Method for extracting sodium dimethyl isophthalate-5-sulfonate, sodium sulfate and pure water from sodium dimethyl isophthalate-5-sulfonate process wastewater

Abstract

The invention provides a comprehensive utilization method for sodium dimethyl isophthalate-5-sulfonate production process wastewater. The method comprises the following steps: concentrating wastewater, preparing pure water, separating so as to obtain sodium sulfate, and performing distillation, thereby obtaining the sodium dimethyl isophthalate-5-sulfonate. By adopting the method, the content of sulfate radicals (SO4<2->) in the prepared pure water is less than or equal to 0.2mg / kg; the content of chlorine (Cl<->) ions is less than or equal to 0.3mg / kg; the content of ferric (Fe<3+>) ions is less than or equal to 0.2mg / kg; the conductivity of the pure water is less than or equal to 2mu s / cm; sodium sulfate of which the content is 95% or greater is prepared; the prepared trifunctional monomer has the main quality indexes that the acid value is less than or equal to 0.52mgKOH / g, the saponification value is less than or equal to 379.21mgKOH / g; the content of sulfate radicals is less thanor equal to 58mg / kg; the content of Fe<3+> is less than or equal to 2.06mg / kg; the content of Cl- is less than or equal to 4.26mg / kg; the chromaticity (platinum-cobalt colorimetric) is less than or equal to #15; the moisture is less than or equal to 0.25%; the absorbancy is less than or equal to 0.04.

Description

[0001] The present invention is a divisional application of application number 201510886527.3, application date: December 7, 2015, and invention name: "a method for comprehensive utilization of waste water in the production process of three monomers". technical field [0002] The invention belongs to the field of waste water treatment in the organic chemical industry, and specifically relates to a method for comprehensive utilization of process waste water after removing methanol from three monomers. Background technique [0003] Trimonomer (chemical name: dimethyl isophthalate-5-sodium sulfonate) is an important differential modifier, mainly used in polyester, film, etc. Among them, polyester is the main application field, which is used as the third monomer of cationic modified polyester CDP. Because CDP fibers contain sulfonic acid groups, they have good affinity for cationic dyes. The dyed fibers are bright in color, complete in color spectrum, and can be deeply dyed. The...

AI Technical Summary

Problems solved by technology

The disadvantages are: (1) Since the three-monomer wastewater contains a variety of organic substances with different structures and properties, in the resin adsorption process, it is very likely to cause resin deactivation, resin adsorption amount reduction, poor adsorption effect, and low adsorption efficiency. Consequences; (2) The project needs to be frozen to reduce the cooling crystallization and precipitation temperature of the three monomers. High energy consumption leads to high operating costs, and the realization of industrial-scale operation requires large investment and high operating costs

[0008] Chinese patent (patent number: 201410262626.X, patent name: method for extracting isophthalic acid-5-sodium sulfonate from three-monomer production wastewater) proposes to add organic precipitant and sodium hydroxide to three-monomer production wastewater , activated carbon, deionized water, sulfuric acid and activated carbon to extract isophthalic acid-5-sodium sulfonate and sodium sulfate decahydrate from three-monomer production wastewater, although this program has made progress in the comprehensive utilization of three-monomer wastewater, but New solid hazardous waste activated carbon has been added, new pollutants have been added, and water is still not comprehensively utilized

[0009] Chinese patent (patent number: 201410356437.9, patent name: a method for extracting isophthalic acid-5-sodium sulfonate from three-monomer production wastewater) uses trioctylamine and bis-tertiary amine 2,4-bis(N,N- Dihexyl) aminododecylbenzene two-component complexing agent, 2-heptyl undecanol is selected as co-solvent, sulfonated kerosene and n-octanol two-component are used as diluent, and complex extraction process is adopted. The method for extracting isophthalic acid-5-sodium sulfonate from the waste liquid at the bottom of the tower after methanol is recovered from the three monomers, although the economic benefits of the three monomer products have been improved and the comprehensive utilization of resources has been realized, there is still no comprehensive solution to water pollution. Utilization and Sodium Sulfate Extraction Issues

[0012] (1) The comprehensive utilization value of the three-monomer wastewater is not high, the comprehensive utilization of all materials has not been realized, the pure water that meets the water requirements for the three-monomer production process has not been obtained, and the problems of water utilization and wastewater pollution have not been solved;

[0013] (2) The extraction problem of sodium sulfate with high purity is not solved;

[0014] (3) The recovery of three-monomer from three-monomer wastewater has a low yield and poor quality;

[0015] (4) Although sodium isophthalic acid-5-sulfonate was recycled from the three-monomer wastewater, other components in the wastewater were not fully utilized, and the fundamental pollution problem was not solved;

[0016] (5) After extracting some useful components, new pollution is added, and the existing treatment schemes and devices have high operating costs, large investment, and cumbersome operations

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