Hydroprocessing thermally cracked products

Patent metadata

Field	Value
Publication number	US-9631150-B2
Application number	US-201414180623-A
Country	US
Kind code	B2
Filing date	Feb 14, 2014
Priority date	Mar 15, 2013
Publication date	Apr 25, 2017
Grant date	Apr 25, 2017

Abstract

Embodiments herein relate to a process flow scheme for the processing of gas oils and especially reactive gas oils produced by thermal cracking of residua using a split flow concept. The split flow concepts disclosed allow optimization of the hydrocracking reactor seventies and thereby take advantage of the different reactivities of thermally cracked gas oils versus those of virgin gas oils. This results in a lower cost facility for producing base oils as well as diesel, kerosene and gasoline fuels while achieving high conversions and high catalyst lives.

First claim

What is claimed:

1. A process for upgrading gas oils to distillate hydrocarbons, the process comprising:
dividing a first gas oil stream into a first and second portions of equal composition;
mixing a second gas oil stream and the first portion of the first gas oil stream to form a mixed gas oil stream;
contacting the mixed gas oil stream and hydrogen with a first hydroconversion catalyst in a first hydrocracker reaction system to convert at least a portion of the hydrocarbons in the mixed gas oil stream to distillate hydrocarbons;
recovering an effluent from the first hydrocracker reaction system comprising unconverted hydrocarbons and the distillate hydrocarbons;
fractionating the effluent from the first hydrocracker reaction system into one or more hydrocarbon fractions including a fraction comprising the unconverted hydrocarbons;
contacting hydrogen and the fraction comprising the unconverted hydrocarbons with a second hydroconversion catalyst in a second hydrocracker reaction system downstream from the first hydrocracker reaction system to convert at least a portion of the unconverted hydrocarbons to distillate hydrocarbons;
feeding the effluent from the second hydrocracker reaction system to the fractionating step for concurrent fractionation with the effluent from the first hydrocracker reaction system;
feeding a stream consisting of the second portion of the first as oil stream to a third hydrocracker reaction system;
contacting a stream consisting of hydrogen and the second portion of the first gas oil stream with a third hydroconversion catalyst in the third hydrocracker reaction system to convert at least a portion of the hydrocarbons in the second portion to distillate hydrocarbons;
fractionating an effluent from the third hydrocracker reaction system to recover two or more hydrocarbon fractions,
wherein the first gas oil stream is different than the second gas oil stream.

2. The process of claim 1 , wherein the first gas oil stream comprises gas oils derived from one or more of petroleum crudes, shale oils, tar sands bitumen, coal-derived oils, tall oils, black oils, and bio-oils and having an atmospheric equivalent, initial boiling point of about 650-680 F based on ASTM method D1160 or equivalent, and wherein the second gas oil stream comprises gas oils produced from thermal or catalytic cracking of heavy oils and having an initial boiling point of about 650-680 F based on ASTM method D1160 or equivalent.

3. The process of claim 2 , wherein the second gas oil stream comprises gas oils produced by at least one of delayed coking, fluid coking, visbreaking, steam cracking, and fluid catalytic cracking.

4. The process of claim 1 , wherein the second gas oil stream is blended with the first gas oil stream in a ratio of at least 0.10 kg of said second gas oil stream per kg first gas oil stream but not more than about 0.90 kg of said second gas oil stream per kg first gas oil stream.

5. The process of claim 1 , wherein the second gas oil stream is blended with the first gas oil stream in a ratio of at least 0.65 kg of said second gas oil stream per kg first gas oil stream but not more than about 0.90 kg of said second gas oil stream per kg first gas oil stream.

6. The process of claim 1 , wherein the second gas oil stream is blended with the first gas oil stream in a ratio of at least 0.8 kg of said second gas oil stream per kg first gas oil stream but not more than about 0.90 kg of said second gas oil stream per kg first gas oil stream.

7. The process of claim 1 , wherein fractionating the effluent from the first and second hydrocracker reaction systems comprises:
feeding the effluents from the first and second hydrocracker reaction systems to a vapor-liquid separator to recover a vapor fraction and a liquid fraction;
fractionating the liquid fraction into the one or more hydrocarbon fractions including a fraction comprising the unconverted hydrocarbons.

8. The process of claim 7 , wherein at least a portion of the vapor fraction is recycled to one or more of the first hydrocracker reaction system, the second hydrocracker reaction system, the third hydrocracker reaction system, and a distillate hydrotreating system.

9. The process of claim 1 , wherein the effluent from the third hydrocracker reaction system is fractionated in a common fractionation system with the effluents from the first and second hydrocracker reaction systems.

10. The process of claim 1 , further comprising:
hydrotreating a hydrocarbon feedstock in a diesel hydrotreating unit;
recovering an effluent from the diesel hydrotreating unit;
feeding the effluent from the diesel hydrotreating unit to the fractionating step for concurrent fractionation with the effluent from the third hydrocracker reaction system.

11. The process of claim 1 , wherein the fractionating the effluent from the third hydrocracker reaction system comprises fractionating the effluent into a C4-fraction, a light naphtha fraction, a heavy naphtha fraction, a kerosene fraction, a diesel fraction, and a base oil fraction.

12. The process of claim 11 , further comprising feeding at least a portion of the base oil fraction to the second hydrocracker reaction system.

13. The process of claim 1 , further comprising:
operating the first hydrocracker reactor system to achieve at least 30% conversion;
operating the second hydrocracker reactor system to achieve at least 45% conversion; and
operating the third hydrocracker reactor system to achieve at least 50% conversion,
wherein conversion is defined as the hydrocracking of hydrocarbon materials boiling above about 650° F. to hydrocarbon materials boiling below about 650° F., both temperatures as defined by ASTM D 1160 or equivalent distillation method.

14. The process of claim 13 ,
wherein the reaction severity for the first hydrocracker reaction system is at least about 35,000° F.-Bara-Hr but no more than about 225,000° F.-Bara-Hr;
wherein the reaction severity for the second hydrocracker reaction system is at least about 25,000° F.-Bara-Hr but no more than about 110,000° F.-Bara-Hr; and
wherein the reaction severity for the third hydrocracker reaction system is at least about 50,000° F.-Bara-Hr but no more than about 235,000° F.-Bara-Hr,
wherein reaction severity is defined as the catalyst average temperature in degrees Fahrenheit of the catalysts loaded in the hydrocracking reactors of a hydrocracking reactor system multiplied by the average hydrogen partial pressure of said hydrocracking reactors in Bar absolute and divided by the liquid hourly space velocity in said hydrocracking reactors.

15. The process of claim 1 , wherein:
the first hydrocracker reaction system is operated at a temperature in the range from about 710° F. to about 750° F.;
the second hydrocracker reaction system is operated at a temperature in the range from about 650° F. to about 690° F.; and
the third hydrocracker reaction system is operated at a temperature in the range from about 710° F. to about 760′F.

16. The process of claim 15 , wherein:
the first hydrocracker reaction system is operated at a liquid hourly space velocity in the range from about 0.5 h −1 to about 0.8 h −1 ;
the second hydrocracker reaction system is operated at a liquid hourly space velocity in the range from about 1.0 h −1 to about 1.5 h −1 ; and
the third hydrocracker reaction system is operated at a liquid hourly space velocity in the range from about 0.5 h −1 to about 0.9 h −1 .

17. The process of claim 1 , wherein the second hydrocracker reaction system is operated at a lower severity than the firs

Assignees

• Lummus Technology Inc

Inventors

• Arora Arun
• Mukherjee Ujjal K
• Louie Wai Seung
• Greene Marvin I

Classifications

• C10L1/04

  essentially based on blends of hydrocarbons · CPC title

• C10L1/14

  Organic compounds · CPC title

• C10G2400/02

  Gasoline · CPC title

• C10G65/12

  including cracking steps and other hydrotreatment steps · CPC title

• C10G65/18

  including only cracking steps · CPC title