Composite components from anaerobic digested fibrous materials
Inventors
Dvorak, Stephen W. • Hunt, John F.
Assignees
US Department of Agriculture USDA • DVO Inc
Publication Number
US-10731190-B2
Publication Date
2020-08-04
Expiration Date
2029-10-02
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Abstract
The invention relates to composite components and methods of producing composite components. In yet another embodiment, the present invention relates to a method of producing a composite component using anaerobically digested biomass. In still yet another embodiment, the method further comprises using liquid effluent from the digester. In still yet another embodiment, the method further comprises wet-mat forming and cold pressing the anaerobically digested biomass and wet-mat drying under heat and pressure.
Core Innovation
The invention relates to composite components and methods of producing composite components using anaerobically digested biomass derived from waste fibrous material. The method includes digesting waste fibrous material in an anaerobic digester to produce anaerobic digested biomass which is refined to yield fibers with lower carbohydrate content and increased cellulose and lignin content. These composite components can be produced without added chemical substances such as resins, waxes, or earthworms, relying on natural fiber-to-fiber bonding.
The method further involves wet-mat forming and cold pressing the anaerobic digested biomass, optionally combined with liquid effluent from the digester, followed by wet-mat drying under heat and pressure. The liquid effluent is protein-rich and enhances fiber-to-fiber bonding by acting as a natural resin after denaturation via heat during drying.
The process allows for controlled digestion parameters to optimize the composition of the digested biomass, yielding products with reduced carbohydrate content, increased lignin and cellulose content, improved water repellency, and better resistance to mold and biological attack. The composite components can be shaped into various sizes and forms, produced with fiber processing at various stages, and can be combined with other cellulosic fibers or cement to form composite materials with desirable strength and durability.
Claims Coverage
The patent includes three independent claims describing methods for producing composite components using anaerobic digested biomass and liquid effluent. The main inventive features revolve around processing steps, material compositions, and treatment conditions to produce fiber-based composites with enhanced properties.
Processing of anaerobic digested biomass and liquid effluent to form composite compositions
A method involving separating anaerobically digested waste material into digested biomass and liquid effluent, processing the biomass to break down fibers and fiber bundles, mixing the processed biomass with liquid effluent to form a composition, followed by wet-mat forming, cold-pressing, and drying the wet-mat to produce a composite component.
Use of cellulosic fibers with digested biomass compositions
Incorporating cellulosic fibers such as recycled paper, paper pulp, or old corrugated containers into the composition mixed with digested biomass and liquid effluent to enhance properties of the wet-mat formed composite components.
Control of wet-mat forming and drying parameters
Wet-mat forming employing mechanical pressure to remove free liquid and achieve moisture content about 50-65%. Drying is performed at temperatures ranging from 380° to 420° F and pressures from 60 to 1000 psi to promote protein denaturation and fiber-to-fiber bonding, enabling strong composite formation.
The claims collectively cover methods for producing composite components by processing anaerobically digested biomass combined with liquid effluent and optionally other fibers, employing wet-mat forming, cold-pressing, and controlled heat and pressure drying to yield composites with improved fiber bonding and material performance.
Stated Advantages
Composite components are produced without the need for added chemical substances like resins, waxes, or earthworms due to natural protein-based bonding.
Reduced carbohydrate content in fibers results in hydrophobic fibers, enhancing water repellency and dimensional stability, leading to less warping.
Increased lignin and cellulose content improves strength, stiffness, and durability of the composite components.
Protein denaturation during drying enhances fiber-to-fiber and fiber-to-effluent bonding, improving panel performance.
Composite materials show higher resistance to mold, fungal, and bacterial attack.
Documented Applications
Use of composite components as animal bedding, fertilizer, or compost derived from anaerobic digested biomass.
Production of fiber/cement composite panels for building trades, utilizing digested biomass as filler to improve cement curing.
Manufacture of shaped or sized composite panels for construction or industrial applications with improved water resistance and strength.
Conversion of livestock waste fibrous materials into value-added composite products, providing an outlet alternative to bedding or land application.
Use of digested biomass and effluent for producing composite components combined with recycled paper and other cellulosic fibers.
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