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Measuring Uniformity in Kraft Digesters Using Flow-Following Sensors

Dtermination de l’uniformit du fonctionnement des lessiveurs kraft l’aide de capteurs miniatures injectables dans la suspension

Dtermination de l’uniformit du fonctionnement des lessiveurs kraft l’aide de capteurs miniatures injectables dans la suspension

Abstract: Variability studies in kraft pulp digesters have been the subject of intense interest for many years. This paper reviews the various past approaches to measure this variability and then introduces a new method of its measurement: the SmartChip. This device measures and records the temperature directly within the digester as it flows with the wood chips during the kraft cook. Multiple SmartChips deployed in a single cook will then provide insight on the temperature variability and heat transfer mechanisms occurring within the digester. Moreover, by taking pulp samples in the vicinity of the SmartChip sensors, correlations between nonuniformity and temperature gradients can be established. The SmartChips have been tested in two laboratory batch digesters and as expected, little variability was observed in these small scale devices. These findings suggest that the Smart- Chip works well under the harsh conditions of the kraft cook and further work is warranted to develop the instrument for its use at the industrial scale.

Paper presented at the 2010 PacWest Conference in Sun Peaks, B.C., June 9-12, 2010.

Full manuscript available at www.paptac.ca.