Summaries of February 2006 peer-reviewed papers.TAPPI TAPPI Technical Association of the Pulp and Paper Industry JOURNAL is a monthly publication that includes full-text, peer reviewed research papers exploring every aspect of pulp and papermaking. Each issue presents technically sound, applications-based research; special insights from the authors; and more. TAPPI Membership includes access to all TAPPI JOURNAL content online at www.tappi.org. In addition, convenient print and electronic subscription options are available; TAPPI members receive substantial subscription discounts.
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THREE-DIMENSIONAL OBSERVATION OF COATED PAPER BY CONFOCAL confocal
see confocal microscopy. LASER SCANNING MICROSCOPE
APPLICATION: A confocal laser scanning microscope with the new fluorescence stain technique can show the three-dimensional distribution of a coating binder.
The distribution of coating components and the depth to which coating penetrates into paper are important attributes in determining the final product quality. Many analytical techniques have been proposed to characterize the coating layer, but most are limited in some way or entail difficult procedures for preparing the samples.
A new method uses a confocal laser scanning microscope (CLSM CLSM Confocal Laser Scanning Microscope
CLSM Controlled Low-Strength Material
CLSM Conical Log Spiral Mobile
CLSM Committee of Lunacy and Surreal Madness (band) ) to image the coating layer after it is stained with a fluorescent dye. Rhodamine rhodamine /rho·da·mine/ (ro´dah-men) any of a group of red fluorescent dyes used to label proteins in various immunofluorescence techniques. B is used as the dye because of its fluorescence at the excitation wavelength of 514 nm. Sample preparation is minimal, and no artifacts artifacts
see specimen artifacts. from cross sectioning methods are introduced.
The method was found to be useful in quantifying the depth of coating penetration into the paper. The coating binder was stained with Rhodamine B, but kaolin kaolin (kā`əlĭn): see china clay. , calcium carbonate calcium carbonate, CaCO3, white chemical compound that is the most common nonsiliceous mineral. It occurs in two crystal forms: calcite, which is hexagonal, and aragonite, which is rhombohedral. , and the base paper were stained only slightly or not at all. Because of this selective adsorption, the distribution and position of latex in the coating layer can be characterized.
Bubbles in the coated layer could be imaged by this technique. For a lightweight coated paper, it was found that coating binder penetrated into the base paper. Two coated layers of the double-coated paper could be observed by the difference in contrast. View this paper online at http://www.tappi.org/index.asp?pid=34025&ch=1
Yasushi Ozaki is with Research Institute of National Printing Bureau, 6-4-20 Sakawa, Odawara-city, Kanagawa 256-0816, Japan. Douglas W. Bousfield, and Stephen M. Shaler are with the Paper Surface Science Program, University of Maine "UMO" redirects here, but this abbreviation is also used informally to mean the Mozilla Add-ons website, formerly Mozilla Update
Should not be confused with Université du Maine, in Le Mans, France
The University of Maine , Orono, Maine, 04469-5737. Email Ozaki at email@example.com.
DECREASING CALCIUM OXALATE SCALING BY PARTIAL SUBSTITUTION OF Mg(OH)[.sub.2] FOR NaOH IN THE PEROXIDE BLEACHING OF MECHANICAL PULPS
APPLICATION: By partially replacing NaOH with Mg(OH)[.sub.2], papermakers may be able to decrease oxalate-related scaling without sacrificing brightness in bleached mechanical pulp.
The formation of scale deposits leads to operational problems in a bleach plant. Forms of scaling include calcium oxalate, calcium carbonate, barium sulfate barium sulfate: see barite. , and pitch. The alkaline peroxide process generates oxalate oxalate /ox·a·late/ (ok´sah-lat) any salt of oxalic acid.
A salt or ester of oxalic acid. and oxalate-related scaling in the production lines of bleached mechanical pulps.
Therefore, we wanted to study the potential of partially replacing NaOH with Mg(OH)[.sub.2] as the alkali source during the peroxide bleaching of mechanical pulps. They examined its effect on oxalate formation and brightness and found that the amount of precipitated oxalate was negligible when 30-50% of NaOH was replaced with Mg(OH)[.sub.2] during bleaching. They also found that a higher brightness was achieved than reached with the NaOH-based peroxide process.
Therefore, a partial replacement of NaOH with Mg(OH)[.sub.2] should be a practical solution to oxalate-related scaling in production lines for bleached mechanical pulp. The addition of MgS[O.sub.4] to a peroxide stage can also decrease the amount of precipitated oxalate, but the addition of MgS[O.sub.4] is not as effective as the partial replacement of NaOH with Mg(OH)[.sub.2]. View this paper online at http://www.tappi.org/index.asp?pid=34026&ch=1
Li Yu and Yonghao Ni are with Limerick Pulp and Paper Research and Education Centre, University of New Brunswick The University of New Brunswick (UNB) is a Canadian university located in the province of New Brunswick. The university has two main campuses: the principal campus founded in 1785 in Fredericton and a smaller campus which was opened in Saint John in 1964. , Fredericton, N.B., Canada, E3B 6C2. Email Ni at firstname.lastname@example.org.
MEDIUM CONSISTENCY OXYGEN DELIGNIFICATION PERFORMED WITH A CONTROLLED CAVITATION cavitation
Formation of vapour bubbles within a liquid at low-pressure regions that occur in places where the liquid has been accelerated to high velocities, as in the operation of centrifugal pumps, water turbines, and marine propellers. REACTOR
APPLICATION: This work demonstrates the importance of mass transfer in oxygen delignification and how mills can benefit from working to improve it. This work also showcases an easy oxygen delignification retrofit for mills.
A U.S. mill has conducted a pilot-scale medium consistency oxygen delignification (MCOD MCOD Multicultural Organizational Development Plan (Amnesty International) ) trial using a proprietary reactor as part of an integrated delignification system. Delignification responses were obtained for various operating conditions and multiple chemical charges. Delignification levels of 35% or more were obtained for hardwood pulp. The trials were designed to determine potential operating costs, energy consumption, operational conditions, and benefits associated with a low capital cost installation of this system into an existing washer line. Material and energy balances in conjunction with pilot plant and lab data were used to predict potential net effects of the MCOD system upon operating costs. The effects of the oxygen delignification operation upon pulp physical properties were also determined. View this paper online at http://www.tappi.org/index.asp?pid=34027&ch=1
Peter W. Hart is with MeadWestvaco Corporation, Chillicothe, OH 45601. Douglas Mancosky and Daniel Armstead are with Hydro Dynamics, Inc., Rome, GA 30165. Email Hart at Pwh3@meadwestvaco.com, Mancosky at dmancosky@hydrodynamics hydrodynamics: see mechanics.
The study of fluids in motion. The study is based upon the physical conservation laws of mass, momentum, and energy. .com, or Armstead at email@example.com.
BLACK LIQUOR GASIFICATION gas·i·fy
tr. & intr.v. gas·i·fied, gas·i·fy·ing, gas·i·fies
To convert into or become gas.
A LOW-TEMPERATURE, BLACK LIQUOR GASIFIER MODEL FOR USE IN WinGEMS
APPLICATION: The model can be used in full mill simulations to explore the potential impact of implementing BLG BLG Bulk Liquids and Gases
BLG Borden Ladner Gervais LLP
BLG Boys Like Girls (band)
BLG Bremer Lagerhaus-Gesellschaft AG (Bremen, Germany)
BLG Betalactoglobulin technology.
Black liquor gasification (BLG) is moving closer to commercial realization. Tools to simulate its effects on pulping operations could help mill decision makers in evaluating its implementation. WinGEMS[TM] is a simulation tool that is often used in the pulp and paper industry The global pulp and paper industry is dominated by North American (United States, Canada), northern European (Finland, Sweden) and East Asian countries (such as Japan). Australasia and Latin America also have significant pulp and paper industries. , but it has not had a BLG block.
These researchers developed a BLG model in WinGEMS[TM] to simulate black liquor gasification and determine its effects on mill operations. Several obstacles were overcome in the creation of the block, including the need to support user-defined stream components.
To validate the model, the developers compared the results to process data. The process model generates values for output streams and back-calculates values for input streams. These values were in close agreement with data provided by the manufacturer. The BLG block is currently being used in case studies to determine the effects of varying the rates of carbon conversion. View this paper online at http://www.tappi.org/index.asp?pid=34028&ch=1
Mathias Lindstrom, Ved Naithani, Adrianna Kirkman Kirk´man
n. 1. A clergyman or officer in a kirk.
2. A member of the Church of Scotland, as distinguished from a member of another communion. , and Hasan Jameel are with the Dept. of Wood and Paper Science, North Carolina State University History
CHARACTERIZATION OF CHEMICAL PULP FINES
APPLICATION: This study presents several simple methods for characterizing chemical pulp fines, allowing better control of fines quality.
This study presents a number of new methods for characterizing chemical pulp fines. The methods are used to measure the dewatering Dewatering (dē′wöd·ər·iŋ) is the removal of water from solid material or soil by wet classification, centrifugation, filtration, or similar solid-liquid separation processes. rate, settling rate, and viscosity of a fines suspension, which are closely related to the specific surface area of fines. The dewatering rate of the fines suspension measured with a gravimetric water retention meter that used pressure filtration coincided with the results obtained with a conventional method for measuring the drainage time in a sheet mold. The settling rate measured with a Turbiscan device, which is equipped with an optical head for scanning the sample automatically, correlated with the results of conventional visual observation. The Brookfield viscosity of the fines suspension may be dependent on the degree of hydration hydration /hy·dra·tion/ (hi-dra´shun) the absorption of or combination with water.
1. The addition of water to a chemical molecule without hydrolysis.
2. of the fines network. All of these new methods were found to be simple, fast, and accurate for measurement. The finer the fines fractions, the more it contributed to slowing down the settling and increasing the viscosity of the fines suspension. View this paper online at http://www.tappi.org/index.asp?pid=34029&ch=1
Taegeun Kang is a research associate and Hannu Paulapuro is a professor at the Laboratory of Paper Technology, Helsinki University of Technology TKK redirects here. For other uses, see TKK (disambiguation).
Helsinki University of Technology is not to be confused with University of Helsinki.
Helsinki University of Technology (TKK) (Finnish: Teknillinen korkeakoulu; Swedish: Tekniska högskolan , P.O.Box 6300, FIN-02015, Finland. Email Kang at firstname.lastname@example.org.
ONLINE EXCLUSIVE CORROSION
MATERIALS ISSUES IN BLACK LIQUOR STEAM REFORMING/GASIFICATION
APPLICATION: This research will help improve the safety and reliability of black liquor steam reforming/gasification systems.
Steam reforming/gasification of the black liquor produced during wood pulping offers the potential for more efficient energy recovery, reduction of emissions, and improved safety. This technology is currently being implemented in two North American semichemical pulp mills. As might be expected in scaling up any process system, a number of problems have been encountered.
Degradation of metallic and refractory components has been observed in several areas. This paper presents the results of the examinations of a number of these damaged metallic components. It describes some of the material failures in the two low-temperature reformer/gasifier systems and then presents the solutions being applied or the approaches to finding a solution. View this paper online at http://www.tappi.org/index.asp?pid=34068&ch=1
James R. Keiser and Bruce A. Pint are with Oak Ridge National Laboratory Oak Ridge National Laboratory (ORNL) is a multiprogram science and technology national laboratory managed for the United States Department of Energy by UT-Battelle, LLC. ORNL is located in Oak Ridge, Tennessee, near Knoxville. , Oak Ridge, Tennessee Oak Ridge is an incorporated city in Anderson and Roane Counties in East Tennessee, about 25 miles northwest of Knoxville. Oak Ridge's population was 27,387 people at the 2000 census. , USA; Robert DeCarrera is with Georgia-Pacific Corporation, Atlanta, Georgia, USA; David G. Newport is with ThermoChem Recovery International, Baltimore, Maryland, USA; and Robert S. Rowbottom, now retired, was with Norampac, Mississauga, Ontario, Canada. Email Keiser at email@example.com.