Caprolactam production wastewater treatment method

Abstract

The invention relates to wastewater treatment, in particular to a caprolactam production wastewater treatment method which comprises the following steps of: S1, distillation treatment of production wastewater: performing normal-pressure feeding distillation treatment on caprolactam production wastewater, continuously obtaining distillation condensate and distillation raffinate respectively in thedistillation process, and distilling until crystals are separated out of the distillation raffinate; and S2, distillation raffinate recovery: standing the obtained distillation raffinate for layering,dividing the distillation raffinate into an upper-layer substance, a middle-layer liquid and a lower-layer crystal, recovering the upper-layer substance and the lower-layer crystal of the distillation raffinate, and continuing distillation treatment of the middle-layer liquid in the step S1. According to the method, organic matters and ammonium sulfate are effectively recycled at low cost, and resource utilization is achieved.

Description

technical field [0001] The invention relates to wastewater treatment, in particular to a method for treating wastewater produced by caprolactam. Background technique [0002] The molecular formula of caprolactam is C 6 h 11 NO, the appearance is white powder or crystal, with oily feel. Caprolactam is one of the important organic chemical raw materials. Its main purpose is to produce polyamide chips (usually called nylon-6 chips, or nylon-6 chips) through polymerization, which can be further processed into nylon fibers, engineering plastics, and plastic films. Nylon-6 slices have different application areas depending on the quality and index. [0003] Chemical oxygen demand, or COD, represents the amount of oxygen required for potassium dichromate to oxidize organic matter in one liter of sewage under strong acidic conditions, and can roughly represent the amount of organic matter in sewage. [0004] The COD of caprolactam production wastewater is about 40000mg / L, the amm...

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Problems solved by technology

[0006] 1. This method has complex process, difficult operation, large energy consumption, and high production and operation costs;

[0007] 2. Both caprolactam and ammonium sulfate in wastewater cannot be recycled, and are eventually incinerated, resulting in waste

[0008] In the patent with the authorization number CN103708646B, a method for treating caprolactam industrial wastewater is disclosed, which adopts an improved wet oxidation method and introduces H 2 o 2 As an oxidant, it has a high COD removal rate, but the organic matter and ammonium sulfate in the wastewater cannot be recovered, resulting in a waste of resources

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