Research On Extraction Process Of Phenol Oil

Phenolic compounds are important chemical raw materials,and can produce bisphenol A,phenolic resins,and antidotes.They are widely used.Phenolic compounds are mainly obtained by separation and purification of coal tar or coal liquefied oil.However,with gradually increaseing in demand for downstream products,the existing production capacity has gradually failed to meet the demand for phenolic compounds,especially lower phenols such as phenol and cresols.It is necessary to find new ways to obtain phenolic compounds.Coking phenolic oil is a by-product of delayed coking process.The compositions are complex and mainly contain aromatic hydrocarbons,alkanes and phenolic compounds.Among them,the content of phenols is as high as 30%-50%and phenol and cresols are the main components.Generally,phenolic compounds need to be removed by hydrorefining to ensure the stability of the oil.As crude oil gradually deteriorates,the content of phenolic compounds in coking phenol oil will increase.At the same time,the difficulty of hydrofinishing will also increase.So,it is necessary to collect phenolic compounds for recovery.The main method of removing phenol is alkaline washing,which pollutes the environment.In this study,ethylene glycol which is environmentally friendly is used as the extractant to work on the extraction and separation of coking phenol oil.Then,a process for extracting phenol oil is established.Liquid-liquid equilibrium data is the basis of extraction research.Due to the low liquid-liquid equilibrium data of coking phenol oil system,in reported papers,the ternary equilibrium data of the o-cresol-m-xylene-ethylene glycol system were measured at 30℃,40℃and 50℃by using a self-designed liquid-liquid equilibrium apparatus and analysis of the extraction capacity of ethylene glycol is analyzed.The reliability of the liquid-liquid equilibrium data at different temperatures is verified by Hand,Bachman as well as Othmer-Tobias equations.The linear correlation coefficient squares R~2 of the three equations are greater than 0.99,that indicates that the experimental data reliability is high.NRTL and UNIQUAC model are used to correlate experimental data.The model parameters of the ternary system are obtained by regression.The root mean square deviations(RMSD)of the two models are less than 1.8%,indicating that the regression NRTL and UNIQUAC model can describe the phase equilibrium behavior of the ternary system.A process for extracting phenol oil is established by using a petrochemical coking phenol oil as a raw material.The phenol oil is extracted with ethylene glycol.Then,back extraction is used to separate glycol and phenols,because the boiling points of ethylene glycol and phenols are close.This process uses toluene as the back extractant,which involves extraction,stripping,ethylene glycol recovery,toluene recovery and other parts.Sensitivity analysis of dose-to-oil ratio,ethylene glycol feed temperature in extraction tower;stripping ratio,toluene feed temperature in stripping tower;theoretical number,feed position,reflux ratio in toluene recovery towers and others is used to determine the operating parameters of the entire process.The phenol mass fraction in the final phenol mixture reaches 89.9%,that provides new ideas for the design of phenol oil dephenolization process.