Drying Characteristics of Barley Grain Dried in a Spouted-Bed and Combined IR-Convection Dryers

Abstract

A study was performed to determine the drying characteristics and quality of barley grain dried in a laboratory scale spouted-bed dryer at 30, 35, 40, and 45°C and an inlet air velocity of 23 m/s⁻¹, and in an IR-convection dryer under an infrared radiation intensity of 0.048, 0.061, 0.073, and 0.107 W cm⁻² at an air velocity of 0.5 m/s⁻¹. The results show that the first, relatively short, phase of a sharp decrease in the drying rate was followed by the phase of a slow decrease. The time of barley drying depended on temperature of inlet air in a spouted-bed dryer and on radiation intensities in an IR-convection dryer. Barley drying at 45°C in a spouted-bed dryer was accompanied by the lowest total energy consumption. The average specific energy consumption was lower and the average efficiency of drying was higher for drying in a spouted-bed dryer. The effective diffusivities were in the range 2.20–4.52 × 10⁻¹¹ m² s⁻¹ and 3.04–4.79 × 10⁻¹¹ m²/s⁻¹ for barley dried in a spouted-bed and in an IR-convection dryer, respectively. There were no significant differences in kernel germination energy and capacity between the two drying methods tested.

Keywords:

• Barley
• Bed hydrodynamics
• Diffusivity
• Drying rate
• IR-convection dryer
• Quality attributes
• Spouted-bed dryer
• Time of drying

ACKNOWLEDGEMENTS

The authors are grateful for the financial support provided by the Ministry of Scientific Research within the framework of grant no. 2 P06T 062 27.

Notes

Means with the same letter in the same column are not significantly different (p ≤ 0.05).

Means with the same letter in the same column are not significantly different (p ≤ 0.05).