WO2006088433A2

WO2006088433A2 - Method for extracting fibres from oil palm parts and making biodegradable pallets therefrom

Info

Publication number: WO2006088433A2
Application number: PCT/SG2006/000031
Authority: WO
Inventors: Yew Pong Tay
Original assignee: He, Minrong
Priority date: 2005-02-16
Filing date: 2006-02-16
Publication date: 2006-08-24
Also published as: WO2006088433A3

Abstract

A process for extracting fibres form oil palm parts, including empty fruit bunches (EFB) for use in making hard board-like articles, such as a pallet, is disclosed. The process comprises the steps of feeding the EFB to a cutter, cutting the EFB into small/fine pieces, defibrating the cut EFB pieces into strands of fibres, and washing to remove oil from the fibres. The EFB fibres are admixed with adhesive composition which may include latex, plant-based starch composition and an alkaline compound as preservative such as sodium hydroxide (NaOH). Multiple layers of the adhesive admixed fibres are spread evenly over a plane and compressed into a pre-moulding piece (52) for ease of handling. The pre-moulding piece is then over-dried until 20 % moisture remains before it is placed in a pallet mould and compressed to form the completed pallet (54) which is left to set, dry and/or cure in ambience.

Description

Method for extracting fibres from oil palm parts and making biodegradable pallets therefrom.

TECHNICAL FIELD

This invention relates a method of extracting fibres from oil palm parts, including empty fruit bunches (EPB) .

The extracted fibres may be used to make fibreboard articles, including hardboard, pallets and the like which are biodegradable .

BACKGROUND ART

In the process of extracting palm oil from the fresh fruit bunches (FFB) of the oil palm, the palm oil industry generates a huge amount of leftover plant materials such as the empty fruit bunches (EFB) , which are FFB that have been stripped of fruits, as well as mesocarp fibres and kernel cake, among others, in the process of milling for palm oil.

These leftover palm materials are discarded by the palm oil mills as fibre-rich waste materials.

EFB tops the other oil palm parts in volume terms and has become a big disposal problem for the palm oil mills despite EFB' s relatively long natural fibres in the bunch stems that remained undamaged from the steaming and mechanical threshing (which may include tearing, crushing, pressing and/or raking) to separate the steam-loosened fruits from the bunch. The mounds of EFB that are not burned (due to environmental concerns) may still be a fire or smoking hazard if left long enough for thermophilic fungi and bacteria to decompose the ligno-cellulosic materials comprising the EPB fibres.

Attempts in recycle or reprocess EPB for various uses, whether reprocess to recover its fibres for various uses, or use of EFB in whole as compost, fuel, building materials, etc. have seen a limited or relatively meagre consumption of the ever increasing EFB stockpile discarded by the palm oil industry. Some of the earlier patents that we are aware of concerning the use of oil palm parts are each discussed briefly in the following.

U.S. Patent No. 6,758,892 (Universiti Putra Malaysia) discloses reprocessing of cellulose fibres from oil palm to specific micron sizes which are then pelletized with light asphalt emulsions with emphasis on the flowability of the composition for use as paving material. The fibre length of EFB is not taken advantage of as would be required for the purpose of strength in the case of making fibre board.

U.S. Patent No. 6,197,414 (Matsushita Electric) discloses a process for recovering lingo-cellulose long fibres from oil palm, particularly empty fruit bunches (EFB) which includes claiming various methods for orientating the fibres in many configurations including mutual perpendicular direction, twined, multiple layers, unidirectional, bidirectional, etc. and treatment such as hot-pressing the fibres, etc. Fibre board composition of high mechanical strength is claimed to be made therefrom. Our experience indicates that processing the EFB fibres in specific orientation is impractical as well as having inconsistent result .

U.K. published patent application No. GB 2,162,554 (Yoshio Miyata) discloses a process of recovering oil palm fibres, particularly from a fruit bunch. It teaches a process of cutting the empty fruit bunch (EFB) into small pieces and breaking up the small pieces to give out a dry loose mass of fibrous material and separating the fibres. Except for convention machines, there is no mechanical means

(specific machine or apparatus configuration) disclosed to enable this process. The fibres are dipped in latex mixture and cured to produce rubberised fibres which are used to form car seats, cushions, mattresses, carpet underlays and filters. There is no suggestion of making fibre boards, especially hard boards.

Japanese Patent No. JP-9-117, 906 (Toa Shoj i K. K.) discloses the use of empty fruit bunch (EFB) of oil palm to obtain plant fibres to make moulded fibre boards. The fibres are obtained from splitting of EFB and is added with adhesive under specific heat and pressure moulding process so that the entwinement of the fibres and sectional diameters of the air- permeable spaces between the fibres are maintained while resulting in a product that has water-proofing properties. A number of different configurations of EFB admixed with jute fibres and/or wooden chips to produce fibre boards are disclosed. The fibre moulding product may have different corrugations, layers or laminations, thermal protection and even appear to be able to be used with pre-cast concrete shuttering to form building parts.

An object of our method for extracting fibres from oil palm parts is to enable a rapid extraction of fibres from EFB without being hindered by laying out the fibres in specific orientation or entwinement. Another object of our invention is to process the extracted fibre by admixing with a totally plant-based adhesive so that the resultant fibre board article moulded therefrom is totally biodegradable. Yet another object is to provide a composition of EFB fibres admixed with the plant-based adhesive so that the composition has rheological properties suitable for layering and compression moulding to form with ease articles of use that is biodegradable and yet has the strength and sturdiness of conventional fibre hardboards .

SUMMARY OF DISCLOSURE

The general embodiment of our invention provides for a method for extracting fibres from oil palm parts comprising the steps of (i) feeding said palm parts to a cutter; (ii) cutting said palm parts into small/fine pieces; (iii) defibrating palm part from the preceding step into strands of fibres; and (iv) washing to substantially remove oil from resultant palm fibres, not necessarily in the same order.

In this specification, "defibrating" is taken to mean the process of separating or loosening a fibrous material into strands of fibre or fibrous constituents, as employed in US-6, 197,414 (Matsushita Electric).

Specific embodiment of each step may be provided, for instance, the cutting is performed with a rotary barrel cutter and/or the defibrating is performed with a hammer mill. Preferably, the fibres obtained is dried and compacted. The oil palm part used in our process preferably is empty fruit bunches (EFB) .

In one aspect of the invention, the palm fibres are further admixed with adhesive composition which may include agents for controlling the rheological properties of the fibre admixture. The agents preferably include any one or a combination of gelling, emulsifying, thickening, pigments, and preservative agents. In a specific embodiment, the adhesive composition includes latex compositions which do not vulcanise. Preferably, the adhesive composition includes plant -based starch compositions and optionally includes an alkaline compound as preservative which may be sodium hydroxide (NaOH) .

In another aspect of the invention, the density of the fibre admixture may be controlled according to the type of product to be made, i.e. which may vary from low density foam-like impact-absorbing material to high density hard board-like material.

The fibre admixture may be spread over a plane as a layer with latex simultaneously added thereto. Optionally, multiple layers may be thus laid with latex simultaneously added to each layer. The multiple layers may undergo a first compression to obtain pre-moulding product piece which has sufficient integrity, density or hardness for ease of conveying, transport and the like in subsequent manufacturing process. The pre-moulding product piece may further undergo oven-drying to reduce moisture content to about 20% of weight .

In one specific embodiment of the invention, the product is a pallet. Specifically, the oven-dried pre-moulding product piece may therefore be laid in a mould-half of a pallet and is compressed into pallet form with the other mould-half. Thereafter, the moulded pallet is removed from the mould halves and allowed to set, dry and/or cure in ambience . LIST OF ACCOMPANYING DRAWINGS

The present invention will be better understood with reference to the accompanying drawings and the detailed description that follows hereinafter wherein specific embodiments are described as non-limiting examples or illustrations, in which:

FIGURE 1 shows a flowchart of the process of the invention from the empty fruit bunches to obtaining fibres therefrom, to moulding a pallet from the fibres ; FIGURE 2 shows a first embodiment of a pallet obtained with the process of the present invention,- FIGURE 3 shows a second embodiment of a pallet obtained with the process of the present invention; FIGURE 4 shows a third embodiment of a pallet obtained with the process of the present invention; and

FIGURE 5 shows a fourth embodiment of a pallet obtained with the process of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Our invention will now be illustrated with detailed description of the method in obtaining fibres from empty fruit bunches and making pallets therefrom. Our method for extracting fibres may use any parts from the oil palm tree but is preferable that empty fruit bunches (EFB) are used due to the abundance of EFB as discarded material by palm oil mills. Briefly, our method comprises the steps of feeding the palm parts to a cutter, cutting the palm parts into small or fine pieces, defibrating the cut small pieces into fibres, and washing the fibres to substantially remove oil from the resultant fibres which, in the following embodiment, exemplified the processing of fibres from EFB.

FIGURE 1 shows a flowchart of the process of the present invention from the empty fruit bunches to obtaining fibres therefrom, to moulding a typical product using the fibres so obtained, e.g. a pallet. Empty fruit bunches (EFB) collected from the palm oil mills may be dumped into a box feeder (10) which is the starting point of the apparatus for carrying out the process according to our invention.

The EFB are then moved up a loop-beIt conveyor which inclination is relatively steep. Spikes (12) on the belt assist in picking up individual bunch from the heap of EFB in the box feeder. Each EFB so picked up is then allowed to fall over the conveyor's top down to a filter screen (14) from a relatively high position. This enable non-organic materials such as stones and sands to fall through the filter

(14) instead of joining the EFB to be fed into a cutter (16) .

While many conventional cutter may perhaps be used, we have improvised a rotary barrel cutter (16) having a hexagonal cylindrical shape or barrel having six forward facing blades attached thereto which we found to be better in cutting in a shaving effect. The barrel may be configured to rotate at very high speeds to have each of the six forward facing blades to cut the EFB being gradually fed into the cutter (16) so that they may be cut into small pieces.

These small cut pieces of EFB are conveyed via a conveyor belt (18) to a hammer mill (20) where the EFB pieces are defibrated (i.e. have the fibres separated or frayed from each small piece with the hammering action or impact of the hammer into strands) . A conventional rotary hammer mill (20) may be employed for this purpose. The separated strands of fibre successfully defibrated are then picked up by the suction effect of an air pump (22) and air conveyed via a closed conduit as air conveyor, such as a pipe means (24) , to a first tank (30) containing detergent to wash away the oil residue in the EFB fibres. The EFB fibres that settle down at the funnel end of the first tank (30) are those that have been substantially washed of oil residue and are conveyed to the next or second tank (32) .

In the second tank (32) , the fibres are rinsed of the detergent from the first tank (30) and are next moved to the next, i.e. third tank (34) via a screw conveyor (36) . In the third tank (34) adhesive compositions may be added to the fibres to be admixed therewith. It should be noted that our process may terminate at the washing and rinsing steps so that the washed and rinsed fibres may be sold in bulk to manufacturers of loose packing material, cushion and mattress filler materials, composts, and the like. The washed and rinsed fibres may preferably be dried and compacted first before being sold or delivered in bulk to such buyers.

The adhesive composition that is added to the third tank

(34) may include agents for controlling the rheological properties of the fibre admixture so as to arrive at a mixture of fibre gel or paste with a specific flowable properties for ease of application later in the process. Preferably, the agents include any one or a combination of gelling, emulsifying, thickening, pigments, and preservative agents. The third tank (34) may be provided with a stirrer

(35) at the funnel bottom of the tank.

The adhesive composition may preferably contain latex compositions which may or may not be admixed together with the fibres in the same third tank (34) . Regardless of at which point the latex is added, it is important that the latex must not have any vulcanising agents so that no substantial amount of vulcanisation occurs at any point of the process such that the latex is used only as a glue or gelling agent.

Preferably, the adhesive composition includes a plant- based starch composition such as starches made from tapioca, corn, wheat flour and the like, which are totally biodegradable. We are aware that such sources of adhesive may attract decomposing microbes or saprobes too early in the shelf or useable life of our palm fibre product, hence we have added preservatives to the adhesive mixture. Such preservatives must of course conform to the total biodegradability requirement. We have considered using common compounds that may render the- fibre admixture highly acidic or basic to discourage microbe degradation thereon. Specifically, we favour basic or alkaline compounds and have found that sodium hydroxide (NaOH) or potassium hydroxide (KOH) as meeting this criterion besides being cost-effective, biodegradable and environmentally safe.

The adhesive admixed fibre composition in the third tank (34) may be mixed constantly and evenly by a stirrer (35) provided at the funnel bottom of the tank before it is delivered from the tank via a second screw conveyor (38) to a hopper (40) . The hopper has a spreader pipe (42) which allows the fibre admixture to flow out and spread thin along a predetermined plane (48) or area. To assist in the spreading, the pipe (42) may be integrally provided with spreader spokes (44) and rotated to spread the fibre admixture . Instead of admixing latex into the third tank

(34) , it may be added to the fibre admixture at this spreading step as shown in this Figure. A pair of latex- supplying tubes (46a, 46b) may be provided on both sides of the spreader tube (42) so as to simultaneously lay out the latex along with the fibre admixture being laid by the spreader pipe (44) .

The hopper (40) may be mounted on rails enabling it to move to-and-fro between positions 41a and 41b and that the same motion may be transmitted to rotate the spreader pipe (42) and spreader spokes (44) in alternating directions between positions 41a and 41b. The speed of travel of the hopper (40) , distance travelled by the hopper (40) between positions 41a and 41b and speed of the spreader tube's (42) rotation and respective flow speeds of the fibre admixture and latex may be controlled by, for example, a logic controller which may be housed in a control unit accessible by an operator.

It should be mentioned that, apart from the fibre admixture density as mixed in the third tank (34) , the speed of laying the fibre admixture on plane (48) determines the density and thickness of the layer (50) of fibre admixture laid. Accordingly, with a logic controller, the density of the resultant fibre admixture laid may be controlled according to the type of product to be made, i.e. variable, ranging from low density foam-like impact absorbing material to high density hard board-like material. The laying of layers of the fibre admixture (50) may be repeated so that multiple layers are laid with latex being simultaneously added onto each layer.

The multiple layers (50) may be too soft to be handled or conveyed for next treatment or step of the process; hence, it is preferable that the multiple layers of fibre admixture undergo a first compression by hydraulic compressor (51) to obtain a pre-moulding product piece (52) which has certain integrity and hardness for ease of conveying, transport, etc.

The pre-moulding product piece (52) may then be conveyed into an oven (53) for drying to reduce its moisture content to about 20% of its weight so that it is still mouldable. The dried pre-moulding product piece is placed in a mould- half (55) cavity of a pallet (or any other product's mould) and is then compressed into the shape of a pallet with the other mould half (56) acting thereupon by hydraulic means. The formed pallet (54) is then removed from the mould halves and allowed to set to dry and/or cure in ambience. Depending on the composition of the adhesive, fibre density, amount of latex added, and the pre-moulding oven-drying, it may take up to 1 week for the moulded pallet to cure and hardened.

Examples of configurations of the pallet that may be made with the process of this invention are shown in FIGURES 2 to 5. Various configurations of the pallet may be provided depending on load to support, ease of stacking for transport or mass storage when not in use, whether the pallet is an integral piece, or a knockdown version (e.g. where its legs are moulded as separate pieces to be inserted or snapped onto the bottom of the pallet base so that the base may be stacked up more compactly, etc.

FIGURE 2 shows a first embodiment, of a pallet wherein the base (60) is provided with longitudinally parallel ribs (62) to increase the tensile and flexural strength of the base (60) . The legs (64, 65) are provided integrally with and protruding from the bottom of the base (60) to support the base so that there is gap between the ground and the base for a lifting machine, such as the arms of a forklift, to facilitate insertion of its arms to lift the base with load.

The legs may be in the form of a single block (65) or an elongated block (64) attachable across or in transverse of the ribs' (62) orientation for added tensile and flexural strength.

In FIGURE 3, a second embodiment of a pallet is shown wherein the base (60) is moulded separately from the legs (65) which are separate blocks attached to the bottom of the pallet base (60) in tongue-in-groove connection means (66) .

FIGURE 4 shows a third embodiment of a pallet wherein the legs (67) are separately moulded from the base. The legs (67) are moulded as transverse elongated blocks with a top peripheral flange to complementarily support the base so that there appears to be two layers of base at the location where the elongated legs (67) are attached to the base.

FIGURE 5 shows a fourth embodiment of a pallet wherein the elongated legs (64) are moulded integral with the base

(60) . The top portion of the base (60) at where the legs

(64) are provided is shown to have a corresponding complementary depression (64a) so that successive layers of the pallet may be stacked atop one another with the upper pallet's legs resting in the corresponding depression on the lower pallet.

It will be appreciated that a number of the above- described features may be adopted modularly, modified, reconfigured, or alternatively adapted according to the required finishing desired or product type and their corresponding configuration based on the same general concept, features and working principles of the present invention. These variations and alternative embodiments may be used in substitution of the aforesaid parts, components, materials, steps or processes as alternative configurations or embodiments not specifically described herein but which may still be used to effectively work the concept and working principles of this invention. Accordingly, they are not to be considered as departures from the present invention but shall be considered as falling within the letter and scope of the following claims.

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Claims

CLAIMSWhat is claimed is:

1. A method for extracting fibres from oil palm parts comprising the steps of: feeding said palm parts to a cutter; cutting said palm parts into small/fine pieces; - defibrating palm part from the preceding step into strands of fibres; washing to substantially remove oil from resultant palm fibres .

2. A method according to Claim 1 wherein the steps are in the order recited.

3. A method according to Claim 1 wherein the cutting is performed with a rotary barrel cutter.

4. A method according to Claim 1 wherein the defibrating is performed with a hammer mill.

5. A method according to Claim 1 wherein the fibres obtained is dried and compacted.

6. A method according to Claim 1 wherein the oil palm part is empty fruit bunches (EFB) .

7. A method according to Claim 1 wherein the palm fibres are further admixed with adhesive composition.

8. A method according to Claim 7 wherein the adhesive composition includes agents for controlling the rheological properties of the fibre admixture.

9. A method according to Claim 8 wherein the agents include any one or a combination of gelling, emulsifying, thickening, pigments, and preservative agents.

10. A method according to Claim 7 wherein the adhesive composition includes latex compositions which do not vulcanise .

11. • A method according to Claim 7 wherein the adhesive composition includes plant-based starch compositions.

12. A method according to Claim 7 wherein the adhesive compositions includes an alkaline compound as preservative.

13. A method according to Claim 12 wherein the alkaline compound is sodium hydroxide (NaOH) .

14. A method according to Claim 8 wherein the density of the fibre admixture is controllable according to the type of product to be made, variable from low density foam-like impact-absorbing material to high density hard board-like material .

15. A method according to Claim 14 wherein the product is a pallet.

16. A method according to Claim 14 wherein the fibre admixture is spread over a plane as a layer with latex simultaneously added thereto.

17. A method according to Claim 16 wherein multiple layers are thus laid with latex simultaneously added to each layer.

18. A method according to Claim 17 wherein the multiple layers undergo a first compression to obtain pre-moulding product piece which has sufficient integrity, density or hardness for ease of conveying, transport and the like in subsequent manufacturing process.

19. A method according to Claim 18 wherein the pre-moulding product piece is oven-dried to reduce moisture content to about 20% of weight.

20. A method according to Claim 19 wherein the oven-dried pre-moulding product piece is laid in a mould-half of a pallet and is compressed into pallet form with the other mould-half .

21. A method according to Claim 20 wherein the moulded pallet is removed from the mould halves and allowed to set, dry and/or cure in ambience.

22. A pallet obtained from a method according to any one of the preceding claims .

23. An apparatus for carrying out a method according to any one of Claims 1 to 21.

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