Method for pre-treating epoxy resin wastewater before evaporation

Abstract

The invention relates to a method for pre-treating epoxy resin wastewater before evaporation. The method is characterized by comprising the following steps: (1) adding a hydrochloric acid solution into wastewater discharged by an epoxy resin production device, and adjusting the pH value to be 8-10; (2) mixing the wastewater in the step (1) with a coagulant with mass fraction of 3%-5%, reacting and feeding into a pre-treatment device; (3) adding a coagulant aid with mass fraction of 0.1%-0.2% into the pre-treatment device for pre-treatment; (4) filtering pre-treated wastewater; (5) preheating the filtered wastewater, and feeding the preheated wastewater into a reduced pressure desolventizing tower with pressure of 10kPa-20kPa, thereby obtaining reusable water capable of being used for washing the epoxy resin device from the top of the tower; (6) adding a filter aid into tower kettle materials subjected to reduced pressure desolvation, filtering through a secondary filter, and evaporating by adopting a multi-effect evaporation process, wherein the addition amount of the filter aid is 1g / l to 10g / l of wastewater. According to the method, the area occupation is small, the washing cycle of a multi-effect evaporator is prolonged, and the quality of recovered salt is improved.

Description

technical field [0001] The invention relates to a pretreatment method for epoxy resin wastewater before evaporation, in particular to a pretreatment method for epoxy resin production equipment with high salt content and high organic matter before evaporation, and belongs to the technical field of sewage treatment. Background technique [0002] The production process of epoxy resin is that bisphenol A and epichlorohydrin generate crude epoxy resin under the action of sodium hydroxide. During the production process, a large amount of sodium chloride is produced by-product, and finally discharged in the form of aqueous solution, forming a high-salt 1. Refractory wastewater with high organic matter content. This part of wastewater is a mixture of high-concentration organic wastewater and inorganic wastewater. The composition is very complex and can be divided into three categories: (1) Organic matter is mainly a macromolecular intermediate product in the production process of epo...

AI Technical Summary

Problems solved by technology

The pretreatment effect before multi-effect evaporation of this method is not ideal, resulting in poor efficiency and operational reliability of multi-effect evaporation, and short cleaning cycle

Secondly, the quality of the obtained salt is poor, high-quality industrial salt cannot be obtained, the economic benefit is poor, and the amount of steam is large

In addition, the water-soluble organic impurities in this method have no outlet in the multi-effect evaporation circulation system. With the long-term circulation of the mother liquor, it will affect the stability of the multi-effect evaporation production and the evaporation raffinate containing high salt needs to be regularly treated with a special The incinerator is incinerated, and the treatment cost is high