The Viscosity Properties Of Coal Slurry And Its Experimental Investigation

Coal slurry is the product in the process of coal washing, abandoned largely and causes serious environmental pollution and resource wastes. Coal washery transports the slime into boiler to generate electricity, because of a certain calorific value. Pipeline transportation is the best way to transport slime. Because of high viscosity, it always binds on the pipeline in the process of transportation that hinder transport efficiency. The usual way is to increase the water content to reduce viscosity, but it may affect combustion efficiency. The study of slurry viscosity properties has significant meaning to recycle. This paper tests the influence of water content, temperature, standing time and particle sizes on viscosity. The relationships of factors and viscosity are fitted. And, the corresponding analysis are deduced theoretically. The research contents and conclusions are as follows:1. The influence of water content on slurry viscosityCoal slurry viscosity declines with the increasing of water content. It shows that the water content has a great influence on viscosity. A relatively smaller change of water content has a larger effect on viscosity when water content is low. The water content should be controlled as possible, when pipeline transportation.2. The influence of temperature on slurry viscosityThe slime viscosity decreases with the increasing of temperature. When the temperature is between 0～35℃, viscosity declines greatly. As the temperature rises, the range of change decreases. Temperature has an obvious impact on viscosity at lower water content. The temperature of pipeline or coal slurry can be increased considerably when transportation.3. The influence of standing time on slurry viscosityThe slime viscosity increases with the increasing of standing time. Viscosity increases quickly the first three days. It changes more and more slowly with the extension of time and becomes constant five days later. So the coal slurry produced by coal washery should be transported by pipeline as soon as possible and short the dumping time.4. The influence of particle sizes on slurry viscosityThe coal slime viscosity increases with the decreasing of particle size. Particle size has a great influence on slurry viscosity. The decreasing of particle size can cause the viscosity multiplying; The addition of fine particles reduces viscosity of coal slurry. And, the viscosity rises gradually with the increasing of fine particles. Viscosity have relatively large difference in different grading.There is a optimum proportion of grain size that makes the viscosity lowest.5. The influence of slurry component on viscosityThe results of XRF show that Al, Si, S and Ca are also high in content besides the major elements of C and O. Those elements make up a lot of inorganic salt and ash that make the viscosity high and unstable; The viscosity of slime B is lower than A under the same conditions. Because the microelements, inorganic salt and ash are relatively fewer. This indicates that the component is a factor of influencing viscosity.Water content is the main factor of affecting its viscosity in the process of pipeline transportation of coal slurry. A few percentage changes can cause large fluctuations of viscosity. Hence, the water content should be controlled as soon as possible without affecting combustion efficiency. In addition, the temperature should be raised appropriately and the standing time shortened.