On-Line Pre-Heating/Drying of Paper Sheet with Gas-Fired Infrared Emitters, 2000 Papermakers Conference Proceedings

J. Seyed-Yagoobi, S.J. Sikirica, M.R. Ricks--Infrared (IR) radiation energy is not solely a surface-heating source, rather the radiant energy penetrates inside the medium, imparting volumetric heating while maintaining or improving heet quality. An attractive application for the IR emitter, besides the existing application in coated paper drying, is with on-line pre-heating and drying of uncoated paper.

A commercial paperboard machine is retrofitted and operated with IR heaters in multiple locations to investigate the on-line pre-heating/drying of uncoated paper sheet with gas-fired IR emitters. A theoretical model is developed to predict the increase in machine speed under various operating conditions with the use of IR heaters. The results indicate that the theoretical predictions are in close agreement with the machine data. More importantly, the theoretical predictions and the machine data show that significant increases in drying rates, thus machine speeds, can be achieved with appropriate installation of gas-fired IR emitters. As an example, for paper sheet with a basis weight of 94 lb/1,000 ft 2 , an increase in the machine speed of up to 36% is achieved with the operation of ne IR emitter in the press section, two IR emitters immediately prior to the drying section, and two IR emitters at the very end of the drying section.