Heat-coupled phenol-ammonia wastewater treatment device and method

Abstract

The invention discloses a heat-coupled phenol-ammonia wastewater treatment device. The device comprises a raw material preheater, a deacidification tower, a deamination tower, a water tower and two stages of extraction towers connected with an extract tank in series along a direction from front to back, wherein the two stages of extraction towers are connected with two stages of solvent recovery towers which are connected in series along a direction from front to back; sulfur-containing components are removed from the wastewater through the deacidification tower; ammonia nitrogen in the wastewater is removed through the deamination tower; as the wastewater is extracted through the two stages of extraction towers in sequence, phenol in the wastewater is extracted to an extraction phase andextracted from the top of the extraction tower to serve as a feed of a solvent recovery tower; crude phenol is extracted from the bottom of the latter-stage solvent recovery tower after the wastewateris treated by the two stages of the solvent recovery towers in sequence, and a solvent is extracted from the top of the solvent recovery tower; and meanwhile, a raffinate phase extracted from the bottom of the extraction tower is preheated and then used as a feed of the water tower; an azeotrope extracted from the top of the water tower is recycled as the solvent; and purified water is extractedfrom the bottom of the water tower, is subjected to cooling and then enters a biochemical treatment section. According to the invention, phenol and ammonia in the wastewater are recovered by utilizinga thermal coupling technology, and the purpose of energy conservation in wastewater treatment is achieved.

Description

Technical field [0001] The invention relates to a method for treating wastewater containing phenol and ammonia in coal chemical industry, in particular to an energy-saving method that uses thermal coupling technology to recover phenol and ammonia in wastewater to achieve the purpose of wastewater treatment. Background technique [0002] Most of the existing processes for treating phenol-ammonia wastewater only exchange part of the heat from the deammification tower kettle and the feed, which has low heat utilization rate and high energy consumption. The patent document with the publication number CN102259943A discloses an energy-saving phenol-ammonia wastewater recovery treatment method. It is proposed to heat the phenol tower and the water tower reboiler from the top steam of the ammonia removal tower, eliminating the need for the condensation tower condenser. Although this process can achieve the purpose of energy saving, the ammonia content of the steam at the top of the ammon...

AI Technical Summary

Problems solved by technology

Although this process route can achieve the purpose of energy saving, the ammonia content of the steam at the top of the deammonization tower is high, the temperature is relatively low, and the requirements for the negative pressure of the phenol tower and water tower that receive heat are relatively high; the steam at the top of the deammonization tower can provide The heat depends on the feed and reflux ratio of the deamination tower, and it may not fully meet the heat demand of the phenol tower and water tower, or even the heat demand of a single phenol tower, which lacks backup external heating

Images