled hydrogen, A pump P-2 compressing the VGO feedstock before mixing with the recycled hydrogen obtained from K-1 and with the addition of hydrogen, A stripper C-1 of the liquid streams obtained from B-1 and B-3, whose bottom product constitutes the feedstock of the fractionator C-2, A fractionator C-2, separating the naphtha, the diesel and the residue, and comprising a diesel-circulating reflux, A diesel stripper C-3, stripping the diesel obtained from C-2, A furnace F-1 heating the feedstock of the mild hydrocracking zone R, A furnace F-2 heating the feedstock of the fractionator C-2,process comprising optimized heat exchanges between different streams at different levels of said process, or:
a) At the exchange train of the heating of the low-pressure feedstock, by exchange:
In E-8 with the stripped diesel obtained from C-3,Then, in E-4 with the diesel-circulating reflux,Then in E-7 with the bottom of the fractionator C2, with E-7 being able to consist of several calendars in a series (denoted E-7 A/B), b) At the exchange train of the cooling of the gaseous effluent obtained from B-1, by exchange:
In E-2 A and E-2 B with the liquid obtained from B-3,In E-9 with the high-pressure feedstock mixed with hydrogen,In E-3 A and E-3 B with the mixture of the addition of hydrogen and a part of the recycled hydrogen,In the following order: E-2 A, E-9, E-3 A, E-2 B, and then E-3 B, c) At the exchange train of the cooling of the effluent of the mild hydrocracking zone R, by exchange:
In E-1 with the high-pressure feedstock of R, with E-1 consisting of several calendars,In E-10 with the feedstock of the fractionator C-2, with E-10 being able to consist of several calendars and the calendars being able to be located between calendars of E-1, d) At the exchange train of the cooling of the bottom of the fractionator C-2, by exchange:
First in E-5 with the diesel for reboiling the diesel stripper C-3,Then in E-6 with the feedstock of the fractionator C-2,process characterized in that all of the preceding heat exchanges make it possible to reduce the cumulative power of the furnaces F-1 and F-2 by a factor of 0.35 to 0.6 relative to the configuration of the prior art. |
