全氧條件下高爐高溫熱化學反應與能質傳遞協同原理

張欣欣 薛慶國 郭占成 王靜松 李俊

摘要：高爐作為目前主要的煉鐵工藝，經過上百年的發展，其碳耗已接近該工藝的理論最低值，很難再有大的突破。氧氣高爐作為一種新型煉鐵工藝，其可行性以及在節碳減排方面的突出優勢已經在理論上和試驗性高爐上得到了證實。該工藝由于采用全氧鼓風代替傳統的熱風操作，同時將爐頂煤氣脫除CO2后循環回高爐，使得爐內煤氣中的CO和H2含量大幅增加，從而導致爐內爐料的冶金性能也發生了變化。為了推進氧氣高爐工藝的工業化應用，對氧氣高爐煉鐵工藝進行了系統的研究。 本研究建立了一種氧氣高爐綜合數學模型，對不同氧氣高爐工藝流程進行模擬計算，并采用多種評價指標對氧氣高爐煉鐵工藝進行綜合評價，確定適宜的氧氣高爐工藝流程，為研究開發氧氣高爐煉鐵工藝提供理論基礎。 以氧氣高爐數學模型為基礎，在不同氣氛下分別進行燒結礦、球團礦和塊礦的低溫還原粉化實驗，分析氧氣高爐氣氛下含鐵爐料的低溫還原粉化特性。 利用高溫還原熔滴實驗裝置，進行不同操作條件下（傳統高爐和氧氣高爐）含鐵爐料的高溫軟熔特性實驗研究，討論氧氣高爐氣氛與傳統高爐氣氛下爐料軟熔特性的差異，初步探索氧氣高爐軟熔帶的形成及分布規律。采用程序還原及軟熔實驗裝置，通過設定升溫制度及分段改變煤氣成分來模擬燒結礦、球團礦及其混合礦在氧氣高爐與傳統高爐中的還原及軟熔行為，對爐料在氧氣高爐工藝條件下的還原及軟熔性質演變規律作出分析判斷。 以氧氣高爐數學模型為基礎，采用自制的單顆粒還原實驗裝置對球團礦在H2、CO以及兩者的混合氣氛中的還原行為及其交互作用進行了研究；采用顆粒模型與三界面未反應核模型相結合的方法對球團礦在CO/CO2/H2/H2O/N2混合氣氛下的還原行為進行數值模擬研究；用單顆粒焦炭溶損實驗裝置，分別對H2O、CO2以及兩者的混合氣氛中的焦炭的溶損行為及其交互作用進行了研究。 通過利用仿真模擬系統建立了氧氣高爐的數學模型對氧氣高爐的內部運行狀況進行了深入研究，分別采用粘性流方法和離散元方法對爐料下降運動進行數值模擬研究；建立了高爐風口回旋區的二維數學模型，對氧氣高爐中氣體的流動、煤粉顆粒的運動、氣體的傳熱（氣體間的傳熱和氣體與顆粒間的傳熱等）、顆粒的傳熱（顆粒之間的傳熱及與氣體間的傳熱等）、燃燒（煤粉和焦炭的燃燒）等過程進行了深入研究；通過建立一維和二維的氣固換熱與反應動力模型，對氧氣高爐內部的溫度分布、壓力分布以及不同相之間的換熱情況進行了深入了解。

關鍵詞：節能減排；全氧高爐；數學模型；爐料；數值模擬

The synergistic principle of Energy/mass transfer and high temperature thermochemical reaction under full oxygen blast furnace condition

Abstract：At present，traditional blast furnace with coke as main energy has been almost perfect in production efficiency and energy utilization， and it is difficult to realize the more energy saving and emission reduction by its technical progress in the traditional blast furnace. Oxygen blast furnace （OBF）， as a new iron-making process， has the outstanding advantages in carbon saving and low CO2 emission.Due to the operations of pure oxygen instead of the hot blast and recycling most of the top gas after CO2 removal， the content of CO and H2 in OBF increases significantly， which may also lead to the metallurgical performances of burden change. In order to promote the industrial application of OBF iron-making process， the systematic study of OBF ironmaking process was carried out. A comprehensive mathematical model of OBF was established. Many preliminary designs of OBF were simulated with the comprehensive mathematical model. The comprehensive evaluation of several different OBF process and traditional blast furnace has been made respectively. Through the evaluation， the most suitable process of OBF was identified. In order to analyze the low temperature reduction degradation behavior characteristics under the OBF atmosphere， low temperature reduction degradation experiments of ores have been carried on in different atmospheres which are based on the OBF mathematical model. The softening-melting properties of burden at different reducing atmospheres on the softening-melting properties of burden in OBF atmosphere were studied by using the facility of high temperature reduction-molten experiment. Using the programmed reducing and softening-melting experiment apparatuses， the reduction， softening and melting behaviors of sinter， pellet and mixture of both have been examined by simulating the conditions in traditional BF and typical OBF. It is preliminary founded the formation rule of cohesive zone under the OBF condition. The reduction behaviors of pellet in the atmospheres of H2， CO and mixture of both were studied by using the self-regulating reduction experiment apparatus of single particle. The reduction model of pellet， which was applicable to the research of the kinetic of non-isothermal reduction of pellet at the atmosphere of one or more gases of CO， CO2， H2， H2O and N2， was built based on the grain model and unreacted core model with three interfaces. The OBF internal operation conditions are studied by using the mathematical model.

Keywords：Energy saving and emission reduction； Full oxygen blast furnace； mathematical model； numerical simulation

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