用恒沸精馏技术从工业废水中回收吡啶

Recovering Pyridine from Industrial Waste Water by Means of Continuous Distillation

除虫菊酯类农药生产过程中产生含有高浓度吡啶的废水,采用恒沸精馏技术处理该类废水并从中回收吡啶。恒沸精馏技术条件:酸性含吡啶的废水经加碱中和后,在92.6℃下进行恒沸精馏(蒸出率取30%,回流比取3￣4)得到粗吡啶;在回收的粗吡啶中加入适量的脱水剂在70℃左右进行共沸脱水,将脱水后的粗吡啶再精馏(回流比取3),收集在114℃￣116℃的主馏分即得到精制吡啶。试验研究结果表明:吡啶的去除率达98%,回收率达95%以上,回收的吡啶含量达99.5%以上,完全达到回用的目的,回收吡啶后的废水为后续的废水处理创造了条件。

Pyrethroid pesticide production produces waste water containing high concentrations of pyridine. In this research we used a continuous distillation technique to treat this waste water and to recover the pyridine. Conditions were as follows. After neutralization by adding base to the acidic waste water containing pyridine, continuous distil- lation was conducted at 92.6℃ (evaporation rate was 30% with 3 to 4 refluxes), and impure pyridine was obtained. While recovering the pyridine, an appropriate amount of dehydrating agent was added and distillation was conducted at about 70℃. After the water was evaporated, the impure pyridine was again distilled with 3 refluxes, with the main fraction at 114 to 116℃ being pure pyridine. The experimental results showed that up to 98% of the pyridine could be removed, and greater than 95% of the pyridine recovered with a purity of more than 99.5%. Thus pyridine recovered from the waste water was completely reusable, and the waste water following pyridine removal was more easily handled in subsequent treatment.