Method for producing reactive biomass and products thereof

Abstract

According to one exemplary aspect of the present invention, there is provided a method of converting plant material into a curable biomass by reactive extrusion in a series of extrusion modules, in which the carbohydrate compounds of the plant material are exposed.

Description

Technical Field

[0001] The present invention relates to a method for producing a recyclable and biodegradable solid biocomposite and a wet substance from a plant material in which the whole is contained in a biocomposite without prior separation of components from the plant.

Background Art

[0002] Amine derivatization in extrusion is described in Finnish Patent Application No. 129257. Cellulose, its derivatives and mixtures thereof form amides with amine reagents. This is a chemical condensation reaction. In the condensation reaction, it is necessary to remove excess water during drying. After the reaction, the carbohydrate amide compound solidifies and all components have the same structure. Therefore, separation of components such as cellulose and lignin is not required. Separation of such components requires a lot of energy, water, and a lot of machinery and takes time, so this technology is beneficial. Amine derivatization does not require non-renewable materials derived from petroleum. The final biocomposite contains more than 80% of the original plant raw material. As a result, this type of biocomposite production is excellent.

[0003] Amine derivatization with urea requires a temperature below 130°C, which is too low to efficiently expose carbohydrates in normal extrusion. In the amine reaction, it is also necessary to efficiently acidify the carbohydrates. High acidity has an adverse effect on extrusion. As a result, as shown in Finnish Patent Application No. 20185627, no strong structure is formed in amine derivatization.

[0004] A normal twin-screw extruder mixes the mass in a screw within a cylinder capable of heating and cooling. In the reaction zone, the mass is transferred through a reverse screw and the pressure increases. Finally, the mass is extruded out through a nozzle. A twin-screw extruder is used to mix bio materials and other components. The final biocomposite is shaped and dried in a downstream process after being processed by the extruder.

[0005] The extrusion applied to the amine derivatization is described in Finnish Patent Application No. 20185627. Since the twin-screw extruder has only one reaction zone, it is not the most efficient for shearing plant raw materials. It is difficult to maintain high temperature and high pressure in a twin-screw extruder. Furthermore, since a twin-screw extruder requires many pre-processes and downstream processes, the process is complex and restricted. For example, efficient pre-grinding of plant raw materials is required.

[0006] Therefore, there is a need for a novel method for producing recyclable and biodegradable solid biocomposites and wet substances from plant materials in which the whole is included in the biocomposite without prior separation of any components from the plant.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Patent Document 2

[0008] (Summary of the Invention) The present invention is defined by the features of the independent claims. Some specific embodiments are defined in the dependent claims.

[0009] According to one aspect of the present invention, there is provided a method for converting plant material into curable biomass by reactive extrusion comprising a series of extruder modules.

[0010] This aspect and other aspects are realized by the present invention as described and claimed below, together with their advantages over known solutions.

[0011] The method of the present invention is characterized mainly by what is described in the characterizing part of claim 1.

[0012] The present invention provides significant advantages. In this specification, reactive extrusion consists of a plurality of unit operations whose conditions can be controlled according to physical and reactive requirements. Planetary roller extrusion (PRE) is a mechanical option for reactive extrusion. In reactive extrusion, multiple modules of PRE function as continuous reaction zones with different conditions. Since PRE does not require extra water for material transfer, the reaction stream is solid. Despite using solid materials, PRE has excellent heat conduction, shearing, mixing, and grinding capabilities. Furthermore, the method of the present invention uses renewable materials, little energy, a small amount of water, and a small number of machines. The resulting products are recyclable and biodegradable. Therefore, even if the products are recycled in nature, they do not harm nature. Additionally, in the production of reactive biomass using the multi-axis screw extruder, no significant decomposition of carbohydrate polymers into monosaccharides occurs. Therefore, monosaccharides are not exposed to harsh extrusion conditions such as high temperatures. This phenomenon reduces the generation of harmful chemicals such as furfural and hydroxymethylfurfural.

[0013] Next, the present technology will be described in more detail with reference to specific embodiments.

[0014] (Embodiment) The present technology provides a method for manufacturing recyclable and biodegradable solid bio-composite objects and wet substances. These are manufactured from plant materials that are completely contained in the bio-composite without separating any components from the plants beforehand. The raw materials can be, for example, straw, hay, leaves, husks, and other by-products from a grain mill. The raw materials can also be selected from shredded cardboard, paper, sawdust, shredded cotton cloth, etc. The dried bio-objects can be perforated, polished, adhered, and painted. The wet substances function as biological adhesives (bio-adhesives). These can also function as fertilizers and soil improvers.

[0015] In this specification, the following definitions apply: Reactive Biomass: Reactive biomass that solidifies during drying or produces, for example, wet bioadhesives and fertilizers through reactive extrusion is produced. In some cases, it may be necessary to add acid to the mass before drying. More precisely, reactive biomass is a wet, reactive, and moldable fibrous mass produced using plasticizable renewable materials in a multi-screw extruder. All components of the blend are naturally decomposable natural polymers and do not contain petroleum-derived or fossil components. Mixing renewable urea or lignin into the reactive biomass and drying the mixture forms an irreversible hard chemical structure. Reactive biomass is reactive because the hemicellulose, cellulose, and lignin that are components of the pulp, as well as the added plasticizer, participate in the reaction with urea or lignin. Solidification: Reactive carbohydrates solidify through a chemical reaction when dried. Solidification co-cures all components of the mass. The resulting substance does not easily break down in water. Solid Bio-product Objects: Solid bio-product objects can be perforated, polished, adhered, and painted. Recyclability: The said substance can be ground and reused. Combustion that emits carbon dioxide can be avoided. Biodegradability: Through hydrolysis by cellulase, the said substance is biodegradable. Starch is easily hydrolyzed in nature. Lignin functions as natural lignin. Polyvinyl alcohol is gradually decomposed in nature as required.

Brief Description of the Drawings

[0016]

Figure 1

Figure 2

Modes for Carrying Out the Invention

[0017] The method of the present invention is based on the exposure of the carbohydrate compounds of the plant raw material in reactive extrusion. Thus, this functions as an active ingredient of the biocomposite. Optionally, the carbohydrate can be acidified. All major unit operations and reactions are carried out in one planetary roller extruder (PRE), and the final shaping and drying are carried out in downstream processes.

[0018] Dry fibers (optionally including starch), water, and a renewable CMC, for example, are added to the multi-screw extruder. CMC and starch plasticize the biomass and are later involved in the chemical reaction of the reactive biomass during drying. The plasticized biomass spreads easily within the multi-screw extruder, achieving a high vapor pressure, and as a result, high temperatures can be reached.

[0019] According to one embodiment, the method for converting plant material into curable biomass comprises providing an aqueous suspension comprising the plant material, feeding the suspension to a multi-screw extruder comprising a series of a plurality of extruder modules, optionally adding external carbohydrates to increase the viscosity of the suspension and improve the dough-like state, and in a series of the extruder modules, grinding and / or shearing the suspension at a temperature of at least 150°C to expose and / or release the carbohydrates and lignin of the plant material, and obtaining a wet and curable reactive biomass comprising the exposed carbohydrates and lignin. comprises at least.

[0020] In the multi-screw extrusion, the dry fibers are sufficiently wetted. The fibers are ground and mixed under the influence of mechanical force, heat, and pressure. The water content of the reactive biomass may be as low as about 40%. The fibers can be heated to over 200°C with an absolute vapor pressure exceeding 16 bar.

[0021] The multi - shaft screw extruder is more efficient than the twin - shaft screw extruder in terms of grinding, mixing, and heat transfer. Further, the multi - shaft screw extruder has more grinding blades and mixing blades and a larger effective surface area than a typical twin - shaft screw extruder where part of the screw only functions as a conveyor. Further, in the continuous module (within the reaction zone) of the multi - shaft screw extruder, many repetitive processes are carried out. The modules are separated by an exchangeable nozzle plate, and through this nozzle plate, the plant mass is pushed into the next module which can have different blades and conditions.

[0022] In continuous multi - shaft screw extrusion, as the pressure rises and the pulp density increases, light and airy fibers are compressed into piles. The wet reactive biomass is heavy and this contributes to the reaction and volume increase. However, the dried reactive biomass product is light and durable. Under extrusion conditions, a large amount of fibers pass through the continuous extruder, which is a phenomenon that becomes prominent when the humidity is low. Thus, the intensive technology of the present invention realizes an increase in capacity and an improvement in scalability with a device smaller than the devices disclosed in the prior art, which is surprising and beneficial.

[0023] According to one embodiment, the plant material includes annual and perennial plant materials such as straw, hay, leaves, by - products from grain crushers, and recycled materials such as shredded cardboard, paper, wood chips, shredded cotton cloth, shredded straw or oat husks. In this method, with one machine having a plurality of continuous reaction zones, the feed is finely ground, heat - treated, sheared, and mixed with other raw materials until the dry matter reaches 60%.

[0024] Reactive extrusion consists of multiple unit operations whose conditions are controlled according to physical conditions and reaction requirements. The planetary roller extruder (PRE) is a mechanical option for reactive extrusion. In reactive extrusion, the modules of the PRE function as continuous reaction zones with different conditions. Since the PRE does not require extra water for material transportation, the reaction stream is solid. Despite using solid materials, the PRE has excellent heat conduction, shearing, mixing, and grinding capabilities.

[0025] According to one embodiment, the multi - screw extruder is a planetary roller extruder (PRE). The PRE produces a homogeneous mass that forms a solid after drying. The solidification targets include all components of the PRE feed. The wet product can function as an adhesive. The solid can be perforated, polished, and painted. Also, by adding nitrogen, potassium, and / or phosphorus, it can also function as a fertilizer.

[0026] The PRE can process many raw materials derived from, for example, agriculture: straw, rice husks, crushed scraps; food industry: skins, feathers, chitin; forestry: fibers, lignin, wood; textile industry: used fabrics; bioplastics: packaging materials, and some recycled materials.

[0027] Physical processes that can occur in the PRE include, for example, efficient grinding, efficient heat transfer, efficient mixing, and repeatable shearing (hydrothermal treatment) under high temperature and high pressure under various conditions.

[0028] Chemical reactions that can occur in the PRE include, for example, chemical and biochemical hydrolysis, condensation, and polymerization.

[0029] In the PRE, bio - composites (objects, packaging materials, building materials), bio - fertilizers (soil improvers fortified with nitrogen, phosphorus, and minerals as required), bio - adhesives, and raw materials for efficient enzymatic hydrolysis (for example, raw materials for producing monosaccharides used in further processes) can be produced.

[0030] In one embodiment, the PRE exposes carbohydrates, which are cellulose and uronic acid-containing compounds from plants and recycled materials. The exposed carbohydrates react in a chemical condensation reaction to produce water. Through such reactions, an ester is formed with lignin or an amide is formed with an amine. Both reactions require the carbohydrates to be in an acidic stage. However, the amide reaction requires a higher degree of acidification. To advance the condensation reaction, removal of excess moisture that occurs during drying is necessary. The present invention is based on one PRE machine consisting of multiple modules that provide a number of continuous reaction zones, and then the mass is dried in an external machine.

[0031] In one embodiment, the PRE uses plant and recycled materials, such as shredded straw, water, and external materials such as carboxymethyl cellulose (CMC), kraft lignin, urea, etc., all of which are involved in the reaction. Other external materials are described in Finnish Patent Application No. 20185627. The first PRE module pulverizes the shredded straw. The next module heats, shears, and mixes the raw materials at a temperature exceeding 200°C. Carbohydrates are exposed by pulverization, high heat, and shearing under high pressure. In the last module, the solid stream is cooled and taken out as a fine and homogeneous mass. The external materials are added to the appropriate modules. For example, urea requires a temperature below 120 - 130°C.

[0032] According to one embodiment, the external carbohydrates are carboxymethyl cellulose (CMC), starch, or alginate.

[0033] According to yet another embodiment, external reactive carbohydrates such as CMC, starch, or alginate are added with the feed or after chopping the straw. CMC, such as other hydrocolloids, also acts as a viscosity enhancer in reactive extrusion. CMC forms dough even with finely chopped wheat straw. This dough causes a non-mechanical and controllable blockage in the end of the reactive extruder. This blockage allows the use of temperatures above 200 °C in the extruder, thereby generating a high vapor pressure. Without a controllable viscous substance, the high vapor pressure would be immediately released from the extruder. This release deprives most of the moisture, and the extruder completely blocks.

[0034] According to one embodiment, if the addition of an acid is required for the acidification of the carbohydrate, the addition is preferably done last or after the treatment in the extruder. Acids cause strong corrosion at high temperatures and some acids decompose under such conditions.

[0035] Finnish Patent Application No. 20185627 discloses an amide reaction and twin-screw extrusion. The method of the present invention has the following novel features compared to, for example, that disclosed in Finnish Patent Application No. 20185627: a) reactive extrusion by a plurality of consecutive reaction zones, b) exposing reactive carbohydrates from plants and recycled materials for a chemical condensation reaction, c) a chemical condensation reaction with lignin that does not require an amine, d) the ability to use high temperatures in reactive extrusion by using CMC, starch or alginate as reactive carbohydrates and as materials that generate viscosity, and e) processing the raw materials in one multi-screw device to provide a homogeneous biomass that is compressed into a mold.

[0036] In summary, the solid bio-composite and the wet substance are obtained by the following two chemical means: Ester reaction · Perform reactive extrusion of plants and recycled materials with, for example, CMC and kraft lignin (or polyvinyl alcohol); · Place in a mold and dry; Amide reaction ·Perform reaction extrusion of plants, recycled materials, CMC and urea (added under conditions of 120 - 130 °C); ·Acidify; ·Put into a mold and dry, and is produced by.

[0037] According to one embodiment, the production of monosaccharides from lignocellulose does not require an ester or amide reaction. Efficiently exposing reactive cellulose and hemicellulose in the PRE for the enzyme reaction is the most important feature.

[0038] Normally, fibers only act as fillers in biocomposites and do not chemically bond in biocomposites. In the method of the present invention, by continuously shearing and mixing at a high temperature exceeding 150 °C, a part of hemicellulose and cellulose is released, and this participates in the condensation reaction. The hemicellulose of straw is composed of arabinoglucuronxylan (1,6:1:16,6), which is partially soluble in hot water. The glass transition of lignin occurs at 150 - 180 °C, whereby a part of the lignin that fixes cellulose opens. The exposure of carbohydrates during extrusion depends on shear, temperature, pressure, carbohydrate concentration, and time. If the extrusion time is short, only a part of the carbohydrates is exposed, and the strength of the final structure is beneficially increased.

[0039] According to one embodiment, loose materials are difficult to extrude at a high temperature due to high vapor pressure. In loose materials, steam jets out from the extruder and all free water is taken away. The absolute vapor pressure at 200 °C is about 16 bar. As a result, the extruder becomes severely blocked. In the method of the present invention, CMC forms a viscous dough from loose materials and prevents the steam from jetting out from the extruder. CMC beneficially participates in the chemical reaction of carbohydrates.

[0040] According to one embodiment, the method includes at least partially filling a mold with the wet and curable reactive biomass obtained from the step of performing the grinding / shearing, and drying the biomass in the mold to produce a solid bio-composite.

[0041] According to one embodiment, the wet and curable reactive biomass is mixed with an amine reagent or lignin, formed, and dried to become a bio-composite.

[0042] According to one embodiment, the wet and curable reactive biomass is mixed with urea and dried to become a fertilizer or part of a fertilizer.

[0043] According to a further embodiment, the exposed plant material, CMC, lignin, and kraft lignin are formulated in one PRE without amine chemicals. No extra acidification to corrode the PRE is required. The product in the PRE is a homogeneous mass that is placed in a mold. The mass is then dried to remove excess moisture. The reaction proceeds, and a solid molded article or substance is formed.

[0044] According to one embodiment, the exposed plant material, CMC, and amine (added at 120 - 130 °C) are formulated in one PRE. The product in the PRE is a homogeneous mass that is placed in a mold. The mass is then dried to remove excess moisture. The reaction proceeds, and a solid molded article or substance is formed.

[0045] According to one embodiment, the reactive bio-substance can be formed and dried into several solid bio-products with different structures, such as multi-purpose solids, packaging materials, building materials, and plant pots, which can be used for various purposes. The water resistance of the products can be improved by surface treatments such as wax, paint, or coating with external materials. Most of the methods for extending the usable period of paper cups in a wet environment are applicable.

[0046] The dried bio - composite from straw may have a low product density, which broadens its scope of application to packaging aids.

[0047] When amines and phosphoric acid are used in the production of reactive biomass, the product can function as a soil conditioner and fertilizer. Straw is composed of cellulose, hemicellulose, lignin, a large amount of silicate, and ash containing 2.1 - 6.8 mg / g of potassium. When the pH is high, the solubility of potassium decreases. One possible composition is shown below.

[0048] [Table 1]

[0049] When biomass is recycled in the field, the level of organic matter increases, and the structure, biological activity, and moisture balance of the field are improved. Urea mixed with biomass in PRE can reduce the nitrogen outflow from the field.

[0050] If excess nitrogen, potassium and / or phosphorus is mixed into or with a part of the reactive biomass, the dry mixture can be used as a fertilizer, where nitrogen, potassium and / or phosphorus have their solubilization extended by the cured biomass. However, the said biomass can be decomposed by cellulase enzymes.

[0051] Throughout this specification, reference 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 of the invention. Thus, although the phrases "in one embodiment" or "in an embodiment" are recited throughout the specification, they are not necessarily all referring to the same embodiment. For example, when referring to a numerical value using terms such as "about" or "substantially", the exact numerical value is also disclosed.

[0052] The above embodiments illustrate the principles of the present invention in one or more specific applications. However, it will be apparent to those skilled in the art that numerous changes in the embodiments, usage, and details of implementation can be made without departing from the principles and concepts of the invention, without exercising the capabilities of the invention. Therefore, the present invention is not intended to be limited, except as defined by the claims set forth below.

[0053] In this specification, the verbs "comprise" and "include" are used as open limitations that do not require excluding the presence of features not described. The features described in the dependent claims can be freely combined with each other, unless otherwise explicitly stated. Further, it should be understood that the use of "a" or "an" throughout this document, i.e., the singular form, does not exclude the plural form.

Examples

[0054] Example 1: Production of Reactive Biomass a) Preparation of straw: Straw is cut in the field, collected, and pulverized with an impact mill through a 4 mm sieve (see Figure 1). This is packed into large bags and extruded with a PRE machine. b) Extrusion is carried out at 120 rpm and a temperature of 150 - 220 °C with 25 kg / h of straw, 1.25 - 2.5 kg / h of CMC, and 30 kg / h of water.

[0055] Example 2: Reaction with Kraft Lignin and Urea c) Extrusion is carried out with 59 wt% straw, 23 wt% CMC, 18 wt% kraft lignin, and 78 wt% water based on the total dry weight of the suspension. d) Extrusion is carried out with 56 wt% straw, 22 wt% CMC, 17 wt% kraft lignin, 5 wt% urea, and 70 wt% water based on the dry weight of the suspension.

[0056] Example 3: Raw Materials e) Replace the straw with cellulose, paper, recycled paper, cardboard or sawdust, and perform extrusion under the reaction conditions of Example 1 or Example 2. f) When manufacturing food industry products, replace the kraft lignin with natural lignin, and perform extrusion under the reaction conditions shown in Example 1 or Example 2. g) When manufacturing a more flexible product, replace the lignin with polyvinyl alcohol, and perform extrusion under the reaction conditions shown in Example 1 or Example 2. h) Replace the CMC with starch or alginate, and perform extrusion under the reaction conditions shown in Example 1 or Example 2. i) Supply 79% by weight of straw, 16% by weight of CMC, 5% by weight of sodium alginate, and 70% by weight of water to the extruder based on the dry weight of the suspension. j) Supply 77% by weight of straw, 15% by weight of CMC, 5% by weight of sodium alginate, 3% by weight of urea, and 70% by weight of water to the extruder based on the dry weight of the suspension.

[0057] Example 4: Production of Reactive Biomass under Power Conditions Preparation of straw: The straw is cut in the field, collected, and ground with an impact mill through a 4-mesh sieve (see Figure 1). This is extruded with a PRE machine. k) Perform extrusion at a mixing speed of 120 rpm with 25 kg / h of straw, 1.25 - 2.5 kg / h of CMC, and 30 kg / h of water. l) The first module and the third module have special grinding tools. m) The temperature profile of the said module is shown in Figure 2.

Claims

1. A method for converting plant material into a curable biomass, the method comprising: providing an aqueous suspension comprising the plant material; feeding the suspension to a multi-screw extruder comprising a series of a plurality of extruder modules; optionally adding external carbohydrates to increase the viscosity of the suspension and improve the dough-like state; and in a series of the extruder modules, grinding and / or shearing the suspension at a temperature of at least 150 °C to expose and / or release the carbohydrates and lignin of the plant material, and obtaining a wet and curable reactive biomass comprising the exposed carbohydrates and lignin; A method characterized by comprising at least the above steps.

2. The method according to claim 1, characterized in that the plant material comprises annual and perennial plant materials such as straw, hay, leaves, by-products from grain mills, and recycled materials such as shredded cardboard, paper, wood chips, shredded cotton cloth, shredded straw or oat husks.

3. The method according to claim 1 or 2, characterized in that the multi-screw extruder is a planetary roller extruder (PRE).

4. The method according to any one of claims 1 to 3, characterized in that the external carbohydrates are carboxymethyl cellulose (CMC), starch or alginate.

5. The method according to any one of claims 1 to 4, characterized in that the wet and curable reactive biomass is further mixed with an amine reagent or lignin, formed and dried to form a bio-composite.

6. The method according to any one of claims 1 to 5, characterized in that the wet and curable reactive biomass is further mixed with urea and dried to form a fertilizer or a part of a fertilizer.

7. The method according to any one of claims 1 to 6, characterized by comprising an acidification step after extrusion.

8. The method according to any one of claims 1 to 7, further comprising at least partially filling a mold with the wet and curable reactive biomass obtained from the step of performing the grinding / shearing, and drying the biomass in the mold to produce a solid bio-composite.

9. Use of the method according to any one of claims 1 to 8 in the production of biocomposites, biofertilizers and bioadhesives.

10. Use of the method according to any one of claims 1 to 8 in the production of reactive biomass as a raw material for enzymatic hydrolysis.

11. Use of the wettable and curable reactive biomass produced by the method according to any one of claims 1 to 8 in the production of solid biocomposite objects.

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