A method for producing refined cotton with high efficiency, environmental protection and energy saving

Abstract

The present invention relates to a method for producing refined cotton in an efficient, environmentally friendly and energy-saving manner, comprising the following steps: S1, selecting high-quality cotton linters; S2, preparing a cooking liquid: the main components of the cooking liquid include sodium hydroxide and water, and the cooking aids include ethanol, biological enzymes, hydrogen peroxide, and a regulator; the proportion of sodium hydroxide to cotton linters is 30-40%, the proportion of water to cotton linters is 40-50%, the proportion of ethanol to cotton linters is 10-15%, the proportion of biological enzymes to cotton linters is 9-12%, the proportion of hydrogen peroxide to cotton linters is 8-10%, and the proportion of the regulator to cotton linters is 3-6%; the use steps of the cooking liquid: a, large liquid ratio penetration: using alkali liquid with a ratio of 1:4 of cotton linters to cooking liquid to penetrate cotton linters, b, small liquid ratio cooking: using a ratio of 1:2 of cotton linters to cooking liquid to perform small liquid ratio alkali cooking of cotton linters, c, hydrogen peroxide bleaching. The alkali liquid cooking process of the cotton linters of the present invention is not only optimized, but also has achieved remarkable results in terms of environmental protection and efficiency.

Description

Technical Field

[0001] The invention relates to the technical field of refined cotton production, and in particular to a method for producing refined cotton with high efficiency, environmental protection and energy saving. Background Art

[0002] Refined cotton is a white flocculent material that is uniform and loose, free of wood chips, bamboo chips, sand, oil, metal objects and other impurities. Its raw material is cotton linters, and its main chemical components are cellulose, lignin and hemicellulose. It is composed of three elements: carbon, hydrogen and oxygen. The mass ratio of its composition is: carbon 44.4%, hydrogen 6.17%, oxygen 49.39%. Its density is generally L50-L56g / cm, and its specific heat capacity is L3O-L40kJ / (kg·℃). It is soluble in copper ammonia solution and has good hydrophilicity and good adsorption. The general formula of refined cotton is: (C6H1005)n. n represents the degree of polymerization of cellulose, which explains the repeated basic chain segments in the cellulose macromolecules-glucose residues. The number of glucose residues contained in the cellulose macromolecules is called the degree of polymerization of cellulose. The degree of polymerization of cotton fiber is generally 10000-15000.

[0003] The existing production method of refined cotton generally includes steaming and rinsing to remove impurities, wax, pectin and other non-cellulose substances in the cotton lint; The current lye cooking effect is relatively poor, the reaction time between the lye and the cotton lint is long, and the lye cannot fully penetrate the cotton lint, resulting in the preparation of refined cotton failing to meet the requirements of high efficiency. At the same time, the lye treatment after cooking is not sufficient, resulting in the discharge of waste liquid causing great environmental pollution. Therefore, it is urgent to design a method for producing refined cotton with high efficiency, environmental protection and energy saving to solve the above problems. Summary of the invention

[0004] The purpose of the present invention is to provide a method for producing refined cotton with high efficiency, environmental protection and energy saving, so as to solve the above-mentioned shortcomings in the prior art.

[0005] In order to achieve the above object, the present invention provides the following technical solutions: A method for producing refined cotton with high efficiency, environmental protection and energy saving, comprising the following steps: S1. Select high-quality cotton linters; S2. Prepare cooking liquid: The main components of the cooking liquid include sodium hydroxide and water, and the cooking aids are: ethanol, biological enzymes, hydrogen peroxide, and regulators; The proportion of sodium hydroxide to cotton linters is 30-40%, the proportion of water to cotton linters is 40-50%, the proportion of ethanol to cotton linters is 10-15%, the proportion of biological enzyme to cotton linters is 9-12%, the proportion of hydrogen peroxide to cotton linters is 8-10%, and the proportion of regulator to cotton linters is 3-6%; Steps for using cooking liquid: a. High liquid ratio penetration: Use lye in the ratio of cotton linters to cooking liquid of 1:3-5 to penetrate cotton linters. b. Small liquor ratio cooking: Use the ratio of cotton linter to cooking liquor of 1:1-3 to carry out cotton linter small liquor ratio alkali cooking. c. Hydrogen peroxide bleaching; S3, alkali liquor cooking: cooking in a cooking ball, mixing cotton linters with cooking liquor, and heating the cooking liquor from low to high; S4, bleaching and post-treatment: Using hydrogen peroxide for bleaching after cooking can further remove iron from the pulp, improve the whiteness of the pulp, and reduce the use of sodium hypochlorite.

[0006] In a preferred embodiment of the present invention, in S1, short fibers are still left on the cotton seeds after ginning, and these short fibers are stripped off by a linter to obtain cotton linters; Cotton linters are classified into first-class cotton linters, second-class cotton linters and third-class cotton linters.

[0007] As a preferred solution of the present invention, in S2, after a. high liquid ratio infiltration, b. low liquid ratio cooking and c. hydrogen peroxide bleaching, alkali can be saved by more than 50%, the amount of black liquor can be reduced by 1 / 3, and the COD content of black liquor can be reduced to 6000-8000 mg / L. Due to the effect of hydrogen peroxide, the iron content of pulp can be made less than 10ppm, and the whiteness of cotton pulp can be ≥80% without bleaching.

[0008] As a preferred solution of the present invention, in S2: Pre-soak barrel penetration: Using a pre-soak barrel for lye penetration before cooking helps to improve the penetration of lye into the cotton linters; Twin-screw extrusion impregnation penetration: Using twin-screw extrusion technology for alkali solution penetration can more effectively distribute the alkali solution evenly in the cotton linters; Convection heating technology: The use of convection heating can improve the uniformity of temperature distribution inside the steamer bulb, thereby improving the cooking quality.

[0009] As a preferred solution of the present invention, in S2, the cotton linters are penetrated by the cooking liquid by one of the pre-soak barrel penetration, twin-screw extrusion impregnation penetration and convection heating technologies.

[0010] In a preferred embodiment of the present invention, the biological enzyme is one of cellulase, pectinase, laccase, cellulase and the like.

[0011] As a preferred embodiment of the present invention, at the initial stage of cooking, the temperature in the cooking ball is heated to 80-110 degrees Celsius and kept warm for 10-15 minutes; In the middle of the cooking process, heat the temperature in the cooking ball to 110-120 degrees Celsius and keep it warm for 12-18 minutes; At the end of the cooking process, heat the temperature in the cooking ball to 120-130 degrees Celsius and keep it warm for 12-20 minutes.

[0012] In a preferred embodiment of the present invention, the cooking aid is added to the cooking ball in the middle stage of cooking, and before the initial stage of cooking, the cotton linters are soaked in the prepared alkali solution and water for at least 30 minutes.

[0013] As a preferred scheme of the present invention, post-processing includes removing the cotton linters from the cooking ball, filtering the alkali solution, allowing the filtered alkali solution to enter the interior of the first slurry pool, and adding acid to adjust the pH value at the same time, then filtering the material inside the first slurry pool with a detergent, transporting the liquid to the interior of the second slurry pool, and then adding acid to the liquid inside the second slurry pool and circulating it to the cooking ball, thereby extracting the treated cotton linters from the interiors of the first slurry pool and the second slurry pool, drying and crushing them.

[0014] In a preferred embodiment of the present invention, the acid solution is one of acetic acid, hydrochloric acid, acetic acid, citric acid and boric acid.

[0015] In the above technical scheme, the present invention provides a method for producing refined cotton with high efficiency, environmental protection and energy saving, and the beneficial effects are: Saving more than 50% of alkali: By optimizing the cooking process, using alkali solution with a liquid ratio of 1:4 for initial penetration, and then using a liquid ratio of 1:2 for small liquid ratio alkali cooking, the amount of alkali can be significantly reduced, while reducing the amount of black liquor and COD content.

[0016] Improve production efficiency: adopt the above technical scheme, not only can improve the cooking quality of cotton linters, but also can reduce labor intensity and improve production efficiency.

[0017] Through the application of the above technologies and methods, the cotton linter alkali liquor cooking process has not only been optimized, but also achieved remarkable results in environmental protection and efficiency. These improvements help to improve the overall quality and production efficiency of cotton linter pulping, while reducing production costs and environmental impact. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0019] Figure 1 A structural schematic diagram is provided for an embodiment of a method for producing refined cotton with high efficiency, environmental protection and energy saving according to the present invention.

[0020] Figure 2 A structural schematic diagram is provided for an embodiment of a method for producing refined cotton with high efficiency, environmental protection and energy saving according to the present invention.

[0021] Figure 3 A structural schematic diagram is provided for an embodiment of a method for producing refined cotton with high efficiency, environmental protection and energy saving according to the present invention. DETAILED DESCRIPTION

[0022] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation mode, structure, characteristics and effects of the present invention are described in detail below in combination with the accompanying drawings and preferred embodiments.

[0023] like Figure 1-3 As shown, an embodiment of the present invention provides a method for producing refined cotton with high efficiency, environmental protection and energy saving, comprising the following steps: S1. Select high-quality cotton linters; S2. Prepare cooking liquid: The main components of the cooking liquid include sodium hydroxide and water, and the cooking aids are: ethanol, biological enzymes, hydrogen peroxide, and regulators; The proportion of sodium hydroxide to cotton linters is 30%, the proportion of water to cotton linters is 40%, the proportion of ethanol to cotton linters is 10%, the proportion of biological enzyme to cotton linters is 9%, the proportion of hydrogen peroxide to cotton linters is 8%, and the proportion of regulator to cotton linters is 3%; Steps for using cooking liquid: a. High liquid ratio penetration: Use alkali solution with a ratio of 1:4 between cotton linters and cooking liquid to penetrate cotton linters. b. Small liquor ratio cooking: Use the ratio of cotton linter to cooking liquor of 1:2 to perform cotton linter small liquor ratio alkali cooking. c. Hydrogen peroxide bleaching; S3, alkali liquor cooking: cooking in a cooking ball, mixing cotton linters with cooking liquor, and heating the cooking liquor from low to high; S4, bleaching and post-treatment: Using hydrogen peroxide for bleaching after cooking can further remove iron from the pulp, improve the whiteness of the pulp, and reduce the use of sodium hypochlorite.

[0024] In this embodiment, the following steps are included: S1. Select high-quality cotton linters. After cotton is ginned, the short fibers still remain on the cotton seeds. Then use a linter stripping machine to strip these short fibers to obtain cotton linters; The cotton linters are graded into Class I cotton linters, Class II cotton linters and Class III cotton linters; Type I cotton linters: Generally, it is the first-grade velvet, and the hand-pulled length of the cotton fiber is 13 mm or more (including 13 mm). Class I velvet is based on its appearance. It is mainly used to weave cotton blankets, velvet clothes, etc.

[0025] Type II cotton linters: Generally, it is second-grade velvet. The weight of cotton fibers with a length of 12 mm or more (including 12 mm) accounts for no more than 25% of the total fiber weight; the weight of fibers with a length of 3 mm or less accounts for no more than 60% of the total fiber weight. The grade is determined by three indicators: maturity, sulfuric acid insoluble matter, and ash content. Second-grade velvet is mainly used for smokeless gunpowder, film, high-grade paper, etc.

[0026] Three types of cotton linters: Generally, it is three-way velvet. The weight of cotton fiber with a length of 12 mm or more (including 12 mm) accounts for no more than 5% of the total fiber weight; the weight of fiber with a length of 3 mm or less accounts for no more than 80% of the total fiber weight. The grade is determined by three indicators: maturity, sulfuric acid insoluble matter, and ash content. Three-way velvet is mainly used to make high-grade paper of chemical fiber.

[0027] S2. Prepare cooking liquid: The main components of the cooking liquid include sodium hydroxide and water, and the cooking aids are: ethanol, biological enzymes, hydrogen peroxide, and regulators; The proportion of sodium hydroxide to cotton linters is 30%, the proportion of water to cotton linters is 40%, the proportion of ethanol to cotton linters is 10%, the proportion of biological enzyme to cotton linters is 9%, the proportion of hydrogen peroxide to cotton linters is 8%, and the proportion of regulator to cotton linters is 3%; The enzyme composition is one of cellulase, pectinase, laccase, cellulase, etc., and can effectively remove the fluff on cotton seeds by soaking cotton. Compared with the traditional chemical delinting and mechanical delinting processes, the enzyme composition has the characteristics of high efficiency and environmental protection, and can reduce the seed breakage rate and increase the seed germination rate, and can replace the existing chemical and mechanical delinting processes.

[0028] The cooking aid is added to the cooking ball in the middle of cooking. Before the initial stage of cooking, the cotton linters are soaked in the prepared alkali solution and water for at least 30 minutes. Steps for using cooking liquid: a. High liquid ratio penetration: Use alkali solution with a ratio of 1:4 between cotton linters and cooking liquid to penetrate cotton linters. b. Small liquor ratio cooking: Use the ratio of cotton linter to cooking liquor of 1:2 to perform cotton linter small liquor ratio alkali cooking. c. Hydrogen peroxide bleaching Pre-soak barrel penetration: Using a pre-soak barrel for lye penetration before cooking helps to improve the penetration of lye into the cotton linters; Twin-screw extrusion impregnation penetration: Using twin-screw extrusion technology for alkali solution penetration can more effectively distribute the alkali solution evenly in the cotton linters; Convection heating technology: The use of convection heating can improve the uniformity of temperature distribution inside the steamer bulb, thereby improving the cooking quality.

[0029] The cotton linters can be penetrated by cooking liquid by selecting one of the following technologies: pre-soak barrel penetration, twin-screw extrusion impregnation penetration, or convection heating.

[0030] After a. high liquid ratio permeation, b. low liquid ratio cooking and c. hydrogen peroxide bleaching, alkali can be saved by more than 50%, the amount of black liquor can be reduced by 1 / 3, and the COD content of black liquor can be reduced to 6000~8000mg / L. Due to the effect of hydrogen peroxide, the iron content of pulp can be reduced to <10ppm, and the whiteness of cotton pulp can be ≥80% without bleaching. S3, alkali liquor cooking: cooking in a cooking ball, mixing cotton linters with cooking liquor, and heating the cooking liquor from low to high; At the beginning of the cooking process, heat the temperature in the cooking ball to 100 degrees Celsius and keep it warm for 12 minutes; When the cooking temperature reaches 100°C, these substances begin to react with alkali and additives to generate amino acids and dissolve. Protein accounts for about 0.88% of the cooked fiber, and wax and fat are mainly distributed in the primary wall of cotton linters, with complex composition, including fatty acids, fatty esters, and high alcohols. In the early stage of cooking, fatty acids and fatty esters are saponified and dissolved, while high alcohols are assisted to dissolve by the emulsification ability of surfactants.

[0031] In the middle of the cooking process, heat the temperature in the cooking bulb to 108 degrees Celsius and keep it warm for 15 minutes; When the cooking temperature rises to 105-110℃, pectin and tannin react with alkali. Pectin accounts for about 0.88% of the cooked fiber, while tannin mainly comes from cottonseed husk, accounting for 3% of the cottonseed husk.

[0032] At the end of the cooking process, heat the temperature in the cooking ball to 125 degrees Celsius and keep it warm for 15 minutes; When the cooking temperature rises to 120-130°C, the acidic phenols, hydroxyl groups, etc. in the lignin begin to react with the alkali and hydrolyze into alkali cellulose that is easily soluble in alkali solution.

[0033] S4, bleaching and post-treatment: Using hydrogen peroxide for bleaching after cooking can further remove iron from the pulp, improve the whiteness of the pulp, and reduce the use of sodium hypochlorite.

[0034] The post-treatment includes taking the cotton linters out of the cooking ball, filtering the alkali solution, and the filtered alkali solution enters the interior of the first slurry pool, and acid is added to adjust the pH value at the same time, and then the material inside the first slurry pool is treated with a filter detergent, and the liquid is transported to the interior of the second slurry pool, and the liquid inside the second slurry pool is acidified and circulated to the cooking ball, so that the cotton linters after treatment are extracted from the interior of the first slurry pool and the second slurry pool, and then dried and crushed; The acid solution is one of acetic acid, hydrochloric acid, acetic acid, citric acid and boric acid.

[0035] After the above-mentioned multiple post-processing steps, the refined cotton in the alkali solution can be efficiently extracted, and at the same time, the waste liquid treatment effect of the cooking alkali solution is better, so that after it is discharged, it will not cause pollution to the environment, achieving the purpose of energy saving and environmental protection.

[0036] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A method for producing refined cotton with high efficiency, environmental protection and energy saving, characterized in that: The following steps are involved: S1. Select high-quality cotton linters; S2. Prepare cooking liquid: The main components of the cooking liquid include sodium hydroxide and water, and the cooking aids are: ethanol, biological enzymes, hydrogen peroxide, and regulators; The proportion of sodium hydroxide to cotton linters is 30-40%, the proportion of water to cotton linters is 40-50%, the proportion of ethanol to cotton linters is 10-15%, the proportion of biological enzyme to cotton linters is 9-12%, the proportion of hydrogen peroxide to cotton linters is 8-10%, and the proportion of regulator to cotton linters is 3-6%; Steps for using cooking liquid: a. High liquid ratio penetration: Use lye in the ratio of cotton linters to cooking liquid of 1:3-5 to penetrate cotton linters. b. Small liquor ratio cooking: Use the ratio of cotton linter to cooking liquor of 1:1-3 to carry out cotton linter small liquor ratio alkali cooking. c. Hydrogen peroxide bleaching; S3, alkali liquor cooking: cooking in a cooking ball, mixing cotton linters with cooking liquor, and heating the cooking liquor from low to high; S4, bleaching and post-treatment: Using hydrogen peroxide for bleaching after cooking can further remove iron from the pulp, improve the whiteness of the pulp, and reduce the use of sodium hypochlorite.

2. The method for producing refined cotton with high efficiency, environmental protection and energy saving according to claim 1, characterized in that: In S1, the short fibers still remain on the cotton seeds after ginning, and these short fibers are stripped off by a linter to obtain cotton linters; Cotton linters are classified into first-class cotton linters, second-class cotton linters and third-class cotton linters.

3. The method for producing refined cotton with high efficiency, environmental protection and energy saving according to claim 1, characterized in that: In S2, after a. high liquid ratio infiltration, b. low liquid ratio cooking and c. hydrogen peroxide bleaching, alkali can be saved by more than 50%, the amount of black liquor can be reduced by 1 / 3, and the COD content of black liquor can be reduced to 6000~8000mg / L. Due to the effect of hydrogen peroxide, the iron content of pulp can be reduced to <10ppm, and the whiteness of cotton pulp can be ≥80% without bleaching.

4. The method for producing refined cotton with high efficiency, environmental protection and energy saving according to claim 1, characterized in that: In S2: Pre-soak barrel penetration: Using a pre-soak barrel for lye penetration before cooking helps to improve the penetration of lye into the cotton linters; Twin-screw extrusion impregnation penetration: Using twin-screw extrusion technology for alkali solution penetration can more effectively distribute the alkali solution evenly in the cotton linters; Convection heating technology: The use of convection heating can improve the uniformity of temperature distribution inside the steamer bulb, thereby improving the cooking quality.

5. The method for producing refined cotton with high efficiency, environmental protection and energy saving according to claim 4, characterized in that: In S2, the cotton linters are penetrated by the cooking liquid by selecting one of the pre-soak barrel penetration, twin-screw extrusion impregnation penetration, and convection heating technologies.

6. The method for producing refined cotton with high efficiency, environmental protection and energy saving according to claim 1, characterized in that: The biological enzyme may be one of cellulase, pectinase, laccase, cellulase and the like.

7. The method for producing refined cotton with high efficiency, environmental protection and energy saving according to claim 1, characterized in that: At the beginning of the cooking process, heat the temperature in the cooking ball to 80-110 degrees Celsius and keep it warm for 10-15 minutes; In the middle of the cooking process, heat the temperature in the cooking ball to 110-120 degrees Celsius and keep it warm for 12-18 minutes; At the end of the cooking process, heat the temperature in the cooking ball to 120-130 degrees Celsius and keep it warm for 12-20 minutes.

8. The method for producing refined cotton with high efficiency, environmental protection and energy saving according to claim 7, characterized in that: The cooking aid is added to the cooking ball in the middle stage of cooking. Before the initial stage of cooking, the cotton linters are soaked in the prepared alkali solution and water for at least 30 minutes.

9. The method for producing refined cotton with high efficiency, environmental protection and energy saving according to claim 1, characterized in that: Post-processing includes taking out the cotton linters from the cooking ball, filtering the alkali solution, allowing the filtered alkali solution to enter the interior of the first slurry pool, and adding acid to adjust the pH value at the same time, then filtering the material inside the first slurry pool with a detergent, transporting the liquid to the interior of the second slurry pool, and then adding acid to the liquid inside the second slurry pool and circulating it to the cooking ball, so that the cotton linters after treatment are extracted from the interior of the first slurry pool and the second slurry pool, and then dried and crushed.

10. The method for producing refined cotton with high efficiency, environmental protection and energy saving according to claim 9, characterized in that: The acid solution is one of acetic acid, hydrochloric acid, acetic acid, citric acid and boric acid.

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