The invention relates to a method for treating
coal gasification
wastewater containing
phenol and
ammonia. The method comprises the following steps: single
tower alkali injection and pressurization steam stripping removal of acidic gas and
ammonia, three-level dephlegmation of
lateral line tapped gas, extraction of
phenol by
diisopropyl ether and
solvent recovery. The cold and hot
coal gasification
wastewater, according to a certain proportion, respectively enters a pressurization single
tower from the upper part and middle upper part of a
wastewater steam stripping
tower, and
acid gas is discharged from the tower top; the
lateral line withdrawal
mixed gas goes through three-level dephlegmation to obtain high-concentration
ammonia, alkali is injected at the position below the
lateral line to transform fixed ammonia into free ammonia which is to be removed; counter-current extraction is carried out on removed ammonia, residue of
acid gas and
diisopropyl ether to dephenolize; extraction
solvent is recovered by a
solvent recovery tower and a solvent steam stripping tower to obtain the byproduct, namely crude
phenol. In the method of the invention, the process removing
acid gas, free ammonia and fixed ammonia is carried out simultaneously on the
coal gasification wastewater in the wastewater steam stripping single tower, as a result, high-concentration ammonia is obtained, the content of
carbon dioxide, sulfureted
hydrogen, free ammonia and fixed ammonia in tower kettle
purified water is extremely low, encrustment is not prone to take place, and the purified
coal gasification wastewater meets the requirement of follow-up biochemical treatment.