Process for the conversion of a heavy hydrocarbon feedstock integrating selective cascade deasphalting with recycling of a deasphalted cut

Patent metadata

Field	Value
Publication number	US-9982203-B2
Application number	US-201415100745-A
Country	US
Kind code	B2
Filing date	Nov 27, 2014
Priority date	Dec 3, 2013
Publication date	May 29, 2018
Grant date	May 29, 2018

Abstract

Process for converting a heavy hydrocarbon feedstock with initial boiling point of at least 300° C. comprising: a) hydroconverting at least part of said feedstock; b) separating the effluent from stage a) to obtain light and heavy liquid fractions; c) at least two stages of deasphalting in series at least part of the heavy liquid fraction originating from stage b), allowing to separate at least one fraction of asphalt, at least one fraction of heavy deasphalted oil (heavy DAO) and at least one fraction of light deasphalted oil (light DAO), at least one deasphalting stage being carried out using a mixture of at least one polar solvent and at least one apolar solvent, said deasphalting stages being under subcritical conditions of the mixture of solvents; d) recycling at least part of said heavy deasphalted oil cut from stage c) upstream of hydroconverting a) and/or of the inlet of separating b).

First claim

The invention claimed is:

1. Process for the conversion of a heavy hydrocarbon feedstock having an initial boiling point of at least 300° C. comprising the following stages:
a) a stage of hydroconverting at least a part of said feedstock in the presence of hydrogen in at least one three-phase reactor, said reactor containing at least one hydroconversion catalyst and operating as an ebullating bed, with ascending flow of liquid and of gas and comprising at least one means for drawing off said catalyst from said reactor and at least one means for supplying fresh catalyst to said reactor, under conditions to obtain a liquid feedstock with a reduced content of Conradson carbon, metals, sulphur and nitrogen;
b) a stage of separating the effluent originating from stage a) in order to obtain a light liquid fraction with a boiling point lower than 300° C. and a heavy liquid fraction with a boiling point greater than 300° C.;
c) at least two stages of deasphalting in series on at least a part of the heavy liquid fraction originating from stage b), making it possible to separate at least one fraction of asphalt, at least one fraction of heavy deasphalted oil, referred to as heavy DAO, and at least one fraction of light deasphalted oil, referred to as light DAO, at least one of said stages of deasphalting being carried out by means of a mixture of at least one polar solvent and at least one apolar solvent, the proportions of said polar solvent and said apolar solvent in the mixture of solvents being adjusted depending on the properties of the feedstock treated and depending on the desired yield of asphalt and/or quality of the deasphalted oil, said stages of deasphalting being implemented under the subcritical conditions of the mixture of solvents used; and
d) a stage of recycling at least a part of said heavy deasphalted oil cut referred to as heavy DAO originating from stage c) upstream of the stage a) of hydroconverting and/or to the inlet of the stage b) of separating.

2. Process according to claim 1 , in which stage a) is implemented in one or more three-phase hydroconversion reactors with intermediate settler drums.

3. Process according to claim 1 , in which stage c) is implemented on at least a part of the heavy fraction previously subjected to a stage of steam stripping and/or hydrogen stripping or to a stage of vacuum fractionation.

4. Process according to claim 1 , in which the stage a) of hydroconverting is carried out under an absolute pressure comprised between 2 and 35 MPa, at a temperature comprised between 300 and 550° C., at a hourly space velocity (HSV) comprised between 0.1 h −1 and 10 h −1 and with a quantity of hydrogen mixed with the feedstock comprised between 50 and 5000 normal cubic meters (Nm 3 ) per cubic meter (m 3 ) of liquid feedstock.

5. Process according to claim 1 , in which at least a part of the fraction of light deasphalted oil referred to as light DAO is sent to a post-treatment unit.

6. Process according to claim 1 , in which at least a part of the heavy deasphalted oil cut referred to as heavy DAO not recycled upstream of the stage a) of hydroconverting and/or to the inlet of the stage b) of separating is sent to a post-treatment unit.

7. Process according to claim 1 , in which the hydroconversion catalyst is a catalyst comprising an alumina support and at least one group VIII metal selected from nickel and cobalt, said group VIII element being used in combination with at least one group VIB metal selected from molybdenum and tungsten.

8. Process according to claim 1 , in which stage c) comprises at least:
c1) a first stage of deasphalting comprising bringing the heavy liquid fraction into contact with a mixture of at least one polar solvent and at least one apolar solvent, the proportions of said polar solvent and of said apolar solvent being adjusted so as to obtain at least one fraction of asphalt phase and a fraction of complete deasphalted oil phase referred to as complete DAO; and
c2) a second stage of deasphalting comprising bringing the complete deasphalted oil phase referred to as complete DAO originating from stage c1) into contact with either an apolar solvent or a mixture of at least one polar solvent and at least one apolar solvent, the proportions of said polar solvent and of said apolar solvent in the mixture being adjusted so as to obtain at least one fraction of light deasphalted oil phase referred to as light DAO and a fraction of heavy deasphalted oil phase referred to as heavy DAO,
said stages of deasphalting being implemented under the subcritical conditions of the solvent or mixture of solvents used.

9. Process according to claim 8 , in which the complete deasphalted oil referred to as complete DAO originating from stage c1) with, at least in part, the mixture of solvents is subjected to at least one stage of separation in which the complete deasphalted oil referred to as complete DAO is separated from the mixture of solvents or at least one stage of separation in which the complete deasphalted oil referred to as complete DAO is separated only from the apolar solvent.

10. Process according to claim 8 , in which the complete deasphalted oil referred to as complete DAO originating from stage c1) with, at least in part, the mixture of solvents is subjected to at least two successive stages of separation allowing the solvents to be separated individually in each stage.

11. Process according to claim 1 , in which stage c) comprises at least:
c′1) a first stage of deasphalting comprising bringing the heavy liquid fraction into contact with either an apolar solvent, or a mixture of at least one polar solvent and at least one apolar solvent, the proportions of said polar solvent and said apolar solvent in the mixture being adjusted so as to obtain at least one fraction of light deasphalted oil phase referred to as light DAO and an effluent comprising an oil phase and an asphalt phase; and
c′2) a second stage of deasphalting comprising bringing the effluent originating from stage c′1) into contact with a mixture of at least one polar solvent and at least one apolar solvent, the proportions of said polar solvent and of said apolar solvent being adjusted so as to obtain at least one fraction of asphalt phase and a fraction of heavy deasphalted oil phase referred to as heavy DAO,
said stages of deasphalting being implemented under the subcritical conditions of the solvent or mixture of solvents used.

12. Process according to claim 11 , in which the effluent from stage c′ 1) is subjected to at least one stage of separation, in which it is separated from the apolar solvent or mixture of solvents or at least one stage of separation, in which said effluent is separated only from the apolar solvent contained in the mixture of solvents.

13. Process according to claim 11 , in which the effluent from stage c′ 1) is subjected to at least two successive stages of separation making it to separate the solvents individually in each stage of separation.

14. Process according to claim 1 , in which the polar solvent used in the stage c) of deasphalting is selected from pure aromatic or naphthene-aromatic solvents, the polar solvents comprising heteroelements, or a mixture thereof or cuts rich in aromatics.

15. Process according to claim 1 , in which the apolar solvent used in the stage c) of deasphalting comprises a solvent made up of a saturated hydrocarbon comprising a number of carbon atoms greater than or equal to 2.

16. Process according to claim 1 , in which stage c) is implemented with a ratio of the volume of the mixture of polar and apolar solvents to the mass of the fee

Assignees

• Ifp Energies Now

Inventors

• Majcher Jerome
• Merdrignac Isabelle
• Feugnet Frederic

Classifications

• C10G2300/206

  Asphaltenes · CPC title

• C10G2300/205

  Metal content · CPC title

• C10G53/06

  including only extraction steps, e.g. deasphalting by solvent treatment followed by extraction of aromatics · CPC title

• C10G45/20

  according to the "fluidised-bed" technique · CPC title

• C10G2300/1014

  of vegetal origin · CPC title