2 edition of Studies in sulphite pulping found in the catalog.
Studies in sulphite pulping
F. H. Yorston
|Statement||by F.H. Yorston.|
|Series||Canada. Forest Service. Bulletin, 97|
|LC Classifications||SD13 .A2 no. 97|
|The Physical Object|
|Pagination||80 p. incl. tables, diagrs.|
|Number of Pages||80|
|LC Control Number||44003356|
Traditional sulfite pulping has been in industry practice for more than a century and can be operated over a wide range of pH and temperature. And the active reagents in sulfite pretreatment liquor are also depended on the pH of the pretreatment temperature [ 12 ]. deresination options in sulphite pulping Three methods for improved deresination of sulphite pulps were evaluated, namely, alkaline washing, enzyme treatment, and pulp fractionation. Alkaline washing appears to come at a high cost, because caustic is expensive and affects cellulose chain length, as indicated by lower viscosity of the pulps.
Pulp mills generate paper and other pulp mill products we use many times a day. North American pulp mills create these products primarily from planted forests and sustainably manage natural forests. More than 60% of the paper products produced in North America are ultimately recycled, and more than 35% of new paper products come from recycled. Very high yield sulphite pulps were produced by cooking black spruce wafers in pulping liquors at pH 7 or 10, containing % (on O.D. wood) of soluble anthraquinone (SAQ). These pulps had better strength properties relative to controls prepared without SAQ, breaking length and burst index being greater, on average, by 20%.
Cold soda pulp process: The wood chips are treated with diluted caustic solution (2 to 6%) at room temperature and softened the chips are reduced to pulp by disc machine. Chemi groundwood pulping process: In this process, high-density hardwood is digested in neutral sulfite liquor and then reduced to pulp by grinding. Pulping. Chemical pulping involves dissolving lignin in order to extract the cellulose from the wood fiber. The different processes of chemical pulping include the Kraft process, which uses caustic soda and sodium sulfide and is the most common; alternatively, the use of sulfurous acid is known as the sulfite process, the neutral sulfite semichemical is treated as a third process separate from.
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H.L. Hintz, in Encyclopedia of Materials: Science and Technology, Sulfite and Solvent Pulping Processes. In sulfite pulping, usually conducted under acid or neutral conditions, sulfur dioxide and/or bisulfite ions react with lignin to produce water-soluble sulfonated lignins that are degraded by acid hydrolysis e pulping can be controlled to produce pulps over a wide.
Sulfite-oxidizing enzymes (SOE) are found in a wide variety of organisms, where they play the crucial role of protecting from sulfite-induced damage. 59,60 The oxo-molybdenum centers in SOE are five-coordinate square pyramidal with two coordination sites occupied by a pyranopterin dithiolene cofactor and a third equatorial site is occupied by a cysteine S.
Extensive EPR studies combined with. Sulfite process, sulfite also spelled Sulphite, chemical process for the manufacture of paper pulp that employs an acid Studies in sulphite pulping book solution to soften the wood material by removing the lignin from the e cooking liquor used in the process consists of free sulfur dioxide obtained by the burning of sulfur or by the roasting of iron pyrites, dissolved in water at a concentration of.
Among the general aspects of sulphite pulping, the common delignification features (including delignification kinetics), the selectivity of delignification and typical pulping operations are.
Acid Sulfite Pulping Process Description - The production of acid sulfite pulp proceeds similarly to kraft pulping, except that different chemicals are used in the cooking liquor. In place of the caustic solution used to dissolve the lignin in the wood, sulfurous acid is employed.
To buffer the cooking solution, a bisulfite of File Size: KB. The sulfite process produces wood pulp that is almost pure cellulose fibers by treating wood chips with solutions of sulfite and bisulfite ions.
These chemicals cleave the bonds between the cellulose and lignin components of the lignocellulose. A variety of sulfite/bisulfite salts are used, including sodium (Na +), calcium (Ca 2+), potassium (K +), magnesium (Mg 2+), and ammonium (NH 4 +).
Summary. A mathematical model for neutral sulfite pulping process was derived. This model represented by a linear logarithmic relationship of the main pulping characteristics (yield and lignin content) to time and temperature parameters, both determined by the H-factor, is expressed by a logarithmic straight line equation.
pulping process is shown in figure Mechanical, semichemical, and sulfite pulp mills differ in detail, particularly in wood preparation, fiber separation, and bleaching, but many of the downstream refining, bleaching, and papermaking processes are similar.
In addition to the primary steps in pulp and paper. Pulp and paper industry is considered as one of the most polluter industry in the world (Thompson et al., ; Sumathi & Hung, ).
The production process consists two main steps: pulping and bleaching. Pulping is the initial stage and the source of the most pollutant of this industry. A study investigated the origin of the losses of ethylene glycol during pulping.
Glycerols have also been used in pulp production [ 49, ]. Thus, treating Ailanthus altissima and Spruce orientalis wood with glycerol provided optimal delignification results in the presence of an alkali, which, however, led to increased cellulose.
This study investigates the requirements for modeling of acid sulfite pulping with regard to the recovery of cooking chemicals, especially SO2. Such a model has to predict the temporal change of SO2 distribution on solid, liquid and gaseous phase in the digester throughout the whole pulping process, dependent on the pulping.
pulping, we differentiate between sulphate and sulphite pulp, depending on the chemicals used. The yield of chemical pulping amounts to approximately 50%.
The fibres in the resulting pulp are very clean and undamaged. The wood pulp produced by this process is called woodfree. It is this type of pulp which is used for all Sappi fine papers.
THE second chemical method for pulp making was the sulfite process, invented by Benjamin C. Tilghman, who experimented with the effect of sulfurous acid on wood shortly after the Civil War.
His digester was a rotating, horizontal cylinder lined with lead and about 50 feet long by 3 feet in diameter. - It should have pulping conditions that do not degrade cellulose and dissolved hemicelluloses.
- It should be capable of solubilizing most of the lignin with very little loss of cellulose and only a modest loss of hemicelluloses. - It should not require higher temperatures, pressures or pulping times than used in kraft and sulphite pulping.
Odom, J. J., TAPPI Pulping Conf. (Orlando) "Sulfite Pulping: Probable Replacement of the Kraft Process", (Book 2): (Nov. ). Wood Sources for the Port Huon Mill: NSSC Pulping of. In ASAM pulping with the usage of alkali and sodium sulfite (Na 2 SO 3), the depolymerization properties of kraft process and the hydrophilicity-creating properties of sulfite process were illustrated (Shukry et al.
In this study, the effect of cooking parameters on bamboo pulp yield, kappa number, and initial CSF have been studied. EPA/OOS BACKGROUND DOCUMENT: ACID SULFITE PULPING by Al Linero Environmental Science and Engineering, Inc. University Station Gainesville, Florida Contract No.
Task Order No. 14 EPA Project Officer: Thomas F. Lahre Prepared for ENVIRONMENTAL PROTECTION AGENCY Office of Air and Waste Management Office of Air Quality Planning and.
The paper is not categorised as sulphite or sulfate process. The pulping is categorised as sulphite or sulfate process. To put the things simple sulphite is acidic pulpig process mostly preferred for rayon grade pulp for cloth manufacturer. Rarely. In acid-sulphite pulping the effect was less than in kraft, while in acid-chlorite pulping the effect was smallest.
Thus the results confirmed in general the previously reported trends based on microscopic observation. However, in earlier work there was no topochemical difference found in acid-chlorite pulping, even at high delignification.
However, studies showed that more than 90% of these fines could be recovered by flotation (Enke ). For example, after a separate alkaline treatment, fines from European spruce and hardwood sulfite pulps were rendered fairly harmless and could be recycled to the bulk of the pulp in the alkaline extraction stage of bleaching.
No separate. chemistry of the sulphite process Download chemistry of the sulphite process or read online books in PDF, EPUB, Tuebl, and Mobi Format. Click Download or Read Online button to get chemistry of the sulphite process book now.
This site is like a library, Use .Pacon Smart-Stack Sulphite Acid-Free Non-Toxic Construction Paper, 76 lb, 12" x 18", Assorted Color $ $ 02 ($/Each Set) Get it as soon as Tue, Jul 7.The resulted pulp often called as chemical pulp, referring to the chemical pulping process.
Kraft, sulfite and soda are three major chemical pulping methods known today. Kraft Pulping Kraft process are often called kraft pulping is the most used chemical pulping in the pulp and paper industry. The main reason for the dominance of the kraft.