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Editorial: Foam forming: Technology of many opportunities, TAPPI JOURNAL August 2019
ABSTRACT: Over the past ten years, the forest sector has faced big changes due to the decreased demand of printing papers and the fast growth in packaging and tissue products. Weekly news on the marine waste problem and global warming have raised public awareness and stimulated increased interest in bio-based materials, chemicals, and fuels.
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Upscaling of foam forming technology for pilot scale, TAPPI JOURNAL August 2019
ABSTRACT: The need for production cost savings and changes in the global paper and board industry during recent years have been constants. Changes in the global paper and board industry during past years have increased the need for more cost-efficient processes and production technologies. It is known that in paper and board production, foam typically leads to problems in the process rather than improvements in production efficiency. Foam forming technology, where foam is used as a carrier phase and a flowing medium, exploits the properties of dispersive foam. In this study, the possibility of applying foam forming technology to paper applications was investigated using a pilot scale paper forming environment modified for foam forming from conventional water forming. According to the results, the shape of jet-to-wire ratios was the same in both forming methods, but in the case of foam forming, the achieved scale of jet-to-wire ratio and MD/CD-ratio were wider and not behaving sensitively to shear changes in the forming section as a water forming process would. This kind of behavior would be beneficial when upscaling foam technology to the production scale. The dryness results after the forming section indicated the improvement in dewatering, especially when foam density was at the lowest level (i.e., air content was at the highest level). In addition, the dryness results after the pressing section indicated a faster increase in the dryness level as a function of foam density, with all density levels compared to the corresponding water formed sheets. According to the study, the bonding level of water- and foam-laid structures were at the same level when the highest wet pressing value was applied. The results of the study show that the strength loss often associated with foam forming can be compensat-ed for successfully through wet pressing.
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Measurement of the dynamics of fluid sorption for tissue papers, TAPPI Journal July 2019
ABSTRACT: Liquid absorption ability belongs to the most important features of tissue papers. Due to non-homo-geneous internal and superficial structures, precise and fast evaluation of this property is challenging. The main aim of the presented research was to design an experimental device dedicated to the measurement of the kinetics of wetting phenomenon for tissue papers. The second aim was to evaluate whether it was possible to use image analysis for more precise characterization of liquid absorption properties of tissue paper. The obtained results showed that the method used, based on image analysis supported by gravimetric methods, proved to efficiently and quantitatively characterize the dynamics of liquid absorption for tissue papers. Supplementary parameters such as absorption anisotropy and in-plane velocity were obtained. Different experi-mental results were obtained for various tissue paper grades. Furthermore, water absorption capacity calculated from image analysis data correlated with results obtained according to the standard method EN ISO 12625-8:2010 “Tissue paper and tissue products—Part 8: Water-absorption time and water-absorption capacity, basket-immersion test method.” Hence, the presented device quantitatively characterizes and discriminates water absorption phenom-enon for tissue papers.
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Citrus-based hydrocolloids: A water retention aid and rheology modifier for paper coatings, TAPPI Journal July 2019
ABSTRACT: The rheological and dewatering behavior of an aqueous pigmented coating system not only affects the machine runnability but also affects the product quality. The current study describes the use of natural hydrocol-loids derived from citrus peel fibers as a rheology modifier in paper coating applications. The results were compared with carboxymethyl cellulose (CMC) in a typical paper coating system. Water retention of the coating formulation was increased by 56% with citrus peel fibers compared to a default coating, and it also was higher than a CMC-containing coating. The Brookfield viscosity of paper coatings was found to increase with citrus peel fibers. Compared to CMC, different citrus peel fibers containing coating recipes were able to achieve similar or higher water retention values, with no change or a slight increase in viscosity. Coatings were applied on linerboard using the Mayer rod-coating method, and all basic properties of paper were measured to assess the impact of citrus peel fiber on the functional value of the coatings. Paper properties were improved with coated paper containing citrus peel fibers, including brightness, porosity, smoothness, surface bonding strength, and ink absorption.
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Editorial: TAPPI Journal reinstates the “Technical Brief” short-form research paper, TAPPI Journal June 2019
ABSTRACT: For many years, TAPPI Journal (TJ) accepted submissions of “Technical Briefs” (also known as Technical Notes or Brief Notes) in addition to the full-length papers peer-reviewed papers that you have typically seen in more recent years. The TJ Editorial Board is once again accepting these short-form papers, as readers may have noticed in the last issue with publication of Tom Lindstrom’s short nanocellulose re-view (TAPPI Journal 18[5]: 308[2019]). Another Technical Brief appears on p. 391 of the current issue.
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The evolution of reel statistical methods, TAPPI Journal June 2019
ABSTRACT: Multiple statistical methods for calculating the variance partition analysis (VPA) of reel data have existed for decades. In the paper industry, VPA is also commonly known as reel statistics. VPA commonly consists of total variance (TOT) that is then divided into three components: cross direction (CD), machine direction (MD), and residual (RES). A common mathematical procedure is referred to as ANOVA (analysis of variance). TAPPI Standard Test Method T 545 “Cross-machine grammage profile measurement (gravimetric method)” addresses paper testing and includes the ANOVA equations that have also been used to analyze scanning data.In the 1990s, TAPPI published TIP 1101-01 “Calculation and partitioning of variance using paper machine scanning sensor measurements,” which contained simple formulas that were easy to implement and could be used by a nov-ice to generate statistics on a spreadsheet. All involved quality control system (QCS) suppliers agreed to support this common method in their QCS. TIP 1101 was recently revised, and this paper concerns the analysis of data collected from a scanning sensor in a QCS and the creation of a common method for the calculation of reel statistics by TAPPI’s Process Control Division.
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Editorial: Nanocellulose: What's next?
Many of the researchers in this field in the late 1990s and early 2000s were challenged in terms of translation research issues due to the limited production capacity of nanocellulosics on a global stage. To address this call, several pilot-plant production plants have been developed and can now deliver NC on multikilo/ton scale as these issues are gradually being resolved.
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Research needs for nanocellulose commercialization and applications
INTRODUCTION: This short review deals with some applications and research needs for nanocellulosic (NC) materials; primarily cellulose nanocrystals (CNC), cellulose nanofibers (CNF), and bacterial cellulose (BC). Whereas CNC and BC materials are fairly homogenous, CNF materials represent a wide sector of different materials, often with a high heterogeneity. This is due to different pretreatment methods (mechanical, chemical, enzymatic), woodbased or agricultural-based materials, delignification and bleaching procedures, etc. The purpose of this comprehensive review is not to discuss the various production methods, for which the reader may consult with a selected number of reviews [1-6]; thus, the focus is on practical applications. Practical applications and potential markets were also discussed some years ago by other investigators [7-8]. Upscaling and choice of pretreatment methods, as well as economic considerations and different business models, have also been discussed, along with: œ Toxicity and environmental issues [9-10] œ The complex characterization of cellulose nanomaterials [4] The reader should also be aware of new contenders to the three classic groups of cellulosic nanomaterials, which are already in a commercial phase. These include cellulose filaments [11-12] and materials from mechanical grinding processes [13], and these materials may be nanostructures or not, depending on our classification. Finally, as indicated by the editorial on p. 275, scientists are currently taking a deep dive into the fundamental features of nanocellulosic materials [14-15].
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Sources, collection, and handling of noncondensible gases in modern kraft pulp mills
ABSTRACT: This work describes and discusses sources of noncondensible gases (NCG) in modern kraft pulp mills and modern NCG collection from process units where odor emissions can occur if these gases are released to the surroundings. A mill-wide overview of NCG sources and collection in modern pulp mills is provided. Using modern practices, malodorous gases can be collected to the extent that a pulp mill is essentially odor free. The key to limiting complaint-causing odors is prevention of these emissions during process disturbances, equipment malfunctions, operator errors, and other unforeseen occurrences.
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Prehydrolysis kraft pulping of jute cutting and caddis mixture for rayon production
ABSTRACT: Jute cutting, jute caddis, and cutting-caddis mixtures were prehydrolyzed by varying time and temperature to get about 90% prehydrolyzed yield. At the conditions of 170°C for 60 min of prehydrolysis, the yield for 100% jute cutting was 76.3%, while the same for jute caddis was only 67.9%. But with prehydrolysis at 150°C for 60 min, the yield was 90% for jute cutting, where 49.94% of original pentosan was dissolved and prehydrolysis of jute caddis at 140°C in 60 min yielded 86.4% solid residue. Jute cutting-caddis mixed prehydrolysis was done at 140°C for 30 min and yielded 92% solid residue for 50:50 cutting-caddis mixtures, where pentosan dissolution was only 29%. Prehydrolyzed jute cutting, jute caddis, and cutting-caddis mixtures were subsequently kraft cooked. Pulp yield was only 40.9% for 100% jute cutting prehydrolyzed at 170°C for 60 min, which was 10.9% lower than the prehydrolysis at 140°C. For jute cutting-caddis mixed prehydrolysis at 140°C for 45 min followed by kraft cooking, pulp yield decreased by 3.3% from the 100% cutting to 50% caddis in the mixture, but 75% caddis in the mixture decreased pulp yield by 6.7%. The kappa number 50:50 cutting-caddis mixture was only 11.3. Pulp bleachability improved with increasing jute cutting proportion in the cutting-caddis mixture pulp.