Process for hydrotreatment of a heavy hydrocarbon fraction using permutable reactors and introduction of a middle distillate

• US 6,306,287 B1
• Filed: 10/14/1999
• Issued: 10/23/2001
• Est. Priority Date: 10/14/1998
• Status: Expired due to Term

• Current Assignee: Institut Francais Du Petrole
• Original Assignee: Institut Francais Du Petrole
• Inventors: Kressmann, Stéphane, Morel, Frédéric, Kim, Sun Dong, Ha, Sung Ki, Heor, Haen, Billon, Alain
• Primary Examiner(s): GRIFFIN, WALTER DEAN
• Application Number:
  US09/417,766
• Time in Patent Office: 740 Days
• Field of Search: 208/210, 208/211, 208/212, 208/251.H
• US Class Current: 208/211
• CPC Class Codes: C10G 65/04 including only refining steps

Abstract

A hydrotreatment process is carried out in at least two steps to hydrotreat a heavy hydrocarbon fraction containing asphaltenes, sulphur-containing impurities and metallic impurities, comprising a first hydrodemetallization step and a subsequent second hydrodesulphurization step, in which the hydrodemetallization step comprises one or more hydrodemetallization zones with fixed beds preceded by at least two hydrodemetallization guard zones (A) and (B), also with fixed beds, disposed in series for cyclic use consisting of successive repetition of steps b) and c) defined below. The process comprises the following steps: a) a step in which the guard zones are used together for a period of at most equal to the deactivation time and/or clogging time of one thereof, b) a step during which the deactivated and/or clogged guard zone is short-circuited and the catalyst it contains is regenerated and/or replaced by fresh catalyst, and c) a step during which the guard zones (A) and (B) are used together, the guard zone where the catalyst has been regenerated during the preceding step being reconnected and said step being carried out for a period at most equal to the deactivation and/or clogging time of one of the guard zones. The process is characterized by introducing a quantity of middle distillate, particularly a gas oil, with the feed representing 0.5% to 80% by weight with respect to the feed. The process can comprise a prior hydrovisbreaking step and optionally a final deasphalting step using a solvent.

Claims

1. A process for hydrotreating a heavy hydrocarbon fraction containing asphaltenes, sulphur-containing impurities and metallic impurities in at least two steps, comprising during the first step, hydrodemetallisation, passing the heavy hydrocarbon fraction and hydrogen over a hydrodemetallisation catalyst under hydrodemetallisation conditions, and during the subsequent second step, passing resultant effluent from the first step over a hydrodesulphurisation catalyst under hydrodesulphurisation conditions, in which the hydrodemetallisation step comprises one or more hydrodemetallisation zone with fixed catalyst beds preceded by at least two hydrodemetallisation guard zones also with fixed catalyst beds, disposed in series for cyclic use comprising successive repetition of steps b) and c) defined below:

a) a step comprising passing the heavy hydrocarbon fraction through all the guard zones for a period of at most equal to the deactivation time and/or clogging time for one thereof;

b) a step during which the deactivated and/or clogged guard zone is short-circuited and the catalyst the short circuited guard zone contains is regenerated and/or replaced by fresh catalyst; and

c) a step during which the guard zones are all used together, the guard zone where the catalyst has been regenerated and/or replaced by fresh catalyst during the preceding step, being reconnected, and said step being carried out for a period at most equal to the deactivation and/or clogging time for one of the guard zones;

said process being characterized in that a quantity of gas oil representing 0.5% to 80% by weight with respect to the weight of the hydrocarbon feed is introduced into the inlet to the first functioning guard zone at the same time as the feed; and

said process further comprises passing product from the hydrodesulphurisation to an atmospheric distillation zone, from which an atmospheric distillate is recovered and recycling at least a portion of said atmospheric distillate comprising a gas oil to the inlet of the first functioning guard zone and recovering an atmospheric residue.

2. A process according to claim 1, in which a portion of the gas oil is a straight run gas oil.

3. A process according to claim 2, in which the straight gas oil fraction is a cut with an initial boiling point of about 150°

C. and an end point of about 370°

C.

4. A process according to claim 1, in which the quantity of gas oil introduced into the inlet to the first functioning guard zone at the same time as the feed represents about 1% to 50% by weight with respect to the feed.

5. A process according to claim 1, in which at least a portion of the atmospheric residue from the atmospheric distillation zone is sent to a vacuum distillation zone from which a vacuum distillate is recovered at least a portion of which is recycled to the inlet to the first functioning guard zone, and a vacuum residue is also recovered.

6. A process according to claim 5, further comprising deasphalting the vacuum residue using a solvent or a solvent mixture and recycling at least a portion of the deasphalted product to the inlet to the first functioning guard zone.

7. A process according to claim 5, in which, in order to treat a feed constituted by a heavy oil or a fraction of a heavy oil containing asphaltenes, the feed is first mixed with hydrogen and subjected to hydrovisbreaking before sending the feed to the guard zones.

8. A process according to claim 1, in which at least a portion of the atmospheric residue and/or a vacuum distillate is sent to a catalytic cracking unit from which an LCO fraction and an HCO fraction are recovered, at least a portion of either one or the other or a mixture of the two is went to the inlet to the first functioning guard zone.

9. A process according to claim 8, in which, in order to treat a feed constituted by a heavy oil or a fraction of a heavy oil containing asphaltenes, the feed is first mixed with hydrogen and subjected to hydrovisbreaking before sending the feed to the guard zones.

10. A process according to claim 1 in which during step c) the guard zones are all used together, the guard zone in which the catalyst has been regenerated and/or replaced during step b) being reconnected such that its connection is identical to that which it had before it was short-circuited during step b).

11. A process according to claim 1 comprising the following steps:

a) a step in which the guard zones are used all together for a period at least equal to the deactivation and/or clogging time of the most upstream guard zone with respect to the overall direction of circulation of the treated feed;

b) a step during which the feed penetrates directly into the guard zone located immediately after that which was the most upstream during the preceding step and during which the guard zone which was the most upstream during the preceding step is short-circuited and the catalyst it contains is regenerated and/or replaced by fresh catalyst; and

c) a step during which the guard zones are used all together, the guard zone in which the catalyst has been regenerated and/or replaced during the preceding step being reconnected so as to be downstream of the set of guard zones and said step being continued for a period at most equal to the deactivation and/or clogging time of the guard zone which during this step is the most upstream with respect to the overall direction of circulation of the treated feed.

12. A process according to claim 1, in which a conditioning section is associated with the guard zones to allow permutation of the guard zones during operation, without stopping the unit, said section being adjusted so as to condition the catalyst contained in the guard zone which is not operating, to a pressure in the range 10 to 50 bars.

13. A process according to claim 1 in which, in order to treat a feed constituted by a heavy oil or a fraction of a heavy oil containing asphaltenes, the feed is first mixed with hydrogen and subjected to hydrovisbreaking, before sending the feed to the guard zones.

14. A process according to claim 1, further comprising deasphalting the atmospheric residue using a solvent or a solvent mixture and recycling at least a portion of the deasphalted product to the inlet to the first functioning guard zone.

15. A process for hydrotreating a heavy hydrocarbon fraction containing asphaltenes, sulphur-containing impurities and metallic impurities in at least two steps, comprising during the first step, hydrodemetallisation, passing the heavy hydrocarbon fraction and hydrogen over a hydrodemetallisation catalyst under hydrodemetallisation conditions, and during the subsequent second step, passing resultant effluent from the first step over a hydrodesulphurisation catalyst under hydrodesulphurisation conditions, in which the hydrodemetallisation step comprises one or more hydrodemetallisation zone with fixed catalyst beds preceded by at least two hydrodemetallisation guard zones also with fixed catalyst beds, disposed in series for cyclic use comprising successive repetition of steps b) and c) defined below:

a) a step comprising passing the heavy hydrocarbon fraction through all the guard zones for a period of at most equal to the deactivation time and/or clogging time for one thereof;

b) a step during which the deactivated and/or clogged guard zone is short-circuited and the catalyst the short circuited guard zone contains is regenerated and/or replaced by fresh catalyst; and

c) a step during which the guard zones are all used together, the guard zone where the catalyst has been regenerated and/or replaced by fresh catalyst during the preceding step, being reconnected, and said step being carried out for a period at most equal to the deactivation and/or clogging time for one of the guard zones;

said process being characterized in that a quantity of gas oil representing 0.5% to 80% by weight with respect to the weight of the hydrocarbon feed is introduced into the inlet to the first functioning guard zone at the same time as the feed; and

said process further comprises passing product from the hydrodesulphurisation to a distillation zone, from which a distillate is recovered and recycling at least a portion of said distillate comprising a gas oil to the inlet of the first functioning guard zone and recovering a residue.