Vapour-liquid equilibriums for kraft mill condensates

Volatile organic compounds (VOC) cause odour problems and constitute a significant part of the chemical oxygen demand (COD) emissions from the kraft mill. Most of these are found in the cooking and evaporation condensates. The design of efficient methods for the removal of the VOC requires knowledge of the vapour-liquid (VLE) and liquid-liquid equilibrium (LLE). In the present study VLE for the most common VOC in kraft mill condensates were investigated The investigation was based on VLE and LLE darn found in the literature, complemented with new experimental data. The data were used to determine the parameters in the Wilson and NRTL equations for activity coefficients, which were used to calculate VLE for VOCs in condensates and other VOC rich streams in the kraft mill. The model was verified by comparison with experimental data for a typical evaporation condensate.