張欣欣 薛慶國(guó) 郭占成 王靜松 李俊
摘要:高爐作為目前主要的煉鐵工藝,經(jīng)過(guò)上百年的發(fā)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(jié)碳減排方面的突出優(yōu)勢(shì)已經(jīng)在理論上和試驗(yàn)性高爐上得到了證實(shí)。該工藝由于采用全氧鼓風(fēng)代替?zhèn)鹘y(tǒng)的熱風(fēng)操作,同時(shí)將爐頂煤氣脫除CO2后循環(huán)回高爐,使得爐內(nèi)煤氣中的CO和H2含量大幅增加,從而導(dǎo)致?tīng)t內(nèi)爐料的冶金性能也發(fā)生了變化。為了推進(jìn)氧氣高爐工藝的工業(yè)化應(yīng)用,對(duì)氧氣高爐煉鐵工藝進(jìn)行了系統(tǒng)的研究。 本研究建立了一種氧氣高爐綜合數(shù)學(xué)模型,對(duì)不同氧氣高爐工藝流程進(jìn)行模擬計(jì)算,并采用多種評(píng)價(jià)指標(biāo)對(duì)氧氣高爐煉鐵工藝進(jìn)行綜合評(píng)價(jià),確定適宜的氧氣高爐工藝流程,為研究開(kāi)發(fā)氧氣高爐煉鐵工藝提供理論基礎(chǔ)。 以氧氣高爐數(shù)學(xué)模型為基礎(chǔ),在不同氣氛下分別進(jìn)行燒結(jié)礦、球團(tuán)礦和塊礦的低溫還原粉化實(shí)驗(yàn),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(shí)驗(yàn)裝置,進(jìn)行不同操作條件下(傳統(tǒng)高爐和氧氣高爐)含鐵爐料的高溫軟熔特性實(shí)驗(yàn)研究,討論氧氣高爐氣氛與傳統(tǒng)高爐氣氛下?tīng)t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(guī)律。采用程序還原及軟熔實(shí)驗(yàn)裝置,通過(guò)設(shè)定升溫制度及分段改變煤氣成分來(lái)模擬燒結(jié)礦、球團(tuán)礦及其混合礦在氧氣高爐與傳統(tǒng)高爐中的還原及軟熔行為,對(duì)爐料在氧氣高爐工藝條件下的還原及軟熔性質(zhì)演變規(guī)律作出分析判斷。 以氧氣高爐數(shù)學(xué)模型為基礎(chǔ),采用自制的單顆粒還原實(shí)驗(yàn)裝置對(duì)球團(tuán)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(jìn)行了研究;采用顆粒模型與三界面未反應(yīng)核模型相結(jié)合的方法對(duì)球團(tuán)礦在CO/CO2/H2/H2O/N2混合氣氛下的還原行為進(jìn)行數(shù)值模擬研究;用單顆粒焦炭溶損實(shí)驗(yàn)裝置,分別對(duì)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(jìn)行了研究。 通過(guò)利用仿真模擬系統(tǒng)建立了氧氣高爐的數(shù)學(xué)模型對(duì)氧氣高爐的內(nèi)部運(yùn)行狀況進(jìn)行了深入研究,分別采用粘性流方法和離散元方法對(duì)爐料下降運(yùn)動(dòng)進(jìn)行數(shù)值模擬研究;建立了高爐風(fēng)口回旋區(qū)的二維數(shù)學(xué)模型,對(duì)氧氣高爐中氣體的流動(dòng)、煤粉顆粒的運(yùn)動(dòng)、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(guò)程進(jìn)行了深入研究;通過(guò)建立一維和二維的氣固換熱與反應(yīng)動(dòng)力模型,對(duì)氧氣高爐內(nèi)部的溫度分布、壓力分布以及不同相之間的換熱情況進(jìn)行了深入了解。
關(guān)鍵詞:節(jié)能減排;全氧高爐;數(shù)學(xué)模型;爐料;數(shù)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
閱讀全文鏈接(需實(shí)名注冊(cè)):http://www.nstrs.cn/xiangxiBG.aspx?id=51670&flag=1