A predictive model for the industrial air-impingement drying of resin impregnated paper

Abstract

Industrial drying lines of resin-impregnated paper are formed by contiguous furnaces where hot air jets impinge on the surface of the moving paper sheet. The number of production parameters that conditions the process is very high, making the final drying prediction, and the optimal adjustment of the production parameters, very complex tasks. A novel numerical tool for the fast prediction of this industrial drying is presented. The model, obtained from local mass and energy equations for the paper sheet, and fed with results from three-dimensional computational fluid dynamic simulations and thermo-gravimetric tests, determines the evolution of the paper weight along the line for any given combination of production parameters: paper velocity, furnaces air temperatures and mass flows, among others. The model is validated in an industrial line with 11 furnaces, 2 impregnation stages, and more than 150 adjustable operational input parameters, leading to relative errors in the predicted paper temperature evolution and final paper weight of less than 7% and 1%, respectively. Likewise, the model coupling with an optimization tool is also presented to show its capabilities on selecting the best production parameters for prescribed conditions, making the model a useful tool in the framework of the increasingly relevant role of mathematical models in industry.