DE2229304C2 - Process for the refining of crude palm oil type oils - Google Patents

Description

The invention relates to a process for the refining of crude oils of the palm oil type using phosphoric acid and subsequent addition of active clay at an elevated temperature and subsequent steam refining. As used herein, "raw palm-type oils" includes both Palm oil itself as well as natural oils containing palm kernel oil, coconut oil and the like.

The known method of refining Paimo type crude oils comprises steam distillation under high temperature and high vacuum. In this steam distillation method, two refining processes, neutralization and deodorization, are carried out at the same time. This process is carried out on a large scale Scope applied and is favorable, since refining losses of neutral oil, for example entrained goods in the soap mass and saponification by alkali, which occurs with alkali refining methods, are avoided are kana However, with the steam dilution method it is necessary to place a large amount of adsorbent in the to employ foregoing treatment methods, and for this reason, alkali refining methods have conventionally been used in an economical manner

In the above-mentioned methods, a decolorization process is necessary. In the steam refining method, the crude oil is decolorized before steam distillation. In the case of palm oils, a decolorizing The exercise process is extremely important because it contains a considerable amount of raw material have coloring substances.

It is particularly difficult to discolor palm oil because it contains large amounts of carotenoids.

In a known process π for decolorizing palm oil, the coloring substances are absorbed by adsorption, For example, activated clay or activated carbon, removed It is necessary, however, to decolorize the oils a large amount of adsorbent in proportion to the amount of coloring matter contained therein use, and refining losses are caused by the neutral oil entrained in the adsorbent Despite the many advantages that accompany this process, it counteracts the economic application of steam refining for palm oils.

In steam refining methods, heat-sensitive coloring materials such as carotenoids can be decomposed and decolored by heat in the course of refining, but this has no effect heat-insensitive substances. For these reasons, it is impossible to completely decolorize palm oils by steam refining. Therefore, refining palm oils is not just about heat treatment, but also about it treatment with adsorbents is necessary. In addition, it is used to completely discolor these oils required to use a large amount of adsorbent in order to obtain satisfactory discoloration.

In US-PS 24 58 554 is a method for cleaning is described of oils, according to which the crude oil was mixed with a strong mineral acid introduced into the mixture, bleaching earths, and then acid-activated earth, oil mixture heats to the temperature range of 90 to 120 ⁰ C. and then the fuller's earth is filtered off. Sulfuric acid is used as the strong mineral acid. In this known process, the content of ash-forming substances contained in the oils, such as phosphatides, is to be reduced. The palm oil type oil, however, is essentially practically free of phosphatides.

GB-PS 12 69 904 describes a process for refining oil in which the oil is heated with phosphoric acid and ^{treated with a bleaching adsorbent at a temperature in the range from 121 to 260 °} C. in the absence of air. If, however, an oil of the palm oil type is to be treated according to this known procedure, the coloring material contained in the oil, consisting of the carotenoids, is converted into a substance which cannot be decolorized in the subsequent steam refining process. This is also shown below on the basis of comparative tests.

The DE-OS 20 37 934 describes a process for the refining of fatty substances, wherein heating the fatty substance in the presence of bleaching adsorbent and phosphoric acid at about 121-260 ⁰ C. This procedure is also not suitable for obtaining satisfactory decolorization of the refined oil.

The US-PS 32 84 213 describes a method for inhibiting breakage and preventing foaming in heated baking oils. Here, concentrated phosphoric acid is added to the purified oil, and the oil is heated slowly to about 100 ⁰ C. A bleaching clay is then added and the oil is further heated to about 120 ° C., whereupon it is cooled and the oil is filtered to remove the bleaching clay and phosphoric acid. The phosphoric acid acts directly on the triglycerides themselves to prevent them from breaking and to avoid polymer formation. The properties of such oils are substantially different from the crude palm oil type oils.

The object of the invention is to provide a method for refining crude oils of the palm oil type

ä 'using phosphoric acid and subsequent addition of active clay, wherein the oil in the' color-forming carotenoids contained weriien can satisfactorily decolorized.

This object is achieved according to the invention by creating a method for refining

ν of crude oils of the palm oil type with the application of phosphoric acid and subsequent addition of active

£ clay at elevated temperature and subsequent steam refining, which is characterized in that; % Adding 0.01 to 2.0% of phosphoric acid at a fiüssigen oil from palm oil type, the oil and the acid to ^r>: mixed together thoroughly stirring the resulting mixture with activated clay mixes, while .. "■ 'the temperature the mixture is raised to a temperature in the vicinity of about 100 ⁰ C, the mixture is held at this temperature for 5 to 30 minutes, this treatment being carried out so that the oil treated in this way does not have any significant discoloration and the characteristic peaks of the absorption spectrum for. / 9-carotene remains essentially unchanged in the crude oil, whereupon the clay is removed from the oil and the oil is simultaneously decolorized, deodorized and deacidified by steam refining.

It has been found that when the method according to the invention is carried out, palm oils are effective ; can be decolorized using small amounts of activated clay.

The color of the oil obtained after the clay is removed is practically the same as that of the crude oil material, although the treatment according to the invention has been carried out, however, if then that • The oil obtained is subjected to steam refining, with superheated steam in the oil under high

] i vacuum is blown at above 200 ° C, a very light colored and odorless oil is obtained.
'% Although the pretreatment according to the invention is similar to a decolorizing process before a conventional one

ϊ £ Steam refining is carried out, there are essential differences. In the usual procedure t will change the color of the oil by treating it with an adsorbent such as bleaching clay

g eliminates the pretreatment according to the invention, in which the color of the oil is not due to the treatment with ΐ activated clay is eliminated and the color of the crude oil is the same of the invention no discoloration, as is readily apparent from the reproduced in the drawing ■■ ": ■; Adsorption spectrum can be seen in the visible range.

The palm oil pretreated with phosphoric acid and activated clay by the process according to the invention gives curve 3, and the untreated crude palm oil gives curve Z. These curves have an absorption peak due to the presence of ^ -carotene which is at the same wavelength as that of the absorption of / "-Carotene, as can be seen from curve 1, indicates that no discoloration took place in the pretreated palm oil. On the other hand, palm oil A, which yields curve 4 and which has only been treated with activated clay according to conventional methods, has no absorption peak of the / 7-carotene, and the intensity of the extent of absorption is much lower, which shows that discoloration of the oil took place.

In the process according to the invention, the discoloration takes place practically exclusively during the steam refining. The oil is thoroughly decolorized by steam refining. Diss is one of the most characteristic Features of the invention and represents a novel idea for refining oils, in the case of neutralization, Discoloration and deodorization of palm oils.

In case the use of phosphoric acid is omitted in the pretreatment process according to the invention the process becomes similar to a conventional decolorizing process, and is obtained by the following What ^ steam refining process carried out after activated clay treatment, an extremely small discoloration effect, although the oil is discolored to some extent. In this The case is to obtain an end product that is decolorized to the same extent as oil that with phosphoric acid and activated sound according to the invention has been treated, necessary more than twice the amount to use activated sound, as is necessary according to the invention. Furthermore, the temperature must be higher are kept than in the method according to the invention.

In the method according to the invention phosphoric acid is used in an amount of 0.01 to 2.0% of the liquid oil of the palm oil type are added, it usually being sufficient to use the phosphoric acid in an amount of 0.02 to Use 1.0% of the crude oil.

The amount of activated clay used in the pretreatment process will vary depending on the properties of the crude oil used? variable. It is generally sufficient, about half that of the usual Use decolorization process necessary amount.

The use of phosphoric acid to refine oils in conjunction with an alkali in a Alkali refining process to react with phosphatides in the oil and the loss to reduce the amount of neutral oil that is entrained in the soap mass in the course of the neutralization process, does not give any explanation for the effect of the phosphoric acid used according to the invention, which affects the refining, palm oils, which hardly contain any phosphatides, are used. It can be clearly seen that the mechanism and the effect of the phosphoric acid used according to the invention, with no alkali materials are used, from the effect present in the alkali refining completely deviate. That The process of the invention is superior to the usual alkali refining processes, since it results in low losses result in neutral oil and good decolorization is achieved.

The refining process of the invention is economical because complicated measures and special equipment are not required and losses of neutral oil are substantially reduced, since oil of good quality can be obtained in a simple manner.
The following examples illustrate the invention.

B e i s ρ i e 1 1

The following four working methods were based on a raw palm oil with an acid number obtained in Sumatra of 635 applied.

(1) Treatment with phosphoric acid and activated clay together with steam refining (process according to the invention):

Phosphoric acid at a concentration of 85% was added at a ratio of 0.05% to the crude oil added and mixed for 30 minutes with stirring. Then 3% activated clay was added, and that Mixture was heated to 105 ° C for 15 minutes with continuous mixing: the activated clay was then removed. The oil obtained in this way was subjected to steam refining by blowing in superheated steam under a vacuum of 6.65 mbar absolute at 270 ° C. for 30 minutes, with an ordinary decolorizing machine was used.

(2) Treatment with activated clay together with steam refining without the use of phosphoric acid (comparative method):

Two crudes were made by a conventional decolorization method using 3% activated clay, one discolored at 105 ° C and the other at 150 ° C for 15 min. After the sound was removed were the oils of steam refining under the same conditions as described in (1), subject.

(3) The crude oil was treated with phosphoric acid and activated clay at the same time and then subjected to steam refining (comparative method):

0.05% phosphoric acid and 3% activated clay were simultaneously introduced into the crude oil and this was mixed! 5 m \ "t at! 05 ⁰ C. After the clay had been removed, the O! Among the same?" Conditions as described in (1), subjected to refining of the steam.

(4) Alkali neutralization, discoloration and deodorization (comparative method):

The crude oil was neutralized with the alkali of 14 ", and the neutralized oil was decolorized using activated clay in an amount of 3% at 105 ° C for 15 minutes. After the clay was removed, the oil was subjected to steam refining under the same conditions as described in (1).

The oils obtained by the above four procedures were measured for color using a Lovibond cell of 133 cm. The results are shown in the table below:

Table 1 Decolorization effect according to the applied refining process Refining process Color of the product *) Yield

yellow red (% of crude oil)

(1) 10 1.0 94.1

(2) discolored at

105 ° C 20 23 94.1

150 ⁰ C 15 1.5 94.1

(3) 10 1.5 94.1

(4) 10 U 92.0

*) Lovibond cell. 45

It can be clearly seen that the process of the invention (1) is superior to the procedures (2) and (3) and the alkali refining process (4) in the decolorizing effect with little loss of neutral oil is.

Example 2

0.20% phosphoric acid was added to a crude coconut oil having an acid number of 9.64 and

Mixed for 10 min with stirring, the temperature was increased to 105 ° C, 1% activated clay was added, and the procedure was continued as described in Procedure (1) of Example 1 after the clay

had been removed, the oil was ^{subjected to steam refining at 230 °} C. for 30 min

The color of the obtained oil was yellow 8 and red 1 J5 according to a Lovibond colorimeter.

A comparative product was made by pretreating with 1% clay (105 ° C, 15 min) alone and performing obtained by the same steam refining procedure. This product gave the color yellow 14 and red 2.7. To obtain a product with the same color as the product obtained according to the invention, it was necessary to use 3% activated clay and there was a 1.6% decrease in yield.

Example 3

Six samples of identical raw palm oil of the same quality were used in this experiment In the tests, amounts of 0.1%, 1% and 2% phosphoric acid and 3% activated clay were used and the heat treatment was carried out in experiments A, B and C according to the invention at 105 ° C. and in comparative experiments D, E and F at 121 ° C. The same constant process conditions were used

The results obtained are shown in Table II below. Table II

Sample A

Raw palm oil colour

(One inch Lovibond cell) acid number

40G / 25R 40G / 25R 40G / 25R 40G / 25R 40G / 25R 40G / 25R 7.14 7.14 7.14 7.14 7.14 7.14

Phosphoric acid treatment concentration (%) 85

Amount of acid versus oil (%) 0.1 temperature ("C) 50

Mixing time (min) 10

Active tone treatment Amount of clay (%) Temperature ("C) Mixing time (min)

Steam distillation Temperature ("C) Period (min)

Pretreated oil *) colour

(One inch Lovibond cell) acid number

End product ")

colour

(14 cm Lovibond cell) acid number

105 15

250 60

85 1.0 50 10

105

250
60

85 2.0 50 10

105

15th

250 60

85 0.1 50 10

121 15th

250
60

85
1.0
50
10

121

15th

250 60

30G / 12.4R 30G / 12.4R 30G / I3R 2OG / 2.8R 20G / 3R 7.20 7.20 7.21 7.30 732

85
2.0
50
10

121

15th

250
60

20G / 4.2R 732

lOG / l.OR lOG / l.OR 10G / 1.2R 20G / 2.4R 20G / 2.4R 20G / 3.6R 0.05 0.05 0.06 0.06 0.07 0.07

Footnote:

G - yellow; R - red

*) After treatment with phosphoric acid and active clay. **) After treatment with phosphoric acid, active clay and steam.

It can be seen from Table II that the pretreated oils of samples A, B and C according to the invention after Clay treatment had the darker color than samples D, E and F, since the former at 105 ° C and the the latter were treated at 121 ° C. Despite the obviously less favorable initial color of the pretreated oil, the oils finally refined in the steam treatment had the oils according to the invention Samples A, B and C after the steam treatment are extremely light in color compared with that of FIG Samples D, E and F.

The experiment proves the fact that, according to the invention, the carotenoids in the crude palm oil remain in the heat-sensitive state after the clay treatment at 105 ° C and are completely decomposed during the subsequent steam treatment, while the carotenoids in the comparative tests in the oil after the clay treatment at 121 ° C in be transferred to a heat-insensitive state, so that they are not decomposed by the steam refining. According to the invention, varying the amount of phosphoric acid between 0.1 and 2.0% has little effect on the color of the oil, while in comparison F ₁ in which 2% phosphoric acid was used and ^{heated to 121 °} C., the color of the end product was very dark . If even higher temperatures are used in the treatment with active clay, for example 177 ° Q, the subsequent steam refining does not result in the decolorization according to the invention, but even a deepening of the color of the end product.

The above examples show that the process according to the invention provides a significant decolorizing effect and also has the advantages of reducing the amount of activated activated Tone and improve the yield.

Example 4

Using 6 samples of raw palm oil of the same quality, the purification procedure was carried out carried out according to the invention under the conditions given in Table III below Colors of the crude and pretreated oil were measured using a Lovibond cell of 2 ^ 54 cm, and the color of the final product was determined using a 14 cm Lovibond cell. The results are in FIG Table III below

Table III Raw palm oil Color (Lovibond cell 2.54 cm)

Acid value

Phosphoric acid treatment Concentration,% Amount of acid, based on oil,% Temperature, "C Mixing time, min

Treatment with activated sound Amount of clay,% Mixing time, min Temperature, ° C

Steam refining temperature, ⁰ C duration, min

30G / 20R

(30G / 20R)

7.50

85 0.05 50 30

15th

80

90

100

UO

120

130

270 30

Table IV

Temperature during clay treatment, "C 80 90 100 110

120

Pre-treated oil ») paint (Lovibond cell 2.54 cm) Cs ..- «- .. ul

oaui VLaiu

End product ") color

(Lovibond cell 14 cm) acid number

3OG / 7.7R 3OG / 7.7R 3OG / 7.7R 30G / 6.5R 20G / 4.4R 20G / 2.5R

7 On 7 11 7 TC 7 ΊΛ 7 Ίΐ \ 7 CC

13G / 13R 10G / 1.0R lOG / l.OR lOG / l.OR 20G / 1.8R 20G / 2.0R

0.06 0.06 0.06 0.06 0.06 0.06

*) After treatment with phosphoric acid and activated clay. * ·) After treatment with phosphoric acid and activated clay and steam refining.

The results in Table IV above show that when the treatment was carried out with activated Clay in the range of 90 to 110 ° C, satisfactory results have been obtained.

1 sheet of drawings

Claims (1)

Claim: Process for the refining of crude oils of the palm oil type using phosphoric acid and subsequent addition of active clay at elevated temperature and subsequent steam refinery tion, characterized in that 0.01 to 2.0% phosphoric acid is added to a liquid oil of the palm oil type, the oil and the acid are mixed together with thorough stirring, the resulting mixture is mixed with activated clay while the temperature of the mixture increases a temperature in the vicinity of about 100 ⁰ C is increased, the mixture holds at this temperature for 5 to 30 minutes, this treatment being carried out so that the oil treated in this way does not have any significant discoloration and the characteristic see peaks of the absorption spectrum for /? - carotin in which crude oil remains essentially unchanged whereupon the clay is removed from the oil and the oil is simultaneously decolorized by steam refining and is deacidified.