Research On The Synergetic Influence Mechanism Of Fe₂O₃/CaO On Combustion Characteristics Of Injection Coal

Catalytic combustion is an important approach in coal utilization efficiency improvement.It is also of vital significance in the enhancement of coal injection combustion in blast furnace.Converter dust catalyzes coal combustion to a great extent,which is closely related to its components,Fe₂O₃ and CaO,two kinds of highly active catalysts.Therefore,in this thesis,the influence of converter dust on the catalytic combustion of pulverized coal injection was studied,the influence of interaction between Fe₂O₃-CaO on the catalytic effect of carbon-oxygen reaction was evaluated,and the interaction mechanism of Fe₂O₃-CaO during carbon dust combustion was also explored.The results are significant both theoretically and practically in broadening the utilization of metallurgical solid waste such as converter dust and developing low-cost and highly efficient composite catalyst.Based on the comparison of the chemical composition,surface morphology and pore structure of four kinds of converter dust,the influence of type,proportion and dispersion degree of converter dust on catalytic combustion of coal injection were studied in this thesis.Results showed that physical and chemical property of dust influences the combustion of pulverized coal injection to a great extent.Smaller particle size is linked with larger specific surface area,higher CaO content,and better catalytic effect.There is an optimum proportion in dust addition,and the greater the dispersion degree in coal,the better the catalytic effect is.By comparing the effect of CaO-Fe₂O₃?main active components in converter dust?composite catalyst on the catalytic combustion of carbon dust,the synergistic effect of composite catalyst on the combustion of carbon powder was studied.Results indicated that for Fe₂O₃/CaO composite catalysts,the catalytic effect appeared when the composite ratio was 2:8 and 4:6,and the inhibitional effect appeared when the composite ratio was 6:4 and 8:2.The interaction mechanism between Fe₂O₃ and CaO in catalytic combustion of carbon-oxygen reaction was clarified by study of chemical shift,reaction heat flux,surface morphology and pore structure of the composite catalyst during catalytic combustion and change of the binding state of the two components.Results showed that the deactivation of Fe₂O₃/CaO composite catalysts is caused by calcium ferrite fromed by sintering Fe₂O₃ and CaO.Higher combustion temperature and closer composite ratio to 7.4:2.6 lead to higher sintering degree of the catalysts and stronger inhibition on catalytic combustion.In practice,the catalytic effect of converter dust can be improved by reducing the temperature of composite catalysts or increasing the content of CaO.