ABSTRACT

Operation of the pneumatic conveying system for drying coal was influenced by many parameters, in particular, gas velocity, gas temperature, coal residence time, and coal particle size. In this study, the pneumatic conveying drying system was simulated for drying wet coal. Numerical studies were conducted to examine the effect of these parameters on drying coal. As the gas temperature increased, the drying rate of wet coal increased. In addition, coal drying increased with an increase of coal residence time. Particle size is one of the most important parameter on moisture removal efficiency of the pneumatic conveying dryer. The moisture removal increased in short drying time with a decrease in particle size due to the large surface area.

INTRODUCTION

Pneumatic conveying drying is the combination of heat and mass transfer between hot gas and wet particles. This technique has been widely used in various industry processes, due to the reasons of maximum efficiency, minimum gas flows and power consumption, improved product quality and increased workplace safety. In pneumatic dryer system, a wet particle is rapidly dried as it comes into contact with hot gas, and the atomized feed sample travels concurrently with the drying-gas. Operation of the pneumatic conveying system for drying wet particles was influenced by many parameters, in particular, gas velocity, gas temperature, particle residence time, and particle size. Many experimental and numerical studies of a pneumatic conveying dryer have focused on an effect of these parameters on drying rate of wet particles. As for experimental approach, Yamazawa et al. (1972) presented an improvement of rice physical properties using a pneumatic conveying dryer. Tandano et al (1981) investigated pneumatic conveying dryer operation and clarified the drying time experimentally. Baeyens et al. (1995) presented a design procedure to predict moisture and temperature profiles in a pneumatic dryer.

This content is only available via PDF.
You can access this article if you purchase or spend a download.