Compositions and methods of removing contaminants in refinery desalting

A method of transferring contaminants from a hydrocarbon phase to a water phase in a refinery desalting process comprising:

• adding to a wash water an effective amount of a composition 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, and where the polyhydroxy carboxylic acid does not include gluconic acid, ammonium salts thereof, alkali metal salts thereof, and mixtures of any of these, where the wash water has a pH of 6 or below;
• mixing the wash water with crude oil to create an emulsion;
• and
• resolving the emulsion into the hydrocarbon phase and the aqueous phase in a refinery desalting process using electrostatic coalescence, where at least a portion of the contaminants are transferred to the aqueous phase;
• where the effective amount of the composition additionally inhibits metal corrosion of metal pipe or other equipment used in a crude unit, and the method additionally comprises inhibiting metal corrosion, in an absence of a different added corrosion inhibitor.

A method of transferring contaminants from a hydrocarbon phase to a water phase in a refinery desalting process comprising:

• adding to a wash water an effective amount of a composition 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, and where the polyhydroxy carboxylic acid does not include gluconic acid, ammonium salts thereof, alkali metal salts thereof, and mixtures of any of these, where the wash water has a pH of 6 or below;
• mixing the wash water with crude oil to create an emulsion;
• and
• resolving the emulsion into the hydrocarbon phase and the aqueous phase in a refinery desalting process using electrostatic coalescence, where at least a portion of the contaminants are transferred to the aqueous phase;
• where:
• the contaminant is 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;
• and
• the polyhydroxy carboxylic acid forms a molar 1:1 salt with the contaminant.