Method for recovering free starch in papermaking white water

A technology of papermaking white water and cationic starch, which is applied in the field of pulping and papermaking, can solve the problems of paper defects, broken ends, affecting operation efficiency, etc.

Active Publication Date: 2021-02-19
RISINGSTAR BIOTECH GUANGZHOU
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] However, there are some deficiencies in the above-mentioned technologies: in order to prevent the shortening of the starch chain, it is necessary to fully and effectively control the microorganisms and prevent them from secreting amylase. These methods need to add a large amount of Bactericides will affect the subsequent biological treatment of wastewater
In addition, because the starch in papermaking white water mainly comes from surface sizing, its starch molecular weight is low, it is uncharged, and it is difficult to retain it in the paper, resulting in a large amount of starch remaining in the pulping and papermaking system. These starches not only serve as Microbial nutrients will increase microbial growth, and starch accumulation will eventually cause "starch sticky" deposition problems, resulting in paper defects and end breaks, affecting operational efficiency
[0008] So far, there is no real effective solution to the recycling of starch dissolved in papermaking white water

Method used

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  • Method for recovering free starch in papermaking white water
  • Method for recovering free starch in papermaking white water
  • Method for recovering free starch in papermaking white water

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0321] Example 1 Effect of cationic starch binder cetylpyridine hydrochloride (number C7) on starch dissolution and fiber surface adsorption after reacting with starch

[0322] Experimental steps: (1) take cornstarch sample and prepare 7% "standard starch solution"; (2) take an appropriate amount of standard starch solution and add deionized water to dilute to the required concentration of starch solution; (3) take the prepared concentration Put 500mL of starch solution in a beaker, and put it into a 45°C constant temperature water bath, and equilibrate to the specified temperature; (4) Add C7 according to the required concentration, and react for 60 minutes to obtain a modified starch solution; (5) Sampling and centrifuging ( 4000x g) for 5 minutes, take the supernatant to test the starch concentration; (6) add bleached chemical pulp (BKP) to the remaining modified starch solution according to a solid concentration of 1%, and keep stirring for 10 minutes; (7) after the reactio...

Embodiment 2

[0329] The impact of embodiment 2 reaction time on starch binding reaction

[0330] Experimental steps of starch reaction: (1) take corn starch sample and prepare 7% "standard starch solution"; (2) take appropriate amount of standard starch solution and dilute it with deionized water to a starch concentration of about 1800mg / L (or other required concentration) (3) Take 500mL of the prepared starch solution or OCC white water, place it in a beaker, and put it into a 45°C constant temperature water bath, and equilibrate to the specified temperature; (4) Add 30mg / L starch binder as required, When the reaction reaches 1, 3, 5, 10, 30, 60, 90, 120, 300, 600 and 1200 minutes, the sample is centrifuged (4000x g) for 5 minutes, and the supernatant is taken to test the starch content and COD concentration;

[0331] The test procedure of starch adsorption reaction time: steps (1)-(4) are the same as above, (5) when the starch reaction reaches 60 minutes, add 3% chemical pulp (BKP) accor...

Embodiment 3

[0337] Embodiment 3 Reaction temperature is to the influence of starch binding reaction and the adsorption effect of modified starch

[0338] Experimental steps: (1) Take corn starch samples to prepare 7% "standard starch solution"; (2) Take an appropriate amount of standard starch solution and add deionized water to dilute to a starch concentration of about 600mg / L; (3) Take the prepared starch solution 500mL, placed in a beaker, and put into a constant temperature water bath with the required test temperature preset, and equilibrated to the specified temperature; (4) According to the requirements of the test, add 30mg / L cationic starch binder C7 and react for 60 minutes to obtain Modified starch solution; (5) sample centrifugation (4000x g) for 5 minutes, get the supernatant to test starch content and COD concentration; (6) add chemical pulp (BKP ) (Note: The amount of starch binder is equivalent to 1000g / T dry pulp), keep stirring; (7) React for 10 minutes, take the slurry ...

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Abstract

The invention relates to a method for recovering free starch in papermaking white water, comprising the step of reacting a cationic starch complexing agent with the free starch in papermaking white water to modify the free starch; the cationic starch complexing agent The chemical structure consists of the following parts: i) one or more hydrophobic groups, wherein at least one hydrophobic group can react with starch to form an inclusion complex, and ii) one or more hydrophilic groups, at least one of which is hydrophilic The water group is a cationic hydrophilic group; the hydrophobic group and the hydrophilic group are respectively located at two ends of the same molecular structure and connected by chemical bonds to form an asymmetric and polar structure. The method can effectively reduce the content of free starch in papermaking white water, thereby reducing the COD discharge of papermaking wastewater.

Description

technical field [0001] The invention relates to the technical field of pulping and papermaking technology, in particular to a method for recovering free starch in papermaking white water. Background technique [0002] The entire production process of the pulp and paper industry, including from material preparation to paper making, chemical recycling, and paper processing, requires a large amount of water for conveying, washing, dispersing materials, and cooling equipment. Although there are recycling, treatment, and reuse in the production process, a large amount of waste water is still discharged into the water body, causing serious pollution to the water environment. Worldwide, paper industry wastewater is an important source of pollution. For example, Japan and the United States list paper industry wastewater as one of the six major public hazards and one of the five major public hazards. [0003] At present, my country's paper industry wastewater discharge and COD disch...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): D21C11/00C08B31/00C08B31/18C08B31/04C08B31/12
CPCC08B31/00C08B31/04C08B31/125C08B31/185D21C11/0078
Inventor 王祥槐张福山李志军胡维维
Owner RISINGSTAR BIOTECH GUANGZHOU
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