Research And Development Of Three-dimensional Temperature Field Simulation System For Rotary Kiln Of Iron Ore Oxidized Pellet

With technological development of BF iron making in China,"beneficiated material" has been attached to highly attention. Because pellets have uniform size and good permeability, pelletizing industry gets great development. At present, great-kiln is the main oxidized pellets production process in our country. In the actual production, pellet quality has a direct relationship with the temperature field in the kiln. However, as the rotary kiln is at spin state, and the flue gas and pellets are incessant movement, it is very difficult to measure the temperature distribution of gas and pellets online. Therefore, the research of temperature distribution inside the kiln is quite necessary.In this paper, on the basis of analyzing the movement of pellets and heat transfer process in rotary kiln, a three-dimensional heat transfer model of rotary kiln is established. The movement of pellets in the cross-sectional of rotary kiln is divided into the active layers and the ’plug flow’ region, and the velocity distribution of pellets in the cross-sectional is obtained. The three-dimensional heat transfer model is reasonably simplified, then an axial heat transfer model is used to describe temperature distribution of the flue gas, and a cross-sectional heat transfer model combined with the axial heat transfer model are used to describe the temperature distribution of pellets.According to the actual working condition, combined with the calculation formulas of various heat transfer coefficients, the heat transfer coefficients are amended. The values of correction value Δh can be determined by processing the infrared image in the kiln.The fourth-order Runge-Kutta method is used to solve axial heat transfer model and the finite difference method is used to solve cross-sectional heat transfer model, so the accuracy and stability of the model solution is ensured. The temperature distribution of pellets and flue gas in the kiln is obtained and the accuracy of the model calculation is88%.Using Visual Studio.Net, Matlab and Open CV as development tools, combining with the ADO database technology, the three-dimensional temperature field simulation system of rotary kiln for iron ore oxidized pellet production is developed. System software consists of the image processing subsystem, and the three-dimensional temperature field model subsystem. After using the system to production field, temperature distribution in rotary kiln is transparency. The system provides effective guidance for the oxidized pellets production, then the quality and production of pellets is improved, and the energy consumption is reduced.