| Rapid development of metallurgical industry and gradual improvement of smelting technology exacerbate industry dilemma. Faced severe market situation,blast furnace turned to be large-scaled to lower production costs and reduce environmental pollution. In daily operation of modern large BF, burden profile and variation of ore to coke ratio formed by burden distribution are crucial factors of gas distribution, chemical reaction, heat, mass, momentum transfer and stable production of the blast furnace. So reasonable burden profile formed by burden distribution exerts important impact on rational gas distribution and stable furnace condition.Based on previous studies, a mathematical model has been developed for large BF to predict burden profile which is difficult to monitored directly. Burden distribution process and mechanism were studied and operation data and experts experience were also considered in the model. The mathematical model build according to burden trajectory mainly included three parts: burden movement law,formation of burden profile and variation prediction of ore to coke ratio. Burden flow in the throttle valve, on the chute and drop to the furnace in the whole motion.Formation of burden profile consists of formation mechanism and profile correction.According to built mathematical model, simulation model was developed through Visual C programming. Based on given charging system, falling point,burden profile and variation of ore to coke ratio in radial direction could be calculated in this model. To provide technical support for the change and optimization of charging system, burden distribution in BF was characterized quantitatively and burden profile and variation of ore to coke ratio were calculated and displayed in the model. Burden trajectory was simulated and blow-in distribution parameters were calculated. The simulated results by the model were in good agreements with detection. Simulation model was also optimized reasonably for the improvement of prediction accuracy based on real-time monitoring technology, such as infrared imaging system and cross beam temperature measuring technology.Inputting daily distribution parameters of 8th BF into the model, simulationresults are consistent with detection. Changing burden charging matrix, the calculated results showed that ideal flat boss type of burden profile was more likely to expand under large chute inclination difference and big inclination. Also increasing inner distribution of coke(charged matrix changed from C3322298765O3332298765toC332222987654O3332298765) will improve center permeability and aggravate edge permeability. And it results in increase of center and decrease of edge in the top. The variation of ore to coke ratio substitute approximates the trend of cross bean measuring temperature statics. |
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