煤中可溶有机质对煤的孔隙结构及甲烷吸附特性影响

采用四氢呋喃对临涣7煤和祁南3煤进行微波辅助抽提,进行了原煤和残煤等温吸附实验和低温氮气吸附测试,对比分析了抽提前后原煤和残煤的甲烷吸附量和比表面积、孔分布情况,并理论测算煤中可溶有机质吸附溶解甲烷量.结果表明,残煤的甲烷吸附能力低于原煤;抽提后,煤的比表面积和总孔体积增大,平均孔径减少,影响煤吸附气体能力的主要孔径为1.7~5.0 nm,且该范围内的孔数有不同程度的增加;压力为0.1~5.0 MPa时,两煤样中可溶有机质吸附溶解的甲烷量分别为0.45~4.22 mL/g、0.69~4.99 mL/g,最大吸附量分别占到原煤最大吸附量的30%和38%.分析认为,煤中可溶有机质占据部分煤中孔隙,影响煤孔隙结构,同时,在压力的作用下,甲烷可以溶解和吸附煤中可溶有机质.     

含水量对神府煤快速热解过程气体释放及孔隙结构变化的影响

通过外添加水分改变神府煤含水量,利用高频加热炉进行快速热解,研究了含水量对神府煤快速热解过程的影响,考察了四种含水量神府煤快速热解气相产物分布及变化规律,利用孔/表面分析仪表征了固相产物的结构变化。结果表明,随着煤中含水量升高,热解气总体积和最大释放速率减小;热解焦的比表面积和孔容随含水量升高而增大,与原煤煤焦相比,含水煤制得热解焦中保留了较多小孔,孔隙结构更加发达;水分有利于抑制热解过程孔的阻塞与塌陷,提高煤焦表面的粗糙程度和多孔结构的复杂程度。     

新疆褐煤疏水改性提高其成浆性能

针对新疆褐煤具有较高内水的问题,制备了阴离子AKD改性剂和非离子AKD改性剂,对褐煤颗粒进行疏水改性。研究了改性前后煤粒表面化学成分、孔隙分布、亲疏水性和Zeta电位等煤粒表面特性,并结合NSF分散剂在改性前后煤粒表面吸附量大小,探讨了改性前后褐煤水煤浆的成浆性、流变性和稳定性。结果表明,改性后煤粒孔隙结构降低,煤粒表面碳的相对含量增加,氧的相对含量降低,煤水界面接触角增加,煤粒疏水性能增强。NSF分散剂在改性煤表面吸附量增加,煤粒表面负电性增强。由阴离子AKD改性煤、非离子AKD改性煤制备的水煤浆最大成浆质量分数从原煤56.6%分别增加至61.0%、62.5%,浆体析水率从原煤13.97%分别降低至7.45%、7.89%,同时改性后煤粒制备的浆体均表现出剪切变稀的假塑性流体。因此,改性煤粒更容易制备高浓度、低黏度、高稳定性且易于储存和运输的水煤浆。     

煤粉在热分解过程中比表面积和孔隙结构的变化

用氮气等温吸附（７７Ｋ）方法测量了四种不同煤粉在热分解过程中的ＢＥＴ比表面积和孔隙结构。结果表明，不同煤种的比表面积在热分解过程中其变化有着相似的规律。在热分解温度低于５００℃时，煤粉所释放的挥发份主要来自煤粒外表面。当热分解温度高于５００℃后，煤粉释放出的挥发份主要来自煤粒内部深处。在８００℃时，由于煤的塑性，煤粒的部分孔减小和关闭，使其比表面积以及孔隙明显减少。在热分解温度高于８５０℃后，煤粉的比表面积随温度升高而急剧增大。     

溶剂极性控制下的煤抽余物吸附甲烷能力研究

基于原煤和有机溶剂抽余物的等温吸附实验结果,对比分析溶剂极性与其煤抽余物吸附甲烷能力变化关系,探讨抽提溶剂极性差异对煤抽余物吸附甲烷能力控制的地球化学机理。结果表明,煤溶剂抽余物等温吸附甲烷曲线都遵循Langmuir方程,且二硫化碳(CS₂)和苯(C₆H₆)溶剂抽提作用增大了煤吸附甲烷量,四氢呋喃(THF)和丙酮溶剂抽提作用减小了煤吸附甲烷量。实验发现,煤抽余物吸附甲烷能力变化与抽提溶剂极性成负相关关系,该现象可用相似相容原理解释:CS₂和C₆H₆溶剂极性较弱,抽提出较多具有非极性结构(-CH₃和-CH₂-)的烷烃和芳烃,为甲烷在煤表面吸附增多了吸附位而增强了抽余物吸附甲烷能力,THF和丙酮溶剂极性较强,抽提出较多具有极性结构(-CHO、-OH、和-COOH)的非烃和沥青质,减少了吸附位而降低煤抽余物的甲烷吸附能力。     

煤及其溶剂萃取产物的氮气吸附行为

用二硫化碳-N-甲基-2-吡咯烷酮（CS2-NMP）(1∶1, V/V) 混合溶剂，以及丙酮和吡啶将云南褐煤和南桐烟煤逐级萃取，去除萃取溶剂后得到各级固态级分。通过ASAP 2010型比表面积及孔快速测试仪，对原煤及萃取级分的氮气吸附行为进行测试，分别用BET模型、线型方程对实验结果进行拟合。结果表明对于萃取率较高的煤，溶剂萃取能较大地增加其孔隙率；煤对氮气的吸附行为遵从Henry定律，因此只需在氮气饱和气压的沸点（77 K）下，测出少数几个压力点的吸附量，就可以得到一条准确的等温吸附线。     

先锋褐煤及其热溶残煤的过氧化氢氧解

利用1-甲基萘（1-MN）对先锋褐煤进行热溶,并在温和条件下分别对原煤及其热溶残煤进行过氧化氢氧化。结合元素分析和FT-IR对各级产物进行结构表征,用GC/MS对氧化反应水溶性产物的甲酯化衍生物进行分析。结果表明,先锋褐煤在1-MN中的热溶率较低,320 ℃下热溶残煤（TR）的收率为81.01%,该煤主要以共价键交联的大分子结构为主,非共价键缔合的小分子含量较低,并以脂肪结构为主,含一定量的羰基以及少量的羟基和芳香结构。原煤和热溶残煤氧化水溶性产物中α,ω-二羧基烷酸含量较高,同时还发现,相当含量的芳香酸及三元羧酸存在,其中,α,ω-二羧基烷酸主要以丙二酸和丁二酸为主;原煤中可溶小分子易被氧化并生成较复杂的产物。与原煤相比,热溶残煤结构更为规整,氧化主要以共价键交联的大分子结构的氧化解聚为主,氧解率较低,水溶性氧解产物也较简单,种类较少,据此推测先锋褐煤的桥键主要以为-CH₂-和-CH₂-CH₂-为主。     

超临界二氧化碳中聚氨酯吸附小分子的影响因素

研究了超临界CO2 中降压时间以及小分子的溶度参数、亲电性和芳香性等因素对聚氨酯吸附小分子的影响,考察了小分子比蒸发速率对小分子在聚氨酯中解吸的影响.结果表明聚氨酯易于吸附亲电性试剂和多数芳香族小分子.通常比蒸发速率大的小分子在聚氨酯中解吸也快     

FT-IR和SEM用于煤阶对煤催化加氢气化影响的研究

基于加压固定床反应器研究了不同煤阶的煤催化加氢气化效果,对比了煤阶对催化剂添加量、甲烷释放速率以及产品气组成的影响。原煤及气化残渣采用FT-IR和SEM进行表征分析。研究结果表明,不添加催化剂情况下,随着煤阶的升高原煤气化反应性降低,低阶煤的甲烷释放分为两个阶段;加入催化剂之后,3种煤中以神府烟煤的反应性最好,遵义无烟煤和云南褐煤反应性较差。SEM和FT-IR表征结果表明,高阶煤颗粒表面更加光滑、煤结构致密,而煤中的脂肪族结构以及芳香结构振动峰强度随煤阶的降低而升高,催化剂的加入使得脂肪结构吸收峰明显加强。这些差异导致不同煤样催化加氢气化反应活性不同。     

超临界二氧化碳中聚氨酯吸附小分子的影响因素

研究了超临界ＣＯ２中降压时间以及小分子的溶度参数、亲电性和芳香性等因素对聚氨酯吸附小分子的影响,考察了小分子比蒸发速率对小分子在聚氨酯中解吸的影响。结果表明聚氨酯易于吸附亲电性试剂和多数芳香剂族小分子,通常比蒸发速率大的小分子在聚氨酯中解吸也快。     

Effects of organic micromolecules in coal on its wettability

Two types of bituminous coal were extracted with tetrahydrofuran solvent using microwave-assisted method at 50°C and atmospheric pressure. Pore structure parameters and wettability of raw coals and their residues were separately tested with nitrogen adsorption and capillary penetration method. Fourier transform infrared spectrometer was employed for analysis of surface functional groups of raw coals and their residues. Results showed remarkably degraded wettability of coal, especially gas coal, after extraction, whereas wetting height of raw coal reached more than twice that of residual coal within the same wetting time. Given the different storage characteristics of organic micromolecules in coal, pore volume of coal increased after extraction, and solvent extraction exerted different effects on pores. Pores of gas coal expanded with reduced specific surface area and improvement in hydrophobicity. Pores of coking coal increased with increasing specific surface area and degrading hydrophobicity. Organic micromolecules in coal and several side-chain groups in macromolecular skeleton structure were dissolved, reducing contents of functional groups in coal, decreasing quantities of groups, such as methyl and carbonyl, on coal surface, and modifying microcosmic surface characteristics of coal and improving hydrophobicity. Through comprehensive analysis, pore structure, and microcosmic surface characteristics of coal jointly determined its wettability.     

几种烟煤及其热处理后的溶胀性能研究

研究了四种不同变质程度烟煤及其二硫化碳/N-甲基-2-吡咯烷酮（CS2/NMP）混合溶剂(1∶1,vol)的抽提物在不同溶剂中的溶胀性能，同时考察了四种煤样不同温度热处理后其溶胀性能的变化。结果表明，煤的溶胀率随煤化度增加而有所降低;变质程度较低的烟煤在极性溶剂中的溶胀率大于非极性溶剂，随着煤化度的增加，两者溶胀度差距减小;四种烟煤经混合溶剂抽提后，其抽余煤的交联密度降低，溶胀率增加。四种煤样150℃热处理后在CS2中的溶胀率均有所增加，表明热处理可以降低煤的交联密度。随着热处理温度提高至240℃，除气煤外，其余三种煤样在NMP和CS2中溶胀率均进一步增大，说明其交联密度进一步降低。这一结果与热处理煤样在混合溶剂中抽提率的变化趋势一致，如240℃热处理后瘦煤的抽提率由原煤的6.9%提高到17.3%。红外光谱研究表明，经过适当温度的热处理，可以脱除煤分子中的羰基和羟基等含氧官能团，破坏煤结构中的氢键，从而降低煤的交联密度，提高煤的溶胀率及其在混合溶剂中的抽提率。     

煤的水热处理对其缔合结构的影响

对四种不同变质程度的烟煤进行了热处理和水热处理，采用二硫化碳N甲基吡咯烷酮（CS2 NMP,1∶1 volume ratio）混合溶剂在室温下对原煤及处理后的煤进行了抽提。结果发现，适当条件的热处理和水热处理均可以提高其在混合溶剂中抽提率，水热处理较热处理更能有效增加煤的抽提率。红外光谱分析表明，水热处理的煤样在波数为3410cm－1左右的吸收峰变小，由于水热解处理后氧的脱除而使—OH减少，使得由羟基形成的H键被削弱，因而抽提率增加。水热处理具有脱除矿物质的作用，对高变质程度的煤还可以脱除原煤中的π阳离子缔合，从而可以明显提高其抽提率。此外，对煤的水热解机理进行了探讨。     

Sorption of methane and CO2 for enhanced coalbed methane recovery and carbon dioxide sequestration

Sequestration of CO2 in deep and unmineable coal seams is one of the attractive alternatives to reduce its atmospheric concentration. Injection of CO2 in coal seams may help in enhancing the recovery of coalbed methane. An experimental study has been carried out using coal samples from three different coal seams, to evaluate the enhanced gas recovery and sequestration potential of these coals. The coals were first saturated with methane and then by depressurization some of the adsorbed methane was desorbed. After partial desorption, CO2 was injected into the coals and subsequently they were depressurized again. Desorption of methane after the injections was studied, to investigate the ability of CO2 to displace and enhance the recovery of methane from the coals. The coals exhibited varying behavior of adsorption of CO2 and release of methane. For one coal, the release of methane was enhanced by injection of CO2, suggesting preferential adsorption of CO2 and desorption of methane. For the other two coals, CO2 injection did not produce incremental methane initially, as there was initial resistance to methane release. However with continued CO2 injection, most of the remaining methane was produced. The study suggested that preferential sorption behavior of coal and enhanced gas recovery pattern could not be generalized for all coals.     

Sorption of methane and CO2 for enhanced coalbed methane recovery and carbon dioxide seauestration

Sequestration of CO2 in deep and unmineable coal seams is one of the attractive alternatives to reduce its atmospheric concentration. Injection of CO2 in coal seams may help in enhancing the recovery of coalbed methane. An experimental study has been carried out using coal samples from three different coal seams, to evaluate the enhanced gas recovery and sequestration potential of these coals. The coals were first saturated with methane and then by depressurization some of the adsorbed methane was desorbed. After partial desorption, CO2 was injected into the coals and subsequently they were depressurized again. Desorption of methane after the injections was studied, to investigate the ability of CO2 to displace and enhance the recovery of methane from the coals. The coals exhibited varying behavior of adsorption of CO2 and release of methane. For one coal, the release of methane was enhanced by injection of CO2, suggesting preferential adsorption of CO2 and desorption of methane. For the other two coals, CO2 injection did not produce incremental methane initially, as there was initial resistance to methane release. However with continued CO2 injection, most of the remaining methane was produced. The study suggested that preferential sorption behavior of coal and enhanced gas recovery pattern could not be generalized for all coals.     

水热处理对神华煤质的影响

结合水热处理煤的元素、灰分、挥发分分析以及IR光谱研究，讨论了水热处理对神华煤溶胀、抽提及液化性能的影响。结果表明，较高温度下水热处理存在明显的加氢作用，H/C摩尔比高于原煤；水热处理具有脱挥发分和脱灰作用，水热处理温度升高挥发分降低，灰分增加；水热处理的气态产物主要是CO2，250℃以上产生CO和CH4，其中CO2产率不受水热处理温度影响，CO和CH4产率则随水热处理温度升高而增加；水热处理降低了神华煤的溶胀性能，CS2/NMP混合溶剂抽提减小了抽余物在NMP溶剂中的溶胀度；适当温度水热处理能够提高CS2/NMP抽提率，但是索氏抽提性能有所降低；250℃~300℃水处理能够提高液化转化率，但是油气收率低于原煤，前沥青烯收率显著高于原煤。IR光谱分析表明,水热处理改变了煤分子中氢键等非共价键作用，其中较高温度水热处理将导致醚键、酯键等弱共价键水解和芳环侧链的断裂。     

溶剂萃取预处理对低阶煤大分子结构的影响

为了研究溶剂预处理对低阶煤的固有大分子结构的影响,本研究对锡林郭勒褐煤（XLL）和神府次烟煤（SFC）分别进行了四氢呋喃（THF）索氏抽提、二硫化碳/N-甲基-2-吡咯烷酮（CS₂/NMP）混合溶剂抽提及热溶处理,并对所得抽余煤进行了傅里叶红外漫反射光谱分析（DRIFT）、热重分析（TGA）、压汞法分析（MI）和溶胀度测定。结果表明,溶剂抽提导致煤大分子结构重排和再缔合。其中,THF索式抽提和CS₂/NMP混合溶剂抽提可以改变非共价键交联作用,特别是氢键作用分布,从而不同程度地松弛煤大分子结构。然而,高温溶剂热溶处理主要促进了煤大分子的共价键交联,尤其是对锡林郭勒褐煤（XLL）。所有抽取煤的溶胀都受Fickian扩散控制,且所有抽取煤的溶胀活化能都低于原煤。     

溶剂萃取对烟煤孔隙结构和粒度的影响

用二硫化碳-N-甲基-2-吡咯烷酮（CS2-NMP）(1∶1, V/V) 混合溶剂、丙酮和吡啶对南桐烟煤逐级萃取，得到各级残余物。通过比表面积及孔快速测试仪和扫描电镜，对煤及各萃取残余物的氮气吸附行为、粒度进行测试，考察了溶剂萃取对煤的BET比表面积与BJH孔容、孔面积随孔径分布规律以及粒度的影响。结果表明通过“溶解”小分子物质，溶剂萃取能够有效地改善煤的吸附性、比表面积和孔隙结构，降低其粒度，但不能破坏其基本结构单元，在本质上仍属于物理作用。根据最可几孔径计算出南桐烟煤胶态分子团结构模型中基本结构单元的粒径在3.5 nm左右，证实了煤分子胶态团结构模型的假设。