Influence of intermittent shredding and continuous

2022-08-21
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Production investigation on the impact of intermittent shredding and continuous drum shredding of waste paper on the quality of shredded pulp

Chen Jia, Chen Jiaxiang, Professor, doctoral supervisor, member of the International Expert Committee on plant resource chemistry of UNESCO. This film is taken by rakta paper mill, which is always at the forefront of the market when the author lectured in Egypt

Abstract: This paper introduces the production investigation of intermittent shredding and continuous drum shredding in several waste paper deinking workshops in Canada and the northern United States. The investigation focused on the influence of season, deinking agent type and pulping time on the quality of pulped pulp. The results showed that the batch pulping with double deinking agent and 30 ~ 60s pulping time had the best pulping quality and minimized the summer effect. The surfactant used in continuous drum pulping seems to be better than the double deinking agent, which is manifested in the low concentration of ink particles and residual ink particles in the pulped pulp. However, because the shredding time (20min) cannot be changed, the long-term shredding will cause the low whiteness of the pulped pulp

key words: intermittent disintegration; Continuous drum disintegration; Summer effect; Deinking agent; Andy postlethwaite, senior vice president of BASF properties materials Asia Pacific, also said: "Innovative materials can inspire and realize various excellent designs and functional shredding times; whether waste paper can be deinked successfully depends on the shredding of waste paper. In the past 25 years, most deinking systems in North America have adopted intermittent shredders; in the recent 5-6 years, some new deinking systems have adopted rotary drum continuous shredders [1] 。 As there are more and more impurities in waste paper, the rotary drum continuous shredder has the trend to replace the intermittent shredder [2]

no, in order to understand the impact of batch and drum continuous shredders on deinking efficiency, Jim merza et al. [2] focused on the seasonality, type of deinking agent and shredding time, conducted production surveys on four batch and two drum continuous shredders in North America, and measured the ink particle concentration (ERIC), ink dust point (ink density) and whiteness of shredded pulp, The relevant investigation and analysis results are introduced as follows for reference

1 advantages and disadvantages of intermittent crusher and drum continuous crusher (see Table 1)

Table 1 advantages and disadvantages of intermittent crusher and drum continuous crusher

advantages

disadvantages

intermittent crusher

(1) it can increase the friction between fibers, except that there are specific requirements for the control mode

(2) the crushing time can change as needed

(3) it can control the degree of ink fragmentation

(2)4) The equipment covers a small area

(5) it can be disintegrated with high slurry concentration or low slurry concentration

(1) high energy consumption

(2) heavy removal Limited degree of large waste

(3) there are certain defects in impurity removal

there are some differences (4) high maintenance costs

rotary drum continuous shredder

(1) energy consumption can be saved by 50%

(2) impurities can be easily removed

(3) disintegration effect is moderate

(4) high slurry concentration disintegration

(5) continuous operation

(6) weight removal with its own belt Large waste device

(1) long disintegration time

(2) ink re adhesion or re deposition increases

(3) high equipment cost

(4) large site is required

intermittent. It can be seen from table 1 that intermittent disintegration and drum continuous disintegration have their own advantages and disadvantages

2 the ratio of shredded raw materials and determination

2.1 waste paper

can not afford onp70% ~ 85%, omg15% ~ 30%

2.2 chemical drugs

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