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Preparation method of industrial hemp full stalk bleaching chemical pulp

A technology for industrial hemp and chemical pulp, applied in pulp bleaching, pulping with inorganic alkali, non-woody plant/crop pulp, etc., can solve the problems of waste of resources, large differences in pulp quality, complicated processes, etc., to reduce the environment pressure, reduce wastewater discharge, and improve the effect of the ecological environment

Active Publication Date: 2012-08-22
YUNNAN JUHENG TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

To make hemp pulp from hemp husks, it is necessary to peel the hemp first, but the existing hemp peeling machines have disadvantages such as low peeling efficiency and high impurity content in the hemp peeled, which is not suitable for large-scale production
In addition, since the hemp stalk core is about four times that of the hemp husk in the whole hemp stalk, if the hemp stalk core is not utilized, it will cause a great waste of resources
In order to reduce the waste of hemp raw materials, some manufacturers try to peel off the hemp husk and hemp stalk core first, and then use different processes for pulping. Not only is the hemp peeling cumbersome and the quality of the peeling is not high, but also different processes are required for pulping , the process is complicated, more equipment is invested, and the quality of the prepared slurry is also quite different.
Due to the large difference in the organizational structure of hemp husk and hemp stalk core, no one has solved the technical problem of directly pulping hemp whole stalks, so this has always been a blank spot in this technical field

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] A method for preparing industrial hemp whole stalk bleached chemical pulp, the method is as follows:

[0023] (1) Use a drum chipper to cut the whole hemp stalk into pieces with a length of about 2 cm. After coarse screening, use the sulfate method to cook and make pulp. The cooking conditions are: the amount of sodium hydroxide, that is, the amount of alkali used is the absolute 18% of dry raw material weight (as Na 2 O meter), the degree of vulcanization is 18% (in Na 2 O meter), the liquid ratio during cooking is 1:4, and the heating curve is: heating time 110min, holding time 165min, maximum temperature 170°C; after cooking, the slurry yield is 50.8%, kappa value is 11.8, and residual alkali is 14g / L;

[0024] (2) The slurry prepared in step (1) is washed, beaten, and sieved in sequence, and then chlorinated after being dehydrated by a rotary screen thickener. Lignin treatment, the pulp concentration during treatment is 2.5%, and the amount of chlorine used is 53k...

Embodiment 2

[0031] A method for preparing industrial hemp whole stalk bleached chemical pulp, the method is as follows:

[0032] (1) Use a drum chipper to cut the whole hemp stalk into pieces with a length of 1-3cm. After coarse screening, use the kraft method to cook and make pulp. The cooking conditions are: the amount of sodium hydroxide is the amount of alkali used for hemp 17% of the dry raw material weight (as Na 2 O meter), the degree of vulcanization is 18% (in Na 2 O meter), the liquid ratio during cooking is 1:4, and the heating curve is: heating time 110min, holding time 175min, maximum temperature 160°C; after cooking, the slurry yield is 51.4%, the Kappa value is 11.4, and the residual alkali is 18g / L;

[0033] (2) The slurry prepared in step (1) is washed, beaten, and sieved in sequence, and then chlorinated after being dehydrated by a rotary screen thickener. Lignin treatment, the pulp concentration during treatment is 3.0%, and the amount of chlorine used is 48kg of dry pu...

Embodiment 3

[0040] A method for preparing industrial hemp whole stalk bleached chemical pulp, the method is as follows:

[0041] (1) Cut the whole hemp stalk into 3cm-long sections with a drum chipper, and after coarse screening, use the kraft method to cook and make pulp. The sodium hydroxide used for cooking is represented by its Na 2 The O content is calculated as 22% of the absolute dry raw material weight of the hemp stalk; 2 In terms of O content, the vulcanization degree is 19% of the weight of the absolute dry raw material of hemp stalks, the liquid ratio during cooking is 1:3, and the heating curve is: heating time 90min, holding time 180min, maximum temperature 155°C; pulp yield after cooking 49.7%, kappa value 9.3, residual alkali 21g / L;

[0042] (2) The slurry prepared in step (1) is washed, beaten, and sieved in sequence, and then chlorinated after being dehydrated by a rotary screen thickener. Lignin treatment, the pulp concentration during treatment is 3.5%, and the amoun...

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Abstract

The invention provides a preparation method of industrial hemp full stalk bleaching chemical pulp, comprising the following steps of: cutting hemp stalk into small sections, pulping by a sulfate cooking method, sequentially washing, beating, screening pulp, dehydrating and chloridizing, carting out hydrogen peroxide-enhanced alkali treatment on chloridized pulp, carrying out medium / thick pypocholoride bleaching on the alkali-treated pulp by pypocholoride bleaching liquor, and carrying out medium / thick hydrogen peroxide complementary bleaching on the obtained bleaching pulp by hydrogen peroxide bleaching liquor, to finally obtain the hemp full stalk pulp bleaching chemical pulp. The invention provides a method for preparing the bleaching chemical pulp by directly using the industrial hemp full stalk, so that t the pulp is directly prepared from the hemp full stalk, the foundation for realizing the large-scale development of the preparation of the industrial hemp pulp can be laid, and the improvement of the ecological environment can be further importantly pushed and promoted.

Description

technical field [0001] The invention relates to the technical field of pulp preparation for papermaking, in particular to a method for producing bleached chemical pulp by using the whole stalk of industrial hemp as a raw material. Background technique [0002] Hemp is a plant suitable for extensive cultivation in my country. During the whole growth process of hemp, pesticides and herbicides are rarely used, and its fiber output per unit area per unit time is much higher than that of wood. The bast fiber of hemp is excellent Hemp paper produced from hemp is a green and environmentally friendly high-grade paper, which can be widely used in cigarette paper, tea bag paper, tobacco flakes, filter paper, banknotes, bond paper and various high-end packaging materials. [0003] The existing technology of adopting hemp raw material to produce paper pulp mainly utilizes hemp husk to make hemp husk pulp, as Chinese patent CN 1204317C, discloses a kind of preparation method of industrial...

Claims

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Application Information

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IPC IPC(8): D21C3/02D21C9/10D21C9/16D21H11/12
Inventor 孙川关庆芳杨杰
Owner YUNNAN JUHENG TECH
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