PDF《博士学位论文公示材料》

16 empirical Gibbs free energy equations and

8 enthalpy data at 298K of the iron oxides reduction reactions are obtained;

The mechanism of hematite reduction reactions is dependent on the reaction temperature. It is two-step mechanism at low temperatures, while it is three-step mechanism at high temperatures, the transition temperature is 576? C for isothermal process and it is usually not 576? C for non-isothermal reactions because of the delay effect induced by different heating rate. The influences of non-stoichiometry on thermodynamic and kinetic of the iron oxides reduction reactioins are theoretically calculated and experimentally confirmed. (2) An application named Simulation of the Multi-interface Unreacted Core Model is programmed, and according to the single-interface shrinking core simulation, when the smelting intensity of oxygen blast furnace and traditional blast furnace is the same level, indirect reduction degrees of the blast furnace are 0.53, 0.64, 0.68, 0.73 and 0.81, corresponding to the blast oxygen enrichment of 22.2%, 40%, 60%, 80% and 100%. In other words, when the same indirect reduction degree is adopted by controlling the discharge speed, the more oxygen of the blast furnace is enriched, the less reduction time lasts, and the utilization coefficients are 2.0 t・d-1 ・m-3 , 2.83 t・d-1 ・m-3 , 3.26 t・d-1 ・m-3 , 3.84 t・d-1 ・m-3 and 5.02 t・d-1 ・m-3 respectively. (3) A program named Unsteady resolution and multi-objective optimization of the TGR-OBF process is developed. Taking advantage of the program, the calculation results of the traditional blast furnace process are gained: the coke rate is 337kg/t, the PCI rate is 198kg/t, the carbon consumption is 425kg/t, dry fuel rate is 523kg/t, the first heat loss is 4.10%, the thermal reservation temperature is 980? C, the theoretical combustion temperature is 2032? C, the two kinds of energy consumptions are 519kgce/t and 377kgce/t respectively, the ―4― two kinds of exergy consumptions are 15.63GJ/t and 11.96GJ/t respectively, exergy efficiency is 77%. (4) Influences of six operational parameters on carbon consumption and first exergy consumption of the TGR-OBF process are investigated by three-dimensional optimization. As an example, the three-dimensional function of carbon consumption with respect to blast oxygen content and blast temperature is non-linear, and the direction of cutting down carbon consumption arcs opposite to the origin. When the blast oxygen content is fixed, the carbon consumption decreases with raising blast temperature;

when the blast temperature is fixed, the carbon consumption firstly rises to a climax and then goes down non-linearly with increasing blast oxygen content. In the three-dimensional system of blast oxygen content-blast temperature-first exergy consumption , the profile of the three-dimensional picture is similar to the one mentioned above. The minimum of first exergy consumption is located in the region of high blast temperature and high blast oxygen content. (5) The least carbon consumption of the optimized processes is 289kg/t, which is less than the theoretical least carbon consumption of the conventional blast furnace. The technical and economic indexes of the comprehensive optimized TGR-OBF process are calculated: the coke rate is 150kg/t, the PCI rate is 237kg/t, the carbon consumption is 300kg/t which is less than that of the traditional blast furnace by 125kg/t, the two kinds of exergy consumptions are 12.34GJ/t and 11.96GJ/t respectively, where the first exergy consumption is 3.29GJ/t less than that of the traditional blast furnace, and the second exergy consumption is the same as the data of traditional blast furnace, exergy efficiency is 85%. Additionally, because the huge amount of CO is recycled in furnace and the large amount of CO2 is absorbed by VPSA, the CO2 emission of this process is just 71m3 /t, which means the new TGR-OBF process cuts down about 90% CO2 emission. That the relevant pollutants are reduced largely because of the less coke usage is simultaneously attractive. ―5― 论文主要创新点 (1) 通过文献调研、理论计算和实验研究,对铁氧化物逐级还原反应的热力学和动力学进行基础 理论研究.从热力学和动力学两个层面,阐明非化学计量比对铁氧化物还原过程的影响,丰富炼铁理 论. (2) 根据三界面未反应核模型,充分考虑时间、气氛、压力及活化能等对氧气高........