FORFARANDE FOR REGLERING AV GRENSVISKOSITETEN HOS SULFITMASSA

摘要

A process for accurately controlling the intrinsic viscosity of sulfite pulp at the termination of a digestion operation comprising predetermining the duration of digestion time required to obtain a given pulp intrinsic viscosity for a range of initial weight ratios of combined SO2 to wood, determining during the digestion operation the initial weight ratio of combined SO2 to wood by measuring the rate of change of absorbance in the digestion cooking liquor and terminating the digestion operation at a time corresponding to the predetermined time required to obtain the given pulp intrinsic viscosity at the aforesaid combined SO2 to wood ratio.