Radiotracer investigations of operation of a Kamyr installation for continuous production of pinewood cellulose

A series of radiotracer investigations of a Kamyr type installation for continuous cooking of pinewood chips was undertaken in order to optimize the operational capabilities of the digester. The whole work was done in two stages. The first one included radiotracer investigations of chips and liquor flow dynamics. La-140 and Na-24 were used as tracers for the respective two phases. Flow of the labelled material in the digester was detected and recorded by means of scintillation detectors localized on the external surface of the digester and pipelines. The detectors were connected with a microprocessor based on recording-calculating apparatus. Arrangement of the detectors was planned in such a way as to permit the determination of current position of the labelled material in subsequent technological zones of the digester. At the second stage, the radiotracer investigations concerned the final zone of the process - the countercurrent washing zone which physically occupies the lowermost part of the unit. The obtained results allowed to estimate intensity of the mixing process and, finally, to improve efficiency of the washing process. Eventually, the technological conclusions have been formulated. They resulted in important modifications of the cooking process. (author)