Method to improve the efficiency of pipeline transportation of heavy oils
Disulfide oil (DSO) compounds recovered as a by-product of the mercaptan oxidation of a hydrocarbon refinery feedstock and their oxidized derivatives, oxidized disulfide oils (ODSO) are effective as a diluent to lower the viscosity and thereby improve the pipeline transportation properties of heavy oils, and particularly of wellhead crude oil. The use of the DSO and/or ODSO compounds as diluents converts an otherwise extremely low value or waste oil product into a valuable commodity that has utility in improving the transportation properties of heavy oils, particularly in oil field pipeline applications.
1. A process for reducing the viscosity of a heavy oil feedstream comprising mixing the heavy oil feedstream in at least one mixing zone with a predetermined amount of a liquid hydrocarbon diluent to produce a heavy oil-diluent blend that has a lower density and a lower viscosity than that of the heavy oil feedstream,
wherein the liquid hydrocarbon diluent is one or more oxidized disulfide oil compounds having the general formula:
O x R′SSR
where x is an integer in the range of from 1 to 4, R and R′ are straight, branched or cyclic hydrocarbons having 1, 2, 3 and up to 10 or more carbon atoms that are saturated or unsaturated, and where R and R′ can be the same or different.
2. The process of claim 1 , wherein the heavy oil is selected from crude oil recovered at a wellhead, bitumens, heavy crude oil, coal liquids, atmospheric residue, vacuum residue, pitch from solvent deasphalting, and heavy oil derived from refinery processes such as distillation, solvent deasphalting, delayed coking, or FCC processing.
3. The process of claim 1 , wherein the heavy oil-diluent blend comprises diluent in the range of from 1 to 99 W % of the total weight of the blend.
4. The process of claim 1 , wherein the heavy oil-diluent blend comprises diluent in the range of from 5 to 50 W % of the total weight of the blend.
5. The process of claim 1 , wherein the heavy oil has an initial viscosity of at least 1000 mPa·s at 50° C.
6. The process of claim 1 , wherein the heavy oil has an API gravity of less than or equal to 30°.
7. A process for reducing the viscosity of a heavy oil feedstream for transportation in an oil pipeline, the process comprising:
a. mixing the heavy oil feedstream with a predetermined amount of a fresh liquid hydrocarbon diluent in a mixing zone at a first location to produce a heavy oil-diluent blend that has a lower density and a lower viscosity than the heavy oil feedstream alone,
wherein the fresh diluent stream comprises one or more DSO compounds, one or more ODSO compounds, or their combination, where the DSO and ODSO compounds are derived from the mercaptan oxidation of a refinery feedstream;
b. recovering the heavy oil-diluent blend from the mixing zone as a product stream at the first location;
c. introducing the recovered heavy oil-diluent blend product stream into a first transportation pipeline for transportation to a second location.
8. The process of claim 7 , further comprising the steps of:
d. receiving the heavy oil-diluent blend of step (c) in the second location and introducing the blend into a fractionation zone for separation of the heavy oil from the diluent;
e. recovering the liquid hydrocarbon diluent; and
f. recovering or further processing the heavy oil as a product stream.
9. The process of claim 8 , further comprising the steps of:
g. introducing the diluent recovered in step 14(e) into a second transportation pipeline and returning the diluent to the first location as a recycle diluent stream; and
h. introducing the recycle diluent stream and fresh diluent for mixing with heavy oil to produce the heavy oil-diluent blend.
10. The process of claim 8 , wherein the heavy oil feedstream is further processed in the second location fractionation zone to provide one or more feeds for downstream refinery operations.
11. The process of claim 7 , wherein the heavy oil-diluent blend is free, or substantially free of sediment.
12. The process of claim 7 , in which the heavy oil feedstream is wellhead crude oil.
13. The process of claim 7 , wherein the heavy oil feedstream is selected from crude oil recovered at a wellhead, bitumens, heavy crude oil, coal liquids, atmospheric residue, vacuum residue, pitch from solvent deasphalting, and heavy oil derived from refinery processes such as distillation, solvent deasphalting, delayed coking, or FCC processing.
14. A process for reducing the viscosity of a heavy oil feedstream comprising mixing the heavy oil feedstream in at least one mixing zone with a predetermined amount of a liquid hydrocarbon diluent to produce a heavy oil-diluent blend that has a lower density and a lower viscosity than that of the heavy oil feedstream,
wherein the liquid hydrocarbon diluent is one or more oxidized disulfide oil compounds having the general formula:
O x RSSOH,
where x is 2, 3, or 4 and R can be straight, branched or cyclic hydrocarbons having 1, 2, 3 and up to 10 or more carbon atoms that are saturated or unsaturated.
15. The process of claim 14 , wherein the heavy oil feedstream is selected from crude oil recovered at a wellhead, bitumens, heavy crude oil, coal liquids, atmospheric residue, vacuum residue, pitch from solvent deasphalting, and heavy oil derived from refinery processes such as distillation, solvent deasphalting, delayed coking, or FCC processing.
16. A process for reducing the viscosity of a heavy oil feedstream comprising mixing the heavy oil feedstream in at least one mixing zone with a predetermined amount of a liquid hydrocarbon diluent selected from the group consisting of:
one or more DSO compounds, one or more ODSO compounds, or a combination thereof to produce a heavy oil-diluent blend that has a lower density and a lower viscosity than that of the heavy oil feedstream,
wherein the heavy oil-diluent blend is passed from the at least one mixing zone to a transportation pipeline.
17. The process of claim 16 , wherein the heavy oil-diluent blend has a viscosity of less than or equal to 380 mPa·s under the conditions in the transportation pipeline.
18. The process of claim 17 , wherein the viscosity of the heavy oil-diluent blend is less than 200 mPa·s.
19. The process of claim 16 , wherein the heavy oil-diluent blend passed to the transportation pipeline is at temperatures in the range of from 20° C. to 80° C. and at a pressure in the range of from 1 bar to 5 bars.
20. The process of claim 16 , wherein the heavy oil feedstream is selected from crude oil recovered at a wellhead, bitumens, heavy crude oil, coal liquids, atmospheric residue, vacuum residue, pitch from solvent deasphalting, and heavy oil derived from refinery processes such as distillation, solvent deasphalting, delayed coking, or FCC processing.