JPS60238395A - Purification of vegetable oil - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for refining vegetable oil using a semipermeable membrane or a porous membrane together with the semipermeable membrane.

(Prior Art) Crude crude oil is obtained by pressing or extracting oil from oil seeds, but in the process of refining this crude crude oil, natural contaminants, unnecessary substances, etc. contained in the crude crude oil are removed. For example, it contains phospholipids, sulfur compounds, free fatty acids, hydrocarbons, heavy metals, peptides, sugar starches, aldehyde ketones, sterols, terpene glycosides, and many pigments, which are excluded. must be done.

For example, phospholipids can be removed simply by adding water to crude oil, and other methods commonly used include using chemicals to make them easier to remove. Free fatty acids are removed by treatment with an alkaline chemical such as caustic soda. Pigment substances are destroyed or removed by heat treatment with an adsorbent such as activated clay or activated carbon. Furthermore, in the final step, steam distillation is performed to remove odor components (aldehydes, ketones).

In the process of refining crude oil, some of the above treatment methods are extremely difficult and have several drawbacks. For example, the degumming effect often depends on the quality of the crude oil, and if the crude oil has a high phospholipid content, there are problems such as an increase in the amount of chemicals and a decrease in yield. It is well known that the quality of the final product is poor. Furthermore, in the deacidification step, the soap and glycerin aqueous solution produced by the alkaline reaction and phospholipids tend to emulsify, resulting in a highly contaminated waste solution being discharged. On the other hand, compressed crude oil generally contains a large amount of soft mud, which is separated into solid and liquid using a centrifuge, and the oil is then passed through a filter press to obtain a clear liquid, which is then sent to the degumming process. . The filtration step in such pretreatment is also a part that is difficult to be continuous or automated.

Furthermore, although many patents are known for methods of refining vegetable oil using membranes, no examples have yet been found that have been put to practical use on an industrial scale. The most efficient and common membrane treatment method for refining oil is passing it through a semipermeable membrane in micellar form, as seen in the Unilever patent (Japanese Unexamined Patent Publication No. 50-153010).
On the other hand, the method of passing crude oil through a membrane is also disclosed in the Ajinomoto patent (Japanese Unexamined Patent Publication No. 57-5793), but the amount of permeation does not increase and it is difficult to implement on an industrial scale. What can be said from an industrial perspective when applying micellar or crude oil to a membrane is how much permeation flow rate can be ensured, and how to reduce the number of backwashes as much as possible to speed up the recovery of the membrane. This means that it is desirable for driving.

In the methods currently used with micella and oil, the concentration and amount of suspended solids and phospholipids contained in the undiluted solution and micella are
A method is used in which the membrane is brought into direct contact with pressure without pretreatment, but in this method, phospholipids and other suspended substances also load the membrane, reducing the number of cleaning cycles. It has the disadvantage of being inefficient because it has to be done frequently.

(Problem to be solved by the invention) In the method of refining vegetable oil using a membrane, phospholipids or other suspended substances become a load on the membrane, and washing must be performed frequently. However, there was a problem of poor efficiency.

(Means for Solving the Problem) In order to eliminate the drawbacks of conventional vegetable oil refining methods, the present inventors have proposed that the filtration and degumming steps of crude oil should be carried out using a membrane. As a result of studying methods for refining vegetable oil using membranes, we found that
Vegetable crude oil or micellar) #'C Add water and/or acid to make the phospholipid contained in the vegetable crude oil or micellar into a hydrated gum, and remove the suspended solids and wax content together with the hydrating gum. We have discovered that the above problem can be solved by removing most of the phospholipids in vegetable crude oil or micella by precipitation separation, and feeding the membrane with a product with a reduced phospholipid concentration of ~%. This led to the completion of the present invention.

Vegetable crude oils to which the present invention is applied include soybean oil, rapeseed oil, sunflower oil, corn oil, safflower oil, linseed oil, sesame oil, peanut oil, menzi oil, rice oil, etc. When trying to apply the film K,
Of the phospholipids contained in the stock solution, approximately 50 water-use phospholipids are insolubilized by simply adding water.
Can be separated by sedimentation. On the other hand, non-hydratable phospholipids are converted to water-friendly phospholipids by treatment with acids such as phosphoric acid, citric acid, oxalic acid, acetic anhydride, and sulfuric acid, and then insolubilized (hydrated) by adding water. It can be precipitated and separated in oil, oil or micellar solution.

The method of removing phospholipids from vegetable crude oil does not necessarily require the use of chemicals such as acids; it is possible to remove 50% of phospholipids using only water.
Good results can be obtained even when the stock solution after insolubilizing and removing more than % is fed to a semipermeable membrane. If you want to completely remove it, you can convert non-hydratable phospholipids to hydrated phospholipids with acid after water addition and irrigation. Even so, it can be completely removed (due to the difference in molecular weight fraction) in the subsequent semipermeable membrane filtration treatment. At this time, the load on the membrane is small, and the amount of concentrated soapstock that removes insects is small, so there is less adhesion to the membrane and the backwashing time is extended, making it extremely advantageous compared to conventional methods. be.

In the present invention, the micella may be extracted micella mixed with pressed oil to have a micella concentration of 20 to 80%, but preferably the micella concentration is adjusted to 60%. The temperature of the addition treatment of water and/or acid is 30 to 60C,
The reaction maturation time is within 50 minutes, and practically 5 to 1
0 minutes is preferable. If the sedimentation separation after the water and/or acid addition treatment is carried out at the same temperature as the water and/or acid addition treatment, the separation is rapid and continuous large-scale treatment is possible. However, micellar sedimentation is relatively easy to separate even at low temperatures. The separation method does not require a centrifuge or the like, but can be performed continuously using a stationary tank or a separator. Due to this sedimentation separation, the supernatant liquid contains some phospholipids, phospholipids, suspended substances, etc. that cannot be separated, but in order to reduce the load on membrane filtration in the next step, the sedimentation conditions are adjusted as much as possible. It is desirable to do well.

The above supernatant liquid can be filtered as is through a semipermeable membrane, or it can be filtered through a porous membrane and then filtered through a semipermeable membrane. It is preferable to do so. The semipermeable and porous membranes used are
Commercially available ones with pore diameter of 0.01 to 1μ, 30,000
Any hydrophobic material with a molecular weight cut-off of 0 to 100,000 may be used, but polysulfone-based, polyacrylonitrile-based, vinylidene fluoride-based or polyethylene-based materials are preferable.

The supernatant liquid is filtered by cryogenic filtration, especially with a porous membrane.
Since the precipitated wax content can also be removed, in the present invention, if the supernatant liquid is cooled and filtered, dewaxing can also be performed at the same time.

The method of the present invention explained above is shown in 7' sheet as follows.

11: Micella → Water → Sedimentation → Supernatant → Semipermeable membrane (21 Micella →
Acid → Water → Sedimentation → Supernatant → Semipermeable membrane (3) Micella → Acid → Water → Sedimentation → Supernatant → Porous membrane → Semipermeable membrane (41 Oil → Water → Sedimentation → Supernatant →
Semipermeable membrane (5) Oil→acid→water→sedimentation→supernatant→porous membrane→semipermeable membrane (Example) Example 1 Rapeseed misella containing 1J/1lff 1.7% (micella 60%, solvent normal hexay40 %) Total 45
While keeping CK warm, add 5% water to the rapeseed T. sera, stir vigorously to mix uniformly, and then stir weakly for 20 minutes to form phospholipid flocs by water utilization reaction. The flocs are sedimented to obtain supernatant miscella. The phospholipid content of the obtained supernatant micella was 0.6%.

This supernatant micella is directly used as a feed solution to the semipermeable membrane. The semipermeable membrane used was 5IP-1015 (molecular weight cut off: 6,000) manufactured by Asahi Kasei (Kiyoshi Kasei), and permeation through the membrane was carried out at a temperature of 20C, a pressure of J, and 5 kP, and desolvation of the membrane-permeated miscella yielded degummed oil. The results of examining the obtained degumming effect and permeation efficiency are shown in Table 1.

Example 2 Rapeseed Micella (Micella 60) containing 1.7% phospholipids
%, solvent normal hexane (40%) at 45C, add and mix citric acid aqueous solution (50%) to the oil in an amount of 0.3% to change the contained phospholipids into hydrated type. . When adding the aqueous citric acid solution, stir vigorously to ensure good dispersion. After dispersion, the reaction begins, which also serves as aging, and is stirred weakly for 20 minutes. Furthermore, 5 grams of water was added to this and stirred in the same manner as above.
After forming the phospholipid flocs, the flocs are sedimented to obtain supernatant micelles. The phospholipid content of the obtained supernatant micella was 0.7%.

This supernatant micella is directly fed to the semipermeable membrane. Degummed oil was obtained in the same manner as in Example 1, except that the membrane permeation temperature was 50°C. The results of examining the obtained degumming effect and groove efficiency are shown in Table 1.

Example I5 “Bola rape miscella (60% miscella, solvent n-hexane 40%) containing 1j1.71 of phospholipids was treated with an aqueous citric acid solution and water treatment in the same manner as in Example 2. Lipid content is 0.7%
Met.

This supernatant micella is used as it is as a stock solution to be fed to the porous membrane. The porous membrane used was 'l'p-115 (average pore diameter 0.9μ) manufactured by Asahi Kasei, and after filtration was performed at a temperature of 50C and a pressure of 1.50, it was further filtered with a semi-permeable membrane in the same manner as in Example 2. Processing to obtain degummed oil. The results of examining the obtained degumming effect and permeation efficiency are shown in Table 1. Table 1 also shows cases where the porous membrane was filtered at 18C and the other conditions were the same as above.

Example 4 Rape rape containing 1.7% phospholipid
% solvent n-hexane 40%) and phospholipid 1.5
% was hydrated in the same manner as in Example 1 to obtain a supernatant. The phospholipid content of the obtained supernatant rapeseed miscella was 0.5%, and the phospholipid content of the soybean oil supernatant was 0.4%. Each of these is filtered through a semipermeable membrane in the same manner as in Example 1 to obtain degummed oil. The results of examining the obtained degumming effect and permeation efficiency are shown in Table 1.

Example 5 Soybean oil containing 1.5% phospholipid was treated with citric acid and hydrated in the same manner as in Example 3 to obtain a supernatant. The phospholipid content of the obtained supernatant was 0.4%. This is filtered through a single porous membrane in the same manner as in Example 3, and then filtered through a semipermeable membrane to obtain a degummed oil. The results of examining the obtained degumming effect and permeation efficiency are shown in Table 1.

Comparative Example 1 The same rapeseed rape as in Example 1 was treated in exactly the same manner as in Example 1, except that water utilization treatment was not performed. The results of examining the degumming effect and permeation efficiency are shown in Table 1.

Comparative Example 2 The same soybean oil as in Example 4 was treated in exactly the same manner as in Example 4, except that the hydration treatment was not performed. The results of examining the degumming effect and permeation efficiency are shown in Table 1.

Table 1 (Effects of the Invention) According to the present invention, the phospholipid concentration in the oil after filtration is 0.03.
% or less, the quality of crude oil i is greatly improved compared to conventional methods, and the amount of chemicals used can be greatly reduced.

Agent Takeshi Kiyomizu

Claims (1)

[Claims] 111 Water and/or acid is added to vegetable crude oil or micellar, and the phospholipids mainly contained are compressed into a water-use gum, so that the mixed floating substances and wax content are sedimented and separated along with the water-use gum. A method for refining vegetable oil, which is characterized in that the supernatant liquid is then filtered through a semipermeable membrane. (After adding water and/or acid to 21 vegetable crude oil or micella, compressing the phospholipids mainly contained in the hydrated gum, and separating the mixed floating substances by sedimentation along with the hydrated gum) , a method for purification of cypress powder, which is characterized in that the supernatant liquid is passed through a porous membrane and further filtered through a semipermeable membrane.