The effect of water addition on the surface energy, bulk and flow properties of lignite

Abstract

In this paper, the relationship between angle of repose, surface energy and bulk and shear properties of different particle size distribution lignite pulverized coal with different moisture content was experimentally investigated. The dry sample and wet sample were prepared under relative humidity 0% and 90%. The interactions between coal samples and polar or non-polar gaseous probes were investigated by the surface energy test with an inverse gas chromatography (IGC) technique. The compressibility test and shear test were taken by the FT4 Powder Rheometer. The changes in bulk and flow properties of different particle size distribution samples were collected as a function of water content. The results show that water content plays a significant role on the packing and flow behaviors and surface energy of the dry and wet different particle size lignite pulverized coal. The IGC tests results showed that for the relative humidity 90% samples, the water was the interior water, which played a role of improving the flowability. In the end, a model was proposed to study the relationship between angle of repose and surface energy and flowability. The model could easily predict the relationship between angle of repose with wet and dry particles. This research will provide a better understanding on how water content affects surface characteristic and the flow properties of lignite particles and will benefit to optimize the relevant unit operations.