煤焦油中酚类和萘类化合物绿色提取工艺概念化流程分析

Conceptual process analysis of green extraction technology of phenols and naphthalenes from coal tar

针对传统的煤焦油碱洗法提酚工艺会产生大量的含酚碱渣和废水、乙醇胺法提酚无二次污染但酚产品中萘含量过高的问题,根据乙醇胺和萘类化合物间的共沸特性,提出了一种乙醇胺法提酚的概念化改进流程和工艺。新流程以乙醇胺为萃取剂,萃取煤焦油中的酚类和部分萘类,利用共沸特性将萘类与含酚萃取物分离,再利用精馏和结晶获得纯度较高的酚类和萘类产品。利用实验和模拟方法进行了工艺验证和流程参数优化,结果显示:在乙醇胺和酚油质量比为2∶1、两步结晶温度分别为40℃和5℃、萃取物分馏塔塔盘数72块、回流比为1.5的情况下,利用该工艺提取的粗酚纯度可达98.68%以上,粗萘纯度可达95%以上。

The traditional process of extracting phenol from coal tar by alkali washing produced a large amount of phenol-containing alkali residue and wastewater.There was no secondary pollution in the process of extracting phenol by ethanolamine,but the content of naphthalene in phenol products was too high.In order to solve the above problems,based on the azeotropic characteristics between ethanolamine and naphthalene compounds,a conceptual improvement process of extracting phenol by ethanolamine was proposed.In the new process,phenols and part of naphthalenes were extracted from coal tar using ethanolamine as the extractant,then the azeotropic characteristics was utilized to separate naphthalenes from extracted substance containing phenol,and high purity phenols and naphthalenes were obtained by distillation and crystallization respectively.The experimental and simulation methods were used to verify the process and optimize the process parameters.The results showed that when the mass ratio of ethanolamine to phenol oil was 2∶1,the two-step crystallization temperature was 40℃and 5℃respectively,the number of trays was 72 for distillation column,and the reflux ratio was 1.5,the purity of crude phenol and crude naphthalene extracted by this process could reach more than 98.68%and 95%respectively.