Device and method for recovering low-concentration spinning waste liquid produced during preparation of hollow fiber membrane

Abstract

The invention provides a device and a method for recovering a low-concentration spinning waste liquid produced during preparation of a hollow fiber membrane. The device comprises a concentration unit and a distillation unit which are connected with each other, wherein the spinning waste liquid is concentrated by the concentration unit and then enters the distillation unit; the concentration unit comprises a waste liquid tank, a first conveying pump and a microfiltration membrane, the waste liquid tank is connected with the microfiltration membrane through the first conveying pump, and the microfiltration membrane is further connected to the waste liquid tank; the distillation unit comprises a concentration liquid tank, a second conveying pump, a distillation kettle and a rectifying tower, the concentration liquid tank is connected with the distillation kettle through the second conveying pump, and the distillation kettle is further connected to the rectifying tower. According to the recovery method, the low-concentration spinning waste liquid is concentrated and directly distilled, then organic solvents and additives are recovered, the performance of the recovered materials is good, and the economical performance of the recovery process is greatly improved.

Description

technical field [0001] The invention relates to a method for recovering spinning waste liquid, in particular to a low-concentration spinning waste liquid recovery device and method for hollow fiber membranes. Background technique [0002] The hollow fiber membrane generally adopts the wet spinning process, that is, the prepared spinning stock solution is extruded through the spinneret and evenly attached to the surface of the crochet rope, and then enters the gel tank for gel setting. A large amount of membrane-making wastewater is produced, that is, spinning waste liquid, and its main recycled components include DMAC (dimethylacetamide), PEG (polyethylene glycol) and PVP (polyvinylpyrrolidone). [0003] At present, the distillation method is generally used to recover the spinning waste liquid, that is, the spinning waste liquid is directly put into the distillation kettle for heating. When the concentration is low, the value of the solvent and additives recovered by rectif...

AI Technical Summary

Problems solved by technology

Due to the low content of additives and organic solvents in the waste liquid, it is not economical to directly carry out distillation and recovery (a state of loss), and if the waste liquid treatment method of direct distillation is adopted, non-volatile substances such as salt in the waste liquid will be lost. Residues in the recovered materials will increase the content of impurities in the recovered materials and reduce the performance; in addition, the inorganic membrane needs to be under high pressure (need to reach 20kg pressure) to achieve the interception effect, and cannot completely intercept the residence The additives that need to be recovered not only have high operating costs, but also have certain risks. For example, in actual industrial production, operation under 20kg pressure may cause leakage at the connection, resulting in waste liquid spraying out or even bursting of the pipeline

And if the waste liquid is directly discharged into the sewage station, it is obviously a huge burden for the sewage station

Images