Mathematical modeling of extraction of egg yolk oil with supercritical CO2

Extraction of egg yolk oil (EYO) from egg yolk powder (EYP) with supercritical CO₂ was performed on a laboratory apparatus. Solubility of EYO in supercritical CO₂ was measured. The external diffusion and the equilibrium between solid and fluid phases were experimentally found to be the controlling steps during the extraction process. Based on this mechanism, a mathematical model for this extraction process was developed. The model parameters, adsorption equilibrium constant (k_p), EYO concentration in solid controlling the transition in the equilibrium (x_k) and the overall volumetric mass transfer coefficient (K_fa_p), were obtained by simulation. The simulation results indicated that x_k is 0.56, K_fa_p is directly proportional to CO₂ flow rate with an exponent of 0.548, and the adsorption heat of EYO is 6–9 kJ mol⁻¹. The model was verified by concentration profiles of solid. The extraction process of EYO with supercritical CO₂ was conducted on a pilot plant and the developed model could predict satisfactorily the process.     

Supercritical CO2 extraction of Plumula nelumbinis oil: Experiments and modeling

Supercritical CO₂ extraction of Plumula nelumbinis oil was investigated at temperatures of 308–338 K and pressures of 15–45 MPa. The yield of the extracted oil was 0.128 g/g material at optimal conditions, in which gamma-sitosterol, unsaturated fatty acids and gamma-tocopherol had higher relative concentrations as determined by GC–MS. The broken and intact cell (BIC) model, with reduced adjustable parameters, was utilized to simulate the SFE process. The values of average absolute relative deviation (AARD) were in the range 2.34–10.9%, indicating that the improved method had a similar effect to the BIC model when three parameters were adjusted. The parameters obtained during the modeling had clear physical meanings and were used to gain an in-depth understanding of the SFE process theoretically.     

Petroleum-free extraction of oil from soybeans with supercritical CO2

Full-fat soyflakes are readily extracted with supercritical carbon dioxide (SC-CO₂) at pressures of 3,000~10,000 psig and 50 C. Under these conditions, SC-CO₂ has the density of a liquid and the diffusivity of a gas. Therefore, equilibrium solubility is readily achieved in a short-path batch extractor which permits high gas flow rates. Soybean oil extracted with SC-CO₂ is lighter in color and contains less iron and about one-tenth the phosphorus of hexane-extracted crude oil from the same beans. The lower phosphorus content is reflected in a chromatographic refining loss of 0.6% compared to 1.9% for hexane crude. Refined oils from hexane and SC-CO₂ extraction had equivalent odor and flavor scores initially and after 4 days' storage at 60 C. Carbon dioxide, an ideal solvent for extraction of food products, is low-cost and readily available from fermentation processes and could free over 20 million gallons of costly hexane per year for essential energy uses.     

Oxidative stability of sunflower oil extracted with supercritical carbon dioxide

Extraction of oilseeds with supercritical carbon dioxide (SC−CO₂) is a promising technique to obtain vegetable oils. However, instability of such oils has been associated in the past with SC−CO₂ extraction. The reasons underlying such instability were unclear. Results presented here suggest that oil instability may be related to the oxygen content of CO₂. In fact, oil stability decreases sharply when refined oil (additive-free) is re-extracted with SC−CO₂ and can be related to the oxygen content in the CO₂. Never-theless, oil stability could be improved to the level of conventionally extracted oil by adding trace amounts of ascorbic acid.     

Supercritical fluid extraction of sunflower seed oil with CO2-ethanol mixtures

The effect of ethanol addition to supercritical carbon dioxide (SC-CO₂), up to 20%, on sunflower seed oil extraction over the range of 150 to 350 bars and 42 to 80°C was studied. A nonrecirculating home-made bench-scale system was used as extraction equipment. The oil-SC-CO₂-ethanol mixture was reduced to atmospheric pressure in a test tube, where two phases, oil and ethanol, were obtained and ethanol-saturated CO₂ was liberated to the atmosphere. Results show that sunflower oil solubility in SC-CO₂ greatly increases with addition of ethanol as entrainer over the whole range of pressure and temperature conditions. Some phospholipids are co-extracted at levels directly proportional to the added ethanol. Moreover, a large amount of phospholipids was recovered in the ethanolic phase. Acidity of the extracted oil with ethanol as entrainer was lower than that without alcohol. Part of the free fatty acids was found in the ethanolic phase.     

Experimental studies and discrete thermodynamic modeling on supercritical CO2 extractions of a hexadecane and crude oil

Continuous multiple-contact experiments using a supercritical CO₂ were performed to study the phase equilibrium behavior of the dynamic extractions of a hexadecane and crude oil. The extraction yields increased as CO₂ density increased with a pressure rise at constant temperature. The rates of extractions were also greater at higher pressure. The simulated distillation analysis of extracted crude oil samples represented that the earlier extracts contained lighter compounds and the latter extracts contained progressively heavier compounds. These compositional changes occurring during a dynamic extraction were also ascertained by phase-equilibrium flash calculations using the equations of state and a pseudo-component lumping method. Two different equations of state, Soave-Redlich-Kwong and Peng-Robinson, were used to predict the equilibrium compositions of the extract phase that is a supercritical carbonic phase. The results of phase behavior calculations established the nature of the extraction and partitioning process as a function of time. These results also provided reasonable agreement between the experimental data and the calculated values.     

用超临界CO2萃取技术处理高浓度有机废水

采用CO2超临界流体萃取(SFE-CO2)法,对含有高浓度极性有机物苯酚及少量丙酮、苯、苯胺、硝基苯的化工废水进行处理.运用正交实验法考察压力、温度、萃取时间、萃取流量以及夹带剂对萃取率的影响.通过测定原水和已处理水的CODCr来评价总的处理效果,用气相色谱测定萃取产物的量,得到各有机物在不同萃取条件下的萃取率,找到了萃取该废水的最佳工艺条件.最佳CODCr去除工艺条件为40 MPa、70℃、30 L/h、80 min,最佳条件下CODCr去除率可达98.8%以上.实验表明不宜采用乙醇或乙酸乙酯作夹带剂.     

Measurements and modeling of PS/supercritical CO2 solution viscosities

This paper presents a technology to determine the melt viscosity of a PS/super-critical CO₂ solution using a linear capillary tube die mounted on a foaming extruder. CO₂ was injected into the extrusion barrel and the content of CO₂ was varied in the range of O to 4 wt% using a positive displacement pump. Single-phase PS/CO₂ solutions were formed using a microcellular extrusion system and phase separation was prevented by maintaining a high pressure in the capillary tube die. By measuring the pressure drop through the die, the viscosity of PS/CO₂ solutions was determined. The experimental results indicate that the PS/CO₂ solution viscosity is a senstive function of shear rate, temperature, pressure, and CO₂ content. A theoretical model based on the generalized Cross-Carreau model was proposed to describe the shear-thinning behavior of PS/CO₂ solutions at various shear rates. The zero-shear viscosity was modeled using a generalized Arrhenius equation to accommo-date the effects of temperature, pressure, and CO₂ content. Finally, the solubility of CO₂ has been estimated by monitoring the pressure drop and the absolute pressure in the capillary die.     

楝树杀虫成分苦楝素的超临界CO2萃取

苦楝素是楝科植物中制备植物源农药的主要杀虫成分.针对不同种源楝树的皮、叶及果实,采用溶剂浸提法提取筛选苦楝素含量较高的种源作为实验原料,采用乙醇提取,考察液固质量比、提取时间和提取次数等参数对苦楝素提取率的影响.当液固质量比为25∶ 1、提取时间为4 h、提取次数为3次时,苦楝素的提取率达18%.进一步采用超临界CO2...     

超临界CO_2萃取辣椒油实验研究

研究了利用超临界CO2为萃取剂,从辣椒中萃取分离辣椒油的工艺。考察了萃取压力、萃取温度、辣椒原料颗粒大小以及CO2流量等因素对辣椒油萃取率的影响。结果表明,最佳工艺参数为:压力22 MPa,CO2流量0.3~0.4 m3/h,颗粒度30~50目,温度315 K。超临界萃取法具有工艺简单、操作安全、产品无溶剂残留、提取率高等优点。     

Extraction of jojoba seed oil using supercritical CO2+ethanol mixture in green and high-tech separation process

In this study, the extraction of jojoba seed oil obtained from jojoba seed using both supercritical CO₂ and supercritical CO₂+ethanol mixtures was investigated. The recovery of jojoba seed oil was performed in a green and high-tech separation process. The extraction operating was carried out at operating pressures of 25, 35 and 45 MPa, operating temperatures of 343 and 363 K, supercritical fluid flow rates of 3.33 × 10⁻⁸, 6.67 × 10⁻⁸ and 13.33 × 10⁻⁸ m³ s⁻¹, entrainer concentrations of 2, 4 and 8 vol.%, and average particle diameters of 4.1 × 10⁻⁴, 6.1 × 10⁻⁴, 8.6 × 10⁻⁴ and 1.2 × 10⁻³ m. It was found that a green chemical modifier such as ethanol could enhance the solubilities, initial extraction rate and extraction yield of jojoba seed oil from the seed matrix as compared to supercritical CO₂. In addition, it was found that the solubility, the initial extraction rate and the extraction yield depended on operating pressure and operating temperature, entrainer concentration, average particle size and supercritical solvent flow rate. The solubility of jojoba seed oil and initial extraction rate increased with temperature at the operating pressures of 35 and 45 MPa and decreased with increasing temperature at the operating pressure of 25 MPa. Furthermore, supercritical fluid extraction involved short extraction time and minimal usage of small amounts entrainer to the CO₂. About 80% of the total jojoba seed oil was extracted during the constant rate period at the pressure of 35 and 45 MPa.     

超临界CO2破碎生姜细胞壁萃取精油

采用超临界CO2萃取生姜精油,设计了一个突然降压的过程,使生姜块茎的细胞壁破碎,减少过程的传质阻力。通过L18(37)正交试验得出其最优的工艺条件为:破碎压力20.0MPa,恒压时间30min,降压速率为10.0MPa/min,萃取压力16.0MPa,萃取温度45℃。在CO2流量为20.0m3/h时,萃取60min可完成操作。与索氏(溶剂)提取法相比,其收率很高(约3.62%);与超临界CO2萃取法相比,该方法的萃取温度、萃取压力和操作时间有较大降低,产品收率提高1.32倍;据此设计的150L中试装置,经过4000h的试运行证明,该装置用于萃取姜油可完全满足工艺要求。     

超临界CO2萃取川芎中药效成分研究

研究了超临界CO2萃取中药材川芎中的药效成分的工艺条件,以阿魏酸为质量控制指标,分析了多种因素的影响。实验结果表明,在45—65℃、30—50 MPa的条件下,川芎提取率可达到3.75%—4.77%,但提取物中的阿魏酸质量分数仅为0.1%左右。进一步考察了夹带剂的种类及添加方式对提取的影响,结果表明,当以乙醇为夹带剂,其添加质量为物料1.6倍时进行超临界CO2萃取,提取率高达8.24%,阿魏酸质量分数为0.735%,均比传统渗漉法有较大提高。     

超临界CO2萃取万寿菊籽油的工艺研究

本文运用超临界CO2萃取技术提取万寿菊籽油,采用正交设计实验法,研究了温度、压力、萃取时间及CO2流量对籽油提取率的影响,以提取率最大为目标,确定了最佳工艺条件,并对万寿菊籽油进行了感官评定.实验结果表明最佳提取条件萃取时间3h,压力35MPa,温度40℃,CO2流量在20～40kg·h-1.籽油透明、橙黄、无异味,酸价为46.93mg KOH/g油,碘值为50.17g/100g.     

Process optimisation in sunflower oil extraction by supercritical CO2

A continuous process for the extraction of sunflower oil using supercritical CO₂, featuring multiple extractors, one oil separator and three cascaded CO₂ recovery vessels operating at different pressures, was devised and studied. For every single equipment of the plant making up the process a mathematical model was built. Experimental tests—consisting in measurements of oil solubility in supercritical CO₂—were carried out in a laboratory-scale apparatus to characterise the behaviour of sunflower oil in the separation from the supercritical fluid. The mathematical model of the whole process was coded in the commercial gPROMS process modelling environment where both its simulation and optimisation—this latter assuming the overall oil production cost as the objective function—were carried out. The process- and economics-related results are discussed and compared with those obtained with traditional and cold-pressing extraction.     

Extraction of oil from chia seeds with supercritical CO2

Chia (Salvia Hispanic, L.) is a crop that was used as food, medicine and paints by the Aztec Indians in Mexico before 1492, and now has a promissory future in several countries. Chia seeds oil is rich in polyunsaturated fatty acids, particularly omega-3 linolenic acid (54-67%) and omega-6 linoleic acid (12-21%) which pose great benefits for human and animal health.The oil extraction from Chia seeds using supercritical CO₂ seems to be a good alternative because it operates at low temperature with good mass-transfer rates and with no solvent residual in the final product.The objective of this work is to evaluate the extraction yield of oil from chia seeds and the concentration of omega-3 and omega-6 acids using supercritical extraction with CO₂ at three pressures: 136, 272, and 408 bar, and three temperatures: 40, 60, and 80 °C.     

Processing naproxen with supercritical CO2

Naproxen has been processed with supercritical fluids in order to improve the dissolution rate and bioavailability. Microparticles of naproxen have been obtained by a Rapid Expansion of Supercritical Solutions (RESS) process in which carbon dioxide has been used as a solvent and methanol as a cosolvent. The influence of extraction pressure (200–300 bar) and extraction temperature (60 °C and 100 °C) on the naproxen precipitation has also been investigated. In general, the morphology of the precipitated particles improved and particle size (PS) decreased in comparison to the raw material. Lower extraction pressure and higher extraction temperature led to a smaller particle size. On the other hand, a supercritical antisolvent (SAS) process has been applied due to the relative medium solubility values of naproxen in supercritical carbon dioxide, with precipitation obtained successfully in all cases. The initial concentration of the solution and the solvent effect has both been analysed. Morphologies and mean diameter ranges have been analysed by scanning electron microscopy (SEM) and the influence on crystallinity of both supercritical processes has been evaluated by X-ray diffraction (XRD) measurements.     

Effects of supercritical CO2 extraction parameters on soybean oil yield

A series of operational parameters of supercritical fluid extraction of soybean oil (pressure: 300–500 bar, temperature: 40–60 °C, CO₂ mass flow rate: 0.194–0.436 kg/h and characteristic particle size: 0.238–1.059 mm) were investigated in a laboratory scale apparatus. The results show that the extraction yields were significantly affected by applied operational extraction parameters. The increase in pressure, temperature and solvent flow rate improved the extraction yield. The extraction yield increased as the particle size decreased depending on decreasing intra-particle diffusion resistance. To describe the extraction process Sovova's model was used and very good agreement with the experimental results was obtained. Based on the experimental data the internal and external mass transfer coefficients were estimated. To explore the influence of the extractor size on this process, soybean samples were extracted using different extraction basket volumes (0.2 L and 5 L) and related model parameters were examined. The mass transfer coefficient in the fluid phase increased with the increase in extractor size, while the mass transfer coefficient in the solid phase was independent of the extractor size.     

Fractionation of menhaden oil ethyl esters using supercritical fluid CO2

Supercritical fluid CO₂ was used to fractionate menhaden oil fatty acid ethyl esters to obtain concentrates of the esters of allcis-5,8,11,14,17-eicosapentaenoic acid (EPA) and allcis-4,7,10,13,16,19-docosahexaenoic acid (DHA). Separation of the ethyl esters was found to occur primarily by carbon number, thus limiting the degree to which the ethyl esters of EPA and DHA could be concentrated. Urea fractionation of whole esters in order to remove saturates, monoenes and dienes prior to fractionation with supercritical fluid CO₂ resulted in concentrates of EPA and DHA in purities exceeding 90%. Several criteria are given for the selection of crude oils in order to maximize both purity and yield of concentrates.     

Experimental and modelling of supercritical oil extraction from rapeseeds and sunflower seeds

The supercritical oil extraction from oleaginous seeds (sunflower and rapeseeds) is presented here through experimental and modelling results. The experimental setup allows an accurate following of the mass of the oil extracted and to derive the experimental influences of pressure, temperature and supercritical CO₂ flowrate on the extraction curves. These parameters are very sensitive and highlight the necessity of precise optimisation of experimental conditions. In order to complete the behaviour of supercritical fluids extraction, an improved modelling is proposed. The modelling basic equations are based on others modelling published previously. In this work, the determination of several parameters comes from correlations and the other constants are fitted with all the experimental results. Thus the modelling is more representative and predictive as other ones. The modelling results present a good agreement with the experimental results, and hence it can be used for the dimensioning of some extraction autoclaves.