Abstract: The traditional caprolactam waste liquid concentration process has such problems as high energy consumption, high ammonia content in waste water and large space occupied by the plant.Therefore, a new concentrating process for the treatment of caprolactam wastewater is proposed.The process is implemented in two steps:the first step is deamination pretreatment, and the wastewater is treated repeatedly by pre-deamination tank and wastewater deamination tower while controlling the amount of caustic soda in the pre-deamination tank.Moreover, the ammonia in the wastewater of pre-deamination tank be removed through the high temperature analysis by the secondary ammonia-containing steam of wastewater deamination tower, which removes/recycles ammonia from the wastewater with lower energy consumption.The second step is concentrated treatment; the waste stripping tower is used to wastewater evaporation and concentration through secondary steam recompression technology, which effectively reduce the cost of energy by using electric energy to replace the steam consumption.The number of equipment in optimized process is only half of the traditional concentration process and the construction area is greatly reduced.With an annual output of 100000 tons of caprolactam project as an engineering example, the new concentration process can save about 7.21 million yuan of energy running cost each year, recycle 473.7 tons of ammonia water, and indirectly reduce the treatment cost of ammonia-containing wastewater in wastewater treatment plant.The construction area of the new process is only 1/3 of the traditional concentrated process.Both the Aspen theoretical calculation and practical engineering practice data show that:the process has the advantage in energy-saving, eliminates ammonia pollution to the environment from the source, and effectively reduces the construction area.

Key words: wastewater, optimization, evaporation

摘要： 传统己内酰胺废液浓缩工艺存在着能耗高、排出废水氨含量高以及装置占地面积大等问题，为此，本文提出一种处理己内酰胺废液的新型浓缩工艺。工艺分两步实施：第一步是脱氨预处理，通过预脱氨罐和废液脱氨塔两套系统对废液进行反复脱氨处理；控制预脱氨罐中烧碱的加入量，利用废液脱氨塔塔顶的二次含氨蒸气对预脱氨罐中的废液进行高温解析，以较低的能耗脱除废液中的氨，并加以回收利用；第二步是浓缩处理，通过废液汽提塔对废液进行蒸发浓缩，利用二次蒸汽再压缩技术进行蒸发，采用电能替代蒸汽消耗的方式，有效降低能耗成本。优化后的设备数量只有传统浓缩工艺的一半，装置建筑面积大大减小。以年产10万吨己内酰胺项目为工程实例，采用新型浓缩工艺每年可节省约721万元的能源运行成本；每年回收氨水473.7t，同时间接减轻废水处理厂对含氨废水的处理成本；新工艺所需的项目建筑面积仅为传统浓缩工艺的1/3。Aspen理论计算和实际工程实践的数据表明：本工艺节能优势明显，从工艺源头上消除了氨对环境的污染，并且加以回收利用，同时有效减少了建筑面积。

关键词: 废水, 优化, 蒸发