## Method for supercritical CO2 extraction of linseed oil

Determine the oil content of linseed meal→crush the linseed meal→weigh and incorporate into the kettle→supercritical CO2 extraction→separation→linseed oil.

First, the flax meal is crushed, then a certain amount is weighed into the material cylinder, and the kettle is covered. After reaching the experimental setting parameters, cyclic extraction. Discharge once every half an hour until no product is discharged.

## Analysis

### Effect of pressure

According to the best parameters for supercritical extraction of flaxseed in the past (plus references, sample basis), we carried out supercritical extraction of flax meal under pressures of 20Mpa, 25Mpa and 30Mpa.

That as the pressure increases, the extraction rate also increases.

At 30Mpa and 50°C, the extraction can reach 14.8% for 3 hours, and the yield is 92.5%.

This is because the dissolving power of supercritical CO2 is related to its density.

As the pressure increases, the density of supercritical CO2 increases and the dissolving power also increases, so more linseed oil can be dissolved.

### Effect of temperature

In order to study the effect of temperature on the supercritical extraction of linseed oil in linseed meal, we conducted experiments at 40℃, 45℃ and 50℃ under a pressure of 30MPa.

The data obtained after 3 hours of extraction, that as the temperature increases, the extraction rate of linseed oil also increases.

When the temperature rises from 45°C to 50°C, the extraction rate increases by 3.8%, which is a more obvious increase.

This is also related to the increase in the density of supercritical CO2.

### Effect of extraction time

In order to study the effect of extraction time on the extraction rate, we extracted at 20MPa, 25MPa and 30MPa for 3 hours respectively.

The extraction rate at 50°C is the highest under different pressures.

Therefore, the effect of extraction time on the extraction rate of linseed oil at 50°C will be investigated next.

That no matter what the extraction pressure is, the extraction rate of linseed oil increases with time.

At 20 MPa and 25 MPa, the increase in the first 2 hours is faster than the increase in the last 1 hour; and at 30 MPa, The rate of increase in the first two hours and the next hour is basically the same.

It can be seen that at the beginning of extraction, because the extract contains more solutes and is easily taken out by supercritical CO2 dissolution, the amount of extraction is greater and the rate is faster; in the second half of the time, As the concentration of the solute in the extract decreases, the amount taken out by the supercritical CO2 dissolution is reduced, and the rate is also lower.

## Summary

### Extraction rate

The supercritical CO2 extraction method is used to extract the linseed oil in the linseed meal.

At 30MPa, 50℃, the extraction rate can reach 14.8% for 3 hours, and the yield is 92.5%. The linseed oil in the linseed meal is almost completely extracted On the basis of the original pressing, the extraction rate of linseed oil in linseed was increased by about 9%.

### Analysis

After analysis, the content of α-linolenic acid in the linseed oil obtained by supercritical CO2 extraction of linseed meal is about 52%, which is 7 percentage points higher than the 45% of the traditional pressing method.

### Effect of storage conditions

Under the same storage conditions, a Months later, the content of α-linolenic acid in the linseed oil extracted by supercritical CO2 was 50.2%, a small decrease, while the traditional squeezing method was only about 40%, a large decrease, which was a great loss to the manufacturer .

The advantages of supercritical CO2 extraction technology are fully reflected here, and it has great market application prospects in linseed oil extraction.

### Process parameters

Pulverization degree:60 mesh

Extraction pressure: 30 MPa

Extraction temperature: 50°C

Separation pressure I: 14 MPa

Separation I temperature: 45°C

Separation pressure II: 8 MPa

Separation II temperature: 40°C

Extraction time: 180 min