Computer control of bleaching of wood pulp - for paper manufacture

摘要

Valves regulating admission of chlorine, caustic soda and bleach (chlorine dioxide) to each stage of the process are controlled as follows: Chlorine : K factor (lignin content) of input pulp, temp., pulp feed rate, pulp consistency and ratio of chlorine concentration at chlorine tower inlet to the concentration at a point along the tower; Caustic: calculated requirements from knowledge of chlorinated lignin content temp., liquid level, pH of outlet (desired value 10.8); Bleach: calculated requirement, liquid level, output rate, output pH (desired value 6).