FR2459828A1 - PROCESS FOR REFINING ANIMAL OR VEGETABLE OILS AND FATS - Google Patents

Abstract

A PROCESS FOR REFINING AN ANIMAL OR VEGETABLE OIL OR FAT CONSISTS OF: A) MIXING THIS OIL OR GREASE WITH AN AQUEOUS SOLUTION OF AN ALKALINE SUBSTANCE; B) SEPARATE THE INSOLUBLE MATERIAL FROM THE OIL OR GREASE OF THE MIXTURE OBTAINED; C) MIX DIRECTLY THE DEACIDIFIED OIL OR GREASE SEPARATED FROM STAGE B) WITH AN AQUEOUS SOLUTION OF AN ACID; IF NECESSARY DRY THE MIXTURE TO REMOVE THE EXCESS WATER; D) TREAT THE MIXTURE OBTAINED WITH AN ADSORBANT TO ADSORVE THE COLORING MATTER, IMPURITIES AND SALTS FORMED DURING STAGE C); E) SEPARATE ADSORBANT FROM OIL OR GREASE; AND F) TREAT OIL OR GREASE AFTER STEP E) BY WATER VAPOR DISTILLATION; A REFINED PRODUCT HAVING THE SAME QUALITY AS A CLASSIC REFINED PRODUCT IS OBTAINED WITH A GOOD EFFICIENCY AND ECONOMICALLY.

Description

The present invention relates to a method for

  refining oils and fats.

  Various processes have been developed to refine

  oils and fats. The pro-

  alkaline refining process which is an important process for refining oils and fats because it has many advantages over other processes. An important problem

  which has recently become more important in terms of pollution

  tion of the environment and material savings is that alkaline refining produces a significant amount of waste water. In the classic alkaline refining process,

  we put crude or degummed oils and fats of ori-

  animal or vegetable gine in contact with an aqueous alkaline solution. The free fatty acid of oils and fats reacts with the alkaline solution and the oils and fats are

  deacidified in the form of a soapstock consisting mainly of

  also fatty acid soap which is separated by centrifuga-

  tion as illustrated by diagram A below.

  Then mix and stir the deactivated oil.

  specified, after separation of the soap from the oil, with a quan-

  large amount of hot water to establish sufficient contact

between oil and hot water.

  The soap, which remains in the oil at a concen-

  around 100 to 1000 ppm depending on the nature and capacity

  cited from the centrifuge, goes into the liquid phase and is centrifuged again. This single wash is insufficient and more than two washes are necessary to completely eliminate the

oil soap.

  Diagram A Raw or degummed animal or vegetable oils and fats alkaline solution Y-aqueous deacidification water rejection treatment rosi I centrifugation --soapstock v-hot water mixing, stirring I centrifugation

iduary é--

  [, - hot water mixing, stirring / 1 centrifuge

waste water -

  décoloi Lgation stage of washing with water | - adsorbent ration i deodorization of refined oil The washing operation therefore produces a very

significant waste water.

  As this waste water contains a considerable amount

  maple of impurities such as soap and entrained oils, it cannot be rejected without having treated it by flotation

  pressurization or with activated sludge. So the treatment installation

  waste water requires a significant investment.

  The centrifuge or mixing and mixing apparatus

  tation required by the washing operation is very expensive and the number of these devices depends on the number of successive washing operations. Two successive washing operations require two sets of devices. The washing operation carried out in oil refineries alone requires large investments and is a major concern for manufacturers. It is undesirable to use such a large amount of water for reasons of material savings and this large amount of water is the first element to be reduced. The classic process of

  alkaline refining becomes increasingly disadvantageous.

  The subject of the invention is an economical process for refining oils and fats a process for refining oils and fats which eliminates the washing operation and thus avoids the production of waste water and the pollution of the environment which s 'then; and a process for refining oils and fats which makes it unnecessary to invest in water washing devices for oils and

  neutralized grease and waste water treatment.

  According to the process for refining oils and greases of the invention to achieve the above-mentioned objectives, as well as others, the washing operation is eliminated after the separation of the

  soapstock neutralized oils and fats.

  The preferred embodiment of the invention will main-

holding be described.

  The invention relates to a process for refining oils.

  and animal and vegetable fats and more particularly a pro-

  sold to refine crude oils and fats of animal and vegetable origin or oils and fats that have been subjected to a conventional pretreatment. The invention is characterized by the fact that these oils and these fats are deacidified with an aqueous solution of alkaline compounds, the soapstock thus formed is centrifuged from the deacidified oils and fats, these oils and these deacidified fats are mixed directly with a aqueous acid solution without washing the deacidified oils and fats with water after separation of the soapstock, the mixture obtained is dried if necessary, the mixture is treated with an adsorbent and treated

  oils and fats by steam distillation.

  The Applicant has studied the processes for refining the oil, eliminating the washing stages after deacidification of the conventional alkaline refining process, in order to avoid production.

  of waste water, and the invention is the fruit of this research.

  Diagram B Animal or vegetable oils and fats degummed | Aqueous alkaline solution deacidification centrifugation --soapstock aqueous acid solution mixing, stirring acid treatment stage Adsorption discoloration deodorization refined oil As shown in diagram B, the refining process

  animal and vegetable oils and fats of the invention sup-

  takes precedence over the washing stage of the conventional alkaline refining process and replaces this washing stage with a simple acid treatment stage. So the refining process itself is greatly simplified. As the centrifugal separation of oils from water

  washing which is carried out in the conventional washing stage is sup-

  awarded in the refining process of the invention, the machine costs

  centrifuge is unnecessary and there is no production

waste water.

  The process for refining oils and fats from

  the invention comprises the following stages -

  1) treatment of oils and fats with an alca- solution

  line (deacidification), 2) separation of insoluble matter, 3) treatment of oils and fats with an aqueous solution of acids, 4) treatment of oils and fats with an adsorbent (discoloration), 5) treatment of oils and fats by distillation at the

water vapor (deodorization).

  The special features of these stadiums are

described below.

1) Alkaline treatment.

  This stage constitutes a classic deacidification stage.

  tion which speaks for itself. If desired, the oils and fats of animal and vegetable origin are subjected to a pretreatment such as physical removal of the impurities from the oil by filtration or sedimentation, degumming with water from acids, alkalis and

  other chemical agents. We can also classically

  a conditioning of gums with acids such as acid

  phosphoric. This preprocessing stage is optional.

  To carry out the alkaline treatment, the oils and fats are brought into contact with an alkaline aqueous solution to neutralize the free fatty acid, to saponify, hydrate and coagulate the gummy substance and discolor the coloring matter of the oils and fats. Alkaline compounds such as caustic soda and soda ash are generally added to the oil. Soaps and the coagulated gummy substance are suspended in the mixture under

form of an insoluble matter.

  2) Separation of insoluble matter.

  This stage consists of the commonly used stage of the pro-

  yielded classic alkaline refining. The insoluble matter formed in the preceding stage of alkaline treatment in the form of a soapstock is removed from the oil by centrifugation. This soapstock consists mainly of soap and contains neutral oil entrained and

  impurities such as the gummy substance.

  3) Treatment with an aqueous solution of acids.

  In the conventional alkaline refining process, the oil is washed with a large amount of water after stage 2) (hereinafter this oil is called separate deacidified oil). The characteristic of the process of the invention is that stage 3) is carried out directly

  without washing the separated deacidified oil with water.

  As previously stated, the separated deacidified oil generally contains soap at a concentration of 100 to 1000 ppm and a small amount of impurities such as mucilage. The separated deacidified oil is treated with an aqueous solution of acids in this stage 3) to hydrolyze the soap contained in the oil and form the free fatty acid and salts. Impurities such as mucilage in small quantities in the oil coagulate simultaneously in the oil in the form of an insoluble matter. So the free fatty acid thus formed dissolves in the oil and the impurities and salts remain

  in oil as an insoluble matter.

  The acids which are used in this stage are organic or mineral acids such as hydrochloric acid, sulfuric acid, phosphoric acid, oxalic acid, acetic acid, acetic anhydride, citric acid and tartaric acid or a combination of more than two types of these acids. Phosphoric acid is most suitable when considering its influence on the constituent material of the apparatus and from the economic point of view. These acids are added to the separated deacidified oil at an appropriate concentration and mixed and stirred at a temperature between

  ordinary temperature and 1000C for several seconds more

  hours. If phosphoric acid is used, the concentration of the aqueous solution is approximately 75-857% and, if citric acid is used, it is approximately 73-80X. We can also use

  lower acid concentrations in this step but the concen-

  The tration of the acid solution is preferably as high as possible with regard to the subsequent step 4. The extent of this

  interval of contact times is due to differences in efficiency

  cited from the contact that is obtained according to the mixers. In short, it is necessary to establish regular and intimate contact between acids and soaps or mucilages for their reaction to be rapid and sufficient. It is also possible at this stage to use the installation or the apparatus used in the alkaline refining process for bringing the oils into contact with an alkali or with water. The contact between acids and soaps or mucilages can be accelerated by use

of a homogenizer.

  The quantity of aqueous acid solution which is mainly added is calculated from the quantity of acid necessary to decompose the soap contained in the separated deacidified oil and, to establish it, the quantity d '' impurities such as mucilage in the oil. When the soap content in

  the oil is 1000 or 100 ppm, the required amount of phos-

  85% phoric is about 380 or 38 ppm and, if using acid

  acetic acid at 10O0, approximately 197 or 19.7 ppm are necessary to decompose

  apply the soap. We can also take into account the amount of impure-

  your. If necessary, the oil is dried after this stage of treatment in an appropriate dryer to remove excess water.

  oil before the next stage treatment.

  4) Treatment with an adsorbent (discoloration).

  This stage is a classic bleaching operation. The oil which has been treated with acids in stage 3) or the oil which has been dried after the treatment of the oil is treated with an adsorbent such as activated clay or activated carbon.

  stage 3). Impurities remaining in the oil, such as mucus

  The salts formed by the reaction of the acids with the soaps and the coloring matter of the oil are almost completely adsorbed on the adsorbent and removed from the oil. The stage of treatment, the conditions and the apparatus of the stage can be used in this stage.

classic discoloration.

  ) Treatment by distillation with water vapor (deodorization). This stage is also a classic deodorization treatment. The fatty acid which has been released by the acid treatment in stage 3) is entirely removed from the oil by distillation with the odorous material. At the same time the coloring matter of the oil is broken down by heat and the oil takes on a color

  Claire. As impurities such as mucilage were previously

  completely removed from the oil, the oil does not color due to the presence of impurities. The conventional process, apparatus and conditions for distillation by

water vapor.

  As shown in the previous description of the

  preferred embodiment, the invention has the effects and advantages that the washing stage of the conventional alkaline refining process is eliminated

  and that therefore coding apparatus such as centrifuges

  geurs are useless. Impurities and soaps are treated with an acid in the separate deacidified oil, and the oil is removed in the

  conventional washing process and these impurities and soaps are whole-

  removed from the oil in subsequent stages of discoloration and

deodorization.

- 2459828

  To treat the oil with an aqueous acid solution according to the invention, only one mixing device is necessary in a series of oil refining devices. Two sets of devices such as a centrifuge and a mixer in a series of conventional oil refining devices are required to perform two washes during the washing stage. So the process for refining oils and fats of the invention is much better than the process

  classic alkaline refining from an economic point of view.

  The reduction in the cost of equipment was estimated at over 100,000,000 yen in 1979 due to the elimination of

  washing stage equipment and installation such as centri-

  runaways and mixers. This quantity is calculated for a raf-

  Japanese oil refinery with an average capacity of 200 tonnes

  per day. In addition operating costs such as operating costs

  operation and maintenance of the equipment as well as the costs of

  fixed assets such as surface area and buildings that

  cut these devices, are deleted. Therefore the process of the invention is of considerable economic interest compared to the usual process.

  The process of the invention does not produce residual water.

  dual and is a clean process avoiding pollution of the environment-

  is lying. The method of the invention makes it possible to reduce consumption

  of water, the thermal energy of heating the washing water and energizing it

  operating the devices used in the washing stage.

  This process is of great interest in the refining industry.

  swimming oils. The quality of refined oils and fats pro-

  picks according to the process of the invention is practically equal to that

  obtained in the alkaline refining process and the yield is higher

  laughing. If we remove the washing operation of the conventional alkaline refining process and increase the amount of asborbant for

  remove soaps, impurities and coloring matter that remain

  in the oil, without performing an oil acid treatment

  deacidified, such a process has the same advantage that is the sup-

  washing stage pressure as the process of the invention. However, such a process requires the use of a very large amount of adsorbent compared to the process of the invention. Therefore a significant amount of oil is lost with the adsorbent and the increase in the cost of the adsorbent and the decrease in oil yield cancel the advantage of eliminating the washing stage. Such a process has no economic interest and is much inferior to the process

of the invention.

  The process of the invention can be applied advantageously to the refining of vegetable and animal oils and fats of all kinds, such as soybean oil, rapeseed oil,

  rice oil, corn oil, cottonseed oil, tour oil

  nesol, safflower oil, sesame oil, peanut oil, -

  palm oil, coconut oil, linseed oil, lard, beef tallow, mutton tallow, fish oil and oils

and marine animal fats.

  The invention will be better understood on reading the examples

following nonlimiting.

Example 1.

  Soybean oil is treated according to the conventional alkaline refining process. The deacidified oil is obtained separated by separation of the soapstock from the oil with a centrifuge. We divide

  the oil in four samples used in the following tests

  touts. The characteristics of the separated deacidified oil are shown

in the table below.

  Test 1 (process of the invention (1)).

  40 ppm by weight of 85% phosphoric acid is added to the separated deacidified oil and the acid treatment is carried out by stirring the mixture for 5 minutes at 800C. Then we add

  the oil treated with acid, 0.3% by weight of activated clay and one deco-

  lore the oil under reduced pressure at 1050C for 15 minutes and the activated clay is separated from the mixture. The discolored oil thus obtained is subjected to vacuum deodorization at 2500C for 45 minutes. We

thus obtains a refined oil.

  Test_2_ (process of the invention (2)).

  This test is carried out under the same conditions as in test 1, except that the amount of phosphoric acid is

80 ppm.

  Test 3 (comparative test (1): conventional process) The separated deacidified oil is washed with 207. hot water relative to the oil and centrifuged. After two washes we

  discolored and deodorized under the conditions described in test 1.

  Test 4 (comparative test (2)). The deacidified oil separated without treatment is bleached and deodorized directly, under the conditions described in test 1

by an acid or washing.

  The characteristics of the oil in each stage of

  tests 1 to 4 are shown in the table.

  As the results of the tests shown in the table show, the refining process of the invention (tests 1 and 2) makes it possible to obtain a refined oil having practically the same

  characteristics and the same quality as the oil obtained according to the pro-

  conventional yield (test 3) by simple treatment with phospho- acid

  risk of separated deacidified oil without washing with water. Like the

  conditions of discoloration and deodorization of the process of the invention

  tion can remain the same as those of the conventional process, they have no effect on the yield of refined oil. The method of the invention is superior to the conventional method by the yield of refined oil because in the latter neutral oil is lost by

wash water entrainment.

  When the separated deacidified oil is bleached and deodorized directly without acid treatment and without washing

  water (test 4), soaps and phospholipids are not enough

  fisely eliminated. The quality of the refined oil is therefore poor.

  Tests show that it is necessary to use 0.87. of activated clay, which is more than twice the amount of clay required by the process of the invention, to improve the quality of the oil refined in test 4 and bring it to the quality of oil obtained in tests 1 and 2. The increase in cost

  of the oil refining of this process compared to the process of the

  vention is around 1,000 yen per ton of oil.

Example 2.

  Colza oil is treated conventionally with an alkaline solution and the soapstock is centrifuged. 431 ppm by weight of a 30% aqueous solution of citric acid is added to the separated deacidified oil having an acid number of 0.06, a soap content of 205 ppm and a phospholipid content of 283 ppm . The mixture is stirred for 30 minutes at 50 ° C. and then 0.6% by weight of activated clay is added to the oil and the oil is discolored at 105 ° C. for 15 min. The activated clay is separated from the oil. The oil is deodorized under reduced pressure at 250 ° C. for 45 minutes. A refined oil is thus obtained having an acid number of 0.05, a color of 6YxO ,?

  and a phospholipid content of 5 ppm. The quality of the oil

  fineness is practically the same as that of conventionally refined oil.

Example 3.

  Matt oil is deacidified according to the conventional process.

  alkaline treatment sique and the soapstock is centrifuged to obtain

  the separated deacidifying oil. 604 ppm by weight of a solution are added.

  20% aqueous hydrochloric acid with separate deacidifying oil

  with an acid number of 0.08, a soap content of 990 ppm

  and a phospholipid content of 368 ppm. The mixture is stirred for

  for 5 minutes at 80 C. 0.6% by weight is then added to the oil.

  of activated clay and the oil is discolored at 105 ° C. for 15 minutes.

  After separating the activated clay from the oil, the oil is deodorized under reduced pressure at 260 ° C. for 60 minutes. A refined oil is thus obtained having an acid number of 0.07, a color of 6YxO, 6R

  and a phospholipid content of 13 ppm. The quality of the oil

  finde is practically the same as that of conventionally refined oil.

Example 4.

  Beef tallow is deacidified according to the al-

  conventional hug and the soapstock is separated from the tallow to obtain a separate deacidified tallow having an acid number of 0.06, a soap content of 205 ppm and a phospholopid content of 54 ppm. 45 ppm by weight of acetic acid is added to the tallow at 98% and the mixture is stirred at high speed with a Dispermill (manufactured by Hosokawa Iron Works) for 30 seconds at 90 C. The oil is added 2% by weight of activated clay and discolored under reduced pressure at 120 C for 30 min. The oil is deodorized under vacuum at 250 ° C. for 90 minutes. A refined oil is obtained having an acid number of 0.02, a color of

  1Y x 0.1 and containing traces of phospholipids.

  The refining process of the invention makes it possible to eliminate

  ner the stage of washing with water after deacidification and separation

  tion of the soapstock of the deacidified oil of the conventional alkaline refining process as clearly shown in the previous examples and makes it possible to obtain with a good yield a refined oil having the

  same quality as conventionally refined oil.

  As the acid treatment method of the invention involves little cost compared to the advantage which is the elimination of the washing stage, the method of the invention is much superior to the conventional method. The refining process of the invention does not form waste water and allows the consumption of useful water to be saved, which constitutes a very significant advance in the manufacturing industry.

oil refining.

  Of course various modifications can be made.

  those skilled in the art to the devices or processes which come

  to be described only as non-limiting examples without going out

from the scope of the invention.

BOARD

  > try! 1 2 3 4 method of comparative test method comparative test the invention the invention (1)

(2) (2)

  characteristic (1) (2) conventional process (2) oil Acid index 0.04 deacidified soap (ppm) 211 separate phospholipids (ppm) 118 acid-treated with acid * oil phosphoric acid phosphoric acid 0 , 06 without washing washed with soap (ppm) (40 ppm) (80 ppm) 3 or treatment with phospholipid water (ppm) sn (8 22 with acid; without washing without washing oil acid number 0.08 0 .08 0.07 0.07 huióloe it discolored color 30Y x 6.0R 30Y x 6.0R 30Y x 6.2R 40Y x 6.6R soap (ppm) unidentified unidentified unidentified 11 acid number 0 .0.3 0.03 0.03 0.03 y 2, Y x, 2R 3x o, 3R color oil 2.2 x 0.2R 2.3Y x 0.2R 3Y x, 3R 4Y x 0.4R deodorized phospholipids (ppm) 12 13 18 43 aroma good good good bad for ijI II hot oil NO Co Co

Claims (2)

R E V E N D I C A T I 0 N S CLAIMS   1. Procedure for refining an animal or vegetable oil or fat, characterized in that it consists of: a) mixing this oil or fat with an aqueous solution of an alkaline substance; b) separating the insoluble matter from the oil or the fat from the mixture obtained;   c) mix the oil or separated deacidified fat directly   level b) with an aqueous solution of an acid; d) treating the mixture obtained with an adsorbent to adsorb the coloring matter, the impurities and the salts formed in stage c); e) separating the adsorbent from the oil or fat; and   f) process the oil or fat after stage e) by distillation water vapor.   2. Method according to claim 1, characterized in that after stage c) and before stage b) the mixture obtained is dried to remove excess water.