A kind of preparation method of bleached straw pulp

A technology of straw pulp and grass, which is applied in the field of preparation of bleached straw pulp for papermaking, can solve the problems of clean production being inferior to wood raw materials, restricting the development of grass pulping industry, and the low rate of straw pulp acquisition, so as to improve clean production Efficiency, increased comprehensive physical strength of bleached pulp, and significant effects on pulp quality

Inactive Publication Date: 2016-02-10
KUNMING UNIV OF SCI & TECH +1
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  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In the past 10 years, with the higher and higher requirements for environmental pollution control, the inherent deficiencies of grass raw materials have resulted in their clean production level being significantly lower than that of wood raw materials. In addition, the low efficiency of the pulping process has also caused people to be concerned about the pulping of grass raw materials. The problem is quite difficult
Therefore, problems such as low yield, high consumption, and high pollution in the grass pulping process seriously limit the development of the grass pulping industry
[0003] With the development of social economy, people's consumption demand for paper products is constantly increasing and higher requirements are put forward for the quality of paper products. In the past, relatively simple and extensive grass pulping with high yield, especially mechanical pulping, was used. Due to the low quality of straw pulp, the paper products that can be produced are also greatly limited
In order to improve the quality and added value of straw pulp, the chemical pulping method is adopted, but the acquisition rate of straw pulp is not high

Method used

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  • A kind of preparation method of bleached straw pulp

Examples

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preparation example Construction

[0025] figure 1 A schematic flow diagram showing the preparation method of the bleached straw pulp of the present invention. Such as figure 1 As shown, first, the grass raw material and the cooking liquid are added to the cooking equipment at a weight ratio of 1:3-1:6 and mixed evenly, and then the cooking equipment is sealed, wherein the cooking liquid contains alkali. Before the grass raw material is transported to the cooking equipment, the grass raw material is cut short, so that the contact between the grass raw material and the cooking liquid is more thorough and the reaction is more comprehensive. The chopped grass raw materials are subjected to dedusting treatment, and then washed with water to remove impurities therein, and then dehydrated after the water washing. After the above treatment, it is avoided that the pulping efficiency is affected by the dust and sundries brought by the grass raw material itself. The grass raw material used in the present invention is ...

Embodiment 1

[0035] The straw is cut short and dusted, then washed to remove debris and then dehydrated. The dehydrated rice straw is sent into the cooking equipment, and at the same time, the cooking liquid preheated to 90° C. is added and mixed evenly with it, and the weight ratio of the straw to the cooking liquid is 1:3.5. The cooking liquid is an aqueous solution of sodium hydroxide and magnesium sulfate, the consumption of sodium hydroxide is 15% of the weight of rice straw, and the consumption of magnesium sulfate is 2% of the weight of rice straw. After the charging is finished, the cooking equipment is sealed, and oxygen is introduced into it to keep the oxygen pressure in the cooking equipment at 0.5 MPa. Heat the cooking equipment, and cook the rice straw at 130° C. for 30 minutes with the cooking liquid. After cooking, pump the black liquor with low temperature and concentration in the system to lower the temperature in the digester below the boiling point, then spray the obta...

Embodiment 2

[0039] Repeat Example 1, and some reaction parameters are adjusted as follows: the weight ratio of straw and cooking liquid is 1:6, and the cooking liquid is an aqueous solution of sodium hydroxide, sodium sulfide and magnesium sulfate, wherein the consumption of sodium hydroxide and sodium sulfide is rice straw 20% of the weight, the magnesium sulfate consumption is 0.1% of the straw weight, the oxygen pressure in the cooking equipment remains 1MPa, the cooking temperature is 90°C, and the cooking time is 240 minutes. After cooking, the slurry is directly sprayed. The bleaching process was carried out at 70°C for 60 minutes, the concentration of fine pulp was 12%, and the amount of chlorine dioxide was 0.5%.

[0040] In the present example, the results of various indicators of the prepared fine pulp are: fine pulp yield 52.3%, Kappa number 6.7, whiteness 62%ISO, viscosity 810mL / g; each of the bleached straw pulp obtained after bleaching The results of the items are: raw mate...

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Abstract

The invention discloses a preparation method of bleached straw pulp, which comprises the following steps: (1) adding a straw raw material and cooking liquor into cooking equipment in a weight ratio of 1:3-1:6, evenly mixing, and closing the cooking equipment, wherein the cooking liquor contains alkali; (2) introducing oxygen into the closed cooking equipment while keeping the oxygen pressure in the cooking equipment at 0.3-1.0 MPa, and cooking the straw raw material in the cooking liquor at 90-130 DEG C for 30-240 minutes; (3) washing and screening the pulp after finishing the cooking process to obtain fine pulp; and (4) bleaching the fine pulp in the step (3) with chlorine dioxide. The chlorine dioxide can bleach the straw pulp to the whiteness of higher than 80% in one bleaching process, thereby reducing two bleaching processes as compared with the CEH bleaching process usually adopted by a common alkaline method; and thus, the operating cost is lowered by 2 / 3, and the pollutant burden in the bleaching process is lowered by more than 60%.

Description

technical field [0001] The invention relates to the field of papermaking, in particular to a method for preparing bleached straw pulp for papermaking. Background technique [0002] The production of pulp from crop straw (especially straw or wheat straw) has dominated my country's pulp and paper industry for about 40 years. In the past 10 years, with the higher and higher requirements for environmental pollution control, the inherent deficiencies of grass raw materials have resulted in their clean production level being significantly lower than that of wood raw materials. In addition, the low efficiency of the pulping process has also caused people to be concerned about the pulping of grass raw materials. The problem is quite tricky. Therefore, problems such as low yield, high consumption, and high pollution in the grass pulping process seriously limit the development of the grass pulping industry. [0003] With the development of social economy, people's consumption demand...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): D21C5/00D21C9/10
Inventor 陈克利董璐佳蓝海蓝洋
Owner KUNMING UNIV OF SCI & TECH
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