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Effect of naphthalene series and lignin series dispersants on the sedimentation of coal particles and the stability of coal water slurry (CWS) were investigated using the multiple light scattering technique of Turbiscan Lab stability analyzer. The results show that coalescence between coal particles is the direct factor which causes differential sedimentation, and influences the stability of CWS. The variation of backscattering luminous flux is lower than 0.9%, and the CWS does not produce hard sedimentation in seven days. The average size of coal particle increases gradually along with the extension of standing time. The change rule is not obvious between average size and the ratio of compounded dispersants in the early standing time, but the average size decreases with the increase of additional amount of lignin series dispersants, TSI value shows a decreasing trend, and the stability of CWS increases gradually, which further confirmed the coalescence between coal particles is the main factor that influence the stability of CWS. Turbiscan Lab stability analyzer can realize real-time analysis on the stability and sedimentation process of CWS, and provide reliable data support for the selection of appropriate dispersant and its dosage. [ABSTRACT FROM AUTHOR]

In order to solve the problems of high energy consumption and high reabsorption, microwave dehydration technology of lignite was applied in this paper. The lignite with four different particle sizes from eastern Inner JVIongolia was treated by a self-developed microwave system under five different powers. The mathematical model for the moisture changes of lignite was developed and the relevant results were determined by finite difference method. And the computational results were in good agreement with the experimental results. The scanning electron microscope( SEIVI ) and low temperature nitrogen absorption method were applied to study the surface features and porous structure of coal samples. Distribution of oxygen-functional groups of carboxyl and phenol-hydroxyl was evaluated based on the chemical analysis results. Readsorption experiment in constant temperature and humidity with thermogravimetric analysis were performed to study the characteristics of readsorption and spontaneous combustion. It was found that the moisture after the readsorption of the lignite dried by microwave was far lower than 19. 87%, the moisture after the readsorption of the lignite dried by hot air, and the ignition temperature were increased to more than 295 °C from 275 °t. The results indicated that the interfacial stability of lignite is improved by microwave, and the dehydrated lignite is difficult to re-absorb water and combust spontaneously after microwave during. [ABSTRACT FROM AUTHOR]