(695e) Experimental Analysis of Convective Drying of Paper and Board

In conventional multi cylinder drying of paper and board both conductive drying from steam heated dryer cylinders and convective drying by flowing air over the surface in the pockets are used. Pocket ventilation is a critical component in providing additional thermal energy and more importantly carrying away the evaporated water. Air temperature, velocity and humidity are critical process parameters influencing the convective drying process. An experimental setup was developed to study the convective drying of paper and board. Paper sheet moisture, temperature as well as air velocity, temperature and humidity were measured as drying proceeds. The instantaneous drying rate as well as convective heat and mass transfer coefficients were determined as drying proceeds. Experimental results as well as comparison to literature and commercial data are presented. The convective heat and mass transfer coefficients determined were compared to traditional correlations normally used in the modeling of paper drying. This data will be useful in process development and modeling and simulation of paper drying processes.