矿物质负载方式对焦炭溶损反应的作用研究

比较了1 1种氧化物以添加和吸附两种方式负载到同种焦炭中对焦炭溶损反应作用的区别,并从催化作用、矿物质在焦炭中的分散方式和矿物质对焦炭显微结构作用三方面分析了导致作用不同的机理.同种矿物质无论以何种方式负载对炭的催化作用是相同的.吸附矿物质主要是均匀分散在焦炭表面,而添加矿物质则部分被炭基质包裹,两种方式提供的催化表面是不同的,添加到煤中的矿物质还可以通过对焦炭结构产生影响而导致对焦炭反应性的作用.     

煤中矿物质对焦炭光学显微组分的影响

将一些煤中常见矿物质配入煤中炼焦,考察了不同矿物质对所得焦炭光学显微组织的影响．研究结果表明,不同含量的矿物质对各类光学组织的含量有不同程度的影响．随矿物质含量的增加,各向同性组织与细粒镶嵌组织含量之和（I＋Mf）增大,光学各向异性指数（OTI）减小;不同矿物质对显微组分影响从大到小的排列顺序为Fe,Ba＞Ca＞Mg;而且同一矿物质对不同焦炭的影响程度也不同．高挥发分的芦岭煤受矿物质的影响较小,而粘结性较高的古交煤受矿物质的影响较大．     

灰成分对焦炭热性质影响的研究及应用

分析了焦炭灰分的组成及灰分中矿物质对焦炭热性质的影响方式。介绍了安钢通过在焦炭中添加对焦炭溶损反应起负催化作用的矿物质的实验室实验和工业试验,结果表明,添加该种类型矿物质可以改善焦炭的热反应性和反应后强度。     

典型碱金属、碱土金属对不同变质程度煤焦溶损反应的催化作用

试验研究发现,添加碱金属、碱土金属对低变质程度煤焦反应性的催化作用小于焦煤等中等变质程度煤焦反应性。它们对焦炭溶损反应的催化作用顺序为：K〉Na〉Ca〉Mg,且随着添加量的增加,催化作用越强。随反应时间和典型金属添加量的增加,以及温度的升高,焦炭转化率越大。     

炭化和气化过程中煤矿物质的转化

近几年的研究强调了焦炭中的矿物质对焦炭反应性的重要影响。研究表明,焦炭反应性随磁铁矿、磁黄铁矿、有机硫和铁含量的增加而升高,而磷酸铁和硅酸铁对煤气化过程无催化作用。     

焦炭热性质的影响因素分析

结合焦炭在高炉内的降解过程,综述了近年来焦炭热性质影响因素的研究进展,其中包括:原料煤性质、煤中矿物质、高炉内矿物质、焦炭光学组织结构、焦炭气孔结构等,指出焦炭热性质研究的重点是如何降低焦炭反应性和提高焦炭的反应后强度。     

不同类型焦炭光学组织与CO_2反应性关系的研究

以不同配煤方案配合煤所炼焦炭为研究对象,测定了焦炭的光学组织组成、焦炭反应性CRI和反应后强度CSR,利用多元线性回归的方法找出不同光学组织组成与焦炭热性质的关系;同时测定了焦炭与CO_2反应后焦样的光学组织组成,并定量计算了不同类型焦炭光学组织与CO_2反应性的关系。研究结果表明,不同类型焦炭光学组织与CO_2反应性存在较大的差别,即各向同性、丝炭与破片、细粒镶嵌、片状、完全纤维、不完全纤维、中粒镶嵌、粗粒镶嵌与CO_2相对反应性的大小为:9.3、8.5、6.2、5.4、2.6、1.5、1.3、1。     

新疆煤相变机理的研究

利用煤岩学对新疆不同变质程度煤进行了相变机理的研究,探讨了焦炭显微结构对焦炭热性能的影响。当焦炭粗粒、片状组分增加,同性组分减少时,焦炭的应性低,反应后强度提高;当焦炭纤维结构增加,粗粒、片状组分减少时,焦炭的反应性增加,反应后强度下降。     

煤中灰成分对焦炭质量的影响

通过对西北地区煤和内地部分煤种的基本性质、灰成分分析,以及对西北煤配煤后所得的焦炭进行焦炭反应性和光学组织的研究,探讨了灰成分对焦炭性能和微观结构的影响.在分析无机矿物质的催化作用基础上,研究了高碱金属含量煤的炼焦机理及焦炭特殊性的原因.     

细镶嵌状结构焦炭的性质和结构

焦炭的性质主要取决于它的微观结构,就细镶嵌状结构焦炭来说,其热膨胀系数随消光轮廓间距增大而降低,而石墨化度则随消光轮廓间距增大而增大,其最重要的原因是焦炭的结构单元的尺寸随消光轮廓间距增大而增大,扫描电镜的观察结果证实了这一点。文中对两种焦炭的显微结构进行了研究,对热处理的影响作了讨论。     

神华煤的基本特征及配入炼焦对焦炭热性质的影响

低变质程度的神华煤就其本身性质而言不能用于炼焦生产,但是为了扩大其应用范围,同时缓解中国炼焦煤资源紧缺的现状,有必要进一步探讨神华煤的焦化特性。笔者较系统研究了神华煤的基本特征、煤岩特征及不同比例配入炼焦时对焦炭热性质和光学显微组织的影响。     

The strength of industrial cokes. 5. Influence of coke breeze in a coal charge on tensile strength of coke

The purpose of this study was to determine the influence of different proportions and different particle sizes of coke breeze in a coke-oven charge on the tensile strength of the coke. The diametrical-compression test was used to determine the tensile strength of the coke produced in a 10-t test oven and the results obtained were considered in relation to the composition of the oven charge, the coke micum indices and to parameters describing the coke texture. It was established that breeze additions caused measurable but nonsystematic changes in the coke tensile strength and that decreasing the breeze particle size generally increased the coke tensile strength. These changes could not however be directly related to changes observed in the density, porosity, pore-wall thickness or mean pore size of the cokes. The previously established relations between micum indices and the tensile strength of foundry cokes were also found to be inapplicable. The conclusion was drawn that the behaviour described is associated with some, at present unestablished, factor of the blend composition, one possibility being the relative proportions and compatibility of the ‘binder’ and inert material acting through their influence on those aspects of the coke microstructure which control the coke breakage.     

Coke reactivity: Effect of Fe2O3 and K2CO3 addition to the coal charge before carbonization

Six individual coals and one blended metallurgical coal were used in this investigation, and two additives, Fe₂O₃ (up to 1%) and K₂CO₃ (0.5%), were added to each coal before carbonization. Results showed that the additives strongly increase CRI (coke reactivity index) and decrease CSR (coke strength after reaction) of each coke, but there are no significant changes in coke microstructure.     

焦炭气孔率对焦炭热性能的影响

通过研究40kg试验焦炉单种煤焦炭、配合煤焦炭及工业焦炉焦炭的气孔结构及焦炭热性能,得出气孔率对焦炭热性能的影响。焦炭气孔率对焦炭热性能有较大影响,随着气孔率的增加,CRI增加,CSR降低;工业焦炉焦炭气孔率与焦炭热强度之间关系密切,气孔率每增加1％,CRI增加0．48％,CSR降低1．46％。用气孔率预测焦炭热性能,对指导焦炭生产、控制焦炭热性能具有指导意义。     

焦炭反应性及反应后热性质及其检测方法

通过焦炭反应性(CRI)和反应后强度(CSR)在模拟高炉内焦炭热性质中存在问题的分析,提出了CRI和反应后热性质(PRTP)及其检测方法,指标包括溶损反应开始温度、溶损速率、等溶损率后强度、反应后热处理性和热处理后强度. 7种高炉用焦炭的CRI和CSR及CRI-PRTP的实验研究和分析显示,几种焦炭的反应初始温度有较大差别,最大相差44℃. 焦炭D的CSR为74.1,但较高的CSR主要是其低CRI造成的,用等溶损率后强度能够更好地评定焦炭抵抗溶损劣化的能力. 焦炭A的溶损-热处理后与等溶损率后强度相比,降低幅度达到了7.1%. 研究证明,用CRI-PRTP评定焦炭热性质可行.     

炼焦工艺条件对焦炭反应性和反应后强度的影响

通过40 kg焦炉炼焦实验,研究了加热速率、焦饼终温、焖炉时间、入炉煤堆密度及入炉煤细度等对焦炭的CRI(焦炭反应性)、CSR(反应后强度)的影响。结果表明:为保证焦炭成熟和获得较低的CRI值,较高的CSR值,焦饼终温应控制在1000～1050℃范围内。炼焦时焖炉时间应控制在3 h以上。提高入炉煤堆密度,可显著改善焦炭的热性质。入炉煤细度控制在90%左右时,CRI、CSR值较佳。提高加热速率,特别是粘结阶段的升温速率,有利于改善焦炭的热性质。     

Inhibition to coke deterioration by benzene pyrolysis using response surface methodology

To solve the energy-saving and emission-reduction problem which caused by the deterioration of the thermal properties of coke in blast furnace and to improve the technologies applied to the inhibition to coke deterioration, benzene pyrolysis carbons were used to infiltrate into coke to inhibit coke deterioration for improving the thermal properties of coke. Taking aim at the coke reaction index (CRI) and the coke strength after reaction (CSR), the optimum infiltration conditions of benzene pyrolysis were researched by chemical vapor infiltration using response surface methodology. The models of regression of the thermal properties of coke with the experimental factors were established. Results indicated that the data were adequately fitted into quadratic models. The pyrolysis reaction time was found to have very significant linear effect on CRI and CSR. The pyrolysis reaction temperature, pyrolysis reaction time, flow rate of carrier gas and benzene temperature were found to have very significant quadratic effect on CRI and CSR, respectively. The interactions between some factors had significant effects on CRI and CSR. The experimental conditions range and optimum conditions were derived from three-dimensional response surface, contour plots and the model equations. Optimum results showed that the value of CRI decreased by about 11.94 wt % and the value of CSR increased by about 9.20 wt % under the optimum conditions. The SEM photos of cokes revealed that the pores of infiltrated coke were filled with pyrolysis carbon particles, which greatly reduced the reaction contact area for CO2 to erode coke. The changes of pore structure illustrated that the pores volume and the specific surface area of the infiltrated coke smaller than that of original coke. So infiltration of benzene pyrolysis can notably improve the thermal properties of coke.     

Treatment of metallurgical coke with an aqueous solution of sodium tetraborate

The effect of the out-of-furnace treatment of metallurgical coke with aqueous solutions of inorganic substances on changes in the coke reactivity index (CRI) and coke strength after reaction (CSR) was studied. It was found that the treatment of coke with an aqueous solution of sodium tetraborate (Na₂B₄O₇ · 5H₂O) exerted the greatest effect on an improvement in the qualitative characteristics (CRI and CSR). Changes in the values of CRI and CSR of metallurgical coke as functions of the concentration and amount of the solution of sodium tetraborate were studied. It was found that the greatest improvement in the values of CRI and CSR of coke was reached upon treatment with a 7.5% solution of Na₂B₄O₇ using 45 l per ton of coke. In this case, the coke hot strength increased by 18.8 rel %, whereas the reactivity index decreased by 13.2 rel %.