Description:Field of the Invention:
The present invention relates to sustainable manufacturing processes, specifically focusing on the production of compressed structural fiberboard using agricultural stubble as the primary raw material, incorporating microbial and earthworm treatments.

Background of the Invention:
The fiberboard manufacturing field has traditionally relied on wood-derived materials, a practice that significantly contributes to deforestation and environmental strain. With the escalating concerns about environmental degradation and the depletion of natural resources, there has been a pressing need to explore alternative raw materials for producing fiberboards. In this context, using agricultural by-products, such as stubble, emerges as a sustainable and eco-friendly alternative.

Stubble, the agricultural residue remaining after the harvesting of crops, represents a substantial but underutilized resource. In many parts of the world, including India, this stubble is often burned, leading to air pollution and the loss of a potentially valuable material resource. The conversion of this agricultural waste into useful products helps in waste management and contributes to the economic upliftment of farming communities.

However, using stubble to produce compressed structural fiberboard faces several technical challenges. The primary issues revolve around the inherent properties of stubble, which differ significantly from conventional wood materials. Stubble fibres are often shorter and less dense, producing finished products with inferior structural and mechanical properties. Furthermore, the high variability in the composition of stubble, depending on the type of crop, harvest method, and other factors, adds to the complexity of developing a standardized production process.

To overcome these challenges, recent research has focused on enhancing the properties of stubble for use in fiberboard manufacturing. One promising approach is the biological treatment of stubble using specific microorganisms to break down complex plant materials, thus improving the binding and structural properties of the resulting fiberboard. Additionally, the incorporation of earthworms in the process, known for their ability to enrich and stabilize organic materials, presents an innovative method to enhance the quality of the fiberboard further.

Despite these advancements, there remains a gap in the existing technologies for an efficient, scalable, and eco-friendly process to convert stubble into high-quality compressed structural fiberboard. The present invention addresses this gap by introducing a novel method and apparatus that not only makes effective use of agricultural stubble but also improves the environmental footprint of the fiberboard manufacturing process.

Objective of the Invention:
The primary objective of the present invention is to provide an eco-friendly and sustainable method for producing compressed structural fiberboard from agricultural stubble. This method aims to effectively utilize agricultural waste, specifically stubble, thereby reducing environmental pollution and promoting waste recycling.

Another objective of the invention is to integrate advanced microbial and earthworm treatments in the processing of agricultural stubble. This integration is designed to enhance the decomposition and transformation of stubble into a suitable raw material for fiberboard production, thereby improving the material properties and quality of the final product.

It is also an objective of this invention to develop an apparatus specifically designed to carry out the aforementioned method. This apparatus is intended to efficiently handle each stage of the fiberboard production process, from raw material collection and treatment to extrusion and final product formation, ensuring consistency and high quality in the fiberboards produced.

Furthermore, the invention aims to introduce a process that is not only environmentally sustainable but also economically viable. By employing natural resin binders and implementing a recycling step within the production process, the invention seeks to minimize the use of synthetic chemicals and reduce manufacturing costs.

An additional objective is to facilitate ease of operation and scalability in the production of compressed structural fiberboard. The method and apparatus are designed to be adaptable to various scales of production, catering to both small-scale and large-scale manufacturing needs.

Lastly, the invention aims to contribute to the broader goals of sustainable manufacturing practices and the promotion of circular economy principles in the agricultural and industrial sectors.

The above and other objectives of the present invention are achieved according to the following embodiments of the present invention. The disclosed embodiments exemplify the preferred and best mode of the invention and should not be construed as limiting the scope of the invention.

Summary of the Invention:

Accordingly, the present invention provides a method for making compressed structural fiberboard from stubble, comprising: collecting a stubble from agricultural fields, wherein the stubble predominantly consists of crop residues post-harvest;
mixing the stubble with wheat straw in a weight ratio ranging from 100:0.5 to 100:1.0 so that the Carbon/Nitrogen (C/N) is in a ratio of 25-30;
treating the mixture with a strain of microorganisms, including but not limited to EM bacteria, ferment microbial inoculum, or VT microbial inoculum, wherein the microorganisms have a viable count of at least 2 * 10^9 Cfu/g and are used in an amount of 0.3%-0.8% of the mixture's weight;
adding the compost inoculant during a quick fermentation stage, maintaining the mixture's central point temperature below 35?;
inoculating with earthworms in an amount of 200-300 worms per cubic meter of material during the after-ripening stage;
processing the treated mixture, involving drying to reduce moisture content to 50%-60% and grinding to a length of 0.5-1.5 cm;
mixing the processed mixture with a binding agent;
feeding the mixture into an extruder equipped with a cyclic ramp operated by electric linear actuators for consistent compaction, forming a continuous structural fiberboard; extruding the mixture through a die to form fiberboard with specified thickness and width;
heating the extruded fiberboard to a temperature sufficient to activate the binding agent; cooling the heated fiberboard to set its shape and dimensions, involving a cooling period within a range of 20-60 minutes; and
cutting the continuous fiberboard into predetermined lengths using a cutting mechanism.

In another aspect of the present invention, the binding agent is a natural resin, synthetic adhesive, or a combination thereof, used in proportions ranging from 5% to 20% of the total mixture weight.

In another aspect of the present invention, wherein the collected stubble includes residues from crop such as rice, wheat, or barley/

In another aspect of the present invention, the method further comprises a post-extrusion surface treatment step to enhance physical properties like water resistance or fire retardancy.

In another aspect of the present invention, in the recycling step up to 30% of the produced fiberboard is reused as raw material for subsequent production cycles.

In another aspect of the present invention, the electric linear actuators of the extruder operate with a force range of 10-30 kN to ensure uniform pressure during the extrusion process.

In another aspect of the present invention, further comprises an automated control system, specifically a programmable logic controller (PLC), to regulate the processing parameters and ensure consistent product quality.

In another aspect of the present invention, the extrusion process involves maintaining an extrusion temperature within the range of 140-180?.

In another aspect of the present invention, the stubble and wheat straw mixture undergoes a microbial treatment phase lasting between 7-14 days.

In yet another aspect the present invention provide an apparatus for preparing compressed structural fiberboard,
comprising: a collection system for collecting stubble and wheat straw;
a microbial and earthworm inoculation unit with temperature control capabilities; a processing unit for drying and grinding;
an extruder assembly with specified mechanical and thermal controls;
a heating and cooling unit with predefined temperature and time settings; a cutting unit with adjustable size settings;
an integrated control system for overseeing and adjusting the operational parameters.

Detailed Description of the Invention:
The following is a detailed description of implementations of the present disclosure depicted in the accompanying experiments. The implementations and embodiments are in such detail as to clearly communicate the disclosure. However, the amount of detail offered is not intended to limit the implementations and embodiments but it is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure. While aspects of described a synergistic herbicidal formulation and method thereof are described further in the context of the following experimental details.

Various terms as used herein in the invention is not defined and it should be given the broadest definition persons in the pertinent art have given that term as reflected in printed publications and issued patents at the time of filing.

In the description herein, numerous specific details are set forth in order to provide a thorough understanding of embodiments of the present invention. It will be apparent to one skilled in the art that embodiments of the present invention may be practiced without some of these specific details.

The present invention relates to an innovative and eco-friendly method for producing compressed structural fiberboard from agricultural stubble, integrating advanced microbial and earthworm treatments. This description elucidates each step of the process, focusing on specific parameters and examples to provide a comprehensive understanding of the invention.

Reference throughout this specification to “one embodiment” or “an embodiment” means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, the appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” include plural referents unless the content clearly dictates otherwise. It should also be noted that the term “or” is generally employed in its sense including “and/or” unless the content clearly dictates otherwise.

The embodiments are in such detail as to clearly communicate the disclosure. However, the amount of detail offered is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure as defined by the appended claims.

The present invention relates to an eco-friendly method for producing compressed structural fiberboard from agricultural stubble, integrating advanced microbial and earthworm treatments. This description elucidates each step of the process, focusing on specific parameters and examples to provide a comprehensive understanding of the invention.

Collection and Preparation of Stubble:
Stubble from crops like rice, wheat, or barley is collected post-harvest. The stubble, characterized by its fibrous nature and variable composition, is then mixed with wheat straw. The

mixing ratio is critical and is maintained between 100:0.5 to 100:1.0, aiming to achieve an optimal Carbon/Nitrogen (C/N) ratio of 25-30, which is essential for the subsequent microbial action.

Biological Treatment:
The mixed stubble undergoes a two-stage biological treatment. Initially, it is treated with microorganisms, selected based on their efficiency in breaking down cellulose and lignin. Examples include EM bacteria, ferment microbial inoculum, or VT microbial inoculum, with a viable count of at least 2 * 10^9 Cfu/g. These microorganisms are applied in a proportion ranging from 0.3% to 0.8% of the mixture's total weight.

During the quick fermentation stage, the mixture's central temperature is strictly controlled below 35?, typically lasting 7-14 days. This controlled environment is pivotal for optimal microbial activity.

The after-ripening stage involves the inoculation of earthworms, at a density of 200-300 per cubic meter of material. The earthworms play a crucial role in enhancing the bioconversion process.

Processing of Treated Mixture:
Post-treatment, the stubble mixture is processed to achieve uniformity for extrusion. This involves drying the material to achieve moisture content between 50%-60% and grinding it to a size of 0.5-1.5 cm.

Addition of Binding Agent and Extrusion Process:
A binding agent, such as a natural resin or synthetic adhesive, is then mixed with the processed stubble. The binding agent constitutes 5% to 20% of the total mixture weight. This proportion is carefully calculated to ensure adequate binding without compromising the material's integrity.
The mixture is fed into an extruder, where it is compressed into a continuous structural fiberboard. The extruder is equipped with a cyclic ram, powered by electric linear actuators that apply a force ranging from 10-30 kN. This ensures uniform compaction and consistency in the fiberboard's density. The extrusion temperature is maintained between 140-180?.
Final Product Formation:
Post-extrusion, the continuous fiberboard undergoes a heating process, activating the binding agent, followed by a cooling period of 20-60 minutes to solidify and stabilize the board.

The fiberboard is then cut into predetermined lengths, according to market or application requirements, using precision cutting mechanisms.

Recycling and Surface Treatment:
The process incorporates a recycling step, wherein up to 30% of the produced fiberboard can be reintegrated as raw material, significantly enhancing the process's sustainability.

Optionally, the fiberboard undergoes surface treatments to enhance properties like water resistance or fire retardancy, depending on the end-use requirements.

Automated Control System:
An automated control system, specifically a Programmable Logic Controller (PLC), is integrated to regulate and monitor the process parameters. This system ensures that each phase of the manufacturing process adheres to the predefined standards, thus guaranteeing product consistency and quality.

Examples
As an illustrative example, using rice stubble with an EM bacterial strain applied at 0.5% of the total mixture weight, under a controlled temperature of 30? for 10 days, followed by 7 days of earthworm inoculation, has been found effective. The extrusion process at 160? with a 45- minute cooling period yields a high-quality fiberboard.

A lignin-derived resin as a binder at a 10% proportion has been found to provide excellent binding properties without compromising the board's structural integrity.

Example 1
One ton of rice stubble is collected from a farm post-harvest. This stubble is then mixed with 50 kg of wheat straw, achieving a ratio of 100:0.5, optimal for the desired C/N ratio.
Example 2 Biological Treatment
Microbial Treatment Example: A specific batch of EM bacteria is selected, known for its high cellulase activity. For a 1.05-ton mixture of stubble and wheat straw, 3 kg of EM bacteria inoculum (0.3% of the mixture's weight) with a viability of 2.5 * 10^9 Cfu/g is uniformly spread over the mixture.

Temperature Control Example: During the quick fermentation stage, the mixture is placed in a controlled environment where the temperature is carefully maintained at 32? for 10 days.

Earthworm Inoculation Example: Post the microbial treatment, 250 earthworms per cubic meter are introduced into the mixture. For a 1.05-ton batch, approximately 3000 earthworms are used. This stage lasts for an additional 7 days.

Example 3
Processing of Treated Mixture:

The treated mixture is then dried in a rotary dryer until it reaches a moisture content of 55%. Subsequently, it is passed through a grinder where the particle size is reduced to an average of 1 cm.

Example 4

Addition of Binding Agent and Extrusion Process:
Binding Agent: A natural resin derived from pine trees, known for its adhesive properties, is chosen as the binding agent. For the 1.05-ton batch, 105 kg (10% of the mixture weight) of this resin is thoroughly mixed into the ground stubble.

The mixture is then fed into an extruder that applies a consistent force of 20 kN. The extruder operates at a temperature of 160?, ensuring optimal binding and formation of the fiberboard.
Example 5
Final Product Formation:
Heating and Cooling: After extrusion, the fiberboard is passed through a heating tunnel where it is heated at 160? for 30 minutes to activate the resin fully. It is then cooled in a cooling chamber for 40 minutes to solidify and stabilize.

Example 6
Recycling and Surface Treatment:
From the produced batch, 300 kg of fiberboard is shredded and mixed back into the initial mixture for the next batch, effectively recycling 30% of the output.

Surface Treatment: The final fiberboards are coated with a water-resistant polymer layer to enhance their durability in humid conditions. This coating is applied in a spray booth where the boards are uniformly covered and then dried.

Example 7
Automated Control System:
A PLC system is programmed to monitor the temperature, humidity, and processing time at each stage. It adjusts the extruder's speed and the temperature in the heating tunnel based on real-time data to ensure consistent quality.

Example 8
The apparatus designed for producing compressed structural fiberboard from agricultural stubble using microbial and earthworm treatment is tailored to handle the specific requirements of each stage of the process. Here are more detailed descriptions of the key components of the apparatus.

Collection System:

A specialized collection system is implemented for gathering agricultural stubble. This system includes a series of conveyors and hoppers equipped with sensors to ensure the correct ratio of stubble to wheat straw. The system is capable of handling up to several tons of material per day. In the present invention, a conveyor with adjustable speed settings transports 1 ton of rice stubble and 50 kg of wheat straw to the mixing area.
Mixing and Treatment Unit:
Microbial Treatment Subsystem: This unit is equipped with a spreader mechanism for evenly distributing the microbial inoculant over the stubble and wheat straw mixture. It includes a temperature-controlled enclosure to maintain the mixture at the desired fermentation temperature.

Earthworm Inoculation Subsystem: Following microbial treatment, the earthworm inoculation subsystem introduces earthworms into the mixture. This subsystem is designed with perforated surfaces to allow for aeration and movement of earthworms throughout the material.

Drying and Grinding Unit:
Drying Subsystem: The drying subsystem consists of a rotary dryer capable of reducing the moisture content of the mixture to the targeted range (50%-60%). This dryer is equipped with moisture sensors and automated temperature control.

Grinding Subsystem: Post-drying, the material is transferred to a grinding subsystem, which includes industrial-grade mills or grinders. These are calibrated to achieve a uniform particle size of 0.5-1.5 cm.

Extrusion Assembly:
The extruder is the core component of the apparatus. It is equipped with a high-capacity, electrically driven cyclic ram, capable of exerting a force range of 10-30 kN. The extruder barrel is temperature-controlled, with the capability to maintain a consistent extrusion temperature of 140-180?.

The extruder is set to operate at 160? and applies a force of 20 kN to compress the mixture into the fiberboard.

Heating and Cooling Unit:
Heating Subsystem: This includes a tunnel-like structure where the extruded fiberboard is heated uniformly. The heating system is capable of reaching up to 200?, although for this process, it is set at 160?.
Cooling Subsystem: Following the heating phase, the cooling subsystem uses fans and ambient air flow to bring down the temperature of the fiberboard within 40 minutes, ensuring the board sets properly.

Cutting and Finishing Unit:

Cutting Subsystem: The cutting subsystem includes automated saws or blades that are adjustable for cutting the continuous fiberboard into predetermined lengths.

Finishing Subsystem: Optionally, a finishing subsystem can be included for surface treatments such as coating or sealing, depending on the final application of the fiberboard.

Control System:
An integrated control system, usually a Programmable Logic Controller (PLC), is programmed to monitor and adjust the operational parameters of the entire apparatus. This system includes various sensors and control mechanisms for real-time adjustments and process optimization.

Recycling Subsystem:

A section of the apparatus is dedicated to recycling. It includes shredding equipment to process a portion of the produced fiberboard back into the initial mixture.

While the invention is amenable to various modifications and alternative forms, some embodiments have been illustrated by way of example in the experiments and are described in detail above. The intention, however, is not to limit the invention by those examples and the invention is intended to cover all modifications, equivalents, and alternatives to the embodiments described in this specification.

The embodiments in the specification are described in a progressive manner and focus of description in each embodiment is the difference from other embodiments. For same or similar parts of each embodiment, reference may be made to each other.

It will be appreciated by those skilled in the art that the above description was in respect of preferred embodiments and that various alterations and modifications are possible within the broad scope of the appended claims without departing from the spirit of the invention with the necessary modifications.

Based on the description of disclosed embodiments, persons skilled in the art can implement or apply the present disclosure. Various modifications of the embodiments are apparent to persons skilled in the art, and general principles defined in the specification can be implemented in other embodiments without departing from the spirit or scope of the present disclosure. Therefore, the present disclosure is not limited to the embodiments in the specification but intends to cover the most extensive scope consistent with the principle and the novel features disclosed in the specification.
, Claims:We Claim:

1. A method for making compressed structural fiberboard from stubble, comprising: collecting a stubble from agricultural fields, wherein the stubble predominantly consists of crop residues post-harvest;
mixing the stubble with wheat straw in a weight ratio ranging from 100:0.5 to 100:1.0 so that the Carbon/Nitrogen (C/N) is in a ratio of 25-30;
treating the mixture with a strain of microorganisms, including but not limited to EM bacteria, ferment microbial inoculum, or VT microbial inoculum, wherein the microorganisms have a viable count of at least 2 * 10^9 Cfu/g and are used in an amount of 0.3%-0.8% of the mixture's weight;
adding the compost inoculant during a quick fermentation stage, maintaining the mixture's central point temperature below 35?;
inoculating with earthworms in an amount of 200-300 worms per cubic meter of material during the after-ripening stage;
processing the treated mixture, involving drying to reduce moisture content to 50%-60% and grinding to a length of 0.5-1.5 cm;
mixing the processed mixture with a binding agent;
feeding the mixture into an extruder equipped with a cyclic ramp operated by electric linear actuators for consistent compaction, forming a continuous structural fiberboard; extruding the mixture through a die to form fiberboard with specified thickness and width;
heating the extruded fiberboard to a temperature sufficient to activate the binding agent; cooling the heated fiberboard to set its shape and dimensions, involving a cooling period within a range of 20-60 minutes; and
cutting the continuous fiberboard into predetermined lengths using a cutting mechanism.

2. The method as claimed in claim 1, wherein the collected stubble includes residues from crops such as rice, wheat, or barley.

3. The method as claimed in claim 1, further comprising a post-extrusion surface treatment step to enhance physical properties like water resistance or fire retardancy.

4. The method as claimed in claim 1, where the binding agent is a natural resin, synthetic adhesive, or a combination thereof, used in proportions ranging from 5% to 20% of the total mixture weight.

5. The method as claimed in claim 1, wherein in the recycling step up to 30% of the produced fiberboard is reused as raw material for subsequent production cycles.

6. The method as claimed in claim 1, wherein the electric linear actuators of the extruder operate with a force range of 10-30 kN to ensure uniform pressure during the extrusion process.

7. The method as claimed in claim 1, wherein further comprises an automated control system, specifically a programmable logic controller (PLC), to regulate the processing parameters and ensure consistent product quality.

8. The method as claimed in claim 1, wherein the extrusion process involves maintaining an extrusion temperature within the range of 140-180?.

9. The method as claimed in claim 1, wherein the stubble and wheat straw mixture undergoes a microbial treatment phase lasting between 7-14 days.

10. An apparatus for compressed structural fiberboard as claimed in claims 1-9, comprising: a collection system for collecting stubble and wheat straw;
a microbial and earthworm inoculation unit with temperature control capabilities; a processing unit for drying and grinding;
an extruder assembly with specified mechanical and thermal controls;
a heating and cooling unit with predefined temperature and time settings; a cutting unit with adjustable size settings;
an integrated control system for overseeing and adjusting the operational parameters.

Dated this 20th Day of January 2024