Pulp and Paper Canada

Features Environment Sustainability
On-Line Measurement of Air Content in Pulp and Papermaking Systems. Part II: Applications to Defoamer Addition and to the Correction of a Consistency Transmitter


December 1, 2010
By Pulp & Paper Canada

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Mesure en ligne de la teneur en air des systmes de fabrication de ptes et papiers. Partie II : utilisation lors de l’ajout d’anti-mousse et pour la correction d’un convertisseur de concentration

Mesure en ligne de la teneur en air des systmes de fabrication de ptes et papiers. Partie II : utilisation lors de l’ajout d’anti-mousse et pour la correction d’un convertisseur de concentration

Abstract: We have previously described the use of a pressure-based, on-line air content probe in various commercial flotation cells used for the removal of ink and other hydrophobic contaminants from recycled pulps. In this second report, other uses of the air content probe are described. For example, the probe was installed in the foam tank of a recycling mill to correct the signal of a microwave consistency transmitter. Without this correction, predicted consistencies of flotation rejects were highly erroneous. We also describe how the air content measurement was successfully used to automatically control defoamer addition in the foam tank of flotation rejects. Finally, on-line measurement of air content in the vat of two kraft brownstock washers is shown to provide useful information on the effect of air on pulp drainage and washer effectiveness.

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Paper presented at 94th PAPTAC Annual Meeting in Montreal, February 5-7, 2008

Full manuscript available at www.paptac.ca.