KRAFT DELIGNIFICATION KINETICS BASED ON LIQUOR ANALYSIS

An inferential method uses a mathematical model with on-line liquor an alysis to predict lignin content of pulp every 5 min. Conductivity, io n chromatography, refractive index, and UV absorbency analysis measure effective alkali, sulfide concentration, total solids, and the lignin content of cooking liquor. Experiments with several initial effective alkali and sulfidity levels used a laboratory digester with screened softwood chips to develop a model that incorporates initial and bulk d elignification phases concentrating on regions of industrial importanc e.