The Study Of Extraction Of Carboxylic Acids From Dilute Aqueous Solutions

To get a reliable feasible technique of recovery of carboxylic acids from aqueousby-product in liquefying coal process, the study of extraction carboxylic acids fromdilute aqueous solutions is carried out in this paper. This technique must be going tohave good effect on environment and bring more profits to companies.The extraction of carboxylic acids by chemical complexation with high boilingsolvents is investigated. In this work, the best mixed solvent is determined bycomparing solvents with their extraction ability. Besides this, the liquid-liquidequilibrium data are presented for the system of acetic acid, propinic acid, butyricacid with this given solvent.The separation of carboxylic acids from dilute solutions with pulsed packedcolumn is studied and optimal operating condition is received. The results show thatextract efficiency can reach 97% at 25℃, when volume flows of both solvent and feedare 0.7L/h, pulse frequency is 1/5 s-1,pulse pressure is 1.5 kgf/cm2.Simulation is carried out with EXTRACT model in ASPEN PLUS 10.2, usingUNIQUAC model which is more suitable for liquid-liquid equilibrium. Theparameters of activity coefficient equation can be gotten by data regression frommeasured liquid-liquid equilibrium data. Simulation results agree well with theexperimental values.The effect of temperature on extraction is investigated. The results show that thehigher temperature is, the less extraction efficiency will be received. The results ofthis paper will provide dependable experiment and design methods for magnifyingand industrialization of separation aqueous by-product in liquefying coal process.