Application of heat carrier particles in a fluidized bed dryer: Dimensionless modeling and GHG emissions

Abstract

AbstractDrying of agricultural products inherently is an energy intensive process. In the majority of drying processes, the energy for the air heating process is delivered by the steam, gas‐turbine, and combined‐cycle type power plants that run on the fossil fuels which in turn are responsible for global warming due to the greenhouse phenomena. The industry therefore is interested in the development of any energy saving measure in the drying process. This in turn reduces greenhouse gas (GHG) emissions. Optimization of the drying process for energy reduction by the mathematical modeling may provide means to accomplish this goal. In the present study, the drying of canola seeds in a fluidized bed dryer containing heat carrier particles was investigated. Drying kinetics was modeled using dimensionless groups and the GHG emissions in each process were determined and analyzed. Three temperature levels and four ratios of Heat Carrier Particle (HCP) to seeds were applied. The lowest specific energy consumption (least GHG emissions) was achieved when the air temperature was set at 60°C and the drying chamber was filled with a mass ratio of 0.5 of HCP to seeds. Values of R2, RMSE, and k2 obtained for the predicted and experimental data were 0.90, 0.017, and 0.00092 respectively.Practical applicationsIn the current investigation, specific energy consumption and GHG emissions in different drying conditions of canola seeds in a fluidized bed dryer containing heat carrier particles were calculated and compared. A dimensionless approach was used to establish a new model for drying of canola seeds in the fluidized bed dryer. Subsequently, a dimensionless equation describing the drying behavior of seeds was derived. This method while being a simple model, gives high precision data for all effective parameters in the drying process. Therefore, the establishment of a dimensionless model for the drying kinetics and investigation of GHG emissions in the present study can be useful for the development of Eco‐friendly drying methods for future usages in food process engineering.