JPH04290502A - Production of oil - Google Patents

Abstract

PURPOSE:To offer such an oil having unsatd. double bond which causes no coloring or molodor. CONSTITUTION:An oil having unsatd. double bond, e.g. soybean oil, is brought into contact with a deoxidizing membrane, e.g. a hollow fiber membrane of poly(4-methylpentene), to remove dissolved oxygen in the oil to <=2ppm through the deoxidizing membrane.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing oil having unsaturated double bonds, and more specifically, it provides a method for producing oil that prevents coloring and generation of bad odors during storage.

0002

[Prior Art] Oils with unsaturated double bonds, such as drying oils and semi-drying oils, are oxidized by oxygen in the air and oxygen dissolved in the oil, or become rancid, causing them to become discolored and smell bad over time. occurs.

[0003] Various measures have been attempted in the past in order to prevent the coloring of oil and the generation of bad odor over time. For example, a method has been used to remove oxygen dissolved in the oil by blowing an inert gas such as nitrogen gas into refined, decolorized, and deodorized oil for a long period of time, but such a method is expensive. and,
The effect of removing dissolved oxygen is also not sufficient. Another method for removing dissolved oxygen from oil is to use a reducing oxygen scavenger (for example, hydrazine), but this is not preferred for edible oils etc. due to toxicity. Furthermore, there is a method of deoxygenating the dissolved oxygen in oil by heating, but in such a method, the oil deteriorates due to heat.
It is colored and is not desirable.

0004

[Problems to be Solved by the Invention] As mentioned above, various methods have been proposed for coloring oil by removing dissolved oxygen and preventing the generation of bad odors. At present, there is no method that is satisfactory in terms of prevention effect, odor prevention effect, etc., and the present invention provides a method for producing oil that is economical, safe, and has excellent coloring and odor prevention effects. be.

[0005]

[Means for Solving the Problems] The present invention provides a method for producing oil by bringing oil having unsaturated double bonds, such as refined, bleached, and deodorized drying oil and semi-drying oil, into contact with a deoxidizing membrane to deoxidize the oil. The present invention relates to a method for producing oil by deoxidizing dissolved oxygen in oil to 2 ppm or less, preferably 0.5 ppm or less via an oxygen membrane.

[0006]

[Constitution] The oil having unsaturated double bonds in the present invention may be any oil having one or more unsaturated double bonds in the oil molecule, that is, in the fatty acid triglyceride, including its production area, purification method, decolorization and deodorization. The present invention is not limited by the method or the like. Such oils include, for example, tung oil, Chinese tung oil, linseed oil, dehydrated castor oil, soybean oil, tall oil, safflower oil, rice bran oil, cottonseed oil, sunflower oil, corn oil, rapeseed oil, sesame oil, etc. alone and/or Alternatively, a mixture of two or more types of oil may be used. Such oils are usually about 13
It contains about 0 ppm of dissolved oxygen.

[0007] In order to remove dissolved oxygen from oil using the membrane type oxygen deoxidizing device of the present invention, it is necessary to lower the dissolved oxygen concentration to 2 ppm or less, and when it exceeds 2 ppm, a sufficient coloring prevention effect and odor prevention effect are obtained. I can't do it. Furthermore, in the case of oils having unsaturated double bonds according to the present invention, such as tung oil having two or more unsaturated double bonds, such as tung oil having conjugated double bonds, the effect of preventing coloration and preventing generation of bad odor can be sufficiently achieved. It is preferable for the dissolved oxygen concentration of the oil to be 0.5 ppm or less.

[0008] The membrane type deoxidation device in the present invention includes:
The oil is brought into contact with a deoxidizing membrane, and a vacuum is applied through this deoxidizing membrane.
Dissolved oxygen can be efficiently removed from the oil to the vacuum and reduced pressure side by the partial pressure difference across the deoxidizing membrane created by reducing the pressure, and there is no contamination by chemicals.
It is possible to obtain oil that is safe as edible oil.

An example of such a membrane type oxygen removing device is shown in FIG. This deoxidizing device generally consists of a membrane module 1 and a vacuum pump 2, and the membrane module 1 is formed by making an oxygen deoxidizing membrane 3 into an element.

[0010] The deoxidizing membrane 3 is not particularly limited as long as it deoxidizes by allowing oxygen to permeate through contact with oil, and may be a composite membrane, a heterogeneous membrane, a hydrophobic porous membrane,
Any material such as a homogeneous membrane can be used.

The material of this oxygen removing membrane 3 is polyethylene, polypropylene, poly(4-methylpentene-1
), polyolefins such as polysulfone, polydimethylsiloxane, polyimide, cellulose acetate, polyester, polyamide, aromatic polyamide, polyether sulfone, poly(2,6-dimethylphenylene oxide),
Fluororesins such as polyvinylidene fluoride and polytetrafluoroethylene may be used singly or in combination, and the present invention is not limited by the material.

Further, if necessary, the oxygen removal effect can be further enhanced by making these membrane materials hydrophilic by ozone treatment, plasma treatment, surfactant treatment, introduction of hydrophilic groups, etc.

[0013] Regarding the shape of the deoxidizing membrane 3, any shape such as a hollow fiber shape, a tubular shape, or a flat membrane shape can be used. but,
Among these, hollow fiber membranes (heterogeneous membranes) with a special sponge-like structure in which air (oxygen) communication holes are formed in the membrane wall are preferred so that air (oxygen) can selectively permeate through the membrane wall. It is.

An oil supply pipe 4 and a deoxygenated oil discharge pipe 10 to which a flow switch 5 is connected are connected to the membrane module 1, respectively. The oil supply pipe 4 is connected to an oil supply source (not shown) via a pressure reducing valve 8, and is branched immediately before the membrane module 1. A branch pipe 9 branched from the oil supply pipe 4 is provided to supply oil to the membrane module 1 at a constant flow rate, and is connected to the vacuum pump 2 via a constant flow valve 0 and a solenoid valve 6. It is connected to the. This vacuum pump 2 is also connected to the membrane module 1 via a solenoid valve 6, forming a vacuum line 7. This vacuum line 7 allows the oil supplied into the module 1 to be deoxidized under vacuum.

[0015] Specifically, such an oxygen scavenger is manufactured by Dainippon Ink & Chemicals Co., Ltd., which is made of poly(4-methylpentene-1) and is described in JP-A No. 63-258605. Examples include the DOR series, a deoxidizing device manufactured by Miura Kogyo Co., Ltd., which uses SEPAREL manufactured by ).

[0016] In order to deoxygenate oil from oil in such a deoxidizer, oil is first introduced into the deoxidizer. Then, the flow switch 5 is activated and the vacuum pump 2 is activated. Then, the two solenoid valves 6 are each opened. Then, the deoxidizing membrane 3 in the membrane module 1 is brought into contact with the oil, and the oil is deoxidized in vacuum through the deoxidizing membrane 3.

For example, when a hollow fiber membrane is used as the deoxidizing membrane 3, the inside of the membrane module 1 on the outside of the hollow fiber becomes a vacuum, and the oil flowing inside the hollow fiber becomes oily depending on the degree of vacuum. Dissolved oxygen therein is deoxidized using a diaphragm vacuum to form deoxygenated oil, which is then discharged to the deoxygenated oil discharge pipe 10. Note that even when the oxygen absorbing membrane 3 has a different shape, the oxygen absorbing membrane 3 divides the vacuum area and the oil area into a vacuum area and an oil area in exactly the same manner as described above, and the inside of the module 1, that is, the outside of the oxygen absorbing membrane 3 is divided into a vacuum area and an oil area. By evacuating the part, the oil flowing inside the deoxidizing membrane 3 can be deoxidized by the diaphragm vacuum to become deoxidized oil.

[0018] The deoxygenated oil obtained by this deoxidizer is normally used under conditions such that the residual dissolved oxygen concentration is 2 ppm or less, but if necessary, it may be used at an even lower concentration, for example, 0.5 ppm or less. It can be done.

Note that the dissolved oxygen concentration in the deoxygenated oil depends on the degree of vacuum obtained by the vacuum pump 2 and the flow rate of the oil, and depending on the operating conditions of the vacuum pump 2, it is possible to obtain the deoxygenated oil with a desired dissolved oxygen concentration. Obtainable.

As described above, in the present invention, the membrane type deoxidizer is used to reduce dissolved oxygen in oil to 2 ppm or less, preferably 0.
By deoxidizing to 5 ppm or less and filling and sealing containers such as cans and plastics, it is possible to produce oil that is free from coloration and odor. Also, when filling and sealing containers with deoxidized oil, do so under a nitrogen gas atmosphere to prevent atmospheric oxygen from entering the container.
Alternatively, it is preferable to replace the air above the container with nitrogen gas after filling the container with oil.

[0021] Furthermore, the container in which the deoxygenated oil is filled and sealed must be a container that is not permeable to gases, especially oxygen.

[0022]

[Examples] The present invention will be explained in detail below with reference to Examples. In addition, the number of parts in the examples represents parts by weight.

[Example 1] The color of purified, bleached and deodorized soybean oil was measured using a Gardner color meter, and the color was 2. Next, a hollow fiber membrane module of poly(4-methylpentene-1) described in JP-A-63-258605 was used.
Separate rail MJ-510 (manufactured by Dainippon Chemical Industry Co., Ltd., hollow fiber membrane inner diameter 200 μm, membrane thickness 25 μm, total membrane area of the hollow fibers used in the module 13 m2). - Deoxidizer Z-Savin DOR shown in 1
(manufactured by Miura Kogyo Co., Ltd.) was used to remove oxygen dissolved in the soybean oil. The dissolved oxygen concentration of the obtained deoxygenated oil was 1.8 ppm. Next, put this deoxygenated oil into a can, replace the air at the top of the can with nitrogen gas, seal it, and then
After being left in a constant temperature bath at 60°C for 6 months, the package was opened and the color of the oil was measured, and the color was 2. Moreover, the odor of this oil was no different from the odor before it was left to heat for 6 months.

[Example 2] Oil deoxygenation and heat coloring tests were carried out in the same manner as in Example 1 except that Color-5 refined linseed oil was used instead of refined soybean oil. The dissolved oxygen concentration of the deoxidized oil was 0.4 ppm, and the odor of the color after being heated for 6 months at 60°C was almost the same as the odor before the heating test.

[Example 3] Oil deoxygenation and heating storage tests were carried out in exactly the same manner as in Example 2 except that the dissolved oxygen concentration of the deoxygenated oil was 1.9 ppm. The color after being heated for 6 months was 5-6. Moreover, the odor of the oil after being left to heat for 6 months was almost unchanged from before being left to be heated.

[Example 4] Instead of refined, bleached, and deodorized soybean oil, 40 parts of refined, bleached, and deodorized soybean oil, 20 parts of corn oil, and 20 parts of rapeseed oil were mixed.
Deoxidation and heating storage tests were carried out in exactly the same manner as in Example 1, except that the mixed oil of No. 2 was used. The dissolved oxygen concentration of the deoxygenated oil was 0.3 ppm, the color after heating was 1 to 2, and the odor was completely unchanged from before heating.

[Comparative Example 1] A heating storage test was carried out in the same manner as in Example 1 except that the soybean oil was heated at 60° C. for 6 months without deoxidizing it. The color after heating and standing was 4. In addition, an odor peculiar to polymerized oil was observed.

[Comparative Example 2] A heating storage test was carried out in exactly the same manner as in Example 2 except that the linseed oil was heated at 60°C for 6 months without deoxidizing it. The color after heating and standing was 8. In addition, a fairly strong odor peculiar to polymerized oil was observed.

[0029]

Effects of the Invention The present invention deoxidizes oil having unsaturated double bonds in vacuum through a deoxidizing membrane to reduce the amount of dissolved oxygen to 2 ppm.
Coloring of the oil and generation of bad odor can be prevented by doing the following.

[0030]

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a membrane-type oxygen removing device used in the present invention.

0000

[Explanation of symbols]

0 Constant flow valve 1 Module 2 Vacuum pump 3. Oxygen removal membrane 4 Stock solution supply pipe 5 Flow switch 6 Solenoid valve 7 Vacuum line 8 Pressure reducing valve 9 Branch pipe 10 Deoxygenated oil discharge pipe

Claims (2)

[Claims] 1. A method for producing oil, which comprises bringing an oil having unsaturated double bonds into contact with a deoxidizing membrane and deoxidizing the oil to a dissolved oxygen concentration of 2 ppm or less through the deoxidizing membrane. Claim 2: The dissolved oxygen concentration of the deoxygenated oil is 0.5 pp.
2. The method for producing oil according to claim 1, wherein the amount is less than or equal to m.