阅读说明：本技术 一种造纸湿部高效助留助滤体系的添加工艺 (Addition process of efficient retention and drainage system for papermaking wet part ) 是由 张成飞 张益安 谢昌武 颜利兵 李苗 于 2020-06-03 设计创作，主要内容包括：本发明提供一种造纸湿部高效助留助滤体系的添加工艺,采用中等阳电荷中等分子量的助留助滤剂和膨润土组成的二元助留助滤体系,包括：将中等阳电荷中等分子量的助留助滤剂溶解于水中,搅拌25-32min,得到助留助滤剂溶液；在造纸湿部的纸浆中加入PAC,以对纸浆进行预处理,将预处理后的纸浆送至二次冲浆泵中进行冲浆处理,得到第一纸浆；将膨润土加入第一纸浆中,再将第一纸浆送至网前筛,得到筛选后的第二纸浆；将助留助滤剂溶液采用Trumpjet混合装置加入第二纸浆中,再将第二纸浆送至流浆箱中,即得混合纸浆。该添加工艺能提高混合纸浆的助留助滤效果,并减少高效助留助滤剂的添加量,降低造纸生产成本。(The invention provides an adding process of a papermaking wet part efficient retention and drainage system, which adopts a binary retention and drainage system consisting of retention and drainage agent with medium positive charge and medium molecular weight and bentonite, and comprises the following steps: dissolving retention and filtration aid with medium positive charge and medium molecular weight in water, and stirring for 25-32min to obtain retention and filtration aid solution; adding PAC (polyaluminium chloride) into paper pulp at a papermaking wet end to pretreat the paper pulp, and conveying the pretreated paper pulp to a secondary pulp pump for pulp washing treatment to obtain first paper pulp; adding bentonite into the first paper pulp, and then conveying the first paper pulp to a screen in front of a screen to obtain screened second paper pulp; and adding the retention and drainage aid solution into the second paper pulp by adopting a Trumpjet mixing device, and sending the second paper pulp into a head box to obtain the mixed paper pulp. The addition process can improve the retention and drainage effects of the mixed paper pulp, reduce the addition of the high-efficiency retention and drainage aid and reduce the production cost of papermaking.)

1. An adding process of a papermaking wet part efficient retention and drainage system is characterized in that a binary retention and drainage system consisting of retention and drainage agent with medium positive charge and medium molecular weight and bentonite is adopted, and the adding process comprises the following steps:

step 1: dissolving 0.15-0.25Kg/T of retention and filtration aid with medium positive charge and medium molecular weight in water, and stirring for 25-32min to obtain retention and filtration aid solution;

step 2: adding 1.0-2.0Kg/T PAC of paper into paper pulp at a papermaking wet end to pretreat the paper pulp, and sending the pretreated paper pulp to a secondary pulp pump for pulp washing treatment to obtain first paper pulp;

and step 3: adding 2.0-3.0Kg/T of bentonite into the first paper pulp, and then sending the first paper pulp to a screen in front of a net to obtain screened second paper pulp;

and 4, step 4: and diluting the retention and drainage aid solution by adopting a Trumpjet mixing device, adding the diluted retention and drainage aid solution into second paper pulp, and sending the second paper pulp into a head box to obtain mixed paper pulp.

2. The addition process of the papermaking wet end high efficiency retention and drainage system according to claim 1, characterized in that in the step 1, the stirring time is 30 min; the concentration of the retention and drainage aid solution is 0.25%.

3. The addition process of the papermaking wet end high-efficiency retention and drainage system according to claim 1, characterized in that the degree of cationicity of the retention and drainage agent is 20-25%.

4. The addition process of the papermaking wet end high-efficiency retention and drainage system according to claim 1, characterized in that the molecular weight of the retention and drainage aid is 500-800 ten thousand.

5. The addition process of the papermaking wet end high efficiency retention and drainage aid system according to claim 1, characterized in that the retention and drainage aid is acrylamide-ethylene diamine tetraacetic acid copolymer obtained by copolymerizing 86-92 parts by weight of acrylamide monomer and 9-12 parts by weight of ethylene diamine tetraacetic acid.

6. The addition process of the papermaking wet end high efficiency retention and drainage system according to claim 5, characterized in that in the retention and drainage aid, 90 parts by weight of acrylamide monomer and 10 parts by weight of ethylene diamine tetraacetic acid are used.

7. The addition process of the papermaking wet-end high-efficiency retention and drainage system according to claim 1, characterized in that in the step 4, the retention and drainage aid is diluted to a concentration of 0.05-0.1% by using a Trumpjet mixing device.

Technical Field

The invention relates to the technical field of papermaking, in particular to an adding process of a papermaking wet part efficient retention and drainage system.

Background

Currently, in the papermaking industry, retention and drainage aids for the wet end of papermaking are divided into unit retention and drainage systems, binary retention and drainage systems and ternary retention and drainage systems. The effect of the ternary retention and drainage system is superior to that of the binary retention and drainage system, and the binary retention and drainage system is superior to that of the unit retention and drainage system. Wherein, the unit retention and filter aid system is polyacrylamide (PAM for short), which is a retention and filter aid with high molecular and low positive charges, the binary retention and filter aid system is PAM + inorganic/organic microparticles, and the ternary retention and filter aid system is PAM + inorganic/organic microparticles + bentonite.

At present, the cost of the existing ternary retention and drainage system is too high, which affects the cost of papermaking production, while the existing binary retention and drainage system and the existing unit retention and drainage system cannot meet the expected retention and drainage effects of paper pulp, which causes the loss of paper ash (such as fine filler) in the paper pulp, thus leading to the improvement of papermaking production cost, and the addition of the binary retention and drainage system and the unit retention and drainage system is large, and the drainage speed is slow, thus prolonging the papermaking production period.

Disclosure of Invention

The invention aims to provide an adding process of a high-efficiency retention and drainage system of a papermaking wet part, aiming at the defects of the prior art, and the adding process can improve the retention and drainage effects of mixed paper pulp, reduce the adding amount of high-efficiency retention and drainage aids and reduce the papermaking production cost.

The invention discloses an adding process of a papermaking wet part efficient retention and drainage system, which adopts a binary retention and drainage system consisting of retention and drainage agent with medium positive charge and medium molecular weight and bentonite, and comprises the following steps:

step 1: dissolving 0.15-0.25Kg/T of retention and filtration aid with medium positive charge and medium molecular weight in water, and stirring for 25-32min to obtain retention and filtration aid solution;

step 2: adding 1.0-2.0Kg/T PAC (polyaluminium chloride) of paper into paper pulp at a papermaking wet end to pretreat the paper pulp, and sending the pretreated paper pulp to a secondary fan pump for fan treatment to obtain first paper pulp;

and step 3: adding 2.0-3.0Kg/T of bentonite into the first paper pulp, and then sending the first paper pulp to a screen in front of a net to obtain screened second paper pulp;

and 4, step 4: and diluting the retention and drainage aid solution by adopting a Trumpjet mixing device, adding the diluted retention and drainage aid solution into second paper pulp, and sending the second paper pulp into a head box to obtain mixed paper pulp so as to improve the retention and drainage aid effect of the mixed paper pulp in the subsequent papermaking production process.

Preferably, in the step 1, the stirring time is 30 min; the concentration of the retention and drainage aid solution is 0.25%.

Preferably, the cationic degree of the retention and drainage aid is 20-25%.

Preferably, the molecular weight of the retention and drainage aid is 500-800 ten thousand.

Preferably, the retention and drainage aid is an acrylamide-ethylene diamine tetraacetic acid copolymer obtained by copolymerizing 86-92 parts by weight of acrylamide monomer and 9-12 parts by weight of ethylene diamine tetraacetic acid, the acrylamide-ethylene diamine tetraacetic acid copolymer is a retention and drainage aid with medium positive charge and medium molecular weight, and the retention and drainage aid is obtained by adding ethylene diamine tetraacetic acid into acrylamide and copolymerizing, so that the retention and drainage aid is stable in structure, has a function of improving the retention rate of mixed slurry and has an effect of improving the drainage of the mixed slurry on a net.

Further preferably, in the retention and drainage aid, the acrylamide monomer is 90 parts by weight, and the ethylene diamine tetraacetic acid is 10 parts by weight. In this case, the acrylamide-ethylenediaminetetraacetic acid copolymer obtained

Preferably, in the step 4, the retention and drainage aid is diluted to the concentration of 0.05-0.1% by using a Trumpjet mixing device.

Compared with the prior art, the invention has the following beneficial effects:

the adding process comprises the following steps: firstly, 0.15-0.25Kg/T of paper of retention and drainage aid with medium positive charge and medium molecular weight is dissolved in water to prepare retention and drainage aid solution; adding 1.0-2.0Kg/T PAC of paper to the paper pulp for pretreatment, and sending the pretreated paper pulp to a secondary pulp pump for pulp washing treatment to obtain first paper pulp; adding 2.0-3.0Kg/T of bentonite into the first paper pulp, and then sending the first paper pulp to a screen in front of a net to obtain screened second paper pulp; and diluting the retention and drainage aid solution by adopting a Trumpjet mixing device, adding the diluted retention and drainage aid solution into second paper pulp, and sending the second paper pulp into a head box to obtain mixed paper pulp so as to improve the retention and drainage aid effect of the mixed paper pulp in the subsequent papermaking production process.

In order to reduce the comprehensive cost of papermaking and improve the profit margin of paper production, a binary retention and drainage aid system is adopted, and in order to improve the retention and drainage effect of paper pulp, the retention and drainage aid agent with medium positive charge and medium molecular weight replaces the traditional high-molecular PAM with low positive charge so as to improve the drainage effect of the high-molecular PAM with low positive charge, and then bentonite is combined so as to improve the retention effect of the PAM, thereby forming the binary retention and drainage aid system with high-efficiency retention and drainage effect; and before the paper pulp enters the secondary fan pump, PAC is added to pretreat the paper pulp so as to neutralize the anionic garbage in the paper pulp and supplement cations, and meanwhile, the PAC is added to quickly stabilize the charge degree (PCD for short) and the conductivity of the cations in the paper pulp, so that the retention and drainage effects of the paper pulp are prevented from being influenced by the unstable factors of the PCD and the conductivity, and the retention and drainage effects of the paper pulp are further improved. Furthermore, in order to promote the mixing of the retention and drainage aid with medium positive charge and medium molecular weight in the second paper pulp, the retention and drainage aid with medium positive charge and medium molecular weight is dissolved in water to prepare a retention and drainage aid solution; and the retention and drainage aid solution is diluted at a high speed by adopting a Trumpjet mixing device and then added into the second paper pulp, so that the mixing and dispersion of the retention and drainage aid solution in the second paper pulp are further promoted.

Therefore, by adopting the binary retention and drainage system and combining the addition process disclosed by the invention, the high-efficiency retention and drainage effects on the mixed paper pulp can be achieved (particularly, the retention rate of the paper pulp adopting the traditional binary retention and drainage system is only about 75%, while the retention rate of the mixed paper pulp adopting the binary retention and drainage system disclosed by the invention can be increased to 80-85%, and the dryness of the net part of the mixed paper pulp is increased by 1-2%), the addition amount of the binary retention and drainage system can be reduced (particularly, the addition amount of the retention and drainage aid with medium positive charge and medium molecular weight is only 1/2-1/3 of the addition amount of PAC in the traditional binary retention and drainage system), and the papermaking production cost is reduced (compared with the traditional binary retention and drainage system, the retention and drainage aid cost per ton paper net part of the mixed paper pulp is reduced by 7.35-11.27 yuan).

Drawings

Fig. 1 is a block diagram schematically illustrating the structure of an addition process of the high-efficiency retention and drainage system of the wet end of papermaking of the present invention.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.