Heavy oil conversion

Abstract

A method of converting heavy oil into one or more valuable products comprises hydroconverting heavy oil, recovering an effluent stream from the hydroconverting, and deep catalytic cracking the effluent stream. The hydroconverting comprises reacting a slurry comprising unsupported fine catalyst in heavy oil. The effluent stream comprises unsupported fine catalyst in unconverted heavy oil. The deep catalytic cracking converts unconverted heavy oil into one or more light oil products.

Description

BACKGROUND

As light oil reserves are gradually being depleted and the costs of development (e.g., lifting, mining, and extraction) of heavy oil resources have decreased, a need has arisen to develop novel upgrading technologies to convert heavy oils and bitumens into lighter products. The “bottom of the barrel”, or high boiling range material (i.e., vacuum residue) from crude oil, is difficult to convert into lighter products via conventional processes. Thus, what is needed are new technologies that achieve conversion of vacuum residue, which would offer significant promise in resolving the problems associated with the disposition of large amounts of vacuum residue.

SUMMARY

Provided is a method of converting heavy oil into one or more valuable products. The method comprises hydroconverting heavy oil, recovering an effluent stream from the hydroconverting, and deep catalytic cracking the effluent stream. The hydroconverting comprises reacting a slurry comprising unsupported fine catalyst in heavy oil. The effluent stream comprises unsupported fine catalyst in unconverted heavy oil. The deep catalytic cracking converts unconverted heavy oil into one or more light oil products.

DETAILED DESCRIPTION

As used herein, “heavy oil” refers to an oil characterized by low hydrogen to carbon ratios and high carbon residues, asphaltenes, nitrogen, sulfur and metal contents. Examples include atmospheric gas oils, vacuum gas oils, deasphalted oils, olefins, oils derived from tar sands or bitumen, oils derived from coal, heavy crude oils, synthetic oils from Fischer-Tropsch processes, and oils derived from recycled oil wastes and polymers.

The presently claimed method of converting heavy oil into one or more valuable products comprises hydroconverting heavy oil, recovering an effluent stream from the hydroconverting, and deep catalytic cracking the effluent stream. The hydroconverting comprises reacting a slurry comprising unsupported fine catalyst in heavy oil. The effluent stream comprises unsupported fine catalyst in unconverted heavy oil. The deep catalytic cracking converts unconverted heavy oil into one or more light oil products.

As used herein, the phrases “light oil” and “light oil products” refer to hydrocarbons or hydrocarbon mixtures (e.g., products of heavy oil upgrading) which boil below 700° F. (i.e., which have boiling ranges below that of a lubricant). For example, U.S. Pat. No. 6,841,062 explains that the term “light gas oil” (LGO) can to be taken as a reference to hydrocarbons or hydrocarbon mixtures which can be isolated as distillate streams obtained during the conventional atmospheric distillation of a refinery stream, a petroleum stream or a crude oil stream.

Catalyst Slurry

The presently described method utilizes catalysts in the conversion (in particular, hydroconversion) of heavy oil (i.e., reaction of a slurry comprising unsupported fine catalyst in heavy oil) into one or more light oil products. In an embodiment, the catalysts are composed predominantly of compounds such as a Group VI and/or Group VIII metal compound sulfide, for example, molybdenum sulfide (MoS₂) and nickel sulfide (NiS), as described in U.S. Pat. No. 5,484,755 and U.S. Patent Application Publication Nos. 2006/0054534 A1, 2006/0054535 A1, 2006/0058174 A1, and 2006/0058175 A1, the contents of which are hereby incorporated by reference in their entireties. The highly active, unsupported catalysts typically exhibit particle size distributions in the range of about 1-8 microns, with some smaller and larger particles existing on either end of the range. In particular, the catalyst particles can have a size distribution in the range of about 0.2-20 microns, and a mean particle size of about 4-5 micron, with the mode being about 6-7 micron.

Heavy Oil Upgrading

Suitable feeds to a process for upgrading heavy oils using the slurry catalyst composition, include, for example, atmospheric residuum, vacuum residuum, tar from a solvent deasphlating unit, atmospheric gas oils, vacuum gas oils, deasphalted oils, olefins, oils derived from tar sands or bitumen, oils derived from coal, heavy crude oils, synthetic oils from Fischer-Tropsch processes, and oils derived from recycled oil wastes and polymers. The feed is supplied to a reactor, wherein the feed is reacted with the catalyst slurry described in further detail below and hydrogen. In an embodiment, the reactor is a liquid recirculating reactor, although other types of upflow reactors may be employed. The catalyst slurry can be useful for, but not limited to, hydrogenation upgrading processes such as thermal hydrocracking, hydrotreating, hydrodesulphurization, hydrodenitrification, and hydrodemetalization.

The temperature of the reaction zone generally ranges from about 300° F. to about 600° F., for example, from about 350° F. to about 500° F. or from about 350° F. to about 450° F. The pressure of the reaction zone generally ranges from about 100 psig to about 3000 psig, for example, from about 200 psig to about 1000 psig or from about 300 psig to about 500 psig. The hydrogen flow to the reaction zone generally ranges from about 300 SCFB to about 2000 SCFB, for example, from about 300 SCFB to about 1000 SCFB or from about 300 SCFB to about 500 SCFB. The reaction time in the reaction zone ranges from about 10 minutes to 5 hours, for example, from 30 minutes to 3 hours or from about 1 hour to 1.5 hours. The resultant slurry mixture is the active catalyst composition in admixture with the hydrocarbon oil. The heavy oil upgrading can comprise conditions, for example, as described in U.S. Patent Application Publication Nos. 2006/0054534 A1, 2006/0054535 A1, 2007/0138055 A1, and 2007/0138057 A1, the contents of which are hereby incorporated by reference in their entireties.

Processing of an effluent stream containing unsupported catalyst in unconverted feed is described herein. The effluent stream containing unsupported catalyst is primarily made-up of finely divided unsupported slurry catalyst, carbon fines, and metal fines in unconverted resid hydrocarbon oil. The effluent stream can comprise less than about 25 volume %, for example, less than about 10 volume % or less than about 5 volume %, of the feed to the heavy oil upgrading.

Processing of the effluent stream containing unconverted feed allows for greater conversion of the feed (e.g., heavy oils, vacuum residue, bitumen, etc.) into lighter products. In particular, the deep catalytic cracking converts into lighter products unconverted material in the feed, which otherwise would remain unconverted. Additionally, the deep catalytic cracking utilizes active catalyst in the effluent stream, rather than requiring separation of the active catalyst from the effluent stream or recycle of the active catalyst in the effluent stream to the heavy oil upgrading. Further, as the effluent stream to the deep catalytic cracking comprises less than about 25 volume %, for example, less than about 10 volume % or less than about 5 volume %, of the feed to the heavy oil upgrading, the deep catalyst cracking reactor can be much smaller than the heavy oil upgrading reactor.

Deep Catalytic Cracking

As described above with regard to the heavy oil upgrading, the deep catalytic cracking reactor can be a liquid recirculating reactor, although other types of upflow reactors may be employed. Similar to the heavy oil upgrading, the deep catalytic cracking can comprise, for example, hydrogenation upgrading processes such as thermal hydrocracking, hydrotreating, hydrodesulphurization, hydrodenitrification, and hydrodemetalization.

According to the presently claimed method, the finely divided unsupported slurry catalyst needs to still be active for hydrogen addition. Similar to the heavy oil upgrading described above, the temperature of the deep catalytic cracking zone generally ranges from about 300° F. to about 600° F., for example, from about 350° F. to about 500° F. or from about 350° F. to about 450° F.; the pressure of the deep catalytic cracking zone generally ranges from about 100 psig to about 3000 psig, for example, from about 200 psig to about 1000 psig or from about 300 psig to about 500 psig; the hydrogen flow to the deep catalytic cracking zone generally ranges from about 300 SCFB to about 2000 SCFB, for example, from about 300 SCFB to about 1000 SCFB or from about 300 SCFB to about 500 SCFB; and the reaction time in the deep catalytic cracking zone ranges from about 10 minutes to 5 hours, for example, from 30 minutes to 3 hours or from about 1 hour to 1.5 hours. The deep catalytic cracking can comprise conditions, for example, as described in U.S. Patent Application Publication Nos. 2006/0054534 A1, 2006/0054535 A1, 2007/0138055 A1, and 2007/0138057 A1, the contents of which are hereby incorporated by reference in their entireties.

The system could be operated as a continuous system or a batch system by integrating the deoiling process with the heavy oil upgrading reactor. In particular, the effluent from the heavy oil upgrading reactor can be sent directly to one of at least two batch reactors for collecting and then deep cracking for a continuous flow system. The system pressure does not change. After deep cracking, the slurry can be sent to another low pressure vessel for drying, and the light oil formed can be mixed with all other light oils, eliminating the need for another distillation system for the deoiling process. The unit can be depressurized and the catalyst dried in the same reactor.

Effluent streams from the upgrading reactor and deep catalytic cracking reactor, following downstream processing, such as, for example, separation(s), can include one or more valuable light oil products as well as a stream containing unsupported catalyst in unconverted feed. Such separations can comprise methods described in U.S. application Ser. Nos. ______ (T-6553) and ______ (T-6554), the contents of which are hereby incorporated by reference in their entireties, filed concurrently herewith.

Many modifications of the exemplary embodiments disclosed herein will readily occur to those of skill in the art. Accordingly, the present disclosure is to be construed as including all structure and methods that fall within the scope of the appended claims.

Claims

1. A method of converting heavy oil into one or more valuable products, the method comprising:

hydroconverting heavy oil, wherein the hydroconverting comprises reacting a slurry comprising unsupported fine catalyst in heavy oil;

recovering an effluent stream from the hydroconverting, wherein the effluent stream comprises unsupported fine catalyst in unconverted heavy oil; and

deep catalytic cracking the effluent stream, wherein the deep catalytic cracking converts unconverted heavy oil into one or more light oil products.

2. The method of claim 1, wherein the catalyst comprises particles having a size distribution in the range of about 0.2 to about 20 microns and a mean particle size in the range of about 4 to about 5 micron, wherein a mode of the size distribution is in the range of about 6 to about 7 micron.

3. The method of claim 1, wherein the catalyst comprises a Group VI and/or Group VIII metal compound sulfide.

4. The method of claim 1, wherein at least a portion of the slurry comprising unsupported fine catalyst in heavy oil comprises a product of an ebulating bed reactor.

5. The method of claim 1, wherein the deep catalytic cracking is conducted at a temperature of about 300° F. to about 600° F.

6. The method of claim 1, wherein the deep catalytic cracking is conducted at a residence time of about 10 minutes to 5 hours.

7. The method of claim 1, wherein the deep catalytic cracking is conducted at a pressure of about 100 psig to about 3000 psig.

8. The method of claim 1, wherein the deep catalytic cracking comprises hydrogen flow of about 300 SCFB to about 2000 SCFB.

9. The method of claim 1, wherein the deep catalytic cracking comprises a batch system.

10. The method of claim 1, wherein the deep catalytic cracking comprises a continuous system.

11. The method of claim 1, further comprising separating unsupported fine catalyst from the one or more light oil products.

12. The method of claim 1, wherein the separating comprises drying the catalyst.

13. The method of claim 12, wherein the deep catalytic cracking is conducted in a reactor and the drying is conducted in the same reactor as the deep catalytic cracking.

14. The method of claim 12, further comprising depressurizing the reactor after the deep catalytic cracking and prior to the drying.

15. The method of claim 1, wherein the separating comprises sending the unsupported fine catalyst and the one or more light oil products to a low pressure vessel for drying.

16. The method of claim 15, further comprising mixing the unsupported fine catalyst and the one or more light oil products with one or more additional light oil products prior to drying.

17. The method of claim 1, where the effluent stream comprises less than about 25 volume % of the slurry comprising unsupported fine catalyst in heavy oil.

18. The method of claim 1, where the effluent stream comprises less than about 10 volume % of the slurry comprising unsupported fine catalyst in heavy oil.

19. The method of claim 1, where the effluent stream comprises less than about 5 volume % of the slurry comprising unsupported fine catalyst in heavy oil.