Abstract:

Single-factor experiments and orthogonal tests were carried out to reveal the effects of such operation conditions as evaporation temperature（θe）,feed flowrate（Q）,feed temperature（θf） and condensation temperature（θc） on the mass ratio D/F of the distillate stream to the feed during the purification of unsaturated monoglyceride by molecular distillation,and an order of the operation conditions affecting the D/F value was found as θe〉Q〉θf〉θc.Then,two quadratic regression equations were established to predict the content of monoglyceride（MAG） and diglyceride（DAG） in the distillate stream at different evaporation temperatures.Moreover,to verify the reliability of the equations,some tests were performed respectively at the feed flowrate of 0.71,1.06,1.42mL/min and the evaporation temperature of 150～200℃,and the results were found to accord well with those predicted by the mo-del.Finally,the variation of unsaturated MAG recovery in the distillate stream with operation conditions was investigated.The results show that,at an θe of 170～190℃,a feed flowrate of 0.71mL/min,a θf of 70℃ and a θc of 60℃,the purity of MAG in the distillate stream is up to more than 80% only with a single-step molecular distillation,and the MAG recovery varies from 60% to 80%.

Key words: molecular distillation, unsaturated monoglyceride, operation condition, orthogonal test