Metallgesellschaft Aktiengesellschaft

Fritz Wohler

Paul Wiesner

Hans-Martin Stonner

Alfred Schmidt

Hans M Stonner

Alfred Garber

Gas condensates formed from the gases obtained from coal gasification, cokefication, or carbonization are extracted with an acid- and alkali-resistant solvent, e.g. organic esters or ethers, and phenols are thereby removed. The extract is separated into solvent and phenolic phases and the solvent is recycled to the extraction process. The same solvent is used in a greater quantity for a second stage treatment of the gas condensate to preferentially remove tar bases and again the solvent and tar base phases are separated with recycling of the solvent. Residual solvent, acid gases and other volatile components are removed from the gas condensate by distillation and/or stripping with the ammonia and acid gases being separately recovered. The gas condensate is thereafter subjected to biological cleaning, e.g. by a biological oxidation.

Process for reducing biological oxygen demand of gas condensate

The aqueous effluent liquors from gasification or de-gasification of coal are extracted with a water-insoluble solvent and the extract is processed to recover the solvent. The aqueous residue is treated to remove NH.sub.3 in a driving-off column. The invention adds the steps of

Processing aqueous effluent liquors from degasification or gasification

A process for the recovery of pure concentrated ammonia in which the gaseous products of coal gasification or degassing are condensed or are washed with water to produce a phenolic-containing liquid phase (gas water), this liquid is dephenolated by extraction with a solvent, the phenol is recovered from the solvent and the gas is driven from the liquid phase. The gas is washed with circulated phenol and residual solvent is eliminated therefrom after NH.sub.3 is removed by washing.

Process for producing pure concentrated ammonia

Dissolved organic compounds in waste water resulting from coal degassing or gasification processes are removed by extraction with a solvent which is substantially water-immiscible, the solvent residues in the waste water are removed by inert gas scrubbing, and CO.sub.2, H.sub.2 S and NH.sub.3 in the waste water are removed by heating and steam contacting. NH.sub.3 is effectively removed in a steam gas/liquid contacting column by feeding the condensed head product of the column back to the top portion thereof, withdrawing a portion of the condensate from the column at a level intermediate the top and bottom portions of the column, treating the condensate in admixture with waste water containing CO.sub.2, H.sub.2 S and NH.sub.3 in a deacidification gas/liquid contacting column, and feeding the sump product of the deacidification column to the first column at a region below the region at which the condensate is withdrawn but intermediate the top and bottom portions of the NH.sub.3 -removal column.

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Frankfurt-am-Main, Germany

Fritz Wohler