METHOD AND ARRANGEMENT FOR CLEANING CONTAMINATED CONDENSATE INCLUDING A COMBINED STRIPPER/CONDENSER

A method and apparatus for cleaning condensate, produced during the production of cellulose pulp, including evaporation of spent liquor, utilizing a cleaning plant having several condensers, coupled in series. Process steam from the last evaporation stage and unclean condensate are introduced into a combined stripper/condenser, the process steam and the condensate being brought to flow in opposite directions so that direct heat exchange occurs, resulting in volatile compounds of the condensate being separated and taken up by the steam with simultaneous indirect cooling, resulting in condensation of the main part of the process steam, and the remaining process steam gradually flowing further on, the process steam being successively cooled first resulting in water and turpentine being condensed and collected and subsequently methanol being condensed. The liquid water portion is separated from the turpentine, which is removed from the plant, and the water portion of the condensate is reintroduced to the stripper/condenser. Methanol is also separated and removed from the plant, and cleaned condensate is collected at the bottom of the combined stripper/condenser and removed from the plant or is further purified.