Abstract: A method and system for handling foul condensate containing Hazardous Air Pollutants (HAPs) in a cellulose pulp mill has enhanced energy efficiency and lower cooling water usage, while complying with the Cluster Rules and other environmental regulations. The condensate is fed countercurrently to stripping vapor in the stripping column to produce a HAPs vapor and a clean condensate. Part of the clean condensate is fed from the stripping column reboiler, and the HAPs-rich vapor is directed to the reboiler to at least partially condense while vaporizing the clean condensate into the clean vapor (stripping vapor). The pressure of the stripping vapor is increased, such as utilizing a steam ejector, to about 0.1-30 psig and then is used as the stripping vapor in the stripping column. The non-condensed HAPs-rich vapor is fed to an external condenser, and the dirty condensate from the external condenser and the dirty condensate from the reboiler, are returned to the stripping column.

Abstract: A method of treating cellulose pulp mill condensates having an MeOH content using an evaporator and a steam stripper having a reboiler, comprising: (a) Collecting a feed liquor stream having at least 50% of the pulp mill MeOH. (b) Feeding the feed liquor stream to the evaporator having at least two heating element sections separated on a motive steam side. (c) Evaporating the liquor in the evaporator to produce a vapor containing at least 40% of the at least 50% of the pulp mill MeOH. (d) Compressing the vapor from (c) to increase the vapor pressure. (e) Using the vapor from (d) as condensing heating media in (c) for the evaporation in a first heating element section of the evaporator and venting a portion of the vapor through the first heating element section. (f) Compressing the vented vapor from the heating elements of the evaporator from (e) to increase the vapor pressure to be used as heating media in the reboiler.