Treatment method for the discharge of pyromellitic dianhydride produced by air gas phase oxidation

Abstract

The invention provides a treatment method for emissions from production of pyromellitic dianhydride through an air gas-phase oxidation method. The treatment method comprises the following steps: using a potassium hydroxide aqueous solution as absorption liquid to absorb process exhaust gas; mixing obtained alkali washing liquid with process waste water; adding process waste material to obtain mixture liquid; adjusting the mixture liquid to be neutral through solid potassium hydroxide so as to prepare three wastes of a process into an organic potassium aqueous solution which meets limit standards of harmful elements such as heavy metal in a fertilizer product, which are specified by an industrial low-toxicity standard and an agricultural industry standard. The treatment method is simple to operate and suitable for large-scale promotion, industrialization is facilitated, the problem about the reasonable and environment-friendly treatment of three wastes in the process of production of pyromellitic dianhydride through the air gas-phase oxidation method can be solved, meanwhile, the obtained organic potassium aqueous solution can be applied to crops as organic potassium fertilizer, and the organic potassium fertilizer has the fertilization characteristics of good fertilizer efficiency and remarkable yield increase, so that harmless and zero-emission treatment of three wastes is realized.

Description

technical field [0001] The invention relates to a treatment method for the discharge of pyromellitic dianhydride produced by an air gas phase oxidation method, and belongs to the field of chemical environmental protection. Background technique [0002] Pyromellitic dianhydride (homellitic anhydride) is an organic chemical intermediate, which is used as a raw material to produce engineering plastics, coating additives, plastic additives, adhesives, etc., especially as a raw material for polyimide production , the prepared polyimide film, polyimide resin and other products are widely used in electromechanical, electronic, aviation and many other fields because of their excellent electrical insulation, high and low temperature resistance, mechanical and other properties. [0003] At present, there are usually two methods for industrial production of homoanhydride: liquid phase oxidation and air gas phase oxidation. The air gas phase oxidation method is generally completed by u...

AI Technical Summary

Problems solved by technology

Although this technology solves the problems of waste pollution and resource reuse in the production of homoanhydride, the products produced can only be used for low-grade polyvinyl chloride products, and the large amount of wastewater discharged during the alkali washing process increases the burden of wastewater treatment.

[0008] For the large amount of high-concentration organic acid wastewater produced during the production process of reaction tail gas washing and hydrolysis of homomellitic acid, it is currently diluted and directly sent to the biochemical pool for treatment, which not only costs high and wastes resources, but also cannot guarantee Completely remove acid and certain toxic substances in wastewater

In the prior art, it is also reported that the process of "oil separation-catalytic oxidation-neutralization-coagulation-UFB anaerobic-combined biological contact oxidation process-air flotation" is used for the treatment of wastewater in the production of homoanhydride, in which the Fenton reagent is used to catalyze the oxidation Pretreatment can reduce the COD index of wastewater, significantly improve its biodegradability, and contribute to subsequent biochemical treatment. However, the method for pretreatment of homogeneous anhydride wastewater by Fenton reagent still needs to be processed through multi-step complex processes to make the wastewater reach Discharge standards, complicated wastewater treatment process

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