冶金焦气孔率和气孔结构与热性能关系的研究

介绍了焦炭气孔结构和气孔率的测定方法,讨论了攀钢煤化工厂生产的冶金焦炭气孔率及气孔结构与热强度之间的关系,分析了配合煤质量和工艺条件对焦炭气孔结构的影响。研究表明,气孔率和气孔平均直径增大,反应后强度降低;气孔壁平均厚度增大,反应后强度增加。控制焦炭的气孔率及气孔结构,对提高攀钢焦炭热强度具有重要的实际意义。     

焦炭微观气孔结构及分形特征的研究

通过引入分形理论研究焦炭微观气孔结构的内在规律和特征,揭示焦炭的反应性与焦炭气孔分形维数变化幅度的关系。采用压汞法对反应前后焦炭的孔结构进行测定,研究CO2浸蚀引起的焦炭微观气孔结构变化,提供了研究焦炭熔损反应的新方法。     

基于体视学的SAP混凝土气孔结构分析与研究

为了研究混凝土在添加高吸水性树脂后其内部气孔结构的变化规律,以及内部气孔结构的变化对混凝土试样抗压强度的影响,基于定量体视学的电子显微图像分析方法,对添加SAP混凝土的内部气孔结构特征展开了相关试验研究.采用干拌的方法拌和SAP混凝土,对不同配合比和不同SAP掺量的混凝土进行分批试验,测定出各组试样的气孔结构参数和抗压强度等,以深层次的剖析SAP对混凝土强度和内部气孔结构的影响.研究结果表明:混凝土内部气孔的平均孔径与间距系数随着SAP含量和水灰比的增加而增大,而混凝土抗压强度则呈现出相反的变化趋势.在配合比相同的情况下,小粒径SAP颗粒对混凝土气孔率的提高效果更为明显,而大粒径SAP颗粒对混凝土气孔平均孔径的提高效果更为明显;水灰比对气孔平均间距系数影响显著,而SAP粒径对混凝土内部气孔平均间距系数的影响不明显.     

高温捣固焦与顶装焦抗碱性差异研究

通过研究负碱焦炭在短时间内的溶损反应程度,发现捣固焦在反应初期速率较低,但在高温呈现较高的反应性；反应后,顶装焦内部以中粒和粗粒结构为主,气孔较小,数量多,而捣固焦内部以各向异性和细粒结构为主,存在大的贯穿气孔,气孔数量少；捣固焦内存在贯穿气孔和细小裂纹,气孔不均匀度略大于顶装焦.     

单种煤煤岩参数对焦炭质量的影响规律

通过研究各单种煤的镜质组平均最大反射率R0max及分析单种煤40kg小焦炉试验所得焦炭气孔结构,得到焦炭气孔结构参数的回归方程及其影响规律,可用于指导配煤炼焦。     

气孔结构参数对耐火浇注料性能影响的研究进展

气孔的存在是耐火浇注料基质显微结构的重要特征,因此介绍了气孔率、气孔尺寸和孔径分布等气孔结构参数对耐火浇注料强度、热导率、热膨胀系数、抗渣性和抗爆裂性等性能影响的研究进展,指出了在研究过程中存在的问题,并为今后的研究方向提出了一些建议。     

二氧化碳浸蚀后的焦炭微观结构研究

研究了与二氧化碳反应前后的单种煤所炼焦炭和工业用焦炭的气孔结构和光学组织的变化规律,结果表明:经二氧化碳浸蚀后焦炭的气孔率都增加,气孔壁减薄,气孔平均直径增大;不同种类的焦炭,浸蚀的温度和时间不同时,其气孔结构的参数变化程度也有所不同。无论是单种煤所炼焦炭还是工业用焦炭,受二氧化碳浸蚀后,其各向同性、丝炭和破片组织含量减少;而粗粒镶嵌、纤维状和片状组织含量增多;OTI指数增大。     

抛光渣体系发泡陶瓷的发泡性能研究

以工业上成熟的抛光渣体系配方制备发泡陶瓷,探讨了烧结温度对其发泡性能的影响。同时,与外加发泡剂的抛光渣体系发泡陶瓷试样的显微结构、线收缩和体积膨胀率进行了对比分析,探讨了孔结构对发泡陶瓷试样强度和热稳定性的影响。研究发现,抛光渣具备一定的发泡能力,自身可发泡形成尺寸为10~200 μm(1 160~1 220 ℃)的球形气孔结构,孔壁的结构较致密。其对烧结温度十分敏感,在1 180~1 200 ℃范围内,发泡陶瓷试样的体积膨胀了2倍。外加SiC发泡剂能显著提高抛光渣体系发泡陶瓷试样的发泡能力,使其气孔尺寸增加10倍左右,但气孔形状不规则,孔壁结构中存在微小气孔。研究结果表明,外加发泡剂后,抛光渣自身发泡形成的壁孔结构使发泡陶瓷气孔率增加,强度损失较少,导热系数降低,且壁孔结构中的气孔分布不均匀,使发泡陶瓷的热稳定性降低。     

焦炭抗拉强度与气孔结构间关系初探

研究了单独气孔特征参数与抗拉强度之间的关系，结果发现，它们之间除了气孔率外，相关性都比较差；在研究复合气孔结构参数与抗拉强度之间关系时，其结果表明不同类型焦炉得到的焦炭，二者之间均存在良好的相关关系。     

焦炭开闭气孔比率与微细气孔的位置

为研究高温状态下焦炭的粉化行为，作者调查了反应前后焦炭的组织变化情况。为了查明焦炭的气孔结构，又在真空下将添有荧光涂料的树脂渗入焦炭中，并用紫外线照射和观察试样，获得更加清晰的图像，以便有效分析焦炭的气孔结构。     

干馏条件对油页岩半焦孔隙结构的影响

油页岩干馏过程中发生挥发分物质的析出,导致颗粒的孔隙结构发生重大的变化,进而会对油页岩半焦的燃烧反应、成灰等特性产生重要的影响。利用扫描电镜、氮气吸附/脱附法对不同干馏温度、不同干馏时间下制备得到的桦甸油页岩半焦进行了孔隙分析,并与前人针对相同样品的油页岩半焦燃烧特性实验研究进行了对照分析。结果表明,在实验范围内,随干馏温度增加,受热解二次反应产生的焦炭对孔隙堵塞的影响,油页岩半焦孔隙比表面积和比容积先增加后减小;随干馏时间增加,伴随着小孔之间的合并,油页岩半焦孔隙比表面积先增加后减小,比容积单调增加。     

Pore-scale study of reactive transfer process involving coke deposition via lattice Boltzmann method

Coke deposition during catalytic industrial processes can lead to the narrowing and blockage of pore structures inside particles so as to influence the catalyst performance. In this work, a direct pore-scale simulation is carried out by the lattice Boltzmann method to investigate the change of pore structures caused by coke formation. Coke deposition processes in the single pore and complex porous medium are evaluated. The interaction of pore structure and mass transfer under the condition of coke deposition is analyzed. The results reveal that the pore narrowing and blockage can hinder the viscous flow and Knudsen diffusion, resulting in the change of mass transfer mechanism, which is sensitive to gas rarefaction effect and coke deposition rate as well as surface roughness. For the complex porous medium, the uniformity of pore size distribution becomes weak under the gas rarefaction effect and coke deposition.     

活性焦孔结构演变规律及对脱硫性能的影响

采用气体活化法制备活性焦,通过控制温度和烧失率来控制孔结构生成过程,制取具有特定孔结构的活性焦。采用N₂吸附法对样品的孔结构进行表征,并在固定床实验系统上对不同样品的脱硫性能进行测试研究。研究发现:活性焦制备过程中,低温活化有利于活性焦微孔结构的形成和脱硫性能的提高,微孔是活性焦脱硫反应发生的主要场所,中孔和大孔作为分子扩散通道并具有存储H₂SO₄的作用,微孔比表面积可以作为判断活性焦脱硫性能的关键指标。     

Study of coke structure by computerized X-ray tomography: A review

Recent research regarding the use of computerized X-ray tomography to obtain a three-dimensional distribution of the density within coke samples is reviewed. Tomographic data provide a detailed three-dimensional picture of the coke??s pore structure. The changes in coke structure due to its production technology and subsequent treatment may also be established. Together with other physicochemical data, computerized X-ray tomography provides a more complete characterization of blast-furnace coke.     

Effect of steam injection on pore structure and distribution in coke samples produced by delayed coking

Porous structure of the petroleum coke produced in delayed coking technique is investigated by high-resolution X-ray computed tomography imaging. Cokes analyzed for these studies were produced from decant oil with and without steam injection. Images taken at different regions along the length of the coke columns have been used to characterize and quantify porosity and pore size (>20 μm)/shape distribution within the coke samples. Fractal analysis was performed to investigate the pore complexity distribution within the coke and to compare the two coke samples produced by different methods. High-resolution X-ray computed tomography was utilized also to scan a 1.1 cm section in the middle of the steam treated coke in volume mode to scan 80 images in one scan. Multi-planar reconstruction and 3D rendering of the pores were used to understand how the flow channels are developed and the degree of connectivity.Results showed that each coke sample shows a wide range of pore sizes and shapes that vary along the length of the coke samples. This variation in the coke that is not subjected to steam is more pronounced. Quantification of macropore size distribution shows that, in each coke sample the middle sections are the most similar regions in terms of pore size distribution and porosity. In general, steam injected coke has larger pores. Box counting fractal analysis in the cokes shows that pore distribution has fractal scaling at the locations scanned and helps in the interpretation of the pores at different locations in terms of their complexity in the distribution and shapes.     

干熄焦工艺对捣固焦与顶装焦质量的影响

通过检测焦炭的M40、M10、CRI、CSR、焦炭的气孔结构、光学组织结构，分析了干熄焦工艺对顶装焦和捣固焦质量的影响程度，检测表明，捣固焦炉配干熄焦工艺技术不但可提高焦炭质量，还可提高弱黏煤比例，节约优质焦煤。