Process for gas cleaning with reclaimed water

Abstract

Dispersions comprising water and particulate solids i.e. carbon and ash are produced in at least one gas cooling or scrubbing zone by quench cooling or scrubbing, or both the raw gas stream from a partial oxidation gas generator with water. Advantageously, the water may be reclaimed by the subject process. In one embodiment, the carbon-water dispersion containing any ash is mixed with a liquid organic extractant and a liquid aqueous emulsion. The emulsion breaks up, and in a decanting operation a carbon-extractant-water dispersion containing gaseous impurities separates out and floats on a dilute bottoms water layer containing gaseous impurities and some solids. The carbon-extractant-water dispersion is mixed with a heavy liquid hydrocarbon and introduced into a distillation column. The overhead from the distillation column is cooled and separated into a layer of liquid extractant which floats on an aqueous emulsion principally comprising water and containing heavy oil, naphthenic acids and liquid organic extractant. The liquid aqueous emulsion and the liquid extractant are recycled to the decanting operation. In another scheme, the emulsion is mixed with the bottoms water from the decanting operation and fed to a flash column for reclaiming water. Alternately, the aqueous emulsion is broken-up into water and liquid hydrocarbon by heating. The water may be reclaimed in the flash-column and the liquid hydrocarbon may be passed into the gas generator or into the distillation column in admixture with the overhead from the decanter.