Online measurement of air permeability of the hott

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Measurement of paper permeability

key words: permeability; Measurement; The derivative system of calibrating 6 particle flocculation system -- three-stage composil system on the basis of micro particle flocculation system, the newly developed three-stage composil system is a typical representative that can give full play to the retention effect when the wet end chemistry of paper machine becomes more complex. The retention mechanism of the system is basically the same as that of the particle system, except that special cationic polymers are applied according to the characteristics of heteroanions in the paper to eliminate their influence and provide conditions for the particle system to play a role in the future. Therefore, the system can be regarded as a derivative system or an extension system of the particle flocculation system, which can also be called a multivariable (ternary) retention system. The features of the new system are briefly introduced below. 6.1 the influence of proportioning mechanical pulp, waste paper deinked pulp (DIP) and coating damaged pulp in paper on production operation 6.1.1 the influence of wood resin in mechanical pulp contains wood resin in micro mechanical pulp, which ranges from 0.3 to 0.8 μ M is composed of small particles, which are strongly anionic. Therefore, the paper material system needs a lot of cationic charge balance to play the role of chemicals in the paper material. In addition, the resin will condense in the production process and pollute papermaking and woolen cloth, causing resin obstacles such as paper breaking. 6.1.2 influence of organic acid salt in mechanical pulp the soluble substances in micro ground wood pulp are mainly composed of organic acid salt, which increases the conductivity in the system and reduces the adsorption capacity of cationic starch. 6.1.3 the influence of deinked pulp and coating damaged pulp. The residual calcium and other salt electrolytes in the micro deinked pulp, and the calcium sulfate generated by the reaction of aluminum sulfate in the paper and calcium carbonate in the coating damaged paper will lead to the increase of the conductivity of the paper. The salt content in the paper is high, especially the divalent salt such as Ca2 +, which has a strong shielding effect on the negative charge on the filler, fine fibers and fiber surface, thus greatly reducing the adsorption and reaction activity of CPAM and Cs on these paper components. The latex adhesive in micro coated paper can form 0.2 ~ 1.0 μ M small particle "white resin", its hazard is the same as that of wood resin. The following three-stage compoz replacement is simple and convenient; The IL system adds special cationic polymers to the pulp to eliminate the adverse effects of the above impurities and ensure the efficient operation of production. 6.2 three stage composil system 6.2.1 "first stage" -- use redifloc to fix the resin figure

figure 10redifloc to reduce the effect of resin (GP)

apply special low molecular weight cationic polymer redifloc to the pulp. Redifloc is an anion trapping system, which can reduce the adverse effects of dissolved and dispersed impurities in the pulp, and can fix wood resin or white resin on the pulp fiber, Make it unable to agglomerate to produce resin barrier. Fig. 10 shows the effect of rediflocr-1 and rediflocr-2 on reducing resin. It can be seen from the figure that the effect of redifloc is better than that of polyaluminum chloride. 6.2.2 "second stage" - adding high molecular weight polymers. As mentioned above, the pulp contains more mechanical pulp and waste water. When deinking paper pulp, the conductivity of the pulp is high, which reduces the adsorption performance of anionic polymers such as starch or even has a negative adsorption effect. Therefore, a new type of high Yang ionized starch (HCS) was developed. HCS has a high charge density, which is 2 ~ 4 times higher than the cationic degree (%n) of the previous cationic starch, so it can absorb more fibers than the previous cationic starch even under the condition of high conductivity. Thus, when added to the pulp, it can play a greater role in helping to retain under adverse manufacturing conditions, and can also enhance the paper. 6.2.3 "third stage" - add colloidal silica to complete the flocculation of the composil system. On the basis of the role of redifloc and HCs, add colloidal silica to the paper material to complete the three-stage operation of the composil system. Finally, according to the above action mechanism, a good micro flocculation will be produced, and ideal retention and paper uniformity effects will be achieved. 6.2.4 production application examples: the micro clip former has a papermaking speed of 1030m/min, and uses paper materials containing ground wood pulp and coated pulp to produce micro coated paper. The conductivity of white water is 1500 μ S/cm, cation demand 25 μ Eq/l, pH 7.2; The paper machine retention aid uses PAM 0.025% (250PPM), which is added after the paper machine screen, and PAC 0.34%, which is added before the flushing pump. After investigating the wet end condition of the paper machine, the experimental machine was regularly checked and revised, and the following composil system was introduced: ① in micro ① add resin fixative redifloc41500.07% (700ppm) to the mixing pulp pool in front of the paper machine; Add cpam0.02% (200ppm) in front of the paper machine screen in the micro ②; In micro ③, PAC was added before the flushing pump, and its amount decreased from 0.34% to 0.2%; Add 0.021% (210ppm) colloidal silica after the paper machine screen in micro ④. In micro scale, a single retention aid PAM was added, and the three-stage composil system was used to achieve the following results: ① in micro scale, the ash retention rate of paper increased by 10 ~ 15 percentage points; In the micro ② multi disc filter, the solids are reduced by 12%; The pinholes in the micro ③ paper sheet are reduced by 41%; In micro ④, the opacity is improved because the ash content in the paper increases by 2%; In micro ⑤, the output increased by 8%. Based on the above reasons, the coating performance has also been improved. 7 Integra retention system Integra system uses coagulant, coagulant and micro flocculent drugs alone or in combination, and has achieved retention, drainage and good paper that comprehensively meet the needs of the paper making system

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