Separation of benzene-cyclohexane system by extractive dividing wall column

The separation of benzene-cyclohexane system by the extractive dividing wall column in one column was studied with sulfolane as entrainer and oxylene as cosolvent to obtain suitable base temperature and avoid thermal decomposition of sulfolane. The influences of entrainer to feed ratio, the reflux ratios of two sides, the entrance temperature of entrainer and the mass fraction of cosolvent on the separation of benzene-cyclohexane were investigated. The results indicated that the optimized separation conditions for benzene-cyclohexane were the main column reflux ratio of 1, the benzene rectifying section reflux ratio of 2.5, the entrainer to feed ratio of 6.8 and the solvent entrance temperature of 75℃, under which the cyclohexane mass fraction of the cyclohexane product reached 97.15% and the benzene mass fraction of benzene product reached 96.23%. The acquired parameters of the equipment provided a basis for the further equipment improvement. Due to use one column to separate benzene and cyclohexane, the investment of the device decreased, and the energy requirement of extractive dividing wall column process was 13.4% less than that of conventional extractive distillation process.