| 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 the raw gas stream from a partial oxidation gas generator with water. The dispersions are resolved by liquid extraction in a decanting zone to produce a water layer containing carbon, dissolved gas, and ash, and also a separate dispersion comprising carbon, extractant, and water. Solids-free water, liquid extractant and uncondensed gases are then separated from each other in a distillation and separation operation. Water is removed from a separation vessel in said operation and introduced on to a stripping plate of a flash column containing at least one stripping plate. The solids-containing water from the decanting zone is flashed below said stripping plate and a portion is converted into steam. The steam passes up through holes or bubble caps in the stripping plate and is dispersed through the water contained on said plate. If desired, a portion of the water obtained from blowing-down a gas cooler may be flashed to steam below the stripping plate. Unvaporized water falls to the bottom of the column where a vertical weir separates the flash column into two chambers. Solids settle out of the water in the first chamber and clarified water flows over the weir into the second chamber. Overflow water from the bottom stripping plate is discharged below the water-level in the second chamber by way of a downcomer. Reclaimed water is pumped to said gas cooling and scrubbing zones from the second chamber, and waste water containing solids in the first chamber is discharged from the system. The overhead from the flash column is cooled below the dew point and introduced into said separation vessel. |