Modeling Of Supercritical Fluid Extraction Research Articles

Phenomenological modeling of supercritical fluid extraction of oil from Elaeagnus angustifolia seeds

This research addressed the supercritical CO2 (sc-CO2) extraction of Elaeagnus angustifolia oil and its mathematical modeling. After experimental sc-CO2 extraction, the process was modeled based on mass transfer equations. Design of experiments and optimization were accomplished by Box-Behnken design to analyze the effects of the main operational parameters including pressure (20–30 MPa), temperature (313–333 K), and particle size (0.30–1.20 mm). Then, correlation of experimental extraction data with mathematical models was performed. The tunable parameters of the models were obtained by Genetic algorithm (GA) optimization. The model results were compared with experimental findings based on the average absolute relative deviation. The highest extraction yield (84.9% w/w) was achieved at the optimum conditions involving the pressure, temperature, and particle size of 30 MPa, 323 K, and 0.30 mm, respectively.The results obtained from the analysis of variance (ANOVA) indicated high and acceptable accuracy of mathematical models for the supercritical extraction process.

Recovery of biologically active compounds from stinging nettle leaves part I: Supercritical carbon dioxide extraction

Stinging nettle is annual plant from Urticaceae family used as food and medicine. Due to the nonsufficient data, this work aimed to isolate the bioactive compounds from the stinging nettle leaves by supercritical carbon dioxide. Extracts were analyzed and assessed for antioxidant and cytotoxic activities. Main fatty acids were α-linolenic (31.06–58.42 mg/g E), palmitic (9.17–13.12 mg/g E), and linoleic (10.93–16.51 mg/g E) acids. Chlorophylls (33.00–7365.11 mg/100 g E) and carotenoids (166.88–722.62 mg/100 g E) were also found in all samples. Four empirical kinetic equations were effectively utilized for kinetic modeling of supercritical fluid extraction. As per proper statistical features, empirical models show good concurrence with experimental data. The numerical modeling of a process is gainful to foresee the process conduct and furthermore extend the methodology from laboratory to industrial scales. The principal component analysis was used to visualize the fatty acids profile, antioxidant capacity, and cytotoxic activity of extract.

Experimental Optimization and Modeling of Supercritical Fluid Extraction of Oil from Pinus gerardiana

AbstractThe influence of different temperatures, pressures, and flow rates on the supercritical fluid extraction (SFE) of oil from Pinus gerardiana was investigated. Extraction was designed using the Box‐Behnken design and artificial neural network. Furthermore, a mathematical model of broken and intact cells was applied to consider mass transfer kinetics of extracted natural materials. The experimental oil extraction was performed by Soxhlet and supercritical carbon dioxide methods and the yield and composition of the obtained oils was compared. Although the yield of the SFE process was lower than that of the Soxhlet extraction, the SFE presented the advantage of shorter extraction time and lower temperatures. Also, the chemical compositions of the obtained oils from Soxhlet and SFE processes were the same.

Modeling of supercritical fluid extraction by enhancement factor of cosolvent mixtures

ABSTRACT In this study, Sovová mass transfer-based mathematical model for supercritical fluid extraction was modified by incorporating a cosolvent enhancement factor. Modeling of supercritical carbon dioxide with different cosolvent mixtures was successfully performed in the extraction of model plants (Phyllanthus niruri and Polygonum minus) with an average absolute relative deviation (AARD) of less than 7.90%. The existence of non-typical extraction curves in SCO2 with alcohol–water cosolvent was also well fitted and predicted by the modified model. In the extraction of both plants, internal mass transfer was found to be the rate-limiting factor in the first phase of extraction, namely pre-extraction. Abbreviations: A: surface area; ɛ: porosity; dp : particle size or size distribution; D: vessel diameter; EC : enhancement factor; EC,V : enhancement factor in vapor phase; EC,L: enhancement factor in liquid phase; f: total solvent flow rate; H: height; kXa: mass transfer coefficient in solid phase; kYa : mass transfer coefficient in fluid phase; mt : mass of extract; MCER : global extraction yield at constant extraction rate; N: mass of the inert solid; : moles of solvent without cosolvent; : moles of solvent with cosolvent; : total solvent moles without cosolvent; : total solvent moles with cosolvent; P: pressure; Qf : solvent mass flow rate; Sij : selectivity; t: extraction time; T: temperature; tCER : the end of the first extraction period; tFER : the end of the second extraction period; U: solvent superficial velocity; W: model parameter related to the diffusion in solid phase; xi, xj : solvent mole fraction in liquid phase; Xk : mass of hardly accessible solute; Xo : initial mass of extractable material; Xp : ratio of extractable material at particle surface in solid phase; yi, yj : solvent mole fraction in vapor phase; : mole fraction of pure governing solvent; : mole fraction of the solvent in the cosolvent mixtures; Y*: solute solubility in the solvent; YCER : solubility at constant extraction rate; Z: model parameter related to convection in the fluid phase; zw : parameter of the second extraction period; ρf : solvent density; ρs : sample density; μ: viscosity.

Selection of suitable model for the supercritical fluid extraction of carrot seed oil: A parametric study

To investigate suitable model for supercritical fluid extraction of carrot seed oil, different mathematical models are selected from literature and solved using COMSOL Multiphysics software. Operating parameters such as pressure, temperature, solvent flow rate, and addition of co-solvent are varied in ranges as 200–400 bar, 50–70 °C, 5–15 g/min, and 0–10 wt%, respectively. Solvent and solid phase mass transfer coefficients, easily accessible oil content and equilibrium constant are considered as tuning parameters to fit the model with experimental data. Oil yield is increased with pressure (400 bar) and temperature (70 °C) whereas, its value is highest at the solvent flow rate of 10 g/min, and co-solvent of 5 wt%. Thus, these values of parameters are considered as optimum points.

Development of generalized and simplified models for supercritical fluid extraction: Case study of papaya (Carica papaya) seed oil

The present study described the experimentation and modeling of supercritical CO2 extraction (SCE) process for papaya seed oil. Experiments were performed at various ranges of SCE parameters; temperature (303.15–368.15)K, pressure (15–35)MPa, solvent flow rate (5–25)g/min, particle size (0.2–1.4)mm and co-solvent (ethanol) flow rate as (0–20)% of CO2 flow rate. Obtained oil was analyzed through gas chromatography to estimate fatty acid concentrations. Effects of SCE parameters were investigated on the extraction yield and oleic acid concentration of papaya seed oil through central composite design. Further, two mathematical models (PM-1 and PM-2) were developed based on desorption–diffusion–dissolution (PM-1) and broken and intact cell (PM-2) mechanisms. These models were validated with the experimental data of papaya seed oil and further compared with the existing models. PM-1 proposed an equilibrium relation while assuming saturation of solvent and solute at interphase, which was successfully validated with the experimental data in the AARD range from 0.40% to 32.48%. PM-2 reduced the three zones of extraction curves to two and better fitted the experimental data of papaya seed in the AARD range from 0.45% to 35.62%. Model parameters of PM-2 were optimized through genetic algorithm.

Extraction kinetics modeling of wheat germ oil supercritical fluid extraction

The aim of this study was the optimization of supercritical fluid extraction (SFE) of wheat germ oil obtained as by-product from industrial mill. Extraction kinetics modeling and response surface methodology (RSM) were used for that purpose. SFE was performed with broadening Box-Behnken experimental design, where pressure (250–350 bar), temperature (40–60°C), and CO2 flow rate (0.2–0.4 kg/hr) were used as independent variables. Five empirical kinetic equations were successfully utilized for modeling of SFE. Model IV (Kandiah and Spiro model) provided the best fit with experimental data, according to statistical parameters (R2, sum of squared errors and average absolute relative deviation). Furthermore, initial slope calculated from this model was used as a response variable for RSM optimization. It could be concluded that SFE should be performed at elevated pressure (350 bar) and CO2 flow rate (0.4 kg/hr), while temperature should be held at a lower level (40°C) in order to achieve a maximal initial slope. Practical applications Optimization and modeling of industrial processes are crucial factors that will determine its efficiency and profitability. This research provided information about modeling of green and environmentally friendly extraction technique, that is, SFE, which could be successfully utilized for recovery of valuable oil from food industry by-product, that is, wheat germ. Commonly used empirical models were successfully applied for modeling of extraction process and influence of SFE factors on model parameters was determined providing information about mass transfer phenomena during extraction. Further investigation provided determination of the highest initial extraction rate constant which could be applicable for optimization of industrial scale processes.

Solubility modeling of supercritical fluid extraction in a wide range compounds: comparison between fuzzy-genetic and new empirical models

ABSTRACTIn the current study, two methods based on a new empirical equation and fuzzy-genetic model are proposed to estimate solute solubility in supercritical fluid (SCF). New proposed models are trained with comprehensive dataset collected from literature with more than 3,260 experimental data at different temperature and pressure. In order to testify the accuracy, the proposed models are compared to other empirical equations. The amounts of average values of absolute relative deviation ()were obtained 7.74% for fuzzy-genetic model and 9.27% for new proposed empirical model. The reasonable accuracy of developed models for estimating the solubility of solutes in SCF extraction process is represented. From literature solubility data, the authors obtained new estimation models for solute solubility in CO2 supercritical which are in agreement with measured experimental values.

Extraction yield and kinetic study of Lippia graveolens with supercritical CO2

In this study, leave extracts of Lippia graveolens were obtained using supercritical CO2. The objective was to evaluate the effect of temperature and pressure on the extraction yield and kinetics. Supercritical fluid extractions were performed at three pressures (13, 15 and 35 MPa) and two temperatures (40 and 60 °C). Sovová’s model for supercritical fluid extraction was fitted to describe the kinetic extraction curves and analyze the results. The extracts were analyzed by GC–MS, where Carvacrol was the majority compound in all the experiments. A maximum yield of 2.6% on a dry weight basis was obtained at 35 MPa and 60 °C. The extraction yield increased with temperature and pressure, in all the analyzed samples.

Kinetic Modeling of Supercritical Fluid Extraction of Betel Nut

Supercritical fluid extraction is an advanced extraction technique that suitable for heat sensitive and active compound material from plants and herbs. Understanding the effect of extraction parameters on mass transfer coefficient at solid and fluid phase can determine the dominating extraction regime thus performance of the extraction may be enhanced. The aim of this research was to determine the mass transfer coefficient in solid and fluid phase using kinetic modelling approach. Grounded betel nuts were treated with supercritical carbon dioxide with 5% methanol as co-solvent to determine its mass transfer coefficient in solid and fluid phase for the following extraction conditions; pressure, 20 to 30 MPa; temperature, 50 to 70 °C; and flow rate, 2 to 4 mL/min. Simplified Sovova model was coupled with Broken and Intact Cell model to determine the mass transfer coefficients. Results show the mass transfer coefficients of solid phase and liquid phase are in the ranges of 0.00015 to 0.00353 m3/min and 0.3497 to 3.9623 m3/min, respectively. The overall absolute average relative deviation was observed to be 7.39%.

Multicomponent inverse modeling of supercritical fluid extraction of carotenoids, chlorophyll A, ergosterol and lipids from microalgae

The fundamentals of analyte extractable fraction, solubility, partitioning and mass transfer resistance in supercritical fluid extraction were studied using inverse modeling. These phenomena are essential for understanding, predicting and optimizing the supercritical fluid extraction process. Carotenoids, chlorophyll A, ergosterol and total lipids were extracted from the microalgae Chlorella sp. The analytes were measured continuously in-line and on-line using UV/Vis absorption spectroscopy measurements and by evaporative light scattering detection. Various pressures, temperatures, flow rates and fractions of ethanol as a co-solvent were evaluated. The extractable fraction of carotenoids, chlorophyll A and total lipids were dependent on the co-solvent fraction in the extraction phase. The additional amount that could be extracted by using more co-solvent followed a normal distribution, indicating that analytes should not simply be categorized into weakly or strongly bound. The characteristics of diminishing extraction rates over time was accounted for by analyte partitioning rather than intra-particle diffusion limitations.

Estimation of the Axial Dispersion Effect on Supercritical Fluid Extraction from Bidisperse Packed Beds

The general hydrodynamic equations of a mathematical model for supercritical fluid extraction are derived within the framework of the continuum mechanics approach. The shrinking core concept is used to describe the mass transfer on the solid-liquid interface. The complete system of macroscopic differential mass-balance equations is reduced to a one-dimensional approximation and accounts for the axial dispersion effect. Correlation formulas available in the literature are used to calculate the axial dispersion coefficient for the conditions of supercritical CO2 filtration. The effect of axial dispersion on the characteristics of the macroscopic process is analyzed for the typical laboratory-scale extraction conditions in the framework of the suggested model. The numerical simulations demonstrate that the difference between the values of the current mass of accumulated extract calculated in terms of the complete approach, which accounts for the axial dispersion, and the one related to the simplified model (in which the axial dispersion is neglected), is less than 10%. The same comparison is made for the outlet concentrations of the target compounds; the difference reaches 200%.

Kinetics model for supercritical fluid extraction with variable mass transport

This paper studies supercritical fluid extraction in which we take the effects of solute concentration variation on mass transport into account. A kinetics model with variable mass transfer coefficients proposed to describe supercritical fluid extraction of grape and almond seed oil. Threedistinctstages are found for extraction process, i.e., fast-extraction, slow-extraction, transition period, with a very short overflowoil in first stage. The overflow oil period is so short and the concentration variation is so slight that we think this period belongs to the fast-extraction stage. Theoretical predictions for yield distributions of supercritical fluid extractionare highly in agreement with the experimental data in literatures, which implies that the proposed model can be used to predict more mechanism for the extraction process. Moreover,the effects of involved parameters on mass transport and supercritical extraction process are shown graphically and analyzed.

Broken-and-intact cell model for supercritical fluid extraction: Its origin and limits

One group of mathematical models for supercritical fluid extraction from plants is based on the Broken-and-Intact Cell (BIC) concept. A simplified BIC model with analytical solution, derived for the extraction of vegetable oils from seeds, was published in 1994. It has been used by several researchers also for the extraction of other solutes from other plant parts. The aim of this contribution is to show how the simplified BIC model was derived from Lack’s model, for what type of extractions it is suited and where it fails, and how the BIC models have been improved since then.

Bidisperse Shrinking Core Model for Supercritical Fluid Extraction

AbstractThe broken‐and‐intact‐cell model is conventionally used for interpretation of overall extraction curves (OECs) observed in supercritical fluid extraction (SFE) of ground oilseeds. Another possibility, considered here, assumes that the packed beds of the ground material always contain a significant amount of very small particles, i.e., dust, which control the initial extraction rates. The bidisperse representation of particle ensembles allows accurate description of OECs on the basis of the modified shrinking core model. A simple asymptotic solution has been derived for bidisperse granulometric distributions under typical SFE conditions. Special microscopic observations have been performed to reveal and examine the dust fraction in ground seed substrates.

Evaluation of models for supercritical fluid extraction

Various models available in the literature for the modeling of supercritical extraction process are studied and validated using published experimental data. The first model considers internal mass transfer coefficient as the controlling parameter for the extraction process. On the other hand, the second model analyzes the dynamic behavior of the extraction process by considering intra-particle diffusion and external mass transfer. These models have also been studied to understand the effects of various model parameters like intra-particle diffusion, mass transfer coefficients & operating parameters on cumulative extraction yield. The model proposed by Reverchon (1996) [13] predicts a cumulative yield within an error limit of +9% in the MATLAB simulation and +4% to −5% in the FEMLAB simulation. Also, the model proposed by Goto et al. (1993) [8] fits the experimental data of Kim et al. (2007) [19], Skerget and Knez (2001) [20], and Tonthubthimthong et al. (2004) [21] within an error band of +10% to −2%.

Modeling of supercritical fluid extraction of flavonoids from Calycopteris floribunda leaves

AbstractThe aim of this study was to obtain flavonoids extracts from Calycopteris floribunda leaves using supercritical fluid extraction (SFE) with CO2 and a co-solvent. Pachypodol, a potential anticancer drug lead compound separated from the extracts, was examined. Classical organic solvent extraction (CE) with ethanol was performed to evaluate the high pressure method. HPLC analysis was introduced to interpret the differences between SFE and CE extracts in terms of antioxidant activity and the concentration of pachypodol. SFE kinetics and mathematical modeling of the overall extraction curves (OEC) were investigated. Evaluation of the models against experimental data showed that the Sovová model performs the best. The supercritical fluid extraction process was optimized using a central composite design (CCD), where temperature and pressure were adjusted. The optimal conditions of SFE were: pressure of 30 MPa and temperature of 35°C.

Mathematical modeling of supercritical fluid extraction of oil from canola and sesame seeds

Mathematical modeling of supercritical fluid extraction of oil from canola and sesame seeds with a two-phase model was performed in this work. A model based on differential mass balance was used to correlate the experimental data. Different adsorption isotherm models (Henry, Freundlich and Brunauer, Emmet and Teller (BET)) were used to describe the equilibrium state. Three model parameters such as effective diffusivity (Deff), mass transfer coefficient (Kf) and axial dispersion coefficient (Dax) of the bed were used as fitting parameters. The experimental data for yields were obtained at pressures of 10-20 MPa, temperatures of 313-333 K and solvent flow rates of 2-4 g/min. From the results, a nonlinear adsorption isotherm exhibited better agreement with experimental data of yield than a linear model in the range of studied conditions.

Steps of supercritical fluid extraction of natural products and their characteristic times

Kinetics of supercritical fluid extraction (SFE) from plants is variable due to different micro-structure of plants and their parts, different properties of extracted substances and solvents, and different flow patterns in the extractor. Variety of published mathematical models for SFE of natural products corresponds to this diversification. This study presents simplified equations of extraction curves in terms of characteristic times of four single extraction steps: internal diffusion, external mass transfer, hypothetic equilibrium extraction without mass transfer resistance, and displacement of the solution from the extractor. Preliminary evaluation of experimental extraction curves using these equations facilitates the choice of proper detailed model for SFE and enables estimation of changes in the extraction kinetics with the changes in operation conditions and extraction geometry.

Review of kinetic models for supercritical fluid extraction

The supercritical fluid extraction (SFE) of liquids and solid materials is gaining increasing interest and commercial application in last decades, most particularly under the recent concept of green chemistry and biorefinery. Hence, it is fundamental to provide adequate modeling of the SFE, in order to optimize operating conditions and simulate the global process. This work intends to review the most significant and physically sound models published in the literature for countercurrent liquid-supercritical fluid extraction and SFE of solid matrices, such as the linear driving force, shrinking core, broken and intact cells, and the combination of BIC and shrinking core models. The main assumptions and mass transfer expressions are presented and discussed.