supercritical co2 extraction machine

Study on supercritical CO2 extraction of millet bran oil

The best parameters for extracting millet bran oil using a supercritical co2 extraction machine:

Moisture content:8%

Extraction pressure:30Mpa

Extraction temperature:45 °C

Extraction time:240 minutes

Extraction efficiency19.69%

Summary

Under the condition of 50 kg/h CO2 flow rate, the orthogonal test of three factors and three levels was carried out for extraction pressure, extraction temperature and extraction time. Based on the results of single factor test and orthogonal test, when the pressure was 35 MPa, the oil quality was relatively turbid, and the equipment investment, power consumption and risk were large. The final conditions for supercritical CO2 extraction of millet bran oil are: extraction pressure 30 MPa, extraction temperature 45 ℃, extraction time 2 h, CO2 flow rate 50 kg/h. Under the optimum conditions, the yield of millet bran crude oil can reach 19.69%.

Content:

Millet bran is a by-product of husking millet into refined millet, which is rich in many nutrients. The oil content of millet bran is as high as 15% - 20%, which can be used to extract millet bran oil. Millet bran oil is a kind of healthy oil. The proportion of fatty acids in Millet bran oil is more in line with the nutritional requirements than the common edible oil. The content of unsaturated fatty acids accounts for more than 70%, especially the most important essential fatty acids and linoleic acids in human body. Linoleic acid is one of the essential fatty acids for human body. It is indispensable but not synthesized by human body itself. It has many physiological effects on human body. Especially, it participates in the synthesis of phospholipids and takes the form of phospholipids as an important component of mitochondria and cell membrane. It can also promote the metabolism of cholesterol and lipids, reduce cholesterol and prevent atherosclerosis. It can also synthesize prostaglandins Prostaglandins can dilate and contract blood vessels, conduct nerve stimulation, and protect skin from damage caused by radiation.

supercritical CO2 fluid extraction machine
supercritical CO2 fluid extraction machine

Millet bran oil also has the effect of dispelling wind, relieving itching and astringent, so millet bran oil is a kind of oil with high nutritional value and added value, which can be widely used in medicine, health care products, cosmetics and other industries in addition to consumption. China has rich millet bran resources, with an annual output of more than 2 million tons of millet and more than 100000 tons of bran. The development of millet bran resources can not only effectively use agricultural waste resources, but also promote farmers to become rich and improve people's living standards. At present, there are few studies on the extraction technology of millet bran oil in China, and the extraction methods similar to rice bran oil mainly include pressing, organic solvent extraction, electric heating and supercritical extraction. Devittori et al.studied the extraction of millet bran oil by supercritical extraction technology. They investigated the operating conditions of supercritical extraction and compared it with petroleum ether extraction method. The results showed that the indexes of fatty acids, free fatty acids and tocopherols extracted by the two methods were basically the same, but there were still some impurities in the products of supercritical fluid extraction.

 

In this study, the extraction of millet bran oil from rice bran by supercritical CO2 extraction distillation technology can not only improve the yield of the product, directly obtain essential oil products, but also have no solvent residue, which can retain the activity of the nutrients in it to the maximum extent. This technology is a new type of green technology, which can relieve the pressure of industrial production on the environment.

 

CO2 extraction system

CO2 extraction equipment
supercritical CO2 fluid extraction machine

Process I: raw material → drying → grinding → weighing → supercritical extraction → millet bran crude oil.

Process II: millet bran crude oil → weighing mass → loading and sealing → supercritical distillation → millet bran essential oil.

 

Supercritical CO2 extraction of millet bran crude oil

The dried rice bran was crushed, the rice bran of certain mass was weighed accurately and put into the extraction kettle. The supercritical CO2 extraction equipment was started. The influence of extraction pressure, extraction temperature, extraction time and CO2 flow rate on the extraction effect was investigated by single factor and orthogonal test.

 

Factors affecting supercritical CO2 extraction:

Effect of extraction pressure on oil yield of millet bran

When the extraction temperature is fixed, the extraction pressure increases, the density of the fluid increases, the strength of the solvent increases, and the solubility of the solute increases, which is conducive to extraction. It can be seen from Figure 1 that under the extraction temperature of 45 ℃ and extraction time of 2h, with the increase of extraction pressure, the oil yield of millet bran oil increases gradually, but when the pressure is greater than 35MPa, the oil yield increases slowly and the oil quality is turbid. If the operating pressure is too high, the equipment investment and power consumption will increase, and the risk will increase. The extraction pressure is 35 MPa.

 

Effect of extraction temperature on oil yield of millet bran

The influence of extraction temperature on the solubility of supercritical fluid is complex. At a certain pressure, when the temperature is raised, the volatility of the extracted substance increases, so the concentration of the extracted substance in supercritical gas is increased, so that the extraction quantity is increased; on the other hand, when the temperature is raised, the density of supercritical fluid is reduced, and its solubility is correspondingly decreased, leading to the reduction of the extraction quantity. Therefore, we should take these two factors into consideration. In this study, the influence of temperature under different extraction pressure on the oil yield of millet bran oil was investigated respectively. According to Fig. 2 (extraction time 1H), when the extraction temperature is lower than 45 ℃, the oil yield increases with the increase of temperature; when the extraction temperature is higher than 45 ℃, the oil yield decreases slightly with the increase of temperature, so the extraction temperature is determined as 45 ℃.

 

Effect of extraction time on oil yield of millet bran

As the extraction process is a dynamic mass transfer process, in the initial stage of extraction, the longer the contact time between supercritical fluid and solute is, the better the solution balance between supercritical fluid and effective components is, and the longer the extraction time is, the higher the oil yield will be. In the last stage of extraction, the oil yield increases slowly with the decrease of effective components and the increase of extraction time. With the extension of time, the energy consumption of supercritical fluid extraction is also increasing, and more invalid components are extracted, which directly affects the final quality of the product. In this study, the influence of extraction time on the oil yield of millet bran oil was investigated respectively. It can be seen from Fig. 3 (extraction pressure 35MPa, extraction temperature 45 ℃), when the extraction time is less than 2h, the oil yield will increase with the increase of extraction time; when the extraction time is more than 2h, the oil yield will increase slowly with the increase of extraction time, so it is appropriate to select 2H as the extraction time.

 

Effect of CO2 flow rate on oil yield of millet bran

The change of CO2 flow rate has two effects on supercritical extraction. One is to increase the flow rate of supercritical fluid, reduce the residence time of fluid in the extractor, reduce the contact time of fluid and solute, and reduce the extraction rate; on the other hand, with the increase of fluid flow rate, increase the collision between solute and supercritical CO2 molecules, strengthen the mass transfer, and improve the extraction rate and extraction rate. Therefore, the flow of CO2 should not be too large or too small, and the appropriate flow should be considered comprehensively. In this study, the effect of different CO2 flow rates on the oil yield of millet bran oil is investigated. It can be seen from Figure 4 (extraction pressure 35MPa, extraction temperature 45 ℃, extraction time 2H). When the CO2 flow rate is less than 50kg / h, the oil yield increases with the increase of CO2 flow rate; when the CO2 flow rate is greater than 50kg / h, the oil yield decreases with the increase of CO2 flow rate, so 50kg / h is the best choice for CO2 flow rate.

 

Orthogonal test of extracting crude oil from millet bran

Under the condition of 50 kg/h CO2 flow rate, the orthogonal test of three factors and three levels was carried out for extraction pressure, extraction temperature and extraction time. Based on the results of single factor test and orthogonal test, when the pressure was 35 MPa, the oil quality was relatively turbid, and the equipment investment, power consumption and risk were large. The final conditions for supercritical CO2 extraction of millet bran oil are: extraction pressure 30 MPa, extraction temperature 45 ℃, extraction time 2 h, CO2 flow rate 50 kg/h. Under the optimum conditions, the yield of millet bran crude oil can reach 19.69%.

 

Supercritical CO2 fluid extraction experiment

Influence of distillation pressure on distillation

It can be seen from table 3 that with the increase of distillation pressure, the proportion of essential oil fraction obtained from tray I gradually decreases, from 88.5% at 10MPa to 65.9% at 20MPa. This is because the increase of distillation pressure slows down the separation of rice bran oil and supercritical carbon dioxide, and a large number of oil and impurities cannot be completely separated into the separation kettle I, so the distillation column Under this condition, the yield of essential oil is 88.5%.

 

Effect of distillation temperature on distillation

With the increase of distillation temperature, the fraction of essential oil obtained from tray I gradually decreased from 88.5% to 84.2%, and the temperature gradient of distillation column increased, which made part of the oil denatured. This part of oil is easier to flow out through the distillation column with impurities in the separation kettle I, so the distillation temperature should be selected as distillation I: 40 ℃, distillation II: 45 ℃, distillation III: 50 ℃, and distillation IV: 55 ℃.

Comprehensive consideration, the final conditions for supercritical CO2 distillation of millet bran oil are: extraction pressure 30MPa, extraction temperature 45 ℃, extraction time 2h, CO2 flow 50kg / h, column pressure 10MPa, rectification temperature I: 40 ℃, rectification II: 45 ℃, rectification III: 50 ℃, rectification IV: 55 ℃.

 

Quality evaluation of rice bran oil by supercritical CO2 extraction distillation:

Identification of VE and fatty acid composition

The content of VE in Millet bran oil was 12.2mg/g by supercritical carbon dioxide extraction distillation. This shows that the rice bran oil extracted by supercritical carbon dioxide technology is rich in VE.

 

Comparison of rice bran oil with other vegetable oils by supercritical CO2 extraction distillation:

Supercritical fluid extraction of millet bran oil contains higher unsaturated fatty acids, especially up to 67.8% linoleic acid, which is much higher than peanut oil, soybean oil and other daily edible oils. Linoleic acid is an essential nutrient for human body, which can not be synthesized by human body, and can only be taken from food. Therefore, millet bran oil obtained by the research institute has high nutritional value and economic value.

The rice bran oil extracted by supercritical extraction contains higher unsaturated fatty acids, especially 67.8% linoleic acid, which is much higher than peanut oil, soybean oil and other daily edible oils, and the physical and chemical indexes are better than those of rice bran oil on the market.

 

Advantages of supercritical CO2 extraction:

Supercritical CO2 extraction distillation has the characteristics of high oil yield, simple process, no solvent residue and so on. At the same time, millet bran oil with good quality can be obtained. Therefore, it is feasible to extract millet bran oil by supercritical CO2 extraction distillation.

Free supercritical extraction test

China Jiangsu Nantong Huaan Supercritical CO2 Extraction System Co., Ltd has more than 40 years experience of supercritical fluid technology design andequipment manufacturing and it is the high tech company which is committed to the supercritical fluid technology development and supercritical CO2 fluid extraction equipment manufacturing. China a national torch project undertaking unit. Strict implementation of GMP standards, and has passed European CE standard certification, ISO 9001:2000 International Quality Management System Certification, ISO 14001 Environmental Certification and OHSAS 18001 Occupational Health and Safety Certification.

And we specifically supply for our customers custom laboratory, pilot and industrial scale super critical fluid intelligent extraction, dry, reaction, ultrafine grains and other equipment. Also we provide for the customers processing small experiment and cooperation to jointly develop services. Our company not only provides the super critical CO2 extraction distillation, concentration, purification, process technology and equipment of effective components from natural products but also provide the processing technology and equipment of the removal of residual solvent and pesticide residues in products.

Supercritical CO2 extraction of plant essential oils
Supercritical CO2 extraction of plant essential oils

You can send small samples to us and provide extraction requirements. We will help you with free testing in our lab.

supercritical co2 extraction equipment

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