| At present,petroleum coke and low ash coal have basically replaced charcoal with limited source in industrial silicon production.Petroleum coke has low ash content,high fixed carbon content,and its calorific value is about 1.5～2 times that of raw coal,so it is an ideal reducing agent in theory,but low-ash coal has high reactivity,low ash content,and low fixed carbon content.Separate petroleum coke or coal as a reducing agent has certain limitations.In order to give full play to their advantages,petroleum coke and low ash coal are used in industrial silicon production in a certain proportion is the current mainstream.In addition,in the industrial silicon production process,the actual carbon consumption is always higher than the theoretical carbon consumption,which is contrary to the current national "double carbon plan",and the actual carbon allocation is directly related to the physical and chemical properties of raw materials.Therefore,in order to reduce the direct carbon emissions of industrial silicon production process,it is extremely important to partially replace or strengthen the high-sulfur and high-coke reducing agent by biomass for industrial silicon production.The specific research content mainly includes the following points:(1)Collect actual production data and analyze the influence of reducing agents on the production process of different submerged arc furnaces through big data.The analysis found that the exergy efficiency of large-capacity silicon furnaces is higher than that of small furnaces,and it shows the potential for application in energy saving.By analyzing the influence of the components of petroleum coke and low-ash coal on the quality of industrial silicon products,it is found that the correlation coefficient between raw material consumption and industrial silicon quality is ≥98%.The impurity percentage increase ratio in 8.5 MVA furnace type is: coal >petroleum coke >silica,while the 12.5 MVA furnace type is the opposite.When the increase in unit consumption of fixed carbon is the same,the slight change of coal in the small-capacity furnace will cause a great change in the impurity content of the product.Coal in a large-capacity furnace has a relatively low impact on the quality of industrial silicon,but fluctuations in petroleum coke will have a greater impact on the quality of industrial silicon.(2)Biomass and petroleum coke were mixed with different ratios for natural fermentation and moldy.The reaction behavior of mixed carbon materials and the influence on the reaction behavior of silica carbon thermal reduction were analyzed by TG-DSC.It is found that there is an obvious synergistic effect in the pyrolysis process of mixed carbon materials.With the increase of biomass ratio and time,the pyrolysis temperature of fermented mixed carbon materials decreased by 32～47°C;the pyrolysis temperature of moldy mixed carbon materials decreased by 193～214°C.Silica reduction thermogravimetric analysis found that moldy carbon material reduced silica to Si C at 943°C,259°C earlier than fermentation conditions.Moldy conditions are more conducive to the preparation of carbonaceous reducing agents.There is a synergy between distillers’ grains as biomass and petroleum coke,but the increase in pyrolysis temperature may be due to the formation of glassy potassium silicate crystals on the carbon surface during the pyrolysis process.(3)Follow the steps in(2)to study the reaction behavior of natural fermentation and moldy by mixing the biomass and soal coal in different proportions.It was found that the pyrolysis temperature of the fermented mixed carbon materials decreased by38～55°C;under moldy conditions,it is reduced by 49～94°C.The effect of reducing silica by fermenting carbon is slightly better than that by moldy carbon.After mixing the corn distillers’ grains as biomass and soal coal,have a better carbothermal reduction effect on silica. |
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