共查询到18条相似文献,搜索用时 187 毫秒
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COREX流程主要使用块煤作为燃料,但仍需要加入一定比例的焦炭来支撑熔融气化炉内炉料,保证炉况顺行.块煤裂解形成的半焦和焦炭在熔融气化炉内的劣化程度对煤气流的透气性、渣铁的透气透液性和炉缸热量的分布等影响较大.利用风口取样技术取出风口焦试样,进行粒度分布研究、显微结构分析、透气性指数计算和热态性能测定,发现风口焦试样中大于10mm的较大颗粒多为入炉焦炭劣化所致,小于10mm的小颗粒多为块煤裂解所致;认为块煤挥发分热解后的产物会加剧焦炭的溶损反应,且块煤裂解半焦的反应后强度不及入炉焦炭,半焦在炉内的劣化是影响渣铁透气透液性的主要因素;最后结合对试验结果的分析,给出了降低COREX流程能耗的一些措施. 相似文献
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采用200 kg级炼焦炉对熔融气化炉主要使用的2种块煤进行了不同时间的半焦裂解试验,比较了2种块煤成焦后的粒度分布和强度变化,发现B煤在炼焦炉内粉化严重,随结焦时间的延长其粒度降解度一直在升高,而A煤降解度在达到最大值后开始下降.对比了2种块煤生成半焦的矿相微观结构,A煤生成的半焦主要以镶嵌结构和各向同性结构为主,而B煤生成的半焦主要以类丝炭和各向同性结构为主;2种半焦均含有未成焦煤.通过分析熔融气化炉内取出的风口试样中不同粒度的含碳物质其矿相微观结构,认为在炉缸内6.3 mm的颗粒由2种块煤裂解成焦后的粉化现象所引起,且B煤的粉化是主要因素. 相似文献
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相比于高炉风口喷吹富氧热风,熔融气化炉风口采用常温纯氧,使得炉内质量、动量、热量的传输以及煤气流分布等冶炼特征与高炉存在较大差异.通过建立熔融气化炉风口回旋区二维数学模型,系统考察熔融气化炉风口回旋区内速度分布、温度分布及气体组分分布的冶炼特征.结果表明:在气固相热交换及焦炭 (或块煤形成的半焦) 燃烧反应的综合作用下,熔融气化炉风口回旋区内气体温度迅速升高至3 500 K以上;此外,风口前端存在小规模的气体循环流动现象,故风口前端扩孔破损现象严重,进而导致非计划休风率较高;为减少此类休风现象,可适当额外喷吹富氢燃料性气体 (天然气、焦炉煤气),不仅能降低风口回旋区内气体温度,更可替代部分固体燃料,并充分发挥其中H2的高温还原优势,提升熔融气化炉冶炼效率. 相似文献
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目前,COREX流程中的熔融气化炉采用块煤代替焦炭作为燃料冶炼铁水。块煤在熔融气化炉中的反应行为对炉况的稳定顺行及铁水质量有着重要的影响。采用非等温热重分析法针对COREX用煤(大同煤)在热解过程中的失重速率、失重量以及影响因子进行了研究,分析了煤热解的整个失重过程,并讨论了不同升温速率对热解的影响。同时,考虑煤热解过程的不同特性,采用分段尝试法建立了煤热解过程的动力学理论模型,进而得到相应的动力学参数,有助于更好地分析块煤在气化炉内的热解行为,为COREX流程块煤的合理使用及采用风口喷煤技术提供理论依据。 相似文献
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休风时对COREX熔融气化炉进行风口取样,通过对风口试样的检测分析,用压差度的倒数表示炉内气相对料柱透液性的影响,用空隙度和温度强度的乘积表示炉内的渣铁液相对料柱透液性的影响,建立了表征熔融气化炉料柱透液性的公式.对两批风口试样的研究发现,熔融气化炉内不同位置风口试样的透液性指数与相应位置的滞留铁比呈现一致的对应关系.进一步分析了透液性指数的影响因素,发现在炉况不顺时,未反应完全的酸性脉石直接落入炉缸,导致沿风口径向部分位置的渣样熔化温度高于1500℃,影响了渣铁流动性.提出了增加料层厚度、采取合理的造渣制度、控制均匀的煤气流分布等技术措施,为改善熔融气化炉内料柱的透液性提供帮助. 相似文献
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为了研究高炉冶炼中焦炭的溶损行为,选用2种不同反应性的焦炭考察焦炭与烧结矿在不同温度下的耦合反应,研究不同温度下焦炭溶损与烧结矿还原的关系。研究结果表明,焦炭溶损和烧结矿还原的耦合反应随着反应温度的升高逐渐加剧,且焦炭反应性提高有利于烧结矿的还原。焦炭溶损率与烧结矿还原度呈正线性相关性,焦炭反应性(CRI)与拟合曲线的斜率k呈反比,而与截距b呈正比,截距可以表征焦炭对烧结矿的初始还原能力。耦合反应后焦炭的光学各向异性指数OTI增大、平均孔径和气孔率大幅增大,反应性较大的焦炭易于在焦炭表面溶损,反应后的孔径较大;而反应性较小的焦炭在反应过程中CO2气体易于扩散至焦炭内部均匀溶蚀各级气孔。 相似文献
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为了研究首钢高炉喷吹煤粉在风口前灰渣的熔点和高温黏度特性,采用灰熔点仪和FactSage软件对首钢几种常用喷吹煤种及混煤的灰熔融特性进行了对比分析,发现两种方法得到的结果具有相同的趋势。利用FactSage热力学计算软件,分析了1 600 ℃下京唐、迁钢两地喷吹煤灰在SiO2-CaO-Al2O3-MgO(w(MgO)=2%)四元相图中的位置,并对灰组分中SiO2、Al2O3、CaO、MgO、Fe2O3对液相线温度和对高温下煤灰黏度的影响进行了分析。研究发现,不同灰组分改变对煤灰液相线温度和黏度的影响是不同的,灰组分对液相线温度的影响相对复杂。高温状态下,首钢高炉煤灰下灰组分中Al2O3、Fe2O3、MgO质量分数增加有降低煤灰黏度的作用,而SiO2质量分数增加会增加煤灰黏度。混煤时应考虑不同组分对煤灰液相线温度和黏度的影响,通过合理控制灰组分达到控制风口前结渣的目的。 相似文献
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炼焦煤灰分是决定其价格的重要因素,为比较同一矿点煤种灰分对结焦性质的影响规律,对各炼焦煤进行黏结性、煤岩特征、灰分等分析并进行40 kg试验焦炉炼焦试验分析。研究表明,不同煤种炼焦煤灰分降低对黏结性改善幅度不同,黏结性较好的炼焦煤当其灰分降低时,黏结性改善不明显;黏结性较差的炼焦煤当灰分降低时,其黏结性改善较为明显;且不同煤种炼焦煤灰分降低时灰组成变化规律不同。不同煤种炼焦煤灰分降低时所炼焦炭其强度变化程度不同,黏结性较好的炼焦煤,当其灰分降低,所炼焦炭强度变化幅度不大;黏结性较差的炼焦煤,当其灰分降低时,所炼焦炭强度改善较大。 相似文献
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The interaction mechanism between the combustion products of pulverized coal injected and coke in the raceway of blast furnace was studied through thermodynamic calculation and experiments.The results in-dicated that additives significantly affected the melting property of coal ash in high temperature zone.Al-though the unburnt char, raw coal ash, and catalyzed coal ash failed to wet the coke surface, the wettabil-ity of the catalyzed coal ash on the coke was greater than that of the raw coal ash.Since the unburnt char had weak reaction with the coke surface, it showed little influence on the surface morphology of the coke. The interaction between the raw coal ash and the coke gave rise to the increase in the pore size on the coke surface.However, the raw coal ash only affected the coke surface and the entrances of the pores owing to its poor fluidity.After being melted, the catalyzed coal ash was expected to immerge into the inside part of the coke and then react with the coke, resulting in an expansion and increase of coke cavities.The raw coal ash and the unburnt char reduced the coke reactivity, while the catalyzed coal ash improved the coke reac-tivity.Thereinto, the coal ash containing Fe2 O3 exhibited a larger influence on the reactivity than that containing CaO. 相似文献
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It is difficult to distinguish tamping coke and top charging coke by conventional testing methods, such as cold strength, abrasion resistance, reactivity and strength after reaction. Some of tamping coke′s properties were even better than those of top charging coke, but from practical using effects of blast furnace, tamping coke was not as good as top charging coke. The reaction conditions were featured as high temperature, high alkali condition, intense reaction atmosphere and short time. Distribution of porosity in profile, microstructure and slag forming property of ash were analyzed and following conclusions were obtained. After alkali-rich reaction, there were obvious differences between top charging coke and tamping coke in microstructure. The porosity′s unevenness of tamping coke was greater than those of top charging coke, and tamping coke was with less and big pores in out space and inner part was dense with more throughout pores. After phase diagram and microstructure analysis, it could be obtained that ash forming characteristics of top charging coke were better than those of tamping coke, and top charging coke′s pores were blocked more seriously than those of tamping coke. From analysis of tuyere samples, it could be found that calcium content of ash in coke′s pores was small and it should belong to coke′s inherent ash; kalium (wK=28%) was unusually high in coke, so the situation of high alkali was close to real blast furnace reaction condition. 相似文献