Solvent recovery process for para-aramid waste

Abstract

The invention relates to a para-aramid waste material solvent recovery process. The process is characterized by: mixing para-aramid waste material and water; conveying the resulting mixture to a crusher to carry out crushing; conveying the crushed mixture to a beating tank to obtain slurry of the para-aramid; conveying the slurry of the para-aramid to a pressure filter through a slurry pump to carry out washing and filtering, wherein the washing water is stored in a liquid storage tank and then is beaten into the pressure filter through a recirculating pump to be recycled; conveying the resulting filtrate from the pressure filter to a evaporator through a filtrate pump to carry out evaporation to obtain a salt and other by-products, conveying the resulting filter cake from the pressure filter to a drier to carry out drying to obtain a solid powder material; conveying the solvent tail gas evaporated from the evaporator and the drier to a rectification tower to carry out separation and recovery. The invention provides a process method for the recovery of the solvent through carrying out crushing, pressure filtering, evaporation, drying and rectification for the para-aramid waste material. With the present invention, cycling utilizations of the N-methylpyrrolidone (NMP) and the pyridine are effectively raised during the para-aramid production process; the production cost is reduced; resource reutilization is realized; the pollution is reduced.

Description

technical field [0001] The invention relates to a para-aramid waste solvent recovery process. Background technique [0002] Characteristics of para-aramid waste and solvent: [0003] Aramid waste is in the form of light yellow strips, which are not easy to break, and contain a large amount of nitrogen methyl pyrrolidone (NMP), a small amount of pyridine and a small amount of water. [0004] Nitromethylpyrrolidone has the characteristics of low volatility, good thermal stability and chemical stability, but is expensive and used in a large amount. [0005] Pyridine has a flash point of 20°C, can form an azeotrope with water, and has a boiling point of 92°C. It is also more expensive. [0006] At present, the domestic para-aramid production process is still immature, and some unqualified lumpy wastes are often produced during the polymerization process. There is also a large amount of nitrogen-methylpyrrolidone (NMP) and pyridine solvents in the waste, and the loss of direct...

AI Technical Summary

Problems solved by technology

There are also a large amount of nitrogen methylpyrrolidone (NMP) and pyridine solvents in the waste, and the loss of direct disposal is very large, and environmental protection is not allowed

The existing production equipment does not have a special waste solvent recovery device, but uses manual soaking to recover the solvent in the waste, which is inefficient and labor-intensive

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