Structure And Properties Of The Four Duct Burners

The pollutants of cement industry threaten human health damagely and cause serious pollution to the environment.The coal that is Chinese leading coal energy distributes disproportion in China,the quantities in north of China is much bigger than that in south,and the quality in north is much better than that in south.In the grim context of national conditions and environments, the problem of cement industry is how to make use of the low quality coal to calcine cement effectively and reduce the harmful gas emissions of the cement industry. The development of an effective pulverized coal burner has become one of the important ways to solve the above problems. Although the pulverized coal burner in the system of Rotary kiln-burner is very small, it has significant impact to the major technical and economic indicators of the burning system, such as the output, quality, coal consumption, fire brick life expectancy, technological accidents, harmful gas emissions and the rate of operation.so the researchers all over the world are contributing themselves to looking for an efficient combustion and energy-saving and emission reduction burner.With the technology of CFD, the kiln shell cooling was the first time been considered in the hot state simulation and consequently the ideal distribution of temperature field was gotten. At the same time, the operating characteristics was changed and different simulation programs was designed,we explored the relationship between the structure and properties of the burner,and a lot of reference and guiding experience are discovered. Specific studies include the following:(1) Changing the operating conditions indicates that:Increasing the tornado track speed is conducive to enlarge the recirculation zone, which promotes combustion, but the speed should not be much higher, the kiln Paper is easily washed out. With the DC wind speed increasing, the rate of mixing up the pulverized coal rises and the flame is concentrable and powerful. (2) Changing the structrue of the burner indicates the following phenomenon:with the static speed, the primary air volume and the impulse increased whether reduce the aperture of the straight duct or add the number of holes, But the end speed of the coal decreased, which would result in the flame becoming long and powerless and making the burning time long.What is more, the remainder of the coal increased significantly, consequently adversely combustion.(3) The characteristics of static combustion of different grade of fuel are studied in mechanism with the TG.Under the conditions of TG, the soft coal is a high-grade fuel from the index of the combustion characteristics, because it showed a good fire, stable combustion and burn-off performance.The anthracite is a relatively low-grade fuel, although the rate of burning out is larger initial, it is lower latter, relative poor performance in the characteristic of ignition and stable and difficult to burn completely.(4) The situation of anthracite as the fuel is studied. Compared with soft coal, its high temperature zone peak increased 100℃, black flame became long and ignition point delayed under the same operating conditions. However, the burner has a very good rate of burning ember anthracite by analysing the situation of the remaining coal, and harmful gas emissions are also well below the average, which illustrate the adaptability of the burner.(5) The mechanism of formating NOx is studied,and the results of simulation are accordanced with that of theoretical.The formation of thermal-NO is closely relavant to the temperature,the quantities of NO increases exponentially with the temperature increasing.It is discovered that its export of NO is less than 400ppm through analysing the the average export volume and consequently the purpose of emission reduction is achieved,which indicates that the burner has unparalleled advantages.