Recovery process of caprolactam refining raffinate

Abstract

The invention discloses a recovery process of caprolactam refining raffinate. The caprolactam refining raffinate and oxidant are mixed according to the weight part ratio of 3.1:1-3.3:1, reacting while stirring at 32-40DEG C under normal pressure; after the reaction is carried out for 30-40 minutes, the reaction continues for 80-90 minutes while stirring at 78-82DEG C under normal pressure; the products are extracted at ambient temperature and pressure by using an extractant, and an organic extract phase which contains the caprolactam is returned to a water back-extraction system of a CPL device. The recovery process can eliminate reducing impurities and impurities with the properties which are similar to those of the caprolactam in the caprolactam refining raffinate, in particular to impurities which influence 290nm extinction value, PM value and V.B, thus recovering and preparing high-purity caprolactam. By adopting the recovery process, a company which has an annual output of 100 thousand tons of caprolactam can recover 1600-2000 tons of the caprolactam per year which is equivalent to 30 million yuan, thus improving the annual output and the economic benefit and reducing the unit consumption of the caprolactam.

Description

technical field [0001] The invention relates to waste liquid treatment in the field of chemical production, in particular to a process for recovering and purifying caprolactam refining raffinate. Background technique [0002] Caprolactam is a raw material for the production of polyamide, which requires high quality of caprolactam, but the preparation process of caprolactam is long and complicated, so the refining process will produce a large amount of raffinate containing caprolactam, such as light by-product raffinate, heavy by-product Product raffinate, pre-distillation raffinate, alkali distillation raffinate, etc. [0003] At present, the treatment of these residual liquids either returns to the neutralization and extraction after the Beckmann rearrangement, continues to pollute the system, and affects the quality of caprolactam, or is incinerated as waste liquid, thereby increasing the unit consumption of caprolactam. For an annual output of 100,000 tons For caprolacta...

AI Technical Summary

Problems solved by technology

[0002] Caprolactam is a raw material for the production of polyamide, which requires high quality of caprolactam, but the preparation process of caprolactam is long and complicated, so the refining process will produce a large amount of raffinate containing caprolactam, such as light by-product raffinate, heavy by-product Product raffinate, pre-distillation raffinate, alkali distillation raffinate, etc.

[0003] At present, the treatment of these residual liquids either returns to the neutralization and extraction after the Beckmann rearrangement, continues to pollute the system, and affects the quality of caprolactam, or is incinerated as waste liquid, thereby increasing the unit consumption of caprolactam. For an annual output of 100,000 tons For caprolactam production enterprises, the annual loss of caprolactam is 1600-2000 tons, equivalent to an economic loss of more than 30 million yuan, which increases the production cost of caprolactam