Optimum active and inert ratios for different metamorphic grade coals

In order to quantitatively describe the difference of optimum active and inert ratio of various metamorphic grade coking coals, the rule of coke micro-strength index （MSI）, determinated by adding different proportions of inert content to ten kinds of single coal, changing with active and inert ratio has been investigated. Three kinds of change rule of the MSI of ten kinds of single coal changing with active and inert ratio have been obtained in the research. It has been demonstrated that Gauss curve model is the optimal model to describe the optimum active and inert ratio of different metamorphic grade coals. On this basis, the optimum active and inert ratio of different metamorphic grade coals can be given.

Relationship between Thermal Metamorphism of Coal and the Periodic Variation Law of Geochemical Behavior of Elements:A Study on the C2 Coal Seam in the Fengfeng Mining Area of the Handan Coalfield in Hebei,China

This study highlights the response of the periodic variation of the geochemical behavior of elements to the thermal metamorphism of coal by considering the differentiation mode and differentiation degree of elements of the C2 coal seam in the Fengfeng mining area of the Handan Coalfield in Hebei,China.The periodic variation of the geochemical behavior of elements was observed to change towards a certain direction as the degree of metamorphism of a geological body increased.Based on the coincidence degree(or similarity degree)between the geochemical behavior of elements and periodic variation of elements,the 57 elements in this study were divided into two levels.The periodic variation of the geochemical behavior of first-level elements was largely synchronous with that of their first ionization energy,suggesting that only one differentiation mode exists and the elements are mainly inorganically associated.The differentiation mode of the second-level elements deviated to a certain extent from their first ionization energy;the larger the deviation,the more complicated and diverse was the differentiation mode.Among the second-level elements,the grade of coal metamorphism has evident and intuitive effects on the proportion of elements with particular structural features,such as the 4q+3 type of elements and the odd-odd elements.In addition,the distribution of elements in organic and inorganic matter within coal are subject to the structural features of the elements.The differentiation mode and differentiation intensity of elements could be characterized by the hierarchical parameter and differentiation intensity.The hierarchical parameter and differentiation intensity of certain elements showed a good positive or negative correlation with R_(max) in coal.The 57 elements in this study were quantitatively ordered according to the degree of magmatic hydrothermal fluid influence and thermal metamorphism of coal through graphs depicting the goodness of fit,correlation coefficient with R_(max),and differentiation intensity.The results of this study are consistent with the results of previous field research,illustrating the scientific significance and application value of this study on the periodic variation of the geochemical behavior of elements.

Characteristics of Telemagmatic Metamorphism of the Ceshui Formation Coal in Lianyuan Coal Basin

The Ceshui Formation coal is mostly anthracite and its metamorphism has been lessdocumented. By analyzing systematically the reflectance of vitrinite and the results of X-raydiffraction of the Ceshui Formation coal in the Lianyuan coal basin, the spatial variation characteristics of coal ranks, coal metamorphic regions, the extension of coal metamorphic beltS, coalmetamorphic gradients, coal chemical structure and the effect on the degree of metarnorphismof heat-prediction and -storage conditions, babied depth Of the Indosinian-Yenshanian granitesat the margins of the Lianyuan coal basin are discussed. The research results in conjunction ofthe features of regional hydrothermal alterations, endogenetic deceits with the Ceshui Formation coal measures, and the development of secondary vesicles indicate that the telemagmaticmetamorphism is the main factor leading to the metamorphism of the Ceshui Formation coal inthe region studied.

Genesis of Coal Metamorphism of Late PalaeozoicCoals in the South of North China——A Further Approach to the Effects of ThermalGroundwater on Coal Metamorphism

The close relationship between the genesis of coal metamorphism and the evolution of the regional tectonic framework is expounded on the basis of an analysis of the geological factors causing the metamorphic zonation of the Late Palaeozoic coals in southern North China; in terms of the mechanism for the formation of palaeogeothermal anomalies, the effects of thermal groundwater on coal metamorphism is highlighted and a geological model for thermal groundwater metamorphism of coal established; with the concept of the palaeogeotherm-coal metamorphism system, the genesis of coal metamorphism is analysed according to the distribution pattern of three geological factors: heat source, heat-carrier and channel, and heat-collector.

Coal Deformation, Metamorphism and Tectonic Environment in Xinhua, Hunan

This article discusses in detail chemical composition, molecular structure, microstructure phenomena, estimate of the palaeo-stress, paleo-temperature and the strain rate to deepen the knowledge for the correlation of coal deformation and metamorphism with structural environment in Xinhua Hunan by coal quality analysis, XRD and SEM methods, which provide dependable theoretical foundation for coal resource exploitation and utilization. The results show that 1) d002 value of six coal samples is from 3.36 to 3.39 nm, coal resolved itself into aphanitic graphite with the increase of coal rank during coalification, which is characterized by graphite flakes, and the crystallite size is from 50 nm to 250 nm;A certain degree of 3R-structure content is increases and the crystallite size is extend with the coalification process, but RH-structure content is decreased;2) the tectonic environment of research area belongs to the ductile-brittle deformation, which was characterized by low temperature, low stress, high strain rate;3) Tianlongshan magmatic intrusion provided heat source, its side-extrusion made the molecules structure of coal ordering, distance between layers decreased, finally it caused the formation of aphanitic graphite.

不同变质程度煤中镜质组的元素分布特征:基于Raman和原位微区XRF分析

为明确煤中元素与有机质之间的关系,本文选择山西太原西山煤田6个矿区石炭系—二叠系太原组8号煤层煤样(镜质体最大反射率为1.26%~2.03%)为研究对象,挑选其中的镜煤条带,利用激光共聚焦拉曼光谱仪(Raman)选出镜质组,结合微区X射线荧光光谱仪(μ-XRF)对镜质组中元素含量和分布特征进行分析,试图探讨不同变质程度煤中镜质组的拉曼光谱和元素的耦合关系。研究发现,镜质组中仍然存在着大量的纳米级矿物,在实验操作过程中即使Raman光谱的结果限定了有机组分,但是由于束斑大小的差异,μ-XRF测试时不可避免的受到了煤中纳米级矿物的影响;Al、Si、K、Ti、V、Fe、Co、Ca主要赋存于镜质组中的纳米级矿物中,Ni、Zn、Ga、Ge、Br、S则主要以有机结合态的形式存在。

煤的气化反应性与其组成的关系研究

为探究不同变质程度煤的气化反应性,采用下落式固定床反应器,以CO_(2)为气化剂,对11种不同变质程度煤的气化反应性进行了实验研究,考察了煤的气化反应性与挥发分、固定碳、碳含量及灰组成的相互关系。研究结果表明,在1 400℃下,11种不同变质程度煤的气化反应性仍有较为明显的差异,低变质程度煤的气化反应性远高于中/高变质程度煤的气化反应性,其完全气化反应所需时间和气化反应指数最大有7倍之差;从工业分析和元素分析看,挥发分、固定碳和碳含量与煤气化反应性均具有较好的相关性,相关系数为0.88以上;从灰组成分析看,碱性指数与煤气化反应性相关性较差。为此,可根据煤的挥发分、固定碳和碳含量等组成信息预测煤气化反应性的优劣,为煤气化应用提供参考。

低变质煤CO来源及防控技术研究

为了研究低变质煤CO来源,降低煤层自然发火风险;以大南湖一矿3#煤层为研究对象,通过程序升温实验、实验模拟及现场观测等手段,研究3#煤层CO赋存、开采及割煤中CO产生规律及回风隅角CO来源占比等规律。结果表明:煤在无氧下粉碎,煤分子共价键断裂生成的大量官能团、自由基相互作用产生极少量CO;煤在有氧下粉碎,产生大量CO,随煤样比表面积增大,CO体积分数随之增加并最终趋于稳定;采煤机割煤中产生高温使煤体发生氧化产生CO体积分数为(30~50)×10^(-6);回风隅角CO来源于采空区的CO体积分数占回风隅角CO总体积分数的28%,70%以上的CO来源于生产时期后溜破碎煤体氧化。根据低变质煤CO来源,采取了有针对性的架后喷洒CO复合抑制剂、采空区压注冷氮及漏风封堵等综合防控措施,使回风隅角及回风流CO体积分数大幅降低。

煤变质作用的构造物理化学机理实验研究进展

煤作为对温度、压力等地质环境条件极敏感的有机岩,地质历史演化过程中各种构造-热事件必然导致煤发生一系列物理、化学、结构和构造变化,物理模拟实验则是揭示煤变质作用机理的重要手段。本文基于煤变质热模拟实验、高温高压模拟实验方面的研究成果,着重对煤变质作用机理、演化进程及煤变质作用模拟实验的应用和发展趋势进行阐述。煤变质作用包含煤化作用和石墨化作用两个阶段,体现为多尺度、多阶段的物理化学结构演化,基本特征趋向于分子结构有序化和化学成分单一化。温度是煤变质的主导因素,而力的作用方式同样约束着煤变质作用。热模拟实验基于“时间-温度补偿原理”,采用开放、半开放和封闭等不同实验体系,模拟不同温压条件和构造-热环境下的热解过程。高温高压模拟实验基于相似性原理,在热模拟基础上加入压力变量,模拟不同温压条件和应力-应变环境,以全面模拟煤在各种构造物理化学条件下所发生的物理化学变化,探究不同温压耦合条件下煤变质作用机理、影响因素与演化途径。煤变质的热模拟及高温高压模拟实验在油气生成、煤储层评价、煤成石墨化及煤中战略性金属元素迁移等多个领域得到广泛应用,今后将朝多学科交叉融合和多场耦合模拟实验方向发展,以期更精确地模拟地层构造作用下的复杂地质条件,为深入探究煤变质作用的构造物理化学机理提供更有效的技术手段。

烧变岩矿物相特征及其转化

【目的】烧变岩作为一类由煤层自燃烘烤围岩形成的特殊岩石,在鄂尔多斯盆地东北缘延安组广泛发育,该类岩石中烧变相关的矿物相特征及形成机理尚不清楚。【方法】对陕西张家峁煤矿井下烧变岩进行分析测试和原岩高温加热模拟,进行烧变岩矿物相特征分析。【结果和结论】研究发现:井下烧变岩中铁镁质成分富集,Zn、Rb、Sr、Zr等微量元素相较原岩异常迁移,稀土元素Eu迁出,La/Yb−ΣREE分配模式更接近花岗岩。显微镜下烧变岩发育绿泥石化、磁铁矿化和赤铁矿化,发育变余结构和矿物烧熔现象,同时发育高温变质结晶矿物,如方石英、鳞石英、莫来石和堇青石。烧变岩变质作用类型主要为重结晶作用和熔融作用,缺少典型热变质岩中的交代蚀变或同化混染作用,也不发育含水或含羟基矿物,这种特征可能是由于烧变作用条件为近地表低压和开放环境,其变质作用体系内无H2O流体作用于矿物间的物质交换。结合烧变作用条件和矿物组合特征,认为烧变作用是不同于其他热变质作用的特殊变质类型。综合前人和本次研究,将烧变岩变质相作为一类特殊的热接触变质作用提出,按变质温度由低到高将其分为4个阶段:(1)低温脱水相阶段(绿泥石化、含水矿物被破坏)、(2)中温氧化相阶段(磁铁矿化、赤铁矿化)、(3)高温烧熔相阶段(莫来石、堇青石、方石英和鳞石英)、(4)完全熔融相阶段(辉石、假玻璃质长石)。研究对烧变岩矿物相及其转化做了系统总结,并在变质岩相系及其变质条件研究的基础上总结烧变相系,认为温度和近地表低压开放体系是不同烧变岩相形成的原因。

不同变质程度煤体微孔多重分形特征研究

为研究不同变质程度煤体微孔孔径多重分形的特征,根据低温液氮吸附实验数据,运用多重分形理论对4种不同变质煤体样品微孔的多重分形特征、以及孔隙特征与变质程度之间的关联展开研究。结果表明:4种煤样微孔均具备了多重分形的典型特征,变质程度越高煤样的微孔分布非均质性越强,其微小孔拥有更大的比表面积,将会为瓦斯气体提供更多的吸附位,拥有更大的解吸量;4种煤样的微孔孔径多分布在孔隙空间较为狭小的区域中,约为7~9 nm;微孔结构在弱变形作用下的非均质性明显,在此区域内,较大的孔径分布均一;但从整体看,其连通性与变质程度关系不明显且孔隙以聚集和分布不均匀为主导。

低变质程度煤层自然发火标志气体预警值和临界值确定

低变质程度煤层中具有较多活性基团,活性基团使煤层具有低温氧化特性,煤矿生产过程中,低变质程度煤层采煤工作面回风隅角CO体积浓度较高。为确定低变质程度煤层自然发火标志气体预警值和临界值,建立了采空区内部温度分布和回风隅角CO体积浓度预测数学模型,以122109工作面为例,利用该模型进行了测试。结果表明:回风隅角自然发火标志气体CO的预警值和临界值分别为94.4×10^(-6)、346.2×10^(-6),根据测试结果建立了煤层自然发火分级预警指标。通过案例测试表明,以采空区内部温度分布为基础的回风隅角CO体积浓度预测模型能很好地应用于低变质程度煤层。

不同变质程度煤氧化特征指标量化分析

为了研究不同变质程度煤氧化特征指标变化规律,采用程序升温实验系统分别对不黏煤(BN)、气肥煤(QF)和1/3焦煤(1/3JM)氧化过程进行了测试分析,确定了不同氧化阶段的表观活化能,量化计算了煤自燃极限参数变化特征。结果表明:低变质程度煤的表观活化能比高变质程度煤的低,BN、QF、1/3JM煤样平均表观活化能分别为39.90、65.28、69.43 kJ/mol,煤的表观活化能与其变质程度呈正相关关系,低变质程度煤自燃危险性更高;同一煤种不同阶段的表观活化能也不相同,BN、QF和1/3JM煤样阶段一表观活化能分别为55.28、75.05、80.79 kJ/mol,阶段三则分别为23.23、59.07、61.50 kJ/mol,整体随氧化反应深入而降低;3个煤种自燃极限参数极值点温度分别为50.3、61.5、59.7℃,低变质程度煤比高变质程度煤的极值点温度要低;相同条件下,低变质程度煤最小浮煤厚度和下限氧气体积分数更小,上限漏风强度更大,更容易发生自燃,而变质程度相近的煤种,其氧化特征参数接近。

不同变质程度煤体表面液滴铺展特性实验研究

为研究不同变质程度煤体表面液滴铺展特性,采用实验与数值计算相结合的方法,通过观察纯水液滴撞击煤体的动态铺展过程,探讨撞击高度对不同变质程度煤表面接触角及液滴铺展系数的影响,揭示不同变质程度煤体的润湿机理。测量4种不同煤质的静态接触角,实验结果表明:褐煤的润湿性最强,肥煤次之,无烟煤和焦煤的润湿性最差;观察纯水液滴碰撞不同煤样的动态变化发现,撞击高度与纯水液滴的铺展系数之间存在正相关关系;在相同高度下,纯水液滴铺展系数的变化均表现为先增大后降低再增大,最终趋于一个稳定状态。该研究结果可为矿井湿式除尘技术提供一定的理论参考。

大黄山一号井地质构造特征及其对煤层瓦斯赋存的影响

为了分析地质构造及其演化对新疆大黄山一号井煤层瓦斯赋存的影响,对井田地质构造及演化特征、含煤地层埋藏-抬升史、煤层变质作用、瓦斯生成与赋存特征等开展研究,为大黄山一号井瓦斯灾害防治提供理论指导。研究表明:井田地处博格达山北缘逆冲推覆构造带之山前弧形逆冲断褶带,受高角度叠瓦状逆冲断层及南北向构造挤压应力控制,井田主体构造表现为一南北翼被NE、NW向共轭走滑平移断层切割的轴面南倾的弧形紧闭倒转向斜。井田含煤地层沉积后主要经历了两个阶段:第Ⅰ阶段为快速沉降,并于晚侏罗世至最大埋深4 000m左右,煤层达到气煤变质阶段,煤层瓦斯大量生成;第Ⅱ阶段为持续挤压抬升形变,煤层瓦斯大量逸散。受切向应变主动褶皱作用控制,井田向斜南北两翼向核部,煤层所受挤压应力越来越大,导致煤层孔隙率、透气性系数愈来愈小,煤层瓦斯含量及瓦斯压力愈来愈高。受东西差异性挤压弧形构造背景控制,北翼西部煤层瓦斯含量及瓦斯压力普遍高于东部,且表现出由西向东逐步降低的趋势。受走滑斜移断层控制,断层附近煤层瓦斯含量及瓦斯压力出现局部高值。

黏煤与气煤对焦炭质量的影响试验研究

为进一步提升焦炭质量,在保证炼焦工艺和设备不变的基础上,可通过对煤粒度调整得到高质量的焦炭。以黏煤和气煤为代表的低变质程度为例,对其在不同破碎粒度条件下的配合煤的G值、Y值以及最终所得焦炭的机械强度和热性能进行对比,得出了低变质程度煤破碎程度与焦炭质量的关系,为后续指导低变质煤的炼焦实践生产具有重要意义。

榆树田煤矿地质构造特征及其对煤层瓦斯赋存的影响

为了明确地质构造特征对新疆榆树田煤矿煤层瓦斯赋存的影响,采用理论分析、数值模拟、数理统计、实验测试等方法对井田地质构造及演化特征、含煤地层埋藏—抬升史、煤层变质作用、瓦斯生成与赋存特征等开展研究,为榆树田煤矿瓦斯灾害防治提供理论指导。研究结果表明,井田构造整体表现为向西倾伏的不对称宽缓向斜,属于切向应变主动褶皱作用模式。井田煤层瓦斯主要经历了3个生成—逸散阶段,煤层所经历最大埋深约2900 m,所经历最高地温超过110℃,煤层瓦斯累计生成量至少50 m^(3)/t,构造抬升造成约80%的煤层瓦斯逸散。受切向应变主动褶皱(向斜)作用及埋深等影响,井田由两翼的低应力—弱应变—高渗透条件逐渐向核部的高应力—强应变—低渗透条件过渡,进而导致煤层瓦斯逸散路径愈来愈长,逸散阻力愈来愈大,煤层瓦斯含量及压力愈来愈高。差异性构造挤压变形作用导致南翼地层相对北翼处于更强的高应力—强应变—低渗透条件,进而导致南翼煤层具有更高的瓦斯逸散阻力、瓦斯含量及压力。

Law of gas production during coal heating oxidation

Coal spontaneous combustion is a great threat to mine safety,and gas is the key index to describe coal spontaneous combustion.Taking the coal samples of different kinds of coal as research object,the temperature programmed oxidation experiment was carried out,and the gases produced by coal samples at different temperatures were collected and analyzed by gas chromatography.This research studied the variation characteristics of gas species and gas concentrations in different coal samples during heating oxidation.The experimental results show that different coal samples produce different kinds of gases in the process of heating and oxidation.The order of gas production is CO,C2H6,C2H4,C3H8,and the relationship between gas production and temperature is approximately exponential.With the increase of coal metamorphic degree,the turning point temperature of sharp rise in coal sample gas production rate become higher,the oxidation ability of coal sample decreases,and the quantity of gas production decreases during the same time period.

Research progress and prospects of coal petrology and coal quality in China

Clean utilization of coal depends on the quality of raw coal,which depends on the coal-forming parent materials(petrology and chemical composition of coal),the multiple media of the coal-forming environment,and some epigenetic conditions,such as thermal evolution(coalification),magmatic hydrothermal fluid,groundwater.Based on the research results of predecessors and prediction studies of coal resources since the founding of China,the present status of research on coal petrology,coal quality,coal metamorphism,and coal geochemistry in China is discussed in detail,with emphasis on research progress and the general situation of highly efficient and clean utilization of coal in the technical fields of coking,pyrolysis,combustion,gasification,and liquefaction,and the development prospects of coal petrology and coal quality in China are prospected.