COMBINED IMPINGEMENT AND THROUGH AIR-DRYING OF PAPER - A COMPREHENSIVE MODEL

A comprehensive model predicts combined impingement and through air dr ying time and the contribution in water removal from impingement and t hrough flow. Experimental results verify the model. Prediction of dryi ng time reduction for combined impingement and through air drying from that of pure impingement drying was made using the ratio of through f low mass flow rate to the total inlet air flow rate. The parameters co nsidered included paper basis weight, drying air temperature, inlet ai r mass flow rate, paper initial moisture content, and two nozzle geome tries. Through flow can significantly reduce the drying time from that of pure impingement drying. The reduction of drying time from that of impingement to that of pure through drying is highly nonlinear. The m odel can help in parameter selection for a CITAD dryer design.