Method for manufacturing a fuel product for a boiler

Abstract

The present invention relates to a fuel product for a boiler, the fuel product resulting from the mixing and compacting of lignocellulosic materials, wherein the lignocellulosic materials have a proportion PC by weight (relative to the total weight of the fuel product for a boiler) of lignocellulosic materials derived from at least one European and / or tropical / desert cane such that 20 ≤ PC ≤ 50%.

Description

METHOD FOR MANUFACTURING FUEL PRODUCT FOR BOILERS

[0001] This patent application claims priority from French patent application FR 2414785 filed on 19 / 12 / 2024, which is hereby incorporated by reference. Scope of the invention

[0002] The present invention relates to a process for producing solid fuels for energy applications and, more specifically, a process for manufacturing boiler fuel products incorporating lignocellulosic material from European and / or tropical / desert canes. State of the art

[0003] As climate challenges become increasingly urgent, global energy policies are turning more and more towards renewable energy. These clean alternatives aim to significantly reduce carbon dioxide emissions, a major contributor to accelerating global warming. Solar, wind, hydropower, and biomass combustion are thus identified as crucial drivers of this energy transition.

[0004] For these reasons, authorities are encouraging the development of renewable energies to reduce CO2 emissions, the main cause of global warming. Among the expanding renewable energy sources are solar, wind, hydropower, and biomass combustion. This last category generally includes biofuels and boiler fuels such as wood or biofuels, usually derived from agricultural by-products or residues from the agri-food industry. Faced with the gradual depletion and rising cost of fossil fuels such as oil, many individuals and communities are now opting for heating with such fuels, which then requires specific boilers.

[0005] These boilers, which use specific fuel products, generally wood-based, are sophisticated and offer very high efficiency. The production of these boiler fuels, while technically complex, is now crucial for the industry due to the growth of this market. Today, the use of boilers fueled by these products in homes, industries, and local communities is increasing because of their advantages: efficient combustion without smoke emissions, an economical alternative to fuel oil and gas, and an environmentally sound solution.

[0006] Now, these boiler fuel products are mainly made from wood residues and it is difficult to obtain products of satisfactory quality using other plants that do not contain wood.

[0007] The production of these boiler fuels allows for a considerable reduction in the volume of raw materials used, thus optimizing the storage and transport possibilities of this energy source. Although numerous processes are known for manufacturing these boiler fuels, their implementation often requires the use of energy-intensive machinery, particularly during biomass drying.

[0008] It is known that the use of European and / or tropical / desert sugarcane presents significant challenges, particularly the production of products that do not meet regulations. For example, the combustion of European and / or tropical / desert sugarcane can generate high ash content as well as corrosion and wear problems in boiler mechanisms. Summary of the invention

[0009] The inventor demonstrated that a specific boiler fuel product (REEDS PELLETS or BIOFERME PELLETS), which uses lignocellulosic materials derived from European and / or tropical / desert sugarcane, has a particularly low carbon footprint due to the low carbon dioxide emissions during combustion, while also boasting a calorific value as high as that of much more expensive softwood pellets. Finally, such a fuel product for The boiler also has a minimal environmental impact, benefiting from short supply chains that minimize logistical requirements and promote a circular economy. Furthermore, the use of such lignocellulosic materials derived from sugarcane makes it easy and cost-effective to lower the moisture content of the materials to be compacted, thus reducing the carbon footprint of the manufacturing process for this boiler fuel.

[0010] Consequently, a first object according to the invention consists of a method for manufacturing a combustible product for boilers comprising the steps of:

[0011] A) mixing lignocellulosic materials,

[0012] B) grind the mixture obtained at the end of step A)

[0013] C) compact the ground material obtained in step B) to obtain a combustible product for boilers,

[0014] where the lignocellulosic materials have a PC proportion by weight (relative to the total weight of the boiler fuel product) of lignocellulosic materials from at least one European and / or tropical / desert cane such as 20 <PC<50 %.

[0015] The inventor demonstrated that such a proportion of lignocellulosic materials makes it possible to obtain a compacted product with a very good calorific value. As long as this product incorporates a minimal proportion of wood, its properties are ideal in that it meets current standards for fines content and durability, while still exhibiting a high calorific value and a low manufacturing cost.

[0016] Similarly, the inventor demonstrated that it is possible to obtain, even without the addition of glue and on an industrial scale, combustible (compacted) boiler products that fully comply with regulations (something that had never been achieved before), particularly in terms of their durability and fines content. Obtaining such a product is primarily a result of the significant temperature increase observed during the compaction stage (which can reach a value of 130°C) within the press. This temperature allows the production of a denser and more resistant product, probably due to the modification of the lignin structure at this temperature which, by melting slightly, acts as a natural binder between the lignocellulosic materials.

[0017] Preferably, lignocellulosic materials include at least wood, ideally a proportion of PB by weight (relative to the total weight of the boiler fuel) such as 20 <PB<80 %, de préférence 30<PB<60 %.

[0018] The inventor demonstrated that a minimal proportion of softwood allows for improved compaction.

[0019] Preferably, the lignocellulosic materials comprise a PBR proportion by weight of softwood (relative to the total weight of the boiler fuel product) of at least 5%, preferably at least 10% and, particularly preferably, at least 20%.

[0020] The inventor has demonstrated that carrying out step B) of high-speed grinding of this specific mixture significantly increases the temperature of this mixture, which temperature increase is much greater than that obtained with mixtures conventionally used to manufacture boiler fuel products and makes it possible to significantly lower the moisture content.

[0021] Preferably, this grinding step B) is carried out at a speed which results in a ground product at the end of which has a temperature greater than or equal to 30°C, typically between 30°C and 70°C, preferably greater than or equal to 40°C, typically between 40°C and 60°C, and, particularly preferably, equal to 50°C ± 5°C.

[0022] A second object of the invention relates to a combustible product for boilers obtained or capable of being obtained by the process described above.

[0023] A third object of the invention relates to a bag of combustible products for boilers obtained or capable of being obtained by the process described above.

[0024] A fourth object of the invention relates to the use of lignocellulosic materials for the manufacture of a boiler fuel product, which lignocellulosic materials have a PC proportion by weight (relative to the total weight of the boiler fuel product) of lignocellulosic materials derived from at least one European and / or tropical / desert sugarcane such as 20 <PC<50 %.

[0025] A fifth object of the invention relates to a high-speed crusher and its use for crushing a mixture of lignocellulosic materials for the purpose of manufacturing a boiler fuel, which mixture has a PC proportion by weight (relative to the total weight of the boiler fuel) of lignocellulosic materials from at least one European and / or tropical / desert sugarcane such as 20 <PC<50 %.

[0026] A sixth object of the invention relates to a press and its use for compacting the ground material of a mixture of lignocellulosic materials for the purpose of manufacturing a boiler fuel, which mixture has a PC proportion by weight (relative to the total weight of the boiler fuel) of lignocellulosic materials from at least one European and / or tropical / desert sugarcane such as 20 <PC<50 %. Description of the figures

[0027] Figures 1 and 2 show side and top views respectively of an installation for the manufacture of a boiler fuel product comprising in a mixer, a high-speed crusher and a press.

[0028] Figures 3 and 4 show side and top views respectively of a dual-axis mixer.

[0029] Figure 5 shows side and top views of a high-speed crusher. Figure 6 shows side and top views of a WIESENFIELD WIE-PM-1500 press Detailed description

[0030] The term "boiler fuel" refers to a "solid biofuel," which is a solid fuel (energy carrier intended for energy conversion) produced directly or indirectly from biomass (material of biological origin), (e.g., briquettes). Preferably, "fuel product" refers to a "solid biofuel" as defined by ISO 16559 and, where applicable, by ISO 17225-1 (and associated standards related to solid biofuels (e.g., ISO 17225-1, ISO 17225-2, ISO 17225-4, ISO 17225-6:2021, ISO 17225-8, ISO 17225-9, etc.)).

[0031] Advantageously, the boiler fuel product is a compacted fuel product and is advantageously chosen from the group including boiler fuel products (pellets), logs, briquettes (small logs), bundles or paving stones.

[0032] Preferably, the fuel product for the boiler is a pellet (sometimes called "pellet"), which can take multiple forms (circular, cylindrical, cubic, etc.).

[0033] Now, such a boiler fuel product will preferably be cylindrical in shape and typically have a length between 2 and 50 mm, preferably between 3.15 and 40 mm. Furthermore, such a boiler fuel product will typically have a diameter less than or equal to 40 mm, preferably less than or equal to 25 mm. Preferably, such a boiler fuel product has a diameter ranging from 4 to 8 mm, preferably ranging from 5 to 7 mm.

[0034] Compacted fuel product is defined as a boiler fuel product obtained after a compaction step (pressing or compacting) of a mixture of lignocellulosic materials, which boiler fuel product then has a density greater than or equal to 500 kg / m³ 3 , typically ranging from 500 to 950 kg / m 3 , preferably with a density greater than or equal to 600 kg / m³ 3 (as specified in ISO 17225-6:2021 for boiler fuel products), which density is typically between 600 and 850 kg / m³ 3 .

[0035] Such a compacted combustible product must also exhibit satisfactory durability. Durability of a compacted combustible product refers to the mechanical property that characterizes its resistance to fragmentation under shock and abrasion stresses that may occur during handling and transport (durability is defined in standard NF EN ISO 17831-1). This durability value can be quantified by measuring the percentage of compacted combustible products remaining intact after being subjected to a mechanical resistance test specified by ISO 17831-1. In short, the measurement method uses a durability tester, which essentially consists of a drum in which the compacted combustible products are rotated and which is equipped with a deflector to simulate the actual mechanical stress conditions that these products might encounter in practical use.At the end of the rotation, the compacted fuel products are sieved to isolate and weigh the resulting (fine) particles. The durability value then corresponds to the percentage (by weight) of unfragmented compacted fuel products (relative to the initial weight of the compacted fuel products). Preferably, the boiler fuel product has a durability of 90% or higher, typically 95% or higher, and, most preferably, 97.5% or higher.

[0036] Typically, the compacted combustible product will exhibit the characteristics detailed in Table I.

[0037] [Table 1]

[0038] The term "lignocellulosic material" refers to a material based on lignocellulose. Lignocellulose is a mixture of lignin, hemicellulose, and cellulose. These components give specific physical and chemical properties to each type of plant. The proportions of such a mixture will vary depending on the plant. Among these components, lignin is of particular interest. Specifically, lignin is not a single molecule, but rather a class of highly cross-linked, amorphous aromatic macromolecules that play a key role in the formation of cell walls in wood and bark (for a detailed description, see ISO 16559). Therefore, it is lignin that gives cell walls, and more generally, plants as a whole, their strength and rigidity.

[0039] Advantageously, lignocellulosic materials are selected from the group consisting of plant by-products, natural wood by-products (sawdust, chips, shavings), or wood waste and sawdust, wood particles, and mixtures thereof. Plant by-products are well known to those skilled in the art and include, in particular, green waste, corn cobs, cereal straw, rice husks, beet leaves, wheat husks, sunflower hulls, sugarcane bagasse, grape pomace, vine shoots, and coffee grounds, used alone or in mixtures. Green waste refers to organic residues from plant sources. Examples include, but are not limited to, fallen leaves, grass clippings, tree branches, trunks, pruning waste from hedges or shrubs, and other plant debris.

[0040] Generally speaking, "lignocellulosic material" means material which includes a proportion by weight of lignin greater than or equal to 10% (relative to the total weight of dry matter), preferably greater than or equal to 15%.

[0041] Preferably, the lignocellulosic materials used should have a size of 20 cm or less, and preferably 15 cm or less. If a lignocellulosic material is larger (and does not conform to this specification), it will simply need to be ground beforehand to meet these requirements.

[0042] Preferably, the lignocellulosic materials used should have a moisture content of 50% or less (by weight), and preferably 40% or less. If a lignocellulosic material has a higher (and non-compliant) moisture content, it should simply be dried beforehand to meet these specifications. This can be achieved, for example, by simply placing the material under cover for the required time (3, 4, 5, 6 weeks or more) to reach the desired moisture content.

[0043] Now, the compacted mixture of lignocellulosic materials according to the invention will necessarily include wood in order to obtain a product of optimal quality.

[0044] Advantageously, the compacted mixture of lignocellulosic materials comprises at least some wood. Typically, such a mixture will have a PB proportion by weight (relative to the total weight of the boiler fuel) such that 20 <PB<80 %, de préférence 30<PB<60 %.

[0045] Wood, as a lignocellulosic material, can be sourced from green waste (for example, through sorting or screening) as well as from wood industry waste (branches (from the forestry industry), bark (from sawmills or paper mills), sawdust (from sawmills), etc.) or used wood. When identifying wood within green waste, it is typically obtained by sorting this green waste at a sorting / transit platform, which also allows for the removal of unwanted elements (stones, scrap metal, plastic bags).

[0046] The wood used may come from any woody plant and, for example, may come from resinous trees (or conifers, for example pines, thujas, firs, etc.) or from deciduous trees (as opposed to conifers or resinous trees, for example poplars, birches, oaks, beech, ...).

[0047] The wood used must have a moisture content of 35% by weight or less, preferably 30% by weight or less. If the wood has a higher (and non-compliant) moisture content, a further adjustment will be necessary. A preliminary drying step is required for this wood to meet these specifications. For example, this drying step could be carried out by sheltering it, but also by using a drum dryer.

[0048] The wood used must be 15 cm or less in size, preferably 10 cm or less, and particularly 5 cm or less. If the wood is larger (and does not conform to these specifications), it will simply need to be pre-shredded to meet these requirements. This pre-shredding can be carried out using a shredder familiar to those skilled in the art (e.g., KAHL shredders), typically a knife shredder (e.g., BOSCH AXT 25 TC). If necessary, this step can involve several shredding stages, using successive shredders with increasing shredding capacity. For example, such additional shredding can be carried out using a hammer mill (e.g., WIESENFIELD WIE-PM-400).

[0049] In the case where the wood used is in the form of chips, these shall have a diameter less than or equal to 10 cm, preferably less than or equal to 5 cm.

[0050] It has now been demonstrated that the compacted mixture according to the invention will exhibit improved properties when it includes a minimum of softwood.

[0051] According to one embodiment of the invention, the compacted mixture of lignocellulosic materials comprises at least 2% by weight of softwood (relative to the total weight of the boiler fuel product), preferably at least 5% and, particularly preferably, at least 10% by weight of softwood.

[0052] By "European and / or tropical / desert cane," we mean:

[0053] 1) all plants belonging to the Poaceae family (grasses) whose stems are hard and greater than 1 meter and whose annual biomass growth exceeds 3 tonnes per hectare, which allows strong carbon sequestration because they generally belong to the so-called C4 plant categories.

[0054] 2) plants also exhibiting strong development of underground roots because all these plants have rhizomes and can withstand immersion in water varying between 10 cm and 1 meter depending on the species (which is not the case for bamboos which cannot withstand strong hydraulic variations).

[0055] 3) Plants whose rhizomes are also characterized by their ability to adapt to variations in the levels of organic filters, which allows filters to be loaded with up to a maximum thickness of 1.5 meters of organic substrate if necessary

[0056] 4) These plants also produce, after drying, culms rich in woody matter (over 90% of the dry matter) and low in moisture (10 to 15% depending on the species, whereas short-rotation coppice willows have moisture levels exceeding 20 or 30%). All these canes therefore have significant potential for utilizing their biomass as energy due to their higher calorific value (LHV) than wood (between 4000 and 5000) and the non-rottable nature of their culms (which often leads to their use as building materials for thatched roofs, for example).

[0057] 5) Finally, plants that exhibit a high evapotranspiration capacity, exceeding 4 mm per day per m² 2

[0058] Lignocellulosic materials from European and / or tropical / desert canes have a size between 0.1 cm and 5 cm, preferably between 0.3 cm and 4 cm and, particularly preferred, a size between 0.5 cm and 3 cm.

[0059] Such lignocellulosic materials derived from European and / or tropical / desert sugarcane are obtained simply, notably by crushing such sugarcane or by screening sugarcane debris.

[0060] According to one embodiment, the lignocellulosic materials derived from European and / or tropical / desert sugarcane have a moisture content of 30% or less, preferably 25% or less. If these lignocellulosic materials have a higher (and non-compliant) moisture content, it It will simply be necessary to carry out a preliminary drying step of these lignocellulosic materials in order to meet these specifications.

[0061] Avantageusement, la dite au moins une canne européenne et / ou tropicale / désertique est choisie dans le groupe comprendre Acorus Calamus, Amnophila arenaria, Ampelodesmos mauritaniens, Andropogon gerardii, Arundo donax sensu, Bromus inermis, Calamagrostis acutiflora, Calamagrostis arundinacea, Carex morrowii, Carex pendula, Chasmanthium latifolium, Chionochloa conspicua, Chusquea culeou, Colocasia esculenta, Cortaderia fulvida, Cortaderia richardi, Cortaderia selloana, Cymbopogon citratus, Cyperus ensiatus, Cyperus giganteus, Cyperus longus, Cyperus papyrus, Deschampsia cespitosa, Elegia capensis, Equisetum americanum, Winter equisetum, Equisetum fluviatile, Equisetum maximus, Fargesia murielae, Fargesia nitida, Glyceria maxima, Hibanobambusa tranquillans, Indocalamus solid, Indocalamus tessellated, Juncus acutus, Juncus effusus, Leymus arenarius, Miscanthus sinensis and var., Miscanthus jloridulus, Miscanthus sacchariflorus, Miscanthus giganteus, Molinia altissima, Molinia arundinacea, Molinia caerulea, Panicum virgatum, Panicum rigidulum, Papyrus papyrus, Pennisetum et var., Phalaris arundinacea, Saccharum arundinaceum, Saccharum officinarum, Saccharum ravennae, Schoenoplectus californiens, Schoenoplectus tabernaemontanis, Scirpus lacustris, Sorghum halepeus, Spartina alterniflora, Sponiopogon sibiricus, Stipa calamagrostis, Stipa splendens, Typha minima, Thysanolaena latifolia, Typha domingensis, Zizania aquatica, Zizania latifolia and Zizania palustris.

[0062] De façon préférence, la dite au moins une canne européenne et / ou tropicale / désertique est choisie parmi Miscanthus giganteus, Phragmite australis et Arundo donax.

[0063] In addition to lignocellulosic materials, the boiler fuel product according to the invention may include other components, such as impurities associated with these materials (e.g., gravel) or additives (e.g., binder).

[0064] An additive is a component that improves the quality of the boiler fuel product (for example, combustion properties or durability), reduces emissions, or contributes to production profitability. The additive is described in more detail in ISO 16559. A person skilled in the art can easily identify the additives of interest. For example, potato or corn starch can be used as a binder, or the combustion additive described in French patent FR 2953852 B1 can be used to improve performance and prevent the formation of clinker and corrosive fumes.

[0065] According to another preferred embodiment, the boiler fuel product according to the invention comprises at least one additive, typically between 0.5 and 10% by weight (relative to the total weight of the product), preferably between 1 and 5% by weight.

[0066] In this case, the boiler fuel product according to the invention comprises at least 90% by weight of lignocellulosic materials, preferably at least 95% by weight of lignocellulosic materials and, particularly preferably, at least 98% by weight of cellulosic raw materials.

[0067] According to an alternative preferred embodiment, the boiler fuel product according to the invention does not include any additives.

[0068] In this case, the boiler fuel product according to the invention comprises at least 98% by weight of lignocellulosic materials, preferably at least 99% by weight of lignocellulosic materials and, particularly preferably, 100% by weight of cellulosic raw materials.

[0069] In connection with step A of the process, this mixing step is carried out using techniques / equipment well known to those skilled in the art, typically using mixers (examples: mixers from KAHL). This step makes it possible to obtain a homogeneous mixture.

[0070] Such a mixer will advantageously have a total volume greater than 500 liters, preferably greater than 1000 liters and, particularly preferably, a total volume greater than 1200 liters.

[0071] Typically, such a mixer will advantageously offer an effective working capacity of over 200 kg of mixture per cycle, preferably a capacity of effective working capacity of more than 600 kg of mixture per cycle and, particularly preferred, an effective working capacity of more than 1000 kg of mixture per cycle.

[0072] In addition, the mixer can be equipped with extra features such as cleaning systems and / or at least one control panel. These features allow for precise adjustment of cycles and speed, as well as real-time monitoring of parameters.

[0073] To be carried out optimally, the following step B) of grinding must use a mixture of lignocellulosic materials with a moisture content of less than or equal to 20% (by weight relative to the total weight of the mixture).

[0074] To achieve this, the moisture content of the mixture obtained at the end of step A) can be lowered by storing the mixture under cover for the required period (e.g., 2, 3, 4, 5 weeks or more). Alternatively, this moisture content can be lowered rapidly to allow immediate commencement of step B) grinding by simultaneously drying the mixture using techniques / equipment well-known to those skilled in the art, typically a drying mixer (e.g., a KAHL brand).

[0075] Now, the inventor has highlighted that the use of lignocellulosic materials from European and / or tropical / desert cane makes it easy and quick to lower the moisture content of the mixture made in step A). ​​Indeed, the moisture content of this type of lignocellulosic material is very low, so that with the small proportion of it in the mixture, the moisture content of the mixture is reduced quickly without drying, or with a drying step that is much faster and much more energy-efficient than traditional processes using rotary drying screens, which are more suited to biomass from wood chips that are generally very moist.

[0076] According to a preferred embodiment of the process according to the invention, step A) thereof consists of mixing and drying said lignocellulosic materials.

[0077] Typically, this step is then carried out by performing this mixing step at a temperature between 40°C and 80°C, preferably between 50°C and 70°C.

[0078] As an example, this step A) is typically carried out for a duration of between 1 and 30 minutes, preferably between 1 and 15 minutes. This duration may be adjusted according to the proportion of lignocellulosic materials derived from European and / or tropical / desert sugarcane. A mixing time of 10 minutes will be satisfactory for a mixture containing 20% ​​lignocellulosic materials from sugarcane, while only 5 minutes will be sufficient for a mixture containing 50% lignocellulosic materials from sugarcane.

[0079] Preferably, this step A) is carried out until a mixture is obtained with a moisture content of less than or equal to 25% (relative to the total weight of the mixture), preferably a moisture content of less than or equal to 20% (relative to the total weight of the mixture).

[0080] To do this, this step simply incorporates monitoring of the humidity level, which is carried out using devices well known to those skilled in the art (e.g., moisture meter) within the mixing (and possibly drying) equipment.

[0081] In connection with step B) of the process, this grinding step is carried out using techniques / equipment well known to those skilled in the art, typically using rotary mills (examples: KAHL brand rotary mills). This step produces a ground material whose particles can be efficiently compacted in step C.

[0082] Such a crusher will advantageously produce a quantity of crushed material of at least 500 kilograms per hour, preferably at least 1,000 kilograms per hour, and particularly preferably between 2,500 and 10,000 kg per hour.

[0083] Advantageously, the particle size of the ground material obtained at the end of step B) is less than or equal to 25 mm, generally between 10 mm and 25 mm, preferably less than or equal to 20 mm, generally between 12 mm and 20 mm, and particularly preferably less than or equal to 17 mm, generally between 13 mm and a maximum of 17 mm.

[0084] To do this, the duration of this step B) will be adjusted according to the particle size of the ground material. Typically, this adjustment is made by integrating, within a grinder, i) at least one means of measuring the particle size of the ground material and ii) to at least one control system coupled to this i) at least one means for measuring the particle size of the ground material and to iii) at least one means for rotating the mill, which ii) at least one control system determines the activation or deactivation of this iii) at least one means for rotating the mill so that the ground material at the end of step B) of grinding has the desired particle size.

[0085] Advantageously, this grinding step B) is carried out at high speed.

[0086] Indeed, the inventor demonstrated that performing this high-speed grinding step on this specific mixture significantly increases its temperature, a temperature increase far greater than that obtained with mixtures typically used to manufacture boiler fuels. Consequently, the ground material has a reduced moisture content, potentially as low as 9% or even 6%, and this step therefore incorporates drying, occurring simultaneously with the grinding.

[0087] Preferably, this grinding step B) is carried out at a speed which results in a ground product at the end of which has a temperature greater than or equal to 30°C, typically between 30°C and 70°C, preferably greater than or equal to 40°C, typically between 40°C and 60°C, and, particularly preferably, equal to 50°C ± 5°C.

[0088] To do this, the rotation speed during this step B) will be adjusted according to the temperature of the mixture. Typically this adjustment is made by integrating, within a mill, iv) at least one temperature probe (allowing the temperature of the ground material to be determined) and ii) at least one control system coupled to this iv) at least one temperature probe and to T iii) at least one means of rotation of the mill, which ii) at least one control system adjusts the rotation speed of this iii) at least one means of rotation of the mill so that the temperature of the ground material (as measured by the iv) at least one temperature probe) has the desired value (see above).

[0089] Preferably, the duration of this step B) is also adjusted to obtain a ground product which, in addition to having a particle size such as is targeted previously, also has a moisture content of less than or equal to 20% (relative to the total weight of the mixture), preferably a moisture content of less than or equal to 15% (relative to the total weight of the mixture).

[0090] To be carried out optimally, the following compaction step C) must use ground material with a moisture content of less than or equal to 16% (by weight relative to the total weight of the mixture).

[0091] If such a moisture level can be obtained by integrating an additional drying step of the ground material between steps B) and C) (see above for drying), it is also possible to adjust the duration of this step B) according to the size of the particles of the ground material, but also the moisture level of this ground material in order to get closer to the desired moisture level.

[0092] Advantageously, the rotation time during this step B) is determined by the particle size of the ground material, but also by the moisture content of this ground material. Typically, this adjustment is made by integrating, within a mill, v) at least one means for measuring the moisture content of the ground material (allowing the moisture content of the ground material to be determined, e.g., a moisture meter) and ii) at least one control system coupled to this v) at least one means for measuring the moisture content of the ground material and to T iii) at least one means for rotating the mill, which ii) at least one control system determines the activation or deactivation of this iii) at least one means for rotating the mill so that the ground material at the end of grinding step B) has, in addition to the desired particle size, also the desired moisture content.

[0093] Typically, this grinding step B) uses a rotary mill, preferably a rotary knife mill.

[0094] In a high-speed grinding step B), the rotary mill will use a rotational speed greater than or equal to 2,000 revolutions per minute, preferably between 2,000 and 7,000 revolutions per minute and, particularly preferably, between 2,000 and 5,000 revolutions per minute.

[0095] Due to the increased heating resulting from the characteristics of the mixture, but also from the hardness characteristics of the lignocellulosic materials derived from of canes (due to their high silica content), this crushing step is likely to cause rapid wear of the equipment used in this step B).

[0096] In addition to its high rotational speed, the rotary knife mill used in this step B) will preferably have knives with:

[0097] - The blade length varies between 21 and 35 cm, preferably between 22 and 30 cm.

[0098] - the hardness varies between 25 and 35 HRC, preferably between 30 and 35 HRC.

[0099] Compared to the knives of conventional rotary knife mills (length up to 20 and hardness between 20 and 25 HRC), the use of such improved rotary knife mills allows for a real industrial implementation of this step B), which is otherwise impossible with such conventional rotary mills.

[0100] Such blade hardness is typically obtained with steel containing a chromium content of around 12%, giving the blade very good resistance to impacts and abrasion.

[0101] Advantageously, the rotary knife mill used in this step B) will also have a number of knives greater than or equal to 30, preferably between 30 and 52 knives.

[0102] Compared to conventional rotary knife mills, which include up to 25 knives, the use of such improved rotary knife mills makes it possible to further improve the industrial efficiency of this step B), which is otherwise impossible with such conventional rotary mills.

[0103] Advantageously, the knives of such a rotary knife grinder are always easily interchangeable, always with a view to maintaining constant efficiency.

[0104] In connection with step C) of the process, this compaction step is carried out using techniques / equipment well known to those skilled in the art, typically using a press (e.g., KAHL or WIESENFIELD WIE-PM-1500 presses). This step yields a combustible product for boilers whose characteristics comply with ISO 17225-6:2021 standards (size, moisture content, density, etc.).

[0105] Such a press will advantageously produce a quantity of boiler fuel products of at least 500 kilograms per hour, preferably at least 1,000 kilograms per hour, and particularly preferably between 1,500 and 3,000 kg per hour.

[0106] The inventor has now demonstrated that performing step C) of compacting the ground material obtained at the end of step B) results in a significant temperature increase within the press (during step C). This temperature can reach 130 degrees Celsius inside the press. This temperature is considerably higher than that obtained with mixtures typically used to manufacture wood pellet-type boiler fuels.

[0107] Now, this temperature increase is favorable to obtaining a compacted product, particularly due to the modification of the lignin structure, which, by melting slightly, acts as a natural binder between the lignocellulosic materials. In fact, this temperature helps to obtain a denser and more resistant boiler fuel at the end of step C).

[0108] However, this high temperature leads to significant vaporization of the moisture in the ground material, resulting in a reduced moisture content. It is therefore essential to manage the evacuation of this water vapor within the press to prevent the risks of overpressure and corrosion.

[0109] Advantageously, the press used for implementing step C) includes at least one means for removing water vapor. Typically, this at least one means for removing water vapor takes the form of a grid, which can be coupled to an extraction fan.

[0110] Furthermore, due to the high temperature reached by the crushed material during compaction, it is recommended to cool the resulting product at the end of this stage. Cooling is preferable to allow safe storage of the product obtained and to prevent any risk of spontaneous combustion.

[0111] Preferably, this compaction step C) is carried out so as to obtain at its end a combustible boiler product with a temperature of less than or equal to 60°C, preferably less than or equal to 50°C, and particularly preferably less than or equal to 40°C.

[0112] To do this, the temperature of the boiler fuel products is adjusted at the end of step C). Typically, this adjustment is done by integrating, at the outlet of the press, i) at least one cooling means (allowing the boiler fuel products to be cooled).Now, the press used may include in addition to i) at least one cooling means, ii) at least one means for measuring the temperature of the boiler fuel products after compaction and iii) at least one control system coupled to this ii) at least one temperature measuring means and to this i) at least one cooling means, which ii) at least one control system determines the activation or deactivation or adjusts the intensity of operation (and therefore cooling) of this i) at least one cooling means, so that the boiler fuel products at the end of step C) (after compaction) have the desired temperature.

[0113] As an example, the cooling method could take the form of an oil cooling system, with, for example, a small radiator, which is arranged so that the oil temperature can decrease from 85°C to 30°C.

[0114] In the end, the boiler fuel product obtained at the end of step C) has a particularly low moisture content.

[0115] Advantageously, this compaction step C) is carried out so as to obtain at its end a combustible product for boilers having a moisture content of less than or equal to 15% (relative to its total weight), preferably less than or equal to 12% and, particularly preferably, less than or equal to 10%.

[0116] While the products obtained at the end of step C typically have this moisture content, it is nevertheless possible to adjust step C) of compaction, which is associated with an increase in temperature, and in particular its duration, to the moisture content of the ground material being compacted. Typically, this adjustment is made by integrating, within the press, i) at least one means of measuring moisture (allowing the moisture content of the ground material to be determined, e.g., a moisture meter) and ii) at least one control system coupled to this i) at least one means of measuring moisture and iii) at least one means of compacting the ground material and also to iv) at least one means of evacuating water vapor, which ii) at least one control system determines the activation or deactivation of this iii) at least one means of compacting the ground material and of this iv) at least one means of evacuating water vapor, so that the boiler fuel products at the end of step C) have the desired moisture content.

[0117] According to a particular embodiment of the invention, the press comprises at least one rotor, with at least two rollers and a die having a plurality of holes. In a known manner, the rollers are adjusted to regulate the density and shape of the compacted boiler fuel products obtained.

[0118] Advantageously, said at least one rotor is equipped with specific blades and / or vanes. This at least one rotor allows for the continuous and homogeneous feeding of crushed material into the press so as to ensure a continuous and efficient compaction stage. Typically, the at least one rotor rotates at a speed of 200 to 800 rpm, preferably at a speed of 300 to 700 rpm, and particularly preferably at a speed of 400 to 600 rpm.

[0119] Advantageously, the die is designed to be interchangeable and can be adapted to a variety of hole sizes depending on the size of the desired boiler fuel products. Advantageously, this die has holes with diameters ranging from 2 mm to 30 mm, preferably from 4 mm to 25 mm, and particularly preferably from 6 mm to 20 mm.

[0120] Advantageously, the pressure setting in said press is achieved via adjusting the distance between the rollers and the die as well as by modifying the rotation speed of at least one rotor.

[0121] Such a press will advantageously produce a quantity of boiler fuel product of up to 0.6 tonnes per hour, preferably up to 1 tonne per hour, and particularly preferably up to 1.5 tonnes per hour.

[0122] According to a particular embodiment of the process of the invention, it may include a step D), following step C), of drying the boiler fuel products obtained at the end of step C).

[0123] Such a step makes it possible to obtain, if needed, such boiler fuel products with the desired moisture content mentioned previously.

[0124] To achieve this, a drying ventilation system can be used. Typically, such a system uses a precisely regulated flow of hot air to remove residual moisture from the boiler fuel products and achieve the desired moisture content. The goal is to optimize the quality of the boiler fuel products in terms of calorific value and physical stability for subsequent storage or transport.

[0125] The drying ventilation system will allow the boiler fuel products to be spread evenly, for example on a perforated conveyor, so as to allow optimal exposure to hot air and to ensure homogeneous drying of all the boiler fuel products.

[0126] According to another particular embodiment of the process of the invention, it may include a step E), following step C) and possibly D) if present, of bagging the combustible products for boilers.

[0127] In this final step, the boiler fuel products are simply transferred to a bagging station. This step E) uses a bagging machine, preferably automatic (e.g., Premier Tech Chronos E55 Series), which is designed to automatically fill bags.

[0128] Such a bagging machine incorporates a weighing system to ensure that each bag is filled with the same predetermined quantity of boiler fuel products, corresponding to pre-established specifications. Each bag is then sealed by A secure locking mechanism ensures the integrity and protection of boiler fuel products during transport and storage. This process is essential for maintaining the quality and hygiene of the biofuel, preventing contamination and degradation.

[0129] At the end of this bagging step E), the bags of boiler fuel products have a weight greater than or equal to 5 kg, preferably greater than or equal to 10 kg and, particularly preferably, greater than or equal to 20 kg.

[0130] Such a bagging step E) is particularly suitable for industrial and commercial customers seeking large quantities of products for use or marketing in the short or long term, thus ensuring efficient and economically advantageous distribution.

[0131] The following examples are provided for illustrative purposes only and are not intended to limit the scope of the present invention.

[0132] 1) Preliminary study on Miscanthus sisanteus and characterization of lignocellulosic materials

[0133] In order to carry out a comprehensive evaluation of a combustible product, it is imperative to understand in detail the influence of physico-chemical properties on combustion mechanisms.

[0134] It is also necessary to analyze how these properties affect the combustion process.

[0135] Table 2 summarizes the identified effects, as well as the risks and technical constraints that these characteristics generate.

[0136] [Table 2]

[0137] Bottom ash: Residue from the melting of ash that clogs boilers.

[0138] NOx (Nitrogen oxides): Pollutants contributing to smog and acid rain.

[0139] N2O (Nitrous oxide): Powerful greenhouse gas, impacting global warming.

[0140] SO2 (Sulfur dioxide): Gas causing acid rain and corrosion of installations.

[0141] HCl (Hydrochloric acid): Corrosive product resulting from the combustion of chlorinated biomass.

[0142] Ash valorization: Possible reuse in agriculture (fertilizer) or construction (cement).

[0143] In this vein, an in-depth study was conducted on different sources of lignocellulosic materials in order to assess their suitability as boiler fuels.

[0144] Table 3 summarizes the results obtained in relation to the physico-chemical properties of various lignocellulosic materials, detailing the specific characteristics of the materials tested and their impact on energy and environmental performance e.

[0145] [Table 3]

[0146] Initial analyses of Miscanthus giganteus as a sole source of lignocellulosic material for boiler fuels have revealed its limitations. Its isolated use generates a high ash content, accelerates corrosion, and increases equipment wear.

[0147] Although its low initial moisture content (around 10%) is an advantage, its post-combustion ash content (1 to 5% on a dry basis) remains higher than that of softwoods (1 to 2%) and hardwoods like poplar (0.6 to 4%). This characteristic promotes the accumulation of residues and the deterioration of equipment.

[0148] On the other hand, mixtures with other lignocellulosic materials, with lower ash content and more stable chemical composition, have mitigated these effects, thereby increasing fuel quality and reducing technical constraints.

[0149] 2) Testing different compositions including Miscanthus giganteus and wood

[0150] The moisture content of the samples is measured using an oven. The samples are spread in a 2-3 cm layer on a tray and heated to 105°C for a minimum of 6 a.m. The water content is obtained by the difference in mass between before and after oven drying. The measurements are repeated three times per sample.

[0151] It should be noted that a humidity level exceeding 30% leads to excessive adhesion of the material between the die and the rollers of the compaction system, thus risking damage to the equipment. Furthermore, such a humidity level promotes the growth of filamentous fungi during chip drying, an undesirable phenomenon that is difficult to manage in an industrial environment.

[0152] 3) Selection of the optimal composition and validation of the process

[0153] Experiments were then conducted to evaluate the effectiveness of Miscanthus giganteus when mixed with softwood and hardwood. The objective was to test the viability of a boiler fuel product based on lignocellulosic compositions and to analyze its impact on combustion and fuel quality.

[0154] Indeed, by adjusting the proportions of miscanthus, softwood, and hardwood, it would be possible to optimize fuel performance while meeting energy and environmental requirements. This flexibility would allow the composition to be adapted to available resources and technical constraints. However, the inventors have shown that only mixtures containing between 20% and 50% miscanthus ensure efficient energy recovery and comply with current standards (17225-6:2021). Three compositions proved particularly effective:

[0155] Mixture Ml: 50% miscanthus, 30% hardwoods, 20% softwoods (M50F30R20).

[0156] Mixture M2: 40% miscanthus, 20% hardwoods, 40% softwoods (M40F20R40).

[0157] Mixture M3: 30% miscanthus, 40% hardwoods, 30% softwoods (M30F40R30).

[0158] Thus, the incorporation of Miscanthus giganteus into boiler fuel products has significantly improved moisture control and allowed the maintenance of an acceptable level of (fine) ash, thus demonstrating its value as a component.

[0159] To demonstrate the manufacturing process, a mixture of lignocellulosic materials consisting of 30% Miscanthus giganteus and 70% wood (40% hardwood and 30% softwood), without additives, was used. This mixture and the associated manufacturing process produce a boiler fuel that complies with the quality standards for diameter, length, moisture, and density, as shown in Table 4.

[0160] [Table 4]

[0161] In the following example, we present an example of the process, from the receipt of lignocellulosic materials to their final bagging.

[0162] 4) Example of a method according to the invention

[0163] The steps described in this example follow each other in the following order:

[0164] 1. Sheltering

[0165] 2. Sorting and initial crushing

[0166] 3. Mixture

[0167] 4. High-speed grinding

[0168] 5. Compaction

[0169] 6. Bagging

[0170] Figures 1 and 2 show, respectively, the side cross-sectional view and the top view of an installation designed to apply the process, from step A) of mixing the lignocellulosic materials to bagging. This installation includes:

[0171] - a double-shaft drying mixer (1),

[0172] - three conveyors (2),

[0173] - a high-speed crusher (3),

[0174] - a press (4),

[0175] - an automatic bagging machine (5).

[0176] 4.1. Lignocellulosic materials

[0177] In this example, the lignocellulosic materials tested consisted of 30% Miscanthus giganteus in compressed bundles and 70% wood with 40% (by total mass) hardwood and 30% (by total mass) softwood in the form of wood pieces less than 30 cm long.

[0178] 4.2 Sheltering

[0179] Upon arrival, the lignocellulosic materials had a moisture content of 60%. To protect them from precipitation and reduce their moisture content, they were stored under a ventilated shelter. After four weeks, their moisture content had decreased to 30%.

[0180] 4.3. Sorting and initial crushing

[0181] Once the moisture content was sufficiently reduced, the lignocellulosic materials underwent an initial grinding, which reduced their size to less than 15 cm, thus facilitating their handling.

[0182] The shredded material then passes over a sorting platform to remove unwanted elements (stones, scrap metal, plastic bags).

[0183] 4.4. Mixture of lignocellulosic materials

[0184] This step is carried out by a twin-shaft drying mixer (1) which is illustrated in figures 3 and 4 and described in more detail thereafter.

[0185] This mixer is equipped with a motor (7) that drives the two shafts (6), as well as an integrated drying system (8). Thanks to this configuration, the mixer ensures not only homogenization of the different components, but also controlled pre-drying.

[0186] The cycle duration is set to 10 minutes. An integrated moisture meter provides real-time monitoring of the mixture's moisture content. Thanks to this feature, the drying mixer stabilizes this level at 20%, thus ensuring the efficiency of subsequent process steps.

[0187] Figures 3 and 4 present two perspectives of the same double-axis drying mixer (1): a front view (figure 3) and a top view (figure 4).

[0188] - double axis (6)

[0189] - Engines (7)

[0190] - Drying device (8)

[0191] This industrial equipment, measuring 3,500 mm in length, 1,200 mm in width, and 1,800 mm in height, and weighing 2,000 kg, has a total volume of 1,440 liters (1.44 m³). 3 It can process up to 1,200 kg of material per cycle, depending on the density of the materials.

[0192] Figure d highlights the drying unit (8) and the motors (7) that drive the two mixer shafts: these simultaneously ensure the homogenization and drying of the materials. The mixing mechanism relies on paddles or a double helix, made of stainless steel for wear and corrosion resistance. The rotation speed, between 40 and 50 revolutions per minute, is driven by a 22 kW main motor, assisted by a 2.2 kW auxiliary motor. The unit operates on three-phase power (380 V, 50 / 60 Hz) and consumes approximately 24 kWh. Integrated weighing, metal detection, and IoT connectivity ensure more precise ingredient management, improved traceability, and rapid formulation changes when necessary.

[0193] A programmable logic controller (PLC) manages operating parameters (cycle time, rotation speed, temperature, etc.) and monitors component distribution with an accuracy of approximately ±0.5%. Loading is carried out via a large hopper, while a discharge valve facilitates complete emptying at the end of the cycle, typically set to a duration of 3 to 5 minutes.

[0194] The drying system (8) and the integrated moisture meter allow for precise control of the humidity in the double-shaft drying mixer (1).

[0195] After the mixing and drying cycle, the materials are conveyed to the high-speed crusher (3). They travel along an 8-meter conveyor (2). This conveyor, with a 400 mm wide belt, can transport up to 60 tons of material per hour. The conveyor (2) is equipped with a reinforced rubber belt that resists abrasion and heavy loads, ensuring optimal durability and performance even under heavy loads. It also features a steel frame designed to resist corrosion and minimize vibration, guaranteeing stable and continuous operation. The 4 kW motor, combined with a helical gear reducer, allows for quiet and efficient operation, with a belt speed adjustable between 0.8 and 1.5 m / s to adapt to the specific requirements of the material flow.The integrated 1.5 kW magnetic separator generates a magnetic force of over 1500 Gauss, effectively removing ferrous metals from the conveyed materials. This function prevents damage to downstream equipment, such as the high-speed crusher (3) and press, by eliminating metallic impurities that could cause breakdowns or premature wear.

[0196] 4.5. High-speed grinding - Stage B

[0197] The grinding stage is carried out at high speed, the previously homogenized lignocellulosic mixture being processed by a KAHL brand rotary high-speed mill (3).

[0198] The high-speed mill (3) operates at 5,000 revolutions per minute, a high speed specifically chosen to maintain the temperature of the ground material around 50°C (± 5°C), the optimal condition for subsequent processing. The high-speed mill (3) handles a processing volume of 1,000 kg of material per hour and produces ground material with a particle size of less than 5 mm thanks to a suitable, interchangeable screen.

[0199] Integrated thermocouples continuously measure the temperature of the ground material, allowing automatic adjustments to the rotation speed to stabilize the temperature. In case of temperature fluctuations, the system can modify or interrupt rotation to maintain the ideal conditions required for the process.

[0200] A hygrometer monitors the moisture content of the shredded material, targeting a level of 16% to facilitate optimal compaction in the next stage. The operating time of the high-speed shredder (3) is adjusted in real time according to the hygrometer readings, thus ensuring the homogeneity and quality of the shredded material.

[0201] Figure 5 shows two views (lateral and front) of a high-speed mill (3) specially designed for implementing the process according to the invention.

[0202] - Dust collector (11)

[0203] - Y series engine plate (10)

[0204] - Base (9)

[0205] - Knife (12)

[0206] - Cutting disc (13)

[0207] - Rotating disc (14)

[0208] - Rotor shaft stop (15)

[0209] - Main axis (16)

[0210] - Pulley (17)

[0211] - Drive wheel (18)

[0212] This device, measuring 1200 mm in length, 800 mm in width and 1500 mm in height and weighing 850 kg, rests on a robust base (9) which absorbs vibrations and ensures its stability.

[0213] A Y-series motor plate (10) optimizes torque transmission from the main motor, while a dust collector (11) captures fine particles emitted during grinding, thus limiting material loss and environmental contamination.

[0214] The grinding device includes twelve 25 cm long knives, made of steel containing 12% chromium and with a hardness of approximately 30 HRC. Thanks to this composition, they are highly resistant to wear and impact, ensuring a regular cutting over time. Upstream, a cutting disc (13) fragments the material, then a rotating disc (14) distributes the particles evenly towards the knives (12).

[0215] This configuration is based around the rotor (15), stabilized by a stop that limits vibrations. The main shaft (16) transmits the driving force, while the pulley (17) and, if applicable, a drive wheel (18) convert the motor's energy into grinding force.

[0216] The grinding chamber is made of stainless steel (a carbon steel version is also available) and has an anti-clogging inner lining. The knives (12), arranged on the rotor (15), work together with the discs (13) and (14) to break up the material continuously and homogeneously.

[0217] Once the ground material meets the specifications for particle size, temperature, and moisture, it is conveyed to the press (4), where it is compacted into combustible products ready for use in boilers.

[0218] 4.6. Compaction - Step C: Pressing the ground material to obtain a combustible product for the boiler

[0219] In this step, the shredded material from step B is compressed using a WIESENFIELD WIE-PM-1500 press, capable of producing up to 2,500 kg of fuel per hour. An adjustable router (20) distributes the material flow to the perforated die (23), where the shredded material is compacted into combustion-ready products. The auxiliary drive (22) regulates the compaction pressure, and the protective cover (21) ensures operator safety.

[0220] Inside the press, the temperature can reach up to 130°C, which increases the material's plasticity and promotes the evaporation of residual moisture. To prevent overpressure and control humidity levels, an exhaust fan with a grid removes excess vapor. At the outlet, an oil cooling system (24) lowers the product temperature below 50°C, using a sensor to automatically adjust the cooling power.

[0221] Thanks to this precise control of temperature and humidity, the final fuel has a moisture content of approximately 10%, thus ensuring good stability during storage and high combustion performance.

[0222] After compaction, the boiler fuel product is in the form of cylindrical granules (or "pellets"), measuring 35 mm in length and 6 mm in diameter. Their density reaches 600 kg / m³ 3ensuring easy handling and high calorific value. The blend of lignocellulosic materials includes a minimum of 10% softwood by weight, enhancing the robustness and stability of the pellets during storage and combustion.

[0223] The durability of the resulting pellets was assessed using a durability tester. In this tester, the pellets are rotated in a drum equipped with a deflector before being sieved to isolate and weigh the fine particles. In this case, a durability of 97.5% was achieved, demonstrating excellent abrasion resistance. The pellets thus retain their properties during handling and transport, ensuring optimal performance until combustion.

[0224] Figure 6 shows two views (side and front) of a press specially designed for implementing the process according to the invention.

[0225] - Heat sink (19)

[0226] - Adjustable router (20)

[0227] - Protective cover (21)

[0228] - Auxiliary training (22)

[0229] - Pierced Matrix (23)

[0230] - Oil cooling system (24)

[0231] - Exit (25)

[0232] - Press base with reducer (26)

[0233] - Pebbles (27)

[0234] - Power input (28)

[0235] This press includes an adjustable router (20), a protective cover (21), and an auxiliary drive (22), all of which ensure safe and efficient pressing. The perforated die (23), also called a mold, shapes the boiler fuel products, while the oil cooling systems (24) allow for to maintain an optimal operating temperature. The compacted products are then directed to the outlet (25), where they are collected once the process is complete. The press is securely mounted on a press base with a reduction gear (26), ensuring its stability and facilitating power transfer. Rollers (27) are also integrated to assist the movement and pressing of the materials, thus contributing to the overall efficiency of the system. This configuration makes it possible to obtain high-quality combustible products while preserving the safety and reliability of the process. In this case, this step was carried out with a WIESENFIELD WIE-PM-1500 press. (4) measuring 2600 mm in length, 1300 mm in width, and 2100 mm in height, and weighing approximately 3500 kg. This press is built on a reinforced steel frame that reduces vibration and ensures optimal stability. This press is capable of producing between 1.2 and 1.5 tonnes of product per hour, a capacity that may vary depending on the raw material used and its moisture content.

[0236] The press's main motor is 132 kW, with a 160 kW option for processing harder raw materials. The rotation speed reaches 1450 rpm thanks to an independent 2.2 kW motorized feeder, which controls the material flow to maximize efficiency. The press uses a wear-resistant, 560 mm diameter, 80 mm thick, alloy steel annular die, adjustable to specific requirements. The pellet size is adjustable from 6 mm to 12 mm, with other sizes available upon request. Two rollers ensure uniform pressure during pressing. In terms of compatibility, the press can process various materials such as wood residues (sawdust, chips, bark), agricultural waste (straw, rice husks, corn stalks), animal feed (cereals, flours), and biomass (organic residues).The integrated cooling system prevents overheating during extended production runs, and an automatic lubrication system keeps critical components lubricated to prolong their lifespan. Average power consumption is 145 kWh, with a 380V, 50 / 60Hz three-phase power supply.

[0237] 4.6 Boiler fuel product bagging stage

[0238] Finally, the resulting granules were packaged using an automatic bagging machine. (5), of the Premier Tech Chronos E55 Series type, which incorporates a precise weighing system. Each bag is then hermetically sealed by a secure closure mechanism to ensure the preservation and handling of the products. The bags of boiler fuel products have a standard weight of 15 kg each.

[0239] Additional options include a conditioning device to adjust the humidity and temperature of the raw materials before compaction, a dust collection system to maintain a clean working environment, and infeed and outfeed conveyors to automate the process.

Claims

DEMANDS 1. A process for manufacturing a boiler fuel product comprising the steps of: A) mixing lignocellulosic materials, B) grind the mixture obtained at the end of step A) C) compact the ground material obtained in step B) to obtain a boiler fuel product, where the lignocellulosic materials have a PC proportion by weight (relative to the total weight of the boiler fuel product) of lignocellulosic materials from at least one European and / or tropical / desert sugarcane such that 20 <PC<50 %.

2. The process according to the preceding claim, characterized in that the boiler fuel product is a compacted fuel product selected from the group comprising pellets, logs, briquettes, bundles or blocks.

3. The process according to any one of the preceding claims, characterized in that the compacted mixture of lignocellulosic materials comprises at least wood in a proportion PB by weight (relative to the total weight of the boiler fuel product) such that 20 <PB<80 %, de préférence 30<PB<60 %.

4. The process according to the preceding claim, characterized in that the lignocellulosic materials comprise a PBR proportion by weight of softwood (relative to the total weight of the boiler fuel) of at least 5%, preferably at least 10%, and particularly preferably at least 5. The process according to any one of the preceding claims, characterized in that the ground material at the end of step B) has a temperature between 30°C and 70°C, preferably between 40°C and 60°C.

6. A combustible boiler product that can be obtained by a process according to any one of the preceding claims.

7. A bag of boiler fuel products as defined in the preceding claim.

8. The use of lignocellulosic materials for the manufacture of a boiler fuel, characterized in that said lignocellulosic materials have a PC proportion by weight (relative to the total weight of the boiler fuel) of lignocellulosic materials derived from at least one European and / or tropical / desert sugarcane such as 20 <PC<50 %.

9. The use of a high-speed mill for grinding a mixture of lignocellulosic materials to manufacture a boiler fuel, characterized in that said mixture has a PC proportion by weight (relative to the total weight of the boiler fuel) of lignocellulosic materials from at least one European and / or tropical / desert sugarcane such as 20 <PC<50 %.

10. The use according to claim 9, characterized in that said high-speed crusher has a number of knives greater than or equal to 30, preferably between 30 and 52 knives, of which: - The blade length varies between 21 and 35 cm, preferably between 22 and 30 cm. - the hardness varies between 25 and 35 HRC, preferably between 30 and 35 HRC.

11. The use of a press for compacting the ground material of a mixture of lignocellulosic materials for the purpose of manufacturing a boiler fuel, characterized in that said mixture has a PC proportion by weight (relative to the total weight of the boiler fuel) of lignocellulosic materials derived from at least one European and / or tropical / desert sugarcane such as 20 <PC<50 %.

12. The use according to the preceding claim, characterized in that said press comprises, in addition to iii) at least one means for compacting the crushed material and iv) at least one means for evacuating water vapor: i) at least one means for measuring moisture (allowing the moisture content of the crushed material to be determined, e.g., a moisture meter) and ii) at least one control system coupled to at least one means for compacting the crushed material, at least one means for evacuating water vapor, and at least one means for measuring moisture, which control system determines the activation or deactivation of iii) at least one means for compacting the crushed material and iv) at least one means for evacuating water vapor, so that the boiler fuel products have the desired moisture content.

13. The use according to the preceding claim, characterized in that the press comprises at least one rotor, with at least two rollers and a die having a plurality of holes, preferably said at least one rotor is equipped with specific blades and / or vanes.

14. The use according to the preceding claim, characterized in that said at least one rotor rotates at a speed of 200 to 800 revolutions per minute, preferably at a speed of 300 to 700 revolutions per minute.

15. The use according to claim 13, characterized in that the die is designed to be interchangeable and has holes with a diameter ranging from 2 mm to 30 mm, preferably from 4 mm to 25 mm.

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