Catalytic Activity of the Black Liquor and Calcium Mixture in CO2 Gasification of Fujian Anthracite

CO2 gasification of Fuijian high-metamorphous anthracite with black liquor （BL） and/or mixture of BL and calcium stuff （BL＋Ca） as catalyst was studied by using a thermogravimetry under 750-950℃ at ambient pressure. When the coal was impregnated with an appropriate quantity of Ca and BL mixture, the catalytic activity of CO2 gasification was enhanced obviously. With a loading of 8%Na-BL＋2%Ca, the carbon conversion of three coal samples tested reaches up to 92.9%-99.3% at 950℃ within 30min. The continuous formation of alkali surface compounds such as （[-COM], [-CO2M]） and the presence of exchanged Ca, such as calcium phenolate and calcium carboxylates （COO）2Ca, contribute to the increase in catalytic efficiency, and using BL＋Ca is more efficient than that adding BL only, The homogeneous model and shrinking-core model were applied to correlate the data of conversion with time and to estimate the reaction rate constants under different temperature. The corresponding reaction activation energy （Ea） and pre-exponential factor of three anthracites were estimated. It is found that Ea is in the range from 73.6 to 121.4kJ·mol^-1 in the case of BL＋Ca, and 74.3 to 104.2kJ·mol^-1 when only BL was used as the catalyst, both of which are much less than that from 143.5 to 181.4kJ·mol^-1 if no catalyst used. It is clearly demonstrated that both of BL＋Ca mixture and BL could be the source of cheap and effective catalyst for coal gasification.

Insight into the change in carbon structure and thermodynamics during anthracite transformation into graphite

The thermodynamic and kinetic mechanisms of Taixi anthracite during its graphitization process were explored.To understand the variation trends of carbon arrangement order,microcrystal size,and graphitization degree against temperature during the graphitization process,a series of experiments were performed using Raman spectroscopy and X-ray diffraction(XRD).Subsequently,the influencing factors of the dominant reaction at different temperatures were analyzed using thermodynamics and kinetics.The results showed that the graphitization process of Taixi anthracite can be divided into three stages from the perspective of reaction thermodynamics and kinetics.Temperature played a crucial role in the formation and growth of a graphitic structure.Meanwhile,multivariate mechanisms coexisted in the graphitization process.At ultrahigh temperatures,the defects of synthetic graphite could not be completely eliminated and perfect graphite crystals could not be produced.At low temperatures,the reaction is mainly controlled by dynamics,while at high temperatures,thermodynamics dominates the direction of the reaction.

Insight into the microstructural evolution of anthracite during carbonization-graphitization process from the perspective of materialization

Materialization of coal is one of effective and clean pathways for its utilization. The microstructures of coal-based carbon materials have an important influence on their functional applications. Herein, the microstructural evolution of anthracite in the temperature range of 1000–2800 ℃ was systematically investigated to provide a guidance for the microstructural regulation of coal-based carbon materials.The results indicate that the microstructure of anthracite undergoes an important change during carbonization-graphitization process. As the temperature increases, aromatic layers in anthracite gradually transform into disordered graphite microcrystals and further grow into ordered graphite microcrystals, and then ordered graphite microcrystals are laterally linked to form pseudo-graphite phase and eventually transformed into highly ordered graphite-like sheets. In particular, 2000–2200 ℃ is a critical temperature region for the qualitative change of ordered graphite crystallites to pseudo-graphite phase,in which the relevant structural parameters including stacking height, crystallite lateral size and graphitization degree show a rapid increase. Moreover, both aromaticity and graphitization degree have a linear positive correlation with carbonization-graphitization temperature in a specific temperature range.Besides, after initial carbonization, some defect structures in anthracite such as aliphatic carbon and oxygen-containing functional groups are released in the form of gaseous low-molecular volatiles along with an increased pore structure, and the intermediates derived from minerals could facilitate the conversion of sp^(3) amorphous carbon to sp^(2) graphitic carbon. This work provides a valuable reference for the rational design of microstructure of coal-based carbon materials.

Surface and Hydrogen Sorption Characteristics of Various Activated Carbons Developed from Rat Coal Mine （Zonguldak） and Anthracite

Activated carbon samples were developed from coal samples obtained from a coal mine, rat （Zonguldak, Turkey） and anthracite （Siberia, Russia）, applying pyrolysis in a temperature range of 600-900 ℃ under N2 flow, and activation using chemical agents such as KOH, NH4Cl, ZnCl2 at 650 ℃. Nitrogen adsorption at low temperature （77 K） was used to characterize the activated carbon samples, and their pore structure properties including pore volume, pore diameter and pore size distribution were determined by means of the t-plots and DFT methods. The surface area values were higher for rat coal samples than for anthracite one, and for the rat coal samples treated with KOH ＋ NH4Cl ＋ ZnCl2 at 650 °C [Rat650（2）] there are highest surface area and total pore volume, 315.6 m2·g^-1 and 0.156 ml·g^-1, respectively. The highest value of the hydrogen sorption capacity was found as 0.71% （by mass） for the rat coal sample obtained by KOH ＋ ZnCl2 treatment at 650 °C [Rat650（1）].

Combustion characteristics and kinetics of anthracite with added chlorine

The combustion process of Yangquan anthracite（YQ） with the addition of 0.045wt%, 0.211wt%, 1.026wt%, and 2.982wt% chlorine was investigated using a thermogravimetric method from an ambient temperature to 1173 K in an air atmosphere. Results show that the YQ combustion characteristics are not significantly affected by an increase in chlorine content. Data acquired for combustion conversion are then further processed for kinetic analysis. Average apparent activation energies determined using the model-free method（specifically the KAS method） are 103.025, 110.250, 99.906, and 110.641 k J/mol, respectively, and the optimal kinetic model for describing the combustion process of chlorine-containing YQ is the nucleation kinetic model, as determined by the z（α） master plot method. The mechanism function of the nucleation kinetic model is then employed to estimate the pre-exponential factor, by making use of the compensation effect. The kinetic models to describe chlorine-containing YQ combustion are thus obtained through advanced determination of the optimal mechanism function, average apparent activation energy, and the pre-exponential factor.

Constitutive Relation of Yunjialing Anthracite Under Medium Strain Rate

By means of the split Hopkinson pressure bar （SHPB） testing system, this paper presents a dynamic constitu- tive relation of anthracite at a strain rate of ε =5-85s^-1. Generally, the dynamic stress-strain curve for this kind of anthracite under uni-axial compression has the following four stages： a non-linear loading stage, a plastic yielding stage, a strain-strengthening stage and an unloading breakage stage. Correspondingly, the initial elastic modulus Eb, the yielding strength σs and the ultimate strength σb increase along with an increasing strain rate. The time-dependent elasticity was identified when we analyzed the mechanical properties of anthracite. Based on characteristics of measured dynamic stress-strain curves and an analysis of existing rock dynamic constitutive models, as well as a preparatory simulation, a new visco-elastic damage model has been introduced in this paper. A linear spring is put parallel to two Maxwell units with different relaxation times to express two distinct plastic flows. The damage D is equal to [Eb- E（εi）]/Eb, where Eb is the beginning modulus and the E（εi） is the slope of a connected line between the origin point and any other point on a tested stress-strain curve. In the new constitutive model, one Maxwell unit with low relaxation time φ is used to describe the response of anthracite to a low strain rate, while the other, with a high relaxation time φ describes the response of anthracite to a high strain rate. Simulated stress-strain curves from the new model are consistent with the measured curves.

Characteristics of fissures and pores of anthracite in Jincheng by SEM

Anthracite in Jincheng is a highly metamorphic coal and its system of fissures and pores is differentfrom that of low and medium ranked coal.In order to discover their characteristics,69 samples were collected from 18 CBM wells in Zhengzhuang in Jincheng and their fissures and pores were observed by a Scanning Electron Microscope(SEM).To the naked eyes and by SEM,the pores in the Jincheng anthracite are seen to have abundant mold pores with isolated,shallow and poor connectivity(diameters between 1～50 μm) and few plant tissue pores,gas pores,and solution pores.Most of the fissures are filled with clay minerals or closed;while open fissures are not often visible in the Jincheng coal(aperture between 3～10 μm).These characteristics are determined by the high rank and high vitrinite content of the coal.The existence of too many mold pores and filled fissures does not allow the migration of methane,hence hydraulic fracture stimulation will be required and is an effective method of adding and connecting fissures to enhance CBM production.

Activation of anthracite combustion by copper acetate:mechanism,effect of particle size and introduction method

This paper addressed the efect of copper acetate on the combustion characteristics of anthracite depending on the fractional composition of fuel and additive introduction method.Anthracite was impregnated with 5 wt%of Cu(CH_(3)COO)_(2)by mechanical mixing and incipient wetness impregnation.Four anthracite samples of diferent fraction with d<0.1 mm,d=0.1-0.5 mm,d=0.5-1.0 mm,and d=1.0-2.0 mm were compared.According to EDX mapping,incipient wetness impregnation provides a higher dispersion of the additive and its uniform distribution in the sample.The ignition and combustion characteristics of the modifed anthracite samples were studied by thermal analysis and high-speed video recording of the processes in a combustion chamber(at heating medium temperature of 800℃).It was found that copper acetate increases anthracite reactivity,which was evidenced by decreased onset temperature of combustion(ΔT_(i))by 35-190℃and reduced ignition delay time(Δτ_(i))by 2.1-5.4 s.Copper acetate reduces fuel underburning(on average by 70%)in the ash residue of anthracite and decreases the amount of CO and NO_(x)in gas-phase products(on average by 18.5%and 20.8%,respectively).The mechanism for activation of anthracite combustion by copper acetate is proposed.

The Effects of Blends of Enugu Coal and Anthracite on Tin Smelting Using Nigerian Dogo Na Hauwa Cassiterite

The effects of blending Enugu coal and anthracite on tin smelting using Nigerian Dogo Na Hauwa cassiterite have been studied. The work utilized various blends ranging from 100% to 0% anthracite. The content of the Enugu coal in the blend varied from 5% to 100%. The various tin metal recovery percentage for each batch of smelting using various blends was noted. Anthracite alone had the highest recovery of 71.90% followed by 5% blend of Enugu with anthracite. The result, however, showed that as the Enugu Coal was increased in the blend, the recovery was also decreasing. This equally affected the quality of tin metal recovered by increasing the grade. The work recommended that since the cost of production is the critical issue, 5% - 15% range of Enugu Coal should be used in preparing blends to bring down the cost of imported anthracite which is put at $906.69 per ton. The use of 15% Enugu coal will result in lowering the cost of imported anthracite by $136.0.

Research on super-low-ash anthracite preparation

The fundamental question of super-low-ash coal preparation is how to furthest depress high ash component pollution. A jigging process was used to remove high ash refuse and middling, then a high precision heavy medium cyclone was used to further separate near gravity light material. A two-stage heavy medium cylindrical cyclone with the same separation density was used to increase the precision of separation. The feed was de-slimed and fine-grind coal was added with media to improve the stability of the suspension. The pump frequency conversion timing and an air spring were used to steady the cyclone inlet pressure. Based on a series of study and pilot tests, a 1.00 Mt/a (output) commercial separation system with Ep value under 0.015 was built up. Super low ash (Ad≤2.00%) Taixi Anthracite has been put into commercial production.

Geochemical signatures of potassium metasomatism in anthracite from the Himalayan fold‑thrust belts of Sikkim,India

The present study focuses on the inorganic geochemical features of the bituminous coal samples from the Raniganj and the Jharia Basins,as well as the anthracite samples from the Himalayan fold-thrust belts of Sikkim,India.The SiO_(2)content(48.05 wt%to 65.09 wt%and 35.92 wt%to 50.11 wt%in the bituminous and anthracite samples,respectively)and the ratio of Al_(2)O_(3)/TiO_(2)(6.97 to 17.03 in the bituminous coal samples and 10.34 to 20.07 in the anthracite samples)reveal the intermediate igneous source rock composition of the minerals.The ratio of the K_(2)O/Al_(2)O_(3)in the ash yield of the bituminous coal samples(0.03 to 0.09)may suggest the presence of kaolinite mixed with montmorillonite,while its range in the ash yield of the anthracite samples(0.16 to 0.27)may imply the presence of illite mixed with kaolinite.The chemical index of alteration values may suggest the moderate to strong chemical weathering of the source rock under sub-humid to humid climatic conditions.The plot of the bituminous coal samples in the A–CN–K diagram depicts the traditional weathering trend of parent rocks,but the anthracite samples plot near the illite feld and are a bit ofset from the weathering trend.This may imply the plausible infuences of the potassium-metasomatism at post coalifcation stages,which is further supported by high K_(2)O/Na_(2)O ratio(29.88–80.13).The Fourier transform infrared spectra further reveal the hydroxyl stretching intensity of illite in the anthracite samples substantiating the efect of the epigenetic potassium-metasomatism.The decrease in total kaolinite intensity/compound intensity of quartz and feldspar may provide additional evidence towards this epigenetic event.

山西省早白垩世下地壳地质图:基于镜质组反射率证据的修正

我们已经根据花岗岩的资料编制了一份山西省早白垩世下地壳地质图,本文增加了镜质组反射率资料,重新编制了一份山西省早白垩世下地壳地质图。经过对比,得出了许多新认识。对比说明,在下地壳填图中,镜质组反射率是一个非常有用的资料。镜质组反射率可以记录它形成以后所能够达到的最高温度,是煤田和石油地质部门成熟度测量中广泛应用且可靠的方法之一。镜质组反射率方法对岩石学和矿床学也非常有用,因此可以根据镜质组反射率资料推测深部是否有隐伏岩体以及隐伏岩体的分布和规模,推测下地壳底部是否有地幔上涌以及地幔上涌的分布。利用镜质组反射率分布寻找隐伏岩体,再根据隐伏岩体找矿,是一个找矿的新方法。文中根据山西省镜质组反射率的分布,推测在若干R_(o)>3.0%的地区的深部有可能发现隐伏岩体,其中,祁县隐伏岩体已经被钻探验证所证实。山西省煤矿很多,凡是无烟煤分布区均是寻找隐伏岩体的有利地区。文中还根据镜质组反射率资料对山西省早白垩世下地壳地质图进行了修改,指出山西省中部和南部的深部为大片中生代(主要是早白垩世)花岗岩分布区,也是早白垩世时地幔上涌的区域。根据地层资料和花岗岩资料推测山西省北部(大同以北)为地壳厚度正常区,南部为地壳加厚区(为中国东部高原的一部分)。南部为地幔上涌区,北部无地幔上涌迹象;故南部下地壳为高温榴辉岩相区,北部下地壳为低温榴辉岩相区。地表有矿产分布的区域,下地壳为含流体榴辉岩相区。山西省中部和西部的下地壳可能为榴辉岩相-麻粒岩相过渡区,暗示中国东部高原在山西省可能呈现为向西缓慢下降的趋势。

煤基石墨负极材料的制备及其电化学性能研究

以无烟煤为前驱体,研究了煤化程度、灰分、石墨化温度等对无烟煤石墨化的影响机制以及煤基石墨微观结构与电化学性能之间的“构效”关系。结果表明,煤化程度高的无烟煤有利于煤基石墨的微晶生长,在相同温度下能够达到更高的石墨化程度。太西煤在2400℃石墨化后,石墨化度为80.3%,而晋城煤石墨化度仅为74.5%。无烟煤中的灰分有催化石墨化作用,未脱灰样品在低温下石墨化程度较高,具有较高的首次充放电容量;同时灰分的存在会影响煤基石墨的片层结构,使石墨片层存在褶皱,导致煤基石墨的循环稳定性和倍率性能下降。煤基石墨的石墨化度随温度升高而增加,石墨片层结构逐渐发展,电化学性能得到明显提升。脱灰太西煤经2800℃石墨化处理后所得煤基石墨在0.2 C的首次放电容量达370.8 mAh/g。

W火焰锅炉全烧烟煤一体化改造方案

在役的燃用低挥发分煤W火焰锅炉普遍存在炉效低、NO_(x)排放高、结焦严重等问题,在双碳目标和“三改联动”背景下急需提升可靠性、经济性和环保性。某电厂进口350MW亚临界W火焰锅炉机组实施了全烧烟煤的一体化改造,涵盖制粉系统、燃烧系统、锅炉受热面改造等方面内容。改造后锅炉运行良好,炉膛不结焦,锅炉效率由改造前91.64%提高至94%以上,锅炉出口NO_(x)大幅降低,调峰能力满足30%负荷深度调峰需要,机组总体性能显著提高。

基于分形阶理论的无烟煤蠕变模型设计及数值模拟

分形阶导数可以较好地模拟蠕变模型的加速蠕变阶段。通过设计含损伤无烟煤分级加载蠕变试验,探究不同围压条件下无烟煤蠕变规律;在Bingham体中引入分形阶导数,建立含损伤的分形导数Newton体,用以表征含损伤无烟煤加速蠕变阶段;通过基本元件的串并联组合,建立相适应的蠕变模型;对模型完成三维扩展及有限差分;在FLAC^(3D)内置Burgers本构模型的基础上,完成含损伤无烟煤分形阶蠕变模型的二次开发。结果对比表明,蠕变模型能较好的表征损伤无烟煤各阶段的变化特征。改变含损伤分形导数Newton体的相关参数,可以较好的表征相关模型的加速蠕变阶段。

无烟煤分子模型构建及优化方法研究

为了认识煤的分子结构特征,采用元素分析、^(13)C-核磁共振、傅里叶变换红外光谱等测试方法构建无烟煤大分子模型。研究结果表明:大分子模型中芳香碳以C的2、3环结构为主,确定其模型分子式为C_(193)H_(138)N_(2)O_(7);结构和退火优化后,其分子模型越发紧凑,键角更加弯曲,添加周期边界条件后其体系能量迅速降低,这是由于价电子能中的键伸缩能和非成键能中的范德华能降低所导致的,通过密度模拟得到无烟煤大分子最优模型的密度为1.45 g/cm^(3)。研究结果可为构建煤大分子模型提供参考。

惰气熔融-红外吸收/热导法同时测定无烟煤中氮和氢

首次使用惰气熔融-红外吸收/热导法实现无烟煤中氮、氢元素的同时、快速、准确测定.探究分析条件,发现当称样量为0.0300 g,分析功率为5500 W,氮元素的积分延迟时间为15 s,集成时间为55 s,氢元素的积分延迟时间为5 s,集成时间为85 s,且使用石墨套埚时,氮氢元素的释放最完全、合理.方法中氮、氢校准曲线的相关系数分别为0.9949、0.9940,检出限分别为0.321%、0.189%,定量限分别为0.326%、0.194%,精密度分别为3.60%、0.63%,满足线性关系及方法要求.惰气熔融-红外吸收/热导法重复性好、高效便捷、操作和维护简单,可用于无烟煤中氮、氢元素的定量检测.

活性磁化水改善无烟煤煤尘润湿性能的研究

为了提高活性磁化水抑制无烟煤尘的性能,分别测定了4种表面活性剂溶液的表面张力,进而选取最佳浓度表面活性剂溶液.测定了不同磁化参数下的最佳浓度表面活性剂溶液的表面张力,以确定最优磁化参数.同时分别测定矿井静压水、最佳浓度表面活性剂溶液、最佳活性磁化水与无烟煤的接触角.结果表明,质量分数0.10%尘克C&C溶液可使矿井静压水的表面张力下降43.83%.质量分数0.10%尘克C&C溶液的优磁化强度为300 mT,磁化时间为50 s.相较于矿井静压水,质量分数0.10%尘克C&C活性磁化水接触角减小了79.11%,表面张力减小了47.04%,铺展功及浸湿功分别提升了97.35%、87.01%,极大提升了溶液的铺展能力和浸湿能力.现场应用试验结果表明,使用质量分数0.10%尘克C&C活性磁化水作为采煤工作面的喷雾降水,降尘效率提高了37.53%.

矿物对无烟煤力学非均质性影响的分子动力学研究——以沁水盆地南部主要黏土矿物高岭石为例

煤是由有机显微组分和矿物组成的混合物,矿物的存在会导致煤的大分子结构存在差异,使得煤的力学性质具有明显的非均质性,进而影响区块内整体的煤层气产量、压裂改造效果和成熟技术的规模化应用。以沁水盆地典型的无烟煤和高岭石矿物作为研究对象,通过分子动力学的方法定量研究高岭石及其含量对无烟煤力学性质的影响规律,分析不同矿物含量下无烟煤的分子结构和孔隙特征,从能量和有序化的角度揭示其微观机理。结果表明:①煤有机质与高岭石相互结合过程中同时存在范德华力和氢键作用,且氢键作用强度要高于范德华力,煤有机质周围出现高岭石分子的概率、相互作用强度和有序性均随着矿物质量分数的增加而增大。②无烟煤的孔隙率φ随高岭石质量分数a的增大呈线性规律(φ=−0.2293a+9.6295)降低,而无烟煤的体积模量、弹性模量和剪切模量均随高岭石质量分数的增大呈线性规律增强,泊松比随高岭石质量分数的增大呈二次多项式规律降低。③无烟煤的力学非均质程度整体上随着高岭石质量分数增加而增大,其中不同高岭石质量分数下体积模量、弹性模量和剪切模量的变异性可分为很低、低、中等、高和很高5个部分,而泊松比的变异系数均小于0.1,变异性很低。④随着高岭石质量分数的增加,煤有机质与高岭石的相互作用能呈线性规律(Einteraction=4.5585a+443.929)增大,与纯有机质相比,当高岭石质量分数达到20%时,无烟煤的键能和范德华能分别增加了63.86%和48.06%。⑤高岭石增强煤力学性质的内在原因是高岭石进入煤有机质后占据一定的孔隙空间,且与煤有机质的芳香碳骨架和不同官能团进行相互作用,高岭石质量分数越大充填煤大分子结构孔隙的程度越高,煤大分子结构的能量越大,导致煤大分子结构的孔隙率降低,有序性增大,使得力学强度和抵抗变形的能力增强。

2024年我国无烟煤市场发展与展望

通过对宏观政策以及产业政策动态等多维度进行剖析,对无烟煤下游行业的消费现状和趋势进行详细分析和预测。介绍了我国无烟煤资源分布、生产和进口现状,对我国无烟煤生产和进口趋势进行了预测。综合分析供需、成本、政策等影响无烟煤价格的因素,特别是需求和供应关系,对2024年无烟煤价格走势进行了定性分析。整体认为,2024年,我国无烟煤将处于供需紧平衡状态,但较2023年略有宽松;价格中枢有望小幅下移,但仍将处于相对较高的位置。