神华煤在有机溶剂中溶胀动力学的研究

研究了不同温度( 4 0℃～1 2 0℃)下神华煤在有机溶剂N,N-二甲基甲酰胺、四氢萘和循环油中的溶胀动力学.结果表明:随温度升高,神华煤在有机溶剂中的溶胀速率在增大,但在极性溶剂N,N-二甲基甲酰胺中的溶胀速率远大于在非极性溶剂四氢萘中的溶胀速率;神华煤的溶胀行为符合一级反应动力学方程;神华煤在三种溶剂中的活化能均小于1 0 k J/mol,表明在溶胀过程中,其速度由溶剂分子在煤中的扩散所控制.     

溶剂与溶胀促进剂对神华煤溶胀行为的影响

采用体积法研究了甲苯、四氢萘、甲醇、二甲亚砜、N,N-二甲基甲酰胺(DMF)和乙醇胺(MEA)5种纯溶剂及1∶1的MEA-DMF混合溶剂对神华烟煤的溶胀行为,考察了Fe(NO3)3、Fe2(SO4)3和FeSO4添加量为0.5%(以铁占煤质量计)作为溶胀促进剂的性能。结果表明:MEA-DMF混合溶剂的溶胀效果优于5种单一溶剂。铁盐Fe(NO3)3明显促进煤溶胀,在80℃,24h和剂煤比5∶1条件下MEA-DMF混合溶剂与Fe(NO3)3协同可使溶胀率超过3.0。对溶胀处理后的神华煤FT-IR表明DMF、DMF-MEA溶胀处理以及与Fe(NO3)3协同溶胀处理后明显削弱了煤羟基氢键间的缔合作用,其中,经DMF-MEA与Fe(NO3)3协同溶胀处理的这一变化最为明显。     

依兰煤在液化溶剂中的溶胀动力学研究

笔者以依兰煤为原料,研究了依兰煤在室温至2000℃范围内在液化起始溶剂和循环溶剂中的溶胀行为,并确定了依兰煤在试验条件下的溶胀动力学参数。试验结果表明：依兰煤在液化起始溶剂和循环溶剂中的溶胀度随溶胀温度的增加和溶胀时间的延长而增大;依兰煤在这2种溶剂中的溶胀都是受Case-Ⅰ扩散控制为主的过程,其溶胀活化能分别为4．18和4．22kJ·mol^-1。     

煤溶胀前后溶解度参数变化研究

选择6种性质不同的溶剂作为溶胀剂,对烟煤进行了溶胀预处理。对溶胀前后煤样进行了形貌分析、红外分析及溶解度参数测定,并考察了直接加氢液化效果。结果表明,溶剂溶胀预处理未破坏煤大分子结构,而煤的微观形貌变得疏松。所选6种溶剂中,N,N-二甲基甲酰胺(DMF)与煤二者之间的溶解度参数差值最小,DMF对煤溶胀效果也最好,溶胀度达1.71。同时,6种溶胀煤中,经DMF溶胀煤样(C_(DMF))的溶解度参数值最低,直接液化性能最好。相比于原煤(C_R),C_(DMF)的溶解度参数降低了2.73%,气产率降低了89.71%,液产率和转化率分别提高了27.48%和5.35%。     

新疆伊犁煤溶胀行为的研究

本文研究了新疆伊犁煤在甲苯、甲醇、四氢呋喃（THF）、N-甲基吡咯烷酮（NMP）和陆梁原油不同溶剂下的溶胀行为,考察了煤预处理温度、不同溶剂、煤／溶剂体积比、溶胀时间对煤溶胀度的影响。结果表明：经过110℃真空干燥预处理煤样的溶胀度大于经过50℃真空干燥预处理煤样的溶胀度;相同条件下,NMP的溶胀度最大;煤／溶剂体积比越大,煤的溶胀度越小;溶胀24h煤样的溶胀度同溶胀60h煤样的溶胀度变化不大。     

煤溶胀影响因素及溶胀技术的应用

以煤溶胀机理、溶胀动力学等为基础,综述了溶剂性质、煤阶、氧化、温度、预处理、溶胀时间、水分、煤粉粒度等对煤溶胀的影响。结果发现:溶剂的供电子数目(EDN)、溶剂碱性、溶剂类型对煤的溶胀有不同的影响。煤阶对煤的溶胀影响较大,表现在随着C的增多,溶胀度也在增大,但当C含量大于85%时,溶胀度急剧降低。氧化煤易于溶胀。升高温度和预处理均有利于煤的溶胀。煤粉粒度越小溶胀度越好。脱除煤中的矿物质后有利于提高煤的溶胀度,但增加幅度不大。最后详细介绍了煤溶胀技术在研究煤分子结构、煤热解、煤液化方面的应用。     

高温高压下煤在溶剂中溶胀特性及动力学分析

根据溶胀测量原理,结合位移传感器,设计了一种可以在高温高压条件下测量煤样在溶剂中溶胀的装置.测量获得了不同颗粒粒度B3煤样在神华循环油中、N_2气氛下溶胀比随温度的变化曲线,同时考察了初始压力、气氛和煤阶对煤样高温溶胀特性的影响,并采用非等温溶胀动力学方程对溶胀数据进行拟合分析.结果表明,不同颗粒粒度B3煤样的溶胀比随温度的升高而增大,在300℃时达到最大溶胀比,随着温度的进一步升高,溶胀比减小,煤层高度开始降低.增大初始压力和H_2气氛下有利于煤样的溶胀.煤样在四氢萘中的溶胀比较在循环油中大.非等温溶胀动力学拟合分析表明,煤在溶剂中溶胀遵循简单级数反应机理函数,活化能在20kJ/mol~60kJ/mol之间.     

几种煤的溶胀动力学研究

测定了不同溶胀时间下胜利煤、H煤和神华煤在九江循环溶剂中的的溶胀度,研究了这三种煤在常压下溶胀动力学行为,胜利煤、神华煤和H煤的平衡溶胀度(溶胀4 h)分别为1.068,1.054和1.162,胜利煤和神华煤约35 min达到溶胀平衡,H煤约20 min即达到溶胀平衡,开发了一种新的溶胀动力学模型--吸附溶胀动力学模型,按二级动力学方程对煤粒的溶胀行为进行描述,并利用文献查得的Suuberg法动力学方程分析可知,胜利煤、H煤和神华煤在九江溶剂中的扩散主要是Case-Ⅱ扩散,经比较可知,吸附溶胀法较Suuberg法能更好地描述煤的溶胀行为.     

微波溶胀对五彩湾煤直接液化影响的研究

采用NMP/CS(2体积比1︰1)混合溶剂,在微波辐射下对五彩湾煤进行溶胀处理,并将原煤和微波溶胀煤样进行对比表征和加氢液化实验,考察了液化反应温度、反应气氛、溶胀剂对液化效果的影响。结果表明:微波溶胀后,煤样孔隙结构显著增加,结构发生变化。在液化条件是温度450℃、氢初压6.0 MPa、溶煤比1.75︰1和反应时间60 min,油产率和转化率分别是原煤55.02%和76.76%,微波溶胀煤74.03%和84.78%。     

鑫源煤在有机溶剂中的溶胀特性研究

对不同溶胀时间、不同溶剂、矿物质、预处理和金属无机盐等实验条件下鑫源低阶烟煤的溶胀行为和溶胀动力学进行了研究.结果表明,随着时间的延长,溶胀率逐渐增大,48 h溶胀基本达到平衡,溶胀特征是典型的slow-climbing-type溶胀;煤在混合溶剂中的溶胀率大于单一溶剂中的溶胀率,在极性溶剂中的溶胀率大于非极性溶剂中的溶胀率;脱除矿质元素后,煤溶胀率增大;溶胀、酸洗和碱洗使煤溶胀率增大,烘干使煤溶胀率减小;溶胀动力学表明,该煤的溶胀行为符合一级反应动力学方程,在THN和吡啶溶剂中的表观活化能均小于20 kJ/mol,这与煤中范德华力的破坏相对应,溶胀机制是由Case-Ⅱ扩散控制的.     

Effect of pre-swelling of coal on its solvent extraction and liquefaction properties

Effects of pre-swelling of coal on solvent extraction and liquefaction properties were studied with Shenhua coal. It was found that pre-swelling treatments of the coal in three solvents, i.e., toluene (TOL), N-methyl-2-pyrrolidinone (NMP) and tetralin (THN) increased its extraction yield and liquefaction conversion, and differed the liquefied product distributions. The pre-swollen coals after removing the swelling solvents showed increased conversion in liquefaction compared with that of the swollen coals in the presence of swelling solvents. It was also found that the yields of (oil + gas) in liquefaction of the pre-swollen coals with NMP and TOL dramatically decreased in the presence of swelling solvent. TG and FTIR analyses of the raw coal, the swollen coals and the liquefied products were carried out in order to investigate the mechanism governing the effects of pre-swelling treatment on coal extraction and liquefaction. The results showed that the swelling pre-treatment could disrupt some non-covalent interactions of the coal molecules, relax its network structure and loosened the coal structure. It would thus benefit diffusion of a hydrogen donor solvent into the coal structure during liquefaction, and also enhance the hydrogen donating ability of the hydrogen-rich species derived from the coal.     

低温煤焦油中正十二烷-甲苯-苯酚的相平衡及分离

低温煤焦油组分的分离对其充分利用具有重要的作用。分别以正十二烷、甲苯和苯酚为模型化合物,采用实验和Aspen Plus模拟两种方法得到了低温煤焦油中脂肪烃-芳烃-酚类三元体系的液液平衡关系,并模拟了N,N-二甲基甲酰胺（DMF）水溶液萃取分离该体系时的典型三元相图。结果表明,Aspen Plus采用UNIF-LL法模拟得到的三元相图与实验测定结果吻合较好。甲苯在正十二烷-甲苯-苯酚体系中作为共溶溶剂,促使三元体系成为均相。根据正十二烷、甲苯和苯酚在DMF中的溶解性差异,结合Hansen溶度参数理论,通过在DMF中添加不同含量的H₂O以调节萃取剂的极性,可使正十二烷和甲苯依次从均相体系中分离。通过对萃取温度、剂油比和萃取剂含水量进行优化,最终在303.15 K,剂油比为1.5时,以DMF对模型油进行单级萃取,可以得到纯度为93.2%的正十二烷;相分离后向萃取相中添加DMF量30%的H₂O,可分离出纯度为93.4%的甲苯。     

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。     

Evidence for the associated structure of bituminous coal

Previous studies have shown that coal swelling is not reversible and highly dependent on coal concentration in a solvent. This rules out the conventional coal structural model of a covalently cross-linked three-dimensional network. Many coal molecules may be physically associated by relatively strong intra- and intermolecular interactions. Coal swelling in selected solvents was examined for fractionated samples of two high volatile C bituminous coals to investigate the role of physical associations in coal structure. The dependence of coal concentration on swelling in tetrahydrofuran and toluene was similar for pyridine soluble and insoluble fractions. Solvent swelling of pyridine solubles was smaller than that of pyridine insolubles. Pyridine extract was mixed with iodine and further fractionated into pyridine soluble and insoluble fractions. The swelling ratio of the pyridine solubles was much smaller than that of the pyridine insolubles. The difference between swelling with toluene and with tetrahydrofuran was larger for pyridine insolubles than for pyridine solubles. All these results indicate that significant portions of coal molecules are not a three-dimensional network, but are physically associated.     

Microscopic observations of the swelling of a high-volatile bituminous coal in response to organic solvent

The swelling behaviour of individual coal macerals in response to solvents is thought to be important since it represents an early stage in the disintegration of the coal, which is, in turn, of fundamental importance to coal hydrogenation at elevated temperatures. Therefore, a detailed incident-light microscope study of solvent-treated, polished coal surfaces, involving a new edge-on mode of observation, was undertaken in order to observe the way in which solvents interact with the different coal macerals. This study was carried out on blocks of Bayswater Seam coal, using tetralin, pyridine, and 1:3 maleic anhydride-xylene solutions at temperatures near their respective boiling points. The degree of swelling of the polished coal surface depends on the nature of the organic solvent and the individual coal macerals. Vitrinite and, in some instances, low-reflectance semifusinite exhibit varying degrees of swelling in response to the solvent treatment; whereas exinite and the majority of the inertinite macerals appear to be unaffected by the solvents. Within the vitrinite group the lower-reflectance sub-macerals exhibit the greater degree of swelling. At temperatures of less than 200 °C the ability of the solvents to produce swelling in the coal decreases in the order pyridine → 1:3 maleic anhydride-xylene → tetralin.     

Effect of pre-swelling of coal at mild temperatures on its hydro-liquefaction properties

The effects of pre-swelling treatment of Shenhua coal at mild temperatures (less than 160 °C) on its hydro-liquefaction properties were determined in this paper. It was found that with the increase of pre-swelling temperature in tetralin (THN) up to 120 °C, the liquefaction conversions of swollen coals increased. However, when N-methyl-2-pyrrolidinone (NMP) was used as swelling solvent, the liquefaction conversion decreased with the increase of pre-swelling temperature. The liquefied product distributions were very much dependent on the pre-swelling pretreatment conditions, and the mechanism was discussed. Based on the results obtained, a new swelling-liquefaction combining technology (SLCT) was advanced, in which the liquefaction conversion and oil + gas yield were enhanced.     

溶胀处理煤对煤结构与煤基聚苯胺导电性影响

首次选用苯胺为溶剂对神府煤(SFC)进行溶胀处理,以研究其对煤结构与煤基聚苯胺导电性的影响,对其结构进行TG/DSC、FTIR和SEM分析,并通过溶胀SFC处理煤为聚合基体,在苯胺和引发剂条件下聚合为煤基聚苯胺,测定了其导电率。结果表明:苯胺溶胀处理破坏了煤中非共价键,降低了煤的交联缔合度,疏松了煤的孔结构,在此条件下的煤基聚苯胺的导电率均小于溶胀处理前原煤为聚合基体的煤基聚苯胺导电率,这与煤大分子网络结构受到一定程度破坏有关,这可为煤基聚苯胺的扩大化生产提供重要参考。