阅读说明：本技术 一种用于针叶木浆的高速切断方法 (High-speed cutting method for softwood pulp ) 是由 许在亮 吕亮 侯发财 许燕飞 徐岩 于 2020-07-24 设计创作，主要内容包括：本发明提供了一种用于针叶木浆的高速切断方法。该技术方案首先利用纤维素酶和半纤维素酶对润湿的针叶木浆进行酶解,在酶解后半段,利用椰油酰胺丙基甜菜碱增进物料表面张力,保持酶解速率；在此基础上,将酶解后的产物在3个大气压、134℃条件下蒸煮20min,再反复冻融8次,使其纤维的韧性及交联性得到破坏；而后,在鼓风干燥机中以180℃、7m/s的风速鼓风干燥8h,再依次利用双轴撕碎机、水力碎浆机、磨浆机进行处理,最终实现对针叶木浆的切断和均质化处理。本发明可使针叶木浆得到有效切断,使其纤维的分散性得到提高,不仅便于后续抄纸,而且纸张的韧性和抗拉强度更高,具有突出的技术优势。(The invention provides a high-speed cutting method for softwood pulp. According to the technical scheme, firstly, cellulase and hemicellulase are utilized to carry out enzymolysis on wet softwood pulp, and in the latter half period of enzymolysis, cocamidopropyl betaine is utilized to increase the surface tension of materials and keep the enzymolysis rate; on the basis, the product after enzymolysis is cooked for 20min under the conditions of 3 atmospheric pressure and 134 ℃, and then is repeatedly frozen and thawed for 8 times, so that the toughness and the crosslinking property of the fiber are damaged; and then, the softwood pulp is subjected to blast drying for 8 hours in a blast dryer at the temperature of 180 ℃ and the wind speed of 7m/s, and then is treated by a double-shaft shredder, a hydrapulper and a refiner in sequence, and finally the cutting and homogenization treatment of the softwood pulp is realized. The invention can effectively cut off the softwood pulp, improves the fiber dispersibility, is convenient for subsequent papermaking, has higher toughness and tensile strength, and has outstanding technical advantages.)

1. A high speed chopping process for softwood pulp characterized by the steps of:

1) mixing 200 parts by weight of softwood pulp with 300 parts by weight of water, uniformly mixing in a double cone mixer, draining, mixing cellulase to a final concentration of 520U/mL and hemicellulase to a final concentration of 260U/mL, adjusting the pH value to 5.8 by using HCl, keeping the pH value at 35 ℃ for 6 hours, adding 120 parts by weight of water and 20 parts by weight of cocamidopropyl betaine, and keeping the pH value for 4 hours;

2) centrifuging the product obtained in the step 2), taking a solid phase, dispersing the solid phase into 400 parts by weight of water, cooking for 20min under the conditions of 3 atmospheric pressures and 134 ℃, then recovering to normal pressure and naturally cooling to room temperature to obtain a cooked product; repeatedly freezing and thawing the cooked product for 8 times, and then recovering to normal temperature;

3) putting the product obtained in the step 3) into a forced air drying box, and carrying out forced air drying for 8 hours at the temperature of 180 ℃ and the wind speed of 7 m/s; taking out, treating with a double-shaft shredder, treating with a hydrapulper, and pulping with a pulping machine.

2. The high speed chopping method for softwood pulp according to claim 1, characterized in that in step 1), after the cocamidopropyl betaine is added, 220U/mL xylanase is added and then kept for 4 h.

3. The method for high-speed cutting of softwood pulp according to claim 1, wherein in step 1), the ultrasonic agitation is continued during the 4h continuous holding.

4. The high speed chopping method for softwood pulp according to claim 1, wherein in step 2), the upper temperature limit of the freeze-thaw process is 4 ℃ and the lower temperature limit is-5 ℃; the total duration of each freeze-thaw process does not exceed 5 min.

5. The high speed cutting method for softwood pulp according to claim 1, wherein in step 2) the solid phase is dispersed in 400 parts by weight of water by means of a blender.

6. A high speed chopping process for softwood pulp according to claim 1 characterised in that in step 3) the refiner is operated at a speed of not less than 3500 rpm.

7. The high speed chopping method for softwood pulp as recited in claim 1, wherein in step 3), the moisture content of the material after 8 hours of forced air drying is not higher than 2%.

Technical Field

The invention relates to the technical field of pulping and papermaking, in particular to a high-speed cutting method for softwood pulp.

Background

Since pulp fibers are strong and elastic, if the pulp is used for papermaking without any treatment, the pulp fibers are difficult to be uniformly distributed during formation on a wire, and the hardness of the paper to be produced is low, the pulp needs to be sufficiently cut and uniformly mixed before papermaking, and this process is called beating or beating. In addition, the pulp which is not pulped still contains unseparated fiber bundles which are stiff, too long, too thick and lack the necessary cutting and separation, and if the pulp is made of the fiber bundles, the obtained product is loose, porous, rough in surface and low in strength, and cannot meet the use requirements. The paper produced by the pulping paper pulp has compact and uniform tissue and higher strength.

In the beating process, the fibers are sheared, kneaded, carded and the like by a machine part, and meanwhile, the cell walls of the fibers are subjected to displacement, deformation, cracking and other phenomena to absorb water and swell to generate fine fibers, so that the paper pulp has softness and plasticity, the hydroxyl in the cellulose molecular chain is increased to be combined with hydrogen chains, and the binding force among the fibers is improved. According to the beating action, the method can be divided into sticky beating and free beating. The free beating is mainly cutting, and the concentration of paper pulp is lower. The beating machine of the method has sharper blades and dense pitch of the blades, and the fibers are easy to cut off during beating, so that the made paper has the characteristics of small density, bulkiness, opacity, small elasticity, easy adhesion of ink and the like. At present, conventional free pulping has a good effect when processing hardwood pulp; compared with hardwood pulp, softwood pulp has longer fibers and stronger toughness, and the conventional pulping method has generally unsatisfactory cutting effect.

Disclosure of Invention

The invention aims to provide a high-speed cutting method for softwood pulp aiming at the technical defects of the prior art, so as to solve the technical problem that the conventional pulping method has poor cutting effect on the softwood pulp in the prior art.

In order to achieve the technical purpose, the invention adopts the following technical scheme:

a high speed chopping process for softwood pulp comprising the steps of:

1) mixing 200 parts by weight of softwood pulp with 300 parts by weight of water, uniformly mixing in a double cone mixer, draining, mixing cellulase to a final concentration of 520U/mL and hemicellulase to a final concentration of 260U/mL, adjusting the pH value to 5.8 by using HCl, keeping the pH value at 35 ℃ for 6 hours, adding 120 parts by weight of water and 20 parts by weight of cocamidopropyl betaine, and keeping the pH value for 4 hours;

2) centrifuging the product obtained in the step 2), taking a solid phase, dispersing the solid phase into 400 parts by weight of water, cooking for 20min under the conditions of 3 atmospheric pressures and 134 ℃, then recovering to normal pressure and naturally cooling to room temperature to obtain a cooked product; repeatedly freezing and thawing the cooked product for 8 times, and then recovering to normal temperature;

3) putting the product obtained in the step 3) into a forced air drying box, and carrying out forced air drying for 8 hours at the temperature of 180 ℃ and the wind speed of 7 m/s; taking out, treating with a double-shaft shredder, treating with a hydrapulper, and pulping with a pulping machine.

Preferably, in step 1), after adding the cocamidopropyl betaine, 220U/mL xylanase is added and then kept for 4 h.

Preferably, in step 1), the ultrasonic oscillation is continuously performed during the continuous keeping for 4 hours.

Preferably, in the step 2), the upper temperature limit of the freeze thawing process is 4 ℃, and the lower temperature limit is-5 ℃; the total duration of each freeze-thaw process does not exceed 5 min.

Preferably, in step 2), the solid phase is dispersed in 400 parts by weight of water, and this is carried out using a stirrer.

Preferably, in step 3), the rotation speed of the refiner is not lower than 3500 rpm.

Preferably, in the step 3), the water content of the material after 8 hours of air drying is not higher than 2%.

The invention provides a high-speed cutting method for softwood pulp. According to the technical scheme, firstly, cellulase and hemicellulase are utilized to carry out enzymolysis on wet softwood pulp, and in the latter half period of enzymolysis, cocamidopropyl betaine is utilized to increase the surface tension of materials and keep the enzymolysis rate; on the basis, the product after enzymolysis is cooked for 20min under the conditions of 3 atmospheric pressure and 134 ℃, and then is repeatedly frozen and thawed for 8 times, so that the toughness and the crosslinking property of the fiber are damaged; and then, the softwood pulp is subjected to blast drying for 8 hours in a blast dryer at the temperature of 180 ℃ and the wind speed of 7m/s, and then is treated by a double-shaft shredder, a hydrapulper and a refiner in sequence, and finally the cutting and homogenization treatment of the softwood pulp is realized. The invention can effectively cut off the softwood pulp, improves the fiber dispersibility, is convenient for subsequent papermaking, has higher toughness and tensile strength, and has outstanding technical advantages.

Detailed Description

Hereinafter, specific embodiments of the present invention will be described in detail. Well-known structures or functions may not be described in detail in the following embodiments in order to avoid unnecessarily obscuring the details. Approximating language, as used herein in the following examples, may be applied to identify quantitative representations that could permissibly vary in number without resulting in a change in the basic function. Unless defined otherwise, technical and scientific terms used in the following examples have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.