A new moisture control method: Analysis of dynamic changes of temperature and moisture in coal particles during drying

The vapor–solid double split moving bed dryer compared to other dryer achieves the purpose of uniform drying of particles and higher drying efficiency. Aiming at theoretical blind spots and technical errors in this technology, a small drying device with stirring was set up in the laboratory to simulate the interface update of coal in the moving heating surface, and the dynamic changes of temperature and moisture during the drying period. Then the changes of coal particle characteristics after drying was tested and analyzed to evaluate the effect of these changes and storage conditions on water re-absorption during dry coal storage. The results indicate that interface update, drying temperature and particle size were three main factors that affect the drying rate of coal. The higher drying temperature will cause the shrinkage and collapse of the macropores and mesopores, this reduces the water re-absorption rate of dry coal during later storage in bunker. The reasonable stirring speed can not only meet the interface renewal rate of coal heating surface, but also protect the structure of large particles from being destroyed. Finally, the increase of ambient temperature and partial pressure of water vapor also can reduce the water re-absorption.