The Study Of Separation P-cresol And M-cresol By Adsorption

Cresol is a mixture of isomers that include o-cresol?p-cresol and m-cresol?O-cresol can be separated by conventional distillation.The boiling point of p-cresol and m-cresol is very close,so it's too difficult to separate p-cresol and m-cresol.Nowadays the supply is not adequate to the demand was caused by the growing requirement of cresol monomer at home and abroad.Therefore,it has important significance for improving the utilization rate of resources and economic benefits by reseach the separation method for m/p-cresol.This paper review the methods of separation and purification for m/p-cresol of physical and chemical method.Mainly studied the adsorption separation of cresol isomers and the adsorption behavior and technology process of cresol isomers on X zeolite were discussed.With temperature increasing,the equilibrium adsorption loading was decreaseing and the adsorption selectivity coefficient was increasing.So it's propitious to separate cresol isomers by higher temperature and the best adsorption temperature was 90 ?.The adsorption behavior of cresol isomers on X zeolite can be described by the isotherm equation of Extend-Langmuir2 at 90 ?.The equilibrium parameters was estimated and calculated by ASPEN ADSORPTION software.Two processes was included on the adsorption technology of separation cresol isomers,each stage has three steps of adsorption and desorption and distillation.The adsorption effect was the best when the flowrate was 0.1L/min and the ratio of height to diameter was 4 in adsorption column I.With the small particle diameter of adsorbent and small bed voidage,the increased mass transfer resistance and the better adsorption effect was obtained.With the higher concentration of p-cresol,the higher concentration of p-cresol was separated by desorption.Therefore,p-cresol can be refined by the second adsorption.The separation results was the best when reflux ratio was 0.1 and numbers of stages was 16 and feed stage was 10 in distillation tower A.The separation results was the best when reflux ratio was 0.09 and numbers of stages was 17 and feed tage was 11 in distillation tower B.By ASPEN ADSORPTION,the technology of separation cresol isomers by adsorption was simulated.The results of the second adsorption showed that the purity of cresol reached 99.76%and the recovery rate was 92.46%.