Abstract: 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.

Abstract: A distillation tower (1) has a plurality of liquid sidestream lines (5, 6, 7) and a multi-stage sidestream stripper (13) which includes a respective stripping section (14, 15, 16) for each sidestream line housed in a common, upright, cylindrical shell (28) which allows vapor to pass freely from each stage to the one above. Partial vaporization of each sidestream is achieved by applying a vacuum to the top of the stripper shell (point 21) and/or introducing strip gas at the bottom (point 20). Because the vapor passes serially through the stripping sections from the bottom of the stripper (13) to the top, the need to supply strip gas separately to the stripping sections and/or apply vacuum individually is avoided. The separation between the sidestream products is improved by including, in each stage, a rectification zone (22, 23, 24) positioned above the stripping section.

Abstract: A wash liquid distributor is described for applying liquid uniformly across a filter cake on a filter surface providing effective washing and exhibiting resistance to clogging and fouling.

Abstract: An improved DILCHILL* dewaxing process wherein waxy lubricating oil stocks are solvent dewaxed by contacting them with successive increments of cold dewaxing solvent at a plurality of points along the height of a vertical tower divided into a plurality of stages while agitating the oilsolvent mixture in each stage to provide substantially instantaneous mixing of the waxy oil and solvent thereby precipitating wax from the oil while avoiding the well known shock chilling effect. The improvement resides in adjusting the cold solvent addition to each stage in a manner so as to modify the temperature profile along the tower to ensure that the temperature drop per stage in the initial stages in which wax precipitation occurs is greater than the temperature drop per stage in the final or later stages in which wax precipitation occurs.* DILCHILL is a registered Service Mark of Exxon Research and Engineering Company.