AVT - Research - Research project

Phytoextraction is the subfield of solid extraction that deals with the task of product obtained from herbal materials. The industrial processes for the production of phytoextracts have so far been based mostly on empirical knowledge. The scientific design of extraction equipment is being impeded by the inherent complexity of the plant material. To facilitate the systematical research on solid extraction of various components under different conditions, a standardized laboratory-scale apparatus for phytoextraction has been developed. With this apparatus the study of the kinetics and equilibrium of the extraction process is possible. Moreover, different extractor setups like a fixed bed or a stirred-tank extractor can be characterized (Figure 1).

As a first step, suitable models from the literature are tested for calculating the mass transfer in solid particles. For distinguishing the best of the available models, the Model-Based Experimental Analysis (MEXA) is used. With this method the optimal experimental conditions are chosen so that the measured information in every experiment is maximized. In this way the model that describes the experimental results with a maximum accuracy is chosen out of the candidate models with a minimum of measuring effort. Currently different pre-treatment methods are investigated, which influence the properties of different natural raw materials and their extraction behaviour. Also, the choice of solvent or solvent composition is taken into account to determine the mass-transfer behaviour. The obtained results lead to a systematic heuristic, that leads to an adequate choice of pre-treatment and solvent choice for a given plant material. This heuristic together with the results from the standardized laboratory measuring cells and an optimal modelling, will lay the foundations for an accurate prediction of the extraction process in technical equipment.