Applications of radioactive tracers in the study of throughflow chemical reactors. XIII

Pulse responses were measured of the first four bleaching stages of the CEHDED bleaching plant producing paper pulp and of five stages of the CEDED bleaching plant producing dissolving pulp. The transition characteristics of individual stages and of the whole unit comprising stages I-II, I-III and I to V or VI were calculated. The method is described of using measured data for the prediction of transition characteristics for outputs other than for which the pulse responses have been measured and the use of pulse response data is demonstrated for the evaluation of paper pulps (based on chlorine consumption or variations of the kappa number in the first chlorination degree) or for the evaluation of dissolving pulps on the basis of ''viscosity changes'm in the fourth stage (i.e., in hypochlorite bleaching). (author)