Foul Condensate Steam Stripping System Using Pulp Mill Blow Heat as an Energy Source, 1993 Environmental Conference Proceedings

The implementation of a novel concept of using blow heat as the primary energy source to operate a foul condensate steam stripping system is presented in this paper. The process, which was recently commissioned in a southeastern mill uses waste heat from a blow heat accumulator as the heat source for steam generation in a thermal siphon reboiler. The stripping process is accomplished in a tray type stripper column operated under vacuum. A steam ejector provides the motive force to generate the column vacuum and transport the overhead gases for incineration in the lime kiln. The stripper is designed to strip methanol from a combined foul condensate stream and a stream of overflow condensate from the blow heat accumulator. Test results have shown greater than 90% reduction in methanol from the foul condensate and greater than 50% reduction in methanol from the overflow condensate respectively. The paper presents a detailed description of the system along with mass and energy balances. Additionally, performance test data is presented.