Method of manufacturing palm sequestered carbon boards

Abstract

Disclosed herein is the manufacturing of Palm Sequestered Carbon Boards (PSC Boards) from waste date palm leaves. The process includes cleaning palm fronds, baling palm fronds, followed by chipping them to obtain both leaves and midribs. The chipped material is sifted to separate the leaves from the midribs, with the heavier midribs then passed through a roller-type screen to remove fines and oversized material. The acceptable midrib chips are washed and sent to a flaker to produce wet flakes. The lighter material is further separated through a mechanical separator in order to ensure that only the thin leaves go into the board. Both the leaves and flaked midribs are dried and then passed through a specially designed roller-type screen to segregate larger flakes from smaller ones and also to separate dust. These segregated flakes are then treated with resin to form resonated flakes, which are subsequently processed by forming heads to create layers of palm strands, resulting in high-quality, sustainable PSC boards. PSC boards reduce pollution from burning or burying fronds. Utilizing both leaflets and midribs enhances board strength and sequesters carbon, supporting construction decarbonization.

Description

METHOD OF MANUFACTURING PALM SEQUESTERED CARBON BOARDSFIELD OF INVENTION[1] The invention pertains to the field of material science and construction, specifically focusing on the development and manufacturing of palm sequestered carbon (PSC) boards.BACKGROUND OF THE INVENTION[2] PSC boards are widely used in various applications, including cabinetry, flooring, residential construction, Oriented Strand Lumber, wooden I-beams, packaging, wall and floor sheathing, Prefabricated Prefinished Volumetric Construction structures, prefinished buildings, structural insulated panels, formwork, and signage. PSC boards are typically made from palm fronds sourced from sago palms, coconut palms, dwarf palms, fan palms, feather palms, and similar varieties. These fronds have a midrib and supporting small leaflets, often with thorns on the lower midrib portion.[3] A significant issue with palm fronds, especially those from date palms, is that they are often regarded as agricultural waste once trimmed from the trees. Traditional utilization methods mainly process the midribs to create wood chips or other products,frequently discarding the leaflets. This results in underutilization of the raw material and generates waste. Furthermore, the mountains of palm fronds pose a substantial nuisance for municipalities. They take decades to decompose, occupy large areas of valuable land, and provide nesting areas for snakes and pests. Often, they are regularly burned, releasing carbon dioxide (CO2) into the atmosphere and contributing to environmental pollution.[4] Existing technology struggles to effectively use the entire palm frond, including both midribs and leaflets, to produce a commercially viable and sustainable product. Processing whole fronds poses challenges, such as water absorption by the leaflets, leading to operational inefficiencies and reduced product quality during manufacturing.[5] Previous efforts to address these problems have focused on optimizing midrib processing to enhance binder absorption and improve overall product quality. However, these efforts often overlook the integration of leaflets into the manufacturing process and fail to address the comprehensive utilization of palm fronds as a sustainable resource for board production.[6] DE102011118009 Al discloses a method for producing chips from palm fronds, particularly date-oil palm fronds, by separating the leaflets and thorns. The midribs are processed into elongated wood chips, which are then cut into flakes of varying sizes. These flakes are dried and categorized into rough and smooth types, which are subsequently glued together. The process concludes with pressing the surfaces of a board with phenol- impregnated paper. However, this method does notaddress the challenge of effectively utilizing both midribs and leaflets from palm fronds in a single integrated process to maximize material efficiency and produce high-quality PSC boards.[7] Therefore, there is a need for an improved method that maximizes the use of both midribs and leaflets from palm fronds to produce high-quality PSC boards. This method should address water absorption challenges, improve binder absorption efficiency, and optimize the sustainability of board production from agricultural waste materials.OBJECTIVES OF THE INVENTION[8] The primary objective of the present invention is to overcome the issues found in the state of the art by efficiently utilizing entire date palm fronds, including midribs and leaflets, to produce high-quality PSC boards.[9] One objective of the present invention is to optimize water management during processing, ensuring controlled absorption by midribs for improved flaking and preventing water-related issues with leaflets that could affect board production.

[0010] Another objective of the present invention is to develop a robust industrial process that integrates comprehensive separation, washing, and drying systems for midribs and leaflets, thereby streamlining board manufacturing while minimizing waste.

[0011] Additionally, the present invention aims to enhance the mechanical properties of PSC boards by strategically incorporating both midribs and leaflets, thereby producing boards that meet or exceed industry standards for strength and durability.

[0012] A further objective of the present invention is to manufacture and bond the boards using polymeric diphenylmethane diisocyanate (pMDI), which has the lowest emission of formaldehyde, resulting in a No Added Formaldehyde (NAF) rating.

[0013] Another objective is to primarily utilize dead fronds, which would otherwise remain unused and take a considerable amount of time to decompose if buried, thereby taking up large spaces and releasing methane into the atmosphere, or are burned and therefore release CO2 into the atmosphere.SUMMARY OF THE INVENTION

[0014] The present invention relates to a method for producing PSC boards from waste date palm leaves, utilizing both midribs and leaflets, ensuring comprehensive utilization of the date palm leaves and thereby producing high-strength OSB grade 4 boards without causing any wastage. The process achieves a No Added Formaldehyde (NAF) rating by eliminating the use of formaldehyde glue.

[0015] In an embodiment, a method of manufacturing PSC boards out of waste date palm leaves includes baling palm fronds into bales, chipping baled fronds to obtain chipped leaves and midribs, sifting chipped leaves and midribs to separate the leavesfrom the midribs, collecting heavier midribs and passing them through a roller-type screen to remove fines or oversized material, washing the chipped midribs of acceptable size to produce wet midrib flakes, drying the leaves and flaked midribs by passing them through a dryer, passing the dried leaves and flakes through a roller-type screen to segregate larger flakes from smaller flakes, resonating the segregated flakes with resin to form bunkers, and forming sheets of palm strands by passing the bunkers through forming heads.

[0016] In an embodiment, said resin is pMDI, and optionally urea-formaldehyde (UF), melamine-urea-formaldehyde (MUF), or organic-based resins.

[0017] In an embodiment, the sheets are cut to size and compressed to form PSC boards using a plurality of such sheets.

[0018] In an embodiment, each of the PSC boards is cooled following cutting.

[0019] In an embodiment, the removal step comprises removing the remaining dust and sand from the leaves through a bath of water.

[0020] The technical effect achieved by the present invention is repurposing the palm fronds for making PSC boards, avoiding pollution from burning or burial of the palm fronds. The utilization of palm fronds comprising leaflets and midribs enhances the strength of the board and it also sequesters carbon to support construction decarbonization.

[0021] The technical effect achieved by the present invention is various objects, features, aspects, and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like components.BRIEF DESCRIPTION OF DRAWINGS

[0022] Sole Figure illustrates a method for preparing PSC boards out of waste date palm leaves, in accordance with the present invention.DETAILED DESCRIPTION

[0023] In the following detailed description of the preferred embodiments, reference is made to the accompanying drawings, which form a part thereof, and within which are shown by way of illustration specific embodiments by which the disclosure may be practiced. It is to be understood that other embodiments may be utilized, and structural changes may be made without departing from the scope of the disclosure.

[0024] Some embodiments of this invention, illustrating all its features, will now be discussed in detail. The words “comprising,” “having,” “containing,” and “including,” and other forms thereof, are intended to be equivalent in meaning and be open-ended in that an item or items following any one of these words is not meant to be anexhaustive listing of such item or items, or meant to be limited to only the listed item or items.

[0025] It must also be noted that as used herein and in the appended claims, the singular forms “a,” “an,” and “the” include plural references unless the context dictates otherwise. Although any systems and methods similar or equivalent to those described herein can be used in the practice or testing of embodiments of the present invention, the preferred, systems and methods are now described.

[0026] The present invention discloses a method for manufacturing PSC boards from discarded palm fronds, specifically utilizing both the midrib and leaflets of date palm fronds, which are traditionally considered waste.

[0027] A key aspect of the invention is its commitment to sustainability and environmental responsibility. By repurposing discarded palm fronds into PSC boards, the process directly reduces waste and avoids the environmental impacts associated with traditional disposal methods such as burning or landfilling. Specifically, it addresses atmospheric pollution linked to burning and mitigates methane emissions that occur during the natural decomposition of buried palm leaves over decades.

[0028] Moreover, the PSC boards produced through this method meet stringent environmental standards by achieving a NAF rating. This is accomplished by eliminating formaldehyde-based adhesives from the manufacturing process, thereby enhancing indoor air quality and supporting healthier living environments.

[0029] Sole Figure illustrates a flow diagram, explaining method 100 for manufacturing PSC boards, which begins with processing dead palm fronds. The fronds first pass through a cleaning roller screen to remove sand, soil, and metal dust, at step 102. The leaves are passed through a specially designed Square Roller screen to remove Dust, and sand before being baled. After step 102, they pass through a metal detector to detect any metal before being baled.

[0030] At step 104, whole palm fronds, including both midribs and leaves, are collected and baled. The date palm leaves are utilized due to their unique combination of leaflets and midribs. The leaflets contribute to the board's flexibility and high modulus of elasticity, while the midribs provide essential strength. However, the method is versatile and can extend beyond date palm leaves to include other types of palm leaves. This broader application is feasible because palm leaves share mesophilic structural characteristics and belongs to the grass family, enhancing adaptability and potential for sustainable board production.

[0031] In an embodiment, the cleaned fronds are then transported to an infeed conveyor equipped with a metal detector, which identifies and removes any metal scraps that may be present. Following this, the fronds are fed into a spike roller, which grabs and feeds the material while chipping and breaking it down.

[0032] Following the baling operation, step 106 proceeds with chipping of the baled date fronds into chipped leaves and midribs, resulting in a breakdown of the palmfronds into smaller, manageable pieces necessary for further processing into PSC boards.

[0033] In an embodiment, the processed fronds are cut into 80-100 mm pieces by Chipper 1 and Chipper 2. To ensure any remaining metal scraps are thoroughly removed, the material is passed through a belt conveyor equipped with metal removal. After cutting and metal removal, the palm fronds undergo stabilization through a double screw mechanism, which ensures consistency and prepares the material for the next stage. The stabilized material is then transported to a diverter flat / chute via a conveyor belt.

[0034] The processed palm fronds are directed via a diverter flap / chute into Vibrator Conveyor 1 and Vibrator Conveyor 2. These vibrators break down the leaves and midribs to become looser, more manageable pieces before they reach the wind sifter.

[0035] At step 108, after chipping the baled fronds, a wind-sifter is used to separate the midribs from the leaves. The wind-sifter, coupled with a dust extraction system, causes the lighter material (leaves) to be blown farther away, thereby effectively separating them from the heavier material (midribs). The broken leaves are conveyed via a belt conveyor to Wind Sifter 1 and Wind Sifter 2. This segregates the components needed for the board but also ensures that dust, which can degrade board properties, is removed before further processing.

[0036] In an embodiment, after the wind sifter separates the leaves and midribs, the material is divided into two parts. The first part contains both leaves and midribs, withmidribs being in smaller quantities. The second part also contains both leaves and midribs but with a high proportion of midribs. This division simplifies the subsequent processing stages by categorizing the material based on its composition. Material from the first part is transferred via a belt conveyor and screw conveyor into a mechanical separator. This separator, featuring disk rollers and adjustable gaps, separates the leaves from the mid-ribs and fines. The mechanical separator divides the material into fines, leaves, mid-ribs, and big-leaves. The fines are classified as rejects, while the separated leaves are passed through a water bath before being transferred to the wet flake bin. Mid-ribs and large leaves are sent to Moving Floor 2. The belt conveyor and metal detector identify and reject any metal present in the mid-ribs, large leaves, and fines on the trough chain conveyor.

[0037] At step 110, after separating the leaves and midribs, the heavier midribs are collected and passed through a roller-type screen for removal of fines or oversized material from the midribs. The acceptable-size material is passed into an intermediary storage area, while any oversized material is sent back to the chipper for further size reduction. The fines separated by the roller screen can be utilized to run an energy plant and boilers in the plant within the manufacturing facility, contributing to the sustainability of the process by reusing waste materials. This ensures that only appropriately sized midribs proceed to the next stage of processing.

[0038] In another embodiment, material from the second part is transferred to a cleaning screen via a belt conveyor. The cleaning screen functions as a mechanicalseparator but does not fully separate the leaves. It divides the material into mid-ribs, ribs, leaves, fines, and oversized material. Oversized material is sent to Chipper 2 for further processing Fines separated by the cleaning screen are transferred to Moving Floor 1 and then to the trough chain conveyor via a screw conveyor. Mid-ribs and big leaves separated by the mechanical separator are transferred to the trough chain conveyor via a screw conveyor and moving floor 2.

[0039] At step 112, after removing the chipped leaves and midribs with a wind sifter, the lighter material passes through a mechanical segregator to ensure that only thin leaves go to the dryer, while lighter midribs with leaves still attached to them are further sent to a flaker at step 116, the lighter midribs with the attached leaves are sent to the flaker.

[0040] At step 114, the heavier midribs obtained from step 110 are washed to remove any kind of dust so that dust generation during flaking is reduced. In a preferred embodiment, the removal of dust and sand from the leaves is initiated by passing appropriate-sized midribs and leaves through a specially designed roller screen in order to ensure that the appropriate leaves with the appropriate thicknesses go into the board. The remaining dust and sand of the leaves undergo further removal by passing the leaves through a bath of water before going into the flaker with the larger chipped midribs. A water bath ensures thorough cleansing, preparing the leaves for subsequent processing stages in the manufacturing of the PSC boards. The above cleaning steps are crucial to maintain the quality and integrity of the final board product. The leavesare thin ranging from 0.1-0.8mm in thickness, and resemble flakes, which are typically employed in PSC boards production.

[0041] In an embodiment, the denser midribs are immersed in water for at least 15 minutes and then processed through a flaker, while the lighter and less dense leaves pass through a specially designed roller screen to ensure that only thin leaves go into the board. These thin leaves are further washed to ensure that all sand is removed and then they are dried. Soaking the midribs in water enhances their density, resulting in better flaking and reduced dust production. After soaking, the midribs were observed to increase in weight by 30%. On the other hand, the lighter and less dense leaves are excluded due to their tendency to absorb excessive water, clump together, and cause operational issues such as clogging the flaker. The chipped midribs are washed. The wet midribs are then passed through a flaker, which produces thin flakes up to 0.8 mm in thickness.

[0042] The remaining ribs and leaves then undergo chip washing to remove stones, dust, and soil. After chip washing, the remaining material is sent to the wet chips silo, which functions as both storage and a metering conveyor.

[0043] At step 118, both the lighter midribs with attached leaves from step 116 and the dust-free heavier midribs from step 114 pass through a flaker to create thin flakes. In an embodiment, the wet chips are transferred to Flakers which slice the ribs into flakes ranging from 0.7 mm to 1 mm. After slicing the ribs, the remaining material is transferred to the wet flake bin via a trough chain conveyor and a belt conveyor.

[0044] At step 120, the thin leaves obtained from step 112, and the flaked materials obtained from step 118 are passed through a dryer from a wet flake bunker. The wet flake bunker serves as storage for the flaked. This drying process is crucial for removing moisture and maintaining a moisture content of 2% from both the flaked midribs and the processed leaves, preparing them for the next stages of manufacturing the PSC boards.

[0045] In an embodiment, flakes in the wet flake bin are conveyed to the dryer via a belt conveyor. The dryer is a rotating drum with internal plates that break up the wood flakes to ensure even drying. The flakes are dried to a final moisture control of 2% with hot air. The flakes are then divided into startup flakes (which are rejected if not within tolerance) and the remaining flakes, which are transferred to a rotary screen via a trough chain conveyor. After the trough chain conveyor, the remaining flakes go through a rotary screen, which sorts them by length into categories: greater than 6 mm, 6-1.1 mm, and less than 1.1 mm (dust). Dust is removed and sent to the dust silo.

[0046] At step 122, the dried leaves and flakes undergo a process where they pass through a rotary screen. This screen is used to segregate the larger flakes from the smaller flakes and to further remove any dust remaining. The dust is subsequently directed to an energy plant and a boiler where it is utilized to generate heat used for the press and the dryer in the manufacturing process.

[0047] At step 124, the larger flake forms the surface layer in a bunker whereas the smaller flakes forms the core layer in a bunker at step 126. In an embodiment, flakeslarger than 6 mm are transferred to the Surface layer bunker via a trough chain conveyor. From the Surface layer bunker, the flakes are moved to the metering bin and then into the Surface layer drum blender. Flakes ranging from 1.1 mm to 6 mm are transferred to the Core layer drum bunker via a trough chain conveyor. From there, the flakes are directed into the metering bin and then into the Core layer drum blender.

[0048] At step 128 and 130, the larger flakes, obtained form the step 124, and smaller flakes, obtained from step 126, are simultaneously passed through separate resonators in order to control the percentage of glue on the surface layer and the core layer, respectively. In an embodiment the resonator means applying resin. In a further embodiment the dried flakes are sent to either a bunker designated for the core layer or a bunker for the surface layer of PSC boards. In these bunkers, the segregated flakes are mixed or resonated with resin. This resin coating process prepares the flakes for forming into layers within the PSC boards manufacturing process.

[0049] In an embodiment, the materials from the Surface layer drum blender and Core layer drum blender are conveyed via a trough chain conveyor to the diverter flap / chute with resin. The resin used in manufacturing the boards is preferably and predominantly pMDI. Alternatively, UF and MUF, or organic-based resins may also be used. In the preferred embodiment, pMDI is chosen for its low formaldehyde emissions, ensuring that the boards have negligible formaldehyde content.

[0050] At step 132, after applying resin on the larger flakes obtained at step 128 and the smaller flakes obtained at step 130, the resonated flake gets collected and formbunkers. In a preferred embodiment, the resonated flakes are stored in the Surface layer bunker and core layer bunker.

[0051] At step 134, the resonated material is passed through two forming heads with mechanical separators for forming a matt comprising of the surface layer (bottom) made of larger flakes, and a core layer made of smaller flakes and surface layer (top). The diverter directs the materials via swivel belt conveyor to the forming bunkers. The materials in the forming bunkers are then segregated once again (through a mechanical segregator), in order to form the surface layer (bottom), the core layer (from the forming head at the back) and core layer, surface layer (top) (from the forming head at the front. And subsequently to the forming line-forming belt.

[0052] At step 136, the formed matt of step 134 is passed through a Continuous Pressing System (CPS) to form boards. In the CPS, the mat is pressed to its final thickness using pressure and heat. In an embodiment, the formed Matt is then transported via a belt through a metal detector set to the appropriate size. The belt ensures that the density profile of the matt is adjusted using online scales. Subsequently, the sheets proceed to a press. Once pressed, the sheets emerge from the press as boards and are cut to the correct length by a moving saw.

[0053] At step 138, the formed boards at step 136 are cut to the required length. In a preferred embodiment, the boards are cut into 8x8-foot boards by a diagonal saw. Leftover mat pieces, including cut and end pieces, are classified as rejects. Any unwanted material is also rejected by the online quality control system.

[0054] At step 140 allowing the boards to cool by stacking them onto a star cooler. The boards then enter a star cooler to facilitate cooling. After cooling in the star cooler, the boards can be cut to the desired dimensions on the production line. The cooled boards are shaped using a split-cut saw.

[0055] At step 142 the boards are sent to a stacker and removed from the line and stored.

[0056] The advantages set forth above, and those made apparent from the foregoing description, are efficiently attained. Since certain changes may be made in the above construction without departing from the scope of the invention, it is intended that all matters contained in the foregoing description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

[0057] It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described, and all statements of the scope of the invention that, as a matter of language, might be said to fall there between.

Claims

I / We Claim:1) A method of manufacturing palm sequestered carbon (PSC) boards out of waste date palm leaves, comprising the steps of: baling palm fronds into bales; chipping baled fronds to obtain chipped leaves and midribs; sifting chipped leaves and midribs to separate the leaves from the midribs; collecting heavier midribs and passing them through a roller-type screen to remove fines or oversized material; washing the chipped midribs of acceptable size; passing the lighter material through a mechanical segregator; passing the lighter leaves through a water bath and then onto the dryer; passing the heavier midribs onto the chipwash and then flaker passing the dried leaves and flakes through a roller-type screen to segregate larger flakes from smaller flakes and remove dust; resonating the segregated flakes with resin; and forming layers of palm strands by passing the flakes through forming heads.2) The method as claimed in claim 1, the method comprises cleaning of the fronds.3) The method as claimed in claim 1, the method further comprises passing the wet chipped midribs through the flaker producing wet midrib flakes from the chipped midribs.4) The method as claimed in claim 1, the method further comprises processing the leaves through a specially designed roller screen to ensure that only the thin leaves go into the board.5) The method as claimed in claim 1, wherein the said resin is pMDI, optionally UF and MUF, or organic-based resins.6) The method as claimed in claim 1, wherein the sheets are cut to size and compressed to form PSC boards using a plurality of such sheets.7) The method as claimed in claim 1, wherein each of the PSC boards is cooled following cutting.8) The method as claimed in claim 1, wherein the removing step comprises removing remaining dust and sand by passing the leaves through a bath of water.9) A PSC board manufactured according to the method of any one of claims 1 to 5.

Images