不同溶剂神府煤超临界萃取研究

本文以我国新开发的特大煤田——神府煤为研究对象,在半连续装置上,以水、甲苯以及水和甲苯中分别加入少量四氢萘为溶剂进行超临界萃取研究。详细地考察了无机溶剂水、有机溶剂甲苯及供氢溶剂四氢萘对萃取过程的影响。实验结果表明,超临界萃取是神府煤的有效利用途径之一,萃取物产率是铝甑焦油产率的2.65～5.72倍,萃取物中以预沥青烯为主要族组分;以甲笨为溶剂,萃取率高于以水为溶剂的;在水及甲苯中加入少量四氢萘,均可以大幅度地提高萃取率。     

油页岩溶剂萃取研究现状与展望

介绍了最近几年来国内外油页岩溶剂萃取技术应用进展,重点阐述了温和条件溶剂萃取法、添加剂辅助溶剂萃取法、微波辅助溶剂萃取法以及超临界流体萃取法等4种国内外比较成熟的萃取方法,讨论了各种油页岩溶剂萃取技术实行商业化运行的可行性,最后展望了油页岩溶剂萃取技术发展前景.     

先锋褐煤CO／H2O超临界萃取研究

在不同ＣＯ初压、不同催化剂作用下，以ＣＯ／Ｈ２Ｏ为溶剂对云南先锋褐煤进行超临界萃取，对萃取物的族组成进行了＾１Ｈ，＾１３Ｃ－ＮＭＲ分析。结果表明：萃取产率和转化率随ＣＯ初压增大而增加；ＣＯ和Ｈ２Ｏ可发生变换反应生成中间态活泼氢，从而具有较哟的供氢能力，使萃取产率和转化率提高；碱金属的氢氧化物及碳酸盐对ＣＯ／Ｈ２Ｏ变换反应有较强的催化作用；萃取物的油组分以单环芳香结构为主，具有较高的Ｈ／Ｃ比和较多的     

溶剂组成对褐煤催化液化的影响

本文采用60ml微型高压釜,以杂酚油为溶剂,在氨初压6.0MPa,反应温度400℃,反应时间30min的条件,以四氢萘,邻苯二酚为模型化合物,考察了溶剂中供氢组分和酚类物质对先锋褐煤催化液化的影响.实验结果表明,供氢组分对液化转化率和油品产率皆有重要作用;酚类物质对液化转化率影响较小,但能改变液化产物之间的分布,催化剂活性是随溶剂中供氢组分和酚类物质百分含量的改变而发生变化.     

有机溶剂萃取加拿大油砂应用研究

介绍了溶剂作为萃取剂分离油砂的技术,溶剂萃取油砂过程包含两个阶段:沥青相向溶剂的溶解过程和沥青、溶剂与砂粒的分离过程。考察了单一溶剂甲苯、丙酮、乙酸乙酯和甲苯/正庚烷、丙酮/正庚烷、乙酸乙酯/正庚烷组成的复合溶剂体系在相同条件下对油砂沥青的萃取率,在此基础上进一步对比了不同溶剂体系对沥青四组分饱和分、芳香分、胶质和沥青质的萃取效果,同时考察了不同浓度的沥青-溶剂溶液的表面张力,结果表明在油砂萃取过程中沥青-溶剂体系的表面张力主要取决于所选溶剂的种类,而沥青的浓度对溶液表面张力的影响不大。混合溶剂体系甲苯/正庚烷、丙酮/正庚烷、乙酸乙酯/正庚烷相比纯溶剂萃取率较高,其沥青溶液表面张力较低,是良好的分离油砂溶剂体系。     

不同溶剂可保煤超临界萃取产物成分分析

选用了我国适于液化的褐煤──可保褐煤为原料，在半连续装置上，以甲苯、水及水／一氧化碳体系中加入少量氢氧化钠为溶剂进行超临界萃取研究。萃取物分离成油、沥青烯及前沥青烯三个族组分。ＧＣ／ＦＴＩＲ的分析结果表明，可保煤水萃取产物主要是含氧有机物、少量的烃类及烃类衍生物。在水／一氧化碳体系中加少量氢氧化钠催化剂萃取的产物主要是烃类及其衍生物。     

煤的超临界萃取液化特征

在半连续装置上，选用几种褐煤、烟煤及乐平煤进行了超临界水萃取液化研究。对反应活性较高的可保煤和乐平煤考察了不同溶剂、不同催化剂、不同温度段及不同压力对萃取结果的影响。对特征煤－乐平煤的萃取物进行了ＧＣ／ＦＴＩＲ和ＦＴＩＲ分析。结果表明：以甲苯为溶剂，在４００￣４３０℃时萃取率较高，ＮａＯＨ催化剂可提高萃取物中油含量。乐平煤萃取物主要是苯类、烷烃类衍生物。     

超临界条件下甲苯歧化反应催化剂活性的研究

<正> 1 引言 超临界流体中的化学反应过程具有许多潜在的优势,是近年来十分活跃的研究领域.超临界流体中进行化学反应可以原位维持非均相催化剂的活性,这方面的工作只见简单模型反应的实验报道,缺乏对有关机理的探索。目前工业上甲苯歧化为临氢操作以改善催化剂的稳定性,延长寿命。本实验研究的目的是利用超临界流体的特点,探索不临氢超临界条件下,改善催化剂稳定性,延长寿命,开发甲苯歧化新工艺的可能性。为此,本文对超临界甲苯(T_c=597.1K,P_c=4.23MPa)在ZSM-5和丁-Al_2O_3上歧化反应的催化剂活性进行了实验研究,并对有关机理进行了讨论。     

超临界CO2萃取技术在天然产物提取中的应用

文章论述了国内外超临界CO2萃取技术进行天然产物提取的开发利用现状、与传统提取方法相比具有的优越性、以及在现代工业生产中的应用现状和前景,并通过实验考察了超临界CO2萃取技术从万寿菊中提取叶黄素的工艺条件,结果表明在提取时间和叶黄素提取量上都优于传统溶剂提取法.最后对超临界CO2萃取技术应用于天然产物提取的前景进行了展望.     

硫磺新溶剂研究

为了解决硫磺溶解过程中硫磺溶剂种类选择少、要求高问题,考察四氢萘、苯乙烯、十氢萘和甲苯4种溶剂在30～90℃下对硫磺的溶解度.实验结果表明4种溶剂对硫磺的溶解度均随温度升高而增大,在相同温度下,四氢萘对硫磺的溶解度最大,90℃时对硫磺的溶解度可达13.31 g/100 9溶剂,苯乙烯次之,甲苯在30～70℃对硫磺的溶解度略大于十氢萘,超过70℃,十氢萘对硫磺的溶解度大于甲苯.     

Comparative studies on the yield and quality of oils extracted from Moroccan oil shale

In the present work, the effect of solvent on the sub and supercritical extraction of the organic matter from Tarfaya's oil shales was studied. The experimental results revealed that the extraction yield obtained by the phenol is very high compared to that obtained by the toluene or without solvent. In addition, the solvent had a significant effect on the yield and the composition of the obtained oil. The analyses carried out on the recovered oils allowed us to establish that the phenol is a very efficient solvent for oil shale extraction, giving a better quality of the oils extracted containing a large proportion of maltenes and aromatics compounds and fewer amounts of sulphur and paraffin compounds.     

Recovery of grape seed oil by liquid and supercritical carbon dioxide extraction: a comparison with conventional solvent extraction

In this work the extraction of grape seed oil by means of liquid and supercritical carbon dioxide as solvent is described. The operating conditions to determine the maximum extraction yield were studied. The efficiency of supercritical fluid extraction (SFE) was similar to that obtained by conventional liquid extraction, but the quality of the supercritically extracted oil was higher, equivalent to a degummed, liquid- extracted oil. It is considered that SFE is competitive with conventional liquid extraction, because the solvent distillation and oil refining stages can be omitted.     

Extraction of El-Lajjun Oil Shale

Abstract

Extraction of the bitumen fraction of El-Lajjun oil shale was carried out using 17 different solvents, pure and combined. Out of all the solvents used, toluene and chloroform were found to be the most efficient for extraction of the bitumen to perform the major part of the experiments. This selectivity was based on the quality and quantity of the yield and on the quantity of solvent recovered. Extraction was carried out using a Soxhlet extractor. For complete recovery of solvent the extract phase was subjected to two stages of distillation, simple distillation followed by fractional distillation, where different cuts of oil were obtained. It was found that an optimum shale size of 1.0 mm offered better solvent recovery. One hour was the optimum time needed for complete extraction. The yield of oil was determined from the material balance gained from fractional distillation after testing for the existence of any traces of solvent trapped in the different cuts by using a gas chromotography technique. When chloroform was used, it was found that the average amount of bitumen extracted was 0.037 g/g of shale, which corresponds to 98% of the actual bitumen trapped in the oil shale (by assuming the bitumen represents 15% of the organic matter) and 84.1% of solvent recovered. When toluene was used, it was found that the average amount of oil extracted was 0.0293 g/g of shale, which corresponds to 78% of the actual bitumen trapped in the oil shale (by assuming bitumen represents 15% of the organic matter) and 89.9% of solvent for extraction with toluene.     

Composition of the products of the supercritical benzene extraction of combustible shale from the Kashpirskoe deposit

A change in the group composition of the liquid products of the supercritical fluid extraction of combustible shale under nonisothermal conditions at various solvent pressures was found. As the solvent pressure was increased, the yield of liquid products was found to increase mainly at the expense of high-molecular-weight substances (preasphaltenes and asphaltenes).     

Development of Pressurized Extraction Processes for Oil Recovery from Wild Almond (Amygdalus scoparia)

Wild almond Amygdalus scoparia is a very fruitful tree that is spread over an extensive region of Iran. Considering its high quality oil, the development of clean extraction processes based on the use of compressed fluids is encouraged. In this study, the main factors involved in supercritical fluid extraction (SFE) and pressurized liquid extraction (PLE) of wild almond have been optimized by using two different experimental designs and considering the oil extraction yield as a response variable; effects of time, temperature, pressure, and use of co‐solvents were studied for SFE while effects of time, temperature and type of solvent were evaluated for PLE. Results showed that the maximum oil yield using supercritical carbon dioxide was 42 %, obtained under the following conditions: extraction temperature, 40 °C; extraction pressure, 40 MPa; and 10 % ethanol as co‐solvent. The optimum extraction yield for PLE was 55 %, which was achieved using ethanol as solvent at 150 °C for 20 min. Lipidomic analysis revealed that the amount of oleic acid in the oil extracted by SFE was higher than those obtained by using other classical procedures. In addition, triacylglycerols constituted more than 98 % of the extracted oils.     

超临界CO_2和微波辅助萃取当归挥发油

考察当归挥发油的不同提取方法。文中用超临界CO2流体萃取法和微波辅助萃取法研究萃取当归挥发油。实验表明:超临界CO2萃取最佳工艺条件为萃取压力25 MPa、分离釜Ⅰ解析温度55℃、萃取温度45℃,提取率约1.9%;微波辅助萃取最佳工艺条件为无水乙醇为提取溶剂,微波功率800 W、微波辐射时间150 s、液料质量比为4.71∶1,提取率约11.2%。微波辅助萃取法取得当归油的收率高于超临界CO2萃取法。微波辅助萃取法萃取当归挥发油收率高,但外观品质较超临界萃取的当归挥发油差。     

CO2 supercritical fluid extraction of Jordanian oil shale utilizing different co-solvents

In this study, extracting shale oil from Jordanian oil shale using supercritical fluid extraction has been investigated. Experimental data indicates that by using supercritical extraction with carbon dioxide, using co-solvents can be viable. A relatively high yield can be obtained at relatively moderate pressure. At the highest temperature and pressure of 450 °C and 3200 psi, respectively, and with hexane as a co-solvent, the highest yield obtained was 100 kg/ton of oil shale, which was at the highest temperature and pressure of 450 °C and 3200 psi, respectively, and with hexane as a co-solvent. Increasing both the operating pressure and temperature increases the oil yield. In the supercritical state, carbon dioxide along with other co-solvents, such as hexane and acetone, interact with the kerogen leading to the dissolution of fragments due to an increase in solubility and mass transfer.Increasing the particle size of oil shale for extraction decreases the oil yield. Most of the extracted oil obtained is saturated hydrocarbons, olefinic and a portion of aromatic hydrocarbons. As the extraction temperature increases, the production of low-molecular weight compounds increases.     

Effect of toluene proportion on the yield and composition of oils obtained by supercritical extraction of Moroccan oil shale

Supercritical extraction of Tarfaya's oil shale by toluene revealed that the solvent proportion has a significant effect on the yield and the composition of the obtained oils. The analyses carried out on the recovered oils allowed to establish the optimal operating conditions giving the highest oil yields. In addition, it was observed that these oils contain a large proportion of aromatics compounds.     

Thermal dissolution of oil shale in benzene with an ethanol additive under supercritical conditions

The results of the thermal dissolution of oil shale from some deposits in Russia in a benzene solvent under supercritical conditions in a semiflow system are reported. It was found that the addition of ethanol significantly increased the yield of liquid products due to the hydrogenating and alkylating properties of the alcohol.     

A Comparative Study on Response Surface Optimization of Supercritical Fluid Extraction Parameters to Obtain Portulaca Oleracea Seed Oil with Higher Bioactive Content and Antioxidant Activity Than Solvent Extraction

Portulaca oleracea (purslane) seed oil is a rich source of omega-6 and omega-3 fatty acids. Extraction of the purslane seed oil while preserving its high nutritive quality has been a challenge since conventional solvent extraction has many adverse effects on bioactive content. This study aims the optimization of purslane seed oil supercritical fluid extraction (SFE) conditions and to compare purslane seed oils obtained with SFE and conventional solvent extraction in terms of oil yield, along with the purslane seed oil quality and bioactive content. For this purpose, the SFE process parameters (pressure, temperature, static time, and dynamic time) are optimized for oil yield, omega-6, omega-3, and antioxidant activity using response surface methodology (RSM). Optimum SFE pressure, temperature, static time, and dynamic time levels are determined as 350 bar, 50 °C, 20 min, and 90 min, respectively. Oil yield and physicochemical quality properties of conventional solvent extract and SFE samples are determined and compared. Consequently, samples obtained via SFE and solvent extraction have similar quality properties. Distinctly, SFE allows an extraction with 5.6% higher total phenolic compound (TPC) and 33% higher antioxidant activity than solvent extraction. Practical Applications: In the study, the extraction of purslane oil using supercritical fluid extraction is optimized with different approaches. At optimum conditions, purslane oil is extracted and all physicochemical properties and the process efficiency (yield) are compared with the solvent-extracted samples. The results of this study make supercritical fluid extraction of purslane seed oil possible since all optimum operating conditions of a pilot-sized extractor are reported in the study. It is believed that the results provide a good starting point for industrial operations. Moreover, researchers also believe that research studies unveiling the new potential oil-bearing seeds are important to overcome the vegetable oil shortage that emerged this year.