20 results about "Pulp bleaching" patented technology

The invention provides bamboo reed bleached fluff pulp as well as a preparation method and application thereof, and belongs to the field of papermaking. According to the characteristics of low bonding strength and small bursting strength of the arundo donax short fibers and parenchyma cells, the use of chemicals such as a debonding agent and the like is canceled, the preparation process is different from a traditional bamboo fluff pulp preparation process, the components of the arundo donax short fibers are reserved, the three-dimensional structure of the arundo donax bleached fluff pulp fibers is optimized, the water absorption and water retention capacity of the fluff pulp is improved, and meanwhile, the paper pulp yield is optimized. According to the raw material characteristics of the bamboo reed, the process conditions of prehydrolysis, cooking and bleaching are optimized, and an economical and efficient bleached fluff pulp product of the bamboo reed pulp is produced, so that the method has good practical application value.

The application discloses a pulp bleaching method based on electric field gradient coupling oxygen nucleus. The method comprises the following steps: adding pulp into a reaction kettle, adding alkali and a protective agent, stirring and mixing, and heating; when the temperature is heated to 90-100 DEG C, the temperature is kept, a direct current electric field is applied to the reaction kettle and oxygen is introduced under high-speed stirring, and reaction is carried out for 3-5 min; reaction is carried out for 30-120 min under low-speed stirring. The method solves the problems of low reaction efficiency and low oxygen utilization rate in the existing oxygen delignification process. By applying a direct current electric field to the outer wall of the reaction kettle, the oxygen molecules are separated by the electric field force, and the combination ability with the surface of the pulp fiber is improved. The method significantly improves the removal efficiency of lignin, and significantly improves the pulp brightness and Kappa number. The application is suitable for the field of pulping and papermaking, and has important significance for the bleaching process with high environmental protection requirements.

The invention provides a composite metal catalyst and application thereof in biological combined light treatment paper pulp bleaching. The method comprises the following steps: dividing and brooming cooked paper pulp fibers by adopting biological pretreatment, and then carrying out illumination bleaching under simulated sunlight irradiation by adopting a metal photocatalyst (ZnO, ZFO, ZAO, ZMO and the like). According to the mild treatment method, the whiteness of the paper pulp is improved, and meanwhile it is guaranteed that fibers are not damaged. Compared with traditional chemical bleaching, biological combined light treatment bleaching has the advantages that the content of pollutants in wastewater is greatly reduced, meanwhile, reacted metal oxides can be recycled, and the combined treatment method can be used as a novel paper pulp fiber bleaching mode.

The application belongs to the technical field of bioengineering, and particularly relates to a high-temperature-resistant laccase mutant obtained by site-directed mutation through an overlapping PCR technique, and preparation and application thereof. The laccase mutant is obtained on the basis of a wild-type laccase shown in SEQ ID NO. 1, and at least one of D221Y, E231D, Y441H or Y441F mutations occurs, and the mutant enzyme activity and the thermal stability at 80 DEG C are both improved to different degrees relative to the wild type, which is beneficial to expand the application in the industrial fields of degrading lignocellulose, paper pulp bleaching and the like.

The utility model relates to the technical field of paper pulp bleaching, and discloses a hydrogen peroxide supply device for a wood pulp bleaching process, which comprises an oxygen generator, a water purifier, a liquid caustic soda pressure stabilizing and filtering system, a hydrogen peroxide electrolysis production system, an energy storage system and the like. And an alkaline hydrogen peroxide storage tank is arranged on the outer side of the hydrogen peroxide electrolysis production system. According to the hydrogen peroxide supply device for the wood pulp bleaching process, in order to better control the flow of alkaline hydrogen peroxide, high-purity oxygen is stably supplied through the oxygen generator, and the liquid caustic soda pressure is stabilized and impurities are filtered through the liquid caustic soda pressure stabilizing and filtering device, so that the stable quality of the generated alkaline hydrogen peroxide is ensured; the alkaline hydrogen peroxide outlet flow meter and the alkaline hydrogen peroxide discharging pump work cooperatively, the flow of the alkaline hydrogen peroxide can be accurately controlled according to actual requirements, accurate supply is achieved, and the problem that the bleaching effect is unstable due to fluctuation of the dosage of the hydrogen peroxide is solved.

The invention relates to the field of pulping and papermaking, in particular to a mediator-free laccase delignification bamboo pulp bleaching method which comprises the following steps: S1, mixing laccase and absolute dry pulp, adjusting pulp concentration, introducing oxygen at a certain temperature for reaction, washing with deionized water, spin-drying and scattering; the absolutely dry pulp is obtained by defibering, screening and drying unbleached chemical bamboo pulp. And S2, carrying out acid pickling chelation on the absolutely dry slurry treated in the step S1. And S3, bleaching the absolutely dry slurry treated in the step S2. According to the method, the lignin in the bamboo pulp is efficiently removed, the kappa number is reduced by more than 40%, the biological enzyme is directly used for replacing about 30% of total chemicals under the condition of not changing the section of an oxygen removal tower in the original process, and the consumption of chemicals and the discharge of bleaching wastewater in industrial production are reduced; and meanwhile, no expensive mediator is added, so that the problem of corrosion of the mediator to equipment is avoided, and the maintenance cost is greatly reduced.

The present invention addresses the problem of providing packaging paper having satisfactory printability and a satisfactory "stiffness feeling".　The problem is solved by packaging paper comprising a paper substrate containing pulp and at least one coating layer on at least one surface of the paper substrate, wherein: the at least one coating layer contains a white inorganic pigment and a binder; the total content of pulp selected from the group consisting of unbleached softwood kraft pulp, bleached softwood kraft pulp, unbleached hardwood kraft pulp, and bleached hardwood kraft pulp in the paper substrate is 70 mass% or more relative to the total mass of pulp contained in the paper substrate; the thickness of the packaging paper is 70-170 μm; and the relationship between the elastic modulus A (MPa) in the cross direction (CD) of the packaging paper and the thickness B (μm) of the packaging paper satisfies A / B = 18 to 55.

The invention discloses a laccase mutant and application thereof, the mutant is obtained by mutating wild laccase BstCotA from bacillus subtilis, the amino acid sequence of the mutant is as shown in SEQ ID NO.1, and the mutant is mutated into at least one of E186A, N65G, D185G and N311G. The invention further discloses a preparation method of the laccase mutant. Compared with a wild type, the mutant has the advantages that the catalytic activity is obviously improved, and the relative enzyme activity is higher under the conditions that the temperature is 37 DEG C and the pH value is 5.0; the pH stability and the thermal stability are enhanced, and the activity in the range of 40-90 DEG C exceeds 75%; the dye decolorization efficiency is higher, the decolorization rate of amino black 10B reaches 28%-35%, the decolorization rate of crystal violet reaches 35%-45%, and complex printing and dyeing wastewater can be efficiently treated; the lignin degradation capacity is better, the degradation rates within 1 hour and 2 hours are higher than those of the wild type, and pulping bleaching and biomass resource utilization are facilitated.

The utility model relates to the technical field of bleaching equipment, and discloses paper pulp bleaching equipment which is characterized in that a stirring rod is arranged in a tank body, and a main rod of the stirring rod is designed to be a rectangular rod; a telescopic assembly is arranged at the top of the tank body and comprises a rod body, the bottom end of the rod body penetrates through the top of the tank body and is rotationally connected with the tank body, and a stirring rod penetrates through the rod body; the first bevel gear is fixedly arranged on the outer side wall of the rod body in a sleeving mode. The motor I is arranged at the top of the tank body; the bevel gear II is arranged on an output shaft of the motor I and is meshed with the bevel gear I; the top plate is arranged at the top of the stirring rod; according to the bleaching equipment, the telescopic assembly drives a first bevel gear and a second bevel gear to be engaged through a first motor to drive a stirring rod to rotate, meanwhile, a second motor drives an extrusion block to move the stirring rod up and down, and the mixing effect of the stirring rod is improved. According to the bleaching equipment, the protection assembly can shield and protect the exposed part of the assembly through the guardrail, and mistaken touch of workers is avoided.

The invention belongs to the technical field of preservative paper preparation, and particularly relates to composite antibacterial preservative packaging paper as well as a preparation method and application thereof. The preparation method of the composite antibacterial fresh-keeping packaging paper comprises the following steps: firstly, mixing and pulping bleached bamboo pulp and broadleaf wood chemithermomechanical pulp, adding aluminum sulfate, rosin size, a wet strength agent PAE and sodium hexametaphosphate, and performing papermaking and forming; then, essential oil is added into starch gelatinization liquid composed of oxidized corn starch and an epsilon-polylysine hydrochloride solution, a fresh-keeping coating emulsion is obtained through emulsification, and finally, the composite antibacterial fresh-keeping packaging paper is obtained through coating and drying. According to the composite antibacterial fresh-keeping packaging paper disclosed by the invention, fresh-keeping coated paper is prepared by adopting the natural antibacterial agent, the bamboo pulp fiber and other raw materials and matching with the oxidized corn starch through a specific process, and the composite antibacterial fresh-keeping packaging paper has the characteristics of bacteriostasis, environmental friendliness and stability and safety in use, can be used as fresh-keeping packaging paper or fresh-keeping packing paper, effectively delays the decay of various fruits, and is suitable for being used in multiple scenes; the invention also provides a preparation method thereof.

The invention belongs to the field of clean production of paper pulp bleaching in pulping and papermaking industries, and discloses an AOX reduction agent for a chlorine dioxide paper pulp bleaching section and application of the AOX reduction agent. The agent for AOX reduction in the chlorine dioxide paper pulp bleaching section comprises an agent A and an agent B. The agent A comprises at least one of micromolecular organic acid A1 and aminocarboxylic acid A2. And the agent B is peroxy acid salt. An agent A and an agent B are added at the same time in acidic and heated chlorine dioxide bleaching sections, carbon center free radicals with dehalogenation activity are generated in situ, the free radicals selectively break C-Cl bonds of organic halides through a single electron transfer mechanism, chlorine atoms are converted into chloride ions, and therefore in-situ removal of AOX is achieved. According to the AOX decrement agent and the application method thereof provided by the invention, the generation amount of AOX can be obviously reduced by 55-80%, and the whiteness and viscosity of paper are not sacrificed.

The invention belongs to the technical field of pulping and papermaking, and discloses a paper pulp hydrogen peroxide bleaching accelerant with a nitrilotriacetic acid metal complex as an active component and an application method of the paper pulp hydrogen peroxide bleaching accelerant. The bleaching promoting agent is a mixture of a nitrilotriacetic acid metal complex and free nitrilotriacetic acid salt; according to the amount of substance, the ratio of the nitrilotriacetic acid metal complex to the free nitrilotriacetic acid salt is 1: (R1), and R is 7.8-1000. The obtained complex not only can catalyze hydrogen peroxide to continuously generate. OH and singlet oxygen (O2), but also can continuously output active oxygen and improve oxidation selectivity due to the fact that the consumption rate of the complex to. OH is low, so that the paper pulp bleaching efficiency is remarkably improved, the use amount of hydrogen peroxide can be effectively reduced, and degradation of pulp fibers is reduced.

This utility model discloses a static sulfuric acid dilution system for pulping and bleaching, including a static diluter and a medium-consistency riser. One side of the static diluter is equipped with a process water injection nozzle and a sulfuric acid injection nozzle, while the other side has a discharge port. The process water injection nozzle is connected to a process water inlet pipe, which is equipped with a process water flow meter and a process water regulating valve. The sulfuric acid injection nozzle is connected to a sulfuric acid feed pipe, which is equipped with a concentrated sulfuric acid on / off valve, a concentrated sulfuric acid flow meter, and a concentrated sulfuric acid regulating valve. A dilute sulfuric acid injection nozzle is located above the medium-consistency riser and is connected to the discharge port of the static diluter via a dilute sulfuric acid pipe. The bottom of the medium-consistency riser is connected to a pulp conveying pipe. This utility model effectively monitors the sulfuric acid dilution process, ensuring stable system operation and data accuracy, achieving automated operation, improving dilution efficiency, reducing operational risks, and can be designed with a modular structure for easy installation, maintenance, and expansion.

The invention discloses laccase and application thereof, and belongs to the field of bioengineering. The high-activity laccase Lac-11 is obtained through database mining, and compared with existing high-activity laccase BstCotA, the high-activity laccase Lac-11 has the following beneficial effects that 1, the enzyme activity is remarkably improved, the enzyme activity is improved by nearly 50% under the conditions that the temperature is 37 DEG C and the pH is 5.0, and the industrial enzyme cost is reduced; 2, the pH stability is higher, the enzyme activity retention rate is higher in the pH range of 5.0-8.0, and the method is suitable for wider acid-base environments. And 3, the thermal stability is better, the stability at the medium-high temperature interval of 50-80 DEG C is obviously higher than that of a control enzyme, and the method is suitable for an industrial high-temperature process. 4, the dye decolorization efficiency is higher, the decolorization rates of amino black 10B and crystal violet respectively reach 31% and 37%, and printing and dyeing wastewater can be efficiently treated. And 5, the lignin degradation capacity is outstanding, the degradation rates within 1 hour, 2 hours and 24 hours are 22%, 25% and 58% respectively, and pulping bleaching and biomass recycling are facilitated.

The invention relates to the technical field of biological enzyme screening, in particular to a method for high-throughput screening of pulp bleaching-assisting xylanase. The method comprises the following steps: preparing a paper tray substrate with a specific specification; the method comprises the following steps: reacting a sample containing xylanase to be screened with a paper tray in a buffer solution with the pH value of 6.0 at 50 DEG C for 3 hours; after the reaction, removing enzyme liquid and a product, washing the paper tray, adding 2 mM of KMnO4 solution, reacting for 3 minutes, and measuring a 546 nm light absorption value; and by combining positive control and negative control, evaluating the bleaching assisting capability of the xylanase through the KMnO4 reaction rate. According to the method, oxidation of a subsequent bleaching agent on lignin is promoted through simulated enzyme treatment, the reduction rate of the light absorption value can indirectly reflect the improvement degree of enzyme treatment on the bleaching property of the paper pulp, and then rapid and high-throughput screening is achieved.

The utility model relates to the technical field of paper pulp bleaching, and discloses a hydrogen peroxide galvanic pile test platform, which comprises a frame, moving wheels are arranged at the lower end of the frame, hydrogen peroxide electrolysis equipment is arranged in the frame, the hydrogen peroxide electrolysis equipment comprises an oxygen low-pressure tank, and the oxygen low-pressure tank is connected with the moving wheels. An oxygen low-pressure tank is fixedly installed on the surface of the frame, and a pipeline is fixedly connected to the side surface of the oxygen low-pressure tank. According to the hydrogen peroxide galvanic pile test platform, alkaline hydrogen peroxide generated by the cathode can be effectively collected and utilized as a product, a sodium hydroxide solution discharged by the anode can be used in a bleaching process, waste of chemical raw materials is reduced, and oxygen is collected into the oxygen low-pressure tank through an oxygen circulation process; after being pressurized by the oxygen compressor, the oxygen is mixed with fresh oxygen and participates in cathode side reaction again, so that the cyclic utilization of oxygen resources is realized, the production cost is reduced, and the resource utilization efficiency of the whole system is improved.

The invention relates to the technical field of pulping of grass plant fiber raw materials, and particularly discloses a cotton stalk pulp bleaching process which comprises the following steps: S1, taking neutral cotton stalk pulp which is not bleached; s2, first-stage bleaching: mixing the cotton stalk pulp with a first-stage bleaching agent and water, heating to 60 + / -5 DEG C, and keeping the temperature for 65-95 minutes; the first-stage bleaching agent is prepared from 0.8 to 1.4 percent of a chlorine dioxide agent A and 1.2 to 1.6 percent of a chlorine dioxide agent B; s3, second-stage bleaching: mixing the pulp after the first-stage bleaching with a second-stage bleaching agent and water, heating to 60 + / -5 DEG C, and keeping the temperature for not less than 60 minutes; the second-stage bleaching agent comprises 0.5%-1.0% of a chlorine dioxide agent A and 0.8%-1.2% of a chlorine dioxide agent B; s4, uniformly mixing the slurry subjected to second-stage rinsing with water, 1.8-2.2% of sodium hydroxide, 1.5-4.0% of hydrogen peroxide, 1.3-1.7% of sodium silicate and 4.5-5.5% of magnesium sulfate in a container, heating to 60 + / -5 DEG C, and keeping the temperature for 55-65 minutes; the mass concentration of the slurry in the steps S2-S4 is 8-12%. The scheme is used for solving the problems that the bleaching process of the cotton stalk pulp is complicated and the whiteness after bleaching cannot reach 80% at present.

The invention belongs to the technical field of paper pulp bleaching and heavy metal recycling, and discloses a catalyst for catalyzing alkaline hydrogen peroxide paper pulp bleaching and application of the catalyst. The preparation method of the catalyst comprises the following steps: reacting a wood-based material with acrylonitrile to graft cyano groups on the surface, and then adding the wood-based material into a mixed aqueous solution of hydroxylamine hydrochloride and sodium hydroxide to react to graft amidoxime groups on the surface to obtain an amidoxime group modified wood-based material; the wood-based material is soaked in a solution containing cobalt salt for an adsorption reaction, and the catalyst is obtained. When the catalyst is used for catalyzing alkaline hydrogen peroxide paper pulp bleaching, the ISO (International Standardization Organization) whiteness of hydrogen peroxide bleached section paper pulp can be improved by 25-30%; the wood modified by amidoxime adsorbs cobalt ions in wastewater again, so that the service life of the catalyst is prolonged, the economical efficiency of the catalyst is improved, the environmental risk of heavy metal emission is effectively prevented, and the dual purposes of environmental protection and efficient paper pulp bleaching are achieved.

A method for predicting the chemical oxygen demand (COD) load in a wastewater treatment process associated with a pulping process is disclosed. The pulping process comprises a pulp bleaching process wherein a wastewater stream is obtained from the pulp bleaching process and sent to a wastewater treatment process wherein the wastewater treatment process comprises a primary treatment stage and a secondary treatment stage. The method may include obtaining a value of at least one parameter of the pulp bleaching process, where the parameter is indicative of a COD concentration in the wastewater stream, determining a predicted COD concentration and / or a load in the wastewater stream after a primary treatment stage and / or after a secondary treatment stage based on the value of the at least one parameter of the pulp bleaching process, and determining the COD concentration and / or the load in the wastewater stream after the primary treatment stage and / or after the secondary treatment stage based on the determined predicted COD concentration and / or the load. And providing control information for controlling the wastewater treatment process based on the predicted COD concentration and / or load in the wastewater stream after the primary treatment stage and / or after the secondary treatment stage.