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     

煤溶剂萃取新技术研究进展

分析了煤溶剂萃取的研究现状,对比了微波溶剂萃取、超临界流体萃取和超声波萃取3种新技术在萃取过程中的优劣及萃取结果,对如何有效、经济、合理地利用煤的问题给予启示.基于当前煤化工的发展状况,对煤的溶剂萃取研究前景进行了展望.     

高效水煤浆制浆燃烧集成技术研制与应用

为促进煤炭的清洁高效利用,株洲市蓝宇热能科技研制有限公司依托子母炉层-悬浮燃烧水煤浆锅炉,集成膜分离、功率超声处理与高效机械离心分离等绿色低碳技术,构建了新型高效生物质水煤浆制浆燃烧系统。该系统由有机废液的高效预处理模块、污泥的高效预处理模块、生物质水煤浆制浆模块、生物质水煤浆燃烧模块和净化水生化处理模块5个模块组成。高效水煤浆制浆燃烧集成技术已有多项工程应用实例,结果证明:该技术能有效降低有害气体的排放,同时实现污泥、有机废液的能源、资源化利用。     

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.     

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。     

褐煤制浆和配煤制浆技术

基于中国煤炭资源状况及褐煤难成浆的特点,提出采用配煤制浆的方法来提高制浆浓度。分析了国内外褐煤和配煤制浆技术的研究现状,同时介绍了国内褐煤制浆技术的发展。研究发现:现有的配煤技术多采用煤质较好的原煤和褐煤,应寻求更多的现有资源和褐煤配煤制浆来提高煤浆浓度,尤其是热值不低却未被充分利用的煤炭资源,如煤炭液化废渣、沥青等,以充分利用煤炭资源,保护环境。     

中国水煤浆制备技术的发展

为了应对中国易成浆煤种(炼焦煤)储量少的现状,以神华煤等为研究对象,对其制浆工艺进行了研究。神华煤符合水煤浆对煤质的要求,但属低变质且难制浆煤种。从级配理论入手,开发出新的制浆工艺及配套专用设备和添加剂,可以利用神华煤制取高浓度水煤浆。在此基础上,利用城市污泥和造纸黑液制备生物质煤浆,提高了水煤浆的分散性,同时在工业性锅炉中的燃烧表明:负荷可在45%～100%下连续调节,燃烧效率高达98.66%。此外,分级研磨级配制浆工艺可以使水煤浆质量分数提高3%～5%,系统产能提高30%以上。     

低阶煤气化水煤浆添加剂的评价研究

在低阶煤燃料水煤浆专用添加剂技术的基础上,根据气化用水煤浆的特点与要求,通过调整主体添加剂的分子结构和复配物组分,研制出了性价比高的低阶煤气化用水煤浆专用添加剂,并进行了成浆性试验研究。     

油煤浆中溶剂的黏度与油煤浆黏度关系的研究

安庆芳烃萃取油是理想的煤液化起始溶剂的原料,常压,100℃以下用德国Haake旋转黏度仪测定了不同加氢次数安庆芳烃萃取油的黏度,神华煤液化循环溶剂的黏度及其相对应的干煤浓度为45%的煤浆黏度变化,提供了油煤浆中溶剂的黏度与油煤浆黏度关系的一种方法。     

Study on new solvent extraction systems for erythromycin

New solvent systems for the extraction of erythromycin were studied in which octanol was used as the extractant instead of butyl acetate. The mechanism for these new extraction systems is not simple physical distribution but the formation of a neutral complex of erythromycin. A neutral extraction complex formed between the neutral molecules of erythromycin and extractant by hydrogen bonding, and the formed neutral extraction complex moves into the organic phase. Extraction reaction equations and mathematical models of extraction equilibrium and re‐extraction equilibrium are proposed for these new extraction systems. Experimental results show that the new extraction systems offer technological and economic advantages owing to the low solubility of the extraction solvents in the aqueous phase. The solvent consumption of the new extraction process was less than 3kg per billion active units compared with 9–10 kg per billion active units for a butyl acetate extraction system. In addition, the recovery of solvent from raffinate may be eliminated, thus reducing energy consumption. Copyright © 2005 Society of Chemical Industry     

Multistep extraction of coal

Unlike many natural and synthesized polymers, coal is a mixture of polyfunctional high-molecular-mass material. The usually observed limited extractability of coal is attributed to the disregard of various relatively strong intra- and intermolecular interactions and their co-operativity. Due to the polyfunctionality, ionic, charge-transfer and so-called π-π interactions are present, and their abundances are highly rank-dependent. Such relatively strong interactions are not completely solvated in a single step with any solvent. In this paper, multistep extraction was studied to solvate these interactions. Pyridine was mostly used after treatments to disrupt these interactions without breaking covalent bonds. Much larger pyridine extractability was obtained compared to a single step extraction. As solubilization or extraction is the first step to characterize coal, caution is advised against the limited extractability obtained by conventional procedures.     

水煤浆添加剂及水煤浆稳定性的研究

研究了实验室中制备水煤浆的方法,选择了合适的煤种和适合成浆的煤粉粒度分布。使用了不同分子结构的高分子阴离子型表面活性剂作为添加剂制备水煤浆。研究了不同分子结构的添加剂对同种煤质的水煤浆成浆性的性能比较,选择出了合适的主添加剂。探讨了添加剂的添加量与煤的成浆性、流变性以及静态稳定性的关系。结果表明,添加剂的分子链长短、分子链上的活性基团的多少等因素以及在煤浆中的添加量对水煤浆的成浆性、黏度、质量分数、流变性以及稳定性具有显著的影响。     

油煤浆流变特性研究

为了避免油煤浆输送时发生沉降和无法成浆问题,研究了煤直接液化过程中,煤种、溶胀时间、煤粉加量、粒径和温度等因素对油煤浆性能的影响。结果表明,油煤浆具有假塑性,呈现出优良的"剪切稀化"特性。选用DG41Ti转子进行实验,随着溶胀时间的延长,黏度呈上升趋势,由最初2 h的60 m Pa·s上升为24 h的100 m Pa·s;随着温度的升高,黏度下降,浆体黏度由1 200 m Pa·s下降为130 m Pa·s,降低89.17%;在含油量不变的情况下,煤粉用量最大增至45%。     

Characterization of eluted metal components from coal during pretreatment and solvent extraction

Eluted metals from Enshu (a Chinese) and Stratford (an Australian) coal during pretreatments with methanol/water and dilute acetic acid solutions were characterized and quantitatively analyzed by solid-state ²³Na NMR, cation chromatography, X-ray fluorescence (XRF), and Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES) measurements. To achieve the requirements of solvent extracted coal (namely Hyper-Coal: HPC) for its direct utilization to gas turbine system, alkali and alkali-earth metals such as Na, K, and Ca should be removed from coals. A quantitative analytical method of alkali metals with ICP-AES in combination with flow injection system is established for the evaluation of remaining alkali metal contents, especially for the quantitative analysis of Na concentration in the original coal and its HPC. Microwave irradiation acidic digestion pretreatment under controlled high pressure and temperature is very essential to the prompt and quantitative analyses of all the metals in coals and their derived HPC. Combination of ICP-AES with XRF and/or cation chromatography is also effective for the respective analyses of the residue and the extract or filtrate. Solid-state ²³Na NMR spectra of the coals before and after solvent soaking pretreatment or acetic acid treatment revealed that ion-exchangeable Na species might be rather selectively eluted by these treatments. It is also suggested that the remaining Na species could not be removed by dilute acetic acid solutions.     

Comparison of pressurized liquid extraction with classical solvent extraction and microwave-assisted extraction-application to the investigation of the artificial maturation of Mahakam coal

The pressurized liquid extraction (PLE) technique is validated by the comparison with microwave-assisted extraction and classical solvent extraction of the artificial maturation series of Mahakam coal. PLE extraction can greatly enhance the extraction of asphaltenes and resin under favorable conditions (fine sample dispersion and high extraction temperature). The stability of the thermolabile biomarkers is demonstrated at temperatures up to 100 °C during the PLE process. The molecular maturation indexes derived from the GC-MS analysis of extracts show no significant dependence on the extraction techniques.     

Ionic liquids for coal dissolution,extraction and liquefaction

Coal is the most abundant fossil fuel. Direct combustion of low- and medium-rank coals causes alarming environmental impacts. Therefore, it is crucial for coal to undergo pretreatments before its efficient utilization [such as coal to liquid (CTL) processes]. Conventional pretreatment methods suffer from several limitations including the use of volatile organic solvents, environmental hazards, strong reaction conditions (e.g. high temperature and pressure), consumption of large quantities of nonrecoverable chemicals (e.g. bases used in aqueous alkaline digestion), or being only effective for specific coals. On the other hand, coal pretreatment by nonvolatile ionic liquids (ILs) could lead to partial coal dissolution/swelling and structure disruption, which is a critical step before coal liquefaction, hydrogenation, pyrolysis or the inhibition of oxidation/combustion. In addition, ILs are suitable solvents for extracting sulfur compounds from coal, asphaltenes from Direct Coal Liquefaction Residues (DCLR) and phenolic compounds from coal tar. This review will discuss these aspects of coal pretreatments by ILs, and identify how ILs could lead to a cleaner and more efficient utilization of coal resources. © 2020 Society of Chemical Industry     

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.