关键词: 废水, 优化, 蒸发

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