超临界流体萃取塔的设计

流体相平衡数据是设计超临界流体萃取塔的关键。本文给出了涉及三元混合物相图计量的萃取塔的可行性研究和应用的一些例子。     

超临界CO_2萃取辣椒油的工艺条件优化研究

以三峡库区种植的辣椒为原料,采用超临界CO2萃取技术,从辣椒中提取辣椒油,考察了萃取温度、萃取压力和萃取时间对辣椒油萃取率的影响。结果表明,萃取温度对辣椒油的萃取率影响最大,其次是萃取压力,萃取时间影响最小;超临界CO2萃取辣椒油的最适宜条件为,萃取温度40℃,萃取压力10 MPa,时间75 min,其萃取率为9.37%;超临界CO2萃取技术应用于辣椒油的提取具有工艺简单、操作安全、能耗低、无毒、萃取剂易回收、萃取率和产品纯度高等优点。     

超临界CO2萃取辣椒油的工艺条件优化研究

以三峡库区种植的辣椒为原料,采用超临界CO2萃取技术,从辣椒中提取辣椒油,考察了萃取温度、萃取压力和萃取时间对辣椒油萃取率的影响。结果表明,萃取温度对辣椒油的萃取率影响最大,其次是萃取压力,萃取时间影响最小;超临界CO2萃取辣椒油的最适宜条件为,萃取温度40℃,萃取压力10 MPa,时间75 min,其萃取率为9.37%;超临界CO2萃取技术应用于辣椒油的提取具有工艺简单、操作安全、能耗低、无毒、萃取剂易回收、萃取率和产品纯度高等优点。     

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。     

超临界CO_2流体萃取植物油的实验研究

建立了一套超临界流体萃取实验装置,就大豆和花生两种植物油超临界流体萃取进行了较为详细的实验研究.在探讨了压力、温度、颗粒度、空隙率以及时间等对萃取率的影响之后,获得了指导实际生产的最佳工艺参数条件.     

Total fatty acid analysis of vegetable oil soapstocks by supercritical fluid extraction/reaction

Soapstock from vegetable oil refining operations is a value-added by-product that finds further industrial use based on its fatty acid content. Since the fatty acid content of soapstock can vary according to its vegetable oil source or method of refining, determination of its total fatty acid (TFA) by an accurate analytical method is of key importance to purchasers of this refinery by-product. Traditionally, the TFA content of soapstock has been determined by the AOCS Official Method G3-53 based on a gravimetric assay. Unfortunately, this gravimetric-based assay requires considerable time and incorporates a considerable quantity of organic solvent per assay. In this study, the authors have applied supercritical fluid extraction (SFE) with an enzymatic-based reaction (SFR), in the presence of supercritical carbon dioxide (SC-CO₂), to determine the TFA content of soapstocks. The SFE/SFR sequence was conducted using two commercially available extractors using an in situ supported lipase in the extraction cell to form fatty acid methyl esters (FAME). Gas chromatographic (GC) determination of the individual FAME, followed by quantitation based on the calculated sum of all the fatty acids from the GC analysis, allowed a precise determination to be made of the soapstock’s TFA content. The TFA contents of three different soapstocks determined by this method were slightly higher than the values derived from Official Method G3-53. The reported method takes less than one-half of the time of Official Method G3-53 and reduces organic solvent use from 575 mL to under 2 mL of solvent by using SC-CO₂.     

Supercritical fluid extraction to determine the oil content in copra and extracted meal

Supercritical fluid extraction (SFE) was used as a primary method to determine the oil content of copra and its meal. Determination of the oil content of copra takes 9 h, and for meal 6 h are necessary with Soxhlet extraction, whereas SFE determined oil contents in about 10 min. The extremely high oil content of copra makes grinding difficult, as the sample becomes very gummy and it is difficult to remove the entire sample from the grinder. Adding diatomaceous earth to the sample before grinding eliminated the difficulties of cleaning the grinder and also enabled very fast SFE extractions. The variances for Soxhlet and SFE were not significantly different from each other (P>0.10) in both copra and meal oil contents. The 95% confidence interval around the mean differences (SFE-Soxhlet) was (−0.35, 0.90) and (0.08, 0.26) and for copra and meal, respectively. Although the SFE meal oil content (9.81%) was significantly higher than the Soxhlet meal oil content (9.64%), the size of the average difference (0.17%) was relatively small. This small difference was considered acceptable owing to the ability to use SFE in real-time process control. Therefore, SFE can be used to determine the oil content in copra and its meal in less than 10 min.     

Determination of heavy hydrocarbon contamination using supercritical fluid extraction with infrared detection

Supercritical fluid extraction (s.f.e.) conditions to extract heavy hydrocarbons quantitatively from soil were developed, using high temperature (150 °C) and an infrared-clear organic solvent. S.f.e. with pure CO₂ at 65 °C gave good recovery of light crude oil components ( C25 alkanes) but did not efficiently extract heavier components. An increase in temperature during s.f.e. to 150 °C increased the recovery of the heavier hydrocarbons, but the best recoveries were achieved by extraction at 150 °C after addition of perchloroethylene as a modifier. Under these conditions s.f.e. (15 min static followed by 15 min dynamic extraction) gave recoveries 5–45% higher than did 4 h of Soxhlet extraction for soils contaminated with light to heavy crude oils, motor oil and heavy residual oil. Adsorption of the extracted polar compounds on silica indicated that both polar and non-polar organics were more efficiently extracted by s.f.e., Since the modifier is added directly to the soil sample, the method does not require either dual pumps or premixed fluids.     

超临界流体萃取技术发展新动向

介绍了超临界流体萃取技术发展新动向、新应用领域开发的实例以及基础研究工作     

Preparative-scale supercritical fluid extraction/supercritical fluid chromatography of corn bran

A preparative-scale supercritical fluid extraction/supercritical fluid chromatography (SFE/SFC) procedure has been developed for the removal of oil from corn bran to obtain fractions enriched with free sterols and ferulate-phytosterol esters (FPE). Operational parameters from an analytical-scale supercritical fluid fractionation technique were translated to and optimized on a home-built, preparatory-scale SFE/SFC apparatus. SFE was performed at 34.5 MPa and 40°C using supercritical carbon dioxide. These conditions did not result in exhaustive extraction of the corn bran, but yielded about 96% of the available oil. SFC was conducted in three steps, followed by reconditioning of the sorbent bed. Preparative-scale SFE/SFC of corn bran produced a fraction enriched greater than fourfold in free sterols and 10-fold in FPE, suggesting that such a scheme could be used industrially to produce a functional food ingredient.     

Comparison of different methods for the determination of the oil content in oilseeds

The investigation and assessment of the oil content of oilseeds are important criteria, especially for the oil milling trade. Standard methods for the determination of the oil content of oilseeds are very time consuming, with extraction periods of 4 to 8 h. Three different oilseeds—rapeseed, sunflower, and soybean—are extracted by supercritical fluid extraction (SFE), accelerated solvent extraction, microwave-assisted extraction, solid fluid vortex extraction, and Soxtherm, and the results are compared with the result of the German Fat Science Society (DGF) standard method B-I 5 (87). Besides, the extracts are analyzed regarding the content of tocopherols as a parameter for mild extraction conditions and the content of diglycerides and free fatty acids as parameters for the content of more polar lipids. The results of the determination of the oil content under optimal conditions are comparable with the results of the DGF standard method B-I 5 (87). There are no significant differences between the different methods. The content of tocopherols is dependent upon the extraction method and the type of oilseed. The highest content is obtained by SFE. The content of diglycerides and free fatty acids varied according to the oilseed.     

超临界流体萃取技术的应用及研究进展

超临界流体萃取技术近年来被广泛应用于中草药、食品、香料、化工及环境保护等领域。介绍了超临界流体萃取技术与传统的萃取方法相比所具备的优势及其发展前景。     

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.     

超临界流体萃取脱除人参中痕量有机氯农药

利用在线固相吸附柱收集,淋洗剂洗脱超临界流体萃取出的真实人参样品中的有机氯农残实验,确定最佳的吸附柱和淋洗剂。通过实验确定利用C18作吸附剂,用正己烷洗脱可取得最优效果。此外,还对直接冷凝收集法、索氏提取法与固相吸附柱收集法进行了对比。     

An improved micro-extraction cell for supercritical fluid extraction and chromatography of fatty acids

An improved supercritical fluid micro-extraction cell of increased reliability was designed for on-line supercritical fluid extraction and chromatography (SFE/SFC) of food and other lipid-related samples. The key components in the modified cell include a Swagelok stainless steel reducing union with a dual ferrule as the cell, with polyetherether-ketone (PEEK) ferrules and nuts to connect the cell to the control valve. The new cell did not leak under all conditions examined (100–500 atmospheres, 40–80°C), even after numerous extractions (>250). The quantitative performance of the cell was evaluated with fatty acid standard solutions, technical grade fatty acid sources and wheat flour. The percent relative error (%RE) for the fatty acid standards and technical-grade fatty acid samples was ≤6.0% for oleic, linoleic and linolenic acid. The %RE for oleic and linoleic acid in the whole-wheat samples was ≤10%. The results demonstrate that the new extraction cell can be used for quantitative extractions and that the sensitivity of the SFE/SFC technique is excellent. Similar SFE/SFC methods could prove useful in studying the interaction of free fatty acids with various food components such as enzymes, amylose and proteins.     

超临界CO2流体萃取中的在线检测技术

综述了超临界CO2流体萃取中的在线检测技术,介绍了超临界CO2流体萃取与超临界流体色谱、气相色谱、高效液相色谱、核磁共振、近红外光谱等技术的联用在线检测,阐述了在线检测技术的优越性,提出了如何发展超临界CO2流体萃取中的在线检测技术。     

均匀设计法优化超临界萃取姜油树脂工艺条件的研究

采用均匀设计法,考察了CO2超临界萃取过程中萃取压力、萃取温度、萃取时间及萃取剂CO2流量4个因素对姜油树脂萃取率的影响。结果表明,超临界萃取姜油树脂的最佳工艺条件为:萃取压力30 MPa,萃取温度50℃,萃取时间4.5 h,CO2流量为26 kg/h,在此条件下,姜油树脂萃取率为5.27%。     

超临界流体萃取塔的应用设计及理论研究

设计了超临界流体萃取塔系统，并对其流体力学特性和传质性能进行了研究，为工业设计提供了理论依据。在连续逆流操作的超临界填料萃取塔、筛板萃取塔和喷淋萃取塔中，应用超临界二氧化碳-异丙醇-水、超临界二氧化碳-乙醇-水两种实验体系对流体力学模型和传质模型进行了实验验证，计算结果与实验数据符合较好。     

Supercritical fluid extraction of walnut kernel oil

The objective of this study was to investigate the effects of the main process parameters on supercritical fluid extraction of walnut (Juglans regia L.) kernel oil. The recovery of walnut kernel oil was performed in a green and high-tech separation process. CO₂ and CO₂ + ethanol mixtures were used as the supercritical solvent. The extraction was carried out at operating pressures of 30, 40 and 50 MPa, operating temperatures of 313, 323 and 333 K, mean particle sizes of 1.78×10⁻⁴, 3.03×10⁻⁴, 4.78×10⁻⁴, 7.00×10⁻⁴ and 9.00×10⁻⁴ m, supercritical CO₂ (SC CO₂) flow rates of 1.67×10⁻⁸, 3.33×10⁻⁸, 6.67×10⁻⁸ and 13.33×10⁻⁸ m³/s and entrainer (ethanol) concentrations of 2, 4, 8 and 12 vol-%. Maximum extraction yield and oil solubility in SC CO₂ obtained at 50 MPa, 333 K, 9.00×10⁻⁴ m, 3.33×10⁻⁴ m³/h were 0.65 kg oil/kg of dry sample and 37.16 g oil/kg CO₂, respectively. The results obtained in this study showed that the crossover pressure effect of walnut kernel oil was at 30 MPa. At 30 MPa and 313 K, the obtained extraction yields above 4 vol-% ethanol reached the organic solvent extraction yield of 68.5 kg oil/kg dry sample. Extraction time was decreased significantly because of the higher solubility of walnut kernel oil in SC CO₂ + ethanol mixtures.     

超临界流体技术在环境保护中的应用研究

综述了超临界流体技术在环境保护各领域的应用。介绍了国内外超临界流体技术 (超临界水反应、超临界萃取以及超临界色谱 )处理环境污染物的实例