Pulverizing system and process for reducing ash and improving quality of circulating materials in medium-speed coal pulverizers in coal-fired power plants

Abstract

The invention discloses a pulverization system and process for reducing ash and improving the quality of circulating materials in a medium-speed coal mill of a coal-fired power plant. The grading particle size of the built-in pulverized coal classifier and the secondary classification operation with the external cyclone classifier realize the discharge of the circulating material in the coal mill, and remove the continuously accumulated ore in the circulating material through the pulsating airflow separation bed. The material components can reduce the internal circulation rate of the mill while ensuring the quality of qualified pulverized coal is improved. Utilizing this process can not only achieve multiple purposes such as improving the quality of qualified pulverized coal, improving boiler combustion efficiency and reducing pollutant emissions, but also can effectively reduce the internal circulation rate of the mill, reduce equipment wear and energy consumption, and finally realize the coal pulverization of power plants The system "grinding-classification-sorting" is integrated.

Description

technical field [0001] The invention relates to a pulverizing system and process for reducing ash and improving the quality of circulating materials in a medium-speed coal pulverizer of a coal-fired power plant, so as to realize reducing ash and improving the quality of coal during the grinding process and before combustion. [0002] technical background [0003] Most of the coal used in power plants is low-quality raw coal with high ash content, which has high gangue content, large ash discharge, low calorific value and poor grindability. Raw coal needs to be ground many times to meet the particle size requirements of qualified coal powder, resulting in the quality of the circulating material inside the mill being much greater than the output of the coal mill. According to research, the circulation rate in the mill (the ratio of the mass flow rate of the circulating material to the output of the mill) is as high as 8 to 10 times. A large amount of coal-based minerals with h...

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Problems solved by technology

However, since the interior of the coal mill is a high-temperature and high-pressure closed operating system, if the interception sampling of circulating materials is to be realized in the mill, it is necessary to complete the dynamic balance of pressure and temperature inside and outside the sampling node, and to simultaneously adjust the working parameters of other parts of the mill , leading to greater difficulty in the diversion operation of circulating materials under actual working conditions

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