Process of obtaining a fiber fraction useful as dietary supplement from press cake produced from palm oil extraction

Abstract

The present invention refers to a process for obtaining a fiber fraction useful as a dietary supplement for animals generated during the palm oil extraction process, which involves an initial separation of said fraction from a solid material obtained from pressing the fruits obtained from the bunches of the oil palm, and a drying step in which said fraction is obtained with a humidity percentage lower than 15%, to later be used as a dietary supplement for animals.

Description

[0001] FIBER FRACTION SEPARATION PROCESS

[0002] USABLE AS A DIETARY SUPPLEMENT FROM PRESS CAKE GENERATED IN THE EXTRACTION OF PALM OIL

[0003] TECHNICAL BACKGROUND

[0004] The oil palm industry has grown significantly in recent years due to the versatility of all parts of the plant. The trunk, leaves, and fruit of the oil palm can all be utilized. The trunk and leaves are used as raw materials in furniture and paper pulp production, while the fruit is primarily used to obtain palm oil. Currently, oil palm cultivation produces the highest yield per hectare, and this oil is widely used in the food and oleochemical industries.

[0005] Palm oil extraction begins with harvesting the fruit by cutting the bunches that contain it directly from the tree. In these bunches, the fruit makes up approximately 65% ​​of the bunch's weight, while the remaining 35% is the rachis, which is characterized by a high fiber content and is responsible for supporting the fruit on the tree.

[0006] The processing of the bunches for oil extraction requires the implementation of processing plants, in which the processing begins with the sterilization of the bunch at high temperatures, which also seeks to avoid possible increases in free fatty acids, facilitate the mechanical separation of the fruit, and prepare the mesocarp of this for a subsequent pressing stage.

[0007] Following this, the material undergoes a process of detaching the fruits from the rachis so that these fruits can be pressed later; then, this material passes to a digester that macerates and conditions the fruits to be able to extract the oil in the next pressing step.

[0008] The pressing is done in a screw press, which compresses the fruit to extract the oil, in such a way that two streams are obtained: a liquid stream known as press liquor, which enters a clarification stage that seeks to recover and purify the greatest amount of red oil, and a solid stream known as press cake, which contains several by-products that can be used.

[0009] The byproducts of the palm kernel cake include the fruit nuts and fiber, which are subsequently separated using a defibering column. The fiber-free nuts are stored in drying silos and then passed through breaker mills that produce a mixture of hull and kernel. The components of this mixture are then separated to obtain the hull, which is later sold or used as boiler fuel, and the kernel, which is dried, stored, and pressed to obtain palm kernel oil and palm kernel cake. The latter can be used as animal feed.

[0010] On the other hand, the fiber exiting the defibering column passes through a cyclone, which slows the fiber flow rate, and a conveyor that removes some of the moisture. This fiber, comprising between 13% and 17% of the total bunch, contains between 6% and 12% residual oil relative to the dry fiber, 36% moisture, and a calorific value of 2700 kcal / kg. Therefore, the resulting fiber is commonly used in boilers to produce steam for the processes and usable energy for the plant via steam turbines. This allows it to meet the plant's energy demands and, depending on the plant's capacity, could even generate more energy than required.Consequently, there is usually an excess of fiber that is problematic as solid waste, so the need arises to propose alternatives to reduce such solid waste, for example, by using this byproduct in other fields.

[0011] In connection with the above, the state of the art describes different strategies for the use of the by-products obtained, including their use as food for living beings.

[0012] Such is the case of application KR20140060124, which shows the use of a by-product (fruit mesocarp fiber) from the palm oil production process, or hydrolysate thereof, as livestock feed, where hydrolysis processes are used to increase the carbohydrate content in the feed.

[0013] Furthermore, the article “Utilization of African Palm Oil Extraction By-products in Animal Production” describes the use of the solid residue obtained after the pressing process (referred to in the article as cachaza) for feeding programs due to its high fat content with a significant percentage of essential fatty acids. This article reports that cachaza can completely replace the traditional energy source (in this case, soybean meal fortified with vitamins and minerals) for fattening pigs, and also that cachaza can replace 50% of the molasses used in the production of nutritional blocks for cattle, thus proving that the by-products obtained from cachaza are suitable as animal feed.

[0014] Additionally, application N16051704 describes a method for extracting a fraction of the fiber obtained from pressing, which has better characteristics for use as a dietary supplement for ruminants due to its high residual oil content and low fiber percentage. This application describes the initial separation of the pressing fiber from the pressing cake using a defibering column, followed by the separation of two fractions of this pressing fiber using a separating drum. One fraction consists of long, tangled threads that are used as fuel for the boiler, while the other fraction comprises a fine, dense, granular material suitable as a dietary supplement for ruminants.However, the subsequent processing of the pressing cake to obtain this granulated material is costly because it requires a large separator drum for fiber separation, as well as additional screw conveyors and bucket elevators to carry the fiber threads to the boiler, which increase the energy demand of the process, and even an additional purification step of the granulated fiber fraction.

[0015] Therefore, and considering that a usable fraction as a dietary supplement has been identified within the fiber obtained from the pressing process, the need arises to continue developing methodologies that allow the separation of said fraction comprised of the granulated material usable as a dietary supplement for animals, and that methodologies can also be proposed that require a lower amount of energy to carry it out.

[0016] Basic features of the invention

[0017] Now, taking into account the lessons of the prior art and based on the processes currently known in the prior art involving the by-products of the palm oil extraction process, the applicant of the invention in question considered it important to develop a process to obtain in a more efficient and novel way the fraction of fiber usable as a dietary supplement contained in the pressing cake.

[0018] Based on this, the applicant starts with the definition of two fiber fractions, the fibrous yarn fraction and the granulated fraction, to develop a process that allows the separation of the granulated fraction from the rest of the press cake resulting from palm oil extraction, during its transport to the defibering column. This process comprises the following stages: 1. Separation of the granulated fraction from the rest of the press cake (nuts and fibers) by means of a screw conveyor with perforated paddles.

[0019] 2. Drying of the granulated fraction by means of a drying system consisting of a pneumatic conveyor coupled with a radiator, and a cyclone.

[0020] In this line of thought, the granulated fraction is separated from the press cake during its transport from the press, where the granulated part, on one side, goes to a drying system, and on the other side, the nuts together with the fibrous fraction go to the defibering column, and continue the respective separation of the nuts from the rest of the fiber.

[0021] After this separation stage, the granulated fraction is dried, removing the water it contains until it reaches a moisture content of less than 15%. This dried granule will be used as a dietary supplement for animals, such as ruminants, due to its high fat content, as well as its significant protein, fiber, total carbohydrate, and caloric value, making it a valuable feed option.

[0022] Additionally, the process of separating the usable fraction for dietary supplementation, as described in this document, is advantageous because it allows for the processing of this fraction separately from the treatment of the rest of the fiber. In this regard, and considering that most of the fiber present in the press cake consists of fibrous yarns, the number of stages that the bulk of the fiber (fibrous yarns) will have to undergo will be significantly reduced. Furthermore, smaller equipment will be required to process the usable fraction (mainly the granulated fraction), which will directly impact the monetary costs and energy requirements of the process.

[0023] Another advantage of using a perforated paddle conveyor is that it produces a granulated fraction with a low percentage of fibrous impurities. Therefore, it would not be necessary to subject the granulated fraction to a purification step, for example, using a separating drum or a pneumatic defibrating column.

[0024] On the other hand, the fibrous threads used as fuel continue their journey to the boiler without being affected by the stages of obtaining the granulated fraction, so that, in the event of an eventuality during the separation of said fraction, the obtaining of usable fiber as fuel would not be interrupted.

[0025] Detailed description of the invention

[0026] Taking into account the above, the object of this application and the surprising technical advantages achieved by the inventor, the essential, although not limiting, characteristics of the process for separating the fraction usable as a dietary supplement from the pressing fibers generated in the extraction of palm oil developed are described in detail below.

[0027] For a better understanding of the present invention, the process is illustrated in the following figures:

[0028] Figure 1: General scheme of the process of separating the granulated fraction from the pressing cake from the extraction of palm oil as defined by this application.

[0029] Figure 2: Detailed view of the modified screw conveyor with perforated troughs used in the process described in this document.

[0030] Figure 3: Schematic of a preferred embodiment of the process of separating the granulated fraction from the press cake resulting from the extraction of palm oil of the present application.

[0031] Figure 4: General scheme of the separation process of application N16051704 of the granulated fraction of the press cake from the extraction of palm oil. In Figure 1, the process defined in this application begins with the pressing (1) of a previously sterilized material comprising fresh fruit bunches of the oil palm, from which red oil is obtained, which is then processed and clarified to obtain palm oil, and the press cake, which passes to the subsequent separation steps, as described below.

[0032] The pressing cake, containing the nuts and fiber of the treated fruits, passes through a modified cake conveyor with perforated troughs (2) that allow the exit of the granulated fraction with impurities from the fibrous thread fraction (approximately less than 15%) while the rest of the cake, made up of the nuts, the fibrous thread fraction and part of the unrecovered granulated fraction, is taken to the defibering column (5) for separation where, on one side, the nuts continue the respective processing to obtain palm kernel oil and palm kernel cake, and on the other side, the fibrous thread fraction along with part of the unrecovered granulated fraction pass through a cyclone and reach the boiler (6) where they will serve as fuel for the plant.

[0033] In addition to the above, Figure 2 shows in detail the design of the modified press cake conveyor (2), which consists of a screw conveyor equipped with drive paddles and perforated lamellar plates (2a) at the bottom of the conveyor. The perforations in the lamellar plates (detail A) allow the granulated fraction to pass out of the conveyor as the rest of the press cake passes into the defibrating column.

[0034] In some embodiments of the present invention, the modified cake conveyor (2) has a perforated sheet plate (2a) located in a section of its underside. In specific embodiments of the invention, the perforated sheet plate (2a) extends the length of the conveyor (2), covering its entire underside. In other embodiments, the conveyor (2) has more than one perforated sheet plate (2a) located in at least one section of its underside. In some embodiments of the present invention, the perforations in the sheet plates (detail A) located on the underside of the cake conveyor are the same size, ranging from 2 to 6 mm in diameter. In other embodiments of the present invention, the perforations in the cake conveyor can vary in size between 2 and 6 mm in diameter.In specific embodiments of the invention, the conveyor perforations of different sizes are distributed homogeneously along the bottom plate of the conveyor. In other specific embodiments, the size of the perforations decreases along the conveyor, such that in the first section of the conveyor the perforations are 6 mm, and the perforation size is reduced to 2 mm.

[0035] After the pressing cake travels through the modified conveyor (2), the granulated fraction passes, with the help of a screw conveyor, to a drying system (3), responsible for reducing the amount of moisture in the granulated fraction to a percentage of less than 15%.

[0036] In some embodiments, the drying system (3) consists of a pneumatic conveyor (3a), which is connected to a radiator that raises the air temperature to dry the material, a cyclone (3c) that reduces the velocity of the airflow containing the material, and a hopper that collects the treated material. In a preferred embodiment, the pneumatic conveyor (3a) is further coupled to a vertical column (3b) that increases the contact area of ​​the particles with the hot air to achieve faster and more efficient drying of the granulated material.

[0037] In a preferred embodiment, the drying system (3) further comprises a second pneumatic conveyor (3a') and a cyclone (3c') to remove a greater amount of residual moisture from the material. In another preferred embodiment, the second pneumatic conveyor (3a') is further coupled to a second vertical column (3b'). In another embodiment, the granulated fraction subjected to the drying process is collected in an airlock and then fed into a separating drum, which comprises, at its base, sheets with circular perforations or rectangular mesh screens with pores ranging in area from 16 to 36 mm². 2This process allows for the separation of any remaining impurities (mainly fibrous threads) from the granulated material. Separation occurs based on particle size differences, similar to how it happens with sieves, where the granulated fraction passes through the perforations in the plates. The granulated fraction exits through these perforations as the remaining fibrous thread impurities pass along the drum. The fibrous threads are conveyed by a screw conveyor to the fiber fraction separated from the nuts in the defibering column (5), which is then directed to the boilers (6).

[0038] Finally, after a granulated material with a moisture content of less than 15% is obtained, it arrives at a storage hopper (4), where the product will be stored for subsequent packaging and distribution.

[0039] COMPARATIVE EXAMPLES

[0040] Example 1

[0041] In accordance with the achievements described throughout this document, the applicant develops a process for obtaining granulated fraction that includes, but is not limited to, the following stages according to Figure 3:

[0042] 1. Obtaining the pressing cake from fresh, sterilized, defruited and digested fruit bunches.

[0043] 2. Transport of the pressing cake by means of the modified conveyor (2) to obtain the wet granulated fraction.

[0044] 3. Separation of nuts, fibrous threads, and unrecovered granules using a defibering column (5). 4. Passage of the recovered wet granule fraction through a drying system (3), comprising:

[0045] a. the initial passage through a pneumatic conveyor (3a) connected with a radiator and a vertical column, followed by a cyclone (3b), so that the semi-dry product reaches a hopper; and b. the passage through a second pneumatic conveyor (3a') connected with a radiator and a vertical column, followed by a cyclone (3b') and a storage hopper (4), where the dry granulated fraction will arrive.

[0046] Example 2

[0047] In order to more objectively evaluate the advantages of the process described in this document, some comparative data are shown below between the process described by application N16051704 and the process of Example 1, with which the granulated fraction of the fiber from the palm oil extraction process is obtained, which is usable as a dietary supplement for animals.

[0048] Tables 1 and 2, respectively, contain information related to the percentages of components obtained in the most important stages of the processes of application N16051704 (Figure 4) and Example 1 (Figure 3).

[0049] TABLE 1. Percentage weight values ​​of by-products obtained in the essential stages of the process defined in application N16051704.

[0050]

[0051] * The values ​​are calculated with respect to the starting quantity of fresh fruit bunches

[0052] TABLE 2. Percentage values ​​by weight of the by-products obtained in the essential stages of the process defined in this application.

[0053]

[0054] * The values ​​are calculated with respect to the starting quantity of fresh fruit bunches

[0055] Based on the values ​​reported above, Table 3 shows the comparative results of the total weight percentages with respect to the weight of the fresh fruit bunch for the final by-products obtained in the compared processes:

[0056] TABLE 3. Total weight percentage values ​​for by-products obtained in the compared processes

[0057]

[0058] *The values ​​are calculated with respect to the starting quantity of fresh fruit bunches. As can be seen in the tables above, the recovery of the final by-product of interest called “Dry Recovered Granules” is greater with the process of the present invention compared to that of application N16051704. In addition, there are several points in the process defined by this document where moisture losses occur, so the total water loss with the process of the present application is greater than in the process of the reference application.

[0059] Additionally, and considering that the granulated fraction may contain impurities of fibrous threads, as well as residual moisture, the quantities present of each of these components in the final by-product obtained with each of the compared methods were studied, yielding the information reported in Table 4 below:

[0060] TABLE 4. Weight percentage values ​​for the components of the Dry Recovered Granules

[0061]

[0062] ** The values ​​are calculated with respect to the amount of dry recovered granules obtained at the end of each process

[0063] These results show that not only is a higher percentage of granulated fraction obtained with the process of the present invention, but it also has a lower percentage of impurities.

[0064] In this regard, and given that the amount of granulated fraction exiting the modified conveyor contains a reduced quantity of impurities, further purification of this fraction using a separator drum or a defibering column is unnecessary, thus reducing costs by eliminating the need for additional separation stages. Considering that the purity of the recovered dry granules is achieved with a single separation operation (modified conveyor), while the process in the reference application yields a product with lower purity after three separation operations (first defibering column, separator drum, second defibering column), we can conclude that the efficiency of obtaining this material is improved. This is because the number of pieces of equipment required to achieve acceptable purity is lower, and consequently, energy consumption is reduced compared to the process in application N16051704.

[0065] On the other hand, the process of separating the granulated fraction as described in this document allows the granulated fraction to be handled separately from a large part of the fibrous thread fraction, which ensures that the boiler's access to said fibrous threads is constant, even if some kind of eventuality occurs with the separation of the granulated phase.

Claims

CLAIMS 1. A process for obtaining a usable fiber fraction as a dietary supplement from the press cake resulting from the palm oil extraction process, comprising the steps of: a. Separate the usable fiber fraction from the pressing cake using physical means. b. Dry the usable fiber fraction 2. The process of claim 1, wherein the fiber fraction usable as a dietary supplement is a granulated fiber fraction.

3. The process of claim 1 or 2, wherein the separation of the usable fiber fraction occurs by means of a modified screw conveyor (2).

4. The process of claim 3, wherein the modification of the screw conveyor (2) comprises the placement of at least one perforated sheet plate (2a) in at least one section of the lower part of the conveyor.

5. The process of claim 4, wherein a perforated laminar plate (2a) spans the entire length of the endless conveyor (2).

6. The process of any of claims 3 to 5, wherein the holes in the laminar plates comprise sizes between 2 and 6 mm in diameter.

7. The process of any of claims 3 to 6, wherein the size of the holes in the laminar plates (2a) decreases from the inlet to the outlet of the conveyor.

8. The process of any of claims 1 to 7, wherein the drying stage of the usable fiber fraction occurs by means of a pneumatic conveyor (3a) coupled with a radiator and / or a cyclone (3c).

9. The process of any of claims 1 to 8, wherein the drying stage comprises a second pneumatic conveyor (3a') coupled with a radiator and / or a cyclone (3c').

10. The process of any of claims 8 or 9, wherein the pneumatic transport (3a, 3a') is further coupled with a vertical column (3b, 3b').

11. A modified endless conveyor (2) comprising at least one perforated sheet plate (2a) located in at least one section of the bottom of the conveyor.

12. The screw conveyor of claim 1, wherein a perforated sheet plate (2a) spans the entire length of the screw conveyor 13. The endless conveyor of claim 11 or 12, wherein the holes in the laminar plates (2a) comprise sizes between 2 and 6 mm in diameter.

14. The endless conveyor of any of claims 11 to 13, wherein the size of the holes in the laminar plates decreases from the inlet to the outlet of the conveyor.