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Volume 50, Issue 5
Displaying 1-11 of 11 articles from this issue
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Pulping and BleachingMotoo Matsukura1996 Volume 50 Issue 5 Pages 757-771
Published: May 01, 1996
Released on J-STAGE: November 16, 2009
JOURNAL FREE ACCESSResearch and Development should seek for the increase of productivity because pulp and paper industry depend on the big capital investment. Therefore R & D for pulping and bleaching is also seeking for the effective productivity with conservation of resources and environmental protection.
There are two issues in Kraft pulp as a main material, a low yield in pulping and environmental problems by bleaching effluent. It may be important to plant the specie which gives higher yield for a increasing of pulp yield. Then it is the most important topic to create the new specie by modifying lignin structures, and to improve plantation technology. On bleaching technology there is a trend to minimize the total organochlorine compounds in a mill effluent. And many researches are conducting to develop non-chlorine bleaching. Recently a new large plant for organosolve pulping was started to prove the feasibility. It will be expected to start the operation in future.
There are several issues in mechanical pulp as another main material, namely 1) utilization of low grade resources, 2) energy saving, 3) light and heat induced yellowing, 4) pitch troubles, 5) environmental load of the effluent. It would be necessary to improve opacity to increase the use of radiata pine as a new resource. Biomechanical pulping method was developed for energy saving. But the method can not be applied into the process because of cost and a low brightness. Finally application of biotechnology into papermaking process for pitch troubles was conducted successfully.View full abstractDownload PDF (2179K) -
Hideki Shibazaki, Shigenori Kuga1996 Volume 50 Issue 5 Pages 772-776
Published: May 01, 1996
Released on J-STAGE: November 16, 2009
JOURNAL FREE ACCESSBacterial cellulose, which consists of extremely fine microfibrils of pure cellulose, has been attracting keen interests as a novel functional material. Possible utilization of this material in papermaking and other fields are reviewed, including 12 patents cited.View full abstractDownload PDF (4780K) -
Chuichi Honma1996 Volume 50 Issue 5 Pages 777-781
Published: May 01, 1996
Released on J-STAGE: November 16, 2009
JOURNAL FREE ACCESSDCS means distributed (from risks ets) control system.
As PCs (personal computers) proliferate in the mill, there has been a definite trend toward open architecture in pulp and paper making process automation.
PCs must now be lower priced and higher performance to suit mill automation needs.
This paper discribes the user friendly functions of the new era DCS, called right sizing system (right means all right).
A lots of the new era DSC, named Right Sizing Systems are expected to be introduced in the pulp and paper making processes.View full abstractDownload PDF (574K) -
Koji Otsubo1996 Volume 50 Issue 5 Pages 782-786
Published: May 01, 1996
Released on J-STAGE: November 16, 2009
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Jan Wåle, Sven Lahti, Göran Sund1996 Volume 50 Issue 5 Pages 787-791
Published: May 01, 1996
Released on J-STAGE: April 23, 2010
JOURNAL FREE ACCESSPressure vessels and piping in the pulp and paper industry are subject to inspections with intervals of one year or more. The damage observed during inspections is evaluated and recorded, which makes comparisons over the years possible. During recent years a rapid corrosion damage development of various process components has been noticed. The reasons for this accelerating corrosion rate and typical equipment attacked are discussed in the paper.
One important factor is the rapid development of new and refined processes to achieve higher quality products. Existing equipment is sometimes under service conditions deviating considerably from design data. Another important factor is the strong tendency to closing up the systems for minimizing wastage to the sourroundings caused by increased environmentals demands. Closing up the systems affects the compostions of process chemicals and causes accumulation of detrimental species. Specific media parameters involved are e. g. temperature, pH, electrode potential and flow velocity. The increasing corrosion attack requires improved corrosion resistant materials, thus, frequent application of several new steel grades is another factor to consider.
Accelerated corrosion rate and damage extent has been observed for various equipment, such as batch and continuous digesters, black liquor evaporators, piping and storage vessels for process-chemicals, bleaching process vessels etc. Examples of typical components, type of damage and material/media combinations suffering from corrosion attack are discussed in the paper.View full abstractDownload PDF (1029K) -
Wood Science Committee1996 Volume 50 Issue 5 Pages 792-799
Published: May 01, 1996
Released on J-STAGE: November 16, 2009
JOURNAL FREE ACCESS -
[in Japanese]1996 Volume 50 Issue 5 Pages 800
Published: May 01, 1996
Released on J-STAGE: November 16, 2009
JOURNAL FREE ACCESSDownload PDF (357K) -
Yasuo Kojima1996 Volume 50 Issue 5 Pages 801-810
Published: May 01, 1996
Released on J-STAGE: November 16, 2009
JOURNAL FREE ACCESSIt was found in preliminary work on this study that Larch wood produce thermo-mechanical pulps with lower strength properties compared with those of from other soft woods such as Spruce and Fir. Therefore, various pretreatment or combination of the pretreatment with post-treatment had been applied to produce the acceptable pulp from Larch wood in high yield. The former is called as chemi-thermo-mechanical pulping (CTMP) and the latter is called modified chemi-thermo-mechanical pulping (modified CTMP).
To obtain the CTMP from Larch wood, wood chips were subjected to various sulfite liquors, neutral sulfite, bisulfite and alkaline sulfite, and then defibrated in a laboratory Asplund defibrator (type D). The resultant pulps were beaten in a PFI mill to given CSF value, and physical properties were determined on handsheets prepared from the pulps.
Bisulfite treatment gave the CTMP with superior properties to these of from other treatments. Neutral sulfite treatment also resulted in the CTMP with high strength properties, but not as good as those of the CTMP from bisulfite treated wood chips. The strength properties of CTMP prepared from alkaline sulfite treated chips were only marginally better than those of the TMP.
As far as strength properties are concerned, however, the properties of Larch CTMP produced from suitable pretreated chips were only comparable with those of TMP from spruce wood. To improve the properties of CTMP from Larch wood, ozone treatment was applied as a post-treatment. Ozonized CTMP were prepared from CTMP by subjecting the pulp to single or two-stage ozone treatment in gaseous phase. The results showed that ozone treatment improved the strength properties of CTMP used in this study. Two-stage ozone treatment gave the pulps with higher breaking length and lower tear factor compared with those of from single stage ozone treatment. Extraction of ozoneized CTMP with 1% sodium hydroxide resulted in the pulp with higher breaking length and lower tear factor in lower yield compared with those of pulps produced by 1% sodium bisulfite extraction. Additional advantages arising from the use of ozone included its ability to act as a bleaching agent.View full abstractDownload PDF (2920K) -
Screening of fungi having ability for depression of light-induced color reversion of mechanical pulps with reductive indicatorsKazutaka Itoh, Yoshie Kawamura, Hiroshi Syutou, Tae Oki, Sanrou Tachib ...1996 Volume 50 Issue 5 Pages 811-819
Published: May 01, 1996
Released on J-STAGE: November 16, 2009
JOURNAL FREE ACCESSScreening of fungi having ability for depression of light-induced color reversion of mechanical pulps was carried out by using 2, 6-dichloroindophenol sodium salt and methoxy-p-quinone as reductive indicators. First, we tried the screening of fungi having ability for reduction of 2, 6-dichloroindophenol sodium salt on Czapek-Dox's agar plate medium from soils and 94 fungi were found by the screening. In the second step, each 94 fungi was incubated in Czapek-Dox's liquid medium containing methoxy-p-quinone and 26 fungi having ability of decoloration of the quinone were obtained. In the third step, reactivity between extracellular crude enzymes prepared from each 26 fungi and methoxy-p-quinone was measured and screened fungi having the higher reactivity. By using this method, a fungus named 1, 701 having higher ability for depression of the color reversion was obtained. The fungus could be depressed 56% of the color reversion of thermomechanical pulpsView full abstractDownload PDF (2631K) -
1996 Volume 50 Issue 5 Pages 820-824
Published: May 01, 1996
Released on J-STAGE: November 16, 2009
JOURNAL FREE ACCESSDownload PDF (6105K) -
[in Japanese], [in Japanese]1996 Volume 50 Issue 5 Pages 825-829
Published: May 01, 1996
Released on J-STAGE: November 16, 2009
JOURNAL FREE ACCESSDownload PDF (684K)
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