Predicting high temperature asphaltene precipitation

Patent metadata

Field	Value
Publication number	US-10344229-B2
Application number	US-201615239034-A
Country	US
Kind code	B2
Filing date	Aug 17, 2016
Priority date	Sep 1, 2015
Publication date	Jul 9, 2019
Grant date	Jul 9, 2019

Abstract

A method for determining a relationship between the ratio of solvent power to critical solvent power and the threshold light paraffin content of a hydrocarbon fluid is provided. The method comprises:
dividing the plurality of hydrocarbon fluids into subgroups, based on the ratio of solvent power to critical solvent power; for each of the subgroups, determining the threshold light paraffin content, said threshold light paraffin content being the light paraffin content of the hydrocarbon fluids at the point at which the fouling tendency of the hydrocarbon fluids exceeds a fouling threshold; and determining a relationship between the ratio of solvent power to critical solvent power and the threshold light paraffin content.

First claim

The invention claimed is:

1. A method for reducing the precipitation of asphaltene from a hydrocarbon fluid in a refinery, said method comprising:
(a) measuring the ratio of solvent power to critical solvent power and the light paraffin content of the hydrocarbon fluid;
(b) based on the light paraffin content of the hydrocarbon fluid, predicting the ratio of solvent power to critical solvent power at which the hydrocarbon fluid will fall below a fouling threshold; and
(c) comparing the ratio measured in step (a) with the ratio predicted in step (b) to determine whether the hydrocarbon fluid will exhibit an acceptable level of fouling; and
(d) feeding the hydrocarbon fluid to the refinery if the ratio of solvent power to critical solvent power is (i) about 1.05 to about 1.1 when the C 1-8 content is less than or equal to 10% or (ii) at least about 1.15 when the C 1-8 content greater than 10% but less than or equal to 20% or (iii) greater than about 1.25 when the C 1-8 content is greater than 25% and, if not, further blending the hydrocarbon fluid with different crude oils together in a refinery to produce a dumb-bell crude blend to increase the ratio of solvent power to critical solvent power.

2. The method of claim 1 , wherein predicting the ratio of solvent power to critical solvent power at which the hydrocarbon fluid will fall below a fouling threshold comprises the steps of:
(a) dividing a plurality of hydrocarbon fluids into subgroups, based on the ratio of solvent power to critical solvent power;
(b) for each of the subgroups, determining threshold light paraffin content said threshold light paraffin content being the light paraffin content of the hydrocarbon fluids at the point at which fouling tendency of the hydrocarbon fluids exceeds a fouling threshold; and
(c) measuring the ratio of solvent power to critical solvent power and the threshold light paraffin content;
(d) predicting the ratio of solvent power to critical solvent power at which the hydrocarbon fluid will fall below a fouling threshold based on the light paraffin content of the hydrocarbon fluid; and
(e) comparing the ratio measured in step (c) with the ratio predicted in step (b) in order to determine whether the hydrocarbon fluid will exhibit an acceptable level of precipitation of asphaltene on the surface of heat exchangers in the refinery.

3. The method of claim 2 , wherein the fluid is divided into at least 3 subgroups.

4. The method of claim 2 , wherein each subgroup contains at least 2 hydrocarbon fluids.

5. The method of claim 2 , wherein each of the subgroups has a size of up to 0.1 ratio units.

6. The method of claim 2 , wherein the method comprises measuring the fouling tendency of the hydrocarbon fluids.

7. The method of claim 6 , wherein the fouling tendency of
the hydrocarbon fluids are determined by carrying out hot liquid process simulator tests.

8. The method of claim 2 , wherein the light paraffin content of the hydrocarbon fluids is taken to be the light distillates content of the hydrocarbon fluid.

9. The method of claim 2 , wherein the light paraffin content of the hydrocarbon fluid is taken to be the c1-4, c1-5, c1-6, c1-7, c1-8, c1-9 or c1-10 paraffin content of the hydrocarbon fluid.

10. The method of claim 2 , wherein the method comprises measuring the solvent power of the hydrocarbon fluids.

11. The method of claim 10 , wherein the solvent power of the hydrocarbon fluids is estimated using characterisation K factor.

12. The method of claim 2 , wherein the method comprises measuring the critical solvent power of the plurality of hydrocarbon fluids.

13. The method of claim 12 , wherein the critical solvent power of the hydrocarbon fluids is measured by titrating the hydrocarbon fluids against a precipitant.

14. The method of claim 2 , wherein the hydrocarbon fluids are crude oils or blends of crude oils.

15. The method of claim 14 , wherein the blends of crude oil are blends of a relatively heavy crude oil and a relatively light crude oil.

16. The method of claim 1 , wherein the precipitation of asphaltene is reduced on the surface of heat exchangers in the refinery.

Assignees

• Bp Corp North America Inc

Inventors

• Balashanmugam Soban
• Fisher Ronald
• Halliday Devin

Classifications

• G01N17/008

  Monitoring fouling · CPC title

• G01N33/2823

  Raw oil, drilling fluid or polyphasic mixtures · CPC title

• C10G75/04 Primary

  by addition of antifouling agents · CPC title

• C10G75/00

  Inhibiting corrosion or fouling in apparatus for treatment or conversion of hydrocarbon oils, in general (C10G7/10, C10G9/16 take precedence) · CPC title

• G01N33/26

  Oils; Viscous liquids; Paints; Inks (G01N33/22 takes precedence) · CPC title