煤的可溶组分对粘结性的影响

在室温下用二硫化碳-N-甲基-2-吡咯烷酮(CS2-NMP)混合溶剂对煤样进行了抽提实验,考察了煤的可溶组分对抽提率和粘结性的影响,探讨了抽提率与粘结性之间的关系。结果表明,煤的抽提率对粘结性有较大的影响。     

煤的CS2/NMP溶剂抽提

综述了溶剂抽提的发展和现状,介绍了V(CS2)∶V(NMP)=1∶1的混合溶剂,对影响该混合溶剂抽提率的因素、抽提机理和相关理论计算研究进行了讨论,展望了该领域的研究方向。     

微波辅助抽提煤的实验研究

在微波辅助下,以四氢呋喃、乙醇和乙酸为溶剂抽提神府煤,考察了抽提温度、抽提时间、溶剂用量及煤粒度对抽提率的影响;同时探讨了上述三种溶剂对不同变质程度的攀枝花煤、铜川煤、神府煤、华亭煤和依泰煤在微波辅助下的抽提效果.结果表明,抽提率在一定的抽提温度、时间、溶剂用量及煤粒度下均有最佳值;变质程度相似的煤在相同抽提条件下抽提率不同.运用红外光谱现代分析技术,对神府脱灰煤和其抽提残煤的结构特征进行了对比分析,结果表明,抽提并没有破坏煤的大分子结构;利用GC/MS测定了铜川煤的乙醇微波辅助抽提物的组成.     

煤溶胀动力学与热力学的研究

以煤溶胀机理、氢键等为基础,从热力学和动力学方面综述了煤溶胀的本质,讨论了溶剂性质、氧化、温度、煤粉粒度及热处理对溶胀动力学的影响。结果表明：溶胀过程中,表观活化能和速率常数不仅与溶剂分子的空间属性有关,还受溶剂分子形状的影响;混合溶剂的协同效应极大地提升了溶胀速率,增大了表观活化能;抽提煤的干燥条件不同及煤经过氧化后,溶胀机理均会发生明显改变。最后详细介绍了煤溶胀技术对煤分子结构的影响及在煤液化方面的应用。     

溶剂类型对煤微波辅助抽提率及组成的影响

以神府煤和攀枝花煤为对象进行煤微波辅助抽提研究,所用溶剂有甲醇、乙醇、丙酮、乙酸、四氢呋喃、乙二胺和DMF等.结果表明,前四种溶剂对攀枝花煤的抽提率较高,后三种溶剂对神府煤的抽提率较高,其中乙二胺对神府煤的抽提率可达70.76%.抽提残煤的元素分析、官能团测定及FT-IR分析表明,各残煤H/C和O/C比略有降低而N/C明显升高;含氧官能团含量较脱灰煤有所增加,总酸性基及羟基含量提高;另外,利用GC/MS检测脱灰神府煤四氢呋喃抽提物,正己烷可溶物含较多的脂肪烷烃,甲苯可溶物中则含各种芳香族化合物,四氢呋喃可溶物中只检测到一种含氧杂原子化合物.     

煤的溶剂抽提规律及其产物性能的研究进展

阐述了温和条件下煤的溶剂抽提机理，煤分子间作用力，溶剂种类对抽提率的影响。抽出物的洁净性能，抽余物的吸附性能，抽提产物表面的物化以及表面活性剂对煤的亲水/疏水性，ζ电位和氮气吸附性能的影响。结果表明，对于高阶煤，加入中性活性剂TericG12A8可以有效降低其ζ电位，增大其氮气吸附量和疏水性。     

煤的溶剂抽提研究进展

介绍了影响煤溶剂抽提的因素及提高煤溶剂抽提效率的一些主要的辅助方法(超声辐照,微波辐射,水热处理),并通过对比多种煤溶剂抽提的实验室研究进展和溶剂抽提技术在工业化应用的情况,提出了今后关于煤溶剂抽提的发展方向。     

CS2—NMP混合溶剂中煤萃取率的研究

在温和条件、室温、常压下用ＣＳ２－ＮＭＰ混合溶剂对徐州、淮北、龙口、枣庄煤各种宏观煤岩组分进行抽提,探讨了煤阶、煤冉组分与萃取率的关系。     

煤的溶剂萃取研究进展（I）有机溶剂及其萃取机理

讨论了煤的溶剂萃取研究现状，主要介绍单一溶剂，如四氢呋喃（THF）、环已酮（CHO）及吡啶（Py)等；混合溶剂，主要是N－甲基吡咯烷酮（NMP）混合溶剂，如CS2／NMP和CHO／NMP等的萃取性能，介绍添加剂、煤岩组成以及辅助手段等对煤溶剂萃取的影响，辅助手段主要是超声辐射、电磁辐射以及化学处理等，它们或多或少改变萃取过程，一般可使萃取率提高，同时对单一溶剂萃取机理、混合溶剂萃取机理、添加剂增溶机理以及辅助手段增溶机理等进行了讨论。研究证明，煤的有机溶剂萃取受许多因素影响，其中改变溶剂或加入一定量添加剂可以在一定程度上改变煤的溶剂萃取性能，实验条件也是一个重要的影响因素，但煤本身的问题，诸如煤的结构、煤的组成、实质程度以及煤岩组成等也会对煤的溶剂萃取性能产生重要影响。     

煤的溶剂萃取研究进展(Ⅰ) 有机溶剂及其萃取机理

讨论了煤的溶剂萃取研究现状,主要介绍单一溶剂,如四氢呋喃(THF)、环己酮(CHO)及吡啶(Py)等;混合溶剂,主要是N-甲基吡咯烷酮(NMP)混合溶剂,如CS2/NMP和CHO/NMP等的萃取性能.介绍添加剂、煤岩组成以及辅助手段等对煤溶剂萃取的影响,辅助手段主要是超声辐射、电磁辐射以及化学处理等,它们或多或少改变萃取过程,一般可使萃取率提高.同时对单一溶剂萃取机理、混合溶剂萃取机理、添加剂增溶机理以及辅助手段增溶机理等进行了讨论.研究证明,煤的有机溶剂萃取受许多因素影响,其中改变溶剂或加入一定量添加剂可以在一定程度上改变煤的溶剂萃取性能,实验条件也是一个重要的影响因素,但煤本身的问题,诸如煤的结构、煤的组成、变质程度以及煤岩组成等也会对煤的溶剂萃取性能产生重要影响.     

Extraction of coals with CS2-N-methyl-2-pyrrolidinone mixed solvent at room temperature Effect of coal rank and synergism of the mixed solvent

Coals (from lignite to anthracite) were extracted at room temperature with CS₂-N-methyl-2-pyrrolidinone (MP) mixed solvent (1:1 by volume), which was found to be a very efficient solvent for the extraction of bituminous coals in a previous study. High yields of 30–66% (daf) were obtained for 29 of the 49 bituminous coals (C%76.9–90.6% daf) examined. The anthracite, subbituminous coals and lignites did not give high yields. The results of the characterization of the raw coals, extracts and residues suggest that reactions between the coals and the solvents do not occur to a significant extent during the extraction. The synergistic effect, i.e. the large increase in yield and rate for the mixed solvent compared with those for CS₂ and MP alone has been explained by increasing solubility and diffusibility of the extracts and increasing swelling of the coals, in the mixed solvent. The mixed solvents of CS₂ with quinoline, pyridine and THF gave lower extraction yields than the CS₂-MP mixed solvent.     

Reactivity of cycloalkanes during the solvent extraction of coal

The reactivity of cycloalkanes, either alone or as part of a solvent mixture, during the solvent extraction of coal at 430 °C has been studied. When used with polyaromatic compounds (? 3 rings) as solvents, cycloalkanes participate in hydrogen donation reactions giving rise to high extraction yields of the coal.     

Effect of coal extracted with NMP on its aggregation

Tow-step extraction of Upper Freeport (UF) coal, i.e. exhaustive extraction with N-methyl-2-pyrrolidinone (NMP) solvent and subsequent extraction with the CS2/NMP mixed solvent (1:1 by volume) with or without additive was compared with the direct extraction of UF coal with the CS2/NMP mixed solvent (1:1 by volume) with or without additive. It was found that there is almost no difference of extraction yields between the two-step extraction and direct extraction with or without additive. The result show that NMP can only give external extraction to extract the outside fractions of coal particles, and this will not cause the new aggregation formed in the coal molecules. The interactions between coal molecule and additive are responsible for the extraction yield enhancement by additive.     

Effect of coal soluble constituents on caking property of coal

Three cokemaking bituminous coals were extracted by the CS₂/NMP mixed solvents with different content of NMP, and the effect of the amount and the component of coal soluble constituents on the caking property of the extracted residues of coals were investigated in this study. The CS₂/NMP mixed solvent (1:1 by volume) was found to give the maximal extraction yields for the three coals, and the fat coal gave the highest extraction yield of 78.6% (daf) corresponding to its highest caking index of 101. It was found that for coking coal, when the extraction yield got to the maximum of 25.3% in the 1:1 by volume of CS₂/NMP mixed solvent, the residue extracted still had caking property with the caking index of 19. This means parts of the caking constituents of coal are un-extractible because of covalent bonding or strong associative cross-links. The soluble components extracted by the CS₂/NMP mixed solvent and their effects on the caking indexes of the residues at a similar extraction yield quite differed depending on the NMP content in the mixed solvent. The coal solubles extracted by the CS₂/NMP mixed solvent with NMP less than 50% contained less light constituents with less of oxygen groups. This may lead to the decrease in the caking indexes for the residues obtained at the similar extraction yields compared to those of the CS₂/NMP mixed solvent with NMP more than 50%.     

Filtration in coal liquefaction: 1. Influence of coal type

Commercial solvent extraction systems for coal must be able to process coals with various properties. In this study the influence of coal type upon the extraction yield of coal and the filtration of extraction products has been investigated. All the coals used gave high extraction yields in hydrogenated solvent but resultant products exhibited considerable differences in rates of filtration. This variation in filtration rates is dependent upon particle size, concentration and composition of the residual solids. No simple relation was found to relate coal type with filtration rate.     

Solvent effects in coal desulphurization by chlorinolysis near ambient temperature

The effects of solvent, temperature and reaction time on the desulphurization efficiency of the low-temperature chlorinolysis process were studied. Certain trends in sulphur reduction, chlorine uptake and extraction yield for coals undergoing slurry-phase chlorine treatment were established. Methanol-based solvent systems were found to display remarkable capabilities in coal chlorinolysis both in terms of selective sulphur extraction and high yields of coal extracts.     

用CS2—NMP混合溶剂抽提法制备洁净煤

室温常压下，用ＣＳ２－Ｎ一甲基－２－吡咯烷酮（ＣＳ２－ＮＭＰ）混合溶剂（１：１，Ｖ／Ｖ）萃取徐州庞庄煤，得到萃取物．经ＸＲＤ和ＴＥＭ分析，表明萃取物基本无灰，且多为在８０ｎｍ～２４０ｎｍ之间的细小碎片，是一种超纯超微洁净煤．