Fuzzy modelling of hydrodynamics and mass transfer of drops in a rotating disc contactor column

Abstract

Rotating Disc Contactor (RDC) column is one of the important equipments for separation process, because it gives high performance and is more efficient among equipments for solvent extraction. Over the years, researchers and engineers are designing and building models of hydrodynamics of drops and mass transfer to interpret the performance and to increase the efficiency of the RDC column. In this research, the main aim is to develop and design models of hydrodynamics and mass transfer of drops that are capable of work with any design of RDC column based on the experimental data and fuzzy modelling. Firstly, the Sauter mean diameter is calculated based on the flow rate of dispersed phase and Mamdani fuzzy model. Secondly, the fuzzy model based on optimal interval technique (FMBOIT) is established to predict models of the hydrodynamics of drops such as, mean number of daughter drops, probability of drop breakage, Sauter mean diameter and hold-up of dispersed phase from experimental data. Then, these models and beta distribution are incorporated to develop the forward model of drop size distribution, which is used to obtain the drop size distribution along RDC column. Besides the forward model, the inverse model of drop size distribution is constructed based on the optimization technique that determined the number of drops at bottom stages using the number of drops at top stages. The last model is the mass transfer model, which depends on the forward model of drop size distribution for calculating the amount of mass transfer from the continuous phase to the dispersed phase. In addition, the mass transfer model allows the usage of either the terminal or the characteristic velocity of drops which determines the lifetime of drops between compartments. All the models are developed based on three phases. Phase one is the literature review and problem formulation. Phase two is the design and development of the proposed models. Phase three is implementation, verification and validation of proposed models from phase two. Most of these models give less error when compared with simulation data of previous researchers against experimental data. Furthermore, the new mass transfer model allows parameters such as the height of the compartment, the number of stages or the diameter of the column to be changed at the same time. Thus, this new model is a powerful model for predicting the performance and design of RDC column.