STUDIES ON THE HEAT-CAPACITY OF SLASH PINE KRAFT BLACK LIQUORS - EFFECTS OF TEMPERATURE AND SOLIDS CONCENTRATIONS

Heat capacities of different kraft black liquors from statistically de signed experiments for pulping slash pine were measured as a function of solids concentrations over a temperature range of (313.2 to 393.2) K using differential scanning calorimetry. The dependency of heat capa city on temperature and solids concentrations is described in detail. The results indicate that kraft black liquors are nonideal solutions, and their thermal properties cannot be predicted from the properties o f pure water and solids. The excess heat capacities were determined us ing a binary solution assumption and are defined with a single correla tion as a function of temperature and solids mass fraction for every s ingle liquor. An empirical method is developed that can be applied to describe the heat capacity behavior of a single liquor as a function o f temperature and solids concentrations. The results of this work show that the heat capacities are directly proportional to the organic-to- inorganic ratio in the liquor.