Process for treating industrial waste water containing hydroxybenzene and ammine by double-tower stripping

Abstract

A method for treating wastewater with phenol and ammonia coal from chemical industry by double-tower steam stripping is disclosed. The steps of the technical method of the invention are as follows: 1. acidic gases are deacidified; 2. amino is removed; 3. ammonia is concentrated and purified. The invention has the advantages that: 1. by the method of the invention, acidic gases and ammonia can be removed comparatively thoroughly, residual quantity of the acidic gases can be reduced to be below 10mg / L and the total amount of ammonia can be reduced to below 10mg / L, thereby avoiding the resistance function of the ammonia to the follow-up biochemical section; 2. the method of the invention can greatly improve the desorption rate of phenol or decrease the operation cost of the extraction section; 3. the method of the invention can effectively separate volatile phenol from ammonia, and the content of the volatile phenol and the acidic gases can be decreased to below 10mg / L, thus lightening the energy consumption and purifying load in the follow-up ammonia refining process; 4. the concentration of the ammonia can be improved to over 98 percent; 5. the method can effectively remove oil contaminants with low boiling point.

Description

technical field [0001] The invention relates to a method for treating coal chemical wastewater, in particular to a method for treating phenolic and ammonia-containing coal chemical wastewater by double-tower stripping. Background technique [0002] my country is a big coal country. With the increasing shortage of petroleum resources, the development of coal chemical industries such as coal-to-oil and coal-to-gas is in the ascendant, and serious environmental pollution problems follow. During the process of coal gasification and coking, a large amount of highly polluted wastewater is produced, containing high concentrations of pollutants such as phenol, ammonia, and acid gas. For this type of wastewater, chemical separation process must be adopted to separate out most of the phenol, ammonia and acid gas before entering the subsequent biochemical treatment. [0003] At present, there are more or less problems in the following aspects in the process and technology of coal chem...

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Problems solved by technology

[0003] At present, there are more or less problems in the following aspects in the process and technology of coal chemical wastewater treatment: 1. The unreasonable deacidification process makes the dissolved ionic carbon dioxide, hydrogen sulfide and other acid gases in the wastewater uneconomical and effective. 2. During deamination, the separation of ammonia and phenol is not complete, resulting in high phenol content and acid gas content in the ammonia product, which increases the load on the subsequent ammonia refining section; 3. When the ammonia content in the wastewater is high, the operation of the deammonization tower is unstable

In some processes, ammonia is stripped using a complex tower with side line extraction. When the ammonia concentration is high, the ammonia extraction volume and circulation volume are large, which often leads to unstable tower pressure and fluctuations in ammonia content in purified water.

4. Since the problem of volatile phenols affecting the quality of ammonia cannot be effectively solved, some processes adopt the process of extraction first and then deamination, so the pH during extraction is relatively high

When pH>8, phenol mainly exists in ionic state in water and the hydrophilicity is greatly improved, so that the efficiency of extraction and dephenolization is greatly reduced

[0004] Due to the existence of the above problems, there is currently no relatively mature, reliable, and stable process that can make most of the coal chemical industry wastewater meet the requirements of biochemical treatment continuously and stably after pretreatment

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