Innovative Fluidization Technologies for Green Processes

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INTRODUCTION: Fluidized bed drying is widely used for drying processes in the pharmaceutical, fertilizer, food, agriculture, and petrochemical industries. However, this energy-intensive process requires design and operation solutions to minimize its energy consumption and environmental footprint. Fluidized beds have been used as effective vehicles to convert biomass into green energy. Particle mixing and segregation plays an important role in the overall process efficiency of fluidized bed reactors. This research program will develop innovation solutions to enhance the drying performance by introducing pulsed gas flow. In addition, synchrotron-based X-ray imaging will be used to reveal new information within fluidized beds to further improve energy conversion. OBJECTIVES: Specific short-term objectives are to: 1) Investigate the effect of pulsed flow on bubbling and drying behaviour of pharmaceutical particles in a fluidized bed dryer; 2) Develop mathematical models and numerical simulations of drying processes using computational fluid dynamics (CFD); and 3) Investigate mixing and segregation of binary mixtures involving biomass materials in fluidized beds via novel synchrotron-based X-ray imaging techniques. METHODS: Efforts will first be placed on investigating drying and bubbling behaviour of pharmaceutical powders in a pulsation-assisted fluidized bed dryer (Objective 1). Drying experiments will be conducted in a conical fluidized bed dryer equipped with an electrical capacitance tomography (ECT) system available at the UofS. Drying rate will be measured and correlated with bubbling data collected. CFD, an advanced modeling and numerical simulation tool, will be employed to simulate the drying process with/without pulsed flow (Objective 2). Both the drying rate and bubbling behaviour determined from the experiments will be used to validate numerical simulations. In parallel, synchrotron-based X-ray computed tomography (CT) will be employed to investigate mixing and segregation of binary mixtures involving biomass pellets in a fluidized bed (Objective 3). The comprehensive knowledge obtained will improve operation of a fluidized bed gasifier. IMPACT: The proposed research program will produce comprehensive knowledge of enhanced fluidized bed drying processes for pharmaceutical applications with pulsed gas flow. Based on the outcomes of the work, an optimized operation envelope will be provided to achieve a reduction in energy use and environmental footprint associated with this unit operation. Detailed information about mixing and segregation under various operating conditions will inform efficient operation of fluidized bed reactors for various thermal processes with an aim to produce clean energy from renewable biomass resources, particularly pellet fuels. My long-term objective is to expand the research program to benefit other drying processes in fertilizer, food, mining, and agricultural industries.