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Grapeseed oil extracted by supercritical CO2 is more pure

Grapeseed oil

A large number of studies have confirmed that grapeseed contain 14% to 17% oil, of which 92% of unsaturated fatty acids,especially linoleic acid content of up to 76%; also contains vitamins A, D, E,K, P and so on. Grapeseed oil has the functions of clearing blood vesselcholesterol, preventing arteriosclerosis, anti-oxidation, nourishing braincells, regulating autonomic nerves, etc. It has a wide application prospect inthe food, medicine, chemical, cosmetics and other industries.

Supercritical fluid extraction technology

Supercritical fluid extraction technology usessupercritical fluid as solvent, using its good solubility and permeability, andby adjusting the temperature and pressure parameters of the system, thesolubility of the fluid in the supercritical state to the specific component issharply increased, thereby achieving a process of separating the mixture.

Supercritical CO2 fluid extraction

The CO2 critical temperature (31.06 ° C) and the critical pressure (7.38MP) are lower, and the extraction operation can be performed near roomtemperature, which reduces the thermal decomposition of the heat sensitivesubstance during the extraction process while reducing the requirements on theequipment and energy consumption.

Grapeseed oil extracted by supercritical CO2 is more pure
Grapeseed oil extracted by supercritical CO2 is more pure

At the same time, carbon dioxide isnon-flammable, non-toxic, environmentally friendly, inexpensive and easy toobtain, and is the most commonly used supercritical extraction solvent.

Supercritical CO2 extraction grape seed oil

Supercritical CO2 fluid extraction grapeseeds oil combines the advantages and functionsof liquid-liquid extraction and distillation, and overcomes the problem ofresidual organic solvents in traditional extraction methods.

Supercritical CO2 fluid extraction grapeseed oil only has its own technical advantages, but also can complete the degummingprocess, and partially play the role of deacidification, deodorization anddecolorization, greatly simplifying the subsequent process.

supercritical CO2 extraction of grapeseed oil

Grape seed oil supercritical CO2 extraction equipment
Grape seed oil supercritical CO2 extraction equipment

Method

  • Accurately weigh the pulverized, certain-grained grapeseeds in an extraction vessel at a volume of approximately 60% of thevolume of the kettle, then fix the extraction vessel in a heating furnace andclose the safety door.
    Ensure that the safety door does not open at will untilthe end of the extraction process.
    Check that each valve on the extractor isoff.
  • Connect the main power supply, constant temperaturecirculation system power supply and air compressor power supply separately tocheck whether the equipment is working properly.
  • Open the intake valve to allow liquid carbon dioxideto enter the extraction system through the siphon
  • Open the temperature control furnace and exhaustvalve temperature control switch respectively, and set the extractiontemperature and exhaust valve temperature on the temperature control panel.
  • After the kettle temperature reaches the set valueand stabilizes, adjust the system pressure to the set value. Keep the exhaustvalve closed and start the static extraction process.
  • After the static extraction is completed, the ventingvalve is opened to start the dynamic extraction process. Adjust the opening andclosing of the exhaust valve to control the air release rate of carbon dioxide.The supercritical fluid carrying the product expands throttling through thepressure reducing valve, releases the grapeseed oil and becomes normalpressure CO2 gas, and the venting flow rate is measured by the float flowmeter.
  • After the end of the extraction, the extract weight wasaccurately weighed, and the oil content of the grapeseed powder was measuredby a Soxhlet extractor, and then the extraction rate of the grapeseed oil wascalculated.
  • Extraction rate = G2/G1X1 × 100%
  • Among them: G1 – grapeseed powder quality (g); X1 -grapeseed powder oil content (%); G2 – extracted oil quality (g)

Factors affecting the extraction of grapeseed oil bysupercritical CO2 fluid

Effect of pulverization degree on grapeseed oilextraction

The particle size of the material has a dual effect onthe extraction.

On the one hand, the finer the material, the mass transfer areais increased, and the mass transfer distance and mass transfer resistance arereduced, which is beneficial to the extraction; on the other hand, if thematerial is too fine, it is easily compacted under high pressure, increasingthe mass transfer resistance without Conducive to extraction.

Due to the highcontent of grapeseed oil, it is generally easy to use about 40 mesh.

Effect of extraction intensity on grapeseed oilextraction

Supercritical CO2 fluids have good mass transfercharacteristics.

Increasing the pressure will not only increase the density ofCO2, but also reduce the distance between molecules.

At lower temperatures, theextraction rate of grapeseed oil gradually increases with increasing pressure,but when the pressure is too high, the extraction rate increases slowly.

Because of the high density of CO2 under high pressure, the compressibility issmall, and the increase of pressure has little effect on the solubility of thesubstance.

At the same time, high pressure will increase the investment andoperating costs of the equipment.
Therefore, it is more appropriate to select 28Mpa for extraction from all aspects.

Effect of extraction temperature on grapeseed oilextraction

On the one hand, the elevated temperature increases thediffusion coefficient of the substance, so that the solubility increases, whichis beneficial to the extraction; on the other hand, since the extractiontemperature is an important factor affecting the density of the supercritical CO2 fluid, when the temperature rises, the CO2 is lowered.

The density of thematerial reduces the solubility of the material, which is not conducive toextraction; in addition, the temperature rise will also reduce the quality ofthe product. Therefore, the extraction temperature should not be too high.

At 28Mpa, the extraction rate of grapeseed oil decreased with the increase of temperature, but the extraction rate increasedslowly at the specified temperature of 35 °C; when the pressure was less thanor equal to 28Mpa, the temperature was below 35 °C, and the extraction rateincreased with temperature. And rise. For the effect of combined pressure andtemperature, the optimum temperature for extraction should be 35 °C.

Effect of extraction time on grapeseed oil extraction

The supercritical CO2 fluid extraction process isdivided into three stages: the initial stage of extraction, the stage ofconversion, and the final stage of extraction.

In the initial stage of extraction,the contact time of the substance with CO2 is small, and the amount of materialper unit time is less; as the extraction time is extended, the extraction stageis gradually increased; the final stage of extraction is due to the low contentof the extracted material in the material. In addition, the amount ofextraction per unit time is reduced.

The results show that at 28 °C at 35 °C,the extraction rate is gradually increased below 80 minutes; the extractionrate below 80 minutes is close to the level and no longer increases. Therefore,the time for extracting grapeseed oil from supercritical CO2 fluid should be80 minutes.

Summary

In the technique of extracting grapeseed oil bysupercritical CO2 fluid, the pulverization degree extraction time temperatureis an important factor affecting the efficiency of extracting grapeseed oil.

Supercritical CO2 fluid extraction grapeseed oil combines the advantages and functionsof liquid-liquid extraction and distillation, and overcomes the problem ofresidual organic solvents in traditional extraction methods.

Supercritical CO2 fluid extraction grapeseed oil only has its own technical advantages, but also can complete the degummingprocess, and partially play the role of deacidification, deodorization anddecolorization, greatly simplifying the subsequent process.

Grapeseed oil extracted by supercritical CO2 is more pure.

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