Energy and exergy analysis of fluidised bed citric acid dryers

Fluidised bed dryers are widely used for removing all or a portion of moisture in products in food, agricultural and chemical industries. In this work, a comprehensive first and second law analysis on fluidised bed dryers employed in acid citric production factories are accomplished. To have an accurate simulation, fluidised bed dryer of Jovein factory, as the biggest citric acid factory of Middle East, has been chosen as the case study of this work. In the end, the origins of exergy destruction and energy wastes are recognised and some proposals are presented for optimising the thermodynamic performance of the dryer. Taking the results of this study into account, it is finally found out that reducing drying air flow rate and temperature, decreasing the outlet product humidity and lower heat loss rates enhance both energy and exergy efficiencies.