Title: Energy and exergy analysis of fluidised bed citric acid dryers

Authors: Mahdi Deymi-Dashtebayaz; Ahmad Arabkoohsar; Farid Darabian

Addresses: Department of Mechanical Engineering, Hakim Sabzevari University, Sabzevar, 9617976487, Iran ' Department of Mechanical Engineering, Azadshahr Branch, Islamic Azad University, Azadshahr, 4961789985, Iran ' Department of Mechanical Engineering, Hakim Sabzevari University, Sabzevar, 9617976487, Iran

Abstract: 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.

Keywords: fluidised bed dryers; citric acid crystals; energy analysis; exergy analysis; sensitivity analysis; thermodynamics; acid citric production; simulation; case study; exergy destruction; energy waste; optimisation; thermodynamic performance; air flow rate; temperature reduction; outlet product humidity; heat loss rate; energy efficiency; exergy efficiency.

DOI: 10.1504/IJEX.2017.083169

International Journal of Exergy, 2017 Vol.22 No.3, pp.218 - 234

Received: 08 Apr 2016
Accepted: 03 Sep 2016

Published online: 21 Mar 2017 *

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