Direct determination of the clinkering properties of rammed coal and batch

A direct method is proposed for determining the clinkering properties of rammed coal and batch used for industrial coking. This method permits evaluation and selection of individual clinkering coals and satisfactory prediction of the coke quality obtained with preliminary ramming of the coal batch.     

Effect of petrographic property of single coking coal on caking and coking properties

对不同变质程度单种煤的煤岩性质以及对应的40kg试验焦炉所炼焦炭的性质进行测定和分析表明,单种煤的黏结性不仅受煤变质程度影响,而且受炼焦煤中煤岩组成的影响,单种煤的镜质组平均最大反射率在1.1％左右时,煤的黏结性最好;镜质组反射率分布在1.1％～1.3％所占比例为30％左右时,所得焦炭的M40和M10最好.     

单一炼焦煤煤岩性质对黏结性和结焦性的影响

对不同变质程度单种煤的煤岩性质以及对应的40kg试验焦炉所炼焦炭的性质进行测定和分析表明,单种煤的黏结性不仅受煤变质程度影响,而且受炼焦煤中煤岩组成的影响,单种煤的镜质组平均最大反射率在1.1%左右时,煤的黏结性最好;镜质组反射率分布在1.1%~1.3%所占比例为30%左右时,所得焦炭的M40和M10最好。     

Developing new methods of determining the clinkering properties of rammed coal

Theoretical principles are outlined for the development of direct methods of determining the clinkering properties of rammed coal and coal batch. The strength variation of semicoke samples obtained on clinkering various coals with inert filler is considered.     

Determining the coking properties and technological value of coal and coal mixtures

A method is developed for determining the coking properties and technological value of coal from newly identified beds or new sections of existing mines. The coking properties are assessed on the basis of predictions of the strength and reactivity of coke obtained from batch containing coal from single beds and coal blends. The prediction of coke quality is based on the chemical and petrographic characteristics of the coal.     

Statistical analyses and prediction of coking properties of coal

Using regression analyses between the properties of coals and the strengths of their cokes several significant correlations are derived, which are useful to evaluate coals in the making of metallurgical coke. Slight but significant modification was necessary for their application to coal blends. For example, plasticities of the coal blends required a different equation from that derived for the single coals. The region of high coke-strength in the diagram of volatile matter vs. total dilatation was expanded considerably towards coals of lower caking properties by blending of coals, suggesting that the blending may serve to increase the coking properties of component coals. The coke strength, especially after the gasification was found to increase with the increasing inert maceral content in the parent coals up to 30 wt %. The high level of strength was maintained even above 35 wt % of inert content.     

Technological value of coal. 1. Clinkering coal

The concept of technological value is discussed. On that basis, a method of assessing the technological value of coal is recommended. The technological value of the basic clinkering coal in coking batch (Zh, GZh coal) is assessed. Similar estimates are presented for poorly coking GZhO and Zh coal, with somewhat inferior clinkering properties. Three levels of technological value are identified for clinkering coal: the first level includes Zh and GZh coal from enterprises in the Kuznets and Pechorsk basins; the second includes GZhO coal from the Raspadskaya and Vorgashorskaya mines; and the third includes G coal from the Kirov mine. GZhO and G coal from other enterprises in the Kuznets Basin does not function as clinkering coal.     

Assessing the value of coking coal in terms of coking properties and genetic compatibility

On the basis of new research by the Sapozhnikov method (State Standard GOST 1186), as well as data on the yield of volatiles (State Standard GOST 6382) and the petrological characteristics, new definitions are proposed in assessing the clinkering and coking of coal for bed coking. Under that proposal, clinkering properties and coking properties would refer exclusively to samples of individual coals; clinkering ability and coking ability would apply to coal blends and coal batch. As is shown, data for the petrographic composition and vitrinite reflection coefficient permit assessment of the genetic compatibility of coal, which may be used as a behavioral characteristic of coal in batch for blast-furnace coke production.     

泰克煤炭公司炼焦煤煤质及炼焦性能的研究

对加拿大泰克煤炭公司5个单种煤样进行煤质分析,并分别用40kg、200kg和400kg试验焦炉进行炼焦试验。5个单种煤的灰、硫较低,黏结性较好,除TCA煤是简单混煤外,其余均为单一煤层煤,属于较好的炼焦煤类。5个试验煤样随着煤变质程度由高到低所得试验焦炭冷强度和热性质也由高到低;200kg和400kg试验焦炉所得焦炭的冷热态强度综合排列趋势基本一致,并与加拿大第三方实验室炼焦数据趋势基本一致,而40kg试验焦炉所得焦炭的排列趋势却与之差异明显。     

煤种性质对煤粉工业锅炉结焦的影响

燃煤锅炉内结焦会对锅炉运行的安全性和经济性造成极大损害,因而分析影响燃煤锅炉结焦的因素,进而有效预防燃煤锅炉结焦至关重要。在实际应用中,针对影响燃煤锅炉结焦的不同因素,可采取不同的预防措施。研究发现煤的灰熔融性温度、煤粉颗粒大小、锅炉燃烧气氛、一二次风动力场、锅炉截面热负荷和锅炉热负荷等都会影响燃煤锅炉结焦。为了解决某地区煤粉工业锅炉预燃室、炉膛、对流受热面大面积燃烧结焦问题,笔者结合燃煤锅炉燃烧结焦的机理,先后采取调整燃烧气氛、增大二次风刚性、减小煤粉颗粒粒径、更换孙家岔煤粉等措施对不同条件下的结焦现象进行对比分析,发现煤种、煤粉粒径大小是影响某地区煤粉工业锅炉燃烧结焦的因素。通过SEM-EDS(扫描电镜和能谱分析)对锅炉焦块进行微观形貌与元素组成分析,现场取样锅炉现用煤粉和孙家岔煤粉进行煤质及灰成分对比分析,并根据灰成分进行结渣性判别指标计算,结果表明锅炉燃烧现用煤种灰熔融性温度较低,煤灰软化温度Ts为1 170℃,小于1 200℃,为易熔煤,容易结渣,属于典型的易结焦煤种;结渣性判别指标计算结果显示,4项指标评价为"严重",1项指标评价为"中等",结渣性严重。综合分析认为:锅炉燃烧煤种发生改变,煤的灰熔融温度较低是影响某地区煤粉工业锅炉燃烧结焦的最本质因素。为进一步解决现场实际问题,采取破坏煤灰中酸碱平衡,提升煤的灰熔融温度,配合调节煤粉粒径等措施,如对锅炉现用煤种掺混5%的石英,提高煤灰中Si O2含量,掺混后煤粉的灰熔融温度达到1 280℃,提高了110℃;调大煤粉磨机频率,从19 Hz增大到22 Hz,煤粉粒度(200目,0.075 mm)过筛率从70%增大到85%。经过上述调整后,锅炉运行平稳,结焦状况显著改善,燃烧调整措施取得了较好的效果。     

汾西矿业焦煤、肥煤的焦化特性指标分析

对汾西矿业不同煤化程度焦煤、肥煤的煤质指标、基氏流动度、奥亚膨胀度和镜质体最大反射率进行分析。结果表明,不同变质程度的焦、肥煤具有明显不同的煤质特征,低变质程度肥煤具有高挥发分、高流动度和高膨胀的特点;高变质程度肥煤具有低挥发分、低流动度和低膨胀的特点。同时,通过焦、肥煤的焦炭强度分析,为各焦化和钢厂的配煤炼焦提供依据。     

Influence of the coking properties of coal batch on coke properties

At OAO Zapadno-Sibirskii Metallurgicheskii Kombinat (ZSMK), research is undertaken to improve the optimization of coking batch. The basic approach, proposed by specialists from OAO Nizhne-tagil’skii Metallurgicheskii Kombinat, employs the coefficient K _opt, which characterizes the deviation of the batch from its optimal composition. The coking properties of the OAO ZSMK coal batch over the last few years are analyzed. After laboratory and industrial coking of batch with different K _opt, the strength and reactivity of the resulting coke is investigated. Evaluation of coke-grade coal in terms of its rank according to State Standard GOST 25543-88 proves inadequate, since coal of the same rank may differ markedly in coking properties. A method is established for assessing the optimality of the coal batch at OAO ZSMK.     

Change of pore properties during carbonization of coking coal

Porosimetry, sorption and density measurements are reported on two caking bituminous coals, West Virginia Jewel No. 2 medium volatile and a Pennsylvania Pittsburgh seam high volatile C, for final carbonization temperatures between 400 and 1000°C. Samples were not confined and heating rates of 3 and 8.2°/min were employed. The medium volatile samples exhibit pronounced maxima in pore volume, pore surface area and porosity between 600 and 800°C. These temperatures are considerably greater than the characteristic temperature and the temperature at which maximum dilation occurs. The high volatile C coal does not exhibit well defined maxima. Results are interpreted in terms of pore development mechanisms. A mathematical model for pore development is proposed and shown to correlate satisfactorily, the pore volume and surface area measurements.     

Effects of weathered coal on coking properties and coke quality

Determinations of weathered coal by petrographic methods, and coking tests in an 18-inch ($\text{≈}\text{1}\text{2}\text{m}$) test oven were used to quantify the effects of weathered coal on coking properties and coke quality. The results show that the presence of weathered coal causes a decrease in coke stability and coking rate and an increase in coke reactivity and coke-breeze generation. Because these effects contribute to increased costs in both the coke plant and the blast furnace, every effort should be made to reduce the amount of weathered coal in coking coal mixes.     

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。     

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。     

Rank assignment of coal in terms of its clinkering and coking properties

Comparison of the clinkering and coking properties of coal from different basins indicates that the rank boundaries adopted in State Standard GOST 25543–2013 in terms of the plastic-layer thickness do not correspond to the boundaries in terms of the coking properties. The coal samples are arranged in order in terms of the coking capacity K^cc and the coke-forming capacity K^cfc, and a classification of coal ranks on the basis of the coking properties is proposed.     

Modification of sub-bituminous coal by steam treatment: Caking and coking properties

A Chinese sub-bituminous Shenfu (SF) coal was steam treated under atmospheric pressure and the caking and coking properties of the treated coals were evaluated by caking indexes (G_RI) and crucible coking characterizations. The results show that steam treatment can obviously increase the G_RI of SF coal. When the steam treated coals were used in the coal blends instead of SF raw coal, the micro-strength index (MSI) and particle coke strength after reaction (PSR) of the coke increased, and particle coke reactivity index (PRI) decreased, which are beneficial for metallurgical coke to increase the gas permeability in blast furnace. The quality of the coke obtained from 8% of 200 °C steam treated SF coal in coal blends gets to that of the coke obtained from the standard coal blends, in which there was no SF coal addition in the coal blends. The removal of oxygen groups, especially hydroxyl group thus favoring the breakage of the coal macromolecules and allowing the treated coal formation of much more amount of hydrocarbons, may be responsible for the modified results. The mechanism of the steam treatment was proposed based on the elemental analysis, thermo gravimetric (TG) and FTIR spectrometer characterizations of the steam treated coal.