DE4002161A1 - Extracting oils and fats - from exhausted adsorbent with supercritical carbon di:oxide - Google Patents

Abstract

In extn. of oils and fats, esp. of paraffinic and glycidic oils and fats from exhausted adsorbents, e.g. fuller's earth, C and/or SiO2 gel, the fats and/or oils are extracted with supercritical CO2. Extn. is carried out at 31-100 (35-75) deg. C and/or the sepn. temp. is 0-100 deg. C; the pressure is 200-750 (300-500) bars and/or the sepn. pressure is 32-120 bars. Addtional extractants, e.g. NO and/or ethane and/or propane, may be used. The extracted fats and/or oils are sepd. from the CO2, eg. by pressure release, and the CO2 is re-used, pref. in a closed cycle, for extn. of fuller's earth. ADVANTAGE - Good quality oils and fats, suitable for food, are released, and the adsorbents can be re-used. Ext. is controlled so that only neutral fats are extracted, leaving free fatty acids and other polar substances in the fuller's earth.

Description

The invention relates to a method and an apparatus for Extraction of adsorbents that are used for extraction or Refining fats and / or oils, especially from vegetable materials, or also for brightening Mineral oils were used. The device is included a pressure-resistant extraction container for extraction the oils or fats from the adsorbents using a Solvent, with a compressor to provide the desired extraction pressure, with a heater for Providing the desired extraction temperature and with at least one separator to separate the fats or oils provided by the solvent.  

When processing or refining crude oils are usually adsorbents, such as bleaching earth, pebbles gel, coal or mixtures thereof. The main radio tion of the adsorbents is the brightening of the Verede used oil or fat. Even in the mineral oil These adsorbents are used to brighten the industry paraffinic oils to be processed there. Here usable oils and fats remain in the adsorbents back. To return the oils or fats from the adsorbents different methods are used.

The magazine "Fette, Seifen, Anstrichmit tel ", special issue 1981, 83rd year, page 543 ff., the discussed below:

• - Extraction of the oil / fat from the bleaching earth under Ver use of hot water and surface-active reagents zien;
• - Integration of the bleaching earth in the extraction process for oily seeds / press cake;
• - Extraction of the bleaching earth by using a po laren or non-polar organic solvent.

The advantages and disadvantages listed in this publication of the procedures listed relate to required or unnecessary security measures, usable of the extracted oils or fats and for disposal Availability of the resulting bleaching earth waste.

With all listed methods for the extraction of The resulting bleaching earth waste cannot like bleaching earth be used.

The object of the present invention is the After to avoid parts of the listed state of the art  and in particular a method and an apparatus beat that allow high quality oils or fats from the bleaching earth to be extracted or other adsorber to remove the bentien and the bleaching earth as far as to make it reusable.

This is for a method according to the invention by the characterizing part of claim 1 specified features reached while a device according to the invention results from the features in the characterizing part of claim 9.

Appropriate process variants or embodiments are defined by the features in the subclaims.

According to the extraction of the used adsor performed with supercritical gases. The we Significant feature of the process is the extraction of oil and fat-containing adsorbents above the critical Temperature (31.1 ° C) and / or critical pressure (73.8 bar). If these two parameters are sufficiently above the critical values, the gaseous carbonic acid converted to a supercritical, fluid state, in which the extractant (under the appropriate Para meters) loaded with the extract (i.e. with the one in the ge needed adsorbent included oil and fat). In the Relaxation of the supercritical gas separates extracted substance from the extractant (which in the supercritical state acted as a solvent te), fails and can now be removed; so you can by changing the extraction parameters not just the Degree of extraction but also affect the selek extraction activity. On the other hand, you can also go through the setting of the relaxation parameters, d. H. Pressure and Temperature, the extract gradually precipitate.  

Due to extensive experi mental work shows that fats and / or oils from adsorbents using supercritical Koh Lentic acid can be recovered so advantageously that the recovered fats and / or oils to edible fat or oil can be processed. In addition, the extract ten adsorbents reusable. This can go back obtained adsorbent ver both with unused adsorbent mixes as well as used alone for refining crude oil be det.

This allows both those involved in the refining of the crude oil waste products are significantly reduced as well as the economic aspects of refining Oils and fats can be changed for the better.

It is particularly advantageous that the use of the over critical or supercritical carbonic acid process can be technically controlled so that mainly one Extraction of neutral oil takes place during refining has remained in the used adsorbent. Stick to it preferably free fatty acids and other polar substances in the bleaching earth back.

The extraction of the used adsorbent is in tempera range from approx. 31 ° C to approx. 100 ° C, in particular 35 to 75 ° C, feasible with favorable results.

The prints that can be used for the extraction are in one Range from approx. 200 to approx. 750 bar. Especially in the Be ranges from 300 to 500 bar are already extremely positive Results have been achieved. The separation pressure is 32 up to 120 bar.  

Overall, this has resulted in high extrac tion pressures and extraction temperatures are particularly good deliver results. As a result, temperatures can also drop above 80 ° C and pressures above 750 bar deliver optimized results, but technically realizable limit values and economic considerations note.

To extract the process to certain properties To adjust render fats or oils, it can be advantageous be the supercritical carbonic acid extra extract add agents. For this, e.g. B. nitrogen oxides and / or ethane and / or propane can be used.

The oil and / or fat extracted from the bleaching earth can especially after a further refining, as Spei sea fat or oil can be used.

The gaseous carbonic acid freed from oil or fat becomes reused in a closed loop, what, how also for all other described process features, both waste disposal and environmentally friendly as well brings with it economically positive aspects.

A device for extracting adsorbents, esp especially for performing the method according to the claims chen 1 to 8, according to the preamble of claim 9 equipped with an extraction container that can hold min at least one feed line or at least one discharge line tion for supercritical carbonic acid, the Extraction container an insertable or executable in this Batch container can hold the one to be extracted Contains adsorbent. The extraction container is also included at least one essentially gas or pressure tight  sealable closure provided. This makes it possible in quick order with batch containers to extract render introduce bleaching earth into the extraction container, to extract and remove after extraction nen.

The batch container is provided with walls that consist at least partially of sintered metal areas. The supercritical Carbon dioxide are introduced into the batch container and through the adsorbent to be extracted who the.

So that the whole, if possible, in the extraction container introduced supercritical carbonic acid to extract the Adsorbents can be provided, it is advantageous is responsible for fitting the batch container, which the batch container with its outer walls sits in the extraction container that he essentially sealingly rests on the inner walls.

Are on the inner wall of the extraction container and / or umlau on the outer wall of the batch container fende seals provided on the opposite Sealing the wall of the extraction or batch container the efficiency of the device or of the process can be further increased.

Because a tight fit of the batch container at Insert the batch container into the extraction container Can cause problems, it is advantageous, at least that Outer wall of the batch container and the inner wall of the Extraction container to match each other in the direction of insertion of the batch container tapered or the like  leave, because this creates a margin, whereby the container walls or the circumferential you when importing or exporting the batch container be spared. The taper does not have to be uniform but can be especially in the area of seals, the on the outer wall of the batch container or on the Inner wall of the extraction container are available, ver be changed. This will make the seals during the process of inserting the batch container into the extract tion container not rubbed against the walls, but in their final seat, e.g. B. by the weight of the Batch container and the adsorbents, lie tight. This also makes it possible to make batch containers shorter Exchange time, since the batch containers no longer wear off must be adjusted exactly to the extraction container before being lowered into them.

The batch container can also predominantly be solid in the extract tion container installed and provided with means, to supply the adsorbents to be extracted or the Ex tract and remove the extracted adsorbents. Here This saves time on the one hand and on the other the possibility remains, for. B. in accidents (constipation or the like.) to replace the batch container. As a transport means can e.g. B. Transport screws or the like. Provided to avoid material jams can be parental within the batch container To provide agitator or the like. To avoid pressure drop, is the installation of one or more pressure locks special advantageous due to the material in the extraction process introduced and removed from the process can be.  

For further rationalization, it can be advantageous also the extraction container with means of transport for Equip transport of the adsorbents, whereby the Ver driving sequence additionally continuous or semi-continuous can be designed. Here the Extrak tion container, of course, also directly with extract adsorbents are filled or emptied by it, so that a batch container is no longer required.

It is necessary for precise control of the extraction process manoeuvrable, the heater directly in the thermal Contact to the extraction container or to the batch container to arrange. This can be done either in the extraction container or a pipe system is installed in the batch container, through which the liquid is passed, its tempe rature is controlled. To ver the temperature control better, it is also possible to pre-induction heating watch. Through this it is possible to get to Tempe faster rature changes to react, making a significant change improved process management is made possible.

By the method discussed above or the first It is possible to use about 80 to 90% of the absorbed by the used adsorbents To recover oil or fat, the accumulation of oil to significantly reduce gene adsorbents and the environment in addition of vapors from other processes keep organic solvents free.

The invention is un hereinafter based on examples ter reference to the accompanying schematic Dar positions explained in more detail. This will have other advantages and features of the present invention. The Tables listed document the advantageous We  Kung the device according to the invention and the fiction according to the procedure. Show it

Figure 1 is a schematic representation of a basic device for performing the inventive method. and

Fig. 2 shows a longitudinal section through an extraction container according to the invention.

The apparent from Fig. 1, generally identified by the reference numeral 10 device for extracting oils or fats from adsorbents is with an Ex traction tank 12 , a first separator 14 , a second separator 16 , a buffer tank 18 and a compressor, in particular a membrane compressor 20 , permitted. The individual components are connected to each other via pressure-resistant lines. The gas flows or the pressures in the individual device components are controlled via valves 21 a to i. By using several separators 14, 16, it is possible on the Steue tion of temperature and pressure in the individual from separators 14, 16 selectively deposit oils or fats and / or organic solvent-specific. The components marked with TI and PI refer to pressure or temperature measuring or control devices. The buffer tank 18 can be used to provide or to receive missing gas quantities or excessive gas quantities. The compressor 20 compresses the carbonic acid in order to produce the desired supercritical or supercritical state. Via the valve 21 f, the device 10 can be supplied with fresh or additional carbonic acid. A bypass to the compressor 20 can be set up by opening the valve 21 g. The valves 21 a, 21 b, 21 c and 21 d are intended on the one hand to prevent a reflux from occurring, and on the other hand to ensure that the pressure desired for components 12 , 14 , 16 and 18 is kept relative to the other components can be. The substances separated from the carbonic acid can be drawn off via the valves 21 h and 21 i.

The function of the schematic arrangement according to FIG. 1 will be briefly explained below.

After to be extracted in the extraction adsorbents container has been filled 12, in Extraktionsbe container 12, a clean atmosphere is produced which we sentlichen the solvent from the "supercritical carbon acid" is. Before the filling process, the valve 21 a and at least the valve 21 e were usefully closed in order not to flood the entire system with air. For this purpose, an additional valve could also be provided between the extraction container 12 and the compressor 20 .

After the adsorbents are introduced together with the batch container 30 into the extraction container 12 , supercritical carbonic acid (CO ₂ ) is introduced via the compressor 20 and has a desired pressure between approximately 250 and approximately 750 bar, in particular 300 to 500 bar . The pressurized carbonic acid is brought either before or in the extraction tank 12 to a desired temperature between 30 and 80 ° C, in particular between about 35 and about 75 ° C, the desired supercritical or supercritical state of carbonic acid to manufacture. In this state, the supercritical or supercritical carbonic acid is able to preferentially remove the fats or oils from the adsorbents. The Extraktions temperature can be controlled by the Extraktionsbe container 12 is supplied with a liquid, the tempera ture is controlled via the sensor TI of the extraction container 12 con. An induction heater would be particularly useful here, as it enables temperature control to react quickly and function exactly.

The solvent extract mixture, which leaves the Extraktionsbe container 12 , is introduced via the valve 21 a in the first separator 14 . In the first separator 14 there are different temperature and pressure conditions, so that the carbonic acid separates at least part of the substances dissolved in it. The separated substances can be drawn off via the valve for 21 hours.

The carbonic acid can now be fed via a further valve 21 b to a second separator 16 , in which other temperature and pressure conditions also exist. Here, too, other substances dissolved in the carbonic acid can be separated.

Depending on the desired process variant, further separators could be arranged behind the second separator 16 . By controlling the temperature and the pressure in the separators, certain fats, oils or other ingredients from the carbonic acid can be selected in the differently conditioned separators 14 , 16 , etc. and via valves 21 h, 21 i, etc. in storage containers or be subtracted for further refining. Here it makes sense to provide bypasses for most or for each separator in a system with several separators, since the function of the system can be varied in many ways, e.g. B. by setting different separation temperatures and pressures in the individual separators.

The present after the almost complete deposition of solutes carbonic acid c via the valves 21 and 21 e again supplied to the compressor 20, where again the pressure of the carbon dioxide is re-set to enable the carbon dioxide to the desired supercritical state. Already here the carbonic acid, if desired, could contain additives of organic solvents.

In this way it is possible in the extraction vessel 12 from the bleaching earth according to the set extraction pressure and after the set temperature of extraction between 80 and 90% (or more) of the dissolve out in the adsorbents retained fats or oils and recover it.

In Fig. 2 an embodiment of an inventive extraction container 12 can be seen. Via a feed line 44 a is through a closure 40 of the Ex traction container 12 supercritical carbonic acid, if necessary with additives of organic solvents introduced into the extraction container. The desired extraction temperature is set by introducing liquid speed, in particular water, in the direction of arrow 42 a into a heating line in the outer wall of the extraction container. The temperature of the liquid introduced is carefully controlled. After the liquid has warmed the container 12 , it is in the direction of the Pfei les 42 b again out of the heating line 38 of the Extraktionsbe container 12 . In the extraction container 12 itself there is a batch container 30 which contains the bleaching earth to be extracted. The batch container 30 can be inserted into the interior of the extraction container 12 via the opened closure 40 of the extraction container 12 . Seals 34 on the closure 40 of the extraction container 12 ensure that neither pressure nor gas losses can occur during the process.

The introduced into the extraction container 12 überkriti cal or supercritical carbonic acid is via a Sin termetallkörper 39 on the batch container 30 in the Chargenbe container and passed through the adsorbents to be extracted. Seals 36 on the outer circumference of the batch container 30 ensure that the supercritical carbonic acid cannot flow unused through the extraction container, but must flow almost completely through the batch container 30 and thus the adsorbents 32 and is available for the extraction process.

The supercritical carbonic acid, which leaves the batch container 30 via the sintered metal plate 39 a, is loaded with substances from the adsorbents. The supercritical carbonic acid now leaves the extraction container 12 via the derivative 44 b.

The supercritical carbonic acid is then separated from the fats or oils dissolved in the adsorbents 32 into the separators 14 , 16 ,. . . initiated.

The process listed here or the device 10 shown here make it possible, on the one hand, to obtain a high yield of high-quality, recyclable oils or fats and, at the same time, to use the extracted adsorbents 32 again for refining crude oil.

In the following, the performance of the proposed method or the proposed device 10 is documented on the basis of some tables.

example 1

Table 1 documents an attempt at bleaching earth extraction which has been used to refine soy fat. The weight of used bleaching earth to be extracted was 400 g, the extraction pressure was 500 bar and the extraction temperature was 45 ° C. The separation pressure was 55 bar and the separation temperature 25 ° C. In the individual columns, the following is indicated (from left to right): extraction time intervals, sum of the extraction time intervals, the amount of extract per extraction time interval, the sum of the extraction amounts based on the sum of the extraction time, the oil or Fat yield in%. The fat yields were given in%. This information relates to the yield obtained by extraction with diethyl ether at the boiling point of ether. The total fat content of the used bleaching earth used was then 38.6%. The amount of CO ₂ provided for the extraction for each individual extraction time interval, the sum of the amount of CO ₂ provided based on the total elapsed _{extraction time} and finally the size m _Lsp , which relates to the per hour and per kg The amount of carbon dioxide (CO ₂ ) used to weigh the bleaching earth. This column division applies to all the following tables.

Table 1

The extracted fat contained 9% free fatty acids.

Example 2

In Table 2 below, a sample was again taken extracted on bleaching earth of 400 g. It was an extra tion pressure of 500 bar and an extraction temperature of 70 ° C used. The separation pressure was 55 bar and Separation temperature 25 ° C.  

Table 2

The extracted fat contained 12% free fatty acid.

The comparison of Examples 1 and 2 clearly shows that

• a) the higher extraction temperature the total extraction time shortened (6.82 h at 70 ° compared to 10.58 h at 45 ° C) and at the same time results in a higher amount of extract (83.7% compared to 78.58%)
• b) at the same time the extracted amount of free fatty acid is higher at 70 ° C than at 45 ° C.

Example 3

A test with a weight of bleaching earth of 200 g is documented in Table 3. An extraction pressure of 300 bar and an extraction temperature of 70 ° C were used here. The separation pressure was 60 bar and the separation temperature was 25 ° C. Table 3 clearly shows that at an extraction pressure of only 300 bar, the total extraction time for 83.08% extraction yield was now 14.07 h, ie more than twice as long as at an extraction pressure of 500 bar (example 2). The M _{Lsp also} increased to 17.94 compared to 6.06 and 6.67 respectively - Examples 1 and 2.

Table 3

Example 4

In Table 4 below is a bleacher Weighed 400 g at an extraction pressure of 500 bar and treated at an extraction temperature of 70 ° C the. The separation pressure was 60 bar and the separation temperature temperature 25 ° C. The bleaching earth that was used here was  a mixture of bleaching earth and activated carbon in the ratio 2: 1, like such mixtures often for some oils and fats be used. This mixture was previously used for bleaching used by coconut fat. The total fat content used The adsorbent mixture before extraction was 44.1%.

Table 4

The extracted fat had 4.2% free fatty acids.

As can be seen from the tabulated experiments, with increasing extraction pressure and increasing extraction achieve temperature-improved extraction results.

Example 5

In a further experiment, the bleaching earth / activated carbon mixture, which had been used to refine coconut oil, was extracted at 40 ° C and 300 bar. The separation pressure was 60 bar and the separation temperature was 25 ° C. After an extraction time of 12 hours and an M _Lsp value of 44.0, only a total yield of 78% fat was obtained. However, this fat contained only 2.1% free fatty acids.

Examples 4 and 5 once again illustrate that the yield, extraction time, the M _Lsp value and, last but not least, the selectivity of the extraction can be decisively influenced by the extraction parameters.

The extracted adsorbents were used in all experiments used again for bleaching experiments. The bleaching activity was between 80-95% for all reuses.

Claims (19)

1. Process for the extraction of oils and fats, in particular for the extraction of paraffinic and glycidic oils and fats from used adsorbents, such as bleaching earth, coal, silica gel and mixtures thereof, characterized in that the fats and / or contained in the adsorbents Oils are extracted by carbon dioxide in a supercritical state. 2. The method according to claim 1, characterized records that the extraction at temperatures of approx. 31 ° C to approx. 100 ° C, especially 35 to 75 ° C  is and / or the deposition temperature between 0 ° -100 ° be wearing. 3. The method according to any one of claims 1 or 2, characterized characterized in that the extraction at Pressures between approx. 200 and approx. 750 bar, especially 300 up to 500 bar, and / or the separation pressure is between 32 and 120 bar. 4. The method according to any one of claims 1 to 3, characterized characterized in that during the extraction too additional extraction agents. 5. The method according to claim 4, characterized records that as an additional extractant Nitrogen oxides and / or ethane and / or propane used will. 6. The method according to any one of claims 1 to 5, characterized characterized that the extracted Adsorbents can be used again, especially in the Processing of oils and fats and preferably at Processing of paraffinic and glycerid oils and fats. 7. The method according to any one of claims 1 to 6, characterized characterized that from the bleaching earth extracted oil and / or fat, especially after repeated ger refining, is used as edible fat or oil. 8. The method according to any one of claims 1 to 7, characterized characterized that the extracted fats and / or oils from carbonic acid, e.g. B. by relaxation, be separated and the carbonic acid in one preferably  closed cycle for the extraction of bleaching earth is used again. 9. Device for extracting oils or fats from adsorbents, in particular for carrying out the method according to one of claims 1 to 8, with a pressure-resistant extraction container for extracting the oils or fats from the adsorbents by means of a solvent, with a compressor to provide the Desired extraction pressure, with a heating device to provide the desired extraction temperature, and with at least one, optionally several separators for separating the fats or oils from the solvent, characterized in that the extraction agent is supercritical carbonic acid, that the extraction container ( 12 ) with a feed line ( 44 a) and a discharge line ( 44 b) for the supercritical carbonic acid is provided that in the extraction container ( 12 ) there is an insertable or executable batch container ( 30 ) which contains the adsorbents to be extracted, in particular bleaching earth ( 32 ) , and that d he extraction container ( 12 ) is provided with at least one seal ( 40 ) which can be sealed essentially gas- or pressure-tight. 10. The device according to claim 9, characterized in that the batch container ( 30 ) can be flowed through by the supercritical carbonic acid via walls which are at least partially made of sintered metal areas. 11. The device according to claim 9, characterized in that the batch container ( 30 ) has a fit shape, the batch container ( 30 ) with its outer walls in the extraction container ( 12 ) can sit so that it rests essentially sealingly on the inner walls , whereby the supercritical carbonic acid essentially union through the adsorbents to be extracted, in particular bleaching earth ( 32 ). 12. Device according to one of claims 9 to 11, characterized in that additional circumferential seals ( 36 ) on the inner wall of the extraction container ( 12 ) and / or the outer wall of the batch container ( 30 ) are provided. 13. Device according to one of claims 9 to 12, characterized in that at least the outer wall of the batch container ( 30 ) and the Innenwan extension of the extraction container ( 12 ) to each other in the insertion direction of the batch container ( 30 ) tapered. 14. The device according to one of claims 9 to 13, characterized in that the batch container ( 30 ) is predominantly permanently installed in the extraction container ( 12 ) and is provided with means for supplying bleaching earth to extract or extracting bleaching earth and / or the extracts, such as B. oils, abzufüh ren. 15. The device according to one of claims 9 to 14, characterized in that both the batch container ( 30 ) and the extraction container ( 12 ) with means for continuous or semi-continuous supply or for separate removal of the adsorbents, in particular bleaching earth and / or Extracts, e.g. B. fats are equipped, the means z. B. may consist of pressure-resistant locks. 16. The device according to one of claims 9 to 15, characterized in that the extraction container ( 12 ) can be filled directly with bleaching earth to be extracted or emptied from it, the corresponding conveying function, for. B. screw from transport, in particular via pressure-resistant locks, or is exerted by gravity, so that no batch container ( 30 ) is required. 17. The device according to one of claims 9 to 16, there characterized in that the Heizvor direction is integrated in the extraction container. 18. The apparatus according to claim 17, characterized in that the heating device has a line arrangement which is provided in or on the wall of the extraction container ( 12 ), with the line system ( 38 ) liquid is passed at a controllable temperature. 19. Device according to one of claims 9 to 18, characterized in that both the batch container ( 30 ) and the extraction container ( 12 ) is provided with a stirring device which can be set in motion continuously or intermittently during the extraction.