Process for the preparation of a feedstock for a hydroprocessing unit

Abstract

A process for preparing a feedstock for a hydroprocessing unit, the feedstock based on crude oil containing asphaltenes and the process including mixing crude oil with a predetermined solvent in a ratio such that no aggregation of asphaltenes in the mixture takes place, and feeding the combined mixture to one or more hydroprocessing units.

Claims

1. A process for the preparation of a feedstock for a hydroprocessing unit, wherein said feedstock is based on crude oil containing asphaltenes, said process comprising the steps of: mixing said crude oil with a solvent, wherein said solvent includes at least one of steam cracker cracked distillate (CD), steam cracker carbon black oil (CBO), low asphaltenes containing crude oil residue having a boiling point above 300 C. deg C. and aromatic rich hydrocarbons streams, wherein a mixing ratio of said solvent to said crude oil is such that no aggregation of asphaltenes in said combined mixture of solvent and crude oil takes place under mixing conditions; and feeding said combined mixture of solvent and crude oil to one or more hydroprocessing units, wherein said combined mixture of solvent and crude oil comprises 25 wt. % or more of cracked distillate, based on the total weight of the feed blend.

2. A process for the preparation of a feedstock for a hydroprocessing unit, wherein said feedstock is based on crude oil containing asphaltenes, said process comprising the steps of: mixing said crude oil with a solvent, wherein said solvent includes at least one of steam cracker cracked distillate (CD), steam cracker carbon black oil (CBO), low asphaltenes containing crude oil residue having a boiling point above 300 C. deg C. and aromatic rich hydrocarbons streams, wherein a mixing ratio of said solvent to said crude oil is such that no aggregation of asphaltenes in said combined mixture of solvent and crude oil takes place under mixing conditions; and feeding said combined mixture of solvent and crude oil to one or more hydroprocessing units, wherein said combined mixture of solvent and crude oil comprises a maximum of 55 wt. % of the higher asphaltenes containing crude stream in combination with the lower asphaltenes containing crude oils and aromatic streams.

3. The process according to claim 1, wherein said combined mixture of solvent and crude oil prior to entering the one or more hydroprocessing units, or its feed heaters, has an S value, measured as per ASTMD7157-12, of greater than 1.

4. The process according to claim 1, wherein said crude oil is a bottom stream from a vacuum distillation unit.

5. The process according to claim 1, further comprising deasphalting said crude oil, and separating the crude oil thus deasphalted in a stream having a low content of asphaltenes and a stream having a high content of asphaltenes, wherein said stream having a high content of asphaltenes is mixed with said solvent.

6. The process according to claim 1, wherein said one or more hydroprocessing units are chosen from the group of a resid hydrocracking unit and a coking unit.

7. The process according to claim 2, wherein said combined mixture of solvent and crude oil prior to entering the one or more hydroprocessing units, or its feed heaters, has an S value, measured as per ASTMD7157-12, of greater than 1.

8. The process according to claim 2, wherein said crude oil is a bottom stream from a vacuum distillation unit.

9. The process according to claim 2, further comprising deasphalting said crude oil, and separating the crude oil thus deasphalted in a stream having a low content of asphaltenes and a stream having a high content of asphaltenes, wherein said stream having a high content of asphaltenes is mixed with said solvent.

10. The process according to claim 2, wherein said one or more hydroprocessing units are chosen from the group of a resid hydrocracking unit and a coking unit.

11. The process according to claim 1, wherein said combined mixture of solvent and crude oil comprises more than 25 wt. % of low asphaltenes containing crude oil, atmospheric or vacuum residue, based on the total weight of the feed blend.

12. The process according to claim 2, wherein said combined mixture of solvent and crude oil comprises more than 25 wt. % of low asphaltenes containing crude oil, atmospheric or vacuum residue, based on the total weight of the feed blend.

13. The process according to claim 4, wherein said combined mixture of solvent and crude oil prior to entering the one or more hydroprocessing units, or its feed heaters, has an S value, measured as per ASTMD7157-12, of greater than 1.

14. The process according to claim 5, wherein said crude oil is a bottom stream from a crude oil distillation unit (CDU).

15. The process according to claim 8, further comprising deasphalting said crude oil, and separating the crude oil thus deasphalted in a stream having a low content of asphaltenes and a stream having a high content of asphaltenes, wherein said stream having a high content of asphaltenes is mixed with said solvent.

16. The process according to claim 3, wherein said one or more hydroprocessing units are chosen from the group of a resid hydrocracking unit and a coking unit.

17. The process according to claim 9, wherein said crude oil is a bottom stream from a vacuum distillation unit (VDU).

18. The process according to claim 17, wherein said combined mixture of solvent and crude oil comprises more than 25 wt. % of low asphaltenes containing crude oil, atmospheric or vacuum residue, based on the total weight of the feed blend.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention will be described in further detail below and in conjunction with the attached drawing.

(2) FIG. 1 is a schematic illustration of an embodiment of the process of the invention.

(3) FIG. 2 is a schematic illustration of an embodiment of the process of the invention.

DETAILED DESCRIPTION OF THE INVENTION

(4) Referring now to the process and apparatus 1 schematically depicted in FIG. 1, there is shown a crude distillation unit 3 from which its bottom stream is sent to a vacuum distillation unit (VDU) 4. The effluent from the vacuum distillation unit 4 is sent tot a solvent dissolution unit 7. In solvent dissolution unit 7 the effluent coming directly from VDU 4 is mixed with a solvent 6. Solvent 6 is chosen from the group of steam cracker cracked distillate (CD), steam cracker carbon black oil (CBO), low asphaltenes containing crude oil residue having a boiling point above 300 deg C. and aromatic rich hydrocarbons streams.

(5) According to another embodiment an additional stream 2, e.g. the effluent from a crude or distillation unit (CDU), is also fed to solvent dissolution unit 7 and mixed with solvent 6 and the effluent coming from VDU 4. By mixing the atmospheric residue or vacuum residue with a specific type of solvent the aggregation of asphaltenes in the mixture thus obtained is significantly reduced. Also the sulphur loading of the mixed stream 15 is lower than the sulphur loading of an untreated effluent coming from VDU 4 and/or CDU 2.

(6) Mixed stream 15, i.e. the effluent from the solvent dissolution unit 7, and hydrogen 8 are further processed in hydroprocessing units 13, for example hydrodesulphurisation, producing individual streams 9, mainly comprising ammonia, stream 10, mainly comprising H2S, stream 11, mainly comprising C2.sup. and stream 13, mainly comprising C3+C4. The effluent from hydroprocessing unit 13 is sent to another hydroprocessing unit 14, for example a resid hydrocracker, a FCC unit or a coker unit.

(7) By mixing solvent 6 with atmospheric residue and/or a vacuum residue the viscosity of feed 15 is significantly reduced. In addition, not only the viscosity of feed 15 is significantly reduced but the metal content of feed 15 is also significantly reduced. Another possible benefit of the mixing step with solvent is that the hydrogen content of feed 16 may be improved.

(8) FIG. 2 is a schematic illustration of another embodiment of the process of the invention. The essential difference between the process shown in FIG. 1 and FIG. 2 is the presence of a deasphalting unit 5 located between vacuum distillation unit 4 and solvent dissolution unit 7. In deasphalting unit 5 the effluent from vacuum distillation unit 4 is brought into contact with a solvent stream 17, resulting in a stream 18, i.e. a stream having low content asphaltenes, and a stream 19, i.e. a stream having a high content asphaltenes. Stream 19 is sent to solvent dissolution unit 7 and mixed with solvent 6, i.e. steam cracker cracked distillate (CD) and/or steam cracker carbon black oil (CBO) and/or low asphaltenes containing crude oil residue having a boiling point above 300 deg C. and/or aromatic rich hydrocarbons streams.

(9) The attached Figures and examples represent alternative embodiments of the overall invention. The Figures and examples pertaining to the invention are intended to be viewed as exemplary embodiments within the scope of the overall invention as claimed.

Example 1

(10) The Saturates, aromatics, resins and asphaltenes (SARA) analysis of cracked distillate (CD) from steam cracker is 7.76/92.24/0/0. The 340+ deg C. residue (AHAR) from Arab heavy crude oil has the SARA analysis 53.7/34.8/3.1/8.1. The combination of these streams in different weight proportions is analysed in the below table and the predicted stable asphaltenes concentration for these combinations is presented below.

(11) TABLE-US-00001 75% AHAR + 50% AHAR + 25% AHAR + 100% AHAR 25% CD 50% CD 75% CD 100% CD Asphaltenes 8.1 6.08 4.05 2.03 0 Saturates 53.7 42.21 30.73 19.24 7.76 Aromatics 34.8 49.16 63.52 77.88 92.24 Resins 3.1 2.33 1.55 0.78 0.00 Predicted stable 4.56 6.61 8.66 10.71 12.77 Asphaltene concentration in mixture from aromatics and resins concentration in mixture

(12) As can be seen from the table, stable asphaltenes combinations can be obtained in the mixture of AHAR with CD in all proportions exceeding 25 wt % CD in the mixture.

Example 2

(13) The Saturates, aromatics, resins and asphaltenes (SARA) analysis of Arab light 340+ deg C. cut (ALAR) is 61.8/30.5/3.4/3.5. The 340+ deg C. residue (AHAR) from Arab heavy crude oil has the SARA analysis 53.7/34.8/3.1/8.1. The combination of these streams in different weight proportions is analysed in the below table and the predicted stable asphaltenes concentration for these combinations based on the concentration of resins and aromatics in the combined mixture is presented.

(14) TABLE-US-00002 75% 50% 25% AHAR + AHAR + AHAR + 100% 25% 50% 75% 100% AHAR ALAR ALAR ALAR ALAR Asphaltenes 8.1 6.95 5.80 4.65 3.5 Saturates 53.7 55.73 57.75 59.78 61.8 Aromatics 34.8 33.73 32.65 31.58 30.5 Resins 3.1 3.18 3.25 3.33 3.4 Predicted stable 4.56 4.40 4.25 4.10 3.95 Asphaltene concentration in mixture from aromatics and resins concentration in mixture

(15) As can be seen from the table, stable asphaltenes combinations can be obtained in the mixture of AHAR and ALAR when ALAR concentration in the mixture is above 75 wt %.

Example 3

(16) Aijun Guo et al, Fuel processing technology 89 (2008) 643-650 provide the Saturates, aromatics, resins and asphaltenes (SARA) analysis of Jinzhou vacuum residue (JnVR) as 17.2/29.6/51.3/1.9. The 340+ deg C. residue (AHAR) from Arab heavy crude oil has the SARA analysis 53.7/34.8/3.1/8.1. The combination of these streams in different weight proportions is analysed in the below table.

(17) TABLE-US-00003 75% 50% 25% 100% AHAR + AHAR + AHAR + 100% AHAR 25% JnVR 50% JnVR 75% JnVR JnVR Asphaltenes 8.1 6.55 5.00 3.45 1.9 Saturates 53.7 44.58 35.45 26.33 17.20 Aromatics 34.8 33.50 32.20 30.90 29.60 Resins 3.1 15.15 27.20 39.25 51.30 Predicted stable 4.56 6.18 7.80 9.43 11.05 Asphaltene concentration in mixture from aromatics and resins concentration in mixture

(18) As can be seen from the above table, asphaltenes are stable in the mixture containing more than 25 wt % JnVR. This example has been provided as it has a different distribution of resins as compared to example 1. Operating refineries that process a crude basket having asphaltenes-rich and asphaltenes-lean crudes and have different crude units for these different crude types can benefit from a combination of residues from asphaltenes-rich and asphaltenes-lean crude oils and process them together in a hydrocracking unit.

Example 4

(19) The Saturates, aromatics, resins and asphaltenes (SARA) analysis of Arab light 340+ deg C. cut (ALAR) is 61.8/30.5/3.4/3.5. The 340+ deg C. residue (AHAR) from Arab heavy crude oil has the SARA analysis 53.7/34.8/3.1/8.1. The Saturates, aromatics, resins and asphaltenes (SARA) analysis of cracked distillate (CD) from steam cracker is 7.76/92.24/0/0. The combination of these streams in different weight proportions is analysed in the below table.

(20) TABLE-US-00004 75% 55% 40% AHAR + AHAR + AHAR + 15% 25% 40% 100% ALAR + 10% ALAR + 20% ALAR + 20% 100% AHAR CD CD CD ALAR 100% CD Asphaltenes 8.1 6.60 5.33 2.64 3.5 0 Saturates 53.7 50.32 46.54 23.23 61.8 7.76 Aromatics 34.8 39.90 45.21 52.86 30.5 92.24 Resins 3.1 2.84 2.56 1.13 3.4 0.00 Predicted 4.56 5.29 6.05 6.99 3.95 12.77 stable Asphaltene concentration in mixture from aromatics and resins concentration in mixture

(21) As can be seen from the above table with certain combinations of AHAR, ALAR and CD it is possible to keep asphaltenes from precipitating out.