Impulse Drying of Paper: A Review of Recent Research

Impulse drying is a new process for drying paper that holds great promise for reducing the energy consumed during the manufacture of paper and similar web products. About half of the paper manufactured in the U.S. is comprised of heavyweight grades. Early attempts to commercialize impulse drying for these grades were complicated by the occurrence of sheet delamination. Research at the Institute of Paper Science and Technology (IPST) has demonstrated that ceramic coated press rolls have the potential for controlling heat transfer to the wet sheet, thereby allowing delamination-free impulse drying. Recent pilot dryer experiments demonstrate that heavyweight grades can be impulse dryed to 60% solids in a 40 millisecond nip, resulting in a 300 kWh per ton energy savings over conventional drying. With full implementation, at least 6,000,000 barrels of imported oil could be saved each year. These studies also confirm a 25% improvement to critical paper physical properties which will allow energy saving fiber substitution strategies. This paper reviews many of the key research findings that form the basis for plans to commercialize this important new technology