Photochemical paper pulp bleaching method and device

A photochemical and photochemical reaction technology, applied in the field of pulp and paper, can solve the problems of bleaching wastewater that cannot be closed and circulated, requires high corrosion resistance, and large pollution, and achieves low anti-corrosion performance requirements, high physical strength, and delignification high degree of effect

Inactive Publication Date: 2007-09-19
GUANGXI UNIV
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Problems solved by technology

[0006] Aiming at the deficiencies of the above-mentioned traditional bleaching technology and process, combined with the current situation of my country's paper industry, in order to overcome the shortcomings of the existing pulp bleaching technology, such as large pollution, high corrosion resistance requirements, and the inability to close the cycle of bleaching wastewater, the inventors researched and proposed A process and equipment for photochemical bleaching of pulp. This technology not only does not use chlorine-containing bleaching agent at all, is very friendly to the environment, but also can remove the residual lignin in pulp to more than 95% under normal pressure conditions. The brightness is bleached to more than 85% (ISO), so as to obtain bleached pulp with good physical strength

Method used

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  • Photochemical paper pulp bleaching method and device
  • Photochemical paper pulp bleaching method and device
  • Photochemical paper pulp bleaching method and device

Examples

Experimental program
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Effect test

Embodiment 1

[0037] Embodiment 1, after paper pulp is dispersed, add water to make the suspension of 0.5-5% concentration, through the 0.05-1% EDTA solution pretreatment of 15-60 minute by absolute dry paper pulp weight content, join in a photochemical bleaching reactor Main equipment, adjust the pH value of the reaction system with sodium hydroxide solution to 8-12, add catalyst rose bengal, hydrogen peroxide, and titanium dioxide, the concentration is 0.05-1% of the absolute dry pulp weight content, and place it in the photochemical bleaching The 500W sodium lamp light source in the main equipment is irradiated, and the photochemical bleaching reaction occurs through the catalytic action of the catalyst. The reaction temperature is 30°C, and the bleaching reaction time is 8 hours. After the reaction, the residual lignin in the pulp is removed to obtain the required whiteness. , and then get bleached standby pulp after washing.

Embodiment 2

[0038] Embodiment 2, after paper pulp is dispersed, add water to make the suspension of 2% concentration, through the 0.05-1% DTPA solution pretreatment of 15-60 minute by absolute dry paper pulp weight content, join the main equipment of a photochemical bleaching reactor , adjust the pH value of the reaction system with lye to be 8-12, add the catalyst phlox red (PH), sulfoaluminum, zinc phthalocyanine and sodium silicate whose concentration is 0.5% of dry pulp weight content, 0.3% Titanium dioxide is irradiated by a 1500W mercury lamp light source placed in the main equipment of photochemical bleaching, and through the catalytic action of the catalyst, a photochemical bleaching reaction occurs. The reaction temperature is 80°C, and the bleaching reaction time is 3 hours. lignin to obtain the desired brightness, and then washed to obtain bleached standby pulp.

Embodiment 3

[0039] Example 3, after the pulp is dispersed, add water to make a suspension with a concentration of 1%, after 15-60 minutes of soaking pretreatment, add it to the main equipment of a photochemical bleaching reactor, and adjust the pH value of the reaction system with calcium hydroxide 8-12, add catalyst eosin (EO), and hydrogen peroxide, titanium dioxide, the concentration is 0.05-1% of absolute dry pulp weight content, through the 800W sodium lamp light source that is placed in the main equipment of photochemical bleaching, through catalyst The photochemical bleaching reaction occurs, the reaction temperature is 20°C, and the bleaching reaction time is 10 hours. After the reaction, the residual lignin in the pulp is removed to obtain the required brightness, and then the bleached pulp is obtained after washing.

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Abstract

Based on photochemical principle, plant fiber pulp after being pre-treated is irradiated with light, and in alkali environment and under the aid of introduced oxygen or air and photobleaching catalyst, the residual lignin in pulp is degraded via photochemical reaction into leached out fragments and thus eliminated, resulting in high whiteness pulp. During the bleaching process, different shielding agent may be added to shield partial light selectively to protect the physical strength of pulp. The bleaching process is environment friendly, and has less corrosion to the apparatus and simple operation.

Description

technical field [0001] The invention relates to pulping and papermaking technology, in particular to a method and equipment for delignification and bleaching of plant fiber pulp. Background technique [0002] After the plant fiber raw material is pulped, the color of the pulp varies from off-white to dark brown depending on the raw material and the pulping method. The color of pulp mainly comes from the lignin in the pulp. In order to expand the use of pulp and improve the whiteness of pulp, it must be bleached to remove the colored substances in the pulp and give the pulp the required physical and chemical properties. In traditional pulp bleaching, chlorine-containing bleaching agents, such as chlorine gas, hypochlorite, chlorine dioxide, etc., play a very important role. Due to the high bleaching efficiency of chlorine-containing bleaching agents, the damage to fibers is relatively low, making it Get a wide range of applications. [0003] According to research data, trad...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): D21C9/10
Inventor 王双飞宋海农杨崎峰黄显南许开绍宾飞农尚勇朱红祥
Owner GUANGXI UNIV
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