Refining process for acetonitrile-containing wastewater

Abstract

The invention discloses a refining process for acetonitrile-containing wastewater. Benzene is used as an entraining agent, the acetonitrile-containing wastewater is added together with the benzene toa decanter to be separated into two phases, the benzene extracts most of the acetonitrile to an organic phase, the wastewater without a large part of the acetonitrile enters a vacuum distillation column (0.4-0.5 atm), the water at the bottom of the column has purity of more than 99.9%, the organic phase and the top azeotrope of a water refining column are added to a pressure tower (4-5 atm), an acetonitrile having a purity of more than 99.9% is obtained from the bottom of the column, and the azeotrope of the acetonitrile-water-benzene at the top of the column is recycled to the decanter. The pressure is adjusted to achieve heat integration of the top steam of the pressure column and the reboiler of a vacuum column, and the column stream is used for preheating of an inlet material. Comparedwith an existing extractive rectification process, the process is simple, the advantages in cost and energy consumption are obvious, the energy consumption is reduced by more than 40%, and the implementation is strong.

Description

technical field [0001] The invention relates to the field of separation and purification, in particular to a process for refining waste water containing acetonitrile. Background technique [0002] The main use of acetonitrile is as a solvent. For example, as a solvent for extracting butadiene, a solvent for synthetic fibers and a solvent for some special coatings. Solvents used in the petroleum industry to remove tar, phenol, etc. from petroleum hydrocarbons. In the oil industry, it is used as a solvent for extracting fatty acids from animal and vegetable oils. Acetonitrile is also an important organic intermediate in fine chemicals, widely used in fabric dyeing, lighting, fragrance manufacturing and photosensitive material manufacturing. In the application as a solvent, a large amount of acetonitrile wastewater will be produced. Recycling acetonitrile in the wastewater can not only reduce environmental pollution, but also obtain high value-added acetonitrile products. H...

AI Technical Summary

Problems solved by technology

Although the above technologies all disclose the separation and purification of wastewater containing acetonitrile, the technical solutions disclosed in the current technology have the technical problems of complex process energy consumption and high cost

[0004] Therefore, considering that the acetonitrile content in acetonitrile wastewater is relatively low, and there is azeotropy, the separation process is energy-intensive, and a new separation technology is developed to study a refining process for acetonitrile-containing wastewater to realize the recovery of acetonitrile. Simultaneously reducing the energy consumption of the separation process is an urgent problem for those skilled in the art

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