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1.
This work uses a fully predictive mass transfer model to simulate the supercritical CO2 extraction of vegetable oils from prepressed oilseeds in the 1-m3 vessel of an industrial multi-vessel plant operating at 40 °C and 30 MPa with the purpose of minimizing the operational cost. The work analyses the effect of particle diameter (0.5, 1, 2, 3, and 4 mm), superficial CO2 velocity (2.76, 5.52, or 11.0 mm/s), and number of extraction vessels (2, 3, or 4) on optimal extraction time and minimal operational cost. Keeping other variables constants, cost diminishes as particle diameter decreases. Although the optimal superficial CO2 velocity increases as particle diameter decreases, in the case of small (≤1 mm) particles, substrate fluidization may place an upper limit to the superficial velocity. Within the studied region, best superficial CO2 velocities are 11.0 mm/s for particles smaller than 1–2 mm, 2.76 mm/s for particles larger than 3–4 mm, and 5.52 mm/s for particles in between. Keeping other variables constant, the cost of extraction of medium-to-large (≥2 mm) particles decreases as the number of extraction vessels increases, at the expense of an increase in extraction time. However, because of a sharp transition wave that develops when extracting small (≤1 mm) particles that separates fully extracted (downstream) from virtually unextracted (upstream) substrate within extraction vessels, two-vessel plants are best for small particles. The lowest operational cost observed in this work was USD 4.08 kg−1 oil for the extraction of 2-mm particles using 3.30 m3/h of CO2 (U = 2.76 mm/s) in a four-vessel plant.  相似文献   

2.
In this study, the essential oil of aerial parts of a species of a plant called Smyrnium cordifolium Boiss (SCB) was extracted by supercritical CO2. The essence was analyzed by the method of GC/MS. Design of experiments was carried out with response surface methodology by Minitab 16 software to optimize four operating variables of supercritical carbon dioxide (SC-CO2) extraction (pressure, temperature, CO2 flow rate and extraction dynamic time). This is the first report announcing optimization of the operation of supercritical extraction of SCB in laboratorial conditions. Optimizing process was done to achieve maximum yield extraction. Independent variables were dynamic time (td), pressure (P), temperature (T) and flow rate of SC-CO2 (Q) in the range of 30–150 min, 10–30 MPa, 40–60 °C and 0.5–1.7 ml/min, respectively. The experimental optimal recovery of essential oil (0.8431, w/w%) was obtained at 13.43 MPa, 40 °C, 150 min (dynamic) and 1.7 ml/min (CO2 flow rate).  相似文献   

3.
This work demonstrates that supercritical carbon dioxide extraction is efficient for the complete recovery of neutral lipids from microalgae with a water content up to 20 wt%, allowing thus a further full characterization of this oil. This is a first useful step in the framework of lipid production from microalgae either for nutraceutical, food or for energy applications. This study is particularly focused on the influence of the pretreatments upon extraction kinetics and yields. This study proposes a complete study at laboratory scale (10 g per batch of dry biomass) of the influence of pretreatments (type of drying and grinding) and of water content on the extraction kinetics and yields as well as on the oil composition in terms of lipidic classes and profiles. Two drying pretreatments (drying under air flow and freeze-drying) applied on Nannochloropsis oculata were studied. Extraction experiments were carried out at 40 MPa, 333 K, with a carbon dioxide flow rate of 0.5 kg h−1 and for different granulometries. Results showed that drying under air flow at 308 K is the most adequate pretreatment leading to the most rapid kinetics. Whatever the pretreatment used, the extracted oil contains more than 90 wt% of triglycerides and does not contain phospholipids. As expected, the smaller the particle size, the faster the extraction kinetics. Finally, an increase in the biomass water content up to 20 wt% increases the global extraction kinetics (extraction of both water and oil) but appears to have no influence on oil extraction yields. Moreover, the extraction of neutral lipids happens to be complete for a CO2/charge mass ratio ranging from 30 to 130 depending on the operating conditions and on the characteristics of the treated biomass. Finally, pilot scale experiments were performed with batches up to 15 kg in order to evaluate the influence of pressure and particle size on the extraction kinetics and yields. Extracts obtained at 333 K with operating pressures of 50 MPa and 85 MPa have similar compositions and do not contain phospholipids.  相似文献   

4.
Extraction of sunflower oil from sunflower seeds (Heliantus annuus L.) using supercritical CO2 was studied. The shrinking core model was applied to the modeling of the packed-bed extraction process. The experimental data were obtained for extraction conducted at the pressures of 20, 30, 40, 50 and 60 MPa; the temperatures of 313, 333 and 353 K, the CO2 flow rates of 1–4, and 6 cm3 CO2 min−1; the mean particle diameters of 0.23, 0.55, 1.09, 2.18 mm. The supercritical CO2 extraction process was modeled by a quasi steady state model as a function of extraction time, pressure, temperature, CO2 flow rate, and particle diameter. The supercritical CO2 extraction process. The intraparticle diffusion coefficient (effective diffusivity) De was used as adjustable parameter. The model using the best fit of De was correlated the data satisfactorily.  相似文献   

5.
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.  相似文献   

6.
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.  相似文献   

7.
The particle size of the pharmaceutical substances is important for their bioavailability (the percentage of the drug absorbed compared to its initial dosage). The absorption rate can be increased by reducing particle size of the drug particles. This study was conducted to investigate the effects of the extraction pressure (140–220 bar), extraction temperature (308–338 K), nozzle length (2–15 mm), effective nozzle diameter (450–1700 μm), and collection distance (1–10 cm) on the size and morphology of the precipitated ketoprofen particles. The characterization (size and morphology) of the particles was investigated using scanning electron microscopy (SEM). The average particle size of the original material was 115.42 μm, while the average particle size of the micronized particles is between 0.35 and 7.03 μm near to quisi-spherical, needle and irregular shape depending upon the experimental conditions.  相似文献   

8.
Pressed palm fiber (PPF), a residue obtained from palm oil industry, is a source of bioactive compounds, such as carotenoids, which are used as food additives. It also has cellulose and hemicellulose that can be used to yield fermentable sugars for the production of second generation ethanol. Supercritical fluid extraction (SFE) of pressed palm fiber provides an oil rich in carotenoids while subcritical water hydrolysis (SubWH) produces hydrolysates with high amounts of fermentable sugars. In this work, the effects of pressure (15–30 MPa) and temperature (318 and 328 K) on SFE of carotenoids were investigated. The SFE extract with highest carotenoid content was obtained at 318 K and 15 MPa (2.3% d.b., 0.81 mg β-carotene/g extract). After the extraction, the influence of process temperature (423–633 K), pressure (15 and 25 MPa), solvent:feed ratio (120 and 240), and residence time (1.25–5 min) on SubWH of the extraction residue was studied. At the temperature of 523 K, the highest total reducing sugar yield (11–23 g glucose/100 g carbohydrate) and the highest biomass conversion (40–97%) were obtained for any pressure and solvent:feed ratio. The highest selectivity for saccharide formation was found at 423 K (20–59 mol glucose/mol furfural equivalent). Optimal conditions for high saccharide formation and low sugar degradation product in subcritical hydrolysis were obtained at 523 K, 15 MPa, solvent:feed ratio of 120, residence time of 2.5 min with a total reducing sugar yield of 22.9 g glucose/100 g carbohydrate and a conversion of 84.9%.  相似文献   

9.
Utilization of supercritical CO2 in safflower seed extraction was performed using a semi-batch extractor. Different extraction parameters, such as 40–60 MPa pressure, 323–347 K temperature, 20–76 min time, and 1–3 mL/min CO2 flow rate were applied. A two-stage experimental design application was performed in order to maximize the oil yield. First of all, a 32 factorial design was applied to estimate the effect of the main factors and their interactions. The second part of the experimental design was improved and accelerated using the steepest ascent method. Optimum extraction parameters were determined to be 50 MPa pressure, 347 K temperature and 76 min time at a constant CO2 flow rate (3 mL/min) according to the 22 design. Under these conditions, the oil yield obtained was 39.42%, comparable with Soxhlet extraction (40%) for 8 h. Shrinking core and empirical kinetic models were applied in order to generalize the extraction process. The predicted data was compatible with the experimental data.  相似文献   

10.
Clove essential oil is an important product to food industry because it presents a powerful antioxidant and antimicrobial potential enabling its use for the substitution of synthetic commercial products for food preservation. The objective of this paper is to study the extraction kinetics for predicting operational condition to obtain Syzygium aromaticum essential oil using CO2 as solvent by means of the introduction of thermodynamic approach into the mathematical modeling of the process. Extractions were performed at 9000 kPa/313.15 K, 10,000 kPa/313.15 K, 9000 kPa/323.15 K, and 10,000 kPa/323.15 K and the essential oil yields obtained were 14.17%, 12.32%, 13.11%, and 14.02%, respectively. To calculate the extract solubility in CO2 supercritical, the Peng–Robinson EoS coupled with three mixing rules (van der Waals 1, van der Waals 2 and Mathias–Klotz–Prausnitz) was used and a mass transfer model was employed to represent the relationship yield versus extraction time. The mathematical modeling of the process using the calculated solubility presented high concordance with experimental data. The volatile extracts were analyzed by GC/MS and the major compounds were eugenol and β-caryophyllene. Also, minimum inhibitory concentration (MIC) of supercritical extracts was determined with respect to Escherichia coli, Staphylococcus aureus and Enterococcus faecalis by microdilution method. All samples inhibited the bacterial growth, being the extract obtained at 313.15 K/9000 kPa the most effective.  相似文献   

11.
Oil was extracted from the peach (Prunus persica) seeds by supercritical carbon dioxide. Principal phytosterols (stigmasterol, campesterol and β-sitosterol) that have been known to have cholesterol lowering properties were investigated in the extracted oil. Based on gas chromatography–mass spectrometry (GC–MS) analysis, β-sitosterol was identified in the peach seed oil. The effects of temperature, pressure, flow rate of supercritical CO2, mean particle size of the seeds and extraction time on the amounts of extracted oil and β-sitosterol were investigated. Supercritical fluid extractions were performed in a range of 35–55 °C, 160–240 bar, 4–8 ml CO2/min, 0.3–1.7 mm and 1–4 h for mentioned parameters. The results indicated that the amounts of oil and β-sitosterol extracted from the peach seeds were optimal with values of 35.3 g/100 g seed and 1220 mg/kg seed respectively at 40 °C, 200 bar, 7 ml/min, 0.3 mm and 3 h.  相似文献   

12.
The particle sizes of the pharmaceutical substances are important for their bioavailability. The bioavailability can be improved by reducing the particle size of the drug. In this study, salicylic acid and taxol were micronized by the rapid expansion of supercritical fluids (RESS). Supercritical CO2 and CO2 + ethanol mixture were used as solvent. Experiments were carried out to investigate the effect of extraction temperature (318–333 K) and pressure (15–25 MPa), pre-expansion temperature (353–413 K), expansion chamber temperature (273–293 K), spray distance (6–13 cm), co-solvent concentration (ethanol, 1, 2, 3, v/v, %) and nozzle configuration (capillary and orifice nozzle) on the size and morphology of the precipitated salicylic acid particles. For taxol, the effects of extraction pressure (25, 30, 35 MPa) and co-solvent concentration (ethanol, 2, 5, 7, v/v, %) were investigated. The characterization of the particles was determined by scanning electron microscopy (SEM), optical microscopy, and LC–MS analysis.The particle size of the original salicylic acid particles was L/D: 171/29–34/14 μm/μm. Depending upon the different experimental conditions, smaller particles (L/D: 15.73/4.06 μm/μm) were obtained. The particle size of taxol like white crystal powders was reduced from 0.6–17 μm to 0.3–1.7 μm The results showed that the size of the precipitated salicylic acid and taxol particles were smaller than that of original particles and RESS parameters affect the particle size.  相似文献   

13.
Feverfew (Tanacetum parthenium L., Asteraceae) is a perennial medicinal plant which has been used to alleviate the symptoms of migraines, headaches and rheumatoid arthritis. The herb contains various potentially active constituents such as sesquiterpene-γ-lactones, flavonoids and volatile oil. The main sesquiterpene-lactone in feverfew is parthenolide which is considered to be responsible for the therapeutical effects. Supercritical CO2 extraction was carried out at different pressures (10–30 MPa), temperatures (40–80 °C) and co-solvent contents (0–10% ethanol) in order to study the extraction yield and the parthenolide recovery of the extracts. Leaves collected before and during flowering and flower heads were investigated. A factorial experiment using a full 33 design was followed during the experiments and response surface methodology was implemented to analyze the influence of the variables and optimize the extraction. The critical values of parthenolide content were found to be 7% EtOH, 22 MPa and 64 °C in case of all three samples. It was determined, that the optimal conditions of the extraction, where the maximum parthenolide content and extract yield can be reached, do not coincide. The highest yield of parthenolide was obtained in the flower heads (0.604 wt.%).  相似文献   

14.
Carob pulp kibbles, a by-product of carob been gum production, was studied as a source of bioactive agents. Firstly, the carob kibbles were submitted to an aqueous extraction to extract sugars, and supercritical fluid extraction (SFE) was applied to the solid residue of that aqueous extraction, by using compressed carbon dioxide (SC-CO2) as the solvent and a mixture of ethanol and water (80:20, v/v) as a co-solvent. Pressure and temperature were studied in the ranges 15–22 MPa, and 40–70 °C. Particle diameter, and co-solvent percentage in ranges of 0.27–1.07 mm, and 0–12.4%, respectively, were also studied, as well as the flow rate of SC-CO2 between 0.28 and 0.85 kg h−1, corresponding, respectively, to 0.0062 and 0.0210 cm s−1 of superficial velocity. The extracts were characterised in terms of antioxidant capacity by DPPH method, and total phenolics content by the Folin–Ciocalteu method. The central composite non-factorial design was used to optimise the extraction conditions, using the Statistica, version 6 software (Statsoft). The best results, in terms of yield and antioxidant capacity, were found at 22 MPa, 40 °C, 0.27 mm particle size, about 12.4% of co-solvent and a flow rate of 0.29 kg h−1 of SC-CO2. The phenolics profile of the extracts obtained at these conditions was qualitatively evaluated by HPLC-DAD. The solid residue of the supercritical extraction was also studied showing to be a dietary fiber, which can be compared to Caromax™, a carob fiber commercialised by Nutrinova Inc.  相似文献   

15.
A pharmacological active component, mangiferin, was extracted from Mahkota Dewa using subcritical water extraction. The subcritical water extractions were carried out at temperatures ranging 323–423 K, pressures ranging 0.7–4.0 MPa, and extraction times ranging 1–7 h. Extraction yield of mangiferin was measured using high-performance liquid chromatography (HPLC). The extraction yield was strongly dependent on the temperature while weakly dependent on the extraction pressure. As the extraction temperature increased, the extraction mangiferin yield increased, possibly resulting from the decrease in polarity of subcritical water at higher temperature. At an optimal extraction condition of 373 K, 4.0 MPa and extraction time of 5 h, the extraction yield of mangiferin was 21.7 mg/g. This value was close to the extraction yield with methanol (25.0 mg/g) and higher than those with water (18.6 mg/g) or ethanol (13.2 mg/g) at their boiling points.  相似文献   

16.
Supercritical carbon dioxide extraction of Gac (Momordica cochinchinensis Spreng) aril was performed at pressures ranging from 200 to 400 bar, temperatures from 313 to 343 K and specific flow rates from 50 to 90 kg h−1 CO2 kg−1 Gac aril. Total oil recovery and carotenes concentration were investigated in the course of extraction. Mathematical modelling of oil solubility data was also performed. The results showed that at specific flow rate of 70 kg h−1 kg−1, pressure of 400 bar and temperature of 343 K, Gac oil recovery exceeded 95% after 120 min of extraction. Gac oil loading of supercritical carbon dioxide was successfully described by Chrastil's model. Carotenes concentration of extracted Gac oil was found at level of thousands of ppm.  相似文献   

17.
Supercritical carbon dioxide (SC-CO2) and soxhlet extraction using was carried out to extract oil from wheat bran oil. For SC-CO2, the pressure and temperature were ranging from 10 to 30 MPa and 313.15–333.15 K. The extraction was performed in a semi batch process with a CO2 flow rate of 26.81 g/min for 2 h. Wheat bran oil was characterized to investigate the quality. Acid value (AV) and peroxide value (POV) were higher in hexane extracted oil compared to SC-CO2 extracted oil. Induction period was measured by rancimat test. The oil obtained by SC-CO2 extraction had higher capability to delay the oxidation by surrounding environment. The DPPH radical scavenging activity was also measured. The SC-CO2 extracted oil showed higher radical scavenging activity compared to hexane extracted oil.  相似文献   

18.
In this paper, we propose a new methodology for recovering silicon from silicon sludge using supercritical water in a semi-batch reactor. Silicon sludge is the waste discharged from the silicon ingot cutting process and consists of cutting oil, cooling water, and silicon particles. The oil contained in silicon sludge was removed completely within several minutes by supercritical water elutriation at 400 or 500 °C and 25 MPa. The recovery percentage of silicon was only 70% at 400 °C owing to silicon dissolution. However, the recovery percentage was greater at a higher temperature (95% at 500 °C) because silicon dissolution was suppressed owing to the low ion product of water at higher temperatures. The silicon recovered at 500 °C and 25 MPa was approximately 99.2% pure. Contamination by oxidation was negligible because an oxide film did not grow on the silicon surface during the supercritical water treatment. We conclude that high-purity silicon can be recovered efficiently by supercritical water elutriation using a semi-batch reactor and that the methodology is promising for recovery of silicon from silicon sludge.  相似文献   

19.
In this work different samples of Brazilian macauba oil obtained from mechanical pressing were characterized and production of esters of fatty acids using a catalyst-free continuous process under supercritical alcohols was assessed. Analysis of oil samples showed that the major fatty acid on pulp oil was oleic acid (mean value 62.8%), the amount of free fatty acid (FFA) was very high (37.4–65.4%), samples contained glycerides (7.4–16.5% TAG, 14.2–16.8% DAG and 1.0–3.4% MAG) and moisture was around 1.0%. Oil was processed in a continuous reactor using supercritical methanol or ethanol and the effects of temperature (573, 598, 623 and 648 K), pressure (10, 15 and 20 MPa), oil to alcohol molar ratio (1:20, 1:30 and 1:40), water concentration (0, 5 and 10 wt% added) and the flow rate of reaction mixture (1.0, 1.5, 2.0, 2.5 and 3.0 mL/min) on process efficiency were evaluated. The highest ester content achieved in reactions with supercritical methanol was 78.5% (648 K, 15 MPa, 1:30 oil:methanol molar ratio, 5 wt% water and 2.5 mL/min flow rate), while with supercritical ethanol was 69.6% (598 K, 15 MPa, 1:30 oil:ethanol molar ratio, 5 wt% water and 2.0 mL/min flow rate). The extent of the reaction was explored using a novel parameter, convertibility, which corresponds to the maximum ester content attainable from the feedstock. According to the convertibility of macauba pulp oil, the highest ester content corresponded to efficiencies of 98.0% and 86.9%, respectively. Results demonstrate that macauba oil might be a potential alternative for biodiesel production, though purification steps should be taken into account to achieve biodiesel specifications.  相似文献   

20.
Lecithin was isolated from squid viscera residues after supercritical carbon dioxide (SC-CO2) extraction at 25 MPa and 45 °C. The particle formation of squid lecithin with biodegradable polymer, polyethylene glycol (PEG) was performed by PGSS using SC-CO2 in a thermostatted stirred vessel. By applying different temperatures (40 and 50 °C) and pressures (20–30 MPa), conditions were optimized. Two nozzles of different diameters (250 and 300 μm) were used for PGSS and the reaction time was 1 h. The average diameter of the particles obtained by PGSS at different conditions was about 0.74–1.62 μm. The lowest average size of lecithin particle with PEG was found by the highest SC-CO2 density conditions with the stirring speed of 400 rpm and nozzle size of 250 μm. The inclusion of lecithin in PEG was quantified by HPLC. Acid value and peroxide value was measured after micronization of lecithin.  相似文献   

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