EP0822893B2 - Worm press - Google Patents

Abstract

PCT No. PCT/AT96/00083 Sec. 371 Date Oct. 27, 1997 Sec. 102(e) Date Oct. 27, 1997 PCT Filed Apr. 26, 1996 PCT Pub. No. WO96/33861 PCT Pub. Date Oct. 31, 1996A device for the production of oils by pressing and extracting a raw material containing oleiferous or extractable substances in the presence of a liquid or supercritical extraction agent. The device includes an inlet for said raw material, a substantially cylindrical pressing body having outlets for oils and being connected to said inlet, and a press screw movably provided in said cylindrical pressing body whereby said raw material is transported from said inlet into said pressing body and therefrom to a discharge outlet while being pressed. In addition, the pressing body is proof-sealed against its surroundings by a jacket and the press screw and/or the pressing body include outlets wherethrough a liquid extraction agent may be introduced into said raw material present in said pressing body. At the outlet of said pressing body, a pipe permitting degassing of the press cake discharged from the press by applying a vacuum, thus removing the solvent from it, may be provided.

Description

The invention relates to a method for obtaining oils by pressing and Extracting an oil-containing or extraghierbare substances containing raw material in the presence of a Extracting agent wherein an oil or extractable substance / extractant mixture is obtained, from which the extractant is removed, whereby the raw material is comminuted and using a Device is pressed, which device a Feed for the raw material, a compact with a movably mounted therein Press screw, means for introducing the extractant into the compact and a Having outlet for the pressed raw material.

For the purposes of the present description and Claims are the terms "oil" and "oily" also "Fat" or "fatty" respectively "extractable substances" include.

From DE-A - 30 16 877 a method for continuous fat separation from organic raw materials known, wherein the raw materials first crushed, possibly dried, then with a fat solvent be mashed and then fed to a screw press.

Also GB-A - 1 340 484 relates to compression in the presence an extractant.

DE-C 665 873 describes a method according to which during extraction, extraction agent is supplied.

According to the method previously known from GB-A-1 340 484 Palm oil can be obtained by pressing the oily fruit is at the input of the press solvent to the Compressing Good is supplied under normal pressure.

These well-known screw presses, with which the oil is recovered, have the disadvantage that the oil yields to leave something to be desired.

From GB-A-0 918 438 a device is known consisting of three mutually perpendicular arranged presses consists. In the first press, which serves as a feed press, the Preßgut introduced and moved horizontally to the second press, in the second press the Pressed transported vertically down, with oil is pressed from the pressed material, and in the third press the pressed material is further pressed, during the pressing a solvent for the oil is injected into the pressed material. The third press is liquid and gas-tight. About the oil yield when using this known device nothing known.

The invention has as its object to provide a method with which the oily raw material in a single operation at 96-98%, based on the Total oil content, can be de-oiled and which leads to the simplification of the prior art known extraction method.

• eine einzige Preßschnecke vorgesehen ist, die sich in einem Preßkörper befindet und den Rohstoff aus der Zuführung in den Preßkörper und von dort unter Verpressen zu einer Austrittsöffnung befördert, und
• der Preßkörper mit einem Mantel druckfest gegen die Umgebung abgedichtet ist,

und wobei gleichzeitig das Extraktionsmittel unter Druck in den Rohstoff eingebracht wird.This object is achieved according to the invention by a process for recovering oils by compressing and extracting an oil-containing or extractable substance-containing raw material in the presence of supercritical carbon dioxide or a supercritical hydrocarbon as extractant, whereby an oil or extractable substances / extractant mixture is obtained, from which the extractant is removed, the raw material is crushed and pressed using a device, which device comprises a feed for the raw material, a compact having a movable therein press roll, means for introducing the extractant into the compact and an outlet for the compressed raw material

• a single press screw is provided, which is located in a compact and conveys the raw material from the feed in the compact and from there under compression to an outlet opening, and
• the compact is pressure-tight with a jacket sealed against the environment,

and wherein at the same time the extractant is introduced under pressure into the raw material.

A preferred embodiment of the method according to the invention is characterized characterized in that the means for introducing the extractant into the compact Openings are provided in the press screw and / or in the compact which a liquid extractant under pressure in the pressed body Raw material can be introduced.

An expedient embodiment of the invention Procedure is that the jacket in its lower Part of a tub for the collection of the pressed body having exiting oil / extractant mixture.

The tub is suitably with an outlet for the Oil / extractant mixture provided, which outlet gas-tight connected to a pressure vessel.

According to the inventive method are as Extractant carbon dioxide in supercritical state or hydrocarbons in supercritical state used.

It has proved to be advantageous to the crushed Raw material before pressing with an oil-dissolving liquid to treat. In this way, the crushed Removed raw material particles surrounding oil layer, causing the Friction between the particles during the pressing increases is and a very good pressure build-up in the compact or a very good sealing of the compact against upstream end is achieved.

• der triglyceridhaltige Rohstoff zerkleinert wird,
• der zerkleinerte Rohstoff in den Preßkörper eingebracht wird,
• Alkohol und Katalysator durch die Öffnungen in der Preßschnecke und/oder im Preßkörper in den Rohstoff unter Bedingungen eingebracht werden, daß das im Rohstoff enthaltene Triglycerid mit dem Alkohol umgeestert wird, wobei der Fettsäureester gebildet wird, welcher den Preßkörper durch die Auslässe verläßt, wonach
• der Fettsäureester in an sich bekannter Weise gereinigt wird.

The device used in the method according to the invention is also well suited to carry out transesterification. For example, triglycerides contained in the oily raw material can be transesterified with an alcohol to produce fatty acid alkyl esters. The device is therefore also used for the production of fatty acid esters by transesterification of a triglyceride contained in the oily raw material with an alcohol in the presence of a catalyst, wherein

• the triglyceride-containing raw material is comminuted,
• the comminuted raw material is introduced into the compact,
• Alcohol and catalyst are introduced through the openings in the press screw and / or in the compact in the raw material under conditions that the triglyceride contained in the raw material is transesterified with the alcohol, wherein the fatty acid ester is formed, which leaves the compact through the outlets, after which
• the fatty acid ester is purified in a conventional manner.

By transesterification, the reaction of triglycerides, i. vegetable and animal fats and oils, with alcohols, such as methanol, ethanol, butanol and isopropanol, in particular Methanol and ethanol, the monoesters of the Fatty acids as well as glycerin arise. fatty acid methyl ester gain more and more importance as diesel substitute fuel.

From AT-B 394 374 a transesterification process is known. According to this method, an excess of the used Alcohol of 1.10 to 1.80 moles per mole esterified with glycerol Fatty acid used. From AT-B 388 743 is a method for producing a fatty acid mixture from waste fats or oil and the use of this mixture as Kraft- or Fuel known.

Also AT-B 397 966 describes the preparation of Fatty acid esters of lower monohydric alcohols by transesterification for example rapeseed oil. According to this method, the Transesterification in the presence of a solid basic catalyst at a catalyst excess of at most 1.6 moles per mole performed as a glyceride bound fatty acid.

From AT-B 397 510 is a two-stage or multi-stage Transesterification known.

As catalysts for the transesterification are usually basic catalysts, e.g. Alkali hydroxides, metal hydrides, Alcoholates, carbonates or acetates, and acid Catalysts, e.g. Mineral acids, used. The am most commonly used catalysts are sodium and Potassium hydroxide and sodium methylate, which dissolved in alcohol For example, be mixed with a vegetable oil. Such a thing Method is known from AT-B 386 222.

The previously known transesterification begins with a two-phase system from triglyceride and alcohol containing the catalyst, but with increasing reaction progress and formation From ester a homogeneous phase is formed, which by education and excretion of glycerol is again biphasic (Crude ester phase and glycerol phase).

The described use of the method used in the process according to the invention Transesterification device is based inter alia on the Recognizing that the transesterification is advantageous in the oil-containing Raw material itself can be made, so it is not it is necessary to first re-esterify the oil from the raw material win and only then umzt. Transesterification and separation of the fatty acid alkyl ester can thus in a single Step be made.

It is clear to the expert that in this Use of the pressing device initially a two-phase Mixture is obtained, which consists essentially of ester and Glycerol consists, and that the extraction of pure ester from This biphasic mixture with known techniques possible is.

In a preferred use of the press is at the beginning of pressing a Agent introduced into the oily substance, which the Residual moisture of the oil or fat-containing substance binds and thus increased soap formation after addition of the catalyst in derogation.

The pressing is expediently under cooling performed.

With reference to the accompanying drawings, the invention is still explained in more detail.

FIG. 1 shows the section through a screw press of the Prior art, and Figures 2 and 3 show advantageous embodiments of the method used in the method according to the invention Screw press. In the figure 4, the pressure curve in the process according to the invention used screw press along the compact shown.

FIG. 1 shows schematically the section through a previously known screw press (manufacturer: Krupp). The Reference numeral 1 denotes a cylindrical compact, the with a feeder 2 for the to be pressed and Extracting raw material 3 is related. The raw material 3 is detected by the worm threads 11 and in the pressed cylindrical body 1, promoted by this wherein oil is squeezed out of the raw material by Openings usually made by crowbars (not shown) are formed, flows down and the compact 1 leaves. The oil leaving the compact is by means of drops 4 indicated. The oil is taken from a tub (not shown) collected.

The compressed raw material is transported to the transport Pressed body 1 through the outlet opening 6, located in a Component 1a is located on the cylindrical compact body. 1 connects, extruded.

The pressure screw 5 has three in the embodiment shown frusto-conical extensions 12 on which the Pressed material is exposed to increased pressure. After overcoming Such an extension naturally reduces the pressure again something off. Such a pressure change favors the Compression, and at this point injected solvent diffused by the brief relaxation up to Cell wall level.

FIG. 2 shows a section through an embodiment of a used in the inventive method screw press, in a simple manner by conversion of the known, shown in Figure 1 Screw press can be obtained. The shown Screw press has additionally one Jacket 7, 7a, of the compact 1 in the region of those openings (not shown), from which oil 4 in the tub 7a, in the present case with the lower part of the shell 7 identical is, passes, pressure-tight against the environment seals.

The pressure screw 5 is hollow and has openings 8, through which a liquid extractant under pressure in the Preßkörper 5 located raw material can be introduced. The extractant is pressurized via the supply line 13 the hollow press screw 5 is supplied. It has been shown that the pressing of the raw material made in this way simultaneous delivery of extractant under pressure too a very high oil yield of at least 96%, based on the total oil content leads. Due to the high pressures in the pressed material The injected solvent is supercritical Condition and increases the solubility of the oil or the extractable substances in the solvent.

The reference numeral 4a is the from the compact 1 in Range of colanders (not shown) exiting mixture indicated from oil and extractant, which in the tub 7a, which in the embodiment shown from the lower part of Mantels 7 is collected and trapped by the outlet 10 gas-tight in a container (not shown) passes. The oil or the extractable substance can in a known manner by Extraction of the extractant from the mixture oil or Extractable substance / extractant can be obtained.

When using a liquid under normal conditions present hydrocarbon as an extractant this can be separated by distillation.

When using a gaseous under normal conditions hydrocarbon or CO ₂ as extractant this is transferred under pressure and thus in liquid or supercritical state from the press in a pressure vessel and can there by lowering the pressure from the liquid by evaporation or suction and subsequent pressure and temperature drops be fed again in liquid or supercritical state of the press (recovery and recirculation).

It has also been shown that liquid carbon dioxide in the used in the inventive method very good as an extractant can be used. It is clear to the person skilled in the art that in this case worked under pressure / temperature conditions under which carbon dioxide in liquid form or supercritical form is present. This applies both in the Feed line 13 and in the hollow press screw 5, as well during the compression of the raw material, ie within the Preßkörpers 1, in the tub 7 a, in the outlet 10 and in the subsequent collecting container, which in this case as Pressure vessel must be executed. By pretending such Pressure and temperature conditions is in the tub 7a and in subsequent pressure vessel a liquid mixture of oil or extractables and carbon dioxide. The carbon dioxide can by means of evaporation by a simple pressure reduction removed from the mixture.

FIG. 3 shows another preferred embodiment of the invention in the inventive method used in which the Extraction agent, ie liquid hydrocarbon or liquid carbon dioxide, not via the pressure screw 5, but on the compact 1 in the raw material currently being processed is introduced. These openings are denoted by the reference numeral 9 designated. The extractant is by means of the supply lines 14 the openings 9 fed.

Advantageously, the openings 9 are each directly provided for an extension 12 of the pressure screw 5. This improves the oil production in particular.

Shortly before the discharge of the material to be pressed from the press, a Flushing nozzle (not shown) may be provided by which acids and / or oil displacing and / or oil-soluble substances can be injected additionally.

FIG. 4 shows the pressure course within the pressed body 1, wherein the X-axis is the length of the cylindrical compact and the ordinate indicates the pressure. It is the figure 4 too can be seen that the pressure increases as soon as the screw 5 the Pressed material detected and transported in the compact 1. For one good pressure build-up, it is important that the crushed Raw material by washing with extractant superficially the oil layer is freed. In the figure 4 are exemplary Pressed.

The pressure initially rises continuously in the compact 1, until the first extension 12 is overcome, reducing the pressure drops sharply and then until the next expansion 12 continuously increasing again. This pressure change will the oil production improves or will be the re-orientated pressed particles.

In the following, a preferred embodiment of inventive method for the production of oil concrete described.

The raw materials are processed before processing of non-oil Dietary fiber is released and released. Then they will dried to a water content of about 2-5%.

After drying, the oily raw materials to a Grit size of 0.5-2 mm crushed. Then they will with an oil-dissolving liquid, e.g. Hexane, and / or one Acid washed. The prepared, moist raw material can be fed to the press.

By the complete separation of the shells from the raw material can the pressing capacity compared to the known methods increased by up to 40%. By this separation is Further, the protein content of the press cake to the falling away Shell part increased.

At the exit of the press cake from the press is the Extractant content between 4-8%. This is essential less than in the methods known today.

The device used in the method according to the invention allows at the exit 6, the exiting pressed material in a hot state in a pipe lead (not shown), which provided with suction openings is to the emerging after the pressure release Recover solvent via suction and condensation. This will save energy for the removal of Residual solvent significantly reduced because the Preßgutwärme to Evaporation of the solvent is exploited.

As already mentioned above, can be used in the process according to the invention Device can also be used in triglycerides Catalyzing raw material during compression. To instead of the extractant is a mixture of alcohol and Catalyst through the openings 8 and 9 in the raw material brought in. The pressing body 1 leaving the liquid 4th or 4a is in this case a mixture of ester, glycerol, Alcohol and catalyst from which the ester on known Way can be won.

When transesterification, the shredded raw material should no longer contain 0.5% water. Appropriately, the is to Processing raw material already before the Verpessung with Alcohol / catalyst mixture in contact for about 20-30 minutes brought.

The use of the described Pressing screw allows transesterification of more than 99% to reach.

Claims (5)

1. A process for the production of oils by pressing and extracting a raw material containing oleiferous or extractable substances in the presence of supercritical carbon dioxide or a supercritical hydrocarbon as an extraction agent, wherein an oil or extractable substances/extraction agent mixture is obtained from which the extraction agent is removed,
   characterised in that
   said raw material is comminuted and pressed using a device, said device having an inlet (2) for the raw material, a pressing body (1) with a movable press screw (5) being movably mounted therein, means (8; 9) for introducing the extraction agent into the pressing body (1) and a discharge outlet (6) for the raw material pressed, wherein

   one single press screw (5) is provided which is arranged in a pressing body (1) and transports the raw material (3) out of the inlet (2) into the pressing body (1) and from there to a discharge outlet (6) while pressing is effected, and

   the pressing body (1) is sealed in pressure-tight manner relative to the environment by means of a jacket (7) and

   wherein said extraction agent is simultaneously introduced under pressure into the raw material.
2. A process according to claim 1, characterised in that said means (8; 9) for introducing the extraction agent into the pressing body (1) are outlets provided in the press screw (5) and/ or in the pressing body (1), through which a liquid extraction agent may be introduced under pressure into the raw material present in the pressing body (1).
3. A process according to one of claims 1 or 2, characterised in that the jacket (7) comprises a tub (7a) for collecting the oil/extraction agent mixture emerging from the pressing body (1).
4. A method according to one of the claims 1 to 3, characterised in that the tub (7a) is provided with an outlet (10) for the oil/extraction agent mixture, said outlet being connected in a gas-tight and pressure-tight manner to a pressure container.
5. A process according to one of the claims 1 to 4, characterised in that the comminuted raw material is treated with an oil-dissolving liquid prior to pressing.

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