Thermo-mechanical pulp

Blattellaquinone, 27 259 Bleach activator, ethyleneamines application, 8 500t, 504-505 Bleach boosting, 70 304-305 Bleached board products, 78 130 Bleached chemo-thermo mechanical pulp (BCTMP), 74 57 Bleached montan wax, 9 677 Bleaches. See also Bleaching... 

I Akamatsu, K Yoshihara, H Kamishima, T Fujii. Influence of white-rot fungi on poplar chips and thermo-mechanical pulping of fungi-treated chips. J Jpn Wood Res Soc 30 697-702, 1984. 

Mechanical pulping aqueous environments are similar to paper machine white waters. In chemi-thermo mechanical pulping, however, the addition of sulfur ions can increase corrosivity. Pressurized presteaming of wood chips from seaborne logs can result in environments conducive to chloride SCC and also to the evolution of wood acids that can cause corrosion in the vapor phase. Wear is a more significant problem than corrosion in mechanical pulping environments. 

The deinking plant is located in Quebec. It uses 80 % old news paper and 20 % old magazines furnish to produce deinked pulp. The plant is located next to a thermo mechanical pulp newsprint mill to which part of the deinked pulp is sent to produce 30 % recycled content paper. The recycling facility was built in the early nineties, and was subsequently modernized at the end of the decade in order to increase its production capacity. During the upgrade, several modifications were made to the pulp treatment sequences and the process water circulation layout. It is estimated that the fresh water intake has been reduced from approximately 21 to IS tons per ton of oven dried pulp produced. Figure 1 shows a simplified layout of the present day plant. 

Processing of Thermo-Mechanical Pulping Data to Enhance PCA and PLS... 

Seasonal variations, changes in incoming chip quality and other external factors that can affect pulp quality are often beyond the control of the thermo-mechanical pulp (TMP) mill operator. Many internal factors are controllable, however, and could possibly be used to counteract these external forces. The ultimate goal is to model in real time parameters that cannot be measured continuously, in order to apply inferential control C soft sensor ) as reported in Strand et al. (2001) and elsewhere (Kooi, 1994 Kresta et al., 1994). Before proposing any such control strategy, however, it is necessary to understand the correlations and trends which are inherent to the refining operation at the heart of the pulp mill, using historical data. 

Figure 4. Dry tensile strength increase (N) of sheets prepared with 80/20 TMP/SWK and different dosages of cationic oxidized guar (0,25 - 1%) of various degrees of oxidation (0-45%) compared to a base sheet prepared without guar addition. Horizontal lines show the strength increase of sheets prepared with different ratio s of Thermo-mechanical Pulp (TMP) and Softwood Kraft Pulp (SWK) compared to the base sheet prepared with 80/20 TMP/SWK.

Richardson D E, Bloom H 1982 Analysis of resin acids in untreated and biologically treated thermo-mechanical pulp effluent. Appita 35 477-482... 

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