Energy Consumption of a Pilot-Scale Spray Dryer

Abstract

Factors affecting the energy consumption of a pilot-scale spray dryer have been studied. The feedstock employed was instant coffee solution (50–150 gl⁻¹). Its feed rate ranged from 0.83 to 1.9 mls⁻¹ and the inlet air temperature from 473–533 K. The specific energy consumption E _s (3,000–5,500 kJkg⁻¹) decreased with increasing feed rate and temperature difference across the dryer and increased with solids concentration. Values of E _s obtained were consistent with Baker and McKenzie's^{[ 10 ]} adiabatic dryer model. The thermal loss factor η decreased with increasing evaporation rate. Attempts to correlate product moisture content with the operating variables met with limited success.

Keywords:

• Energy consumption
• Experimental
• Product moisture content
• Spray drying

ACKNOWLEDGMENTS

The authors acknowledge with thanks the financial support provided by the College of Graduate Studies, Kuwait University. Thanks are also due to the Kuwait Institute for Scientific Research for permitting the authors to use its pilot-plant facilities.