Study On Extraction And Purification Of Phenol From Medium And Low Temperature Coal Tar

China is rich in coal resources.A large amount of coal tar is produced in the process of coal conversion.The components of medium and low temperature coal tar are complex,and the contents of phenols and naphthalene are high.Extracting them can improve the added value of coal processing.The traditional alkali washing method is seriously polluted,and the impurity content of the solvent extraction method is too high,so it is urgent to develop an environmental friendly and efficient extraction process.In this paper,the extraction process of phenol with ethanolamine as extractant was studied.The extraction efficiency was up to 90%.The optimal extraction conditions are as follows:In order to solve the problem of high content of naphthalene in the extraction of phenol,and based on the analysis of the characteristics of the vapor-liquid equilibrium relationship of this system,a series of distillation and crystallization experiments were carried out to separate naphthalene from phenol based on the minimum azeotrope formed by ethanolamine and naphthalene.The first crystallization temperature was controlled at 40 ?,the stirring rate was controlled at 200 R / min,and the second crystallization temperature was controlled at 5 ?.Under the above conditions,the removal rate of naphthalene in the first crystallization is 25.24%,and the purity of naphthalene reaches 95%,which can be sold directly.After the second crystallization,the removal rates of naphthalene,1-methylnaphthalene and 2-methylnaphthalene are 74.11%,4.92% and 46.68%,respectively.These data show that the separation of ethanolamine and naphthalene compounds can be achieved by crystallization method,and these data can provide relevant parameters for subsequent simulation process.Finally,the content of naphthalene products in crude phenol can be reduced to 1.2%,and the crude naphthalene and mixed naphthalene products that meet the requirements can be obtained.Finally,the conceptual design of the process and process for simultaneous extraction of phenol and naphthalene from medium and low temperature coal tar was carried out by using simulation technology,and the process parameters were optimized.Under the optimal operating conditions,the simulation results show that the process is feasible.In this paper,ethanolamine was used as extractant,and crude phenol and naphthalene were extracted from medium and low temperature coal tar by distillation and fractional crystallization.This series of methods can not only achieve high separation effect,but also avoid environmental pollution.Finally,Aspen Plus software is used to simulate,and good results are obtained,which provides a theoretical basis for the realization of subsequent industrialization.