For industrial paper drying, the entropy production from heat and mass transfer irreversibilities was determined by combining principles of irreversible thermodynamics with information from a dryer simulator. Transport irreversibilities depend on sheet and dryer characteristics. Entropy production for multi-cylinder paper dryer sections was compared for 5 paper machines, producing 3 grades of linerboard, 2 of newsprint. The three major contributions to entropy production were evaluated: entropy production for evaporation of water, for convective heat transfer between the sheet and ambient air, and for cylinder-to-sheet heat conduction. Effects on entropy production from paper basis weight and drying cylinder steam pressure were examined. (c) 2006 Elsevier Ltd. All rights reserved.