Selective heavy gas oil recycle for optimal integration of heavy oil conversion and vacuum gas oil treating

• US 20090288984A1
• Filed: 05/20/2008
• Published: 11/26/2009
• Est. Priority Date: 05/20/2008
• Status: Active Grant

• Current Assignee: James J. Colyar, John Duddy
• Original Assignee: James J. Colyar, John Duddy
• Inventors: Colyar, James J., Duddy, John
• Granted Patent: US 7,938,953 B2
• Time in Patent Office: Days
• US Class Current: 208/49
• CPC Class Codes: C10G 11/16 according to the "moving bed" method
• CPC Class Codes: C10G 2300/107 Atmospheric residues having a boiling point of at least about 538 °C
• CPC Class Codes: C10G 2300/1074 Vacuum distillates
• CPC Class Codes: C10G 2300/1077 Vacuum residues
• CPC Class Codes: C10G 2300/301 Boiling range
• CPC Class Codes: C10G 2300/4081 Recycling aspects
• CPC Class Codes: C10G 47/00 Cracking of hydrocarbon oils, in the presence of hydrogen or hydrogen- generating compounds, to obtain lower boiling fractions C10G15/00 takes precedence; destructive hydrogenation of non-melting solid carbonaceous or similar materials C10G1/06
• CPC Class Codes: C10G 65/10 including only cracking steps
• CPC Class Codes: C10G 65/12 including cracking steps and other hydrotreatment steps
• CPC Class Codes: C10G 65/14 plural parallel stages only

Abstract

An improved process for heavy oil conversion and upgrading and a combined method for heavy oil conversion and vacuum gas-oil treatment are described herein. The method utilizes the creation and recycle of a separate product from the vacuum still, which is thereafter recycled back to the heavy oil conversion reactor. The result is the production of a higher quality medium gas oil product relative to the overall vacuum gas oil product which is acceptable for use in a typical vacuum gas oil treatment process. Additionally, there is a higher diesel yield selectivity from the heavy oil conversion unit.

Claims

1. A process of heavy vacuum residue conversion and vacuum gas oil treating wherein vacuum residue feedstock is first processed through a heavy oil conversion unit said process comprising:

vacuum separation of the effluent from said conversion unit to obtain a heavy, heavy vacuum gas oil (HHVGO) stream, said HHVGO stream having greater than 90% wt boiling in the 840-1050°

F. range, a fraction of which is thereafter recycled back to the heavy oil conversion unit.

2. A process according to claim 1 wherein the vacuum separation creates a light vacuum gasoil (LVGO) stream in which 90-100% wt below 1000°

F., a medium vacuum gasoil (MVGO) stream, and vacuum bottoms stream, and wherein

at least a fraction of said LVGO and said MVGO is thereafter hydrotreated.

4. The process of claim 2 wherein at least a fraction of said vacuum bottoms stream is thereafter recycled to the heavy oil conversion unit.

3. A process for atmospheric or vacuum residue conversion comprising:

a) providing atmospheric or vacuum residue to a heavy oil conversion reactor, at least 40% of said atmospheric or vacuum residue boiling above 1000°

F. and said reactor operating at reaction conditions of 750°

-850°

F. temperature, 0.10 to 3.0 weight hourly space velocity, and 1000-3000 PSIA inlet hydrogen partial pressure and separating the effluent in a full-range (C₅₊) converted effluent and an unconverted residue effluent (boiling above 650°

F.);

b) passing said unconverted residue to a vacuum still to separate said unconverted residue into vacuum gas oil streams comprising a light vacuum gas oil stream (LVGO), a medium vacuum gas oil stream (MVGO), a heavy, heavy vacuum gas oil stream (HHVGO) boiling between 850°

-1050°

F., and a vacuum residue stream (1050°

F.+);

c) hydrotreating or hydrocracking said light vacuum gas oil stream and medium vacuum gas oil stream;

d) recycling at least a portion of said HHVGO stream along with optional unconverted vacuum residue stream to said heavy oil conversion reactor; and

e) wherein said recycle of the HHVGO results in a higher yield selectivity from the heavy oil conversion and a greatly improved feedstock quality to said hydrotreater or hydrocracker, regarding to the same process without recycle of the HHVGO.