Study On Foam Separation Of Surfactant In Water

Foam separation is one of rapidly developed separation techniques among the few decades. The purpose of this paper was to investigate foam separation of aqueous surfactants solution.Using the orthogonal experiment designs, surfactants were selected and the operation parameters were obtained. The results showed that cationic surfactants have the best foam separation efficient. The optimal conditions of foam separation were the air flow rate 0.18 m3 /h, feed surfactant concentration 1CMC, layer number three, the concentration of sodium chloride 1? 0×10?3mol/l.The effects of eleven factors on foam separation were studied with three layer columns. It was found that the enrichment decreased with the increase of air flow rate, surfactant feed concentration, the filling layer, layer height, concentration of sodium chloride, separation time and gas separator size. Recovery increased with increasing air flow rate, increasing surfactant feed concentration, increasing foam height, increasing the filling layer, increasing layer height and increasing separation time. The results showed that the recovery rate increased with increased number of filling stage. The enrichment of CTAC, TDPB, SDBS, SDS, DBS can reach 4.8, 2.3, 4.3, 2.2 and 1.4, respectively. The recovery of CTAC, TDPB can reach 77.5% and 82.5%, respectively.A mathematical model of the semibatch foam fractionation of surfactants was developed. Foam bed is assumed to consist of equal dodecahedral bubbles at any cross section. The model is employed to investigate the effect of coalescence on enrichment. Under reasonable initial and boundary conditions, the differential equations were solved by means of matlab software. Effects of inlet air flow and inlet feed concentration on enrichment rate were predicted by the model. The results had good agreement with the experiment observations.Comparison of enrichments for three different models for coalescence frequencies indicated enrichments decreased in the order In addition, it was found that larger bubble size could result in higher enrichment.