Method for treating production solvent-containing waste liquid from production of m-aramid fibers

Abstract

The invention discloses a method for treating production solvent-containing waste liquid from m-aramid fiber production, which comprises the following steps: (1), filtering production solvent-containing waste liquid produced in the production of m-aramid fibers; (2), delivering liquid obtained by the step (1) to an extracting device to perform extraction separation in an extraction ratio of (1-3):1 and directly discharging the waste water; (3) delivering an extractive phase in a container used in the step (2) to a distillation tower, and subjecting the extractive phase to reduced pressure distillation separation, wherein the filler accounts for 15 to 25 percent of the volume of the distillation tower, the feeding speed is 8.4 to 16.8 percent of the volume of the distilled tower per hour, the temperature in the tower is 80 to 120 DEG C, the temperature at the bottom of the tower is 130 to 150 DEG C, the refluxing speed is 1.7 to 8.5 percent of the volume of the distillation tower per hour, and the discharge speed is 0.7 to 2.5 percent of the volume of the distillation tower per hour; and (4) rectifying the production solvent obtained by the step (3). The method can save energy and causes little corrosion of rectifying device.

Description

technical field [0001] The invention relates to a treatment method for waste liquid, in particular to a treatment method for waste liquid containing production solvent produced in the production process of meta-aramid fibers. Background technique [0002] The waste liquid with a water content of only 80% will be produced in the traditional meta-aramid fiber production process, which contains the production solvent and salt produced in the aramid fiber production process, and the production solvent contained in it is dimethylacetamide. If it is directly discharged into the environment, it will not only seriously pollute the environment, but also cause a huge waste of resources. Therefore, the low-content solvent in the solution must be recovered. At present, rectification is the common treatment method in China. However, even if vacuum distillation is adopted, the energy consumption is huge. The energy consumption of traditional recovery technology is shown in Table-1. In ad...

AI Technical Summary

Problems solved by technology

If it is directly discharged into the environment, it will not only seriously pollute the environment, but also cause a huge waste of resources. Therefore, the low-content solvent in the solution must be recovered

At present, rectification is a common treatment method in China. However, even if vacuum distillation is used, the energy consumption is huge. The energy consumption of traditional recovery technologies is shown in Table-1

In addition, part of the solvent contained in the residue cannot be completely separated, further resulting in waste of resources and increased product costs, and the amount of residue is large, and the disposal cost of the residue is as high as nearly 1,000 yuan per ton

At the same time, because the salt content in the solution is as high as 7%, it causes great corrosion to the rectification equipment and seriously restricts the stability of the rectification operating system