Compositions and methods of removing contaminants in refinery desalting
It has been discovered that contaminants such as metals and/or amines can be transferred from a hydrocarbon phase to a water phase in an emulsion breaking process by using a composition that contains water-soluble C5-C12 polyhydroxy carboxylic acids, ammonium salts thereof, alkali metal salts thereof, and mixtures of all of these. The composition may also optionally include a mineral acid to reduce the pH of the desalter wash water. The method permits transfer of metals and/or amines into the aqueous phase with little or no hydrocarbon phase undercarry into the aqueous phase. Resolving the emulsion into the hydrocarbon phase and the aqueous phase occurs in a refinery desalting process using electrostatic coalescence. The composition is particularly useful in treating crude oil emulsions, and in removing calcium and other metals therefrom. The polyhydroxy carboxylic acid additionally inhibits metal corrosion of metal pipe or other equipment used in a crude unit.
1. A treated hydrocarbon emulsion comprising:
crude oil;
water having a pH of 6 or below;
contaminants comprising metal naphthenates; and
a composition in an effective amount to transfer contaminants from a hydrocarbon phase to an aqueous phase, the composition comprising a water-soluble component selected from the group consisting of polyhydroxy carboxylic acids having 5 to 12 carbon atoms selected from the group consisting of glucaric acid, iduronic acid, galacturonic acid, glucuronic acid, digalacturonic acid, and combinations thereof, ammonium salts thereof, alkali metal salts thereof, where the polyhydroxy carboxylic acid has a boiling point in the range of 389 to 559° C. and does not include gluconic acid, and mixtures of any of these.
2. The treated hydrocarbon emulsion of claim 1 where the contaminants comprise one selected from the group consisting of metals, salts, solids other than salts, amines, and combinations thereof.
3. The treated hydrocarbon emulsion of claim 2 where the contaminant is a metal selected from the metals in a Periodic Table Group selected from the group consisting of IA, IIA, IVA, IB, IIB, VB, VIB, and VIII.
4. The treated hydrocarbon emulsion of claim 3 where the metal is selected from the group consisting of calcium, magnesium, iron, zinc, nickel, chromium, lead, cadmium, copper, and combinations thereof.
5. The treated hydrocarbon emulsion of claim 1 where the polyhydroxy carboxylic acid is present in an amount effective to inhibit metal corrosion of metal pipe or other equipment used in a crude unit.
6. The treated hydrocarbon emulsion of claim 5 in an absence of a different added corrosion inhibitor.
7. The treated hydrocarbon emulsion of claim 5 where the polyhydroxy carboxylic acid forms a molar 1:1 salt with the contaminant.
8. The treated hydrocarbon emulsion of claim 1 where the composition additionally comprises a mineral acid in an amount effective to lower the pH of the water to 6 or below.
9. The treated hydrocarbon emulsion of claim 1 where the polyhydroxy carboxylic acid is present in the emulsion in an amount ranging from about 1 to about 2000 ppm, based on the crude oil.
10. A treated hydrocarbon emulsion comprising:
crude oil;
water having a pH of 6 or below;
contaminants comprising metal naphthenates; and
a composition in an effective amount to transfer contaminants from a hydrocarbon phase to an aqueous phase, the composition comprising a water-soluble component selected from the group consisting of polyhydroxy carboxylic acids having 5 to 12 carbon atoms selected from the group consisting of glucaric acid, iduronic acid, galacturonic acid, glucuronic acid, digalacturonic acid, and combinations thereof, ammonium salts thereof, alkali metal salts thereof, where the polyhydroxy carboxylic acid has a boiling point in the range of 389 to 559° C. and does not include gluconic acid, and mixtures of any of these; where the polyhydroxy carboxylic acid is present in an amount effective to additionally inhibit metal corrosion of metal pipe or other equipment used in a crude unit, and where the treated hydrocarbon emulsion additionally has an absence of a different added corrosion inhibitor.
11. The treated hydrocarbon emulsion of claim 10 where the contaminants comprise one selected from the group consisting of metals, salts, solids other than salts, amines, and combinations thereof.
12. The treated hydrocarbon emulsion of claim 11 where the contaminant is a metal selected from the metals in a Periodic Table Group selected from the group consisting of IA, IIA, IVA, IB, IIB, VB, VIB, and VIII.
13. The treated hydrocarbon emulsion of claim 11 where the metal is selected from the group consisting of calcium, magnesium, iron, zinc, nickel, chromium, lead, cadmium, copper, and combinations thereof.
14. The treated hydrocarbon emulsion of claim 10 where the polyhydroxy carboxylic acid forms a molar 1:1 salt with the contaminant.
15. The treated hydrocarbon emulsion of claim 10 where the polyhydroxy carboxylic acid forms a molar 1:1 salt with the contaminant.
16. The treated hydrocarbon emulsion of claim 10 where the composition additionally comprises a mineral acid in an amount effective to lower the pH of the water to 6 or below.
17. A treated hydrocarbon emulsion comprising:
crude oil;
water having a pH of 6 or below;
contaminants selected from the group consisting of metals, salts thereof, iron-based solids, and combinations thereof, where the metal is selected from the group consisting of calcium, magnesium, iron, zinc, nickel, chromium, lead, cadmium, copper, and combinations thereof where the contaminants at least comprise a metal naphthenate; and
a composition in an effective amount to transfer contaminants from a hydrocarbon phase to an aqueous phase, the composition comprising a water-soluble component selected from the group consisting of polyhydroxy carboxylic acids having 5 to 12 carbon atoms selected from the group consisting of glucaric acid, iduronic acid, galacturonic acid, glucuronic acid, digalacturonic acid, and combinations thereof, ammonium salts thereof, alkali metal salts thereof, where the polyhydroxy carboxylic acid has a boiling point in the range of 389 to 559° C. and does not include gluconic acid, and mixtures of any of these, where the polyhydroxy carboxylic acid is present in an amount effective to inhibit metal corrosion of metal pipe or other equipment used in a crude unit, in an absence of a different added corrosion inhibitor, and where the polyhydroxy carboxylic acid forms a molar 1:1 salt with the contaminant.
18. The treated hydrocarbon emulsion of claim 17 where the composition additionally comprises a mineral acid in an amount effective to lower the pH of the water to 6 or below.
19. The treated hydrocarbon emulsion of claim 17 where the polyhydroxy carboxylic acid is present in the emulsion in an amount ranging from about 1 to about 2000 ppm, based on the crude oil.
20. The treated hydrocarbon emulsion of claim 17 where the polyhydroxy carboxylic acid is present in an amount effective to inhibit metal corrosion of metal pipe or other equipment used in a crude unit.
21. The treated hydrocarbon emulsion of claim 17 in an absence of a different added corrosion inhibitor.