Energy Performance of Convective Dryers

Abstract

Following background information on energy efficiency measures, this paper presents the methodology and calculation results for energy performance of several industrial dryers quantified in terms of the specific energy consumption and compared to the results obtained from the Baker and McKenzie's adiabatic dryer model for convective dryers. Examples of performance assessment are given for an indirectly heated spouted bed dryer with inert particles and a spray dryer with integrated fluidized bed. Because the energy performance determination is based on temperature and humidity of the ambient and exhaust air, the calculation method is also given for gas-fired direct dryers represented by a natural-gas heated pneumatic dryer for which combustion air and generated water vapor have to be accounted.

Keywords:

• Convective dryers
• Drying
• Energy efficiency
• Fast spouted bed
• Hybrid dryer
• Pneumatic dryer
• Specific energy consumption

ACKNOWLEDGMENTS

The constructive comments of Prof. C. G. J. Baker from Kuwait University are greatly appreciated.

Notes

*Value taken for calculations in the case of fluctuating parameter.

^a One nozzle.

^b Two nozzles.

1, 2, and 3 indicate air streams as shown in Fig. 3.

^a One nozzle.

^b Two nozzles.