Date of Award


Degree Type


Degree Name

Master of Engineering Science


Chemical and Biochemical Engineering


Dr Ajay K. Ray

Second Advisor

Dr. Jesse Zhu


In recent years, liquid-solid circulating fluidized beds (LSCFBs) are being applied as a reactor system in a number of new applications. This study focused on the modelling and multi-objective optimization of LSCFB system for continuous protein recovery process. A mathematical model was developed considering the protein adsorption and desorption characteristics, liquid-solid mass transfer and the hydrodynamics of the LSCFB, to predict the protein adsorption and desorption performance of the LSCFB system. The simulation results showed good agreement with available experimental data. Parametric sensitivity analysis showed complex interplay of various operational parameters over the system performance indicators. Moreover, the change in operating conditions in one column affects the performance of the other column as the two columns are interlinked. Multi-objective optimization of the LSCFB system at both the operation and the design stage were carried out using the model developed to determine the range of optimal solutions. Elitist nondominate sorting genetic algorithm with its jumping gene adaptation (NSGA-II-aJG) was used to solve a number of two- and three- objective function optimization problems. The optimization resulted in Pareto optimal solutions, which provides a broad range of non-dominated solutions due to conflicting behaviour of the operating and design parameters on the system performance indicators such as the protein production rate, the percent recovery and the amount of ion exchange particles required. Significant improvements were achieved, for example, for the same recovery level, the production rate at optimal operation increased by 33%, using 11% less solids compared to experimental results. In the design stage optimization, the performance of the system was further improved. This modelling and multi-objective optimization study is very general and can be easily extended for the improvement of LSCFB in other applications.



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