Catalytic graphitization of cokes by indigeneous mineral matter

Indigeneous mineral matter in coals acts catalytically towards graphitization during heat treatment of coals to 2273 K. Nineteen coals of a wide range of rank were demineralized by acid extraction. Original and demineralized coals were carbonized in the range 1073–2273 K, and the resulting cokes examined by optical microscopy, X-ray diffraction and phase-contrast high resolution electron microscopy. Optical microscopy indicated the extent of formation of anisotropic carbon in the resultant cokes. The (002) X-ray diffraction profiles indicated three types of catalytic effect, for which electron microscopy demonstrated different crystallite structures and interrelations. The importance of catalytic graphitization in metallurgical cokes in relation to their strength and reactivity is discussed.     

Effects of catalytic graphitization on Vickers microhardness of a phenolic resin carbon and cokes

The effects of catalytic graphitization on Vickers microhardness have been investigated using a typical non-graphitizing phenolic resin carbon and two coking coals. The hardness of the phenolic resin carbon is reduced considerably by the formation of a turbostratic carbon because of catalytic graphitization. However, the hardness of the coking coals was not lowered by catalytic graphitization. The causes of these phenomena are discussed.     

An evaluation of methods for enhancing the CO2-reactivity of a caking bituminous coal

An evaluation of a variety of reactivity enhancement procedures has been carried out for one bituminous coal (Pittsburgh No. 8). The relative merits of each type of method have been assessed and the extent to which coal char reactivity could realistically be enhanced for gasification by carbon dioxide has been established. Investigations have revealed two main classes of pretreatment type. The first group, consisting of non-catalytic pretreatments such as preoxidation, solvent extraction and co-carbonization with inert materials produced only a moderate increase in char reactivity relative to the untreated parent coke. In contrast, however, the second group, consisting of catalyst pretreated chars, resulted in a large increase in char reactivity compared with that of the parent coke. Group one pretreatments also generally produced non-caking chars with increased microporosity and isotropic carbon texture compared with the largely macroporous anisotropic parent coke. The microporosity was believed to be responsible for the significant pore diffusion/development effects found with these chars during the course of gasification. The most reactive chars were produced by (i) co-carbonization with 15wt% K₂CO₃, and (ii) preoxidation plus 2wt% potassium by ion-exchange. The latter char is preferred on the basis of its more efficient use of catalyst and completely non-caking characteristics.     

煤炭气化焦化废水的微生物处理技术现状

重点介绍了微生物处理技术在煤气化及焦化废水处理中的应用,简单介绍了煤炭地下气化可能造成地下水污染中有机物组分以及所造成有机污染的微生物处理方法。     

热解条件对煤焦气化活性影响的研究进展

简述了原煤性质与温度、压力和热解气氛等热解条件对煤焦结构和气化反应活性的影响;参考该领域的国内外研究成果,分析了热解条件影响煤焦气化反应活性的机理.由于实验设备和研究方法的差异,对温度和压力等热解条件对煤焦气化反应活性影响的评价不尽相同,但总体来讲,热解终温越高、停留时间越长、升温速率越快、热解压力越大,煤焦的气化反应活性越低;热解过程中,原煤性质的差异也会影响煤焦的结构和气化反应活性.煤焦的石墨化应该是导致煤焦气化反应活性下降的主要原因,因此,热解条件的改变,特别是温度和压力的改变对煤焦石墨化进程的影响值得进一步研究.     

Structure of the cokes obtained from the group components separated from coking coal vitrites by selective thermosolvolysis

The examination of the structure of cokes obtained from extracts separated from preheated vitrites of coking coals by progressive and continuous extraction with chloroform was carried out. The structural ordering (interplanar spacing and crystallite dimensions) of the cokes depends on the rank of the parent vitrites but it does not depend on the degree of extraction. The occurrence of optical anisotropy in cokes from the extracts is connected with both the rank of the parent vitrite and the degree of extraction. In the formation of the optical anisotropic structure during the carbonization of coking coal vitrites, the part of the extract which is of small size, which partially undergoes decomposition, is an important factor.     

煤的结构对直接液化反应性影响的分析

系统地分析了煤的组成结构及液化前的预处理对直接液化反应性的影响,包括煤阶、岩相组成、各种矿物质及酸洗脱除、水分及烘干、孔隙性、物理结构及预溶胀、H／C比等,指出不同的工艺条件下它们对直接液化的影响是不同的。     

煤焦二氧化碳气化反应活性影响因素研究现状

煤二氧化碳气化反应是一种煤清洁利用的手段,其关键是提高反应活性。综述了原煤性质、热解过程、反应温度与压力、催化剂,以及二氧化碳气速、煤焦的粒度等因素对反应活性的影响,并对煤焦气化技术进行了展望。     

炼焦煤中灰分对焦炭热性能的影响

研究了炼焦煤的灰分和催化指数,通过小焦炉实验进行了焦炭的反应性和反应后强度的测定。结果表明,灰分催化指数对焦炭的反应性和反应后强度的影响显著。焦炭的反应性与灰分碱性催化指数呈正线性相关,焦炭的反应后强度与灰分碱性催化指数呈负线性相关。     

Aspects of gasification and structure in cokes from coals

Cokes were prepared from nine coals of different rank and characterized by surface area measurement, reactivity to carbon dioxide at 1473K and Raman-laser spectroscopy. Rates of gasification of cokes on a unit surlface area basis (K¹ = g m^?2 min^?1) decreased with increasing rank of parent coal based on maximum oil reflectances. However rates of gasification could not be related to coke structure as measured by Raman-laser spectroscopy.     

蒙古焦煤的煤质研究

对蒙古焦煤进行了工业分析、煤岩分析、流变性和膨胀性分析、以及焦炭显微结构分析,结果表明,蒙古焦煤变质程度略偏低,介于1/3焦煤和焦煤之间,G值、Y值高,膨胀度高,流动性低,单种煤结焦性能好,但煤岩组成不稳定.不同批次的蒙古焦煤煤质波动较大,与我国优质焦煤相比存在较大差异,配煤时应根据具体情况优化使用.     

煤焦加压气化反应性研究

利用加压热分析仪,测定了义马煤焦的CO2气化反应性。结果表明:随温度的提高,义马煤焦的反应性和反应速度呈增加趋势,与前期研究常压下的情况一致;压力对气化反应的促进作用不明显,且温度对气化过程的影响大于压力;反应速率在初始阶段最大,随后逐渐减小。经过动力学计算表明:反应速率与温度的关系符合Arrhen ius定律;反应级数随温度增加而减小,近似于线性关系;煤焦活化能大约为60.02 kJ/mol。     

活性炭催化臭氧化处理煤化工生化出水的试验研究

本文以哈尔滨煤化工有限公司污水处理厂的二级出水为研究对象,以粒状活性炭、壳状活性炭为主要实验材料,测定其对煤化工生化出水的处理效果。以活性炭和O3分别单独处理煤化工生化出水,以及应用O3-活性炭体系处理煤化工生化出水两部分进行试验研究。在分析各处理效果的同时,着重研究活性炭催化O3对煤化工生化出水的有机物降解效果。     

Some physical properties of Canadian coals and their effects on coal reactivity

The pore volume, surface area and compressibility of eleven Canadian coals, varying in rank from lignite to semianthracite, have been determined by mercury porosimetry, gas adsorption method and relations derived from helium and mercury densities. The total pore volume was measured in the diameter range of 0.2 nm–2.98 μm, which was subdivided into two groups, namely the micropore region (< 0.0036 μm) and the combined meso- and macropore region (0.0036–2.98 μm). It has been determined that the porosity of the eleven coals studied varies from 2 to 39%. It has been found that the total pore volume, micropore volume, surface area and the apparent compressibility of these coals decrease with increase in the carbon content, or the rank of the coals. The effect of the total pore volume, micropore volume and surface area on chemical reactivity of the coal is discussed separately. A good correlation was obtained between the carbon content and helium density of the coal after correction is made for the mineral content.     

煤灰对气化反应性的影响

讨论了煤灰在气化过程中对气化反应性的影响,主要为:在低温下,某些矿物组分对气化过程有催化作用,但在高温下,矿物发生变化,会生成无催化活性的组分;当气化温度接近或超过煤灰熔融性温度时,煤灰发生熔融甚至团聚,导致反应比表面积降低,催化矿物分散性变差,影响气化反应性。     

射流流化床体积效应对煤气化特性的影响

根据射流流化床内流体流动特性,在流体动力学行为相似的基础上,利用化学动力学软件Chemkin构建了射流床煤气化炉的动力学模型,通过体积放大引起物料停留时间及流体力学相似性的改变,研究其对射流床中物料特性的影响.分析了射流流化床几何相似放大与高径比减小放大对反应器特性的影响,认为等高径比放大停留时间较长,反应器内流体力学相似性较好,在后续工艺对出口组成要求较高时,采用此放大原则能满足要求.     

基于煤显微结构的炼焦用煤评价及应用

为提出适合鞍钢鲅鱼圈分公司的炼焦用煤结构,利用全自动智能型煤岩分析系统分析了鞍钢鲅鱼圈所用不同牌号各炼焦煤的煤岩特征,结合传统炼焦煤煤质指标,对各炼焦煤的煤质特征进行评价,并将煤岩学应用于炼焦配煤煤种调整、配比调整中。结果表明,根据煤岩分类标准,鞍钢鲅鱼圈所用焦煤中含焦煤成分60.2%,肥煤成分31.6%;鲅鱼圈所用炼焦煤中,进口煤煤质较为单一、煤质较好,其中60%以上为单一煤层煤,而国内煤的混煤现象较为严重,单一煤层煤不足20%。煤岩学理论应用于鞍钢鲅鱼圈炼焦生产后,在炼焦煤评价中增加了煤岩学指标,扩大了精煤来源,提高了焦炭质量,焦炭抗碎强度M_(40)从2011年的88.11%提高到2013年的88.87%,焦炭耐磨强度M_(10)从2011年的6.75%降低到2013年的6.38%。     

Studies related to the structure and reactivity of coals : 18. The chemical structures of products from reactions of a suite of higher rank Australian coals

The structure of the oils, asphaltenes and residues obtained by the thermal reactions of a suite of Australian higher rank coals under hydrogen or nitrogen have been studied by chemical and spectroscopic methods. The host-guest model that has been used to describe the structure of Australian brown coals cannot be applied directly to the higher rank coals. Evidence is provided that suggests that a modified version of the model may be of use in describing the structure of some subbituminous coals. The methodology has proved to be useful in the understanding of structural features of coals which are often not rank dependent, e.g. Callide coal (ABL2), a subbituminous coal, has been shown to have characteristics of both very high and also low rank coals.     

煤催化气化过程中钾催化剂回收的实验研究

对内蒙平庄煤-蒸汽催化气化过程残渣中KOH催化剂的回收进行了实验研究,考察了时间、温度、水渣比和洗涤次数等条件对钾催化剂回收率的影响。实验结果表明,水蒸气催化气化过程中,催化剂的流失可忽略不计。水洗法回收可溶钾占总钾量的80%,回收所得催化剂的有效成分为K2CO3和KOH,占总回收钾量的90%以上。钾收率随时间的增长而快速提高,一般洗涤4 h即可达到预期的收率;升高温度和增大水渣比能明显提高催化剂的收率;水洗洗涤3次,能回收90%左右的可溶钾。     

Influence of coal characteristics on CO2 gasification

The rate of CO₂ gasification of a coke is one of the most important qualities of metallurgical coke. Many workers are trying to estimate the rate of CO₂ gasification of coke by studying properties of coal, such as the reflectance of vitrinite and the amounts of inertinite and ash in coal. The specific-gravity separation method is used to prepare coals which possess almost the same reflectance, but contain different amounts of inertinite and ash. The relation between the rate of gasification and the properties of coal is quantitatively explained.