Method for preparing low-grade aliphatic acid from benzene and its homologues waste water

Abstract

The invention relates to a method of using benzene series wastewater to prepare low-class fatty acid, in particular to a method of transforming benzene series wastewater into formic acid and acetic acid. The benzene series material of the invention is the organic matter with the molecular structure containing benzene rings. Benzene series wastewater and oxygen (oxygen gas, air or hydrogen peroxide) are first input into a hydrothermal oxidation reactor; then reaction is carried out under the conditions that: the temperature is 200-450 DEG C; the pressure is 5-20 Mpa; the pH value is 7-14; the addition amount of oxygen is 10-200 percent of the needed oxygen content to oxidize all carbon contained in the benzene series material of wastewater into CO2; reaction time is from 30 s to 30 min. The benzene series material is first oxidized to crack benzene rings, generate muconic acid and other unsaturated diacid; a great amount of formic acid and acetic acid is generated further by controlling the hydrothermal oxidation reaction of unsaturated diacid; finally mixed solution containing a great amount of formic acid and acetic acid is separated to prepare formic acid and acetic acid. Differing from the prior method of realizing mineralization through the thermal oxidative decomposition of wastewater, the invention aims to transform wastewater containing benzene series material into formic acid and acetic acid products which can be utilized, so as to realize the resource utilization of wastes.

Description

technical field [0001] The invention relates to a method for converting benzene series waste water to produce formic acid and acetic acid, which are used as industrial raw materials. Specifically, a hydrothermal oxidation process is used for conversion, which belongs to the technical field of waste resource utilization. Background technique [0002] At present, some benzene series waste water has a large discharge volume, high concentration, and is difficult to degrade, which is the main source of pollution to the environment. Benzene series generally refer to aromatic hydrocarbon compounds containing benzene rings, such as benzene, phenol, toluene, etc. There are serious hazards to human health and ecology, and benzene series have been identified as strong carcinogens by the World Health Organization. It is mainly derived from petrochemical, coal chemical, paint, pesticide, pharmaceutical and other production processes. For example, the black liquor of a paper mill contain...

AI Technical Summary

Problems solved by technology

The hydrothermal oxidation technology adopts supercritical wet catalytic oxidation technology, the reaction conditions are 400℃~500℃, 20MPa~30MPa, and catalysts such as heavy metals need to be added to oxidize all benzene series into CO 2 and H 2 O, the reaction conditions are higher, the corrosion of the reaction vessel is serious, and an additional expensive catalyst needs to be added, and the catalyst may be deactivated simultaneously, and the energy consumption required for the relatively high temperature and pressure of the reaction is high, although The treated wastewater is discharged up to standard without any economic benefits

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