Thermodynamic and environmental analyses for paddy drying in a semi-industrial dryer


In the present work, the first and second laws of thermodynamics were used to perform energy and exergy analyses for deep bed drying of paddy in a convective dryer. Also, the equivalent specific CO2 emission was assessed. Drying experiments were carried out at drying air temperatures of 40, 50 and 60 °C, and air flow rates of 0.008, 0.012 and 0.017 m3 s−1. Energy utilization, energy utilization ratio and energy efficiency were obtained to be in the range of 0.061‒0.1412 kJ s−1, 22.41‒46.81% and 4.37‒8.56%, respectively. Exergy loss decreased continually with drying time and the average values ranged from 0.019 to 0.081 kJ s−1. Exergy efficiency varied in the range of 32.44‒66.91%. Energy and exergy efficiency was improved at low temperature‒low flow rate and high temperature‒high flow rate, respectively. The results of environmental analysis declared that specific CO2 emission ranged from 3.83 to 8.42 kg \( _{{{\text{CO}}_{2} }} \) kg−1water where high temperature‒low flow rate drying air reduced the footprint.

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The authors are deeply grateful to the Language Center of Tiran Branch, Islamic Azad University, to finalize the manuscript.

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Correspondence to Mohsen Beigi.

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Beigi, M., Torki, M., Khoshnam, F. et al. Thermodynamic and environmental analyses for paddy drying in a semi-industrial dryer. J Therm Anal Calorim (2020).

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  • Semi-industrial drying
  • Rough rice
  • Energy utilization
  • Exergy efficiency
  • CO2 emission