Straw cutting-free method for preparing straw pulp by spherical digester alkali digestion

A technology of alkaline cooking and grass cutting, which is applied in the field of papermaking to achieve the effects of increasing the concentration of black liquor, improving the environment, and increasing the degree of lignin

Inactive Publication Date: 2012-04-04
KUNMING UNIV OF SCI & TECH TECH IND SALES MANAGEMENT
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

It's just that compared with wood pulping, the status quo that is obviously at a disadvantage has not been substantially changed

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030] (1) Wash the straw with water; put it into a trapezoidal groove with a water depth of 80-100cm, bring the straw in the water to the belt through the rising belt conveyor, and arrange 3 rows of horizontal water spray pipes in the front and back above the straw out of the water surface Spray it, and the sprayed straw is sent to the steaming ball through the belt conveyor, and the straw is scattered and distributed to every corner of the ball by the fast-rotating grass distributor with a rotating shaft extending vertically into the steaming ball and above. Until the material is loaded to the pot mouth, remove the forage distributor, insert a stainless steel straight pipe with an inner diameter of about 18mm and an oblique angle of about 45o from the pot mouth to the bottom of the steaming ball, and connect the plastic pipe to the water pump on the top of the straight pipe. Squeeze out the excess water at the bottom of the steaming ball, and then take out the straight tube; ...

Embodiment 2

[0037] (1) Wash the straw with water;

[0038] (2) Add hot alkali solution NaOH with a mass concentration of 20g / L to the grass raw material washed with water in step (1) and put into steamed balls, wherein the amount of hot alkali solution added is the amount of alkali used in conventional caustic soda anthraquinone cooking 75%, then add water according to the solid-liquid mass ratio of 1:6, mix well, heat up for 90min until the temperature of the mixture is 110°C, and then keep it warm for 100min; then use the conventional caustic soda anthraquinone method for cooking, the amount of alkali 15% of the total mass of the grass raw materials, and the amount of anthraquinone is 0.1% of the total mass of the grass raw materials; wherein, the water after washing the grass raw materials is clarified, and the obtained sludge is used for returning to the field; the obtained clear water is returned to washing and recycling;

[0039] (3) When step (2) is cooked until the lignin detached f...

Embodiment 3

[0044] (1) washing the wheat straw;

[0045] (2) Add hot alkali solution NaOH and NaOH and Na 2 S, the amount of hot alkali solution added is 75% of the amount of alkali used in conventional kraft cooking, and then water is added according to the solid-liquid mass ratio of 1:6, after mixing evenly, heat up for 70 minutes until the temperature of the mixture is 150°C , and then keep warm for 40min; then use the conventional sulfate method to cook, the amount of alkali used is 14% of the total mass of the grass raw materials, and the degree of sulfidation is 20%; wherein, the water after washing the grass raw materials is clarified, and the obtained sludge is used as a backwash Field use; the obtained clean water is returned to washing and recycling;

[0046] (3) When step (2) is cooked until the lignin detached from the grass raw materials reaches 90%, the cooking is suspended, and the black liquor I is discharged to obtain grass pulp; the black liquor I is filtered, and the f...

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PUM

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Abstract

The invention provides a straw cutting-free method for preparing straw pulp by spherical digester alkali digestion. The method comprises the following steps of: washing a straw raw material; adding a hot alkali solution, adding water, mixing uniformly, and heating; performing digestion by adopting a conventional sulfate method or a caustic soda anthraquinone method; stopping the digestion when the lignin discharged from the straw raw material by the digestion reaches 75 to 90 percent, discharging a black liquor I, and thus obtaining straw pulp; and adding the hot alkali solution into the straw pulp, performing digestion and conventional washing and thus obtaining unbleached pulp, wherein the thin black liquor discharged during washing is a black liquor II, the black liquor II and water are added into the new straw raw material together, and the unbleached pulp is continuously obtained by repeating. The straw cutting process is eliminated in the method, so that the flow for preparing the pulp by using the straw is simplified; and on the premise of ensuring the digestion effect, the concentration of the solid matter of the black liquor can be improved to over 13 percent, the stock loss of the raw material is reduced by about 5 percent, the single-pot digestion capacity is improved by 10 to 15 percent, and the yield and the viscosity of the formed pulp are raised with different degrees.

Description

[0001] technical field [0002] The invention relates to a method for preparing straw pulp, in particular to a method for preparing straw pulp by direct steaming and boiling without cutting the grass, and belongs to the technical field of papermaking. Background technique [0003] Rice straw and wheat straw, as crop residues, have an annual output of hundreds of millions of tons in my country. They are a huge treasure house of papermaking resources, and once became the main plant fiber raw materials relied on by my country's papermaking industry. However, due to the inherent shortage of rice and wheat straw raw materials, it is difficult to compete with the wood pulping process, and the grass pulping industry is gradually shrinking with the development of my country's paper industry. At the same time, limited wood resources are difficult to form an important support for the raw materials of my country's paper industry, making my country's paper industry more and more depende...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): D21C3/02D21C3/22D21H11/12
Inventor 陈克利师睿朱维
Owner KUNMING UNIV OF SCI & TECH TECH IND SALES MANAGEMENT
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