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The effective thermodynamic analysis is quite necessary for proper system design performance and optimization of system processes. Energy is concerned with the quantitative evaluation of system processes. Nonetheless, exergy gives a qualitative analysis of the system processes. The present investigation deals with the study of exergy and energy analysis of the paddy drying processes in two tapered fluidized bed dryers having tapered angle 5° and 10° respectively and one cylindrical bubbling fluidized bed dryer. The energy utilization (EU) and energy utilization ratio (EUR) for various operating parameters such as inlet air velocity, mass of paddy, temperature, a spiral and cone angle are investigated. Similar to that, the exergetic efficiency and the rate of exergy destruction are also studied for the same operating parameters. The EU and EUR are found to have an increasing order when the inlet air velocity, temperature and mass of paddy increase. The trend of EU and EUR also increase with an addition of a spiral inside a dryer. The increasing cone angle of dryer have a similar impact on EU and EUR. Similarly, exergy utilization and exergetic efficiency also show an increment with the rise in inlet air velocity, mass of paddy, cone angle of dryer and temperature. Incorporation of a spiral inside a dryer improves exergy utilization and exergetic efficiency. Hence, conical dryer with higher cone angle is found to be the best option for drying.

Fluidized bed technology is a well-established environment friendly technology, by which energy can be generated through combustion and gasification techniques. It is widely prevalent today owing to its excellent heat transfer, mixing characteristics and compactness. The design and scale-up of the fluidized beds are vital to the enhancement of heat transfer and mixing characteristics. However, heat transfer characteristics play a key role in determining the combustion and gasification characteristics. CFD is a technique which helps to optimize the design and operation of fluidized bed combustor and gasifiers. Enhancement of computing speed and numerical techniques has led to CFD being used as a widely implemented tool to provide a bridge between laboratory scale and industrial study. In this chapter, a comprehensive review of CFD modelling and experimental study on the conical fluidized bed has been carried out. Primarily this chapter demonstrates probable future accomplishments and identifies trends and regions where further research is required.

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