Studies On Slurrying Characteristics And Improving That Of Shenhua Coal Water Slurry

CWS (Coal Water Slurry) which makes use of coal instead of oil is a new kind of clean fuel and it has much merit. The use of CWS has great significance to the complex utilization of coal, petroleum saving and environmental protection. But CWS is a solid-liquid two-phase mixture and a complicated multistep dispersive suspension system, so there are many factors influencing the slurrying and rheological characteristics of CWS. Mainly includes following contents:Firstly, factors and mechanics which influence the slurrying characteristics of CWS are studied. There are many factors, such as the nature of coal (metamorphic grade, partical-size distribution, coal petrologic component, mineral substance, grindability index) , preparation technology (milling grinding method, equipment, intensity and time) , the size distribution and packing efficiency of coal, the type and quantity of addition agent, quality of water, temperature and so on.Secondly, the slurrying characteristics of Shenhua CWS are studied. Shenhua coals have much inherent moisture, much oxygenous functional group and their grindability index are all small, so there are many difficulties in preparing them to CWS. The maximum slurrying concentration of Shenhua CWS is always below 60%. This concentration is too small in practical application.Some effective methods to improve the slurrying characteristics of Shenhua CWS is put forward against the difficult reason. They are partical-size graded distribution, optimizational coal match, coal nature modified at low temperature, ultrasonic wave oscillating. Their action and microcosmic mechanics are studied by experiment.Afterwards, the slurrying characteristics of anthracite coal CWS are studied innovatively. Anthracite coals have little volatile, little inherent moisture, little oxygenous functional group and their grindability index are all high, so they are easy to prepare into CWS. The experimental results show that the maximum slurrying concentration of anthracite coal CWS is about 70%.Finally, based on the Fuzzing mathematics principles, it attempts to select the fuel characteristic together with the boiler running parameters to establish a new slagging propensity decision model. And it is combined with the running fact of WAN-FENG Power Plant, the results show that the model is more credible.