Process intensification studies in a fixed bed heat regenerator
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Date
2017-08
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G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand)
Abstract
Fixed bed regenerators are the heat exchangers used for transferring heat from hot fluid to cold fluid using solids as intermittent storage medium. The thesis presents the 3D, CFD modelling and analysis of unsteady flow through a fixed-bed regenerator. To account for the detailed flow complexities in porous media commercial Ansys Fluent 14.0 software was used. The predicted results of the temperature profiles were compared with the previous experimental results and a good agreement found between them. In order to carry out intensification of the process of heat transfer in the fixed bed heat regenerator, inlet boundary of the fixed bed heat regenerator was moved thereby simulating moving bed regenerator. Thus, moving bed heat regenerator is simulated without actually moving the solids of the bed. Temperature profiles along bed length and for different planes of regenerator bed are drawn with superficial air velocity of 0.382m/s, for both the fixed and moving bed regenerator.
It is observed that by moving the inlet boundary of the fixed bed regenerator temperature difference between the hot effluent gas and cold solids of the regenerator in the heat transfer zone increases resulting in faster heating of the bed. Pressure drop across the regenerator also decreases by moving the inlet boundary. It is observed that bed is heated up to a maximum inlet temperature of 400 °C in 102 minutes while in case of fixed bed it 123 minutes. Thus, the bed heats up 17 % faster in case of moving bed for the flow velocity of 0.382m/s.
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