GB826144A - Process for removing oil from oil-in-water emulsions - Google Patents

Abstract

To recover oil from an oil-in-water emulsion which may contain an emulsifier, stabilizer, salts or the like, the emulsion is passed through an adsorbent artificial resin capable of anion exchange and the exhausted resin is regenerated in a manner appropriate to it. In one example an anion-exchange resin based on a polyalkylene-imine resin is converted into salt form and there is passed through it an emulsion containing crude oil, an anion-active wetting agent and sodium chloride, and having a pH value of from 10 to 11. The treated liquid has a pH below 3. The oil is removed from the resin by carbon tetrachloride, and the resin is regenerated by a mixture of sodium chloride and hydrochloric acid. The solvent layer of the regenerant effluent is separated, and after being re-used several times, the solvent and crude oil are recovered by distillation. In a second example a tanker rinsing water containing crude mineral oil (containing naphthenic acids), an anion-active wetting agent and sodium chloride, and having a pH value of 9.5 is passed through a wide-latticed condensation resin based on an aromatic amine, e.g. metaphenylene diamine, and formaldehyde, and previously converted to the chlorineladen condition. After use the resin is washed, and then regenerated with caustic soda and hydrochloric acid with a short intermediate washing. The rinsing water and regenerant washings are combined, and removed from the oil, which precipitates rapidly. In a third example, an oil-in-water emulsion containing mineral oil, an alcohol sulphonate as an emulsifier, and dissolved salt, is passed through a copolymer of 2-vinyl-pyridine which is crosslinked with para-divinyl-benzene and quaternated at the pyridine nitrogen atom. The resin is regenerated with hydrochloric acid and caustic soda solution saturated with sodium chloride, and after brief washing the resin is washed with petroleum ether from which latter the oil is recovered by distillation.ALSO:To remove oil from an oil-in-water emulsion which may contain an emulsifier, stabiliser, salts or the like, the emulsion is passed through an adsorbent artificial resin capable of anion exchange and the exhausted resin is regenerated in a manner appropriate to it. In one example an anion-exchange resin based on a polyalkylene imine resin is converted into salt form and there is passed through it an emulsion containing crude oil, an anion-active wetting agent and sodium chloride, and having a pH value of from 10 to 11. The treated liquid has a pH below 3. The oil is removed from the resin by carbon tetrachloride, and the resin is regenerated by a mixture of sodium chloride and hydrochloric acid. The solvent layer of the regenerant effluent is separated, and after being re-used several times, the solvent and crude oil are recovered by distillation. In a second example, a tanker rinsing water containing crude mineral oil (containing naphthenic acids), an anion-active wetting agent and sodium chloride, and having a pH value of 9,5 is passed through a wide-latticed condensation resin based on an aromatic amine, e.g. metaphenylene diamine, and formaldehyde, and previously converted to the chloride-laden condition. After use the resin is washed, and then regenerated with caustic soda solution and hydrochloric acid with a short intermediate washing. The rinsing water and regenerant washings are combined, and removed from the oil which precipitates rapidly. In a third example an oil-in-water emulsion containing mineral oil, an alcohol sulphonate as an emulsifier and dissolved salt is passed through a copolymer of 2-vinyl-pyridine which is cross-linked with paradivinyl-benzene and quaternated at the pyridine nitrogen atom. The resin is regenerated with hydrochloric acid and caustic soda solution saturated with sodium chloride, and after brief washing the resin is washed with petroleum ether (boiling at 40-60 DEG C.), residual amounts of the latter, remaining in the resin, being removed by methanol. The dissolved oil is recovered by distilling the petroleum ether.