Abstract:
In order to make the cloud point extraction (CPE) process economically feasible it is necessary to recover and reuse the surfactant from the effluent stream, which is the coacervate phase solution. This study utilized a bench-scale flash vacuum column to strip out toluene from the t-Octylphenolpolyethoxylate (Triton X-114) coacervate phase. The column used was a differential stripper packed with glass raschig rings and operated under rough vacuum. The Henry's law constant and the partition coefficient of toluene in the surfactant solution were experimentally determined. With a surfactant determined. With a surfactant concentration of 300 mM, the presence of surfactants greatly reduced the Henry's law constant. With co-current flash vacuum stripping at liquid loading rates lower than 0.29cm3/min channeling occurred and caused the overall mass transfer coefficinet (Kxa) to drop with increasing liquid loading rate. Above this liquid loading rate, channeling was eliminated and the effective contact area increased, leading to higher Kxa values. At pressures greater than 100 torr the effect of pressure on Kxa was insignificant. However, at lower pressures, Kxa values increased significantly. The surfactant concentration in the effluent stream remained relatively constant even with changes in liquid loading rate and pressure.
