Solvent recovery

A brief overview is presented of the economic significance of solvent recovery in the oilseed extraction industry in view of the steep price advance of hexane since 1974. The present solvent recovery practices in oilseed plants are outlined with addition of operating techniques since 1976. Also, industry trends are noted in terms of improved equipment. Information is presented on the expected solvent losses in various recovery steps in the normal solvent plant operation. Techniques for measuring solvent losses in vent gas effluent, waste water effluent and extracted oil production stream are outlined. The areas of greatest solvent loss are the desolventizer‐toaster (DT) meal outlet stream and the various mechanical leaks in the process machinery. Some discussion is presented on the lack of ability to better define the solvent loss associated with meal discharge stream from the DT unit. Various deficiencies are pointed out in testing procedures and a suggestion is made for increased work in the field to substantiate a better value for solvent loss determination in DT meal.