Method for recovering cyanide and ammonia nitrogen in acrylic nitrile waste water using membrane absorption method

A technology for acrylonitrile wastewater and cyanide, which is applied in the direction of metal cyanide, simple alkali metal cyanide, ammonium sulfate, etc., can solve the problems of large equipment investment, high operating cost, and large one-time investment, and achieve cyanide High concentration, small footprint and high separation efficiency

Inactive Publication Date: 2009-03-11
TSINGHUA UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The incineration method needs to consume a large amount of auxiliary fuel oil, which is a great waste of limited energy; the pressurized hydrolysis method has low polymer removal efficiency, and the wastewater after hydrolysis with alkali needs a large amount of water to dilute and neutralize with acid before entering Wastewater treatment plants; the wet oxidation method has high requirements on equipmen

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] The acrylonitrile wastewater used in the test is the quenched first-stage water and second-stage water produced by the synthesis of acrylonitrile from propylene, ammonia and air as the treatment object. The wastewater contains high concentrations of acrylonitrile, cyanide, acetonitrile, acetone cyanohydrin and sulfuric acid. Ammonium etc. Among them, the concentration of cyanide is 824.8~4517mg / L, and the concentration of ammonia nitrogen is 23674~36708mg / L. The hydrophobic hollow fiber membrane is selected from a domestic hydrophobic polypropylene hollow fiber membrane (PP). Firstly, the pH value of the acrylonitrile wastewater was adjusted to 11-12, and the suspended particles were removed through sand filtration and microfiltration (MF) successively. When the wastewater flows in the tube side of the hollow fiber membrane, the volatile NH in the wastewater 3 Gas with 10% H 2 SO 4 The absorption liquid undergoes a neutralization reaction to generate non-volatile (N...

Embodiment 2

[0030] The acrylonitrile wastewater used in the test is the quenched first-stage water and second-stage water produced by the synthesis of acrylonitrile from propylene, ammonia and air as the treatment object. The wastewater contains high concentrations of acrylonitrile, cyanide, acetonitrile, acetone cyanohydrin and sulfuric acid. Ammonium etc. Among them, the concentration of cyanide is 824.8~4517mg / L, and the concentration of ammonia nitrogen is 23674~36708mg / L. The hydrophobic hollow fiber membrane is selected from a domestic hydrophobic polyvinylidene fluoride hollow fiber membrane (PVDF). Firstly, the pH value of the acrylonitrile wastewater was adjusted to 11-12, and the suspended particles were removed through sand filtration and microfiltration (MF) successively. When the wastewater flows in the tube side of the hollow fiber membrane, the volatile NH in the wastewater 3 gas with 20% H 2 SO 4 The absorption liquid undergoes a neutralization reaction to generate non...

Embodiment 3

[0032]The acrylonitrile wastewater used in the test is the quenched first-stage water and second-stage water produced by the synthesis of acrylonitrile from propylene, ammonia and air as the treatment object. The wastewater contains high concentrations of acrylonitrile, cyanide, acetonitrile, acetone cyanohydrin and sulfuric acid. Ammonium etc. Among them, the concentration of cyanide is 824.8~4517mg / L, and the concentration of ammonia nitrogen is 23674~36708mg / L. The hydrophobic hollow fiber membrane is selected from a domestic polypropylene hollow fiber membrane (PP). Firstly, the pH value of the acrylonitrile wastewater was adjusted to 11-12, and the suspended particles were removed through sand filtration and microfiltration (MF) successively. When the wastewater flows in the tube side of the hollow fiber membrane, the volatile NH in the wastewater 3 Gas with 10% H 2 SO 4 The absorption liquid undergoes a neutralization reaction to generate non-volatile (NH 4 ) 2 SO ...

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Abstract

The invention relates to a method for recovering high-concentration cyanide and ammonia nitrogen in acrylonitrile waste water by utilization of the membrane absorption method. The method adopts the double-circulation process to adjust the pH value of the waste water to between 11 and 12 at first; the waste water enters into a tube pass of a hydrophobic hollow-fiber membrane after undergoing sand filtration and micro-filtration (MF) in turn to remove suspended particles; volatile NH3 gas in the waste water generates neutralization reaction with a H2SO4 solution on a boundary surface of the hollow-fiber membrane and an absorption liquid, and nonvolatile (NH4)2SO4 is generated and recovered; due to the hydrophobicity of the membrane, water and other nonvolatile substances are still kept in the waste water; and after the high-concentration ammonia nitrogen is recovered by the membrane absorption method, the pH value of the waste water is adjusted to between 5 and 6, an NaOH solution is used as the absorption liquid of HCN, and then the membrane absorption process is repeated. The membrane absorption method is simple and convenient to operate, has low energy consumption, can recover useful substances, and changes the high-cost treatment condition of the acrylonitrile waste water in the prior art to a certain degree.

Description

technical field [0001] The invention belongs to the technical field of water pollution control, and in particular relates to a method for recovering high-concentration cyanide and ammonia nitrogen in acrylonitrile wastewater by using a hydrophobic gaseous membrane absorption method. This method can change the current high-cost treatment status of acrylonitrile wastewater to a certain extent. Background technique [0002] Acrylonitrile (AN for short), structural formula CH 2 =CH-CN is an important organic chemical raw material widely used in many industrial fields such as synthetic fiber, synthetic chemistry and synthetic rubber. In recent years, with the development of acrylic fiber, ABS / AS, acrylamide and other downstream products of propylene oxide, the demand for acrylonitrile in the world has been increasing. The production process of acrylonitrile is mainly the propylene ammoxidation method (Sohio method), which uses propylene, ammonia and air as raw materials, and ob...

Claims

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Application Information

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IPC IPC(8): C02F1/44C01C3/10C01C1/24
Inventor 何仕均王建龙吴金玲
Owner TSINGHUA UNIV
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