环己酮装置废水的环己烷萃取工艺研究

Cyclohexane extraction process of waste water from cyclohexanone plant

以环己烷为萃取剂,萃取环己酮生产装置产生的部分废水,探讨了萃取工艺条件以及不同废水多次萃取后萃余水相的化学耗氧量(COD)和主要组分含量的变化。结果表明:合适的萃取条件为环己烷与废水体积比2∶1,萃取8次;COD最高的轻塔回流槽排水和COD最低的烷三塔回流槽排水最难萃取,COD去除率分别为81%和38%;COD较高的蒸汽喷射泵排水最易萃取,COD去除率为99%;COD较高的废碱蒸发冷凝器排水较易萃取,COD去除率为88%;这4种废水混合后的萃取井水较难萃取,COD去除率为66%;各废水中的环己酮和环己醇可充分萃取,但轻塔回流槽排水中约含质量分数为0.5%的环己二醇难以萃取。

A part of waste water from cyclohexanone plant was extracted by using cyclohexane as the extractant. The extraction process conditions were discussed, as was the change in the chemical oxygen demand （COD） and component content of different waste water during the repeated extraction. The results showed that the rational extraction conditions were as followed： cyclohex- ane/waste water volume ratio 2 ： 1, 8-time extraction; it was the most difficult to extract the drainage from the backflow slots of the light fraction tower with the highest COD and the third alkane tower with the lowest COD, and the COD removal rate was 81% and 38%, respectively; it was the easiest to extract the drainage ~rom steam ejector with the higher COD, and the COD removal rate was 99% ; it was easier to extract the drainage from the waste alkaline evaporation condenser with the higher COD, and the COD removal rate was 88% ; it was more difficult to extract the mixture of these four kinds of waste water in the extraction well, and the COD removal rate was 66% ; and cyclohexanone and cyelohexane could be completely extracted from the waste water, but it was hard to extract about 0.5% cyclohexanediol by mass fraction in the drainage from the backflow slot of light fraction tower.