High-intensity drying processes -- Impulse drying: Report 15 (final report). Production of linerboard on a pilot paper machine, subsequent commercial converting trials and preliminary economic assessment

In September 1998, 33{number_sign} liner was produced on the {number_sign}4 pilot machine under both single-felted wet pressing and impulse drying conditions. In October 1998, the pilot produced liner and commercial liner were converted to combined board and corrugated boxes at a commercial box plant. In January 1999, linerboard, medium, and combined board and box testing were completed. The pilot trials demonstrated that 33{number_sign} liner could be impulse dried at a reel speed of 380 m/min. Press dryness was improved by as much as 4 points, while CD STFI and CD ring crush were improved by more than 10%. Improvements to the smoothness of heated side of sheet were also realized. Commercial box plant converting trials demonstrated that impulse dried linerboard can be used to increase ECT and box compression strength by as much as 10%. As anticipated, print quality was found to be superior. A preliminary economic analysis was performed in which an impulse dryer would increase press dryness by 4 points and would allow the basis weight to be reduced by 10%. The economic model showed that the 4 points in dryness would translate to a 17% tonnage increase. Applying the 10% basis weight reduction resulted in an increase in productivity, on an area basis, of 30%. The pulp cost savings was found to outweigh any additional electric power costs