SELECTIVE PURIFICATION PROCESS Russian patent published in 2000 - IPC

FIELD: chemical engineering. SUBSTANCE: invention is designed for use in liquid extraction processes, in particular, on plants for selective purification of lube fractions with various solvents such as phenol, furfurol, N-methyl-2- pyrrolidone, etc. Process is distinguished by that selective purification is carried out by bringing raw material, fed into middle section of extractor, into countercurrent contact with solvent fed into top section of extractor in presence of antisolvent fed into bottom section of extractor. Intermediate extract solution is withdrawn from extractor between raw material and antisolvent inlet levels and is then fed, conjointly with part of raffinate solution withdrawn from the top of extractor, into heat exchanger for mixing, interaction, and cooling. Cooled combined stream leaving heat exchanger enters extractor at the level below intermediate extract solution outlet level. Solvent is recovered from raffinate solution withdrawn from the top of extractor and from extract solution withdrawn from the bottom of extractor to give raffinate and extract. EFFECT: increased raffinate recovery. 4 dwg, 8 tbl