QUANTITATIVE-ANALYSIS OF COMBINED IMPINGEMENT AND THROUGH AIR-DRYING OF PAPER

Models were developed and verified to represent the water removal rate data of the two components of combined impingement and through air dr ying process. Eight physically meaningful parameters were identified, determined, correlated and analyzed. The increasing rate period is ext ended by impingement water removal. Constant impingement water removal decreases linearly with through flow ratio at a fixed impingement exh aust air flow. Constant through flow water removal is independent of t he impingement air. Critical moisture content relates with through flo w ratio parabolically. The maximum through flow water removal rate dep ends on the slope of the paper temperature increase and the extent of the secondary increasing rate period which increases with paper basis weight and drying air temperature, but decreases with through flow rat io and initial moisture content.