Composite bio-enzyme assisted low-energy-consumption pulping method

Abstract

The invention relates to the technical field of pulping and papermaking, and provides a composite biological enzyme assisted low-energy-consumption pulping method. The method comprises the following steps: S100, pretreating raw materials, adding a compound bio-enzyme preparation and a softening agent, and carrying out softening treatment to obtain a mixture; s200, performing mechanical pulping on the mixture, and performing filament separation treatment through twisting and grinding equipment to form pulp; s300, bleaching treatment and cleaning treatment are conducted on the pulp, and the pulping process is completed; wherein the composite biological enzyme preparation comprises laccase, cellulase, xylanase, pectinase and magnetic particles. The composite bio-enzyme preparation can reduce energy consumption in the pulping process, is beneficial to reduction of production cost and improvement of production efficiency, replaces traditional chemical agents with the composite bio-enzyme preparation, reduces environmental pollution, effectively improves the decomposition rate of plant fibers, enables pulp to be easier to obtain, and improves the utilization rate of raw materials.

Description

Technical Field

[0001] The invention relates to the technical field of pulping and papermaking, and in particular to a composite bio-enzyme-assisted low-energy pulping method. Background Art

[0002] Papermaking production is divided into two basic processes: pulping and papermaking. Papermaking is to combine pulp fibers suspended in water into paper sheets that meet various requirements through various processes. Biopulping is one of the process directions of detergent pulping. The pulp prepared by biopulping has long fibers, high pulp yield, strong resistance to demolition, and the cost per ton of pulp is much lower than that of chemical pulp and mechanical pulp. However, due to the high requirements for the cultivation, selection and pulping conditions of biological strains, there are many problems such as large production fluctuations, uneven material handling, long processing time, and low production efficiency. Biopulping is currently difficult to industrialize.

[0003] Traditional mechanical pulping methods usually require a lot of energy, resulting in high production costs. Energy consumption not only affects economic benefits, but also increases the burden on the environment. At the same time, the pulp processing speed is slow, and the efficiency of enzymatic hydrolysis and mechanical treatment is not high, affecting the overall production efficiency. Summary of the invention

[0004] Therefore, the present invention provides a composite bio-enzyme-assisted low-energy pulping method, which aims to solve the problems of high energy consumption and low efficiency in the traditional pulping process. By using composite bio-enzymes such as laccase, cellulase and pectinase, and using ultrasound during the enzymatic hydrolysis process, the activity and enzymatic hydrolysis efficiency of the enzyme can be improved, and the enzymatic hydrolysis efficiency of the raw materials can be enhanced, thereby reducing energy consumption; at the same time, different enzymes are processed and cross-linked in steps to ensure that each enzyme reacts under optimal conditions to increase the reaction efficiency.

[0005] The present invention provides a composite bio-enzyme-assisted low-energy pulping method, the method comprising:

[0006] S100: pretreating the raw materials, adding composite bio-enzyme preparations and softeners, performing enzymolysis treatment under ultrasound to obtain a mixture; S200: mechanically pulping the mixture, performing fiber separation treatment through rubbing and grinding equipment to form a slurry; S300: bleaching and cleaning the slurry to complete the pulping process; wherein the composite bio-enzyme preparations include laccase, cellulase, pectinase, and magnetic particles.

[0007] Compared with the prior art, the technical effects achieved by adopting this technical solution are as follows: the composite bio-enzyme-assisted low-energy pulping method of the present invention utilizes bio-enzymes to partially degrade plant cellulose and hemicellulose, which can reduce the energy consumption in the subsequent mechanical pulping process, making the raw materials softer and reducing the power and energy consumption required for grinding; at the same time, the use of composite bio-enzymes helps to retain the fiber structure, reduce fiber damage, and maintain fiber strength. The fibers treated with enzymatic hydrolysis can be separated more evenly during the silk separation process, thereby improving the quality of the final pulp; in the bleaching step S300, due to the change in the raw material structure after enzymatic hydrolysis, the bleaching treatment is more The method is more efficient, the amount of bleaching chemicals required is reduced, and the bleaching effect is improved. The final pulp color is whiter and brighter. In addition, the method reduces the dependence on energy-consuming equipment such as high temperature and high pressure through the application of biological enzymes, reduces the use of chemical bleaching agents, thereby reducing harmful chemicals in wastewater, and has a good environmental protection effect. In general, through auxiliary technologies such as ultrasonic enzymatic hydrolysis and magnetic particles, the action of enzymes is accelerated, the processing time is shortened, and the overall pulping efficiency is improved, which helps to reduce production costs, achieve low-energy production while ensuring the quality of pulp fibers, and has high environmental protection, which meets the needs of modern green production.

[0008] In a technical scheme of the present invention, in step S100, the preparation method of the composite biological enzyme preparation includes: S110: dispersing laccase in a phosphate buffer solution, then adding magnetic particles, performing a first stirring treatment, adding a cross-linking agent, and washing with a phosphate buffer after the reaction is completed to obtain a first solvent; S120: dispersing cellulase in a phosphate buffer, adding a first solvent, performing a second stirring treatment, adding a cross-linking agent, and washing with a phosphate buffer after the reaction is completed to obtain a second solvent; S130: dispersing pectinase in a phosphate buffer, adding a second solvent, performing a third stirring treatment, adding a cross-linking agent, and washing with a phosphate buffer after the reaction is completed to obtain a third solvent; S140: washing the third solvent with a phosphate buffer to obtain a composite biological enzyme preparation.

[0009] Compared with the prior art, the technical effects achieved by adopting this technical solution are as follows: the preparation method of the composite bio-enzyme preparation adopts the layered fixation technology to gradually disperse and fix different types of enzymes on magnetic particles to form a composite bio-enzyme preparation with a layered structure, which can separate different enzymes, reduce direct contact between enzymes, avoid possible mutual inhibition or incompatibility, and ensure the activity stability of each enzyme, especially between laccase, cellulase and pectinase, effectively reducing the enzyme activity loss caused by the interaction; the layered fixation can decompose different raw material components in the required order, laccase decomposes lignin to expose cellulose, and then cellulase further The enzyme acts on cellulose, and pectinase processes the pectin component. The synergistic effect of the three effectively improves the efficiency of raw material decomposition, ensuring that each enzyme plays the maximum role in its specific decomposition task, and improving the overall enzymatic efficiency; the enzymes in each layer are fixed by magnetic particles to reduce the loss of enzymes, and can provide certain physical support for each layer of enzymes, so that the enzymes are not easy to separate from the composite system during the treatment process, thereby improving their stability and durability; in addition, the composite biological enzymes after layering and fixing are magnetic, and the enzyme preparations can be quickly recovered from the pulp through an external magnetic field after pulping is completed, thereby reducing the enzyme consumption in the pulping process, allowing the enzyme preparations to be recycled for multiple times, thereby reducing costs;

[0010] On the other hand, the cross-linking agent forms a certain cross-linking structure between laccase, cellulase and pectinase molecules, which helps to improve the stability of the enzyme and avoid the reduction of activity caused by high temperature, pH change and other factors. This treatment prolongs the action time of the enzyme and improves the activity and efficiency of the enzyme in the low-energy pulping process; in each step, the pH is controlled by phosphate buffer, and multiple washing and stirring treatments are performed to ensure the uniform distribution of each enzyme and the purity of the preparation, so that the enzyme is more uniform when contacting the raw materials, effectively improving the enzymatic efficiency, thereby completing the fiber processing in a shorter time, ensuring that the activity of the prepared composite enzyme preparation in the low-energy pulping process is optimized.

[0011] In one technical solution of the present invention, in step S110, the concentration range of laccase is between 6.0g / L-7.0g / L; and / or in step S110, the first stirring treatment temperature is 3°C-6°C; and / or in step S120, the concentration range of cellulose is between 1.0g / L-5.0g / L; and / or in step S120, the second stirring treatment temperature is 20°C-25°C; and / or in step S130, the concentration range of pectin is between 0.5g / L-2g / L; and / or in step S130, the third stirring treatment temperature is 20°C-25°C; and / or the time of the first stirring treatment, the second stirring treatment and the third stirring treatment is 0.5h-1h; and / or the rotation speed of the first stirring treatment, the second stirring treatment and the third stirring treatment is between 70rpm-120rpm; and / or the cross-linking agent includes at least one of glutaraldehyde, EDC, and NHS.

[0012] Compared with the prior art, the technical effects achieved by the technical scheme are as follows: by controlling the concentration range of laccase, cellulase and pectinase, it can effectively ensure that each enzyme reaches an appropriate amount of catalytic effect. The concentration within this range can not only provide sufficient enzyme activity, but also avoid the waste of enzyme resources caused by excessively high concentrations. The control balances the amount of enzyme used and its activity effect, and can reduce costs while ensuring efficiency; in step S110, low-temperature stirring treatment can effectively prevent thermal inactivation of laccase and ensure its activity stability during the preparation process. Low-temperature treatment reduces the degradation rate of protein and prolongs the effective activity time of the enzyme, which is beneficial to thermosensitive enzymes and helps to ultimately improve the long-lasting activity of the composite enzyme preparation; in steps S120 and S130, cellulase and pectinase are stirred at room temperature. At this temperature, the molecular activities of cellulase and pectinase are enhanced. It can be more fully combined with the substrate, optimize the enzymatic hydrolysis effect of the composite preparation, and enhance the synergistic effect among the enzyme levels; selecting a stirring time of 0.5h-1h and a rotation speed of 70rpm-120rpm can avoid damage to the enzyme structure caused by excessive stirring while ensuring uniform dispersion of each enzyme, and can avoid excessive mechanical shear force from damaging the active center of the enzyme, while ensuring that the enzyme is fully combined with the magnetic particles and the cross-linking agent to form a stable composite structure; the cross-linking agent is used to connect different enzymes with the magnetic particles, which can effectively fix the position of the enzyme and prevent its loss during use, and glutaraldehyde provides a bifunctional group, which helps to achieve a stronger cross-linking effect; EDC and NHS react under specific conditions to generate stable ester bonds or amide bonds, so that the enzyme is fixed on the surface of the magnetic particles, which not only maintains the enzyme activity, but also enhances the recycling capacity of the composite enzyme preparation.

[0013] In a technical solution of the present invention, in step S100, the pretreatment includes: water washing treatment and oxidation treatment; and / or the temperature of the enzymatic treatment is between 45°C and 55°C; and / or the time of the enzymatic treatment is 2h-3h.

[0014] Compared with the existing technology, the technical effects achieved by adopting this technical solution are as follows: water washing treatment can remove dust, mud and other impurities on the surface of the raw materials, reduce unnecessary pollution in subsequent processes, improve the purity of the slurry, and reduce the soluble substances in the raw materials, such as some soluble sugars or inorganic salts, to avoid affecting the activity of the enzyme in the subsequent steps or causing the quality of the slurry to deteriorate; oxidation treatment can remove part of the lignin and enhance the exposure of cellulose, thereby improving the enzymatic hydrolysis effect under the condition of low chemical addition, and has environmental advantages; within the temperature range of 45℃-55℃, the composite production The enzymatic activity of the bio-enzyme preparation can reach a high level. This temperature can not only ensure the activity of the enzyme, but also avoid high energy consumption or enzyme inactivation caused by excessively high temperature, thereby ensuring the efficiency of the enzymatic process and accelerating the decomposition process of the enzyme on the raw materials; the enzymatic time is controlled at 2h-3h, which can not only ensure the full decomposition of the raw material cellulose, hemicellulose and pectin by the composite biological enzyme, but also avoid the waste of enzyme resources or possible fiber degradation caused by long-term enzymatic hydrolysis, so that the fiber structure is partially softened and loosened, which can make the subsequent mechanical pulping step easier, further reduce energy consumption and improve pulping quality.

[0015] In a technical solution of the present invention, in step S200, the mass concentration of the slurry is adjusted to 12%-16%; and / or the pH value of the slurry is adjusted to 5.5-6.5.

[0016] Compared with the prior art, the technical effects achieved by adopting the technical scheme are as follows: at a mass concentration of 12%-16%, the slurry has an appropriate fiber distribution density, which can effectively separate fiber bundles during mechanical pulping, help to obtain uniform slurry, and improve the uniformity and quality of the final pulp. The moderate concentration makes the friction and collision between fibers moderate, which can be quickly separated in the mechanical pulping equipment, reducing the time and energy consumption of mechanical pulping. Too high a concentration will increase the equipment load and wear, while too low a concentration will lead to low pulping efficiency. Therefore, this concentration balances the equipment load and pulping efficiency and extends the service life of the equipment. The pH value between 5.5 and 6.5 is the optimal activity range of the composite bio-enzyme preparation. This pH condition ensures the stability and high activity of the enzyme when decomposing cellulose and hemicellulose, further improving the pulping efficiency. At the same time, the fiber structure is more stable and will not be damaged due to too low or too high a pH value, which is conducive to maintaining the strength and fiber length of the pulp and improving the physical properties of the final pulp product.

[0017] In one technical solution of the present invention, in step S300, the bleaching treatment includes adding hydrogen peroxide to the slurry at a temperature range of 45°C-55°C to react for 3h-5h.

[0018] Compared with the existing technology, the technical effect achieved by adopting this technical solution is: when the temperature range is 45℃-55℃, the oxidation ability of hydrogen peroxide is stronger, which can more effectively decompose impurities and pigment molecules in cellulose, thereby improving the bleaching effect and making the pulp whiter. The bleaching treatment at this temperature avoids fiber degradation or strength loss that may be caused by high temperature, ensures the physical properties of the slurry, and thus ensures the toughness and strength of the finished pulp. Compared with the bleaching process at a higher temperature, this temperature range is more economical in terms of energy consumption, meets the goal of low energy consumption, and contributes to overall energy saving; reaction time In 3h-5h, hydrogen peroxide can fully oxidize and decompose impurities and pigment molecules in the pulp under mild conditions, achieving higher bleaching uniformity and stability, avoiding excessive oxidation of fibers by hydrogen peroxide, protecting the fiber structure, maintaining the strength and quality of the pulp, and reducing the consumption of hydrogen peroxide. At the same time, it can effectively oxidize the lignin and pigment molecules remaining in the pulp, thereby improving the whiteness of the pulp and reducing the subsequent need to adjust the bleaching degree. In addition, hydrogen peroxide is an environmentally friendly bleaching agent, which eventually decomposes into water and oxygen during the bleaching process, does not produce harmful by-products, and is environmentally friendly.

[0019] In a technical solution of the present invention, in step S100, the softener includes at least one of polyvinyl alcohol, CTAC, and starch.

[0020] Compared with the prior art, the technical effects achieved by adopting this technical solution are as follows: polyvinyl alcohol can form a soft protective film on the fiber surface, reduce the friction between fibers, make the fibers softer, and facilitate subsequent mechanical separation and beating, and it has good film-forming and adhesion properties, which can improve the bonding strength between fibers, maintain the strength and toughness of pulp, thereby improving the physical properties of finished paper. At the same time, polyvinyl alcohol can effectively disperse the composite biological enzyme, promote its uniform distribution on the fiber surface, and improve the uniformity and efficiency of enzymatic hydrolysis; CTAC is a cationic surfactant that can neutralize the negative charge on the fiber surface, reduce the electrostatic repulsion between fibers, enhance the flexibility of fibers, and facilitate the enzyme to better contact and act on the fibers. In addition, CTAC It has a certain antibacterial effect, can reduce the growth of microorganisms in the pulping process, prevent pulp contamination, ensure the purity and quality of pulp, improve the stability of the slurry, prevent fiber agglomeration during enzymatic hydrolysis, promote the uniform dispersion of fibers, and enhance the enzymatic hydrolysis effect; starch forms a hydrated film in the slurry, which helps to reduce the friction between fibers, improve the lubricity of fibers, make the fibers easier to disperse, and facilitate the subsequent mechanical pulping process. At the same time, the addition of starch can appropriately increase the viscosity of the slurry, thereby enhancing the stability of the slurry, avoiding fiber precipitation or agglomeration, and ensuring the uniformity of pulping. In addition, because starch has a certain adhesiveness, it can improve the mutual bonding force between fibers, improve the strength and toughness of the final pulp, and help to obtain high-quality finished pulp.

[0021] In a technical solution of the present invention, in the composite bio-enzyme preparation, the mass percentages of the components are: laccase: 0.5%-5%, cellulase: 1%-5%, pectinase: 0.5%-2%.

[0022] Compared with the prior art, the technical effects achieved by adopting this technical solution are as follows: laccase can oxidize and decompose lignin in the fiber, reduce the residual lignin in the fiber, improve the whiteness and purity of the pulp, make the residual lignin in the fiber easier for subsequent bleaching, effectively reduce the amount of bleaching agent, improve the bleaching efficiency and reduce chemical residues. In addition, under this ratio, laccase can gently decompose lignin, reduce the damage to the fiber strength, thereby maintaining the physical properties of the pulp; cellulase can decompose the microfibrils in the cellulose structure, reduce the compactness of the molecular structure inside the fiber, make the fiber easier to separate during the pulping process, facilitate the homogenization of the pulp, make the fiber softer, and help the subsequent Mechanical silk separation and rubbing treatment can reduce energy consumption and improve the uniformity of pulp. In addition, cellulase at this ratio can increase the porosity and water absorption of fibers, which is helpful for the water absorption and flexibility of finished pulp, meeting the demand for high-quality paper. Pectinase can decompose pectin substances in plant cell walls, effectively remove pectin impurities in pulp, improve the purity and whiteness of pulp, decompose pectin substances, reduce the adhesion between fibers, and is beneficial to the dispersion and uniform distribution of fibers in the pulping process, preventing fiber agglomeration by decomposing pectin. In addition, pectinase at this ratio improves the fluidity and stability of pulp, making the pulp more uniform and stable during the entire pulping and bleaching process.

[0023] In one technical solution of the present invention, in the composite bio-enzyme preparation, the mass percentages of the components are: laccase: 1%, cellulase: 2%, pectinase: 0.5%.

[0024] Compared with the existing technology, the technical effect achieved by adopting this technical scheme is as follows: through the ratio design of the composite biological enzyme preparation, the efficient decomposition of lignin, cellulose, hemicellulose and pectin can be achieved in the pulping process, the enzymatic hydrolysis effect is optimized, and the composite biological enzyme preparation under this component ratio can maximize the whiteness, purity and uniformity of the pulp, while reducing energy consumption and the use of chemical reagents, realizing an environmentally friendly and efficient pulping process, and ultimately obtaining high-quality pulp.

[0025] After adopting the technical solution of the present invention, the following technical effects can be achieved:

[0026] (1) The preparation method of the present application optimizes the traditional pulping process through the application of biological enzymes, improves production efficiency, shortens the production cycle, and reduces the operating costs of labor and equipment. The use of biological enzymes instead of traditional chemical treatments not only reduces the use of chemical substances, but also reduces the emission of wastewater and waste gas, which is in line with the concept of green production;

[0027] (2) Through the layered fixation of composite biological enzymes, different raw material components can be decomposed in the required order. Laccase decomposes lignin to expose cellulose, followed by cellulase further acting on cellulose, and pectinase treating pectin components. The synergistic effect of the three effectively improves the efficiency of raw material decomposition, ensuring that each enzyme plays the maximum role in its specific decomposition task, thereby improving the overall enzymatic efficiency. At the same time, it reduces direct contact between enzymes, avoids possible mutual inhibition or incompatibility, ensures the activity stability of each enzyme, and effectively reduces the enzyme activity loss that may be caused by interaction.

[0028] (3) Each layer of enzyme is fixed by magnetic particles to reduce the loss of enzymes and provide a certain physical support for each layer of enzymes, so that the enzymes are not easily separated from the composite system during the treatment process, thereby improving their stability and durability; in addition, the composite biological enzymes after layered fixation are magnetic. After pulping is completed, the enzyme preparation can be quickly recovered from the pulp by an external magnetic field, thereby reducing the enzyme consumption during the pulping process and enabling the enzyme preparation to be recycled multiple times, thereby reducing the cost of using layered fixation technology. DETAILED DESCRIPTION

[0029] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and understandable, the technical solutions in the embodiments of the present invention are described clearly and completely. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] Papermaking production is divided into two basic processes: pulping and papermaking. Papermaking is to combine pulp fibers suspended in water into paper sheets that meet various requirements through various processes. Biopulping is one of the process directions of detergent pulping. The pulp prepared by biopulping has long fibers, high pulp yield, strong resistance to demolition, and the cost per ton of pulp is much lower than that of chemical pulp and mechanical pulp. However, due to the high requirements for the cultivation, selection and pulping conditions of biological strains, there are many problems such as large production fluctuations, uneven material handling, long processing time, and low production efficiency. Biopulping is currently difficult to industrialize.

[0031] Traditional mechanical pulping methods usually require a lot of energy, resulting in high production costs. Energy consumption not only affects economic benefits, but also increases the burden on the environment; at the same time, the pulp processing speed is slow, and the efficiency of enzymatic hydrolysis and mechanical treatment is not high, affecting the overall production efficiency.

[0032] Therefore, the present invention provides a composite bio-enzyme-assisted low-energy pulping method, which aims to solve the problems of high energy consumption and low efficiency in the traditional pulping process. By using composite bio-enzymes such as laccase, cellulase and pectinase, and using ultrasound during the enzymatic hydrolysis process, the activity and enzymatic hydrolysis efficiency of the enzyme can be improved, and the enzymatic hydrolysis efficiency of the raw materials can be enhanced, thereby reducing energy consumption; at the same time, different enzymes are processed and cross-linked in steps to ensure that each enzyme reacts under optimal conditions to increase the reaction efficiency.

[0033] The preparation method of the composite bio-enzyme preparation comprises:

[0034] S110: dispersing laccase in a phosphate buffer solution, adding magnetic particles, performing a first stirring treatment, adding a cross-linking agent, and washing with a phosphate buffer solution after the reaction is completed to obtain a first solvent; preferably, the concentration range of laccase is between 6.0 g / L and 7.0 g / L; the temperature of the first stirring treatment is 3° C. to 6° C., and the use of low-temperature stirring treatment can effectively prevent the thermal inactivation of laccase and ensure its activity stability during the preparation process. The low-temperature treatment reduces the degradation rate of the protein and prolongs the effective activity time of the enzyme, which is beneficial to thermosensitive enzymes and helps to ultimately improve the persistent activity of the composite enzyme preparation;

[0035] S120: dispersing cellulase in a phosphate buffer, adding a first solvent, performing a second stirring treatment, adding a cross-linking agent, and washing with a phosphate buffer after the reaction is completed to obtain a second solvent; preferably, the concentration of cellulose is in the range of 1.0 g / L-5.0 g / L, and the second stirring treatment temperature is 20° C.-25° C.;

[0036] S130: dispersing pectinase in a phosphate buffer, adding a second solvent, performing a third stirring treatment, adding a cross-linking agent, and washing with a phosphate buffer after the reaction is completed to obtain a third solvent; preferably, the concentration range of pectin is between 0.5 g / L and 2 g / L, and the temperature of the third stirring treatment is 20° C.-25° C. At this temperature, the molecular activities of cellulase and pectinase are enhanced, and they can be more fully combined with the substrate, thereby optimizing the enzymatic hydrolysis effect of the composite preparation and enhancing the synergistic effect between the enzyme levels;

[0037] Furthermore, the time of the first stirring treatment, the second stirring treatment and the third stirring treatment is 0.5h-1h, the rotation speed is between 70rpm-120rpm, and the cross-linking agent includes at least one of glutaraldehyde, EDC, and NHS; selecting a stirring time of 0.5h-1h and a rotation speed of 70rpm-120rpm can avoid enzyme structural damage caused by excessive stirring while ensuring uniform dispersion of each enzyme, and can avoid excessive mechanical shear force from damaging the active center of the enzyme, while ensuring that the enzyme is fully combined with the magnetic particles and the cross-linking agent to form a stable composite structure; the cross-linking agent is used to connect different enzymes with the magnetic particles, which can effectively fix the position of the enzyme and prevent it from being lost during use, and glutaraldehyde provides a bifunctional group, which helps to achieve a strong cross-linking effect; EDC and NHS react under specific conditions to generate stable ester bonds or amide bonds, so that the enzyme is fixed on the surface of the magnetic particles, which not only maintains the enzyme activity, but also enhances the recycling capacity of the composite enzyme preparation.

[0038] S140: Clean the third solvent with phosphate buffer to obtain a composite bio-enzyme preparation.

[0039] S100: pre-treating the raw material, adding a composite biological enzyme preparation and a softener, and performing enzymolysis treatment under ultrasound to obtain a mixture;

[0040] Preferably, the pretreatment includes water washing and oxidation treatment. The water washing can remove dust, sand and other impurities on the surface of the raw material, reduce unnecessary pollution in the subsequent process, improve the purity of the slurry, and reduce the soluble substances in the raw material, such as some soluble sugars or inorganic salts, to avoid affecting the activity of the enzyme in the subsequent steps or causing the quality of the slurry to decrease; the oxidation treatment can remove part of the lignin and enhance the exposure of cellulose, thereby improving the enzymatic hydrolysis effect under the condition of low chemical addition, and has environmental advantages;

[0041] The temperature of enzymatic hydrolysis treatment is between 45℃ and 55℃, and the enzymatic activity of the composite biological enzyme preparation can reach a high level. This temperature can ensure the activity of the enzyme while avoiding high energy consumption or enzyme inactivation caused by excessive temperature, thereby ensuring the efficiency of the enzymatic hydrolysis process and accelerating the decomposition process of the enzyme on the raw material;

[0042] The enzymatic treatment time is 2h-3h, which can not only ensure the complete decomposition of the raw material cellulose, hemicellulose and pectin by the composite biological enzyme, but also avoid the waste of enzyme resources or possible fiber degradation caused by long-term enzymatic hydrolysis, so that the fiber structure is partially softened and loosened, making the subsequent mechanical pulping step easier, further reducing energy consumption and improving pulping quality.

[0043] S200: mechanically pulping the mixture, performing a filament separation process through a rubbing and grinding device to form a slurry;

[0044] Preferably, the mass concentration of the slurry is adjusted to 12%-16%. The slurry has a suitable fiber distribution density, can effectively separate fiber bundles during mechanical pulping, helps to obtain uniform slurry, improves the uniformity and quality of the final pulp, and the moderate concentration makes the friction and collision between fibers moderate, can be quickly separated in the mechanical pulping equipment, and reduces the time and energy consumption of mechanical pulping. Too high a concentration will increase the equipment load and wear, while too low a concentration will lead to low pulping efficiency. Therefore, this concentration balances the equipment load and pulping efficiency and extends the service life of the equipment.

[0045] Furthermore, the optimal activity range of the composite bio-enzyme preparation is between pH 5.5 and 6.5. This pH condition ensures the stability and high activity of the enzyme in decomposing cellulose and hemicellulose, further improving the pulping efficiency. At the same time, the fiber structure is relatively stable and will not be damaged due to too low or too high pH value, which is beneficial to maintaining the strength and fiber length of the pulp and improving the physical properties of the final pulp product.

[0046] S300: the pulp is bleached and cleaned to complete the pulping process; wherein the composite bio-enzyme preparation includes laccase, cellulase, pectinase, and magnetic particles.

[0047] Preferably, the bleaching treatment includes a temperature range of 45°C-55°C. The oxidizing ability of hydrogen peroxide is relatively strong, which can more effectively decompose impurities and pigment molecules in cellulose, thereby improving the bleaching effect and making the pulp whiter. The bleaching treatment at this temperature avoids fiber degradation or strength loss that may be caused by high temperature, ensures the physical properties of the slurry, and thus ensures the toughness and strength of the finished pulp. Compared with the bleaching process at a higher temperature, this temperature range is more economical in terms of energy consumption, meets the goal of low energy consumption, and contributes to overall energy saving; the reaction time is 3h-5h Hydrogen peroxide can fully oxidize and decompose impurities and pigment molecules in the pulp under mild conditions to achieve higher bleaching uniformity and stability, avoid excessive oxidation of fibers by hydrogen peroxide, protect the fiber structure, maintain the strength and quality of pulp, and reduce the consumption of hydrogen peroxide. At the same time, it can effectively oxidize the lignin and pigment molecules remaining in the pulp, thereby improving the whiteness of the pulp and reducing the subsequent need to adjust the bleaching degree. In addition, hydrogen peroxide is an environmentally friendly bleaching agent, which eventually decomposes into water and oxygen during the bleaching process, does not produce harmful by-products, and is environmentally friendly.

[0048] Embodiment 1:

[0049] This embodiment provides a composite bio-enzyme-assisted low-energy pulping method, the steps are as follows:

[0050] S100: soaking the raw material in deionized water, making the water flow by mechanical stirring or pumping, washing the raw material for 0.45 hours, then adding oxygen to the washed raw material for oxidation treatment, adding a composite biological enzyme preparation and a softener, performing an enzymatic treatment under ultrasound at a temperature of 50°C for 2.5 hours to obtain a mixture, wherein the softener includes polyvinyl alcohol, CTAC, and starch, and the composite biological enzyme preparation includes laccase: 1%, cellulase: 2%, and pectinase: 0.5%;

[0051] S200: mechanically pulping the mixture, performing a filament separation process through a rubbing and grinding device to form a slurry, wherein the mass concentration of the slurry is 14% and the pH value is 6;

[0052] S300: adding hydrogen peroxide to the pulp, bleaching it at a temperature of 50°C, and then washing it three times to complete the pulping process;

[0053] The preparation method of the composite bio-enzyme preparation is as follows:

[0054] S110: dispersing laccase at a concentration of 6.5 g / L in a phosphate buffer solution, adding iron oxide magnetic particles, performing a first stirring treatment at a temperature of 5° C. and a rotation speed of 100 rpm for 0.8 h, adding glutaraldehyde, and washing with a phosphate buffer solution after the reaction is completed to obtain a first solvent;

[0055] S120: dispersing 3.0 g / L cellulase in a phosphate buffer, adding a first solvent, performing a second stirring treatment at a temperature of 22° C. and a rotation speed of 100 rpm for 0.8 h, adding glutaraldehyde, and washing with a phosphate buffer after the reaction is completed to obtain a second solvent;

[0056] S130: dispersing 1.0 g / L pectinase in a phosphate buffer, adding a second solvent, performing a second stirring treatment at a temperature of 22° C. and a rotation speed of 100 rpm for 0.8 h, adding glutaraldehyde, and washing with a phosphate buffer after the reaction is completed to obtain a third solvent;

[0057] S140: Clean the third solvent with phosphate buffer to obtain a composite bio-enzyme preparation.

[0058] Embodiment 2:

[0059] This embodiment provides a composite bio-enzyme-assisted low-energy pulping method, the steps are as follows:

[0060] S100: soaking the raw material in deionized water, making the water flow by mechanical stirring or pumping, washing for 0.3 hours, then adding ozone to the washed raw material for oxidation treatment, adding a composite biological enzyme preparation and a softener, performing enzymolysis treatment under ultrasound at a temperature of 45°C for 2 hours to obtain a mixture, wherein the softener includes polyvinyl alcohol, CTAC, and starch, and the composite biological enzyme preparation includes laccase: 0.5%, cellulase: 1%, and pectinase: 1%;

[0061] S200: mechanically pulping the mixture, performing a filament separation process through a rubbing and grinding device to form a slurry, wherein the mass concentration of the slurry is 12% and the pH value is 5.5;

[0062] S300: adding hydrogen peroxide to the pulp, bleaching it at 45°C, and then washing it for 5 times to complete the pulping process;

[0063] The preparation method of the composite bio-enzyme preparation is as follows:

[0064] S110: dispersing laccase with a concentration of 6.0 g / L in a phosphate buffer solution, adding iron oxide magnetic particles, performing a first stirring treatment at a temperature of 3° C. and a rotation speed of 700 rpm for 0.5 h, adding EDC, and washing with a phosphate buffer solution after the reaction is completed to obtain a first solvent;

[0065] S120: dispersing 1.0 g / L cellulase in a phosphate buffer, adding a first solvent, performing a second stirring treatment at a temperature of 20° C. and a rotation speed of 70 rpm for 0.5 h, adding EDC, and washing with a phosphate buffer after the reaction is completed to obtain a second solvent;

[0066] S130: dispersing 0.5 g / L pectinase in a phosphate buffer, adding a second solvent, performing a second stirring treatment at a temperature of 20° C. and a rotation speed of 70 rpm for 0.5 h, adding EDC, and washing with a phosphate buffer after the reaction is completed to obtain a third solvent;

[0067] S140: Clean the third solvent with phosphate buffer to obtain a composite bio-enzyme preparation.

[0068] Embodiment three:

[0069] This embodiment provides a composite bio-enzyme-assisted low-energy pulping method, the steps are as follows:

[0070] S100: soaking the raw material in deionized water, making the water flow by mechanical stirring or pumping, washing the raw material for 1 hour, then adding hydrogen peroxide to the washed raw material for oxidation treatment, adding a composite biological enzyme preparation and a softener, performing enzymolysis treatment under ultrasound at a temperature of 55°C for 3 hours to obtain a mixture, wherein the softener includes polyvinyl alcohol, CTAC, and starch, and the composite biological enzyme preparation includes laccase: 5%, cellulase: 5%, and pectinase: 2%;

[0071] S200: mechanically pulping the mixture, performing a filament separation process through a rubbing and grinding device to form a slurry, wherein the mass concentration of the slurry is 16% and the pH value is 6.5;

[0072] S300: adding hydrogen peroxide to the pulp, bleaching it at a temperature of 55°C, and then washing it three times to complete the pulping process;

[0073] The preparation method of the composite bio-enzyme preparation is as follows:

[0074] S110: dispersing laccase with a concentration of 7.0 g / L in a phosphate buffer solution, adding iron oxide magnetic particles, performing a first stirring treatment at a temperature of 6° C. and a rotation speed of 120 rpm for 1 hour, adding NHS, and washing with a phosphate buffer solution after the reaction is completed to obtain a first solvent;

[0075] S120: dispersing 5.0 g / L cellulase in a phosphate buffer, adding a first solvent, performing a second stirring treatment at a temperature of 25° C. and a rotation speed of 120 rpm for 1 hour, adding NHS, and washing with a phosphate buffer after the reaction is completed to obtain a second solvent;

[0076] S130: dispersing 2.0 g / L pectinase in a phosphate buffer, adding a second solvent, performing a second stirring treatment at a temperature of 25° C. and a rotation speed of 120 rpm for 1 hour, adding NHS, and washing with a phosphate buffer after the reaction is completed to obtain a third solvent;

[0077] S140: Clean the third solvent with phosphate buffer to obtain a composite bio-enzyme preparation.

[0078] Comparative Example 1:

[0079] This comparative example provides a bio-enzyme-assisted low-energy pulping method, the steps are as follows:

[0080] S100: soaking the raw material in deionized water, making the water flow by mechanical stirring or pumping, washing the raw material for 1 hour, then adding oxygen to the washed raw material for oxidation treatment, adding laccase and softener, performing enzymolysis treatment under ultrasound at a temperature of 50°C for 2.5 hours to obtain a mixture, wherein the softener includes polyvinyl alcohol, CTAC, and starch;

[0081] S200: mechanically pulping the mixture, performing a filament separation process through a rubbing and grinding device to form a slurry, wherein the mass concentration of the slurry is 16% and the pH value is 6.5;

[0082] S300: hydrogen peroxide is added to the pulp, bleaching treatment is performed at a temperature of 55°C, and then washing treatment is performed three times to complete the pulping process.

[0083] Comparative Example 2:

[0084] This comparative example provides a composite bio-enzyme-assisted low-energy pulping method, the steps are as follows:

[0085] S100: soaking the raw material in deionized water, making the water flow by mechanical stirring or pumping, washing the raw material for 1 hour, then adding oxygen to the washed raw material for oxidation treatment, adding composite biological enzymes and softeners, performing enzymolysis treatment under ultrasound at a temperature of 50°C for 2.5 hours to obtain a mixture, wherein the softener includes polyvinyl alcohol, CTAC, starch, and the composite biological enzyme includes laccase: 1%, cellulase: 2%, pectinase: 0.5% and the rest is mixed with water;

[0086] S200: mechanically pulping the mixture, performing a filament separation process through a rubbing and grinding device to form a slurry, wherein the mass concentration of the slurry is 16% and the pH value is 6.5;

[0087] S300: hydrogen peroxide is added to the pulp, bleaching treatment is performed at a temperature of 55°C, and then washing treatment is performed three times to complete the pulping process.

[0088] Performance Testing:

[0089] The performance tests of Examples 1 to 3 and the comparative example were carried out in accordance with the national standards. The basis weight of the hand sheet was 70 g / m 2 , according to the national standard (GB / T451.2-2002), the actual quantitative weight of the paper sheets was weighed and the whiteness was measured according to the national standard GB / T7974-2013; the pulp tearing index was measured according to the national standard GB / T455-2002; the tensile index was measured according to the national standard GB / T453-2002. At the same time, the pulping power consumption was recorded and the pulping rate was calculated, as shown in Table 1:

[0090] Table 1

[0091] project Pulping power consumption (kWh / t) Pulp yield (%) Whiteness(%ISO) Embodiment 1 855 95.5 49.26 Embodiment 2 946 94.2 47.65 Embodiment 3 904 94.8 48.55 Comparative Example 1 1256 86.8 45.65 Comparative Example 2 1045 90.56 46.65

[0092] As can be seen from the above table, the power consumption and pulp yield in the slurry preparation process of the embodiment are significantly different from those of the comparative example, while the whiteness has no significant change, indicating that the synergistic effect of multiple enzymes in the composite bio-enzyme preparation can significantly reduce power consumption.

[0093] The mechanical properties of the paper products prepared in Examples 1 to 3 and Comparative Examples 1 to 2 were measured, and the results are shown in Table 2:

[0094] Table 2

[0095]

[0096]

[0097] As can be seen from the above table, the tensile index and ring crush index of the paper prepared in the embodiment are much higher than those of the paper in the comparative example. The paper prepared in the embodiment has a significantly higher tensile index, indicating that the pulping method makes the fibers more tightly bound and the structure more tough, which is due to the synergistic effect of cellulase and pectinase in the composite enzyme preparation, which can effectively degrade impurities between fibers and promote the enhancement of fiber binding force; the ring crush index of the embodiment is higher, which means that the paper prepared by the method is better in pressure resistance and durability, because the layered fixation technology makes various enzymes (laccase, cellulase, pectinase) more evenly distributed on the fiber surface and more durable, thereby improving the adhesion of the fiber and the structural strength of the paper; through layered fixation, different enzymes in the composite biological enzyme preparation can act on the fiber in sequence under suitable conditions, avoiding mutual interference between enzymes and improving the catalytic efficiency of the enzyme, which makes the enzymatic hydrolysis and pulping in the embodiment more efficient and more effective, so that the performance of embodiments one to three far exceeds that of comparative example two.

[0098] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A composite bio-enzyme-assisted low-energy pulping method, characterized in that: The method comprises: S100: pre-treating the raw material, adding a composite biological enzyme preparation and a softener, and performing enzymolysis under ultrasound to obtain a mixture; S200: mechanically pulping the mixture, performing a fiber separation process through a rubbing and grinding device to form a slurry; S300: bleaching and cleaning the pulp to complete the pulping process; Wherein, the composite biological enzyme preparation comprises laccase, cellulase, pectinase and magnetic particles.

2. The method according to claim 1, characterized in that In step S100, the method for preparing the composite bio-enzyme preparation includes: S110: dispersing the laccase in a phosphate buffer solution, adding magnetic particles, performing a first stirring treatment, adding a cross-linking agent, and washing with a phosphate buffer solution after the reaction is completed to obtain a first solvent; S120: dispersing the cellulase in a phosphate buffer, adding the first solvent, performing a second stirring treatment, adding the cross-linking agent, and washing with a phosphate buffer after the reaction is completed to obtain a second solvent; S130: dispersing the pectinase in a phosphate buffer, adding the second solvent, performing a third stirring treatment, adding the cross-linking agent, and washing with a phosphate buffer after the reaction is completed to obtain a third solvent; S140: Clean the third solvent with phosphate buffer to obtain the composite bio-enzyme preparation.

3. The method according to claim 2, characterized in that In step S110, the concentration of the laccase is in the range of 6.0 g / L-7.0 g / L; and / or In step S110, the first stirring treatment temperature is between 3°C and 6°C; and / or In step S120, the concentration of cellulose is in the range of 1.0 g / L-5.0 g / L; and / or In step S120, the second stirring treatment temperature is between 20°C and 25°C; and / or In step S130, the concentration of pectin is in the range of 0.5 g / L-2.0 g / L; and / or In step S130, the third stirring treatment temperature is between 20°C and 25°C; and / or The time of the first stirring treatment, the second stirring treatment and the third stirring treatment is between 0.5h-1h; and / or The rotation speeds of the first stirring process, the second stirring process and the third stirring process are between 70 rpm and 120 rpm; and / or The cross-linking agent includes at least one of glutaraldehyde, EDC and NHS.

4. The method according to claim 1, characterized in that In step S100, The pretreatment includes: water washing and oxidation treatment; and / or The temperature of the enzymatic treatment is between 45°C and 55°C; and / or The time of the enzymatic hydrolysis treatment is between 2h and 3h.

5. The method according to claim 1, characterized in that In step S200, The mass concentration of the slurry is adjusted between 12% and 16%; and / or The pH value of the slurry is between 5.5 and 6.

5.

6. The method according to claim 1, characterized in that In step S300, the bleaching treatment includes adding hydrogen peroxide to the slurry at a temperature range of 45°C-55°C to react for 3h-5h.

7. The method according to claim 1, characterized in that In the step S100, the softener includes at least one of polyvinyl alcohol, CTAC, and starch.

8. The method according to claim 1, characterized in that In the composite bio-enzyme preparation, the mass percentages of the components are: the laccase: 0.5%-5%, the cellulase: 1%-5%, and the pectinase: 0.5%-2%.

9. The method according to claim 8, characterized in that In the composite bio-enzyme preparation, the mass percentages of the components are: laccase: 1%, cellulase: 2%, and pectinase: 0.5%.

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