Effect of thermomechanical pulping variables on resin acid distribution

The effect of TMP pulping variables on resin acid distribution was investig ated using a pilot-scale TMP experiment. The statistical analysis of the ef fect-of pulping variables on the difference in distribution of individual r esin acids showed that refiner pressure and preheating time had a significa nt effect on resin acid distribution, whilst the amount of dilution water o nly affected the distribution of dehydroabietic and abietic acid. The plate gap had no effect on resin acid distribution. An increase of 11.7% in the distribution of abietic type resin acids, and a decrease of 10.5% in dehydroabietic acid distribution, was found during re fining. The distribution of pimaric type resin acids, on the other hand, de creased by only 1.3%.