NL8003649A - METHOD FOR REFINING OILS AND FATS. - Google Patents

Description

* »I (..: * t. ·" Process for the refining of oils and fats ",

The invention relates to a method for refining oils and fats.

Various processes for refining oils and fats have been developed. Alkaline refining is used extensively and is an important method of refining fats and oils, as it has many advantages over the other methods. A major problem that has only recently become significant from the point of view of environmental pollution and raw material conservation is that. alkaline refining produces a large amount of wastewater.

In ordinary alkaline refining, crude or degummed oils and fats of animal and vegetable origin are brought into contact with an alkaline solution in water. Free fatty acid in the oils and fats then reacts with the alkaline solution and the oils and fats are deacidified to form soap lime, which mainly consists of fatty acid soap, which is centrifuged as shown in the attached scheme A.

The deacidified oil, after separation of the soap, is then mixed and stirred with a large amount of hot water to obtain sufficient contact of the oil with the hot water.

Soap, which remains in the oil in an amount of 100-1000 mg / kg depending on the type and the centrifuge, is transferred to the liquid phase and centrifuged again. Only one such washout is not enough and therefore one must wash more than twice in order to exhaustively remove the soap from the oil. A very large amount of wastewater is therefore produced during this washing out.

Since this wastewater contains a significant amount of impurities, including soap and entrained oil, this wastewater should not be discharged without treating it by the pressure flotation method or the activated swallowing process. Huge investments are therefore required for the waste water treatment device. The centrifuge or mixing and stirring device to be used in the scrubbing process is very expensive and the number of these devices depends on the number of times it is washed. Washing twice requires two of these devices. Even the washing process only in the oil refineries requires a large investment and 15 places a heavy economic burden on the manufacturers. It is also undesirable from the viewpoint of raw material saving to use such a large amount of water and this must therefore first of all be reduced. Thus, the usual alkaline refining process is becoming increasingly disadvantageous.

The object of the invention is now to provide an economical method for refining oils and fats.

The present process has now eliminated the washing process, thereby avoiding production of waste water and the associated environmental pollution. The method of the invention has also eliminated the investment for the equipment needed to wash the neutralized oils and fats with water and treat the wastewater.

The invention relates to a method for refining animal and vegetable oils and fats and in particular to a method for refining crude oils and fats of animal and vegetable origin or oils and fats which have been subjected to a conventional pretreatment . The invention is characterized in that these oils and fats are deacidified with an aqueous solution of alkaline compounds, the soap lime thus formed is centrifuged off the deacidified oils and fats, the deacidified oils and fats after removal of the lime soap, without washing it out, mixes with an acidic aqueous solution, optionally dries the resulting mixture, treats the mixture with adsorbent and steam-distills the oils and fats.

Methods for refining oil have been investigated, whereby after deacidification, washing is no longer carried out in accordance with the usual alkaline refining method, so that the production of waste water can be avoided, so that the present invention is obtained. When refining animal and vegetable oils and fats according to the invention, washing of the usual alkali refining is omitted and washing is replaced by a simple acid treatment. The refining itself has therefore been considerably simplified. Since in the refining process according to the invention separation by centrifugation of oil and water takes place as in the usual washing out, the expensive centrifuge is unnecessary and no waste water is produced.

The refining of fats and oils according to the invention comprises the following steps: 1. treatment of oils and fats with alkaline solution (deacidification), 2. separation of insoluble matter, 3. treatment of oils and fats with an acid solution in water, 1 ». treatment of oils and fats with adsorbent (decolorization), 5. steam distillation of oils and fats (deodorization).

The details of these steps are discussed below.

1. Treatment with alkali.

This step is an ordinary deacidification step, which speaks for itself. The animal and vegetable oils and fats 8003649k are subjected to pretreatment, if required, for example, physical removal of contaminants from the oil by filtration or sedimentation or degumming with water, acid, alkali or other chemicals. Gum treatment with acids such as phosphoric acid can also be carried out in the usual manner. However, the pretreatment is optional.

The alkali treatment is effected by contacting the oils and fats with an alkaline aqueous solution to neutralize free fatty acid, saponify the gummy substance, hydrate and coagulate and decolorize the dye in the oils and fats. Usually, alkaline compounds such as sodium hydroxide and soda are added to the oil. Soaps and gum coagulated are suspended in the mixture as an insoluble matter.

15 2. Separation of insoluble matter.

This step is common in ordinary alkaline refining. The insoluble material formed in the oil in the previous alkali treatment is centrifuged from the oil as soap lime. This soap lime mainly consists of soap and contains entrained neutral oil and impurities as gum-like substance.

3. Treatment with acidic aqueous solution.

In the ordinary alkaline refining, the oil is washed after a step 2 (hereinafter referred to as deacidified, separated oil) with a large amount of water. The feature of the invention is now that step 3 is carried out directly without washing out the deacidified separated oil with water.

The deacidified separated oil usually contains, as described above, an amount of soap of 100 to 1000 mg / kg and a small amount of impurities such as slime. The deacidified separated oil is treated in this step 3 with an acidic aqueous solution to remove the oil hydrolyzing soap present into free fatty acid and salts. Impurities such as mucus present in the oil in a small amount are simultaneously coagulated as insoluble in the oil. The free fatty acid thus formed dissolves in the oil and the impurities and salts remain in the oil as an insoluble matter.

The acids used in this step are organic or inorganic acids such as hydrochloric, sulfuric, phosphoric, oxalic, acetic, acetic anhydride, citric and tartaric acids or a combination of two or more of these acids. Phosphoric acid is most suitable from an economic point of view and in view of the influence on the material of the device. The acid is added in a suitable concentration to the deacidified, separated oil and the mixture is mixed or stirred for a few seconds to a few hours at a temperature of room temperature up to 100 C. If using phosphoric acid, it is dissolved in 75-85 % aqueous solution and if citric acid is used, use 73-80% aqueous solution. Lower acid concentrations can also be used in this step, but the acid concentration is preferably as high as possible in connection with the next step 1 *. The large contact time range is related to the efficiency differences between the mixers that may be used. In short, it is necessary to achieve a uniform and intimate contact between acids and soaps or mucus in order for the mutual reaction to proceed quickly and sufficiently. In this step, one can also use the equipment used in the alkaline refining to contact the oil with alkali or water.

The contact between acids and soaps or slimes can be accelerated by using a homogenizer.

The amount of acidic aqueous solution to be added is mainly calculated on the amount of acid required to decompose the soap contained in the deacidified separated oil and is determined taking into account the amount of impurities such as slime in the oil. If the soap content of the oil is 1000 or 100 mg / kg, 380 to 38 mg / kg has 85% phosphoric acid and if 100% acetic acid is used, 197 mg / kg or 19.7 mg / kg, to decompose the need soap.

The oil is dried after this treatment, if necessary, in a suitable dryer to remove excess water from the oil for the next step treatment.

800 36 49 5a 4. Treatment with adsorbent (discoloration),

This step is an ordinary discoloration. The oil treated with acid in step 3 or the oil dried after the treatment in step 3 is treated with an adsorbent, such as activated clay or activated carbon.

The impurities remaining in the oil such as 800 36 49 6 slimes, salts formed by the reaction of acid with soaps and the colorant in the oil are almost completely adsorbed on the adsorbent and removed from the oil. The method of treatment, the conditions and the device can be the same as in the known decolorization.

5. Steam distillation (deodorization).

This trap is an ordinary deodorization. The fatty acid released by the acid treatment at step 3 is completely distilled off from the oil together with fragrant substance. The dye in the oil is simultaneously decomposed by the heat and the oil changes to light-colored. Since the impurities, such as slime, have already been completely removed from the oil, the oil does not color due to the presence of impurities. This steam distillation can be carried out in the usual manner.

The above is an embodiment of the invention. The effect and advantage of the invention is that the washings used in ordinary alkaline refining are omitted, so that an expensive device such as a centrifuge is not required in the present process. The impurities and soaps which are removed from the oil by ordinary washing are treated with acid in the deacidified separated oil in the present process and are completely removed from the oil in the subsequent decolorization and deodorization.

In order to treat the oil with an acidic aqueous solution according to the invention, only a mixing device is required in an oil refiner. Two washes at the wash stage require two sets of devices such as a centrifuge and a mixer in a conventional refiner.

The cost reduction with respect to the equipment is estimated at more than 100 million yen by the standards of 197¾, since wash stage equipment such as centrifuge and mixer is no longer needed. This amount was calculated for oil refinery with an average capacity of 8003649 7200 tons per day. In addition, the costs of operating and maintaining the installation and the costs of putting these installations under roof as costs for land and buildings are unnecessary. The method of the invention therefore has an invaluable economic value over the known methods.

The present method does not involve the formation of waste water and is therefore clearly a method in which the environment is protected against pollution. The method of the invention saves on the water consumption, the heat energy 10 for heating the washing water and the energy for driving the washing machine. The present process is easy to carry out in oil refining. The quality of the refined oils and fats obtained by the present process is substantially equal to that of oil produced by the usual alkaline refining method and the oil yield is even better than in the known method.

In conventional alkaline refining, if the washing is omitted and the amount of adsorbent is increased to remove soaps, impurities and dyes left in the oil without treating the deacidified oil with acid, as in the present process, advantage of not doing the washing out. However, compared to the present process, a very large amount of adsorbent is then required. Therefore, a large amount of oil with the adsorbent is lost and the drawbacks caused by the increase in expenses associated with adsorption and by the decrease in oil yield do the benefits of omitting the washout. iiet. Such a method is therefore of no economic significance and is therefore of course far less so than the present method.

The present process can be used to refine all kinds of vegetable and animal oils and fats such as soy oil, rapeseed oil, rice oil, corn oil, cotton seed oil, sunflower oil, safflower oil, sesame oil, peanut oil, palm oil, coconut oil, linseed oil, lard, beef tallow , sheep's talk, fish oil and 80036 49 Λ fc '8 oils and fats, which are present from sea animals.

The following examples illustrate the invention.

Example I

Soybean oil was treated with alkali in the usual manner. The deacidified separated oil was obtained by centrifuging the soap-lime from the oil. The oil was divided into four samples and used for the following experiments. The properties of the deacidified, separated oil are shown in Table A.

10

Experiment 1 (Method according to the invention (1)).

Ko mg / kg 85% phosphoric acid was added to the deacidified separated oil and the acid treatment was carried out by stirring the mixture at 80 ° C for 5 min. Then 0.3 parts by weight of activated clay earth was added to the acid-treated oil and the oil was decolorized under reduced pressure at 105 ° C for 15 min. And the activated clay earth was separated from the mixture. The decolorized oil thus obtained was subjected to steam distillation under vacuum at 250 [deg.] C. for deodorization. The refined oil was thus obtained.

20

Experiment 2 (Method according to the invention (2)).

This test was carried out under the same conditions as in Example 1, except that the amount of phosphoric acid was changed to 80 mg / kg.

25

Experiment 3 (Comparative experiment (1); the known method).

The deacidified separated oil was washed with 20% hot water, based on the oil and centrifuged. After washing, decolorization and deodorization were performed twice under the conditions described in run 30L.

Trial 4 (Comparative Trial (2)),

The deacidified separated oil was directly decolorized and deodorized under the conditions described in Test 1 without acid treatment or washing.

800 3 6 49 9

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800 3 6 49 10

The properties of the oil at each stage in Runs 1-4 are shown in Table A.

As can be seen from the results of Table A, refining according to the invention (in tests 1 and 2) gives refined oil having substantially the same properties and quality as the oil obtained in known manner (according to test 3) by deacidified separated oil only to be treated with phosphoric acid without washing out with water. Since the decolorizing and deodorizing conditions in the process of the invention need not differ from those in the known process, they do not affect the yield of refined oil. The method of the invention is considerably better than the known method as regards the yield of refined oil, since the known method causes losses of neutral oil which is entrained in the washing water.

If the deacidified oil is directly decolorized and deodorized without treatment with acid and washing with water (in test 1+), soaps and phospholipids are not sufficiently removed.

The quality of the refined oil is therefore poor.

It was found in the test that an amount of activated clay of 0.8% t was required, which is more than twice as much as in the present process, in order to increase the quality of the refined oil of test b to the level of that of the oil of Runs 1 and 2. The cost increase for refining the oil by this method compared to the method of the invention is 1000 yen per ton of oil.

Example II

Rapeseed oil was treated with alkaline solution in the usual manner and the soap lime was centrifuged off. 1 * 31 mg / kg 30% aqueous citric acid solution was added to the deacidified separated oil, which had an acid value of 0.06, a soap content of 205 mg / kg and a phospholipid content of 283 mg / kg. The mixture was stirred at -50 ° C for 30 min. Then 0.6 wt.% Activated clay was added to the oil and the oil was decolorized at 105 ° C for 15 min.

800 36 49 11

The activated clay was separated from the oil. The oil was deodorized for 1 * 5 min by steam distillation under reduced pressure at 250 ° C.

Refined oil was thus obtained. This had an acid number of

Y R

0.05, a color of 6 x 0.5 and a phospholipid content of 5 mg / kg.

The quality of the refined oil was almost the same as that of known refined oil.

Example III

Maize oil is deacidified in the usual manner with alkali and the soap lime is centrifuged off to obtain an acidified separated oil. 6ol * mg / kg 20% aqueous hydrochloric acid solution was added to the deacidified separated oil, which had an acid value of 0.08, a soap content of 990 mg / kg and a phospholipid content of 368 mg / kg. The mixture was stirred at 80 ° C for 5 min. After that, 0.6% by weight of activated clay was added to the oil and the oil was decolorized at 105 ° C for 15 minutes. After the activated clay had separated from the oil, the oil was deodorized by steam distillation under reduced pressure at 60 ° C for 60 min. Refined oil was thus obtained. It had an acid number of 0.07, a color of 6 x 0.6 and a phospholipid content of 13 mg / kg. The quality of the refined oil was almost the same as that of known refined oil.

Example IV

Deacidified bovine talc is removed by the usual alkali treatment and the soap lime is separated from the lime to obtain an deacidified separated talc with an acid number of 0.06, a soap content of 205 mg / kg and a phospholipid content of 5. kg. 1 * 5 mg / kg of 93% acetic acid was added to the talc and the mixture was stirred at high speed for 30 sec. at 90 ° C with a Dispermill (supplied by Hosokava iron works). 2% by weight of activated clay was added to the oil and the oil was decolorized under reduced pressure at 100 ° C for 30 minutes. The oil was deodorized by steam distillation under vacuum at 250 ° C for 90 min. A refined oil with an acid number of 0.02, a color of 1 x 0.1 and a trace of phospholipid was thus obtained.

800 36 49

V

12

The refining method of the invention eliminates the need for rinsing after deacidification and separation of the soap lime from the deacidified oil and the usual alkali refining as shown in the examples, and the refined oil can be obtained in good yield in the same quality as in the known art. way refined oil.

Since the economic costs for the acid treatment manufacturers of the invention are very low compared to the advantage of eliminating the scrubbing, the present process is much better than the prior art. The present process does not produce wastewater and saves the consumption of valuable water and therefore makes a major contribution to oil refining.

80036 49

Claims (2)

Method for refining an animal or vegetable oil or fat, characterized in that a. The oil or fat is mixed with an alkaline solution in water, b. separates the insoluble matter from the resulting mixture, c. the deacidified, separated oil or fat product from step b. mixed directly with an acidic solution in 10 water, d. treat the resulting mixture with an adsorbent to remove dye, impurities and during step c. adsorbing formed salts, e. separating the adsorbent from the oil or fat 15 and f. the oil or fat after step e. by deodorizing steam distillation. 2. Process according to claim 1, characterized in that after step c. and for step d, the resulting mixture dries to remove excess water. 80036 49