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。     

试论焦炭的显微特征对其机械强度的影响

文中采用数理统计的方法，全面系统地探讨了焦炭的显微特征与焦炭机械强度之间的关系。结果表明，单种煤焦炭的机械强度是由其光性结构和气孔构造两方面决定的，而配煤焦炭析机械强度则是由其气孔构造特征，尤其是孔壁厚度，其次是孔径决定的。     

炼焦煤热解过程交互行为与气孔特征的关系

选取了气煤、肥煤、焦煤3种不同变质程度的单种炼焦煤,在终温950℃下干馏成焦。通过显微图像分析法测量得到了焦炭的气孔结构参数,通过热重分析测量得到了炼焦煤热解挥发分产生过程,通过基氏塑性仪测量得到了炼焦煤的热解软化流动过程。结果发现,炼焦煤挥发分的产生与软化流动行为的相互作用决定了焦炭气孔结构的差异。     

确定炼焦煤硫转化率方法的研究

根据焦炭中硫为各单种煤中所含硫转化为焦炭中总硫的原理,通过给定的单种煤的硫含量和配煤方案以及焦炭干基全硫的测定值,计算出单种煤的硫转化率,进而用来预测生产焦炭的硫含量。     

利用40kg焦炉试验预测焦炭硫分及产率

选取炼焦生产用煤进行40kg焦炉试验,研究煤与焦炭间硫的转化和焦炭产率,以预测焦炭硫分和产率。研究结果表明,对于单种煤炼焦,硫的转化率和焦炭产率可近似成一个定值;对于配合煤炼焦,焦炭硫分与焦炭产率可近似成各单种煤焦炭硫分与焦炭产率的加和。在此基础上建立了单种煤和配合煤焦炭硫分及干基焦炭产率的预测模型。     

焦炭抗拉强度的研究

研究了单种煤焦炭抗拉强度与煤的 Rmax、Vdaf、G之间的关系 ,发现它们之间均呈现很好的曲线关系(中等变质程度的煤所得的焦炭抗拉强度高 ) ;且单种煤焦炭的抗拉强度与焦炭的结构强度 ,显微强度测定值之间存在有较好的相关关系 ;还研究了抗拉强度与气化量之间的关系 ,结果表明也存在良好的线性关系。     

焦碳抗拉强度的研究

研究了单种煤焦炭抗拉强度与煤的Rmax,Vdaf,G之间的关系，发现它们之间均呈现很好的曲线关系（中等变质程度的煤所得的焦炭抗拉强度高）；且单种煤焦炭的抗拉强度与焦炭的结构强度，显微强度测定值之间存在有较好的相关关系，还研究抗拉强度与气化量之间的关系，结果表明也存在良好的线性关系。     

坩埚焦性质的研究

研究了单种煤、工业配煤坩埚焦炭与20kg试验炉焦炭的反应性、反应后强度、结构强度、显微强度及配合煤焦炭的光学组织指数间的关系,结果表明,它们之间有良好的相关关系。     

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。     

基于小焦炉试验的焦炭硫含量预测

以40 kg试验焦炉为工具,测定了单种煤及配合煤的硫含量、成焦率、硫残余率等指标,以此为基础建立了焦炭硫含量的预测方程.结果表明,通过积累单种煤数据预测配合煤所生产焦炭的硫含量是可行的,在焦炭硫含量不超过1％时,绝对误差平均在0.03％～0.05％.     

气孔结构对焦炭深层反应影响的初探

研究了气孔结构对焦炭深层反应的影响，并将分开可理论引入到气孔结构的研究中。     

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。     

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。     

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.     

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.     

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。     

A comparative study of the roles of KCN and NaCN as catalytic precursors in the Boudouard reaction

The rate of reaction between carbon dioxide and coke with or without added KCN and NaCN was studied using thermogravimetry. The chemical stability of KCN or NaCN during catalysis, the changes in the concentration of potassium or sodium in coke and the pore structure of coke were studied as a function of time. The influences of these variables on the rate of coke-CO₂ reaction were determined. Since the catalysis depends on the catalyst-carbon contact, the distribution of potassium in the coke structure was examined. A porous solid reaction model was used to examine the contributions of chemical reaction and pore diffusion in the overall rate of coke-CO₂ reaction.