Method for producing biofuel pellets by low pressure steam and physical waste treatment

Abstract

This disclosure discloses a method for enhancing the production of biofuel pellets from waste biomass by utilizing a novel energy transfer mechanism in process water. The method simultaneously induces rotational and vibrational energy within water clusters, thereby synergistically enhancing ion transport and extraction within the biomass. This enhanced migration facilitates the removal of mineral ions, thereby increasing the relative carbon content of the biomass. Subsequent low-pressure steam purging allows for the rearrangement of biomass fibers, resulting in bioparticles with a higher calorific value. Due to the low-pressure steam purging step, this sequential process enables a sustainable fuel production method with a low carbon footprint.

Description

Technical Field

[0001] This invention relates to a method for converting agricultural waste biomass into bio pellet fuel, and more specifically, to a process for producing high-energy-value biosolids suitable for use as renewable fuel by using physical treatment methods combined with low-steam-pressure purging. Background Technology

[0002] In an era where rapid industrialization and economic development have led to the dwindling global fossil fuel reserves, there has been a constant effort to find renewable energy sources. The International Energy Agency estimates that renewable energy must account for a significantly larger share of global energy consumption to achieve climate goals and ensure energy security. Among various renewable energy options, biomass energy has unique advantages, particularly in utilizing existing waste streams that would otherwise cause environmental pollution. Converting various agricultural waste biomass provides a feasible and economical method for achieving circular economy goals, especially suitable for many agricultural countries that can use these biosolids as fuel.

[0003] Agricultural residues—including rice husks, wheat straw, corn stalks, bagasse, palm kernel shells, and coconut shells—represent millions of tons of underutilized organic matter each year. These materials, if left untreated, often present disposal difficulties and exacerbate air pollution due to the common practice of open burning in many areas.

[0004] Various thermochemical conversion technologies have been developed to convert biomass into high-energy-density fuels. These technologies include mild pyrolysis, hot water carbonization, steam explosion pretreatment, and pressurized pyrolysis. In many of these biomass conversion processes, high steam pressure has been explored as a means to enhance biomass decomposition, remove volatile compounds, increase carbon content, and improve fuel performance. However, the use of high steam pressures—typically above 20 bar, and often around 30 bar—is not uncommon in such experimental plant facilities. Some advanced processes even operate at pressures of 40 to 50 bar, corresponding to temperatures between 250°C and 300°C. While these conditions can effectively alter the structure and chemical properties of biomass, significant practical and economic barriers remain for their widespread commercial application.

[0005] Process installations requiring high pressure and temperatures exceeding 250°C have substantial capital costs. Pressure vessels, reactors, and related equipment must be manufactured using specialized materials capable of withstanding both thermal and mechanical stresses. The need for thick-walled vessels, high-grade steel or alloy structures, complex sealing systems, and robust safety mechanisms significantly increases initial investment costs. Furthermore, substantial expenditures are required for risk mitigation measures, including specialized equipment and skilled personnel. High-pressure operation demands comprehensive safety protocols, regular inspection and maintenance plans, specially trained and certified operators, emergency response systems, and compliance with stringent regulatory requirements. Insurance costs for high-pressure facilities are significantly higher, and the potential consequences of equipment failure—including catastrophic pressure vessel rupture—necessitate extensive preventative measures.

[0006] Furthermore, high-pressure systems typically involve higher operational complexity, increased energy consumption to achieve and maintain process conditions, longer heating and cooling cycles leading to reduced capacity, greater maintenance downtime, and limited scalability for small to medium-sized operations. These factors collectively limit the accessibility of such technologies, particularly in developing regions where agricultural waste biomass is most abundant but where financial and technological resources are limited.

[0007] A key challenge in biomass fuel production is the inherently high moisture content of agricultural residues, which typically ranges from 30% to 60% of their weight, depending on the source and storage conditions. High moisture content significantly reduces the calorific value of biomass fuels, leading to decreased combustion efficiency, difficulties in handling and storage due to biodegradation, and limited transport economics due to increased weight. Traditional drying methods—such as sun drying, hot air drying, or drum drying—are either time-consuming, weather-dependent, and energy-intensive, or result in uneven moisture distribution. While high-pressure steam treatment can effectively reduce moisture through intense heat treatment, it reintroduces the aforementioned economic and safety issues.

[0008] Therefore, a sustainable low-steam-pressure process is needed to produce high-energy-value biosolids that can be used as fuel. Ideally, this process should effectively remove moisture and densify biomass, operate at pressures below 10 bar to reduce equipment costs and safety requirements, employ physical processing methods that avoid chemical additives, maintain a favorable energy input-output ratio for high energy efficiency, support modular and scalable implementations suitable for distributed processing near biomass sources, and produce high-quality bio pellets with consistent combustion performance and uniform quality. Furthermore, the ideal process should use steam or hot water as the processing medium, enabling it to simultaneously serve as a heat transfer medium, a physical processing catalyst, and a purging medium for removing volatiles and reducing moisture content. The integration of physical methods such as mechanical pressing, controlled steam purging at medium pressure, thermal conditioning, and pelleting promises to achieve these goals without incurring the high costs and operational complexities of high-pressure systems.

[0009] US Patent No. 10,858,607 B2, entitled "Biomass Upgrading and Cleaning Process," describes a process for removing entrained salts and light volatiles by pre-washing biomass followed by steam explosion, using high-pressure steam explosion (typically above 20 bar) followed by rapid decompression. This patent also uses a secondary wash after steam explosion to remove additional salts, and employs mechanical dehydration and evaporative drying, with the aim of producing biomass suitable for pelleting or use as a solid fuel. This patent addresses a similar goal of removing mineral contaminants from biomass and preparing it for pellet production. However, this invention differs significantly from it, employing low-pressure pulsed steam treatment (below 16 bar, typically 7 to 14 bar) instead of high-pressure steam explosion (above 20 bar); and employing wet plasma and microbubble technology for ion extraction instead of conventional washing. This invention also introduces fuzzy logic control to control the pulsed steam treatment at a frequency of 10 to 50 Hz and includes electromagnetic activation of supplemental lignin to enhance binding.

[0010] US Patent No. 8,961,628 B2, entitled "Pretreatment of Biomass Using a Steam Explosion Method," describes a steam explosion pretreatment of biomass prior to gasification or pelletizing using high-pressure steam (at least 14 times atmospheric pressure, or approximately 14+ bar), including a hot water heating stage, followed by a steam explosion stage, and a mechanical refining stage to agitate the pressurized biomass, generating fine biomass pellets through rapid decompression, and feeding the pellets directly into a gasifier or pellet mill. This patent covers steam pretreatment of biomass before various subsequent processes. The present invention differs in its operating pressure range: it employs significantly lower pressures (below 16 bar, compared to approximately 14+ bar in this patent); it uses pulsed steam application controlled by fuzzy logic, rather than continuous steam exposure; it integrates ion extraction pretreatment utilizing wet plasma and microbubbles; it uses pulses controlled at specific frequencies of 10 to 50 Hz to achieve fiber rearrangement; and it employs a multi-stage processing scheme including constant pressure holding and rapid decompression stages.

[0011] US Patent No. 10,933,427 B2, entitled "Method and Apparatus for Biomass Preparation," describes the preparation of lignocellulose biomass through water extraction and selective particle size optimization. It involves centrifuging the biomass, followed by abrasive grinding and drying, focusing on the removal of water-soluble compounds and mechanical processing. This method is suitable for subsequent mild pyrolysis, carbonization, or pellet production, but does not employ steam treatment. This patent relates to the preparation of biomass for pelletization using physical and mechanical methods. This invention differs significantly from that patent because it uses wet plasma and microbubbles for ion extraction instead of simple water extraction; it incorporates low-pressure pulsed steam treatment not found in the patent; it employs electromagnetic activation of the lignin binder; it removes mineral ions by activating water with plasma rather than mechanical separation; and it targets the extraction of specific ions such as potassium, sodium, and chloride to improve combustion quality.

[0012] European Patent No. EP 2,473,585 A1, entitled "Method and System for Producing Pellets from Biomass in a Pellet Press," describes an energy-efficient pellet production method that uses hot air to maintain the temperature of the biomass (above 65°C) between a dryer and a pellet press. The focus is on thermal energy management throughout the production process, employing a hot steam dryer or drum dryer to dry the biomass. It does not include specific pretreatment for ion removal or steam explosion, and its goal is to reduce energy consumption by maintaining the biomass temperature. This patent focuses on energy efficiency in biomass pellet production. This invention differs substantially because it incorporates a pretreatment stage using wet plasma technology for ion extraction; employs low-pressure pulsed steam treatment to alter the biomass structure; uses electromagnetic wave activation to supplement lignin; focuses on improving fuel quality through ion removal rather than primarily on energy efficiency; and achieves fiber rearrangement through controlled pulsed steam circulation.

[0013] This invention distinguishes itself from existing technologies through several novel features: wet plasma and microbubble ion extraction, which uses plasma to activate water combined with microbubbles for efficient extraction of mineral ions—a feature absent in traditional washing methods; low-pressure pulsed steam treatment, operating at pressures below 16 bar (compared to 20 to 50 bar in existing technologies), and generating a pulsed steam flow at frequencies of 10 to 50 Hz through intelligent fuzzy logic control; a multi-stage steam treatment scheme, combining pulsed purging, constant pressure maintenance, and rapid decompression to achieve carbon chain rearrangement; electromagnetic lignin activation, innovatively using low-frequency electromagnetic waves (10 kHz to 10 MHz) and ferrite coil inductors to activate and replenish lignin binders; an integrated process system, integrating ion extraction, low-pressure steam treatment, electromagnetic activation, and granulation into a coordinated system to produce higher-quality biogranules with lower capital and operating costs; and agricultural nutrient recovery, recovering mineral ions from washing water as valuable agricultural nutrients, thereby bringing circular economy benefits.

[0014] These innovations collectively enable the production of high-quality biomass pellets (calorific value 18 to 21 MJ / kg, density 650 to 800 kg / m³) with significantly lower pressure, cost, and risk, offering clear advantages over traditional high-pressure steam explosion processes.

[0015] To date, no commercially viable process has successfully combined low-pressure steam treatment with physical processing methods to produce bio pellet fuel that meets quality standards for industrial and residential combustion applications while remaining economically affordable for agricultural communities and small-scale energy producers. This invention addresses these shortcomings by providing an innovative biomass conversion method that utilizes process water treatment and low-pressure steam purging to generate high-quality bio pellet fuel from waste biomass materials. Summary of the Invention

[0016] This invention provides a novel process for converting agricultural waste biomass into high-quality biomass pellet fuel through a physical processing method operating at low steam pressure. Unlike traditional high-pressure systems requiring significant capital investment in equipment and extensive safety measures, this invention achieves comparable or even superior fuel performance at steam pressures significantly below 20 bar, thereby reducing capital and operating costs while maintaining process safety and efficiency. The biomass includes bagasse, giant reed grass, lemongrass, oil palm branches, fibrous fruit plant stems, and other biomass materials such as sawdust.

[0017] The physical method of this invention utilizes a unique energy transfer mechanism, low-pressure steam purging, and a pelletizing device to process waste biomass containing more than 20% fiber by weight into biomass pellet fuel with higher calorific value. This process is particularly suitable for fibrous agricultural residues, including but not limited to bagasse, rice straw, wheat straw, corn stalks, and other cellulosic materials commonly used in agricultural production.

[0018] This production process focuses on sensitizing biomass during the bagasse stage through controlled low-pressure steam purging and metal ion removal, followed by pelleting, to achieve continuous and sustainable production of high-calorific-value biomass pellet solid fuel. The removal of metal ions, especially alkali and alkaline earth metals that can cause slagging and fouling during combustion, further improves the fuel quality and combustion performance of the resulting biomass pellets.

[0019] This invention represents a truly renewable energy solution because its biomass feedstock comes from fast-growing agricultural resources that can undergo multiple growth cycles per year. This contrasts sharply with fossil-based carbon sources, which are non-renewable resources that require billions of years of geological processes to form. By making high-value use of agricultural waste that might otherwise be openly burned or left to decompose, this process not only aligns with circular economy principles but also provides a sustainable alternative to coal and other fossil fuels.

[0020] A key innovation of this invention lies in the use of a fuzzy logic controller and related control devices to implement controlled low-pressure steam purging. By introducing an intelligent control algorithm, pulsed steam flows are applied to bagasse or other fibrous biomass materials. This pulsation induces a greater degree of rearrangement of cellulose fibers and advantageously alters the fiber structure at the molecular and microscopic levels, thereby achieving higher solids density and superior binding properties in the subsequent pelleting process.

[0021] The structural changes achieved through pulsed steam treatment can significantly improve the calorific value of biomass after steam treatment by increasing carbon concentration, reducing oxygen content through partial dehydration reaction, removing volatile compounds that contribute little to calorific value, and forming a more uniform, denser, and more efficient material structure.

[0022] It is noteworthy that the pulsed dynamics and thermal effects achieved by this invention through a controlled low-pressure steam purging method can achieve the same solid density, structural modification effect, and fuel quality as traditional 20-30 bar high-pressure steam treatment without incurring the capital costs, operational risks, and technical complexity associated with it. This breakthrough makes biomass fuel production at different scales, from small-scale farm operations to industrial facilities, economically feasible, thereby making advanced biomass conversion technologies more widely available.

[0023] Therefore, the primary objective of this invention is to provide a method for producing biomass pellet fuel from agricultural waste using low-pressure steam treatment.

[0024] A further objective of this invention is to provide a biomass conversion process that can achieve high fuel quality and high density without the need for high-pressure equipment and related safety measures.

[0025] Another objective of this invention is to provide an intelligent control system utilizing fuzzy logic to optimize pulsed steam purging, thereby enhancing the biomass structure modification effect.

[0026] Another objective of this invention is to provide a sustainable and economically accessible process for converting renewable agricultural waste into high-calorific-value solid fuels suitable for industrial and residential combustion applications.

[0027] These and other objects, features and advantages of the present invention will become more apparent from the following detailed description of preferred embodiments and the accompanying drawings. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of a bioparticle fuel production system according to a preferred embodiment of the present invention.

[0029] Figure 2 The operation and structure of the mineral ion extraction tank system are shown in more detail. This system constitutes a key pretreatment stage in the bioparticle fuel production process of this invention.

[0030] Figure 3 The low-pressure steam purge chamber (31) and its associated steam generation and control system are shown in detail, representing a key and innovative operational phase of the present invention.

[0031] Figure 4The final processing stage of the bio-pellet fuel production system according to the present invention is shown, including moisture reduction, lignin addition and electromagnetic activation, pelleting and product collection.

[0032] Figure 5 Another embodiment of the bioparticle fuel production method according to the present invention is shown, wherein the process flow is simplified by eliminating the low-pressure steam purging stage while retaining the beneficial mineral ion extraction pretreatment. Detailed Implementation

[0033] The following detailed description illustrates the best mode contemplated for carrying out exemplary embodiments of the present invention. This description should not be considered limiting, but merely illustrative of the general principles of the invention, the scope of which should be determined by the appended claims.

[0034] Now refer to Figure 1 The diagram illustrates a bio-pellet fuel production system according to a preferred embodiment of the present invention. The system integrates multiple processing stages in a continuous flow configuration, including feedstock preparation and conveying, mineral ion extraction, low-pressure steam purging, dehumidification, pelletizing, and product collection. The entire process is coordinated and controlled by a main programmable logic controller (PLC) (61) to ensure optimal sequence, timing, and parameter control among the various operating units.

[0035] Biomass feedstock can consist of bagasse, rice straw, wheat straw, corn stalks, or other fibrous agricultural residues, which are first pre-cut or mechanically pulverized to form uniform dimensions of approximately 10 to 15 millimeters in length. This size reduction step has multiple benefits: it increases the surface area available for subsequent chemical and physical processing, ensures uniform processing of the entire biomass mass, facilitates efficient handling and transport in processing equipment, and promotes uniform steam penetration during the purging stage.

[0036] The prepared biomass feedstock is fed into the mineral ion extraction tank (21) via a continuous feed system (11). This continuous feeding arrangement enables uninterrupted processing while maintaining consistent product quality and maximizing processing efficiency. The feed rate into the mineral ion extraction tank (21) is controllable and can be adjusted according to the moisture content of the incoming feedstock, the required ion extraction residence time, and the overall system capacity requirements.

[0037] Within the mineral ion extraction tank (21), the biomass undergoes a critical pretreatment step to remove alkali metals, alkaline earth metals, and other mineral ions naturally present in agricultural biomass. These ions include potassium, sodium, calcium, magnesium, chlorine, and sulfur compounds, which can cause problems in combustion applications, such as ash slagging, furnace scaling, combustion equipment corrosion, and reduced combustion efficiency.

[0038] The ion extraction process employs a wet plasma and microbubble system, achieving ion extraction through activated wash water in a mineral ion extraction tank (21). The energy driving this extraction process is provided by a wet plasma and microbubble generator (22), which creates an activated water environment through plasma discharge and the simultaneous generation of tiny bubbles. The plasma discharge generates reactive species, localized heating, and electrochemical effects, thereby enhancing the mobility of ions and their ability to dissolve from the biomass structure. Microbubbles increase the interfacial contact area between the wash water and the biomass surface, providing mechanical agitation at the microscale to remove minerals adhering to the surface and promoting the mass transfer of dissolved ions from the biomass to the bulk liquid phase.

[0039] During the soaking process, the biomass feedstock is placed in a water-permeable mesh bag or basket structure, allowing the activation wash water to circulate freely while containing the biomass material and preventing the loss of fine particles. This structure ensures that all biomass material is in uniform contact with the ion extraction medium. The residence time in the mineral ion extraction tank (21) is typically controlled within the range of 15 to 60 minutes, depending on the initial mineral content of the feedstock, the required degree of demineralization, and the activity level of the wet plasma and microbubble system.

[0040] After the specified processing time is completed, the mesh bag containing the processed biomass is mechanically lifted out of the mineral ion extraction tank (21) and transferred to a transition station where excess water can be drained. This transition station can be equipped with a gentle mechanical press or vibration device to promote dehydration without damaging the biomass fiber structure. Subsequently, the ion-extracted biomass is transported to a low-pressure steam purge chamber (31) for the next critical processing stage.

[0041] The low-pressure steam purge chamber (31) is a key innovative component of this invention. Unlike traditional steam treatment systems that operate under constant high pressure, this system applies pulsed steam treatment under low pressure conditions and is controlled by a fuzzy logic controller integrated in the main PLC (61).

[0042] Steam is delivered from the boiler (32) to the purge chamber (31), producing saturated steam or slightly superheated steam at a pressure below 10 bar, preferably in the range of 3 to 8 bar. At this pressure level, the corresponding steam temperature is approximately 133°C to 170°C, which is sufficient to induce beneficial structural and chemical changes in biomass without the need for expensive pressure vessels and safety systems associated with high-pressure operation.

[0043] The fuzzy logic controller implements an intelligent control algorithm to adjust the steam flow rate, thereby forming a pulsating pressure and temperature curve in the purge chamber (31). The controller does not maintain constant steam conditions, but alternates between the active steam injection phase and the steam flow rate reduction or cessation phase, thus generating a pulse effect. The pulse frequency, pulse duration, flow intensity during the active steam phase, and overall cycle characteristics are all dynamically adjusted based on feedback from temperature, pressure, moisture content, and processing time sensors.

[0044] This pulsed processing method offers several advantages over traditional constant-pressure steam treatment. Alternating pressure and temperature cycles induce mechanical stress within the biomass fiber structure, creating microcracks and promoting structural rearrangement. Cellulose fibers achieve greater rearrangement and compaction due to repeated expansion and contraction cycles. Hemicellulose and lignin components undergo partial hydrolysis and redistribution, improving their role as natural binders in subsequent pelleting. Through pressure cycling, volatile compounds and residual moisture are more effectively removed from the biomass.

[0045] The structural changes that occur during the pulsating steam purging process can significantly improve the calorific value of the steam-treated biomass through a variety of mechanisms, including partial dehydration to increase the carbon-oxygen ratio, removal of low-energy volatile compounds, densification to increase the energy content per unit volume, and improved combustion performance due to improved fiber structure and uniformity.

[0046] It is worth noting that the combination of low-pressure operation and pulsed control enables this system to achieve comparable solid density and fuel properties without incurring the capital costs, operational complexity, safety risks, and energy losses associated with traditional 20-30 bar high-pressure steam processing systems. This represents a significant technological and economic breakthrough in biomass fuel production technology.

[0047] During steam purging in the purging chamber (31), condensate is formed naturally when the steam comes into contact with the cooler biomass and transfers heat. The condensate contains water-soluble compounds, volatile organic compounds and residual mineral ions extracted from the biomass, and is collected from the bottom of the steam purging chamber (31) and introduced into the ion separation chamber (23).

[0048] In the ion separation chamber (23), the condensate is treated to remove dissolved solids, mineral salts, and organic compounds. The treatment process may employ one or more of the following methods: concentration of dissolved solids by evaporation, precipitation separation by adjusting pH or adding a precipitant, removal of particulate matter and dissolved ions by filtration or membrane separation, and selective removal of specific ionic species by ion exchange or adsorption processes.

[0049] The treated condensate is now largely purified and has a significantly reduced mineral content. It is then recycled and returned to the mineral ion extraction tank (21) for reuse in the ion extraction stage. This water recycling method has significant advantages, including reduced fresh water consumption, reduced wastewater discharge, recycling and reuse of activated water generated by the wet plasma system, and improved sustainability and economy of the entire process.

[0050] The ionic salts and concentrated mineral compounds removed and collected during the ion separation chamber (23) process are stored in a dedicated collection tank (24). These recovered minerals can be used as agricultural fertilizers, soil conditioners, or industrial chemicals, thus creating additional revenue streams and further enhancing the circular economy characteristics of the process.

[0051] After low-pressure steam purging, the biosolids typically retain a high moisture content, usually 30% to 50% by weight, depending on the initial moisture content of the raw material, the intensity of the steam treatment, and the degree of mechanical dehydration during the transition phase. To make the material suitable for efficient pelleting and to ensure that the final bio pellet fuel meets the moisture content specifications, the steam-treated biosolids are sent to a hot air drying unit (41).

[0052] The hot air drying unit (41) applies heated air, typically in the range of 80°C to 150°C, to the biomass material. The heated air can be generated by producing biomass pellets through combustion, by heat exchange with exhaust gas from a boiler (32), or by a dedicated heating element driven by electricity or other energy sources. The hot air drying unit (41) can be configured as a drum dryer, a belt dryer, a fluidized bed dryer, or other suitable drying equipment known in the art.

[0053] The goal of the drying process is to reduce the moisture content of the steam-treated biosolids to a target range of 7% to 14% by weight. This moisture content range is ideal for several reasons: it is low enough to ensure good pelleting performance, as excessive moisture hinders agglomeration and pellet formation; it allows the finished bio-pellets to have a high calorific value, as moisture directly reduces the net calorific value of the fuel; it ensures storage stability, preventing biodegradation, mold growth, and self-heating during storage; and it is still high enough to promote pelleting agglomeration, as a certain amount of moisture acts as a lubricant and helps activate the binding properties of natural lignin during pelleting.

[0054] The temperature, airflow rate and residence time in the drying unit (41) are controlled by the main PLC (61) to achieve the target moisture content stably while minimizing energy consumption and to prevent over-drying or biomass thermal degradation.

[0055] The dried biosolids have now reached their optimal moisture content and are conveyed to a biogranulator (51), where they undergo mechanical compression and extrusion to form dense and uniform granules. The biogranulator (51) typically includes a pellet die with cylindrical orifices of a predetermined aperture (typically 6 to 8 mm for standard biogranules), a rotating pressure roller that presses the biomass material against the die and forces it through the orifices, a cutting mechanism that cuts the granules to a controlled length as they emerge from the die, and a drive system that provides the mechanical power required for compression.

[0056] During pelleting, biomass materials are subjected to high localized pressure and shear forces. The combined effects of pressure, frictional heat, and the natural adhesive properties of partially softened lignin cause the individual biomass pellets to bind together, forming coherent and mechanically stable granules. The structural modification induced by the previous low-pressure steam purging stage, especially the rearrangement of cellulose fibers and the redistribution of lignin, significantly enhances the pelleting process, resulting in pellets with superior density, durability, and mechanical strength compared to pellets made from untreated biomass.

[0057] Bio pellets produced by the bio pellet mill (51) have several desirable properties, including a high bulk density of typically 600 to 750 kg / m³, a uniform cylindrical shape that facilitates automatic handling and feeding, a high calorific value of typically 16 to 19 MJ / kg (dry basis), low ash content due to prior mineral extraction, and excellent combustion characteristics with lower emissions and less slagging. They also have good storage stability and are resistant to moisture absorption and biodegradation.

[0058] The final bio-particles produced by the bio-pelletizer (51) are discharged and collected in a collection chamber (12), which may be designed as a hopper, storage bin, or conveyor system leading to packaging equipment. The bio-particles typically undergo a brief cooling phase after leaving the pelletizer to reduce their temperature and complete final hardening before packaging.

[0059] Starting from the collection chamber (12), the bioparticles will enter the packaging operation, where they can be packed into consumer small packages (typically 10 to 20 kg / bag for residential use), into large bags or ton bags (typically 500 to 1000 kg for commercial applications), or stored in bulk silos for large-scale industrial fuel use.

[0060] Throughout the production process, the main programmable logic controller (PLC 61) is responsible for coordinating all transfer sequences, monitoring process parameters, adjusting operating conditions to maintain product quality and process efficiency, executing safety interlocks and emergency shutdown procedures, and recording operating data for quality control and process optimization.

[0061] The system also integrates multiple utility systems to support each processing stage. The boiler (32) provides the necessary steam for the low-pressure purging operation in the purging chamber (31). The boiler (32) can achieve partial or complete energy self-sufficiency by burning part of the biomass particles, or it can use other fuel sources including natural gas, oil, or coal.

[0062] The feedwater tank (33) supplies water to multiple locations in the system, including makeup water for the boiler (32), fresh water for the mineral ion extraction tank (21) to compensate for evaporation losses and product moisture losses, and process water for cleaning and auxiliary operations. The water from the feedwater tank (33) can be treated to remove hardness and dissolved solids before being sent to the boiler to prevent scaling and corrosion.

[0063] By returning the water recovered from the ion separation chamber (23) to the mineral ion extraction tank (21) and combining it with the recovery of condensate from the steam purging operation, the overall fresh water consumption can be minimized and the environmental footprint of the production process can be reduced.

[0064] Figure 2 The operation and structure of the mineral ion extraction tank system are shown in more detail. This system constitutes a key pretreatment stage in the biomass pellet fuel production process of this invention. This ion extraction system is designed to remove alkali metals, alkaline earth metals, chlorine, sulfur, and other mineral contaminants from biomass feedstock before steam treatment and pelleting. The system integrates advanced wet plasma technology, microbubble aeration, and intelligent water circulation to achieve efficient demineralization while maintaining process efficiency and minimizing water consumption.

[0065] Under the coordination of the plant’s main programmable logic controller (PLC 61), the transfer sequence of the pre-cut biomass during the ion extraction process is precisely controlled. The pre-cut biomass has been mechanically crushed into a uniform size of about 10 to 15 mm in the pre-preparation stage and then conveyed from the feed point (11) and loaded into the basket (27).

[0066] The wire basket (27) is made of corrosion-resistant materials, such as stainless steel wire mesh, polymer mesh, or other permeable materials capable of withstanding the chemical and physical conditions within the treatment tank. The mesh size of the basket is selected to retain biomass pellets while allowing treatment water to flow freely within the biomass stack. Typically, the mesh opening ranges from 2 mm to 5 mm, effectively accommodating pre-cut biomass while providing sufficient permeability.

[0067] The basket (27) is equipped with a suitable lifting mechanism, such as a suspended lifting system, a winch assembly, or an automated transfer robot arm, to lower and lift the basket into the mineral ion extraction tank (21) in a controlled manner. The basket capacity is designed to accommodate batch sizes suitable for the overall system throughput, typically 100 kg to 1000 kg of biomass per batch, depending on the scale of the production facility.

[0068] After being loaded with pre-cut biomass, the basket (27) is mechanically lowered and completely submerged in the mineral ion extraction tank (21), where the biomass undergoes enhanced treatment under the combined action of wet plasma activation and microbubble agitation. The mineral ion extraction tank (21) is made of chemically resistant materials, such as stainless steel, fiber-reinforced polymer composites, or lined with concrete, to withstand the corrosive effects of dissolved minerals and the electrochemical environment caused by plasma discharge.

[0069] The mineral ion extraction tank (21) contains sufficient washing water to completely submerge the mesh basket (27) and provides an appropriate liquid-to-solid ratio for efficient ion extraction. The liquid-to-biomass weight ratio is typically maintained in the range of 5:1 to 15:1 to ensure sufficient water to dissolve the extracted ions without over-diluting them.

[0070] The ion extraction process is driven by a wet plasma and microbubble generator (22), which generates plasma discharge and fine air bubbles simultaneously in an aqueous environment to enhance mass transfer and agitation. When the main PLC (61) sends a control signal to the generator (22), electrical energy is delivered to a dedicated plasma emitter (28) located in or around the extraction tank (21).

[0071] The plasma emitter (28) is a novel component of the invention, made of a specially designed multi-oxide composite material to provide optimal energy transfer and withstand the harsh electrochemical environment of plasma discharge in aqueous solution. The multi-oxide composite material may contain one or more metal oxides, including titanium dioxide (TiO2), zirconium dioxide (ZrO2), alumina (Al2O3), or other ceramic oxides known for their electrical properties and chemical stability.

[0072] The multi-oxide composite structure offers several functional advantages. It has high dielectric strength, enabling safe operation at the voltage required to generate plasma; it exhibits excellent corrosion resistance in the ionized water environment of the treatment tank; it has sufficient thermal stability to withstand localized heating during plasma discharge; and it can efficiently convert electrical input energy into the energy required for plasma formation.

[0073] After being powered on, the plasma emitter (28) generates localized plasma regions in the washing water. The plasma discharge produces a variety of beneficial effects, including generating reactive oxygen species (hydroxyl radicals, hydrogen peroxide, ozone) that facilitate ion dissolution, generating ultraviolet radiation that helps break the bonds between minerals and biomass, forming localized heating zones that enhance ion mobility, and establishing an electrochemical potential gradient that drives ions to migrate from the biomass surface to the bulk liquid phase.

[0074] Simultaneously with plasma activation, microbubbles are released into the extraction tank (21) via one or more air diffusers (29) located near the bottom or sidewall of the tank. The air diffusers (29) are designed to produce tiny bubbles, typically ranging from 10 micrometers to 500 micrometers in diameter, much smaller than the bubbles produced by conventional aeration systems.

[0075] Microbubbles play multiple roles in the ion extraction process. They provide gentle yet thorough agitation throughout the treatment tank, ensuring uniform contact of the activated wash water with all biomass surfaces; increase the gas-liquid interface area, enhancing oxygen transfer into the solution and thus aiding the oxidation reaction; create upwelling within the tank, promoting circulation and preventing stagnation zones; and through the mechanical action of bubble formation and collapse, they help to strip mineral particles and dissolved ions from the biomass surface.

[0076] The wet plasma activation implemented by the emitter (28) combined with the microbubbles generated by the diffuser (29) creates a synergistic effect, achieving superior ion extraction efficiency compared to using either technique alone. The plasma provides chemical and electrochemical activation, while the bubbles ensure sufficient physical contact and mass transfer in the biomass-water system.

[0077] To maintain treatment efficiency and reduce fresh water consumption, wash water is transported through appropriate piping and pumping systems (not shown in detail in the diagram, but by...). Figure 2 (Implied by the flow arrows in the diagram) ions continuously circulate between the ion extraction tank (21) and the ion separation tank (23). This circulation serves multiple purposes, including removing extracted ions from the treatment tank to prevent their redeposition onto the biomass, maintaining suitable ionic strength and pH conditions for continuous ion extraction, and integrating recycled water from other process stages.

[0078] It is worth noting that, as in Figure 1 As described in the related description, the condensate recovered from the low-pressure steam purge chamber (31) is also added to the washing water circulation stream flowing through the extraction tank (21). This integration of steam condensate brings several benefits, including reducing the need for fresh make-up water, recovering the heat energy contained in the warm condensate, and utilizing the residual ion content in the condensate to maintain a suitable solution chemistry environment in the treatment tank.

[0079] The ion separation tank (23) receives mineralized wash water from the extraction tank (21) and removes dissolved and suspended mineral salts using one or more separation processes. The separation processes may include chemical precipitation by adjusting the pH, adding a precipitant or electrochemical deposition, physical filtration by a membrane system, cartridge filter or sand filter, crystallization of dissolved salts by evaporation concentration, and ion exchange or adsorption using a selective resin bed or active medium.

[0080] The separated and concentrated ionic salts, which may include potassium chloride, potassium carbonate, calcium salts, magnesium salts, and other mineral compounds extracted from biomass, will be collected from the ion separation tank (23) and transported to the ion solids storage tank (24). These recovered mineral salts can be commercially valuable as fertilizer components, chemical feedstocks, or soil amendments, thus forming a second source of revenue and enhancing the overall economics of the bioparticle production process.

[0081] The wash water, after being treated to remove a significant amount of minerals, is returned from the ion separation tank (23) to the extraction tank (21) for continued circulation. Fresh makeup water from the water supply tank (33) is added as needed to compensate for water losses caused by evaporation, product moisture content, and system discharge.

[0082] After the specified processing time in the mineral ion extraction tank (21) is completed, typically 15 to 60 minutes, depending on the type of raw material and the required degree of demineralization, the PLC (61) will initiate the basket lifting procedure. The basket (27) containing the demineralized biomass is mechanically lifted out of the extraction tank (21) and remains above the tank for initial drainage by gravity.

[0083] Subsequently, the basket (27) is transferred to the transfer station (26), which serves as an intermediate processing point between the ion extraction stage and the subsequent steam purging stage. At the transfer station (26), the treated biomass undergoes several operations in preparation for steam treatment.

[0084] First, the biomass is transferred from the wire basket (27) to a smaller transport basket or tray to be suitable for delivery into the low-pressure steam purging chamber (31). This transfer can be done manually or by an automated tipping and conveying mechanism.

[0085] Secondly, most of the moisture associated with the biomass is removed or eliminated mechanically at the transfer station (26). This dehydration process can be carried out by one or more of the following methods: free drainage by gravity on a perforated screen or mesh; gentle mechanical pressing using rollers, plates or screw propellers to squeeze out excess water without crushing the fibers; vacuum drainage by applying negative pressure; and promoting water separation and discharge by vibration or agitation.

[0086] The goal of the dehydration process is to reduce the moisture content of the biomass to a level suitable for subsequent steam purging, typically 40% to 60% by weight. This moisture level represents a balance: it is low enough to avoid introducing too much moisture into the steam chamber, which would lower the steam temperature and increase condensate formation; but at the same time, it is high enough to maintain fiber flexibility and prevent the biomass from becoming brittle or the fibers from breaking.

[0087] The removed water is returned from the transfer station (26) to the extraction tank (21) or directed to the recycling system to further improve water recycling efficiency.

[0088] Once the processed and partially dehydrated biomass has been correctly loaded into smaller transport baskets at the transfer station (26), the PLC (61) coordinates the next transfer sequence. The transport baskets can be conveyed to the low-pressure steam purging chamber (31) via manual or automated material handling systems, where the biomass will undergo further processing. Figure 1 The aforementioned pulsed steam treatment.

[0089] The entire sequence, from the initial basket loading at point (11), to the soaking treatment in the extraction tank (21), to the transfer and dehydration at station (26), and finally to the steam chamber (31), is precisely timed and coordinated by the PLC (61) to ensure sufficient processing time at each stage while maintaining a continuous production process. Sensors monitoring the basket position, water level, processing time, and other process parameters provide feedback to the PLC to achieve real-time optimization of the transfer sequence.

[0090] Figure 2 The ion extraction system shown operates as an integrated subsystem in the entire bioparticle production process. Control signals from the main PLC (61) regulate the plasma activation time and intensity via the generator (22), the air flow rate to the microbubble diffuser (29), the circulation rate of the washing water between the extraction tank (21) and the separation chamber (23), the operation of the ion separation equipment in the separation chamber (23), and the mechanical actions of various baskets and material handling equipment throughout the process.

[0091] Process parameters such as washing water temperature, pH value, conductivity (reflecting ion content), dissolved oxygen level, and processing time are continuously monitored by sensors and data acquisition systems. The PLC (61) uses this feedback information to maintain optimal extraction conditions and adjusts the operating parameters according to changes in raw material characteristics, environmental conditions, or production requirements.

[0092] Safety interlock devices ensure that personnel cannot access the energized plasma emitter, prevent movement of the basket during plasma activation, and trigger appropriate alarm and shutdown procedures in the event of equipment failure or unsafe conditions.

[0093] Combination Figure 2The described ion extraction system offers several significant advantages in bioparticle fuel production. Compared to traditional washing or leaching methods, wet plasma and microbubble technology achieves higher ion extraction efficiency in a shorter processing time. The use of a multi-oxide composite plasma emitter provides durability and stability in harsh aqueous ion environments. The water circulation and recycling system minimizes fresh water consumption and reduces wastewater discharge. Recovering mineral salts as a byproduct improves process economics and sustainability. Automated control and sequential coordination reduce labor requirements and ensure consistent product quality.

[0094] Most importantly, effectively removing mineral ions from biomass feedstock before subsequent processing stages results in biomass pellets with lower ash content, minimal slagging and scaling during combustion, lower alkali metal and chloride emissions, and superior overall fuel quality and market competitiveness.

[0095] Figure 3 The low-pressure steam purge chamber (31) and its associated steam generation and control system are shown in detail, representing a key and innovative operational phase of this invention. This system achieves effective biomass structural modification and moisture reduction under significantly lower pressure and cost conditions than conventional high-pressure steam treatment processes, while maintaining or even exceeding the quality and fuel performance of biomass pellets produced by high-pressure methods.

[0096] After completion Figure 2 Following the ion extraction and dehydration operations, a portion of the dehydrated biomass located at the transfer station (26) will be transported to the low-pressure steam purging chamber (31) under the coordination and control of the plant's main programmable logic controller (PLC 61). This transfer mechanism includes a conveying system, a robotic transfer arm, or an overhead crane, capable of reliably moving the loading basket from the transfer station (26) into the steam purging chamber (31).

[0097] Biomass material is loaded into stainless steel baskets specifically designed for steam treatment applications. These baskets are made of corrosion-resistant stainless steel grades such as 304, 316, or 316L, offering excellent resistance to the combined effects of high temperatures, moisture, and any residual acidic or alkaline compounds that may be present in the biomass. Perforations are provided in the side walls and bottom of the baskets to allow steam to circulate freely throughout the biomass mass, while also providing structural support to contain the material during processing.

[0098] Each basket is loaded with a predetermined weight of extracted ionized biomass, typically ranging from 50 kg to 500 kg, depending on the size of the purging chamber and the scale of production. The basket load is strictly controlled to ensure that the steam can fully penetrate and achieve uniform treatment, while maximizing the utilization of the purging chamber. Multiple baskets can be loaded into the steam purging chamber (31) simultaneously for batch processing, or they can be fed sequentially for semi-continuous operation.

[0099] The low-pressure steam purge chamber (31) can be constructed as a horizontal cylindrical pressure vessel or a rectangular cavity, made of carbon steel or stainless steel, and designed to safely accommodate steam pressures up to 16 bar. The cavity size is selected based on the required batch volume while maintaining an appropriate length-to-diameter ratio to ensure uniform steam distribution.

[0100] The steam purging chamber (31) is equipped with multiple steam inlets strategically arranged along the periphery of the chamber to ensure uniform steam introduction. Connected to these inlets are multiple specially designed steam nozzles (36), which constitute a novel and important feature of this invention. The geometry and design of these steam nozzles (36) are specifically engineered to stabilize steam handling operations during pulsating purging processes regulated by a fuzzy logic control system.

[0101] The steam nozzle (36) may incorporate a variety of design features, including a convergent-expansion profile for controlling steam velocity and pressure drop, multiple orifices or slits for uniformly distributing the steam flow, adjustable flow area via movable blades or inserts to accommodate different processing schemes, and erosion-resistant materials or coatings for withstanding pulsating flow conditions. The precise geometric parameters of the steam nozzle (36), including orifice diameter, injection angle, nozzle spacing, and internal flow channels, are optimized through computational fluid dynamics analysis and experimental verification to achieve the desired pulsating steam flow characteristics without generating excessive noise, vibration, or mechanical stress on the cavity components.

[0102] One or more condensate drain ports are provided at the bottom of the purge chamber (31) to discharge liquid water formed by the condensation of steam after it comes into contact with the colder biomass. These drain ports are connected to the downstream treatment system via pipes.

[0103] The purge chamber (31) is also equipped with one or more quick-release valves (38) for rapid depressurization of the chamber upon completion of the treatment cycle. These valves are specifically designed to open quickly, transitioning from a fully closed to a fully open state in a very short time to achieve the required depressurization rate.

[0104] The purge chamber (31) is equipped with an inspection door or hatch for loading and unloading baskets. These openings are equipped with a pressure-resistant sealing system and safety interlocks to prevent them from being opened while the chamber is still pressurized.

[0105] Steam is supplied to the purge chamber (31) by a steam boiler (32) specifically designed for the operating pressure range required by this invention. Unlike conventional high-pressure boiler systems that typically operate at 20 to 50 bar and require complex safety systems, the boiler (32) is designed to generate steam at a pressure not exceeding 16 bar and typically operates in the range of 8 to 16 bar, depending on the processing scheme and the type of biomass feedstock.

[0106] The boiler (32) employs a fire-tube boiler design, in which high-temperature combustion gases flow through pipes surrounded by water. This contrasts with the design of water-tube boilers, where water flows through pipes surrounded by hot gases. For the relatively moderate pressure requirements of this system, the fire-tube design offers several advantages, including simpler structure, lower capital costs, less sensitivity to water quality changes, easier maintenance and inspection, and greater tolerance to the inherent thermal cycling in batch or semi-continuous operation.

[0107] It is worth emphasizing that the boiler (32) operates at below 16 bar and employs a fire-tube design, which significantly reduces the risk of scaling in the circulating piping system, a common and troublesome problem in water-tube boiler systems operating at higher pressures. Scaling, caused by the precipitation of dissolved minerals such as calcium carbonate, calcium sulfate, and silica compounds, reduces heat transfer efficiency, restricts flow, and can lead to localized overheating and piping failure. The lower operating pressure and different flow structure of the boiler (32) minimize this tendency to scale, thereby reducing maintenance requirements and improving system reliability.

[0108] The boiler (32) can use a variety of fuel sources, including some biomass pellets produced by the process (thus achieving energy self-sufficiency), natural gas, fuel oil, biomass residue, or other available fuels. Combustion air is supplied by a forced draft fan, and exhaust gases are discharged through a chimney, which may be equipped with appropriate emission control devices that comply with environmental regulations if necessary.

[0109] The boiler (32) is supplied with feedwater from a feedwater tank (33), which stores treated water whose dissolved solids, hardness, and pH are controlled to minimize scaling and corrosion inside the boiler. A feedwater pump maintains the pressure required to inject water into the boiler to overcome steam pressure. Water level control devices and low-water-level safety shut-off devices ensure safe boiler operation.

[0110] A significant and innovative feature of this invention is the integration of a fuzzy logic controller into the main PLC (61) for regulating the pulsating steam purging process. Unlike traditional binary on / off control or simple proportional-integral-derivative (PID) control, fuzzy logic control can perform advanced and intelligent regulation of steam flow based on multiple input parameters and complex operating rules derived from process knowledge and experimental optimization.

[0111] The fuzzy logic controller receives input signals from multiple sensors that monitor cavity pressure at different locations, acquire cavity temperature via thermocouples or resistance temperature detectors, obtain biomass moisture content via dielectric moisture sensors or calculations based on weighing sensors, record processing time via system timers, and monitor steam quality and flow via steam pipeline instruments.

[0112] Based on these inputs and pre-programmed fuzzy logic rules, the controller adjusts the steam inlet valve (37) to form a pulsating steam flow pattern, where steam does not enter the purge chamber (31) in a continuous, steady flow, but rather in controlled pulses. This pulsating pattern is characterized by several key parameters, including pulse frequency (steam pulse delivery rate), pulse duration (the length of time each pulse is active), pulse amplitude (the peak pressure or flow rate reached by each pulse), and pulse waveform (the shape of the pressure-time curve during each pulse).

[0113] According to the present invention, steam treatment is regulated by a fuzzy logic controller to ensure that the steam pressure is maintained below 16 bar, preferably in the range of 8 to 14 bar, throughout the treatment cycle. This pressure range is sufficient to achieve the desired biomass structural modification while avoiding the costs and risks associated with high-pressure systems.

[0114] The purging frequency, i.e., the rate of steam pulse delivery, was maintained within the range of 10 Hz to 50 Hz, equivalent to 10 to 50 pulses per second. Extensive experiments have demonstrated that this frequency range optimizes biomass treatment. Below 10 Hz, the pulsation is too slow to achieve maximum fiber rearrangement and structural modification; above 50 Hz, mechanical and flow dynamics become difficult to control, and diminishing returns occur in improving biomass quality.

[0115] Within an operating range of 10 Hz to 50 Hz, the fuzzy logic controller can dynamically adjust the frequency based on real-time feedback. For example, at the start of a processing cycle, when the biomass moisture content is high, a lower frequency and longer pulse duration can be used to allow sufficient time for steam to penetrate. As the biomass becomes drier and steam flow permeability increases, the frequency can be increased to enhance the mechanical effect of pressure pulsations on the fiber structure.

[0116] The processing time for each batch is pre-programmed into the PLC (61) based on the weight of biomass bagasse, the type of raw material, and the initial moisture content of each stainless steel basket. The typical processing time is 10 to 45 minutes, and raw materials with larger loads or higher moisture content usually require longer processing times.

[0117] The steam purging process implemented in the purging chamber (31) comprises multiple distinct stages, each optimized for a specific treatment objective. This multi-stage approach represents an advancement over simple constant-pressure steam treatment and significantly contributes to the superior quality of the resulting bioparticles.

[0118] In the initial and main processing stages, a pulsed steam flow controlled by a fuzzy logic system is applied to the biomass as described above. This pulsed purging stage typically accounts for 60% to 80% of the total processing time, and its functions include dehumidification through heat transfer and evaporation, removal of volatile organic compounds that contribute little to the calorific value, partial hydrolysis of hemicellulose and other thermally unstable components, initiation of cellulose fiber rearrangement due to alternating expansion and contraction cycles, and disruption of the biomass cell structure to improve subsequent drying and granulation.

[0119] The pulsating action creates dynamic pressure and temperature gradients within the biomass matrix, enhancing mass and heat transfer compared to static steam treatment. Alternating pressure cycles also induce mechanical stress, which helps to disrupt rigid cell wall structures.

[0120] After the pulsating purging phase is completed, the biomass enters the constant pressure phase, during which the purging chamber (31) maintains a steadily increasing pressure for a specific duration. The pressure during this holding phase is maintained between 13 and 16 bar, depending on the type of feedstock being processed. For more difficult-to-process materials such as woody biomass or high-silica straw, processing can be carried out at the higher end of this pressure range, while softer materials such as bagasse can usually be adequately processed at 13 to 14 bar.

[0121] The constant pressure holding phase lasts from 2 to 10 minutes, depending on the biomass loading and the required degree of structural modification. During this phase, the elevated temperature and pressure remain stable under pulsation-free conditions, allowing thermal and chemical reactions to continue. These reactions include further hydrolysis of hemicellulose, partial depolymerization and redistribution of lignin to the fiber surface to act as a natural binder in subsequent pelleting, evaporation of moisture from the internal regions of the biomass pellets, and heat conditioning to make the biomass more suitable for subsequent mechanical densification.

[0122] The final and critical stage of the steam treatment process is the rapid depressurization step, in which the chamber pressure is rapidly reduced from 13 to 16 bar during the holding phase to approximately 1 bar of atmospheric pressure within a very short time of 10 to 25 seconds. This rapid depressurization is achieved by the operation of a rapid release valve (38), which is controlled according to programmed timing signals issued by the main PLC unit (61).

[0123] Rapid depressurization produces several important effects, imparting unique properties to the processed biomass. The sudden pressure drop causes flash evaporation of moisture remaining in the biomass structure, leading to internal vapor expansion and further disrupting cell structure. The explosive pressure release generates mechanical forces, resulting in more fiber separation and rearrangement. More importantly, this rapid depressurization is believed to facilitate carbon chain rearrangement at the molecular level—the reorganization of cellulose and other polymer chains into a more ordered, aligned configuration—enhancing binding capacity during subsequent pelleting and increasing the density and mechanical strength of the final pellets.

[0124] The specific duration of the depressurization phase, which is 10 to 25 seconds, is selected based on the type and load of biomass. If the depressurization is too rapid, less than 10 seconds, it may lead to excessive fragmentation of the biomass structure and generate excessive noise and vibration; if the depressurization is too slow, more than 25 seconds, the beneficial burst effects and molecular recombination associated with flash evaporation cannot be achieved.

[0125] The PLC (61) precisely controls the opening sequence and rate of the quick-release valve (38) to obtain the desired pressure relief curve. The valve can be fully opened in one quick action to obtain the maximum effect, or it can be opened in stages to adjust the pressure relief rate.

[0126] During the entire steam purging process, especially in the pulsating and constant pressure stages, condensation occurs when the steam comes into contact with biomass material at an initial temperature much lower than the steam itself. The condensate accumulates at the bottom of the cavity (31) and is continuously or intermittently discharged through the condensate outlet.

[0127] The condensate is piped to the water supply tank (33), and the device can be connected to... Figure 2 The ion separation tank (23) described herein is the same device, but it can also be a separate, dedicated condensate treatment unit. Within the ion separation tank (23), the condensate is treated to recover valuable solid ionic byproducts extracted from biomass during steam treatment.

[0128] These byproducts include mineral salts, such as potassium chloride and potassium carbonate, leached from biomass by condensate, as well as organic acids and other water-soluble compounds extracted during steam treatment, and fine particulate matter carried over from the biomass. The recovered mineral salts are collected and stored for sale or reuse, while the treated condensate is recycled to the feedwater tank (33) for reuse in the boiler or mineral ion extraction tank (21), thereby saving water and recovering heat energy.

[0129] After the rapid depressurization phase is completed, the cavity (31) returns to atmospheric pressure and can be safely opened. At this time, the biomass after steam treatment is placed in a stainless steel basket (35) and removed from the cavity through the same conveying system or transfer mechanism as during loading, but now flows to the subsequent processing stage.

[0130] like Figure 3 As shown, the processed biomass bagasse is transferred to a multi-layer hot air dryer via a conveyor track system. This dryer corresponds to... Figure 1 The hot air drying unit (41) shown and described in detail in this figure. The conveyor track system can smoothly and continuously transport the basket from the steam chamber to the dryer inlet, thereby reducing handling and lowering the risk of material loss.

[0131] At this stage, the biomass treated with steam has significantly reduced its moisture content compared to before entering the purge chamber, typically from an initial 40% to 60% to about 25% to 35%. However, to achieve the optimal moisture content of 7% to 14% suitable for pelleting, further drying is still required in a hot air dryer (41).

[0132] The entire steam purging operation is continuously monitored and controlled by the main PLC (61). The PLC receives input signals from numerous sensors, including pressure transmitters that monitor the pressure in the chamber and the steam pipeline, temperature sensors installed at multiple locations in the steam system and chamber, humidity sensors that estimate the moisture content of biomass, flow meters that measure the flow rate of steam and condensate, position sensors that confirm the valve status and basket position, and safety devices including pressure relief valves, high-pressure shut-off devices, and emergency shutdown circuits.

[0133] The PLC (61) executes complex control algorithms, including a fuzzy logic control program for pulsating steam modulation, a time control sequence for a multi-stage processing protocol, valve position control commands for the steam inlet valve (37) and the quick release valve (38), boiler combustion rate control to maintain steam supply, and safety interlocks to prevent unsafe operating conditions.

[0134] All process parameters are recorded in the data storage system for use in quality control documentation, process optimization through historical data analysis, and troubleshooting of operational problems. The operator interface terminal allows for manual supervision and intervention when necessary, but once a handling plan is established, the system can operate largely autonomously.

[0135] Figure 3The low-pressure steam purging system shown and described herein offers several advantages that collectively represent a significant advancement in biomass fuel production technology. Operating pressures below 16 bar significantly reduce capital costs for pressure vessels, piping, and safety systems compared to conventional 20-30 bar systems. The fire-tube boiler design provides a reliable, low-maintenance steam generation method suitable for the medium pressure requirements of this system. Fuzzy logic-controlled pulsed steam flow, through intelligent dynamic adjustment, enables biomass to achieve structural modification effects equivalent to high-pressure systems. A multi-stage processing scheme is optimized at each stage for different conditioning objectives. A specially designed steam nozzle geometry ensures stable and uniform steam distribution during pulsed operation. The rapid depressurization stage produces unique carbon chain rearrangement and fibrous structure effects that cannot be achieved through gradual depressurization. Integration with the condensate recovery system captures valuable byproducts and conserves water and energy.

[0136] Most importantly, the biomass pellets produced by this system can meet or exceed those produced by high-pressure processes in terms of calorific value, density, durability and combustion performance, but at a significantly lower cost and risk, thus making advanced biomass fuel production more accessible to a wider range of agricultural communities and business operators.

[0137] Figure 4 The final processing stages of the bio-pellet fuel production system according to the present invention are shown, including dehumidification, lignin addition and electromagnetic activation, pelleting, and product collection. These stages convert steam-treated biomass into finished bio-pellets with excellent density, mechanical strength, calorific value, and combustion performance. A novel feature shown in the figure is the use of low electromagnetic wave (LEW) treatment to activate the added lignin and enhance pellet binding properties, representing a significant advancement compared to conventional pelleting processes.

[0138] Finish Figure 3 The biomass treated by the low-pressure steam purging will be transferred to Figure 4 The multi-layer drying unit (70) shown is illustrated. This drying unit corresponds to... Figure 1 The hot air drying unit (41) mentioned in the text is designed to efficiently reduce the moisture content of biomass after steam treatment from about 25% to 35% to the optimal range of 7% to 14% required for pelleting.

[0139] The multi-layer drying unit (70) consists of a vertically or inclined cavity with multiple horizontal drying plates or trays stacked inside. Steam-treated biomass enters from the top layer and moves downwards layer by layer via gravity, mechanical raking, or a conveying mechanism. This multi-layer arrangement offers several advantages, including providing a larger drying surface area within a compact footprint, extending residence time for thorough dehydration, achieving gradual temperature exposure through higher temperatures in the lower layers, and enabling efficient heat utilization through counter-current or cross-flow air-biomass contact.

[0140] Heated dry air is introduced into the drying unit (70), typically in a counter-current configuration, so that the hottest air contacts the drier lower layer of biomass, while the cooler air contacts the wetter upper layer of biomass. The dry air inlet temperature is typically in the range of 100°C to 180°C, depending on the heat source and biomass characteristics. The airflow rate and temperature are controlled to achieve the target moisture content while avoiding over-drying, coking, or thermal degradation.

[0141] The heat of the dry air can come from the direct combustion of biomass pellets or biomass residue, heat exchange through boiler (32) exhaust gas, dedicated natural gas or oil burners, or waste heat recovered by other equipment. Utilizing the heat generated from the combustion of biomass pellets can create a partially self-sufficient energy system, thereby reducing external energy demand.

[0142] As the biomass moves downwards layer by layer, moisture continuously evaporates and is carried away by the flowing air. The moist exhaust gas is discharged from the drying unit, and entrained biomass particles can be recovered by cyclone separators, filters, or scrubbers before being discharged into the atmosphere or recycled.

[0143] Temperature, airflow, and moisture content in the drying unit (70) are monitored by sensors connected to the main PLC (61), which adjusts operating parameters to maintain a stable moisture content in the dried biomass product. The residence time of biomass in the drying unit is typically 15 to 45 minutes, depending on the initial moisture content, airflow conditions, and tier configuration.

[0144] The dried biomass is discharged from the bottom of the multi-layer drying unit (70) with its moisture content controlled in the optimal range of 7% to 14%, typically with a target value of 10% to 12%, to achieve the best pelleting performance.

[0145] A unique and advantageous feature of this invention is the addition of supplemental lignin to the dried biomass prior to pelleting. Lignin is a complex organic polymer naturally found in plant cell walls, providing structural rigidity and binding cellulose fibers together. While biomass feedstocks naturally contain lignin, typically comprising 15% to 30% of their dry weight, the additional addition of lignin acts as a natural binder, thereby enhancing pellet formation, increasing pellet density and mechanical strength, improving pellet durability during handling and transportation, and increasing the calorific value of the final biomass pellets, as lignin has a higher carbon content than cellulose or hemicellulose.

[0146] like Figure 4 As shown, the dried biomass discharged from the drying unit (70) is mixed with added lignin (71) at a ratio of 10% to 20% of the dry weight of the biomass. For example, if 100 kg of dried biomass is processed, 10 to 20 kg of lignin is added and thoroughly mixed with the biomass. The lignin (71) can be derived from a variety of sources, including kraft lignin, a byproduct of the pulping and papermaking industry; lignin sulfonates from sulfite pulping processes; organic solvent lignin from alternative pulping methods; hydrolyzed lignin from cellulosic ethanol production; or pyrolyzed lignin obtained through biomass thermal treatment.

[0147] Lignin can be supplied in various forms, including dry powder with a particle size typically less than 500 micrometers, granular form with controlled particle size distribution, liquid or paste form softened under heating conditions, or pre-activated form with enhanced reactivity through chemical or thermal treatment. The particle size and morphology of lignin are selected based on the ease of uniform mixing with dry biomass and the need to optimize subsequent electromagnetic activation and granulation performance.

[0148] The mixing of dried biomass with supplemental lignin (71) can be accomplished using a variety of mixing equipment, including belt mixers, paddle mixers, drum mixers, or high-intensity mixers, located between the outlet of the drying unit (70) and the inlet of the LEW chamber (72). The mixing time is controlled to achieve a uniform distribution of lignin throughout the biomass mass, typically requiring 2 to 10 minutes depending on the type of mixer and batch size.

[0149] After the dried biomass is mixed with supplemental lignin (71), the biomass-lignin mixture is fed into a low electromagnetic wave (LEW) generating chamber (72), which is a novel and key component of this invention. The LEW treatment system activates and modifies lignin molecules, thereby enhancing their adhesion properties in subsequent granulation, resulting in granules of superior quality compared to those without electromagnetic treatment.

[0150] The LEW generating chamber (72) is designed as a closed container or cavity through which the biomass-lignin mixture passes. This chamber can be designed as a horizontal pipe or rectangular conduit, a vertical column for upward or downward flow, or a rotating drum that tumbles the material during processing. Chamber size and residence time are selected to ensure sufficient electromagnetic field exposure for the material, typically 1 to 5 minutes.

[0151] The cavity (72) is made of non-metallic materials or equipped with appropriate shielding and safety measures to contain electromagnetic radiation and prevent it from interfering with surrounding equipment or exposing personnel. The cavity may be made of high-temperature resistant plastics, ceramics or composite materials.

[0152] Low electromagnetic waves are generated within the cavity (72) and applied to the biomass-lignin mixture by a low electromagnetic wave (LEW) generator (73). The LEW generator (73) includes an electronic power supply and control circuit, an electromagnetic wave generation circuit that operates at a specified frequency, a power amplification stage for achieving the required field strength, and a safety monitoring and shutdown system.

[0153] The electromagnetic waves generated by the LEW generator (73) are “low-frequency” electromagnetic radiation, typically operating in the range of 10 kHz to 10 MHz, more preferably 50 kHz to 1 MHz. This frequency range is chosen to achieve optimal interaction with lignin molecules while avoiding the use of high-frequency microwaves that would cause overall volume heating rather than selective molecular activation, as well as ultra-low frequencies with too weak molecular effects.

[0154] The electromagnetic field strength within the cavity (72) is controlled to provide sufficient energy to activate lignin without causing overheating or thermal degradation of the biomass. The field strength is typically between 100 V / m and 10,000 V / m, depending on the cavity geometry, frequency, and processing time.

[0155] A particularly innovative feature of the LEW processing system is the arrangement of ferrite coil inductors around the outer wall of the LEW cavity (72). These ferrite coil inductors act as electromagnetic field generating and shaping elements, creating the desired electromagnetic environment inside the cavity.

[0156] Ferrite cores are composed of ceramic materials containing iron oxides combined with other metal oxides such as manganese, zinc, or nickel. Ferrite materials have high permeability, enabling efficient concentration and guidance of magnetic flux. Copper coils are wound around the ferrite core, through which alternating current at a frequency generated by a LEW generator (73) passes.

[0157] Ferrite coil inductors are arranged in a ring around the cavity (72), typically in multiple rings or arrays along the length of the cavity. The number, spacing, and energizing mode of the inductors are designed to create a uniform electromagnetic field inside the cavity, ensuring that all passing biomass-lignin mixtures are treated uniformly.

[0158] According to an important feature of the invention, the ferrite coil inductor is energized in a manner that provides a pulsating electromagnetic wave to the biological solid mixture within the cavity (72). This electromagnetic field is not continuously and stably generated, but rather modulated into a pulsed or oscillating intensity. The pulsating electromagnetic wave can be characterized by several parameters, including the pulse frequency, i.e., the rate of change of the field strength, typically from 1 Hz to 100 Hz; the pulse duty cycle, i.e., the ratio of the "on" time to the total period time; the pulse amplitude, i.e., the peak field strength during each pulse; and the pulse waveform, which can be a sine wave, square wave, triangular wave, or other shape.

[0159] Compared to a steady-state electromagnetic field, this pulsating electromagnetic field is considered to be more effective in activating lignin molecules. The alternating field strength can induce molecular oscillations, promote periodic heating and cooling that facilitates molecular recombination, enhance the penetration of electromagnetic energy into biomass-lignin mixtures, and achieve a more uniform energy distribution throughout the material.

[0160] The low electromagnetic wave treatment in the cavity (72) produces a variety of beneficial effects on the lignin molecules in the mixture. The electromagnetic field induces the polar functional groups in the lignin molecules to rotate and oscillate, and causes local heating through the dielectric loss mechanism. This selective heating of lignin is more pronounced than that of cellulose because lignin has a higher loss tangent in this frequency range, which softens the lignin molecules and increases their mobility.

[0161] Furthermore, electromagnetic energy may induce limited depolymerization or structural rearrangement of lignin molecules, thereby generating more active sites that can be used for bonding. Free radical formation may also occur, enhancing lignin's ability to form covalent bonds during subsequent granulation. Electromagnetic treatment may also promote the migration of lignin molecules to the fiber surface, allowing them to most effectively act as intergranular binders.

[0162] The overall effect of LEW treatment is to enhance the adhesion of treated lignin in subsequent pelleting operations. When the electromagnetically activated biomass-lignin mixture is subjected to heat and pressure in the pelleting unit (78), the activated lignin flows more easily, penetrates more effectively between the fiber surfaces, and forms a stronger bond than unactivated lignin. As a result, the resulting pellets have superior mechanical properties, including higher density, greater mechanical strength and abrasion resistance, better handling and storage durability, and a lower tendency for pellet degradation or powder formation.

[0163] Another benefit of LEW treatment and enhanced lignin bonding is the increased calorific value of the final biomass pellets. The improved bonding results in a denser pellet with a higher mass per unit volume. Since lignin has a higher calorific value per unit mass than cellulose (approximately 25 MJ / kg for lignin and 17 MJ / kg for cellulose), the addition of 10% to 20% lignin, combined with better densification, typically yields pellets with a calorific value of 18 to 21 MJ / kg, compared to only 15 to 17 MJ / kg for untreated biomass pellets without added lignin.

[0164] The operation of the LEW generator (73) and the ferrite coil inductor array is controlled by the main PLC (61), which is responsible for adjusting the electromagnetic frequency and intensity, pulsation modulation parameters (including pulse frequency and duty cycle), processing time based on the speed of material flow through the cavity (72), as well as power consumption and equipment status.

[0165] A temperature sensor inside the cavity (72) is used to monitor the temperature of the biomass-lignin mixture to ensure that overheating does not occur. If the temperature exceeds a safe threshold, the PLC (61) can reduce electromagnetic power or increase the material flow rate to prevent thermal damage.

[0166] After being discharged from the LEW chamber (72), the electromagnetically treated biomass-lignin mixture is immediately transported to the pelleting unit (78) for pelleting while the lignin is still in an enhanced reactive state. This rapid transfer minimizes the time it takes for the lignin activation effect to be weakened by cooling or molecular relaxation.

[0167] The pelletizing unit (78) includes a pellet mill or pellet press for compressing and extruding the treated biomass-lignin mixture through a die to form cylindrical pellets of controlled size. The pelletizing unit (78) can be configured as a flat die pellet mill in which biomass is pressed by pressure rollers through holes in a stationary flat die; or as a ring die pellet mill in which biomass is pressed by stationary or rotating internal pressure rollers through holes in a rotating cylindrical die; or as a hydraulic pellet mill that uses direct hydraulic pressure to compress biomass into pellets.

[0168] The mold is typically heated to 60°C to 120°C to promote lignin softening and bonding. Under the combined effects of pressure typically reaching 100 to 300 MPa on the mold surface, elevated temperature, and shear force experienced by the material as it passes through the mold orifice, the activated lignin flows, covers the fiber surface, and binds the particles into a cohesive whole.

[0169] As the compressed biomass-lignin mixture is forced through die orifices typically 6 to 8 millimeters in diameter, it is extruded from the die as continuous cylindrical rods. A cutting mechanism installed at the die exit cuts these cylindrical rods into controlled-length particles, typically 10 to 40 millimeters in length, thus forming uniform cylindrical particles.

[0170] The granules exit the mold at a relatively high temperature, approximately 60°C to 90°C, and are then conveyed to a cooling zone or cooling column, where they come into contact with ambient air or cooling air. This cooling process allows the softened lignin to re-solidify, thereby locking in the granule structure and forming mechanically stable and durable granules.

[0171] The pelletizing unit (78) is equipped with a drive motor. Figure 4 The motor, marked "AC", is used to provide the mechanical power required to form granules. This motor can be a variable-speed AC motor controlled by a frequency converter, thereby adjusting the granulation speed to optimize product quality and energy efficiency. The PLC (61) controls the motor speed based on real-time monitoring of raw material characteristics, desired production rate, and granule quality.

[0172] The final bio-solid pellets are discharged from the pelleting unit (78) and collected in a bio-particle collection bin (79), which can be configured as a storage hopper, a conveying system, or directly connected to packaging equipment. The collection bin (79) can temporarily store the finished pellets and can be equipped with a level sensor to notify the operator when the bin is full and needs to be emptied.

[0173] After leaving the collection bin (79), the pellets can be transported to the packaging station and packed into consumer packaging, typically 10 to 25 kg / bag; they can also be packed into bulk bags or ton bags, typically 500 to 1000 kg; or stored in bulk silos for large-scale commercial use.

[0174] pass Figures 1 to 4 The finished biomass pellets produced by the process shown have excellent quality characteristics, including a high bulk density typically of 650 to 800 kg / m³, a uniform cylindrical shape of 6 to 8 mm in diameter and 10 to 40 mm in length, a moisture content of 7% to 14%, a high calorific value of 18 to 21 MJ / kg on a dry basis, low ash content typically below 3% after pre-ion extraction treatment, excellent durability with very little powder generation during handling, low alkali metal content that reduces slagging and fouling during combustion, and consistent combustion performance suitable for automated feeding systems.

[0175] Figure 4The final stage of the integrated biogranule production process is shown. The material stream continuously enters from the drying unit (70), undergoes lignin addition and mixing, is processed in the electromagnetic activation chamber (72), granulates in the pelletizing unit (78), and is finally collected in the collection bin (79). The entire sequence is coordinated by a PLC (61) to maintain a stable production flow and consistent product quality.

[0176] Integrating low electromagnetic wave (LEW) treatment between drying and granulation is a novel process innovation that significantly improves particle quality without the need for high-pressure equipment, chemical additives, or complex heat treatments. The LEW treatment step adds only minimal capital costs and energy consumption, while significantly improving particle density, strength, and calorific value.

[0177] Figure 4 The drying, electromagnetic treatment, and pelletizing system shown offers several key advantages. A multi-layer drying unit efficiently reduces moisture to optimal pelletizing levels. Supplemental lignin addition (10% to 20%) enhances adhesion and increases calorific value. Low electromagnetic wave treatment using pulsating ferrite coil inductors activates lignin, resulting in superior adhesion properties. LEW activation produces pellets with higher density and strength compared to conventional processes. The increased calorific value of 18 to 21 MJ / kg allows biomass pellets to compete with coal and outperform many other biomass fuels. The entire system operates at atmospheric pressure and moderate temperature, avoiding the costs and risks associated with high-pressure or high-temperature processes.

[0178] Ion extraction ( Figure 2 Low-pressure pulsating steam purging ( Figure 3 ) and LEW-enhanced granulation ( Figure 4 This combination constitutes a complete and innovative biomass fuel production process that can achieve excellent product quality through physical processing methods without the use of highly corrosive chemicals, extreme pressure, or high capital investment.

[0179] Figure 5 Another embodiment of the biopellet fuel production method according to the invention is shown, in which the process is simplified by eliminating the low-pressure steam purging stage, while retaining the beneficial mineral ion extraction pretreatment. This simplified configuration provides a lower-cost and less complex alternative, although the pellets produced may not achieve the superior quality achieved by the full process including steam purging and electromagnetic treatment, but still produce biopellet that is significantly better than pellets made from untreated biomass.

[0180] Figure 5The alternative processes shown are particularly suitable for situations where minimizing capital costs is a priority, existing drying and granulation equipment is available and can be integrated with the ion extraction system, the raw material characteristics requirements are low and do not require enhanced steam treatment, the production scale is small enough to justify the investment in steam purging equipment, or the market has lenient requirements for particle quality that can be met without enhanced steam treatment.

[0181] like Figure 5 As shown, the simplified process includes the following main stages and equipment components, which are coordinated and controlled by the main programmable logic controller (PLC 61).

[0182] The pre-cut biomass feedstock enters from the input point (11) and is transported to the mineral ion extraction tank (21), the process of which is similar to... Figure 1 and Figure 2 The above is completely consistent. The ion extraction system is also the same as the aforementioned implementation method, using wet plasma and washing water in the microbubble generator (22) activation tank (21) to extract alkali metals, alkaline earth metals, chlorine, sulfur and other mineral pollutants from biomass.

[0183] In this simplified process, ion extraction plays the same role as in the complete process, bringing several beneficial effects, including reducing ash-forming minerals that cause slagging and fouling during combustion, removing chlorine and sulfur compounds that lead to corrosive emissions, extracting alkali metals that lower the ash melting point, especially potassium and sodium, and improving overall fuel quality and combustion performance.

[0184] The biomass residence time, wet plasma and microbubble treatment intensity, and all other operating parameters in the ion extraction tank (21) can be the same as those used in the complete process, or can be adjusted according to the specific requirements of the simplified process. Since the biomass after ion extraction will not undergo steam purging in the subsequent process, the ion extraction time can be extended or the treatment intensity can be increased to maximize mineral removal in this single pretreatment stage.

[0185] Water circulates between the ion extraction tank (21) and the ion separation system (33) via a recirculation line (25), in a manner consistent with the description in the aforementioned figure. The ion separation system (33) removes dissolved and suspended mineral salts from the wash water using precipitation, filtration, evaporation, ion exchange, or other suitable separation methods.

[0186] The separated mineral salts are collected and stored in an ion-solid storage tank (24). An important and valuable feature of this invention, particularly in… Figure 5This is highlighted in the context that the wash water used for mineral ion extraction can be reused for the washing operation through replenishment and refilling pipelines. The mineral-containing wash water is not directly discarded as waste, but is first treated in the ion separation system (33) to reduce excessive mineral concentration, and then recycled back to the extraction tank (21) for continued use.

[0187] This water recycling method offers several benefits, including reduced fresh water consumption, lower wastewater discharge and related environmental impact, preservation of the activated water properties generated by the wet plasma system, and recovery of valuable mineral byproducts instead of them being lost with wastewater.

[0188] Importantly, even after treatment by the ion separation system (33), the recycled wash water still retains a certain concentration of various mineral ions, including nitrogen compounds (ammonium nitrogen, nitrate nitrogen), phosphorus compounds (phosphate), potassium ions, calcium and magnesium ions, and trace mineral elements. This residual mineral content is not a disadvantage; rather, it makes this used water particularly valuable for agricultural applications.

[0189] This used wash water, rich in various mineral ions, especially the three macronutrients essential for plant growth—nitrogen (N), phosphorus (P), and potassium (K)—can be beneficially utilized as an agricultural nutrient solution. It can be applied directly as liquid fertilizer to crops or pasture, diluted for irrigation to provide nutrients, used in hydroponic and fertilization irrigation systems, or even further processed to concentrate it into commercial liquid fertilizer products.

[0190] This dual utilization of mineral ions extracted from biomass constitutes an excellent example of the circular economy principle, where waste from one process becomes a valuable input in another. Biomass naturally absorbs these minerals from the soil during its growth, and these minerals are released during ion extraction, allowing them to be recycled and returned to agricultural land, thus achieving a closed-loop nutrient system and enhancing the overall sustainability and economic efficiency of biomass pellet production systems.

[0191] The ability to simultaneously produce high-quality bio-pellet fuel and valuable agricultural nutrient solutions from the same biomass feedstock offers significant economic advantages and can create additional revenue streams, thereby improving the financial viability of bio-pellet production facilities, especially suitable for agricultural regions that require both fuel and fertilizer.

[0192] exist Figure 5 In the simplified process shown, the biomass after ion extraction is directly sent from the ion extraction tank (21) to the drying unit (41), completely bypassing the drying process. Figure 1 and Figure 3 The low-pressure steam purge chamber (31) is a key component of the complete process. This direct transfer is in Figure 5The direction of flow is indicated by an arrow pointing directly from the trough (21) to the dryer (41).

[0193] Eliminating the steam purging stage reduces capital costs by eliminating the need for a steam boiler (32), steam purging chamber (31), related piping and valves, fuzzy logic control system for pulsating steam treatment, and quick pressure relief valve; it also reduces operational complexity by eliminating a process stage that requires skilled operation and monitoring; it reduces energy consumption by eliminating the need for steam generation; and it reduces overall production time by shortening the process cycle.

[0194] However, eliminating steam purging also means that biomass cannot obtain the beneficial structural modifications brought about by pulsed steam treatment, including the rearrangement and compaction of cellulose fibers, partial hydrolysis and redistribution of hemicellulose and lignin, the formation of microcracks that are conducive to pelleting and bonding, and the carbon chain rearrangement effect induced by rapid depressurization.

[0195] Therefore, while biomass pellets produced using simplified processes are superior to pellets made from completely untreated biomass, their density, mechanical strength, and calorific value may not reach the levels of pellets produced using complete processes. This represents a trade-off between equipment cost and product quality, which is acceptable or even a better choice in certain applications and markets.

[0196] In the simplified process, the moisture content of ion-extracted biomass entering the drying unit (41) is typically higher than that of steam-treated biomass because steam treatment itself has the additional effect of significant dehumidification. Therefore, the initial moisture content of ion-extracted biomass entering the dryer can be 40% to 65%, while that of steam-treated biomass is typically 25% to 35%.

[0197] Therefore, the drying unit (41) in the simplified process must remove more moisture to achieve the target moisture content of 7% to 14% required for granulation. This means that compared to the drying requirements in the full process, it may require longer drying time, higher drying air temperature or airflow rate, larger dryer capacity, or higher energy consumption.

[0198] The drying unit (41) can be configured as a multi-layer dryer, drum dryer, belt dryer or other suitable drying equipment, as described above. The dryer operates under the control of a PLC (61), which monitors and adjusts the temperature, airflow and residence time to ensure the consistency of the moisture content of the dried product.

[0199] The heat source for the dryer can be derived from the combustion of biomass pellets or biomass residue, natural gas or oil burners, waste heat recovery, or other available energy sources. In facilities employing simplified processes, since there is no steam boiler (32) available to provide waste heat during drying, alternative heat sources must be used.

[0200] After being dried, the ion-extracted biomass is discharged from the drying unit (41) and enters the granulation unit (51), the configuration of which can be similar to that of the granulation unit (51). Figure 4 The pelletizing unit (78) described herein. The pelletizing unit (51) includes a pellet mill or pellet press for compressing and extruding dried biomass through a die to form cylindrical pellets.

[0201] exist Figure 5 In the simplified process shown, the biomass did not undergo... Figure 4 The aforementioned lignin addition and electromagnetic treatment. Therefore, the pelleting process relies entirely on the natural lignin content of the biomass and the binding effect generated by pressure, temperature, and shear force in the pellet mill. The resulting pellets may have a slightly lower density and mechanical strength than those treated with electromagnetic enhancement, but still form coherent and usable fuel pellets suitable for many applications.

[0202] The pelletizing unit (51) operates under the control of a PLC (61), which is responsible for adjusting the mold temperature, compression pressure, pellet mill speed, and other parameters to optimize pellet quality. The finished bio-particles are discharged from the pelletizing unit (51) and collected in a collection bin or conveying system, such as... Figure 5 The collection chamber shown at the output of unit (51).

[0203] The main programmable logic controller (PLC 61) is responsible for coordinating all operations in the simplified process, including the time and sequence control of biomass from input point (11) through ion extraction (21) to drying (41) and granulation (51), control of ion extraction intensity and duration, regulation of water circulation between tanks (21) and (33), monitoring of ion separation and salt recovery in tanks (33) and (24), control of drying parameters required to achieve target moisture content, and regulation of granulation conditions required to produce high-quality granules.

[0204] Although the simplified process has fewer stages than the complete process, the control system must still ensure that all operations are properly coordinated and that product quality standards are maintained. The PLC (61) can be the same as the controller used in the complete process, except that some control modules are disabled or bypassed in the simplified mode.

[0205] use Figure 5The simplified process layout shown for producing biomass pellets still achieves several important quality improvements compared to pellets made from completely untreated bagasse. These improvements include: effective removal of mineral ions, resulting in ash content typically reduced to 2% to 4%, compared to 4% to 8% for untreated biomass; reduced tendency for slagging and scaling during combustion due to lower alkali metal content; lower chlorine and sulfur content, resulting in fewer emissions and less corrosive combustion products; and a higher calorific value, typically 16 to 18 MJ / kg, compared to 14 to 16 MJ / kg for untreated biomass pellets.

[0206] However, the granules obtained by the simplified process usually cannot achieve the superior properties of granules produced by the complete process, which includes steam purging and electromagnetic treatment; the latter typically has a calorific value of 18 to 21 MJ / kg, a bulk density of 650 to 800 kg / m³, and excellent mechanical strength and durability.

[0207] Pellet produced by simplified processes typically have a calorific value of 16 to 18 MJ / kg, a bulk density of 550 to 650 kg / m³, and good, but not outstanding, mechanical properties. Nevertheless, these properties are still quite acceptable for many applications and represent a significant improvement over untreated biomass pellets.

[0208] Figure 5 The simplified process configuration shown offers several economic and practical advantages, making it a better choice in certain situations, including significantly reduced capital investment due to the elimination of steam boilers, steam purge chambers, and related equipment; reduced operational complexity by minimizing the need for highly skilled operators and complex maintenance; reduced energy consumption due to the elimination of steam generation; shorter production cycles by omitting the steam treatment stage; and easier retrofitting of existing pellet production facilities by simply adding an ion extraction pretreatment stage.

[0209] For agricultural cooperatives, small-scale producers, or operators in developing regions with limited capital but abundant agricultural biomass, simplified processes may represent the optimal balance between improved product quality and investment requirements. The ability to simultaneously produce improved biomass pellet fuel and valuable agricultural nutrient solutions from wash water also enhances the economic attractiveness of even simplified processes.

[0210] Therefore, the present invention covers Figures 1 to 4 The complete process shown also covers Figure 5 The simplified alternative process is shown. The choice between these two configurations can be based on available capital budget, desired product quality specifications, production scale, characteristics of available raw materials, availability of energy and utilities, market demand for high-quality pellets and price premiums, as well as the overall business model and strategic objectives.

[0211] In some cases, facilities can be adopted first. Figure 5 The simplified configuration shown allows for future additions of steam purging and electromagnetic treatment stages as production increases and capital requirements rise. The modular nature of the process makes this phased implementation possible.

[0212] Alternatively, a facility can operate two process configurations in parallel, using a simplified process to produce standard-grade pellets for price-sensitive markets, while using a complete process to produce premium-grade pellets for applications that require higher quality and are willing to pay higher prices.

[0213] Regardless of the process configuration used, both embodiments of the present invention offer significant sustainability and environmental benefits, including converting agricultural waste biomass into valuable renewable fuels, reducing air pollution from open burning of agricultural residues, replacing fossil fuels with renewable biomass energy, recovering and reusing mineral nutrients in agriculture, minimizing water consumption through wash water recycling, and producing cleaner fuels with lower emissions than untreated biomass.

[0214] Figure 5 While the simplified process shown cannot achieve the highest level of product quality, it still makes an important contribution to sustainable energy production and the principles of the circular economy, and may be more suitable for widespread implementation in agricultural regions around the world due to its greater accessibility and practicality.

[0215] It should be understood that Figure 5 This is not merely illustrating a single, separate process, but rather demonstrating that the ion extraction stages (21, 22, 33, 24) can serve as a valuable independent pretreatment step even without subsequent steam purging. This flexibility reflects the modular nature of the invention and the independent value of each process stage.

[0216] Equipped Figures 1 to 4 A complete process facility can be temporarily used during boiler maintenance, when feedstock quality is high and steam treatment is not required, or when market demand demands maximum production throughput while accepting a partial decrease in quality. Figure 5 Run in the simplified mode shown.

[0217] Conversely, facilities initially built with simplified processes can be upgraded by adding steam purging stages, electromagnetic treatment stages, or both, when economic conditions permit or market demand for higher quality particles increases.

[0218] This flexibility and scalability constitute a significant practical advantage of the invention, making it suitable for implementation under different production scales, economic environments, and market demands.

[0219] Example Example 1: Extraction of ions from licorice root biomass A series of comparative tests were conducted to demonstrate the effectiveness of wet plasma and microbubble methods in extracting metal ions and organic compounds from licorice root biomass.

[0220] In the control experiment, 200 grams of licorice root were soaked in 1.5 liters of distilled water at room temperature for 2 hours without any treatment. The ion content and water quality parameters of the resulting water sample were then analyzed.

[0221] The second set of tests was conducted under the same conditions, using 200 grams of licorice root and 1.5 liters of distilled water, but the samples were subjected to 45 minutes of wet plasma and microbubble treatment at a power of 53 W. The temperature was maintained between 45°C and 52°C during the treatment. The resulting water samples were then analyzed using the same analytical methods as the control group.

[0222] The results showed that the conductivity of the untreated control group was 723 µS / cm after soaking for 2 hours; in contrast, the conductivity of the water treated with wet plasma and microbubbles reached 2,621 µS / cm, an increase of 262%. This significant improvement indicates that the wet plasma and microbubble method can significantly enhance the extraction efficiency of ionic substances from biomass compared with simple soaking.

[0223] Subsequently, 300 mL of the treated solution was subjected to reverse osmosis separation. This process yielded 60 mL of clear permeate with low ion content and 240 mL of concentrated solution with a darker color, higher ion content, and greater organic matter content. Ion concentration analysis was then performed on both fractions separately.

[0224] Analytical results show that this method can effectively separate key ions, including potassium (K⁺), sodium (Na⁺), magnesium (Mg²⁺), manganese (Mn²⁺), and chloride (Cl⁻). The high-ion concentrate was then further recovered as solid compounds by centrifugation.

[0225] This embodiment demonstrates that wet plasma combined with microbubble treatment and membrane separation can effectively extract and recover mineral ions from biomass feedstocks.

[0226] The bagasse processed according to the method of this disclosure was then densified and pelletized to prepare bio-particles suitable for use as solid biofuel. Representative samples of the resulting bio-particles were sent to an independent laboratory for analysis, and the test results showed that they achieved measurable and statistically significant improvements in several key performance parameters.

[0227] In terms of carbon content, the treated biomass pellets increased from 43.1% to 47.6%, a net increase of 4.5 percentage points, or approximately 10.44% relatively. In terms of calorific value, the treated biomass pellets increased from 2,815 kcal / kg to 4,301 kcal / kg, a net increase of 1,486 kcal / kg, or approximately 52.78% relatively. Furthermore, the potassium content decreased significantly from 4,082 mg / kg to 1,053 mg / kg, and the ash content also decreased from 2.23% to 1.82%.

[0228] The above experimental results confirm and verify that the method disclosed herein can bring about significant and repeatable improvements in carbon content, calorific value, potassium content and ash content, thereby proving that the biomass produced according to the present invention is suitable for use as a high-quality solid biofuel.

[0229] Example 2A: Extraction of ions from sugarcane bagasse A series of comparative tests were conducted to demonstrate the effectiveness of wet plasma and microbubble methods in extracting mineral ions and organic compounds from sugarcane bagasse.

[0230] In the control experiment, 150 grams of sugarcane bagasse were mechanically cut into lengths of 6 to 8 centimeters and then soaked in 1.5 liters of room temperature distilled water for 2 hours without any treatment. The ion content and water quality parameters of the resulting water sample were then analyzed.

[0231] The second group of tests was conducted under the same conditions, using 150 grams of sugarcane bagasse of the same size and 1.5 liters of distilled water, but the water sample was subjected to wet plasma and microbubble treatment at a power of 33.7 W for 45 minutes. The temperature was maintained between 38°C and 48°C during the treatment. The resulting water sample was then analyzed using the same analytical methods as the control group.

[0232] The results showed that the conductivity of the untreated control group was 444 µS / cm after soaking for 2 hours; while after treatment with wet plasma and microbubbles, the conductivity increased to 590 µS / cm, an increase of 33%. This result indicates that compared with simple soaking, the wet plasma and microbubble method can enhance the extraction of ionic substances from sugarcane bagasse.

[0233] This embodiment demonstrates that wet plasma and microbubble treatment is effective for extracting mineral ions from fibrous agricultural biomass feedstocks such as bagasse.

[0234] Example 2B: Scale-up Experiment of Ion Extraction from Sugarcane Bagasse Scale-up experiments were conducted to demonstrate the effectiveness of the wet plasma and microbubble method at larger production volumes.

[0235] The experiment used 15 liters of distilled water, designated as control sample C5, and 2,385 grams of dried sugarcane bagasse, cut into cubes approximately 15 mm in size. The bagasse was completely submerged in the distilled water. Ion extraction was performed using two PB-2P wet plasma and bubbling units, operating at 7.35 amperes for 30 minutes. The treated water sample was designated SC-T30 and sent for analysis.

[0236] Laboratory analysis showed a significant increase in extractable substances compared to control distilled water. Cations increased from 0 ppm to 105.2 ppm, primarily potassium (K⁺); anions increased from 0 ppm to 83.57 ppm, primarily nitrate (NO⁻), chloride (Cl⁻), and sulfate (SO₄²⁻); organic matter increased from 0 ppm to 4,579 ppm; and sugar content increased from 0% to 0.4% Brix, as determined using a digital refractometer. The higher organic matter and sugar content indicate that residual sugar compounds in the bagasse structure have been extracted.

[0237] The process consumes 130 watts of power during a 30-minute treatment, with a total energy consumption of 65 watt-hours. This energy consumption is significantly lower than that of high-pressure steam explosion methods operating above 30 bar; it is also energy-efficient compared to low-pressure steam purging processes, while effectively removing ionic contaminants from the feedstock.

[0238] This scaled-up example demonstrates that, under near-production-scale conditions, the wet plasma and microbubble method can effectively extract anions and cations from bagasse. By removing salt ions from the raw material, the resulting biomass pellets achieve a higher energy density than those without ion extraction pretreatment.

[0239] Example 3A: Low-pressure pulse steam treatment of licorice root Pre-cut licorice root residue was subjected to pulsed steam purging at 7 bar. The pulse cycle consisted of a 5-second "on" phase and a 2-second "off" phase. The treatment lasted for 20 minutes, with a power consumption of 2.15 kW. The steam condensate was collected during the treatment for subsequent analysis.

[0240] During the treatment, the temperature of the licorice root residue was recorded at 150°C during the "on" phase and 95°C during the "off" phase, indicating that the application of pulsed steam brought about a significant thermal cycling effect.

[0241] The steam-treated residue was air-dried and then dry-blended with a soft biomass substrate. The gasification products were slightly darker in color than the untreated material. Both the low-pressure steam-treated licorice root residue and the untreated control sample were granulated and subjected to calorific value determination and combustion testing.

[0242] Laboratory analysis showed that the calorific value of the steam-treated slag increased by 12.5% ​​compared to the untreated material. The steam condensate collected during the treatment process was milky yellow with a conductivity of 4320 µS / cm, indicating that a large number of mineral ions and organic compounds were extracted during the pulsed steam purging process.

[0243] The weight of the slag before treatment was 380 grams, and the weight after steam treatment was 312 grams, which reflects the removal of moisture and loss of volatile compounds that occurred during the pulsed steam purging process.

[0244] Example 3B: Low-pressure pulse steam treatment of sugarcane bagasse after ion extraction This experiment followed the same procedure as in Example 3A, but used bagasse that had previously undergone wet plasma and microbubble ion extraction treatment according to Examples 2A and 2B. The bagasse after ion extraction was then subjected to low-pressure pulsed steam treatment under the same conditions, namely 7 bar pressure, 5-second “on” phase, 2-second “off” phase, 20-minute treatment time, and 2.15 kW power consumption.

[0245] Significant differences were observed between steam treatment of licorice root without prior ion extraction (Example 3A) and steam treatment of sugarcane bagasse with prior ion extraction (Example 3B). Regarding odor characteristics, the licorice root in Example 3A released a stronger organic odor during steam treatment, while the sugarcane bagasse in Example 3B, after ion extraction, exhibited a significantly milder organic odor during steam treatment.

[0246] Regarding the properties of the steam condensate, the condensate obtained in Example 3A was a milky yellow solution with a conductivity of 3950 µS / cm; while the condensate obtained in Example 3B was a clear solution with a conductivity of 781 µS / cm. The final weight of the bagasse after ion extraction and steam treatment in Example 3B was 350 grams.

[0247] The aforementioned differences can be attributed to the prior ion extraction treatment. In Example 3A, the licorice root residue was not subjected to ion extraction, thus releasing a large number of mineral ions during steam treatment, resulting in a high condensate conductivity. In Example 3B, however, the sugarcane bagasse underwent ion extraction before steam treatment, removing most of the mineral ions. Consequently, the conductivity of the steam condensate was significantly lower, at only 781 µS / cm instead of 3950 µS / cm, demonstrating that ion extraction pretreatment effectively removes minerals that would otherwise be released during subsequent steam treatment.

[0248] These embodiments demonstrate that, firstly, low-pressure pulsed steam treatment at 7 bar can effectively improve the calorific value of biomass; secondly, pre-treatment with ion extraction can significantly reduce the mineral content released during subsequent steam treatment; and thirdly, combining ion extraction with steam treatment can produce biomass materials with better fuel performance and a cleaner processing method.

[0249] Example 4A: Steam generation efficiency of feedwater treatment using plasma A comparative test was conducted to evaluate the difference in steam generation efficiency between wet plasma-treated feedwater and untreated distilled water.

[0250] In the control test, 1,200 ml of distilled water was added to the water tank of the steam generator. The steam generator ran continuously at a constant power of 2,150 W for 15 minutes. After the test, 350 ml of water remained in the tank, so a total of 850 ml of water was converted into steam.

[0251] The test was then repeated under the same conditions using 1,200 ml of feedwater treated with wet plasma. The steam generator was also run at 2,150 W for 15 minutes. After the test, 285 ml of water remained, for a total of 915 ml of water was converted into steam.

[0252] The results showed that, under the same energy input conditions, plasma-treated feedwater could convert 915 ml of water into steam, while untreated distilled water could only convert 850 ml, which means that the steam generation was increased by 7.65%. This indicates that plasma treatment can improve the steam conversion efficiency of boiler feedwater, which is believed to be because the plasma-treated water is in a dehydrated and electron-rich state.

[0253] Example 4B: Low electromagnetic wave treatment of lignin A comparative test was conducted to evaluate the effect of low electromagnetic wave treatment on lignin bonding properties.

[0254] Two lignin samples, each weighing 200 grams, were prepared for the experiment. One sample underwent 30 minutes of low electromagnetic wave treatment with an energy input of 15.6 W and a total energy consumption of 7.8 Wh; the other sample remained untreated as a control. Subsequently, both samples were heated in an oven at 180°C for 15 minutes to simulate granulation conditions. A typical woody odor was observed during the heating process.

[0255] The bond strength of the two groups of samples was evaluated by tensile testing according to ASTM standard procedures. The test samples were prepared under controlled temperature and pressure conditions using a lignin sample bonded to a substrate.

[0256] The results showed that lignin treated with low electromagnetic waves had higher bonding strength compared with the untreated lignin control group. The 30-minute low electromagnetic wave treatment improved the adhesion properties of lignin, confirming that electromagnetic activation can enhance the effectiveness of lignin as a natural binder in the production of bioparticles.

[0257] This example demonstrates that low electromagnetic wave treatment can activate lignin molecules, improving their binding properties in granulation applications without the need for chemical modification or additional additives.

[0258] Example 5: Extraction of ions from empty palm fruit bunches of fiber An experiment was conducted to demonstrate the effectiveness of wet plasma and microbubble ion extraction methods in treating empty palm fruit bunch fibers.

[0259] The experiment used 750 grams of empty fruit bunch fiber and 2.2 liters of tap water as the washing medium. Ion extraction was performed using pulsed plasma method and a nascent oxygen microbubble generator, with a processing time of 15 minutes and a total electrical power input of 439 W.

[0260] Analysis of the washing liquid before and after treatment revealed that the conductivity increased from 120 µS / cm in the initial tap water to 5,100 µS / cm, or 5.1 mS / cm, after treatment, indicating that a large number of mineral ions were extracted from the fiber.

[0261] Further laboratory analysis showed that the concentration of potassium ions (K⁺) in the treated washing solution increased to 1550 ppm, and the concentration of phosphate ions (PO₄³⁻) increased to 93.9 ppm. The 42.5-fold increase in conductivity and the significant rise in the concentration of key nutrient ions confirm that this method can effectively extract minerals from empty fruit bunches of fiber.

[0262] The empty fruit bunch fibers after ion extraction were dried and ground into powder, which was then used to make brown bio-granules. After calorific value testing, the granules achieved a calorific value of 20.08 MJ / kg, which is significantly higher than that of bio-granules made from untreated empty fruit bunch fibers.

[0263] This embodiment demonstrates that the wet plasma and microbubble ion extraction method is suitable for processing palm oil hollow fruit bunch fiber, a widely existing agricultural waste material. The process successfully extracts mineral ions, particularly potassium and phosphate ions, which can be recovered as valuable agricultural nutrients. The ion-extracted fiber can be used to produce biomass pellets with higher calorific value, proving that the invention is applicable to a variety of different types of fibrous agricultural biomass feedstocks.

[0264] Example 6: Extraction of ions from water hyacinth stem material A control experiment was conducted to demonstrate the ion extraction capability of the method disclosed herein when treating water hyacinth (Eichhornia crassipes) stem material. In this embodiment, approximately 980 grams of water hyacinth stems were added to 17 liters of tap water to form a test solution. The test solution was then treated with the method disclosed herein for 45 minutes at a rated power of 345 W.

[0265] After treatment, the conductivity of the resulting solution increased significantly from the initial 120 μS / cm to 6,553 μS / cm. This significant increase in conductivity indicates, and is consistent with, the following conclusion: the method disclosed herein has successfully extracted and transferred ionic species from water hyacinth stem material into the surrounding aqueous phase.

[0266] This observation was further confirmed and verified by independent laboratory analysis. Specifically, the potassium ion (K⁺) concentration increased from 0 ppm in untreated tap water to 1,774 ppm in the treated extract, thus demonstrating that the method disclosed herein can effectively promote the migration of ionic components in the biomass matrix into the aqueous phase.

[0267] After ion extraction, the remaining water hyacinth stem material was recovered and dried in an air dryer for 4 hours. The dried material was then pulverized and ground into granular powder, which was then granulated into approximately 500 grams of bio-particles.

[0268] The above description is merely illustrative and should not be construed as limiting the invention. Although exemplary embodiments of the invention have been described, those skilled in the art will readily understand that many modifications can be made to these exemplary embodiments without substantially departing from the novel teachings and advantages of the invention. Therefore, all such modifications should be included within the scope of protection of the invention, defined by the claims and including their equivalents.

Claims

1. A method for producing biomass pellet fuel from agricultural waste biomass, comprising: a) Provide agricultural waste biomass containing more than 20% fiber by weight; b) Mechanically pulverize the biomass to a uniform size of 10 to 15 mm; c) The biomass is placed in a treatment tank containing washing water activated by wet plasma and microbubbles for ion extraction treatment to remove alkali metals, alkaline earth metals and mineral contaminants. d) The ion-extracted biomass is transferred to a low-pressure steam purge chamber; e) Under fuzzy logic control, the biomass is subjected to pulsating steam treatment at a pressure of less than 16 bar, wherein the pulsating steam is applied at a frequency of 10 Hz to 50 Hz. f) Maintain the biomass at a constant pressure of 13 to 16 bar for 2 to 10 minutes; g) Rapidly depressurize the purge chamber from the constant pressure to approximately 1 bar within 10 to 25 seconds to induce carbon chain rearrangement; h) The steam-treated biomass is dried to a moisture content of 7% to 14% by weight; as well as i) The dried biomass is pelletized to form bioparticle fuel.

2. The method according to claim 1, further comprising: a) The dried biomass is mixed with supplemental lignin, wherein the amount of supplemental lignin added is 10% to 20% of the dry weight of the biomass; b) The biomass-lignin mixture is placed in a processing chamber for low electromagnetic wave treatment; c) Electromagnetic waves with a frequency of 10 kHz to 10 MHz are generated using ferrite coil inductors disposed around the processing cavity. d) Applying pulsed electromagnetic waves to the biomass-lignin mixture to activate the lignin; and e) While the lignin remains in an activated state, the electromagnetically treated biomass-lignin mixture is granulated.

3. A simplified method for producing biomass pellet fuel from agricultural waste biomass, comprising: a) Provide agricultural waste biomass containing more than 20% fiber by weight; b) Mechanically pulverize the biomass to a uniform size of 10 to 15 mm; c) The biomass is placed in a treatment tank containing washing water activated by wet plasma and microbubbles for ion extraction treatment to remove alkali metals, alkaline earth metals and mineral contaminants. d) Separate mineral ions from the washing water and recover the ions as solid byproducts; e) The treated washing water is recycled back to the treatment tank; f) Without intermediate steam purging, the ion-extracted biomass is directly dried to a moisture content of 7% to 14% by weight. as well as g) Pelletize the dried biomass to form bioparticle fuel.

4. An apparatus for producing biomass pellet fuel from agricultural waste biomass, comprising: a) An ion extraction tank for containing biomass and washing water; b) A wet plasma and microbubble generator connected to the ion extraction cell; c) A plasma emitter made of multi-oxide composite material, disposed in or adjacent to the ion extraction cell; d) An air diffuser installed in the ion extraction cell to generate microbubbles; e) A low-pressure steam purge chamber configured to operate at pressures below 16 bar; f) A steam nozzle with a special geometry for distributing a pulsating steam flow within the purge chamber; g) A fuzzy logic controller integrated into a programmable logic controller for regulating pulsating steam flow at frequencies from 10 Hz to 50 Hz; h) A quick-release valve configured to depressurize the purge chamber from 13 to 16 bar to 1 bar within 10 to 25 seconds; i) A drying unit for reducing the moisture content of biomass; and j) A pelletizing unit for producing biomass pellets from dried biomass.

5. The method according to claim 1, wherein the wet plasma and microbubble generator activate the washing water through plasma discharge, wherein the plasma discharge generates reactive oxygen species, ultraviolet radiation, local heating, and an electrochemical potential gradient.

6. The method according to claim 1, wherein the ion extraction treatment is carried out in a liquid-biomass ratio of 5:1 to 15:1 by weight for a duration of 15 to 60 minutes.

7. The method of claim 1, wherein the plasma emitter is made of a multi-oxide composite material, the composite material comprising one or more metal oxides selected from the group consisting of titanium dioxide, zirconium dioxide and aluminum oxide.

8. The method of claim 1, further comprising recovering condensate from the steam purge chamber and introducing the condensate into an ion separation system to recover mineral salts.

9. The method according to claim 1, wherein the pulsating steam treatment induces cellulose fiber rearrangement, partial hydrolysis of hemicellulose, and formation of microcracks within the biomass structure.

10. The method of claim 1, wherein the steam treatment is provided by a fire-tube boiler operating at a pressure below 16 bar, thereby reducing scaling in the circulating piping system.

11. The method of claim 2, wherein the ferrite coil inductors are arranged in a plurality of rings or arrays around the processing cavity to form a uniform electromagnetic field distribution.

12. The method of claim 2, wherein the low electromagnetic wave processing operates in a frequency range of 50 kHz to 1 MHz and a field strength of 100 V / m to 10,000 V / m.

13. The method of claim 2, wherein the pulsating electromagnetic wave is characterized in that it is applied to the biomass-lignin mixture at a pulse frequency of 1 Hz to 100 Hz.

14. The method according to claim 2, wherein the supplementary lignin is selected from the group consisting of bovine lignin, lignin sulfonate, organic solvent-derived lignin, hydrolyzed lignin, and pyrolytically derived lignin.

15. The method of claim 2, wherein the produced bioparticles have a calorific value of 18 to 21 MJ / kg and a bulk density of 650 to 800 kg / m³.

16. The method of claim 3, further comprising using the recovered wash water as an agricultural nutrient solution, wherein the wash water contains nitrogen, phosphorus and potassium ions extracted from the biomass.

17. The method according to claim 3, wherein the ion-extracted biomass is directly transferred from the ion extraction tank to the drying unit, bypassing steam purging treatment, to produce biomass pellets with a calorific value of 16 to 18 MJ / kg.

18. The method of claim 1, wherein the drying is carried out in a multi-layer drying unit, using heated air at 100°C to 180°C applied in a counter-current manner.

19. The method according to claim 1, wherein the agricultural waste biomass includes sugarcane bagasse, giant reed grass, lemongrass, oil palm fruit branches, fruit plant stems, water hyacinth stems, and sawdust.

20. The apparatus according to claim 4, wherein the agricultural waste biomass includes sugarcane bagasse, giant reed, lemongrass, oil palm branches, fruit plant stems, water hyacinth stems, and sawdust.

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