Research on Permeability of Multiphase Medium of Middle to High-Rank Coals

The permeability of coal of middle to high ranks were tested using He,CH 4 and H 2O in single phase medium and using CH 4 and H 2O in double phase medium. The relation between adsorption and permeability of those media was discussed, and the seepage flow characteristics of methane-water medium in coals were analyzed. The result shows that the coalbed methane resource of high-rank coal reservoirs in China is still recoverable.

Physical simulation of hydrodynamic conditions in high rank coalbed methane reservoir formation

In order to select highly productive and enriched areas of high rank coalbed methane reservoirs, based on hydrologic geology as one of the main factors controlling coalbed methane （CBM） reservoir formations, the effect of hydrodynamic forces controlling CBM reservoir formations was studied by a physical simulation experiment in which we used CBM reservoir simulation facilities. The hydrodynamic conditions of high coal rank reservoirs in the Qinshui basin were analyzed. Our experiment shows the following results： under strong hydrodynamic alternating action, 6C~ of coalbed methane reservoir changed from the start at -2.95% ~ -3.66%, and the lightening process occurred in phases; the CI-I4 volume reduced from 96.35% to 12.42%; the CO2 vo- lume decreased from 0.75% in sample 1 to 0.68% in sample 2, then rose to 1.13% in sample 3; the N2 volume changed from 2.9% in sample 1 to 86.45% in sample 3. On one hand, these changes show the complexity of CBM reservoir formation; on the other hand, they indicate that strong hydrodynamic actions have an unfavorable impact on CBM reservoir formation. It was found that the gas volume and hydrodynamic intensity were negatively correlated and low hydrodynamic flow conditions might result in highly productive and enriched areas of high rank CBM.

Resistivity response to the porosity and permeability of low rank coal

Laojunmiao coal samples from the eastern Junggar basin were studied to understand the relationship between coal resistivity and the physical parameters of coal reservoirs under high temperatures and pressures.Specifically,we analysed the relationship of coal resistivity to porosity and permeability via heating and pressurization experiments.The results indicated that coal resistivity decreases exponentially with increasing pressure.Increasing the temperature decreases the resistivity.The sensitivity of coal resistivity to the confining pressure is worse when the temperature is higher.The resistivity of dry coal samples was linearly related to φ~m.Increasing the temperature decreased the cementation exponent(m).Increasing the confining pressure exponentially decreases the porosity.Decreasing the pressure increases the resistivity and porosity for a constant temperature.Increasing the temperature yields a quadratic relationship between the resistivity and permeability for a constant confining pressure.Based on the Archie formula,we obtained the coupling relationship between coal resistivity and permeability for Laojunmiao coal samples at different temperatures and confining pressures.

Influence of depressurization rate on gas production capacity of high-rank coal in the south of Qinshui Basin, China

A desorption simulation experiment with the condition of simulated strata was designed. The experiment, under different depressurizing rates and the same fluid saturation, was conducted on the sample from 3# coal of Daning coal mine in Jincheng, Shanxi Province. The gas production rate and pressure change at both ends of the sample were studied systematically, and the mechanisms of some phenomena in the experiment were discussed. The experimental results show that, whether at fast or slow depressurizing rate, the methane adsorbed to high-rank coal can effectively desorb and the desorption efficiency can reach above 90%. There is an obvious inflection point on the gas yield curve during the desorption process and it appears after the pressure on the lump of coal reduces below the desorption pressure. The desorption of methane from high-rank coal is mainly driven by differential pressure, and high pressure difference is conducive to fast desorption. In the scenario of fast depressurization, the desorption inflection appears earlier and the gas production rate in the stage of rapid desorption is higher. It is experimentally concluded that the originally recognized strategy of long-term slow CBM production is doubtful and the economic benefit of CBM exploitation from high-rank coal can be effectively improved by rapid drainage and pressure reduction. The field experiment results in pilot blocks of Fanzhuang and Zhengzhuang show that by increasing the drainage depressurization rate, the peak production of gas well would increase greatly, the time of gas well to reach the economic production shortened, the average time for a gas well to reach expected production reduced by half, and the peak gas production is higher.

Volume and Surface Distribution Heterogeneity of Nano-pore in Coal Samples by CO2 and N2 Adsorption Experiments

In this paper,the heterogeneity of adsorption pores in middle and high rank coal samples were analyzed by using low temperature N2 and CO2 adsorption technology and fractal theory.The following results were achieved.1)According to the results of volume and surface fractal dimension,meso-pores can be classified into Mep-1,Mep-2,and Mep-3,respectively.Micro-pore can be classified into Mip-1,Mip-2,and Mip-3,respectively.2)Pore types play an important role in affecting the heterogeneity of meso-pores.The volume heterogeneity(VHY)of Mep-1 is simpler than that of Mep-2 and Mep-3 in type A samples.However,the VHY of Mep-1 becomes gradually larger than that of Mep-2 and Mep-3 from type A to type B and C.The VHY of open pore in the same diameter is higher than that of semi-open or closed pore.Meanwhile,the surface heterogeneity(SHY)of types A and B samples is significantly larger than that of type C,the SHY of semi-open or closed pores is more complicated than that of open pores.3)Coal rank mainly affects the heterogeneity of micro-pores.The heterogeneity of type A is always smaller than that of type B and C.The VHY of Mip-1 is more complicated than that of Mip-2 and Mip-3 in the same samples,and the sensitivity of the VHY of Mip-1 and Mip-2 to the degree of coal rank is smaller than that of Mip-3.Meanwhile,the SHY of Mip-1 and Mip-2 is simpler than that of Mip-3 in the same sample,the SHY of micro-pores remains stable as the pore size decreases,and the affect of coalification level on SHY decreases with the decrease in pore diameter.Full-scale fractal characterization has enabled quantitative characterization of adsorption pore properties and provided useful information with regards to the similarity of pore features in different coal reservoirs.

Jumpy evolution of EPR response of Chinese high-rank coals and its implication to geochemistry

Based upon a series of the coal graphite samples collected from China, the jumpy evolution of the EPR response of the high rank coals was found and its geochemical mechanism was further inquired. The results showed that the makingup, which is activated notably at about 6.0% maximum vitrinite reflectance, might play a principal role in the development of the macromolecular basic structural units in the coals being in the middle to late stage of high rank coalification and that the homologisation of the chemical bonds in the macro molecular structure might provide a geochemical microenvironment for the realization of the makingup.

Triple Medium Physical Model of Post Fracturing High-Rank Coal Reservoir in Southern Qinshui Basin

In this paper, influences on the reservoir permeability, the reservoir architecture and the fluid flow pattern caused by hydraulic fracturing are analyzed. Based on the structure and production fluid flow model of post fracturing high-rank coal reservoir, Warren-Root Model is improved. A new physical model that is more suitable for post fracturing high-rank coal reservoir is established. The results show that the width, the flow conductivity and the permeability of hydraulic fractures are much larger than natural fractures in coal bed reservoir. Hydraulic fracture changes the flow pattern of gas and flow channel to wellbore, thus should be treated as an independent medium. Warrant-Root Model has some limitations and can’t give a comprehensive interpretation of seepage mechanism in post fracturing high-rank coal reservoir. Modified Warrant-Root Model simplifies coal bed reservoir to an ideal system with hydraulic fracture, orthogonal macroscopic fracture and cuboid matrix. Hydraulic fracture is double wing, vertical and symmetric to wellbore. Coal bed reservoir is divided into cuboids by hydraulic fracture and further by macroscopic fractures. Flow behaviors in coal bed reservoir are simplified to three step flows of gas and two step flows of water. The swap mode of methane between coal matrix and macroscopic fractures is pseudo steady fluid channeling. The flow behaviors of methane to wellbore no longer follow Darcy’s Law and are mainly affected by inertia force. The flow pattern of water follows Darcy’s Law. The new physical model is more suitable for post fracturing high-rank coal reservoir.

鄂尔多斯盆地石炭系本溪组煤岩气地质特征与勘探突破

通过对鄂尔多斯盆地石炭系本溪组煤岩分布、煤岩储层特征、煤质特征、煤岩气特征以及煤岩气资源和富集规律等方面开展系统研究,评价其勘探潜力。研究表明:①煤岩气是有别于煤层气的优质天然气资源,在埋深、气源、储层、含气性、碳同位素组成等方面具有独特特征;②本溪组煤岩分布面积达16×10^(4)km^(2),厚度2~25m,以原生结构的光亮和半亮煤为主,挥发分和灰分含量低,煤质好;③中高阶煤岩TOC值为33.49%~86.11%,平均值为75.16%,演化程度高(Ro为1.2%~2.8%),生气能力强,气体稳定碳同位素值高(δ^(13)C_(1)值为-37.6‰~-16.0‰,δ^(13)C_(2)值为-21.7‰~-14.3‰);④深层煤岩发育气孔、有机质孔和无机矿物孔等基质孔隙,与割理、裂缝共同构成良好储集空间,储层孔隙度为0.54%~10.67%,平均值为5.42%,渗透率为(0.001~14.600)×10^(-3)μm^(2),平均值为2.32×10^(-3)μm^(2);⑤纵向上发育5种煤岩气聚散组合,其中煤岩-泥岩聚气组合与煤岩-灰岩聚气组合最为重要,封闭条件好,录井全烃气测峰值高;⑥构建了广覆式分布的中高阶煤岩持续生气、煤岩基质孔和割理裂缝规模储集、源-储一体赋存、致密岩盖层密闭封堵的煤岩气富集模式,存在煤岩侧向尖灭体、透镜体、低幅度构造、鼻状构造和岩性自封闭5种高效聚气类型。⑦依据煤岩气地质特征评价划分出8个区带,估算埋深超过2000m的煤岩气资源量超过12.33×10^(12)m^(3)。上述认识指导风险勘探部署,两口井实施后分别获得工业气流,推动进一步部署预探井和评价井,获得规模突破,提交超万亿方预测储量和超千亿方探明储量,对中国天然气效益增储和高效开发具有重大意义。

超临界CO_(2)作用下高阶煤微观结构及力学特性-声发射特征研究

超临界CO_(2)压裂技术作为极具发展潜力的压裂煤体增透瓦斯技术,明晰其对煤体的影响机制,有助于推动该技术的机理研究和实践工程应用。为准确表征超临界CO_(2)作用下高阶煤的孔裂隙结构及力学特性变化,以焦煤集团中马村矿的高阶煤为试验对象,通过自主搭建的超临界CO_(2)浸泡试验系统,结合全自动物理吸附仪(BET)以及全自动压汞仪(MIP),对超临界CO_(2)处理前后高阶煤的孔裂隙结构变化进行分析,并利用单轴压缩和声发射试验系统对超临界CO_(2)处理前后高阶煤的单轴压缩力学特性和声发射特征进行测定。结果表明:超临界CO_(2)对高阶煤具有良好的扩孔增渗作用。超临界CO_(2)处理后高阶煤的微小孔孔容占比降低,中大孔孔容占比增大,且高阶煤的总孔容增大;超临界CO_(2)对高阶煤的力学特性具有明显的劣化作用。超临界CO_(2)处理后高阶煤单轴抗压强度和弹性模量均显著下降,降幅分别为70.06%和55.56%,且超临界CO_(2)处理后高阶煤的内部声发射信号活跃度明显下降,高阶煤单轴抗压时间、累计振铃计数以及累计能量分别降低了98.68 s、95.14×10^(3)个、200.30 V·ms,降幅分别为46.65%、37.65%、50.03%,高阶煤累计振铃计数以及累计能量平静期占比均显著增加,缓增期占比均降低,激增期前者占比降低,后者占比小幅度增加。研究成果将有助于推动超临界CO_(2)压裂技术的机理研究,对深部高阶煤的煤层气开采和CO_(2)地下封存具有一定指导意义。

高阶煤吸附孔结构特征及其对甲烷吸附能力的影响

孔隙结构对煤层吸附甲烷的能力有显著影响,但目前对高阶煤吸附孔结构特征及其对甲烷吸附能力的影响研究较少。以贵州兴安煤业有限公司糯东煤矿高阶煤样为研究对象,采用低温N2吸附和低温CO_(2)吸附试验,结合分形理论研究了高阶煤吸附孔的孔隙结构特征,并通过高压等温甲烷吸附试验,分析了煤储层物性、孔隙结构特征和分形维数对甲烷吸附能力的影响。结果表明:①高阶煤储层孔隙形态较为单一,多数为两端开放的平行板孔和狭缝型孔,微孔在煤的孔隙结构中占主导地位,其孔体积和孔比表面积占比均大于98%,为气体的富集提供了空间。②以不同孔径段的孔体积占比为权重计算高阶煤孔隙的综合分形维数,微孔分形维数在综合分形维数中占主导地位;煤样孔隙结构具有明显的分形特征,孔隙非均质性较强。③Langmuir模型能很好地描述高阶煤的吸附行为,煤储层物性、孔隙结构和分形维数对甲烷吸附能力影响显著,Langmuir体积与最大镜质体反射率、镜质组含量、灰分含量和水分含量呈线性正相关关系,与惰质组含量呈线性负相关关系;Langmuir体积与吸附孔的孔比表面积和孔体积均呈线性正相关关系,Langmuir体积与分形维数呈弱线性关系。研究结果可为黔西南地区高阶煤层气勘探开发及煤矿瓦斯灾害防治提供理论指导。

高、低阶煤孔隙结构差异性及其对甲烷吸附特性的影响研究

采集沁水盆地高阶煤、二连盆地低阶煤,采用氮气、二氧化碳吸附法对煤基质纳米级吸附孔隙进行测试,分析高低阶煤的储气特征,从而确定影响高、低阶煤煤层气开发的关键因素。研究结果发现,高、低阶煤的比表面积相似,高阶煤的比表面积均值为215.33 m~2/g,可吸附甲烷49.53 cm~3/g;低阶煤的比表面积均值为212.17 m~2/g,可吸附甲烷48.96 cm~3/g。高、低阶煤储气主要为吸附气,占总储气量的99%以上,高阶煤储气主要是微孔吸附气,占总储气量的99.71%;低阶煤不同孔隙均有贡献,微孔最多,占比47.33%,其次是中孔,占比32.644%,大孔最少,占比19.69%。地层水侵入对低阶煤储气量影响大于高阶煤,平衡水条件下,高阶煤可储气量43.46 cm~3/g,低阶煤可储气量33.89 cm~3/g;受微孔特性影响,高阶煤储层储气量较高,但易储难逸,因此煤层气开采的关键问题是疏导微孔吸附气;受中、大孔及亲水性强影响,低阶煤储气量较低,且易储易散,勘察储气聚集区是低阶煤煤层气开发的首要工作。

沁水盆地南部郑庄区块中北部煤层气直井增产新技术研究与应用

为提高沁水盆地郑庄区块中北部煤层气直井产量,基于研究区评价井地应力测试资料、压裂裂缝监测资料,分析了研究区直井增产效果差的原因,提出了针对性增产技术,开展了现场对比试验,并对结果进行了分析,结果表明郑庄中北部直井产量低、措施增产效果差的主因为:①研究区以垂直裂缝为主、压裂缝长较短,且随着埋深增加,相同压裂规模形成的裂缝尺寸减小;②随着埋深增加,支撑剂嵌入深度增加,裂缝闭合加快,导致稳产时间短,产气曲线主体形态为“单峰型”;③经初次压裂后煤体结构更加破碎,新裂缝容易进入初次压裂裂缝,造新缝难度增加。针对上述原因,创新提出的充填预堵+大规模压裂+远端支撑增产技术,“充填预堵”即先采用相对较低的排量、砂比、规模充填初次压裂裂缝,然后再进行大规模重复压裂,实现堵老缝、造新缝。“大规模”压裂即大排量、大液量、高砂比压裂,将压裂液量由600~800 m^(3)提高至1300~2000 m^(3)以上,增加改造体积;将排量由6~8 m^(3)/min提高至10~14 m^(3)/min以上,增加裂缝长度和携砂性能;采用低黏压裂液体系配合低密度支撑剂,将砂比由7%~8%提高至10%~15%以上,提高铺砂强度,降低裂缝闭合程度。“远端支撑”即采用自悬浮支撑剂与大排量相结合,增长支撑剂运移距离,提高支撑裂缝比例。充填预堵+大规模压裂+远端支撑增产技术实施后平均单井日产量达到1380 m^(3),比措施前增产1190 m^(3),比邻井稳产气量增加近1000 m^(3),实现了郑庄中北部中深储层连片低产区直井产量突破。现场对比试验表明:实施“充填预堵”后再进行大规模压裂,平均净施工压力比初次压裂增加了3.3 MPa,形成了新裂缝,比直接进行大规模压裂增量提高1000 m^(3)。总体上,充填预堵+大规模压裂+远端支撑增产技术关键参数数值越大,增产效果越好。

宁夏煤的分子结构演化特征

以宁夏宁东、贺兰山、宁南和香山等四大煤田不同矿区典型煤样为研究对象,采用X射线衍射、拉曼光谱和傅里叶红外光谱对煤结构进行表征,结合分峰拟合来获取煤结构参数及变化规律。结果表明:低-中煤阶煤光学性质是各向同性的,芳香层片尺寸较小,任意取向;随着煤级的增加,芳香层间距d002值以最快的速率减小,延展度La则加快增长,在Rmax大于2.0%后,d002值变化幅度减缓与堆砌度Lc值增大相对应;在d002<0.3480 nm,拉曼参数ID1/IG、AD1/AD1+G开始线性减小,煤的分子结构中芳香层片尺寸增大,定向性增强,光学性质在平行和垂直于芳香层片方向上呈现各向异性,结构有序化程度增大;随着煤化程度的增高,红外光谱显示脂肪结构含量较低,芳香结构吸收带显著,芳香度参数迅速增大,脂肪烃侧链快速脱落,生烃潜力参数‘A’变小;贺兰山煤田和香山煤田煤叠加了岩浆热作用,变质温度较高,导致芳香环缩合程度增强,芳香烃类物质增多。研究结果对煤的结构演化与煤炭清洁高效利用有一定指导意义。

整合压汞、N_(2)和CO_(2)吸附的中−高阶煤多重分形特征

煤储层孔隙结构多重分形特征控制着煤层气的运移和可持续产出,直接决定了煤层气的开采效率,对煤层气开采具有重要意义。为了研究中−高阶煤孔隙结构多重分形特征及其在煤化作用过程中的演化趋势,针对取自沁水煤田生产矿井的中−高阶煤样,整合高压压汞、低温氮气吸附实验和二氧化碳吸附实验,结合多重分形理论,表征并探究了中−高阶煤储层宏孔(>50 nm)、介孔(2~50 nm)和微孔(<2 nm)的多重分形特征在煤化作用过程中的演化趋势及其影响因素。结果表明,中−高阶煤宏孔、介孔和微孔的广义维数谱(D_(q)−q)和多重分形奇异谱(f(α)−α)均满足多重分形特征,这意味着中−高阶煤宏孔、介孔和微孔均表现出多重分形行为。相对于宏孔和介孔,微孔表现出更大的奇异性指数α_(0)和谱宽(ΔD)与较小的赫斯特指数(Hurst,H),即微孔具有更强的非均质性和更差的孔隙连通性。煤化作用促进了煤中大分子的聚合,使煤储层由宏孔优势型和宏孔−微孔并存型储层转变为更为致密的微孔优势型储层,煤中不同尺度孔隙孔径分布趋于均质化,导致中−高阶煤储层孔隙结构均质性的增强和孔隙连通性的改善。宏孔和微孔体积分数对其相应孔径范围内孔隙结构非均质性分别存在积极和消极的影响,而介孔体积分数并不是介孔孔隙孔径分布非均质性的有效约束。镜质组和惰质组对孔隙孔径分布非均质性表现出相反的影响,镜惰比(V/I)与H之间存在正相关性,与α_(0)之间呈负相关性,富镜质组煤发育更多的微孔从而表现出更强的孔隙结构均质性和较好的孔隙连通性。

中高硫煤NaOH H_(2)O_(2)电解脱硫机理研究

煤的含硫量过高会造成经济损失、环境污染,因此中高硫煤的利用受到了极大制约。为实现煤中硫的绿色高效脱除,研究设计了NaOH-H_(2)O_(2)电解脱硫体系,通过探究不同试验体系、不同试验因素对中高硫煤脱硫率的影响,确定了电解脱硫的最佳工艺条件;通过X-射线衍射(X-ray diffraction,XRD)、傅里叶变换红外光谱(Fourier Transform Infrared Spectrometer,FT-IR)和X-射线光电子能谱(X-ray Photoelectron Spectroscopy,XPS)分析各试验体系下煤中矿物质组分、官能团及硫元素形态变化以探究电解脱硫机理。NaOH-H_(2)O_(2)电解脱硫体系的最佳反应条件是:NaOH浓度为3 mol/L、电流强度为0.75 A、氧化剂30%H_(2)O_(2)的体积为25 mL、电解温度为40℃、电解时间为1 h。脱硫机理为:OH^(-)、H_(2)O_(2)在电解过程中生成了高活性的自由基O^(-)和·OH等,可促使煤中黄铁矿类无机硫被氧化成硫酸盐并进行脱除;硫醇、硫醚和噻吩类有机硫氧化成(亚)砜后,在碱性环境中会被水解为硫酸盐或磺酸类化合物并进行脱除。

基于Zeta电位和FTIR的中高阶煤与天然焦表面电性研究

通过对中高阶煤与天然焦表面电性的研究,可为揭示煤与天然焦电磁辐射机理,判断矿物可浮性和实现不同矿物分离提供基础。为深入了解中高阶煤与天然焦表面电性的差异,分析煤与天然焦表面官能团组成的差异,采用Zeta电位与FTIR分析方法对样品的表面特性进行综合分析,研究其表面电性与主要官能团的耦合关系。结果表明:①煤样的Zeta电位总体为负,天然焦样品的Zeta电位为正,同时随着变质程度的升高,样品表面负电官能团减少,Zeta电位增大;②脱灰后,样品表面负电官能团被破坏,煤与天然焦的Zeta电位均为正,且随着煤变质程度的增加,Zeta电位值减小;③羟基、COOH、C=O是影响Zeta电位的主要官能团,其中,C=O对Zeta电位的影响大于COOH;羟基-π是羟基结构中影响Zeta电位的主要官能团。研究成果为进一步探究煤与天然焦电磁辐射机理与浮选性提供基础。

压汞法和液氮吸附法在高阶煤孔隙结构表征中的适用性

沁水盆地南部煤储层是中国典型的高阶煤储层,也是我国煤层气开采的重要基地,其煤孔隙结构表征对煤层气开采、CO_(2)封存及瓦斯突出危险性评价等至关重要。选取沁水盆地样品,采用压汞法和液氮吸附法分别对煤样孔径分布和孔隙形态进行了测试计算。结果表明:相比压汞法,氮气吸附法所测孔体积随孔径的变化率随孔径增加而缓慢上升,孔径所对应的dV/dlgD-D值低,其结果更符合高阶煤微小孔径特征;对比采用压汞法和液氮吸附法所测试的孔隙形态,并结合测量孔径值和典型矿区高阶煤孔隙特点,发现采用液氮吸附法所测得的孔隙形状可以更好地表征高阶煤微小孔径特点。因此,高阶煤孔径5~50 nm孔隙结构表征宜采用液氮吸附法。该研究结果为沁南盆地南部高煤阶孔隙结构精细表征提供了理论依据和实践经验。

高瓦斯中硬煤层超高压水力割缝卸压增透技术及应用

为了提高高瓦斯中硬煤层卸压增透及瓦斯抽采效果,研究了顺层长钻孔超高压水力割缝技术,分析了其卸压增透机理,开展了超高压水力割缝现场试验,确定了等效割缝半径和有效瓦斯抽采半径,考察了超高压水力割缝技术的应用效果。研究结果表明:超高压水力割缝技术具有切割速度快、切割半径大等特点,相当于在钻孔周围煤体开采极薄保护层,平均单刀割缝时间9 min,单刀出煤量0.32~0.42 t,等效割缝半径为1.55~1.78 m;超高压水力割缝组单孔平均抽采浓度76.5%,单孔平均抽采纯量为0.089 m^(3)/min,分别是普通钻孔的4.58倍和4.05倍,是水力冲孔的1.2倍和1.43倍,可见该技术可以大幅度提高卸压增透及瓦斯抽采效果。

基于液氮吸附实验的高阶煤微观孔隙结构特征研究——以川南筠连地区上二叠统乐平组为例

川南筠连地区作为中国南方首个煤层气商业生产基地,产气层位为上二叠统乐平组,系统开展储层微观孔隙结构特征研究对明确煤层气赋存成藏特征具有重要意义。针对乐平组煤层气评价井煤岩心样品进行了扫描电镜观察和液氮吸附实验,从孔隙成因类型、孔隙结构、孔隙形态及其甲烷吸附性能等方面对微纳米级孔隙发育特征进行了系统分析。结果表明:煤岩微观孔隙可划分为植物组织孔、气孔、矿物铸模孔和晶间孔等4种成因类型。液氮吸附实验BET总孔比表面积平均为2.638 m^(2)/g,BJH总孔体积平均为0.003 7 cm^(3)/g,且两者具有良好的正相关性。BJH平均孔径为5.775~17.842 nm,对总孔比表面积起到主要贡献的为孔径<5 nm的孔隙,对总孔体积具有明显贡献的主要为孔径≥10 nm的孔隙。根据孔径将孔隙划分为:微孔(<5 nm)、小孔(5~10 nm)、中孔(10~100 nm)、大孔(≥100 nm),微孔和小孔是煤中气体吸附的主要空间,进一步推测吸附孔和渗流孔的孔径分界为10 nm。液氮吸附回线可划分为重叠型、半分离半重叠缓降型、半分离半重叠骤降型等3类,并依据回线特征将纳米孔隙形态理想化为开放孔、半封闭孔和墨水瓶状孔等3种模型,各类孔在高阶煤中均有发育。基于具有不同孔隙形态的干燥无灰基煤样甲烷等温吸附实验得到,墨水瓶状孔的甲烷吸附能力最大,半封闭孔和开放孔的吸附能力近似,但都低于墨水瓶状孔。

中高灰炼焦煤生产高品质83焦的应用实践

为了降低配煤成本,云煤能源安宁分公司使用低价格的中高灰炼焦煤。由于配量过大,导致焦炭CSR严重下降,在总结经验和小焦炉试验的基础上,采用合适的配煤比,消化了库存的中高灰炼焦煤,焦炭CSR达到≥66.0%的要求。