Recovery process of phenol and ammonia from coal gasification wastewater

Abstract

The invention relates to the technical field of wastewater treatment, in particular to a process for recovering phenol and ammonia from coal gasification wastewater. The steps are to divide the feed wastewater into cold feed and hot feed respectively and enter the sour water stripping tower from the tower top and the middle and upper part of the tower respectively. The pressure is set at 0.92-1.25MPa, the temperature of the tower kettle is at 178-188°C, the acid gas is produced from the top of the tower, and the ammonia water vapor is produced from the side line; the ammonia water vapor is used as the heat source of the phenol tower and the solvent stripping tower reboiler in turn, and then enters The three-stage fractional condensation system is concentrated into crude ammonia; the kettle liquid of the sour water stripping tower enters the extraction device for dephenolization, and the extraction phase enters the phenol tower, and the extraction agent and crude phenol are separated by rectification; the raffinate phase enters the solvent stripping tower, The extractant dissolved in the wastewater is stripped and returned to the extraction tower. By adopting the process of the invention, the consumption of steam can be greatly saved, and better treatment effect can be guaranteed.

Description

technical field [0001] The invention relates to the technical field of wastewater treatment, in particular to a process for recovering phenol and ammonia from coal gasification wastewater. Background technique [0002] Coal gasification is one of the key links in coal chemical industry and coal gas production. Among them, technologies such as Lurgi pressurized gasifier, pulverized coal pressurized gasifier, Yunmei furnace, and BGL gasifier have achieved great success in converting low-rank coal. widely used. Due to the difference in conversion process and raw materials, for every ton of coal converted, 0.2-1.2 tons of phenolic wastewater will be produced. The main components of the wastewater are phenol, ammonia, carbon dioxide, hydrogen sulfide, etc., which belong to high-concentration refractory organic industrial wastewater. Among them, acid gases, ammonia, and phenolic substances affect the biochemical treatment process, and must be removed and recovered before they ca...

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Problems solved by technology

[0004] The purpose of the present invention is to overcome the defect of large steam consumption in the above-mentioned coal gasification wastewater phenol ammonia recovery process existing in the prior art, and provide an energy-saving coal gasification wastewater phenol ammonia recovery process, which can greatly save steam consumption, and Can guarantee better treatment effect

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