Patent ID: 11898108
Assignee: AXENS
Field: Chemical engineering (Chemistry)
Classification: CPC C  B | IPC B  C

Claim 18:
19. A plant for hydrocracking a petroleum feedstock comprising at least 10% by volume of compounds that boil above 340° C., said plant successively comprising:
(a) at least one section (2) for hydrocracking the feedstock (1) in order to obtain a hydrocracked effluent,
(b) at least one section (4) for liquid/gas separation of the hydrocracked effluent in order to obtain a gaseous effluent (5) and a liquid effluent (9),
(c) a section for fractionating said liquid effluent, comprising at least one column (12), at a pressure P1 at the bottom of the column, to produce at least a first distillate (13, 14) and a first residue (15),
(d) a line for recycling a first portion (18) of said first residue (15) to one of the at least one hydrocracking section (2),
(e) a section for rectifying a second portion (20) of the first residue (15) obtained in the fractionating zone, comprising at least one column (21), at a pressure P2 at the top thereof which is at least 0.05 MPa lower than the pressure P1, to obtain at least a secondary distillate (23), a secondary residue (16) and a vapor stream (22),
(f) a section for purging at least one portion, or all, of the secondary residue (16), and
(g) a line for recycling all or part of said secondary distillate (23) to the hydrocracking section (2) or at least one of the hydrocracking sections, after an optional gas separation section,
wherein said plant is free of a line for recycling all or part of the of the overhead vapor stream (22) resulting from the rectifying step (e).