Cleaning treatment method of glycine production wastewater

Abstract

The invention relates to a cleaning treatment method of glycine production wastewater. The method comprises the following specific steps: firstly adjusting the pH of glycine wastewater to be within arange of 2 to 3.5 through hydrochloric acid, so as to inhibit the decomposition of ammonium chloride; then obtaining condensed water with high ammonia nitrogen and COD contents through an I-effect evaporation system and an II-effect evaporation system, and ensuring that the condensed water directly returns a glycine production system to be recycled, so as to reduce dosages of urotropine and methanol; performing concentration through a vacuum flash evaporation system, so as to obtain condensed water with medium ammonia nitrogen and COD contents; treating the condensed water through a special high-vacuum low-temperature evaporation system; performing low-temperature evaporation, so as to obtain condensed water with low ammonia nitrogen and COD contents, ensuring that the condensed water canmeet an II-grade discharge standard through further organic composite film treatment and biochemical treatment, and ensuring that residual liquid with high ammonia nitrogen and COD contents still returns the glycine system to be recycled. The method is small in equipment investment, realizes harmless mother liquor treatment, is energy-saving and environmentally friendly, ensures that the glycine wastewater can realize close circulation, and is suitable for being widely applied in the glycine industry.

Description

technical field [0001] The invention belongs to the technical field of glycine production, and in particular relates to a cleaning treatment method for glycine production wastewater. Background technique [0002] At present, the domestic production of glycine still adopts the relatively traditional ammonolysis method of chloroacetic acid. The simple process is: using water as a solvent and urotropine as a catalyst, reacting chloroacetic acid and ammonia to produce a mixture of glycine and ammonium chloride. Then add a large amount of methanol for alcohol analysis, and separate the mother liquor containing complex components such as ammonium chloride, glycine, urotropine, water and methanol through a centrifuge to obtain a glycine solid. For the centrifuged mother liquor after separation of glycine, methanol is generally separated by a rectification tower, and then the residual liquid at the bottom of the rectification tower is concentrated by double-effect evaporation (tempe...

AI Technical Summary

Problems solved by technology

However, the reuse of evaporated condensed water will cause the process stability of glycine synthesis and extraction process to deteriorate, and the yield and quality of glycine will also fluctuate with the stability of ammonium chloride recovery process. It is necessary to take into account glycine yield, product quality, ammonium chloride The relationship between recycling processes and wastewater reuse methods, with little process flexibility

Secondly, once the product is unqualified in the glycine synthesis process, the consumption of a large amount of methanol aqueous solution for washing will increase the water volume of the system, which may increase the pressure of condensed water reuse

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