彬长矿区4号煤层煤质特征及洁净等级划分

为实现彬长矿区优质煤炭资源的清洁高效利用,在对彬长矿区以往勘查钻孔的煤质化验资料统计分析的基础上,系统分析了该矿区主采煤层4号煤的煤岩、煤质特征,论述了硫分、灰分、挥发分、发热量和有害微量元素的分布规律,依据最新煤炭资源潜力评价提出的煤炭洁净等级6级划分方案,选用灰分、硫分、有害元素(F、Cl、As及Pb)6个评价指标对矿区内4号煤层的煤炭资源洁净等级进行了初步划分。彬长矿区4号煤层以低硫、低中灰、中高挥发分、特高热值不黏煤为主,局部含小范围的弱黏煤,彬长矿区4号煤层原煤洁净等级为Ⅲ级,属较好洁净煤;浮煤洁净等级为Ⅱ级,属好洁净煤。整个矿区内4号煤层原煤洁净等级以Ⅲ级较好洁净煤为主,分布区占矿区面积的73.03%,仅在矿区西部洪家镇—巨家镇一带和中东部出现小范围的Ⅳ级中等洁净煤分布区,面积占比为26.97%。     

Petrography and geochemistry of the Middle Devonian coal from Luquan, Yunnan Province, China

Coals from Luquan, Yunnan Province, China, have high contents of cutinite and microsporinite, with an average of 55 and 33.5 vol%, respectively, (on a mineral-free basis). The coals are classified as cutinitic liptobiolith, sporinite-rich durain, cutinite-rich durain, and sporinitic liptobiolith. These four liptinite-rich coals are often interlayered within the coal bed section and vary transversely within the coal bed. The vitrinite content varies from as low as 1.6-20.5% (mineral-free basis), and it is dominated by collodetrinite, collotelinite, and corpogelinite. The maceral composition may be attributed to the type of the peat-forming plant communities. Moreover, the Luquan coals are characterized by high contents of volatile matter, hydrogen, and oxygen, and the high values of the atomic hydrogen to carbon ratio as a result of the maceral composition. As compared with the common Chinese coals and the upper continental crust, the Luquan coals are enriched in Li, B, Cu, Ga, Se, Rb, Mo, Ba, Pb, Bi, and U, with averages of 99.9, 250, 111, 24.4, 4.55, 130, 58.8, 1276, 162, 3.85, and 34.1 μg/g, respectively. The SEM-EDX results show that V, Cr, Ga, and Rb occur mainly in clay minerals, and Cu and Pb are associated with clay minerals and pyrite, and Mo and U are mainly in clay minerals and organic matter. Barite and clay minerals are the main carrier of barium. The high B and U contents are probably resulted from deep seawater influence during coal formation.     

焦作矿区深部煤层赋存及煤岩煤质特征

分析了焦作矿区构造特征和底层分布,说明焦作矿区属典型的华北石炭-二叠系含煤地层,内断层非常发育,多为北东向、近东西向和北西向的正断层。通过对矿区地质分层及目标煤层赋存情况的研究,说明焦作矿区主煤层山西组二1煤层厚度大,分布稳定,属结构简单型煤层;地层自上而下分别为第四系、第三系、上二叠统上石盒子组、下二叠统下石盒子组、山西组及上石炭统太原组。最后对二1煤层煤岩煤质特征进行了分析,结果表明:山西组二1煤属高变质程度无烟煤,宏观煤岩特征为灰黑色,似金属光泽,半暗型,以暗煤为主,亮煤次之,棕色条纹,质轻、污手,块煤为参差状断口,煤芯呈块状、粉状及颗粒状,粒径0.1～1.0 cm。     

贵州省格目底矿区新寨井田可采煤层及煤质特征分析

介绍了格目底矿区新寨井田含煤地层及可采煤层的特点,阐述了其宏观煤岩类型及显微煤岩特征,并通过对新寨井田勘探工作取得的大量基础性资料进行整理,系统分析了新寨井田可采煤层的煤质特征及变化规律,指出了新寨井田煤的工业用途。     

具有突出危险性煤层群煤气共采技术

为保障具有突出危险性煤层群的煤气共采,以谢一矿为试验矿井论证了开采保护层的可行性,并对保护层工作面进行了突出危险区域划分和采用多种方法抽采煤层群瓦斯。试验结果表明：开采保护层并结合多方法的抽采措施后,被保护保护效果及瓦斯抽采效果明显,实现了具有突出危险性煤层群的煤气共采。     

贺西矿4号煤层瓦斯地质规律分析

运用地质构造控制理论,结合区域构造演化特征,通过对贺西煤矿瓦斯地质资料的统计,分析了构造、煤层埋深、上覆地层厚度、顶板泥岩厚度、煤层底板标高、地下水条件等地质因素对瓦斯赋存的影响,得出地质构造、煤层埋深和上覆地层厚度是影响贺西煤矿4号煤层瓦斯含量分布的主控因素,其它地质因素影响煤层瓦斯的局部变化。瓦斯在煤储层中的赋存和分布受地质条件控制,存在明显的瓦斯地质规律。因此,准确掌握贺西矿4号煤层瓦斯地质规律能够为合理进行矿井通风设计、煤层气资源开发利用和瓦斯综合治理提供科学依据,对指导矿井生产具有重要意义。     

Modes of occurrence of fluorine in the Late Paleozoic No. 6 coal from the Haerwusu Surface Mine, Inner Mongolia, China

The No. 6 coal from the Haerwusu Surface Mine, Inner Mongolia, China, is enriched in Al and Ga, which are valuable metal resources that could be extracted from fly ash. However, fluorine in the coal is unusually high (mean 286 μg/g) and potentially toxic to the environment in the extraction process. In this paper, a sequential extraction/density separation procedure (SE/DS) was designed to examine the modes of occurrence of fluorine in the coal. The results show that fluorine extracted in distilled water, NH₄Ac (1 mol/l), and HCl (0.5%) leachates is low, and that in sulfide fraction is below the detection limit. The organic and silicate associations are inferred to account for more than 90% of the total fluorine in the coal. Boehmite and kaolinite are prime carriers of fluorine (the fluorine content in silicate fraction of the boehmite-enriched sample H-14 is up to 1906 μg/g, and that of the kaolinite-enriched sample H-29 is 384 μg/g). In bench samples H-2 and H-3, a minor amount of fluorine is related to goyazite. The relationship between fluorine and boehmite indicates that they were probably derived from the sediment source region, the weathered bauxite of the uplifted Benxi Formation situated to the northeastern Jungar coalfield.     

特厚煤层大采高综放工作面煤壁片帮机理及控制

分析了工作面相关情况,研究了片帮形式、片帮机理等,主要包括拉裂式片帮、剪切式片帮、重力影响式片帮。对煤壁片帮的相关影响因素实行了分析,发现影响因素包括超前支撑压力、煤层特性,及割煤高度、支护状态等。最后,对特厚煤层大采高综放工作面煤壁片帮控制对策进行了探究,并联系实际状况实行特厚煤层大采高综放工作面煤壁片帮控制工作。     

Comparison of fractions of pyridine extract and solvent-refined coal from Illinois No. 6 coal

A pyridine extract of Illinois No. 6 coal and a solvent-refined coal from the same coal have been fractionated. Parallels between the two sets of fractions in composition and molecular weight and some experiments on phenol-pyridine interactions lead to the conclusion that solvent refining cleaves ether links and removes much of the organic 0 and S, without much change in acidic and basic groups. Gel-permeation chromatograms of the fractions indicate that they have moderately narrow molecular weight distributions. A plot of number-average molecular weights against retention times for both sets of fractions gives a smooth curve that is consistent with relations for polystyrene and poly(ethylene oxide).     

Distribution of trace elements in coal from the Powhatan No. 6 mine,Ohio

Size and density separates of low-temperature-ashed coal from the Powhatan No. 6 mine, Ohio, have been used to determine the mode of occurrence of 28 minor and trace elements in coal. The size distribution of the major minerals has been determined, and correlations of trace elements with major minerals have been made. The role of minor minerals in the mode of occurrence of trace elements is also discussed. Instrumental-neutron-activation analysis was used to determine elemental concentrations, and X-ray diffraction and scanning electron microscopy were used for mineral identification.     

Catalytic upgrading of coal liquid vacuum residue derived from Illinois No. 6 coal

Two-stage hydrotreatment under appropriately optimized conditions, including the selection of catalysts and solvents, is very effective for the upgrading of heavy coal liquid residues. A catalyst of high hydrogenation activity and anti-coking nature is desirable for the first, lower temperature stage. Support is to be carefully designed in terms of pore structure and acidity. The coke produced during the hydrotreatment tends to plug intergranular pores of the extruded catalyst. Grinding enhances the activity of the extruded catalyst. The removal of coke precursor and minerals by solvent extraction is also helpful for maintaining catalyst activity.     

Trace element compositions of coal,shale, and petroleum from various sedimentary basins

The concentrations of trace elements in caustobioliths from particular deposits in various coal, shale, and oil-and-gas bearing basins with different ages of bearing deposits and geostructural types are considered. The degrees of trace element concentration by the caustobioliths and their mineral matter were calculated with reference to Clarke numbers in clay rocks. Typomorphic trace elements were separated, and trace elements were classified by concentration factors in caustobioliths from deposits in platform and geosynclinal basins. Considerable differences in the characters of concentration of typomorphic elements in these caustobioliths were revealed.     

Trace element geochemistry of the Obed Mountain deposit coals, Alberta, Canada

This study reports on the elemental concentrations and vertical variation of coal seams from the Obed Mountain deposit, Alberta Foothills, Canada. Results from two sections of Seam 1 show that the major elements (i.e. Al, Fe, Mg, K, Na, Ti, and Si) have high concentrations in intervals having high ash content, with the only exception of Ca. Similarities are apparent, in both sections, in the vertical variations of Th, U, Se, and Zn; Rb, Cs, and K; Sb, Mo, and W; Mn and Sr; and Ba, Cr, Co, Hf, and Sc. These similarities are also evident among the REEs, notably between Ce and La; also between Dy, Eu, and Sm. Most elements, with the exception of Ba and Sr are slightly more concentrated in Section 2 of Seam 1, located approximately 1.5Fig. km away from Section 1. Compared to Seam 1, Seam 2 has lower mean concentrations of elements. Boron in the coal ranges from 27 to 100 ppmw, though most values are less than 50 ppmw. Boron concentrations suggest a freshwater depositional environment. The element is depleted in the sedimentary partings (12–29 ppmw only) and is enriched in the coal interval near the roof and immediately beneath the partings. This enrichment shows possible downward mobilization of boron. Vertical variations of elements are helpful in delineating the boundaries between coal and sedimentary partings in the succession. The Obed Mountain coals are “clean” by world standards and their elemental concentrations are comparable with those in coals of a lower rank from the same coal formation used for power generation in Alberta. All sedimentary partings have low concentrations of Ba, Hf, Sc, Sr, Ta, Th, U, and REEs; this, along with the absence of an Eu negative anomaly suggests a non-volcanic origin for the partings.     

Geology, geochemistry and biomarker evaluation of Lafia-Obi coal, Benue Trough, Nigeria

Lafia-Obi coals from four boreholes were investigated in this study to ascertain their sedimentological and geochemical characteristics. This data enables the proper evaluation of their oil source rock potential and industrial utilization. The Lafia-Obi area is underlain by rhythmic sequences of shale, sandstone and limestone with varying thicknesses of interbedded coal, inferring deposition under shallow marine conditions. The ash and moisture contents of the coal are high suggesting good potential for use in the steel industry. The relatively low volatiles and high vitrinite/inertinite contents indicate that the coal has an appreciable coking quality. Although the total organic carbon content exceeds the kerogen threshold of 0.5 wt% for generation of crude oil, the high vitrinite reflectance values (R₀>1.0%) and several geochemical maturity indices indicate mature to overmature facies. The bitumen compositions also reflect full maturity. The geological and geochemical characteristics of the Lafia-Obi coals are compared and contrasted with those of Enugu coals, with emphasis on the possible economic applications of the former.     

Sulfur transfers from pyrolysis and gasification of direct liquefaction residue of Shenhua coal

The sulfur transformation during pyrolysis and gasification of Shenhua direct liquefaction residue was studied and the release of H₂S and COS during the process was examined. For comparison, the sulfur transfer of Shenhua coal during pyrolysis and that of pyrolyzed char during gasification were also studied. The residue was pyrolyzed at 10 °C /min to 950 °C. During pyrolysis about 33.6% of sulfur was removed from the residue, among which 32.1% was formed H₂S in gas and 1.5% was transferred into tar, 66.4% of the sulfur was remained in residue char. Compared with coal, the residue has generated more H₂S due to presence of Fe_1−xS which was enriched in residue during liquefaction process. There is a few COS produced at 400-500 °C during pyrolysis of coal, but it was not detected form pyrolysis of the residue. During CO₂ gasification, compared with pyrolysis and steam gasification, there are more COS and less H₂S formation, because CO could react with sulfide to form COS. During steam gasification only H₂S was produced and no COS detected, because H₂ has stronger reducibility to form H₂S than CO. After steam gasification no sulfur was detected in the gasification residue. The XRD patterns show after steam gasification, only Fe₃O₄ is remained in the gasification residue. This indicates that the catalyst added during the liquefaction of coal completely reacted with steam, resulting in the formation of H₂ and Fe₃O₄.     

The inorganic geochemistry of coal,petroleum, and their gasification/combustion products

The inorganic makeup of coal and petroleum differ in several crucial ways. The origins of these differences include the disparate geologic environments of formation, the contrasting parent materials (plant versus planktonic) and hence distinct organic species, and the physical state of the fuels (solid versus liquid). The inorganic chemistry of petroleum is usually controlled by the type and abundance of its organic compounds (i.e., V, Ni, ± Fe-bearing porphyrins and S-bearing thiols, sulfides, disulfides, thiophenic derivatives, resins, and asphaltenes), with significant, though often smaller contributions from entrained mineral phases. This near balance of inorganic compositional control causes petroleum to form combustion/gasification (pyrochemical) slag and ash with a large number of elements (i.e., V, Ni, S, Fe, Ca, Na, K, Mg, Si, and Al) in significant relative concentrations. This balance provides also opportunities for large departures from any given “norm”. The inorganic chemistry of coal, on the other hand, is dominantly controlled by its contained detrital and authigenic mineral matter, with relatively small contributions from organically carried elements other than sulfur. Detrital minerals are those that survive the geological processes of weathering and transport, and hence are a small group of physically resistant and chemically stable minerals including quartz, clay minerals, and oxides of Fe and Ti. The most abundant authigenic minerals in coal include clay minerals, pyrite/marcasite, carbonates, Ca- and Fe-sulfates, and Fe-oxides and hydroxides. Pyrochemical slag and ash from coal are therefore primarily enriched in Si, Al, Ca, Fe, and S. From a processing standpoint, the behavior of slag and fly ash is largely a function of the complexity of the fuel's inorganic chemistry (including the original mode of occurrence of the various elements), and the observed oxygen fugacity. Pyrochemical environments vary from reducing to oxidizing as a result of proximity to the flame and operational mode (combustion versus gasification). Consequently, multivalent elements further contribute to the complexity of slag/ash behavior by essentially behaving as separately unique elements when in their various valence states. In coal, the two abundant, multivalent inorganic elements are Fe (0, + 2, and +3) and S (−2, 0, +2, +4, and +6). In petroleum there are four abundant, multivalent inorganic elements: Ni (0 or +2), Fe (0, +2, and +3), V (+2, +3, +4, and +5), and S (−2, 0, +2, +4, and +6). The larger number of abundant inorganic elements in petroleum than coal, as well as the broader range of associated valence states, leads to more diverse slag/ash species formed during petroleum combustion/gasification, and consequently less predictable slag/ash behavior. A phase characterization of slags produced by the gasification of petroleum coke (a petroleum refining byproduct) illustrates their increased complexity with respect to typical coal slags.     

Effects of coal cleaning on the short contact time liquefaction of Illinois No. 6 coal

This study was carried out to determine the effect of coal cleaning by oil agglomeration and sink-float methods on yields from short contact time liquefaction of Illinois No. 6 coal. The runs were made in a continuous unit using SRC-II distillates as process solvent. Measured yields included hydrogen (consumption), hydrocarbon gas, distillate oil, SRC (the pyridine-soluble portion of the residue) and insoluble organic matter, the pyridine-insoluble organic residue. The solubility of product SRC in hexane, toluene and pyridine was also determined. The principal finding was that coal cleaning by density methods reduced the yield of IOM obtained in subsequent liquefaction and this is attributed to the removal of inert components from the feed coal. In addition, cleaning which significantly reduced pyrite content of the feed coal also reduced the yield of distillate oil and tended to give a less soluble SRC during liquefaction. Deep cleaning by gravity methods gave the lowest IOM, but reduced pyrite content to the point where distillate oil was consumed rather than produced. Oil agglomeration reduced total ash to 50% of that in the run-of-mine coal, but left the pyrite level in the coal high. The relevance of these results to two-stage liquefaction is discussed.     

六盘水矿区煤炭及煤化工产业发展的思考

本文分析了造成六盘水矿区煤炭及煤化工产业不景气的原因,并就如何促进该地区煤炭及煤化工产业的发展给出了一些建议。     

The wettability of coal and its relevance to the control of dust during coal mining

Water sprays are used on longwall mining machines to help control respirable coal dust during underground mining operations. Surfactant reagents added to the sprays, if properly selected, can improve the coal dust wettability and capture efficiency of water droplets. Combining water-soluble polymers with a surfactant can improve dust suppression further by altering the adhesion-cohesion properties of water droplets. The mechanism of coal dust control using a surfactant-polymer reagent is discussed. The Bureau of Mines tested an anionic surfactant-polyethylene oxide polymer water spray additive in the laboratory and in an underground longwall coal-mining operation. The results were encouraging but anomalously high headgate dust concentrations were consistently observed when the surfactant-polymer reagent was injected during the longwall tests. A hypothesis, based on rheological considerations and an adaptation of the Good-Islam liquid bridge model, is suggested to explain the phenomenon. A brief example of the method for correcting the mine dust concentration data for the excess headgate dust is given.