Processing method of effluent brine produced in MDI production process

A production process and treatment method technology, which is applied in the field of industrial waste brine treatment, can solve the problems of large consumption of steam in the stripping tower, large amount of adsorbent, high treatment cost, etc., so as to improve the service life, reduce the degree of pollution, and solve the problem of environmental pollution. pollution effect

Active Publication Date: 2010-03-10
WANHUA CHEMICAL (NINGBO) CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] Patent ZL200710138065.2 discloses a method for the advanced treatment of waste brine produced in the production process of MDI. In this method, due to the use of one-step conventional extraction treatment, the stripper consumes more steam and energy consumption. At the same time, due to The content of organic matter in waste brine before advanced treatment is relatively high, and the consumption of oxidant in the process of advanced treatment is relatively large, the amount of adsorbent is large, and the technical defects of high treatment cost

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0041] The waste brine is transported from the condensation process of the MDI unit and the waste brine tank, and the flow rate is controlled at 1000L / h, wherein the content of aniline is 1.5%, and the content of DAM is 1200ppm. The above-mentioned waste brine and fresh aniline with a flow rate of 100L / h from the aniline raw material tank were respectively fed from the first-stage high-gravity rotary bed (manufactured by the high-gravity engineering technology research center of the Ministry of Education, Beijing University of Chemical Technology, the diameter of the rotor is about 300mm, metal The thickness of the packing layer is about 15mm, and the power is about 5 kilowatts) into two liquid phase inlets, and the speed of the high-gravity rotating bed is controlled at 1000 rpm. Under the action of centrifugal force, the waste brine and extractant flow from the inner edge to the outer edge of the supergravity rotating bed, and flow through the liquid phase outlet to the phase...

Embodiment 2

[0045] Pipette 1200 milliliters of the waste brine of the MDI waste brine tank in Example 1, put it into a 2 liter glass kettle with an inserted aeration tube, add 12 milliliters of concentration 30% hydrogen peroxide (analytically pure, Yantai Institute of Chemical Industry) , carry out chemical oxidation reaction at normal temperature, pass into air, aeration rate 40 liters of air / hour, after 1 hour, waste brine is sent in the glass adsorption column (diameter 30mm, Height 800mm), 100 grams of cylindrical coal-based activated carbon with a diameter of 4mm inside, the temperature of waste brine is 30-40°C, and its residence time in the glass adsorption column is about 12 minutes, and the brine flowing through the adsorption column is collected and analyzed . No aniline and diamine have been detected in the treated brine, TOC is about 6.9ppm, TN is about 1.4ppm, and its organic matter content meets the technological requirements of ion-exchange membrane caustic soda.

Embodiment 3

[0047] The MDI waste brine treated in Example 1 was used for testing.

[0048] Pipette 1200 milliliters of waste salt water from the waste salt water storage tank, put into 2 liters of glass kettles with plug-in aeration pipes, add 6 milliliters of concentration 10% sodium hypochlorite (pure reagent, Yantai Sanhe Chemical Reagent Factory), at 40 The chemical oxidation reaction is carried out at ℃, the air is introduced, and the aeration rate is 40 liters / hour. After 1 hour, the waste brine is sent into the glass adsorption column with a jacket at a flow rate of 540 ml / hour with a metering pump. The adsorption column is the same as in Example 1, the temperature of the waste brine is 30-40° C., and the residence time of the waste brine in the glass adsorption column is about 12 minutes. No aniline and diamine have been detected in the treated brine, TOC is about 6.8ppm, TN is about 1.5ppm, and its organic matter content meets the technological requirements of ion-exchange membra...

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Abstract

The invention discloses a processing method of effluent brine produced in MDI production process, comprising the following steps: (1) effluent brine containing phenylamine, diphenylmethane toluene diamine and polyamine, which is produced in MDI production process, carries out super-gravity extraction, and then tower-type extraction is carried out; (2) effluent brine discharged by the step (1) is fed to a stripping tower to carry out steam stripping; (3) effluent brine discharged from the stripping tower in step (2) and chemical oxidants are conveyed to an oxidation reactor, and air is vented to carry out aeration; (4) the effluent brine processed by the step (3) is transported to an adsorption tower to carry out adsorption. The effluent brine processed by the method of the invention has less than 8ppm of TOC, less than 2.5 ppm of TN (total nitrogen); sodium chloride and water and the other resources in effluent brine are realized, so as to carry out circulating utilization.

Description

technical field [0001] The invention relates to a treatment method of industrial waste brine, more specifically, a treatment method of waste brine produced in the production process of diphenylmethane diisocyanate (hereinafter referred to as MDI). Background technique [0002] MDI is one of the main raw materials in the polyurethane industry. Condensation reaction of aniline and formaldehyde under the action of hydrochloric acid catalyst to obtain polymethylene polyphenyl polyamine, and then use polymethylene polyphenyl polyamine phosgenation reaction to produce monomeric MDI and polymeric MDI, which is a key technology in the polyurethane industry well-known methods. [0003] Aniline and formaldehyde are condensed under the action of hydrochloric acid catalyst to obtain polymethylene polyphenylpolyamine hydrochloride, then neutralized with caustic soda, the brine layer and polyamine layer are separated, and the polyamine layer is washed with process water Refining again t...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F9/10C02F1/20C02F1/26C02F1/72C02F1/76C02F1/78C02F1/28C02F103/36
Inventor 张宏科华卫琦刘小高赵振华孙淑常丁建生陈建峰张鹏远邹海魁初广文许利民
Owner WANHUA CHEMICAL (NINGBO) CO LTD
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