High-pressure hydrolysis recovery process for polylactic acid (PLA) residual liquid

The invention discloses a polylactic acid (PLA) residual liquid high-pressure hydrolysis recovery process, which is carried out in a closed environment and comprises the following steps: premixing a to-be-recovered residual liquid and a to-be-recovered annotated water liquid in a buffer tank according to a certain proportion; after pre-mixed substances are circulated and filtered, one part of the substances are internally circulated to a buffer tank, and the other part of the substances are conveyed to a preheater for preheating treatment; and conveying the preheated substance to a closed high-pressure hydrolysis reactor for hydrolysis. The whole device is operated in a closed environment, so that contact between materials and air is avoided, and the product quality is further improved; the continuous recovery technology is achieved, the capacity requirement of products is greatly improved, manual operation is reduced, and the safety of the whole technology is improved. The process is relatively short in trea