Recovering a relatively volatile component of a solution from a less volatile component, e.g. as in solvent recovery

摘要

In a solvent recovery plant including a recovery or distillation tower from which solvent product is recovered overhead, an isothermal separator, preferably a cyclone, is used to separate liquid phase contaminant (i.e. oil in a lubricating oil extraction process) in overhead product and to feed the separated liquid to the recovery tower as reflux. In addition, a portion of the feed to the tower can be branched off and mixed with the overhead product to bring its temperature down to close to the dew point of the solvent vapor. In this way, flooding of the uppermost tower trays and distillation of oil overhead can be overcome.