EFFECTS OF PULPING VARIABLES ON DENSITY OF SLASH PINE KRAFT BLACK LIQUORS - PREDICTIVE MODELS

An empirical model of black-liquor density was developed using data fr om 25 liquors produced for a statistically designed experiment in a pi lot-scale digester. The model can predict the density of slash pine bl ack liquors based on four key pulping conditions (effective alkali, su lfidity, cooking time and cooking temperature). Density values calcula ted from the model were within +/-2% of measured values over a wide ra nge of liquor temperature (20-90 degrees C) and solids content (up to 70% solids). The discussion includes a detailed review of the model's underlying principles, which are generally applicable to other liquors .