Optimization of radiant-convective drying of a porous medium by design of experiment methodology

The major aim of this study was to improve tools to optimize the thermal drying of a porous medium. This article was devoted to the study of the radiant-convective drying of a material (cellular concrete) while respecting some thermal constraints. A numerical program had been previously developed and experimentally validated to model the thermal and hygroscopic behavior of the product. Design of experiments methodology (DOE) was used to obtain a behavioral reduced model that allows the operating optimums to be calculated quickly. Three characteristics of a drying operation were analyzed using response surface methodology: the drying time, the total energy used in the process, and the specific moisture extraction rate. The effects of all the drying parameters (initial moisture content, infrared power, air temperature, velocity, and humidity) were studied. The optimal conditions were determined for convective and infrared-convective drying.