Method for recovering caprolactam in benzene distillation residual liquid

The invention provides a method for recovering caprolactam in benzene distillation raffinate, and relates to the technical field of caprolactam production.The method comprises the following steps that the benzene raffinate is subjected to cooling crystallization, a first solid-liquid mixture is obtained, and crystals A are obtained after separation; heating the crystal A to a molten state, cooling to a state of just devitrifying, stirring the liquid at the temperature to obtain a second solid-liquid mixture, and separating to obtain a crystal B; adding a solvent to dissolve the crystal B, and removing insoluble impurities to obtain a caprolactam solution; and carrying out reverse extraction on the caprolactam solution by using desalted water to obtain an aqueous solution of caprolactam. The caprolactam in the benzene distillation residual liquid is effectively recovered, so that the waste of products is reduced. 本发明提供了一种苯蒸馏残液中己内酰胺的回收方法，涉及己内酰胺生产技术领域，所述方法包括以下步骤：对苯残液进行降温结晶，得到第一固液混合物，分离后得到结晶体A；将结晶体A加热到熔融状态，再降温至刚好