Food Technology processes often involve complex cell matrix particles with a certain structure and porosity. In order to obtain the compounds of interest, extraction processes are held out in fixed bed reactors containing the porous particle material. The liquid flow is driven via pressure drop through the bed and will exit containing the extracted compounds of interest.
Several challenges arise in the modelling efforts of such extraction processes, specially at the smaller scale, regarding the complexity of the porous structure, the large quantity of compounds contained, and the multiphase flow in presence of gases. Moreover, the packed bed is a complex system as well; mainly because of the non-steady flow regime, the changing porosity, the large range of sizes and shapes of the particles, and the different scales of the whole process that have to be considered in the model.
Using an appropriate design of experiments, the fixed packed bed extraction process of espresso coffee, for instance, can be characterized, studying the impact of important process parameters such as volume flow, temperature, pressure drop and bed geometry on the homogeneity and yield of the extracted solution. Important particle properties such as shape, size, and porosity are investigated and incorporated to the analysis of the porous particle packed bed extraction process.
The objective of the integration from the different experimental results is to obtain an accurate model that could describe the extraction processes in terms of the relevant parameters and with it be able to influence the process efficiency and homogeneity.