煤的溶剂萃取研究进展

综述了近年来溶剂萃取煤的研究进展 ,讨论了影响萃取率的主要因素 ,包括溶剂、煤阶、煤岩组分及辅助手段等以及单一及混合溶剂的萃取机理。指出从分子水平上对煤进行分离进而分析是确定煤的化学结构的关键 ,而可溶化是从分子水平上分离煤的必要条件。溶剂分级萃取是一种行之有效的萃取方法 ,并提出了煤的溶剂萃取技术的若干研究方向     

Solvolytic extraction of coal through acylation and amidomethylation

Carboxylic acids, acid anhydrides and N-hydroxy methylamides were used to acylate Assam coal under Friedel—Crafts reaction conditions. This reaction resulted in the enhancement of the extractability of coal in benzene—methanol (7:3 vol./vol.) and quinoline after acylation with carboxylic acids and acid anhydrides. The effect of catalyst (AlCl₃) concentration on reaction was also investigated. l.r. spectra of reaction products indicated the introduction of acyl groups in the coal structure. Phthalimidomethylation could render about 50% coal extractable in quinoline.     

Mechanism of swelling and extraction and coal structure

An attempt is made to develop a comprehensive model of coal structure based on results of various experiments involving extraction and swelling of a coal by solvents. These are described in terms of electron-donor and electron-acceptor characteristics, of mass spectrometric analysis of coal extracts, of pulse ¹H n.m.r. measurements of mobilities of coal components, porosity measurements. The theory of coal swelling cannot be adapted from the theory of polymer swelling.     

Influence of pre-swelling on extraction of coal

Swelling of hvB coal by vapour of the solvents pyridine, tetrahedrofuran, dimethylformamide and methanol was carried out. Vapour-saturated coals were extracted using selected solvents and extract yields for swollen and fresh coals were compared. It is found that some solvents can block pathways to some, but not all, sites that were accessible to other solvents when they were interacting singly with fresh coal.     

Supercritical solvents. Carbon dioxide extraction of retained pyridine from pyridine extracts of coal

Pyridine extracts of coal are excellent models for studies of coal structure and reactions, but the pyridine that is retained is undesirable. A method is described, using supercritical carbon dioxide, for the removal of retained pyridine from pyridine extracts of Illinois No. 6 and Western Kentucky No. 9 coals.     

煤的溶剂热萃取研究进展

综述了近年来在煤的溶剂热萃取（不小于300℃）的研究进展。讨论了主要影响因素包括极性溶剂、酸处理、萃取时间等对热萃取率的影响。结论表明：酸处理、使用强极性溶剂有利于提高煤的热萃取产率;时间和温度是热萃取的两个重要参数,在不同程度上影响着煤的热萃取率;萃取物活性很高,并且基本无灰,是煤直接液化的极好的原料也可以作为内燃机燃料。     

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.     

Supercritical gas extraction of coal with hydrogen-donor solvents

An investigation of the effect of a hydrogen-donor component in the solvent used for supercritical gas extraction was undertaken. Extraction of three Australian coals with toluene, with decalin and with these solvents containing small amounts of tetralin was investigated. There was a significant improvement in conversion by addition of 5% tetralin to the solvent. Other hydrogen donors were also effective. The improvement in conversion was shown to be due to hydrogen donation rather than to a change in the physical properties of the solvent. The increase in conversion was greater for a brown coal than for a bituminous coal of the same hydrogen to carbon atomic ratio. The pre-asphaltene content of the extract increased with conversion.     

煤的超临界流体抽提研究进展

超临界流体抽提技术是一项新型、绿色、环保的技术,超临界流体抽提技术应用于煤的目的分为超临界条件下气化制氢,超临界条件下脱除杂质和超临界条件下煤的液化3个方面,综述了超临界流体抽提技术应用于煤的研究进展,并着重论述了该技术应用于煤液化的研究进展,指出了今后的研究方向。     

Removal of pyridine and quinoline from coal and coal extracts

Techniques for the removal of pyridine and quinoline from coal, coal extracts and coal residues have been developed. The combination of repeated vacuum drying at 1.3 kPa and 90–110 °C, with repeated washing using methanol was found to be sufficient to remove the pyridine and quinoline from the coal extracts and residues.     

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。     

煤化工有机废渣萃取处理的研究进展

煤化工有机废渣是煤化工生产过程中产生的有毒有害的有机固体废弃物,有强烈的刺激性气味,对人类及环境都有巨大的危害,一般归属于危险废物。为了更加有效地处理这些废渣,在分析国内外煤化工有机废渣处理技术的基础上,对煤化工有机废渣的各种萃取处理技术——普通溶剂萃取分离法、超临界萃取分离法、溶剂油萃取分离法、离子液体溶剂萃取分离法、切换溶剂萃取法等进行了详细介绍,并比较了各方法的优缺点,对比分析了各类萃取溶剂、萃取工艺,以期为未来煤化工有机废渣的处理提供参考。     

煤焦油超临界流体提取的研究进展

超临界流体抽提技术是一项新型、绿色、环保的技术,超临界流体抽提技术应用于煤焦油研究的主要目的分为超临界条件下提取其中成分,使煤焦油轻质化,本文介绍了超临界流体抽提技术应用于煤焦油的研究进展,指出了今后的研究方向.     

Rapid extraction of products from coal hydrogenation reactions using an ultrasonic bath

Extraction of products into dichloromethane solution from reactions of Victorian brown coals with hydrogen in tetralin can be achieved in 2 min by immersing the extraction mixture in an ultrasonic bath at ambient temperature. The same levels of extraction using the Soxhlet technique can only be achieved by prolonged periods of extraction during which the coal extracts are heated at the reflux temperature of the solvent.     

Fractionation of brown coal by sequential high temperature solvent extraction

Separation of brown coal into fractions having rather uniform structure is believed to be one of the promising pretreatment methods for effective utilization of brown coal. The authors have recently presented a new coal fractionation method that can separate a bituminous coal into several fractions having different molecular weight compounds without decomposing the coal. The method extracts coal using a flowing stream of non-polar solvent such as tetralin or 1-methylnaphthalene by increasing the extraction temperature stepwise up to 350 °C. In this study the fractionation method was applied to fractionate a brown coal. Water was used as an extracting solvent in addition to tetralin and 1-methylnaphthalene by intending to utilize inherent water of brown coal as the extraction solvent. An Australian brown coal was successfully fractionated into six fractions by any solvents, but the properties of the fractions were significantly different depending on the extraction solvent. This is because tetralin, 1-methylnaphthalene, and water interacted significantly with the brown coal in different ways even at less than 350 °C. The difference in chemical structure and thermal properties of the fractions were examined in detail through ultimate analysis, ¹³C NMR, molecular weight distribution, and thermogravimetric and thermomechanical analyses.     

低阶煤有机溶剂萃取的研究进展

鉴于煤有机溶剂萃取的迅速发展,以低温和高温热萃取作对比,对相应的萃取机理、影响因素及萃取物的应用等进行分析。结果表明:萃取温度在200℃以下的多为低温物理萃取,萃取率一般较低,所得萃取物多用于研究煤的分子结构;而温度在300~400℃的萃取多为高温溶剂萃取,所得萃取率较高,萃取过程中会伴随化学键的断裂及相应化学反应的发生,所得萃取物多用在研究配煤炼焦、劣质煤的气化液化、新型煤基材料等领域。     

Carbon disulphide-pyridine mixture,a new efficient extraction solvent for coal

It has been found that carbon disulphide-pyridine mixture (1:1 vol.) is an efficient solvent for the extraction of bituminous coals at room temperature. Dimethylformamide, hexamethyl phosphoric triamide and dimethyl sulphoxide also give high extraction yields in the mixture with carbon disulphide.     

不同煤阶煤的吡啶抽提FTIR谱研究

在相同的实验条件下,对四种不同煤阶的煤用搅拌抽提法进行吡啶抽提,并利用傅立叶变换红外光谱(FTIR)对原煤及残煤进行了定量测试,讨论了不同抽提率产生的原因,研究了吡啶抽提前后官能团含量的变化。分析表明,溶剂吡啶主要作用于煤基本结构单元芳核的侧链和桥键。     

肥煤的热抽提及其抽提物的性能研究

主要考察了肥煤在不同温度及不同溶剂下的热抽提性能,并对热抽提物性质进行了分析。实验结果表明,提高热抽提温度,肥煤热抽提率增大,并在其软化点附近达到最高值,而后随温度的升高而降低;增大溶剂极性,肥煤热抽提率也显著升高。热重和红外分析显示了热抽提物结构的变化,其基本无灰的特点有望成为煤洁净利用的突破口。     

煤直接液化残渣萃取技术现状及发展趋势

为实现煤液化残渣的高效利用,分析了煤直接液化残渣特性,论述了煤直接液化残渣经萃取提取高附加值有机物,如沥青和重油的研究现状,阐述了煤直接液化残渣萃取溶剂的种类、萃取工艺条件的选择以及萃取物的性能和用途等,提出了煤直接液化残渣萃取技术的发展趋势。采用合适的萃取剂和萃取条件可从液化残渣中萃取出制备沥青的原料和可作为液化循环溶剂使用的油分,萃取剂可包括各种已知的常规萃取溶剂及其混合物、离子液复合萃取剂和各种煤液化或石化馏分油,萃取出的沥青类物质可制备高级碳材料,特别是碳纤维材料,萃取出的油分可用作煤液化循环溶剂或燃料。提出未来应开发针对煤直接液化残渣的高效、低廉的新型有机溶剂萃取剂,研究多步或多级萃取工艺,实现萃取工艺的进一步优化和简化,形成萃取工艺和其他工艺,如加氢裂化工艺和加氢精制工艺结合的复合工艺。