基氏流动度在配煤炼焦中的应用

针对迁安中化炼焦煤采用常规煤质指标分析出现的单种煤常规指标较好,配煤炼焦后焦炭强度下降的问题,采用基氏流动度分析了常用两种中强黏结性炼焦煤A煤和B煤的煤质,探讨了其与常规煤质指标的关系,介绍了基氏流动度在配煤炼焦中的应用情况及存在问题。结果发现,A煤和B煤的常规煤质指标接近,最大基氏流动度分别为7209 ddpm和829 ddpm,可以较好区分两种煤;基氏流动度特征指标中的软化温度、塑性温度区间及最大流动度可反映炼焦煤的基本性质;炼焦煤的最大流动度的对数值在2.2~3.0、挥发分在23%~27%时,焦炭M40>87%、M10<7%。     

吉氏流动度在煤炭焦化领域的应用

为了促进吉氏流动度指标在煤炭焦化领域的有效应用,介绍了当前国内外用于表征炼焦煤黏结性能的吉氏流动度指标测试方法、标准及主要设备应用情况;探讨了吉氏流动度指标在异常炼焦煤判别、对同类别炼焦煤黏结性精准识别、判别易氧化煤黏结性变化、对焦炭质量准确把握等煤炭焦化领域的应用;概述了最大流动度与镜质组平均最大反射率组合形成用于气化焦生产的α_(max)-R配煤方法。提出了煤炭焦化领域应充分认识吉氏流动度指标对炼焦煤黏结特性表征的独特优势并科学运用该指标指导炼焦煤的合理应用,指出我国应重视适合国内煤质特性及测定标准的吉氏流动度测定仪的研发与应用。     

炼焦煤奥亚膨胀度指标特征分析

通过对炼焦煤奥亚膨胀度指标、黏结性指标、胶质层最大厚度Y值和挥发分等质量指标的研究,分析了不同煤种奥亚膨胀度指标与以上质量指标之间的关系,结果显示奥亚膨胀度与炼焦煤的变质程度有良好的相关性,对配煤炼焦具有指导意义。     

几种煤的基氏流动度浅析

通过测定几种常用炼焦煤的基氏流动度,分析了不同煤种的基氏流动度曲线差异与特性指标不同的原因.结合粘结指数G值,对应用基氏流动度作为配煤指标的可能性进行了探讨,并指出了基氏流动度在炼焦配煤中的作用.     

炼焦煤基氏流动度指标在韶钢的应用

主要介绍基氏流动度指标在韶钢的应用,通过小焦炉炼焦试验及实际生产应用的对比分析,指出炼焦煤基氏流动度指标能反映一般常规指标难以表征的煤质特点,但需结合图谱以及煤岩分析与焦炭显微结构分析才能全面指导炼焦配煤生产.     

配合煤塑性体流动性与其黏结指数的关联性研究

对炼焦煤黏结指数(G)和基氏流动度等指标进行分析测定,研究配合煤G值和基氏流动度特征指标的变化规律.结果 表明,相同煤种间配合煤的G值和最大流动度具有良好的加和性,不同煤种间加和性差;增加低流动度煤种的配入比例,会导致配合煤软化温度升高,软固区间变窄;配合煤样的G值与lgMF呈线性关系和二次曲线关系的加成.     

微波干燥对炼焦煤煤质影响的实验研究

通过选取不同炼焦煤的特征指标,对微波干燥前后这些特征指标的分析比较,探索微波干燥技术对炼焦煤煤质的影响.结果表明,微波干燥技术在去除炼焦煤水分的同时,对炼焦煤的工业分析和黏结指数无明显影响;对基氏流动度和奥亚膨胀度存在正影响,但不明显;对胶质体影响较大,特别是其过程行为.因此微波干燥技术对炼焦煤煤质无较大影响,如果存在影响,也是有利于改善炼焦煤煤质的.     

炼焦煤焦化特性评价指标探讨

介绍了奥亚膨胀度、基氏流动度、罗加指数、胶质层指数、黏结指数和镜质组平均最大反射率等冶金煤焦化特性评价指标的建立和测试方法,以及各评价指标在我国的应用情况。同时讨论了各个指标对胶质体的原生黏结性、膨胀程度引起的黏着性和焦炭残留物强度这3个焦化特性的表征。     

基氏流动度指标分析及应用研究

分析了基氏流动度指标在指导配煤炼焦中的作用,炼焦试验结果表明,基氏流动度指标能够快速准确地鉴别煤种,最大流动度与黏结指数、胶质层指数、镜质组最大反射率有明显的相关性,配煤时应充分考虑流动度和温度指标。     

煤热解过程中胶质体流动指数F的研究

以煤的基氏流动度实验作为研究胶质体性质的出发点,提出以加权平均流动度lgF_(wa)和最大流动度lgF_m分别代表整个阶段胶质体所体现的平均质量和最佳质量,并提出以软固温度区间T_r-T_s表征胶质体数量.在此基础上,以因子分析为综合评价胶质体性质的模型,建立一个全面表征胶质体性质的新指标——流动指数F,发现流动指数F较lgF_m与煤工艺性质有更密切的联系,具有更好的加和性,预测焦炭质量更准确,表明流动指数F作为黏结性指标可以全面反映胶质体的性质.     

Oxidation studies on coking coal related to weathering. 3. The influence of acidic hydroxyl groups,created during oxidation,on the plasticity and dilatation of the weathered coking coal

A high-volatile bituminous coal possessing a high Gieseler fluidity and large dilatation was subjected to slight oxidation in air under chosen conditions. The resultant ‘oxycoal’ was treated with various chemical reagents in order to determine to what extent the original caking properties of this coal, as measured by Gieseler fluidity and dilatation, could be restored. Treatment with aqueous barium hydroxide or barium acetate solutions succeeded in doing so to a considerable degree. It is tentatively concluded that certain acidic hydroxyl groups formed in the course of oxidation are indirectly responsible for the deterioration of fluidity and dilatation — possibly via condensation reactions involving the hydroxyl groups — during subsequent pyrolysis of oxycoal. The presence of carboxyl groups appears to have no effect.     

煤的基氏流动度测定标准及测定仪研究

对各国和地区采用基氏塑性仪测定煤的流动度的相关标准进行了研究,美国、日本等国和地区的研究较为完善。比较分析了各国煤的基氏流动度测定标准的不同之处,除部件精确度要求有差别外,最主要的不同之处为煤甑坩埚底部中心凹槽坡口角度不同,这就产生了搅拌桨与坩埚底部的不同接触方式。总结了中国煤的基氏流动度测定标准以及基氏流动度测定仪研制过程中存在的主要问题及应用、发展现状。研究表明,基氏流动度的测定尚未有相关的国家标准,而国内测定仪多为国外进口,国内研制的设备精度不高,检测效率较低;在煤的流动度指标应用上,日本等国将其用于指导配煤炼焦、预测焦炭质量,而中国也在这些方面逐渐进行研究。     

Studies on artificial coal. 3. Polycondensates from aromatic hydrocarbons

Artificial coals (AC) or coal-like model substances were prepared by the polycondensation of polynuclear hydrocarbons. Anthracene and pyrene gave caking models while phenanthrene (under severe conditions) produced a non-caking model substance. These polycondensates were subjected to solvolysis, thermosolvolysis, thermogravimetry, Gieseler plastometry and differential thermal analysis. The principal conclusions drawn are:

1. (1) The role of the starting aromatic hydrocarbon in deciding the nature of the polycondensate was important for a given set of conditions of polycondensation.

2. (2) The three models behaved differently in yields of chloroform extract by soxhlet extraction: 35.7% (anthracene) and only 0.9% (pyrene), and 3% (non-caking, phenanthrene). Also, in solvolysis and thermosolvolysis the anthracene model behaved like the caking AC and the phenanthrene model behaved like the non-caking AC prepared by hydrothermal carbonification. The preheating of all these models except that from pyrene caused a progressive fall in the subsequent yield of chloroform extract, unlike the other models or AC but like natural caking coal.

3. (3) The anthracene and pyrene models had strikingly high maximum fluidity (>27 000 dial div./min), thus resembling the highly fluid sawdust AC. They also showed low softening temperatures. The stability of chloroform extract as shown by the thermosolvolysis studies was found to be of greater significance than the maximum fluidity or the characteristic Gieseler temperatures in correlating with the caking properties of coal models.

4. (4) Thermograms of these models displayed predominantly exothermic behaviour during pyrolysis, as with other AC and natural coals.

     

Studies on artificial coal. 2. Thermogravimetry, plastometry and differential thermal analysis

The artificial coals (AC) or coal models were prepared from sawdust, lignite and cork by the method of hydrothermal carbonification. The specific techniques used to study their pyrolytic behaviour were thermogravimetry, Gieseler plastometry and differential thermal analysis (DTA). The principal conclusions drawn are:

1. (1) The initial stage of pyrolysis of AC can be considered to be governed by an overall reaction of first order, as in the case of natural coals.

2. (2) All caking types of AC showed quite low softening points (75–210 °C), the values for sawdust AC being lower than those for the cork AC. The latter showed fairly sharp peak values of the temperature of maximum fluidity, but the sawdust AC showed only a range of temperatures of maximum fluidity, the upper limit being less than the maximum fluidity temperature of the cork AC. However the temperatures of resolidification were consistently high, namely 425 °C and above, thus bringing in a significant point of similarity with natural caking coals.

3. (3) The value of maximum fluidity was very high for one AC sample, exceeding 27000 dial div./min. Such a high value is rare for natural caking coals. With the latter, no correlation could be observed between the caking properties and maximum fluidity. Hence the role played by the stability of the plastic mass may be the more dominant factor in the caking process.

4. (4) From the comparison of the softening temperatures and the temperatures of active decomposition of the AC, it is inferred that the process of initial softening of coal may be physical in nature.

5. (5) The AC indicated an overwhelming exothermicity in their primary pyrolysis, thus behaving like the natural coals studied under similar experimental conditions.

     

Effect of alkali treatment on the caking properties of coal

Three weakly caking and non-caking high volatile bituminous coals from India were converted into good caking derivatives by treatment with alcoholic alkali at 250–300 °C and 22–25.5 MPa. These derivatives showed high Gieseler fluidities with wide plastic range and may be useful as additives to coals for oven charges. During alcoholic alkali treatment, the organic material of coal undergoes extensive degradation into relatively low molecular weight substances which possess sufficient thermal stability to maintain a fluid state on carbonization. Increasing the severity of alkali treatment produces a pitch-like material from coal, with a potential use as a binder for formed coke, carbon electrodes etc.     

Some aspects of the role of coal thermoplasticity and coke structure in coal gasification: 3. The effect of rank,pitch and sodium carbonate on Brabender plastometry parameters

The thermoplastic properties of coal are a significant factor in determining gasification behaviour in most gasification processes. This investigation has involved the use of constant shear rate (Brabender) plastometry to study the plastic properties of a wide range of coals varying from 101 to 902 in the NCB Classification. The results obtained show more complex behaviour during the carbonization process than reported previously and are compared with ASTM Gieseler plastometry and BS dilatometry results. Some coals have two peaks in the caking region of the plastometry curve. This has been attributed to an initial peak corresponding to softening of the coal followed by caking due to active decomposition. The phenomenon was observed for coals with ranks 301a to 602, the temperature difference between the peaks being largest for the prime coking coals. It has been shown that this technique produces much additional information about the initial phase of the carbonization process. The effect of pitch and sodium carbonate addition on the plastometry parameters has also been studied. The results show that small amounts of these additives can radically change the plastometry curves. Pitch increases the plastic range whereas sodium carbonate reduces it. The addition of sodium carbonate tends to modify the plastometry curves so that they are similar to coals of lower rank whereas pitch addition, in general, tends to increase fluidity and, in the case of low-rank coals, produces plastometry curves similar but not identical to higher-rank coals.     

烟煤粘结指数准确测定的影响因素分析

粘结指数的测定在煤质分析中是很重要的,它是判别煤的粘结性、结焦性的关键性指标。测定烟煤的粘结指数后,就能确定它的工艺类别,根据煤样粘结指数的高低,可以大致确定该煤的主要用途。     

Further studies of coal oxidation

The low-temperature oxidation of coal has been investigated by Fourier transform infrared spectroscopy (FT-i.r.). Samples were oxidized at 140 and 60 °C for intervals of a few hours to days. These FT-i.r. results were correlated to changes in the thermoplastic properties of the coal measured by a Gieseler plastometer. The loss of Gieseler fluidity as a function of oxidation time corresponds to loss of aliphatic CH groups. Curve-resolving methods were used to distinguish between various C = 0 functional groups. At both oxidation temperatures there was an overall increase in carbonyl and carboxyl groups, but in different relative proportions depending on the oxidation temperatures.