| The blast furnace combustion zone is constituted by all of the tuyere zone,which not only could supply the heat and energy source for blast furnace production process, but also is the important reaction zone for stability operation of blast furnace, naming as the 'heart' for blast furnace. The temperature distribution and working state in combustion zone could directly determine the hot metal quality and hearth gas distribution, which are very important to ironmaking industry and could influence the stability state of blast furnace. Until now, there has no effective method or equipment used to detect the temperature distribution of blast furnace combustion zone by long-term way, leading to the working state of combustion zone still depend on the sample deduce based on the imagination, and the quantitative understanding for working state of combustion zone should be improved. In this paper, the main studies were based on the research and application of the temperature field in combustion zone of blast furnace.Firstly, the raceway adiabatic flame temperature calculation model was modified. The coke combustion percent in the raceway zone was determined by the real time calculation of the heat and mass balance of the blast furnace, which could ensure the calculation results of raceway adiabatic flame temperature coincide with the changing production situations. The trends and ranges of the above calculation results could provide a reference for designing the temperature detection prototype system and calculation model.Secondly, since the complex physical and chemical reaction were occured in the combustion zone, and also exsited high background noise, high dust and bad environment within the limited space of bright luminous heating. The combustion zone temperature field detection prototype system of blast furnace was built.Based on the characteristics of blast furnace combustion zone and the choice of hardware equipment, the temperature field of blast furnace combustion zone was calculated by colorimetric method.Thirdly, in order to improve the accuracy of the temperature detection in the combustion zone, the calibration and fitting of the blackbody furnace, the effective collection of the radiation zone, the removal of the image noise and edge detection were studied respectively. The results shown that the relative error was 0.53% when the calibration temperature range of the blackbody was under 1500 ?to 2100 ?. While radiation information of the blast furnace could be effectively collected by controlling the suitable shutter time and gain of CCD. In addition, the wavelet filter denoising method and the morphological edge detection method were used to deal with the noise of tuyere image and detect the image edge under different operation conditions.Forth, the combustion zone temperature field detection prototype system was applied in the 2000 m3 and 2500 m3 blast furnaces, and the results shown that the temperature field of the combustion zone is unevenly distributed in space and time.Moreover, the influence of the different PCI rate and all coke smelting were obtained, and the influence of the tuyere diameter, the PCI rate and the blast temperature on the temperature field were also obtained. The above results were similar to those of the previous research results and the modified raceway adiabatic flame temperature calculation model, thus the accuracy of the temperature test results was verified.Fifth, the indexes of the uniformity and activity for the local and the circumferential direction of the combustion zone were presented. Combined with the temperature field of the blast furnace combustion zone, the uniformity and activity of the local and circumferential directions of the combustion zone were studied, and the complete uniformity and activity evaluation system of the combustion zone were established. The results shown that the activity of the small volume blast furnace is larger than that of the large volume one, but its uniformity is lower than that of the large volume one. |
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