Method and system for producing microfibrillated cellulose

Abstract

This document discloses a method and system for manufacturing MFCs. The method according to the present invention includes the following steps: a) A pulp suspension containing cellulose fibers is supplied to a buffer tank (2), where the temperature of the pulp suspension is controlled and adjusted for optimized enzyme function, preferably to ≥20°C; b) Transfer the pulp suspension to the purification unit (3) and purify the pulp to obtain a pre-purified pulp suspension, where the hydrolyzing agent is added to the pulp suspension in the form of an enzyme before and / or after the pre-purification; c) Supply the pre-purified and temperature-controlled pulp suspension to the reactor tank (4,4'); d) Hydrolyzing the purified pulp suspension (4,4') in the reactor tank (4,4') at a temperature between 40 and 70°C under controlled mixing using a stirring member (7); e) Inactivating the enzyme in the reactor tank by heating the hydrolyzed and pre-purified pulp suspension to a temperature of >80°C; f) Cooling the hydrolyzed and pre-purified pulp suspension; g) Discharge the hydrolyzed and pre-purified pulp suspension and subject it to further mechanical treatment to obtain MFC.

Description

Technical Field

[0001] The present invention relates to a method for producing microfibrillated cellulose.

Background Art

[0002] Microfibrillated cellulose ("MFC") is a material composed of cellulose microfibrils that can be separated from the cellulose fiber wall. The liberated fibers have a diameter of less than 1000 nm, while the actual fibril diameter or particle size distribution, and / or aspect ratio (length / width) depend on the source and manufacturing method. The smallest fibrils are called elementary fibrils and can have a diameter of approximately 2 - 4 nm. On the other hand, when making MFC, for example, by using an extended refining process or a high pressure-drop disintegration process (e.g., high-pressure homogenization or fluidization), the main product obtained is generally an aggregated form of elementary fibrils.

[0003] There are various methods for making MFC, which include, for example, single-pass or multi-pass refining, followed by pre-hydrolysis or enzymatic treatment, and then refining or high-shear disintegration, or liberation of fibers. MFC can be produced from wood cellulose fibers, from both hardwood and softwood fibers. It can also be produced from microbial sources, agricultural fibers (e.g., wheat straw pulp, bamboo, bagasse, etc.), or other wood fiber sources. Pulp-based ones are preferred, which include pulp from virgin fibers, such as mechanical, chemical, and / or thermomechanical pulp. MFC can also be made from waste paper or recycled paper. The term MFC also includes parenchymal MFC. MFC can also be obtained from plant fibers, such as sugar beet or potato-based plant fibers.

[0004] Further synonyms for MFC include, for example, cellulose microfibrils, fibrillated cellulose, nanofibrillated cellulose (NFCs), fibril aggregates, nanoscale cellulose fibrils, cellulose nanofibers, cellulose nanofibrils, cellulose microfibers, cellulose fibrils, cellulose nanofilaments, microfibril cellulose, microfibril aggregates, and cellulose microfibril aggregates.

[0005] Current research and development have shown that MFCs, due to their strength and barrier properties, can be suitable materials for packaging and coating packaging substrates. Therefore, MFCs have the potential to replace or complement currently used barrier films (including polymer films and metal films).

[0006] However, current methods for efficiently manufacturing MFCs in terms of energy and materials have proven to have limited capacity and are difficult to upscale and industrially apply. Furthermore, manufacturing MFCs on an industrial scale involves high investment costs, which lead to high manufacturing costs.

[0007] the purpose The object of the present invention is to provide a method and system for manufacturing MFCs in which the drawbacks and problems of the prior art are minimized.

[0008] Another object of the present invention is to provide improved methods and systems that offer novel alternative methods for manufacturing MFCs, particularly in terms of production capacity and efficiency in terms of energy and materials.

[0009] overview The present invention is defined by the attached independent claims, each aspect of which is shown in the dependent claims, the following specification and the attached drawings.

[0010] According to a first aspect of the present invention, a method for producing microfibrillated cellulose (MFC) is provided, the method comprising the following steps: a) A pulp suspension containing cellulose fibers is provided to a buffer tank, where the temperature of the pulp suspension is controlled and adjusted for optimized enzyme function, preferably to ≥20°C; b) Transfer the pulp suspension to a pre-purification unit and purify the pulp to obtain a pre-purified pulp suspension, where the hydrolyzing agent is added to the pulp suspension in the form of an enzyme before and / or after pre-purification; c) Supplying a pre-purified and temperature-controlled pulp suspension to the reactor tank; d) Hydrolyzing the purified pulp suspension in the reactor tank at a temperature between 40 and 75°C under controlled mixing using a stirring device; e) Inactivating the enzyme in the reactor tank by heating the hydrolyzed and pre-purified pulp suspension to a temperature of >85°C; f) Cooling the hydrolyzed and pre-purified pulp suspension; and g) Discharge the hydrolyzed and pre-purified pulp suspension and subject it to further mechanical treatment to obtain MFC. Includes.

[0011] The present invention provides an improved pulp pretreatment method that enables semi-continuous production along with improved temperature control and mixing, and is applicable to medium and / or high concentration pulp or pretreated pulp. Furthermore, the present invention enables an efficient temperature profile in the reaction tank with a rapid temperature rise to promote enzymatic hydrolysis, and enables uniform temperature control in the hydrolyzed pulp for efficient, uniform, and rapid inactivation of the enzyme. This enables predictable, high-quality, and high-yield industrially applicable MFC production while reducing variability in fiber properties (e.g., fiber length) between different batches. It should be noted that the method and system according to the present invention make it possible to eliminate unpredictable variability in fiber length between batches, and the selected fiber length is reproducible. That is, this method leads to predictable fiber quality, which is advantageous.

[0012] Other advantages achieved by the method and system according to the present invention include improved flow behavior of the pulp suspension, efficient mixing, precise control of the temperature gradient during hydrolysis, and enzyme inactivation, while maintaining energy efficiency throughout the process (i.e., no excess energy is consumed). As a result, manufacturing costs are minimized, and the final product can be sold at a competitive market price.

[0013] According to another aspect of the present invention, the pulp suspension is purified in a pre-purification unit to a concentration of 0.5 to 12 wt%, preferably 4 to 7 wt%.

[0014] According to another aspect of the present invention, the pulp suspension is purified in a pre-purification unit to a Schöpper-Leighler (SR) value of 15 to 40, preferably 15 to 35.

[0015] According to yet another aspect of the present invention, the enzyme is a hydrolyzing agent, preferably cellulase, hemicellulase, lignase, swarrenin, or a mixture thereof. The cellulase may be either an exoglucanase or an endoglucanase. The enzyme mixture may also include β-glucosidase. It is understood that “enzyme treatment” may also be called “enzyme treatment” or “enzyme cellulose hydrolysis.”

[0016] According to another aspect of the present invention, the pulp suspension used in step a) may include a mixture of different types of fibers, e.g., kraft fibers, fines, reinforcing fibers, dissolved pulp, TMP, CTMP, or PGW. MFCs can be produced from wood cellulose fibers, either from coniferous or hardwood fibers. They can also be produced from microbial sources, agricultural fibers (e.g., wheat straw pulp, bamboo, bagasse), or other non-wood fiber raw materials. It is preferable that they be produced from pulp (including pulp from virgin fibers), e.g., mechanical, chemical, and / or thermochemical pulp. The pulp can be produced from waste paper or recycled paper. Microfibrilized cellulose may contain some hemicellulose, the amount of which depends on the plant source. Microfibrilized cellulose can also be produced from never-dried pulp. Never-dried MFCs have been found to have much higher enzyme accessibility compared to MFCs produced from dried pulp. It is also preferable that the lignin content of the microfibrillated cellulose is very low, because lignin can negatively affect enzyme activity.

[0017] According to yet another aspect of the present invention, the method is designed to operate as a semi-continuous process. The configuration according to the present invention allows for the use of two or more reactor tanks in parallel, with enzymatic treatment and inactivation taking place in one of them, and the other supplying material for further mechanical treatment to obtain MFCs.

[0018] According to another aspect of the present invention, the stirring member is arranged to generate an axial circulation pattern in which the flow direction in the center of the tank is opposite to the flow direction adjacent to the tank wall. An example of a stirring member suitable for use in the method according to the present invention is a spiral mixer. For example, the flow velocity determined at 1 cm from the reactor tank wall is at least 0.03 m / s, preferably at least 0.04 m / s, most preferably at least 0.05 m / s, for example 0.05 to 0.3 m / s. The flow is preferably determined at least from the center point (height / 2) of the vessel, but it may also be placed at additional positions to determine the stability and variation of the flow rate.

[0019] The present invention also relates to a system for manufacturing MFCs, the system being: A buffer tank configured to receive purified pulp and to control and adjust the pulp temperature (preferably ≥20°C) for optimized enzyme function; • Pre-purification unit combined with a buffer tank; A reactor tank coupled to a pre-purification unit, configured to receive heated pulp along with added enzymes, and to hydrolyze the purified pulp at a temperature between 40 and 75°C using a mixture controlled by a stirring member (i.e., a spiral mixer, etc.), thereby forming a pre-treated pulp suspension; • At least one heat exchanger unit connected in a closed loop to a reactor tank, the heat exchanger unit being configured to control the temperature of the contents of the reactor tank and to inactivate enzymes in the pulp; • Discharge means for obtaining MFC by discharging the inactivated, pre-treated pulp suspension for further purification. It is equipped with these features.

[0020] According to another aspect of the present invention, the system comprises at least one homogenizer configured to be positioned downstream of the reactor tank, wherein the homogenizer is configured to be subjected to mechanical treatment of pulp to obtain MFC.

[0021] According to another aspect of the present invention, the system comprises at least one post-purification unit arranged downstream of the reactor tank and configured upstream of at least one homogenizer.

[0022] According to another aspect of the present invention, the system comprises at least one screening unit arranged downstream of the reactor tank and configured upstream of at least one homogenizer.

[0023] According to another aspect of the present invention, the system comprises more than one reactor tank arranged parallel to each other and configured to alternately discharge the pre-purified and hydrolyzed pulp suspension to the at least one homogenizer.

[0024] According to another aspect of the present invention, the system has a control arrangement which includes a self-learning artificial intelligence unit based on a convolutional neural network arranged to assist in controlling the temperature of the pulp material. Also included within the scope of the present invention are deep learning and / or machine vision, or other applicable systems usable for IR imaging of the reactor, and providing an improved feedback loop for improved temperature regulation, which leads to optimized pulp processing (including hydrolysis).

Brief Description of the Drawings

[0025] [Figure 1] A system according to one example of the present invention is schematically shown. [Figure 2] A preferred circulation pattern inside the reactor tank is schematically shown.

Modes for Carrying Out the Invention

[0026] The drawings schematically illustrate a system on which the present invention can be implemented.

[0027] Figure 1 schematically shows System 1 according to the present invention for pre-treating cellulose pulp before MFC production. As shown herein, System 1 comprises a buffer tank 2 configured to receive the pulp and control / adjust the temperature of the pulp for optimized enzyme function, preferably ≥20°C depending on the enzyme. For example, the temperature of the pulp in the buffer tank may be adjusted to between 20 and 85°C. Sometimes, the pulp in the buffer tank 2 can be heated to ≥50°C, preferably between 50 and 85°C, or between 50 and 75°C. A pre-purification unit 3 is coupled to the buffer tank 2, and the pulp is supplied to the unit 3 at a controlled flow rate. The pulp suspension is purified in the pre-purification unit 3 to a concentration between 0.5 and 12 wt%. A hydrolyzing agent is added to the pulp suspension in the form of an enzyme before and / or after the pre-purification step. It is preferable that the enzyme be added with high shear mixing so that it is uniformly mixed with the pulp. At least one reactor tank 4 is coupled to a pre-purification unit 3, which is configured to receive purified and heated pulp along with added enzymes. The pulp is hydrolyzed in the reactor tank 4 at a temperature between 40 and 75°C under controlled mixing using a stirring member 7 (i.e., a spiral mixer, etc.), thereby forming a pre-treated pulp suspension. To improve mixing efficiency, enzymes may be added at one or more dosing points. The enzyme dosage may also be controlled based on the desired MFC quality and characteristics measured for the pulp received in the buffer tank 2 (pulp viscosity, pH, temperature), or characteristics measured for the pulp after pre-purification in the pre-purification unit 3 (fiber length, Schöpper-Leighler number). A temperature control unit (e.g., at least one heat exchanger 50, 51) is coupled to the reactor tank 4 in a closed loop and is configured to control and regulate the temperature of the reactor tank contents. The temperature and mixing within the reactor tank are optimized to achieve efficient and uniform enzymatic hydrolysis of the pulp.

[0028] After the desired processing time, i.e., after the desired fiber length and fine particle content are achieved in the slurry, the enzymes present in the reactor tank 4 are inactivated to stop hydrolysis. The fiber length can be measured, for example, by an FS5 fiber analyzer. Enzyme inactivation is achieved by raising the pulp temperature to at least >85°C, during which time uniform mixing of the pulp is ensured to guarantee enzyme inactivation throughout the entire pulp volume. The inactivation temperature can be further >90°C, for example, between 90 and 99°C. According to the present invention, the spatial temperature control of the reactor tank 4 is optimized so that, after the heating or cooling operation, the temperature variation of the contents of the reactor tank is measured to be less than 25°C, preferably less than 15°C, for example between 0.5 and 15°C, in different parts of the reactor or over time for at least 30 minutes, preferably at least 60 minutes. In other words, the temperature profile in the reactor tank is kept uniform, and complete enzyme inactivation is achieved in a short time. Enzyme inactivation in pulp slurry can be measured by conventional methods known to those skilled in the art, such as using the Megazyme Cellulase Assay Kit (product code: "K-CellG5-4V").

[0029] The system also includes a discharge means for discharging an inactivated and pre-treated pulp suspension, and a discharge means for further purification to obtain an MFC.

[0030] In one embodiment, the system 10 includes at least two reactor tanks (4,4') arranged in parallel, each of which is coupled to both an upstream pre-purification unit 3 and a downstream continuous process. In Figure 2, the second reactor tank 4' is shown by a dotted line and is arranged in parallel with the first tank 4. According to the present invention, the multiple reactor tanks 4,4' are arranged and configured to process pulp alternately, thereby enabling semi-continuous MFC production. This means that when the first reactor tank 4 is filled with pulp, enzymes have been added and hydrolysis has been completed under controlled mixing and temperature control, and the second reactor tank 4' is ready to discharge the pre-treated and hydrolyzed pulp. Once the discharge from the second tank 4' is complete, new pulp is supplied, enzyme administration is complete, and the first tank 4 is ready to discharge the batch, etc. Clearly, it is also possible to place two or more reactor tanks in parallel to increase the system's capacity.

[0031] At least one homogenizer 6 is coupled to the reactor tanks 4,4' and is arranged to mechanically process the pulp to obtain an MFC by circulating the material for the required time at the target fibrillation gap, pressure, and flow rate. Multiple homogenizers (e.g., 2 to 5) in series with an intermediate heat exchanger may also be installed to cool the material. The number of homogenizers in series depends on the average size and distribution (i.e., degree of fibrillation) required for the MFC in the intended application.

[0032] In one embodiment, the system 10 according to the present invention comprises at least one post-purification unit (not shown) positioned between the reactor tanks 4, 4' and the at least one homogenizer 6.

[0033] The pre-treated and hydrolyzed pulp discharged from reactor tanks 4,4' is subjected to mechanical treatment to obtain MFCs. Further mechanical treatment may include apparatus suitable for pulp processing into an MFC suspension. For example, a further mechanical treatment arrangement may include at least one mechanical fiber processing apparatus. Each mechanical fiber processing apparatus may be selected from the group consisting of refiners, homogenizers / fluidizers, defibrators, deflakers, beaters, friction grinders, high-shear fibrillators (e.g., cavitron rotor / stator systems, steam explosion systems, or high-viscosity refining or milling systems), dispersers, ball mills, and other known and suitable mechanical fiber processing apparatuses that can be used to process pulp into MFCs, or combinations thereof. The pulp may pass through each of the mechanical fiber processing apparatuses used one or more times. Optionally, the fibrillation configuration may further comprise one or more pretreatment devices, each configured to pretreatment the pulp by mechanical, enzymatic, or chemical modification. For example, the fibrillation configuration may include at least one mechanical fiber pretreatment device. Each mechanical fiber pretreatment device may be selected from the group consisting of refiners, defiberators, deflakers, beaters, shredders, ball mills, rotor-stator mixers, ultrasonic devices, steam explosion devices, and known mechanical fiber pretreatment devices suitable for mechanically pretreatment of cellulose fibers.

[0034] The present invention also relates to a method for pre-treating pulp in MFC manufacturing. The method includes the following steps: a) A pulp suspension containing cellulose fibers is supplied to a buffer tank 2, where the pulp suspension is heated and maintained at a temperature of ≥20°C; b) Transfer the pulp suspension to the pre-purification unit 3, purify the pulp to obtain a pre-purified pulp suspension, where the hydrolyzing agent is added to the pulp suspension in the form of an enzyme before and / or after pre-purification; c) Supply the pre-purified and temperature-controlled pulp suspension to either reactor tank 4, 4'; d) Hydrolyze the purified pulp suspension by enzymatic treatment in the reactor tanks 4,4' at a temperature between 40 and 75°C under controlled mixing using the stirring member 7; e) Inactivating the enzymes in the reactor tank by heating the hydrolyzed and pre-purified pulp suspension to a temperature of >85°C; f) Cooling the hydrolyzed and pre-purified pulp suspension; g) Discharge the hydrolyzed and pre-purified pulp suspension and subject it to further processing to obtain MFC. The target fiber length of the hydrolyzed pulp is 15% to 90% of the original fiber length of the raw material.

[0035] Enzymatic hydrolysis is carried out in reactor tank 4,4'. The enzyme is a wood-degrading enzyme, preferably a cellulase enzyme. Enzymatic hydrolysis of cellulose is preferably carried out by cellulase, but is not limited to cellulase. These typically catalyze the hydrolysis of β-1,4-glucosidic bonds in the cellulose chains of pulp fibers. The cellulase may be an exoglucanase or an endoglucanase, or a mixture thereof. The enzyme or enzyme mixture, or enzyme "cocktail," may preferably contain other wood-degrading or hydrolyzable chemicals, such as hemicellulases (e.g., xylanase and / or manase). The amount of enzyme may be 20 to 500 ECU per gram of dry pulp, but is not limited to this amount.

[0036] The pulp is preferably made from hardwood or softwood. The pulp is preferably bleached kraft pulp with a kappa content of <25 and a hemicellulose content of >5%.

[0037] The tanks 4,4' are provided with stirring members, such as mixers 7,7', to ensure uniform mixing of the tank contents and uniform temperature control of the suspension. A suitable example of a stirring member is a spiral mixer that reaches the bottom and inner walls of the tanks 4,4'. The stirring members 7,7' are preferably arranged and configured to generate an axial flow circulation pattern F within the reactor tank 4, where the flow direction in the center of the tank is opposite to the flow direction adjacent to the tank walls. An example of a preferred flow pattern is schematically shown in Figure 2 (where the mixer is not shown). For example, the flow velocity determined at 1 cm from the reactor tank wall 40 (see Figure 2) is at least 0.03 m / s, preferably at least 0.04 m / s, most preferably 0.05 m / s, for example, 0.05 to 0.3 m / s. The flow rate is preferably determined from at least the midpoint (height / 2) of the container 4, but it may also be placed at additional locations to determine flow stability and flow rate changes.

[0038] By uniformly mixing the pulp suspension in reactor tanks 4,4', the enzyme distribution is kept uniform throughout the material, and the pulp is uniformly processed / hydrolyzed throughout its entire volume. Furthermore, the pulp temperature, enzyme concentration, and pH can be controlled and adjusted as needed, ensuring consistent properties of the pulp discharged from the tank. Additionally, enzyme inactivation is more efficient if the temperature can be rapidly and uniformly raised throughout the entire volume of tanks 4,4'. There is a risk that some enzymes may remain active in the relatively cooler regions of tanks 4,4', which can lead to further hydrolysis of the fibers / fibrils and degrade the quality of the MFC. The level of enzyme inactivation is achieved when no detectable residual enzymes remain in the pulp. The minimum processing capacity of the MFC plant can start with 1 ton of dry MFC per day. [Examples]

[0039] Example 1 Pre-purified pulp with an SR value of 32 and enzymes, 28m 3The mixture was prepared in a tank (equipped with a propeller mixer at the bottom and two material circulation loops from the bottom to the top of the tank). The dry content of the material was 5.3 wt%.

[0040] After enzymatic treatment, the material temperature was raised to over 90°C by a heat exchanger in one of the circulating flow channels. After the material reached this temperature, temperature sensors installed in the heat exchanger loop were used to observe the temperature in different areas of the tank using an infrared camera on the tank surface. There were large, relatively cold areas at the bottom of the tank and near the walls further away from the circulating loop. Some of the material had zero flow velocity (i.e., was not moving).

[0041] This non-uniform temperature profile leads to non-uniform enzyme inactivation, which means that the kinetics of cellulose hydrolysis also fluctuate. Non-uniform hydrolysis increases the amount of rejected and intact fibers, and risks increasing the content of low molecular weight material that dissolves in the aqueous phase.

[0042] Example 2 The pre-purified pulp and enzyme were mixed in the same tank as in Example 1, but the dry content of the pre-purified pulp was reduced to 4.3 wt%. At this concentration, the viscosity of the pulp was low enough that the propeller mixer moved the pre-purified pulp throughout the entire tank volume. After enzymatic treatment, the temperature rose to over 90°C. A temperature sensor in the heat exchanger loop confirmed that the temperature had reached 90°C (the temperature was observed from outside the tank with an infrared camera). Compared to Example 1, the temperature was more uniform throughout the entire test area.

[0043] Example 3 The hydrolyzed and purified pulp suspension is prepared in 25 ml. 3The mixture was prepared in a tank (equipped with a spiral mixer at the bottom and a single material circulation loop from the bottom to the top of the tank). The dry content of the material was 4.2 wt%. The vertical flow velocity at 1 cm from the tank wall was 0.28 m / s. The material was heated to 37.2°C. When a temperature sensor in the heat exchange loop indicated that the temperature had reached 37.2°C, the temperature was observed from outside the tank with an infrared camera. Compared to Example 1, the temperature was uniform throughout the inspection area. The maximum temperature difference measured was 7°C. However, the measurement was made due to the mirroring effect of the tank steel surface caused by changes in emissivity. Emissivity changes with the distance and angle between the measurement point and the FLIR camera. The actual temperature difference is less than 7°C.

[0044] A preferred configuration according to the present invention includes a reactor and a temperature sensor inside the reactor (i), and temperature sensors before the heat exchanger (ii), after the heat exchanger (iii), and optionally inside the heat exchanger (iv). Temperature stability and uniformity can be tracked by monitoring the temperatures at various locations (i-iv) with one or more temperature sensors. The examples shown in Table 1 below particularly illustrate the role that mixing plays in temperature uniformity within the reactor. TIFF2026518389000002.tif47170Table 1

[0045] In summary, a simplified process for producing MFCs is proposed, which can be implemented on an industrial scale due to its semi-continuous operation. The resulting pre-treated pulp will have uniform quality due to efficient hydrolysis in the tank and careful control of process parameters (e.g., temperature changes, mixing operations, and uniform distribution within one or more reaction tanks). Scalability is considered improved compared to current process solutions due to the simplification, as is the ability to maintain the process at high hygienic standards.

[0046] In view of the above detailed description of the present invention, other modifications and variations will also become apparent to those skilled in the art. However, it should be clear that such other modifications and variations can be made without departing from the spirit and scope of the present invention.

Claims

1. A method for producing microfibrillated cellulose (MFC), comprising the following steps: a) A pulp suspension containing cellulose fibers is supplied to a buffer tank (2), where the temperature of the pulp suspension is controlled and adjusted for optimized enzyme function, preferably to ≥20°C; b) Transfer the pulp suspension to the purification unit (3) and purify the pulp to obtain a pre-purified pulp suspension, where the hydrolyzing agent is added to the pulp suspension in the form of an enzyme before and / or after pre-purification; c) Supply the pre-purified and temperature-controlled pulp suspension to the reactor tank (4, 4'); d) Hydrolyzing the purified pulp suspension (4,4') in the reactor tank (4,4') at a temperature between 40 and 70°C under controlled mixing using a stirring member (7); e) Inactivating the enzyme in the reactor tank by heating the hydrolyzed and pre-purified pulp suspension to a temperature of >80°C; f) Cooling the hydrolyzed and pre-purified pulp suspension; g) Discharge the hydrolyzed and pre-purified pulp suspension and subject it to further mechanical treatment to obtain MFC. Methods that include...

2. The method according to claim 1, wherein the pulp suspension is purified in the purification unit to a viscosity between 0.5 and 12 wt%, preferably between 4 and 7 wt%.

3. The method according to claim 1 or 2, wherein the pulp suspension liquid is purified in the purification unit to a Schöpper-Leighler (SR) value between 15 and 40, preferably between 15 and 35.

4. The method according to any one of claims 1 to 3, wherein the hydrolysis is obtained by enzymatic treatment, and preferably the enzyme is a wood-degrading enzyme, and preferably a cellulase enzyme.

5. The method according to any one of claims 1 to 4, configured to operate as a semi-continuous process.

6. The method according to any one of claims 1 to 5, wherein the stirring member (7) is arranged to generate an axial flow circulation pattern (F) within the reactor tank (4), and the flow direction in the center of the tank is opposite to the flow direction adjacent to the tank wall.

7. The method according to any one of claims 1 to 6, wherein heating and cooling of the contents of the reactor tank are achieved by at least one closed-loop heat exchange system (50, 51).

8. A system for manufacturing MFCs, - A buffer tank (2) configured to receive the purified pulp and adjust the temperature of the pulp to a temperature of ≥20°C; - Pre-purification unit (3) coupled with buffer tank (2); - A reactor tank (4) coupled to the pre-purification unit (3), configured to receive heated pulp together with added enzymes and to support the hydrolysis of the purified pulp at a temperature between 40 and 75°C under controlled mixing using a stirring member (7), thereby forming a pre-treated pulp suspension; - A heat exchanger unit (5) connected in a closed loop to a reactor tank (4), wherein the heat exchanger unit is configured to control the temperature of the contents of the reactor tank; - Discharge means for obtaining MFC by discharging the inactivated, pre-treated pulp suspension for further purification. A system that includes these features.

9. The system according to claim 8, further comprising at least one fluidizer, a high-speed mixer, an extruder, a grinder, a refiner, or preferably one homogenizer (6), which is coupled to the reactor tank (4) and configured to be used for mechanical processing of pulp to obtain MFC.

10. The system according to claim 9, further comprising at least one post-purification unit configured to be positioned between the reactor tank (4) and at least one homogenizer (6).

11. The system according to claim 8, comprising one or more reactor tanks (4, 4') arranged in parallel with each other, and configured to alternately discharge pre-purified and hydrolyzed pulp suspensions to at least one homogenizer.

12. The system according to claim 8, wherein the system (1) includes a control arrangement configuration, the control arrangement configuration being arranged to assist in temperature control of pulp material, and the system includes a self-learning artificial intelligence unit based on a convolutional neural network.

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