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Topic: Kraft pulp


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In the News (Sun 16 Jun 19)

  
  Wood pulp - Wikipedia, the free encyclopedia
The chemicals used to bleach pulp have been a source of environmental concern, and recently the pulp industry has been using alternatives to chlorine, such as oxygen, ozone and hydrogen peroxide.
The use of wood pulp (and the introduction of steam power to the printing and paper making processes) led to cheaper paper and to the arrival of a new literary genre which we would later coin pulp fiction but were known to their contemporaries as dime novels or penny dreadfuls.
In the Kraft process, the largest volume byproduct from the pulping process is weak fl liquor.
en.wikipedia.org /wiki/Wood_pulp   (1133 words)

  
 Kraft process - Wikipedia, the free encyclopedia
The Kraft process (also known as Kraft pulping or sulfate process) is used in production of paper pulp and involves the use of caustic sodium hydroxide and sodium sulfide to extract the lignin from the wood fiber in large pressure vessels called digesters.
In the case of softwood (conifer) pulping, a soaplike substance is collected from the liquor during evaporation.
Kraft process differs from the sulfite process by using alkaline solution, which is less corrosive to the equipment.
en.wikipedia.org /wiki/Kraft_process   (307 words)

  
 Kraft Pulp Biobleaching and Mediated Oxidation of a Nonphenolic Substrate by Laccase from Streptomyces cyaneus CECT ...
Kraft Pulp Biobleaching and Mediated Oxidation of a Nonphenolic Substrate by Laccase from Streptomyces cyaneus CECT 3335
Enzymatic bleaching of the pulp with laccase and laccase-mediator
Kraft pulp bleaching and delignification by Trametes versicolor.
aem.asm.org /cgi/content/full/69/4/1953   (4398 words)

  
 Nalgrass: A Nonwood Fiber Source Suitable for Existing US Pulp Mills
Kraft pulping conditions for chips size and type evaluation (chips as is and presteamed 100 psig, 5 min).
Pulp from the 7/8-inch chip sample was beaten in a PFI mill to various freeness levels.
Based on the kraft and soda pulping results, it is recommended that mill scale trials be made and paper produced with the nalgrass material substituting for hardwood and possibly some of the softwood content of the furnish.
www.hort.purdue.edu /newcrop/ncnu02/v5-371.html   (2337 words)

  
 Products | Pulp & Paper   (Site not responding. Last check: 2007-10-31)
In Kraft pulping, almost 90 % of the wood lignin is solubilized in the cooking liquor.
The remaining lignin is primarily responsible for the brown color of the unbleached Kraft pulp and papers.
The concept of xylanase bleaching of Kraft pulp is based on the partial hydrolysis of xylan, which is the main component of the hemicellulose.
www.abenzymes.com /english/products/pulppaper.html   (657 words)

  
 Pulpwatch: Glossary and terms used in the pulp and paper industry   (Site not responding. Last check: 2007-10-31)
Commercially, pulp is usually described as air-dried when the moisture content of the pulp is 10%, although this percentage may be altered by contractual agreements between the buyer and seller.
Semi-chemical pulp Pulp produced in a two-stage process which involves the partial digestion of the wood with chemicals, followed by mechanical separation of the fibres in a disc refiner.
Although it produces a brighter pulp, with a higher yield, than kraft pulp, it is not as versatile as the kraft process, and the recovery of chemicals used in the sulphite process is more difficult.
www.pulpwatch.com /glossary.htm   (2892 words)

  
 Unasylva - No. 69 - Production of pulp and paper
As a consequence, the chemicals have to be recovered and, as the equipment needed for the recovery is complicated and expensive, kraft mills have to be built in large units with high capacity.
Unbleached chemical pulps from coniferous woods are obtained in a yield of about 60 percent of the wood, compared with 50 percent for ordinary sulphite and kraft pulps.
The pulp is obtained in a yield of 80 percent or higher and is of the same general character as groundwood.
www.fao.org /docrep/f3200e/f3200e04.htm   (3133 words)

  
 Process for producing kraft pulp for paper using nonionic surface active agents to improve pulp yield - Patent 4952277
In chemical pulping, the cooking of wood chips is usually terminated when the amounts of rejects in the wood pulp is reduced to an acceptable level.
In addition to use in traditional kraft or sulfate pulping processes, the surface active agents of the present invention can also be used in various modifications of the kraft process, such as in polysulfide processes, processes employing anthraquinone or anthraquinone derivatives such as salts of anthraquinone-2-sulfonate, soda-oxygen processes and soda-anthraquinone processes.
It is believed that in general the laboratory scale enhancements in pulp yield are predictive of similar improvements in mill scale processes, in that frequently the increases in yield observed in the mill are the same as or greater than those observed in the laboratory tests.
www.freepatentsonline.com /4952277.html   (3427 words)

  
 Pulp and Paper Technology - Stendal Kraft Pulp Mill - Germany
In 1999, the planned construction of a new kraft pulp mill in Germany was announced.
The Stendal pulp mill qualifies for support from the German Government in the form of federal and state loan guarantees, tax grants and investment incentives to the tune of €250 million.
The majority owner of the Stendal pulp mill is Mercer International Inc. with 63.5% of the joint venture.
www.pulpandpaper-technology.com /projects/stendal   (659 words)

  
 Kraft Pulp
The fibers initially liberated by kraft pulping usually are brown, similar to a typical grocery bag (paper type) or corrugated box.
The superior bonding potential of kraft pulps becomes evident when they are refined sufficiently to allow collapse of the lumen, delamination of the cell wall, and partial fibrillation of the surfaces.
In general, a kraft pulp blend that is rich in softwood fibers (average length about 3 mm) is easy to run on a paper machine and the paper is tough.
www4.ncsu.edu /~hubbe/KRFT.htm   (663 words)

  
 Pollution Prevention Assistance Division   (Site not responding. Last check: 2007-10-31)
Pulp is also sold to paper manufacturers that make paper, filter paper, or other specialty paper from pulp.
Pulp mills generally require a large amount of water in processing to remove lignin and bleaching byproducts.
The pulp is then transported to the paper machine where a pulp mat is formed on a screen.
www.gadnr.org /p2ad/Assets/Documents/ma_pulp1.htm   (2204 words)

  
 Pulp and Paper Production Basics
Pulp and paper is the third largest industrial polluter to air, water, and land in both Canada and the United States, and releases well over a hundred million kg of toxic pollution each year (National Pollutant Release Inventory, 1996).
But paper is an essential product, and we need to continue to look for improvements in pulp technology, new sources of fibre, and new technologies to get more out of the resources we use, and to avoid their use in the first place.
British Columbia's coastal pulp mills are the largest provincial source of airborne dioxins and furans, which are among the most toxic substances known.
www.rfu.org /cacw/basic.html   (974 words)

  
 Solving problems with pulp
In 1989, a world-scale pulp mill was proposed for Wesley Vale in northern Tasmania.
Kraft pulping has for many years been the most widely used process for producing paper with the strength and other qualities required by the high-quality paper market.
In studies overseas, MFO is a sensitive biomarker of pulp mill effluent exposure, and we began by developing methods for measuring MFO in sand flathead, a common Australian marine fish.
www.ffp.csiro.au /publicat/articles/pulp.htm   (3178 words)

  
 Unbleached Kraft Pulp
Kraft pulps tend to be more flexible than fibers produced by purely mechanical refining of pulp.
Kraft fibers tend to be more porous, compared to mechanical fibers.
Unbleached softwood kraft pulp contains wood rosin, making it practical to achieve a moderate degree of water resistance by addition of alum to the furnish.
www4.ncsu.edu /~hubbe/UBK.htm   (641 words)

  
 Chlorine free Bleaching of Eucalyptus Kraft Pulp   (Site not responding. Last check: 2007-10-31)
Pulp mills are improving the effluent treatment facilities and introducing process modifications to meet new chlorinated organics discharge limits.
The chlorine-free bleaching sequence of eucalypt kraft pulp involves oxygen pre-bleaching, a patented acid pulp treatment, followed by an oxidative extraction stage with oxygen and hydrogen peroxide, and peroxide stages.
When starting from kappa 20 pulp, the alternative sequences produced pulps with brightness in the range of 80% ISO, with lower extractives and pentosans contents, acceptable brightness reversion but significantly changed paper properties relatively to a reference chlorine-bleached pulp.
www.p2pays.org /ref/10/09471.htm   (662 words)

  
 Process for bio-bleaching of kraft pulp using bacterial consortia patent invention
A bonus of kraft pulping is that the chemicals can be recycled and re-used in the mill.
Kraft pulp is usually dark and is often bleached with chlorine compounds.
Kraft pulping removes lignin, dissolves and degrades hemicellulose without damaging cellulose Unfortunately, degradation products generated during pulping become trapped in the matrix and impart a brown color to Kraft pulp.
www.freshpatents.com /Process-for-bio-bleaching-of-kraft-pulp-using-bacterial-consortia-dt20060202ptan20060021724.php   (1934 words)

  
 Xylanase Lowers Chemical Load, Boosts Brightness of Kraft Pulp Pulp & Paper - Find Articles
Due to environmental pressures and market forces demanding low adsorbable organic halide (AOX) pulp, a softwood kraft pulp mill is investigating options to reduce chlorine and chlorine dioxide consumption in its bleach plant.
Mill scale trials showed that pulp quality as measured by tear, tensile and burst strength was not affected.
The objective of this work is to further substantiate that enzymes are effective in reducing the total equivalent chlorine with 0.4% hydrogen peroxide application in the first extraction stage.
www.findarticles.com /p/articles/mi_qa3636/is_200511/ai_n15868706   (870 words)

  
 Pulp & Paper Centre: Energy and Chemical Recovery
With today’s high energy and chemical costs and stringent environmental regulations that limit particulate and gaseous emissions, solid waste disposal, and mill effluent discharge, the need for improved recovery of chemicals and heating values from the pulping spent liquor has become a critical economic factor in kraft pulp mill operation.
The industrial relevance of the research projects and the high productivity of the research group have attracted significant support from kraft pulp mills and equipment suppliers, as well as matching funding from NSERC and other sources.
Eighteen pulp and paper related companies have joined the consortium to date, and a few more are expected to join soon.
www.pulpandpaper.utoronto.ca /Research/Kraft/index.html   (709 words)

  
 The Pulp Pollution Primer   (Site not responding. Last check: 2007-10-31)
The pulp and paper industry is one of the largest and most polluting industries in the world; it is the third most polluting industry in North America.
Pulp and paper is one of the world's largest industries, producing 178 million t of pulp, 278 million t of paper and paperboard, and consuming 670 million t of pulpwood.
The first stage required pulp mills to reduce the amount of organochlorines in waste water from an average of 10 kg per air-dried tonne (kg/adt) of pulp to 1.5 kg/adt by 1995.
www.rfu.org /PulpPrimer.htm   (4091 words)

  
 Pulp & Paper Company Links
Producer and supplier of lumber, plywood, kraft pulp and kraft paper.
Some 50 grades of paper and containerboard are manufactured, including such specialty converting grades as food packaging; construction papers; wrapping, masking, gumming, laminating, machine-glazed, creped and butcher papers; and papers available in a wide assortment of colors.
Manufacturer of market pulp and paper in the southern German states of Saxony and Thuringia in the former East Germany.
www.paperage.com /pulp_paper.html   (1830 words)

  
 Persistent Organochlorines in the Effluents from a Chlorine Bleached Kraft Integrated Pulp and Paper Mill in Southeast ...
The pulp is bleached to the brightness of 76-80% ISO.
Inadequate pulp washing may be the reason for the relatively high dioxin content remained in the bleached pulp and low content in the filtrate of the study mill.
The range of dioxin content found in both the bleached pulp and the bleaching filtrates of the study mill, is unexpectedly low considering the high rate of chlorine use in the used traditional conventional bleaching process.
www.environmental-expert.com /articles/article548/R99.htm   (3138 words)

  
 Pulp and Paper Technology - Zellstoff-Stendal Install PulpEye for Quality Control in the Fiberline
Since its launch in 2004, Eurocon's PulpEye pulp analyzer has rapidly been gaining a reputation as the ultimate analyser for the pulp and paper industry.
This is a breakthrough in bleached kraft pulp and PulpEye's first bleached kraft pulp installation in Europe.
Eurocon is a Swedish technical, processing consultancy company with many years of experience and a wide span of knowledge of the pulp and paper processing industry.
www.pulpandpaper-technology.com /contractors/measurement/eurocon/press5.html   (296 words)

  
 Pulp drying   (Site not responding. Last check: 2007-10-31)
Our services range from audits and capacity assessments, feasibility studies, capital cost estimates, and design development and specifications, to detailed design for both new installations and upgrades of existing equipment.
Rather than the more costly conventional pulp cleaning and thickening, the 7.8m wide pulp machine incorporates high consistency fine-slotted screening with centrifugal cleaning only of the screen rejects.
For the No. 4 pulp machine at this bleached kraft mill, we supplied preliminary engineering and detailed design for a reverse cleaning thickening system, one of the first of its kind in North America.
www.sandwell.com /Business/pnp/rp_pulpdry.htm   (163 words)

  
 Bleached Kraft Pulp - Boxboard Group - Cascades Inc.
Cascades FjordCell Inc. is a northern bleached softwood kraft pulp (NBSK) producer.
The pulp is made primarily from fl spruce chips, and offers excellent physical properties.
Cascades FjordCell inc. pulp is often used in the production of folding cartons, fine papers, tissue paper, etc… It is sold on the Quebec, Ontario, and American markets.
www.cascades.com /cas/en/1_0/1_0_1/1_0_1_1/1_0_1_1_3_3.jsp   (83 words)

  
 TAPPI -- leading technical association for the pulp, paper, and converting industry.
The bleachability of higher yield chemical pulps has been the subject of several reports, but little effort has been made to assess the changes in bleachability of these pulps across a bleaching sequence, and to correlate these changes with the varying composition and chemical structure of pulps during bleaching.
The PS pulp and reference kraft pulp had similar bleachabilities.
The different bleachabilities of pulps are attributable to the formation of a covalent bond between hexenuronic acid groups and lignin.
www.tappi.org /index.asp?pid=26029   (230 words)

  
 Northern bleached hardwood kraft pulp, softwood pulp, timberlands – Neenah Paper Inc.
In 2005, worldwide demand for hardwood market pulp was estimated to be approximately 18 million metric tons of which an estimated 1.7 million metric tons were northern bleached hardwood kraft pulp produced in Canada.
Bleached northern softwood kraft is recognized in the industry as premium pulp due to its properties of exceptional tensile strength and low coarseness, which provides an advantage in the production of paper and tissue products.
The pulp produced from our mill has unique properties that make it the pulp of choice for our customers, which in turn allow them to make the product of choice for theirs.
www.neenah.com /pulp/prod_info.aspx   (275 words)

  
 Enzymes in Bleacing of Kraft Pulp   (Site not responding. Last check: 2007-10-31)
during kraft pulping the residual brown-colored lignin must be removed and the
alternative in the bleaching of kraft pulp is treatment with enzymes.
as a pretreatment for bleaching of kraft pulp.
es.epa.gov /techpubs/3/14333.html   (93 words)

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