Numercial Simulation Research On Tailing Classifier And Experimental Investigation

At present, more and more direct-fired system were used in coal-fired power plant. Only tailing classifier was assembled on the outlet of mill in the system, and the pulverized-coal which came from the classifier were sent to the furnace chamber directly by the pipelines. So the separation efficiency and the fineness distribution are very important to safe, stable and economic combustion in the furnace. Numerical simulation technology is a method to analyze, compute and predict the flow field. With the help of this technology, the gas-solid two-phase flow inner the tailing classifier, the running character of the classifier and the efficiency and economy of the pulverized-coal preparation system were known and improved.Accord to the theory of numerical simulation, this paper presents a research by the CFD_FLUENT on the tailing classifier of the third boiler which belonged to Hunan zhuzhou power plant. And then, an experiment investigation was executed.Three pulverized-coal preparation systems were adequate with full load when Zhuzhou power plant was established. But sometimes four systems were not enough with over one year's running. For this, a plan that replaces the radial tailing classifier which was used before by axial one was put forward. At the same time, a comparison by FLUENT was executed, and the result shows that the resistance of the classifier could fell down by 46% and output of the pulverized-coal system could increase dramatically. This plan was received. For the axial tailing classifier, the characteristic of the dampers and the characteristic of separation were done with numerical simulation, and then, an experiment investigation was performed at field. The results of the numerical simulation showed that the best degree of the damper is 45 and its ventilation quantity which maintains 25 km3/h would be better. The feasibility and effectivity of numerical simulation was verified with the results of the experiment.With the help of computer, the research of numerical simulation to the tailing classifier with closed and complex geometry is very significant for knowing the inner gas-solid two phase flow field more deeply. And more reasonable advices could be supplied to the operators from the results of numerical simulation. Also the safe and economy of the unit could be improved.