A method for preparing dissolving pulp from whole cotton stalks

A technology for dissolving pulp and cotton stalks, which is applied in pulping with inorganic alkali, pulping with organic solvents, pulping with cellulose raw materials, etc., can solve the problems of large amount of reaction reagents, long reaction time, complicated production process, etc., and achieve Reduce the amount of alkali and energy consumption, consume a large amount of reagents, and increase production efficiency

Active Publication Date: 2021-02-19
SOUTH CHINA UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Based on the concept of comprehensive and effective high value-added utilization of fiber raw materials, in the production process of dissolving pulp with cellulose as the main component, fully consider the high-value utilization of hemicellulose and lignin in cellulose raw materials, and at the same time aim at At present, the production process of dissolving pulp is complicated, and the reaction time is long, and the amount of reaction reagents is large. A pulping method of improving kraft cooking with ethanol and alkali pretreated organic solvent is proposed, and the method of organic pickling is used to reduce the ash content. Improve pulp properties

Method used

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  • A method for preparing dissolving pulp from whole cotton stalks
  • A method for preparing dissolving pulp from whole cotton stalks
  • A method for preparing dissolving pulp from whole cotton stalks

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0051] A. Cotton stalk preparation

[0052] Cotton stalks are mechanically crushed to 5mm, washed with water to remove sand, dust and other impurities, dried at 45°C and packed into bags for later use;

[0053] The main chemical components (%) of cotton stalks are shown in Table 1.

[0054] Table 1

[0055]

[0056]

[0057] The material preparation process in the embodiments is all in this way, and will not be repeated in the following embodiments.

[0058] B. Cotton stalk pretreatment

[0059] Add cotton stalks (40g dry, the same below) to the there-necked bottle, add 3% NaOH (based on the quality of the pretreatment solution, the same below), add 12% ethanol (based on the quality of the pretreatment solution, the same below), add water The concentration of the slurry was adjusted to 10 wt%, mechanical stirring was started, the reaction temperature in the water bath was 50° C., and the reaction time was 80 min.

[0060] After filtering, the pretreatment liquid (fil...

Embodiment 2

[0074] A. Cotton stalk preparation

[0075] With the preparation method in embodiment 1.

[0076] B. Cotton stalk pretreatment

[0077] Add a certain amount of cotton stalks to the three-necked bottle, add 1wt% NaOH, 6wt% absolute ethanol, adjust the solid-liquid ratio (pretreatment reagent to cotton stalk dry mass ratio) to 10:1, and start mechanical stirring. The water bath reaction temperature was 80°C, and the reaction time was 90 minutes.

[0078] Collect the pre-hydrolyzate (filtrate 1) to separate and extract hemicellulose. Add acetic acid to the collected prehydrolyzate to adjust the pH to 6.0-7.0, centrifuge at 4500 rpm for 20 min, and finally filter and separate to obtain hemicellulose.

[0079] The analysis shows that the yield of cotton stalk pulp after prehydrolysis is 76.5% (relative to the absolute dryness of the raw material). According to the relevant standards of TAPPI, the lignin content of the prehydrolyzed cotton stalk pulp is 19.73%, the α-cellulose i...

Embodiment 3

[0092] The cotton stalk dissolving pulp was prepared according to the method and steps disclosed in Example 1, with the difference that absolute ethanol was not added during pretreatment.

[0093] The analysis shows that the yield of cotton stalk pulp after pretreatment is 79.8% (compared to the absolute dryness of the raw material). According to the relevant standards of TAPPI, the lignin content of the pretreated cotton stalk pulp is 20.65%, the α-cellulose content is 67.34%, the pentose polysaccharide content is 5.46%, and the ash content is 3.50%.

[0094] The experimental effects of adding ethanol auxiliary and no ethanol auxiliary during pretreatment are as follows: figure 1 shown.

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Abstract

The invention discloses a method for preparing dissolving pulp from whole cotton stalks. The method comprises the steps of extracting hemicellulose and removing fat and waxy substances through pretreatment with organic alcohol and alkali; removing lignin and pulping through an organic alcohol assisted sulphate cooking method; and carrying out organic acid post-treatment to remove residual ash inorganic salt and the like. The method comprises the following steps: A, pretreating cotton stalks prepared before; B, stewing pretreated cotton stalk pulp by an ethanol-assisted sulfate method; C, carrying out organic acid post-treatment to remove residual ash; D, carrying out chelation treatment and bleaching. The method has the beneficial effects that with the organic alcohol assisted alkali pretreatment, organic alcohol improved sulfate stewing method and organic acid post-treatment process, the reaction conditions are mild, the temperature is low, the time is short and the production efficiency is high; the cotton stalk dissolving pulp has good performance, and the quality requirements of the dissolving pulp for viscose fiber are met; the content of alpha-cellulose is higher than 90%, the content of pentosan is less than 1.39%, and the ash content is less than 0.06%.

Description

technical field [0001] The invention belongs to the field of high-value comprehensive utilization of biomass, and relates to a high-efficiency pulping technology for "stubborn" (high lignin and ash content and difficult to remove) non-wood fiber raw materials, in particular to a method for preparing dissolving pulp from cotton stalks Methods. Background technique [0002] With the increasingly severe forms of energy shortage, environmental pollution and climate change, the comprehensive utilization industry of crop straw has become another new leading industry leading the development of technological innovation and advanced productivity in the contemporary world. [0003] Cotton planting area is large in my country, and cotton stalk resources are very rich. It is a non-wood fiber resource that cannot be ignored. Therefore, it is necessary to study the high value-added utilization of cotton stalks. As far as its chemical composition is concerned, the cellulose content of cot...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): D21C5/00D21B1/02D21C3/02D21C3/20D21C9/02D21H11/12
CPCD21B1/021D21C3/022D21C3/20D21C5/00D21C9/02D21H11/12
Inventor 赵丽红郭淑红何北海
Owner SOUTH CHINA UNIV OF TECH
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