Wood pulping processes

CeUulose is the most abundant polymer, an estimated 10 t being produced aimuaUy by natural processes. SuppUes for the rayon industry can be obtained from many sources, but in practice, the wood-pulping processes used to supply the needs of the paper and board industries have been adapted to make the necessary speciaUy pure grade. Of the 3 x 10 t of wood used by the paper and board industry (13) in 1989, about 6 x 10 t were purified to provide the 2.5 x 10 t of dissolving pulp required by the viscose processes. 

Kraft Process. The dominant chemical wood pulping process is the kraft or sulfate process. The alkaline pulping Hquor or digesting solution contains about a three-to-one ratio of sodium hydroxide, NaOH, and sodium sulfide, Na2S. The name kraft, which means strength in German,... 

Ni-Cr-Fe-Mo Production of Handling acid Fuel element Wood pulp Processes where Pickling of... 

Although tannins and lignins have been available for well over 50 years (and perhaps twice as long), they remain very useful as low-cost, general-purpose particulate-matter dispersants. Both tannins and lignins are coproducts of the wood pulping process... 

Detailed discussion of the classical wood pulping processes - e.g., the Sulfite and Kraft processes - is available in the literature [14]. Pre-treatments that aim to facilitate the fermentation of lignocellulosic materials are also discussed elsewhere [49, 62-64]. 

Diterpene resin acids are abundantly produced in conifers of the pine family (Pinaceae) and in other plant species (Fig. 6). They are produced in the epithelial cells that surround the resin ducts that are found constitutively, or they are induced in the xylem upon wounding and are important for the physical and chemical plant defenses against herbivores and pathogens (18, 40). Industrially, diterpene resin acids are important chemicals for the naval stores industry, in printing inks, as potential antimicrobials and pharmaceuticals, and are byproducts of wood pulping processes. 

KRAFT PROCESS - A wood-pulping process in which sodium sulfate is used in the caustic soda pulp-digestion liquor. Also called Kraft pulping or sulfate pulping. 

Certain wood pulping processes for paper also require sulfuric acid, as do some textile and fiber processes (such as rayon and cellulose manufacture) and leather tanning. Other end uses for sulfuric acid include effluent/water treatment, plasticizers, dyestuffs, explosives, silicates for toothpaste, adhesives, rubbers, edible oils, lubricants, and the manufacture of food acids such as citric acid and lactic acid. 

Case study - Cooper River Watershed, Charleston, SC, USA The Cooper River Watershed empties into the Charleston Harbor on the southern Atlantic coast of the United States. In the lower reaches, the Cooper River is a highly industrialized and urbanized watershed with storm sewer and surface run-off impact. The river supports industries such as a wood pulp processing plant, a former naval shipyard, and a chromium mining/proccssing facility. In addition a number of fossil fuel refineries, storage facilities. 

Anttila J., Rousu R, Tanskanen J., Chemical recovery in a non-wood pulping process based on formic acid, Procedings Tappi Engineering Pulping and Environmental Confererute, Atlanta, 2006. 

The overall wastewater characteristics from wood pulping processes may vary seasonally because of the changes in characteristics of wood and variations in the temperature of the water. The volume and characteristics of the process wastewater depend upon the degree of water reuse, chemical recovery systems, and the type and quality of paper involved. 

An examination of the role of anthraquinone in alkaline wood-pulping processes has been carried out using cellobiose, glucose, and glycoaldehyde as model substrates. Each gave a wide range of acid products. 

Lignin (qv) is an abimdant renewable natural resource it accounts for over 20% of all organic matter and is second in abimdance only to cellulose. Approximately 46 million metric tons are isolated in the United States each year as a by-product of wood pulp processing. Its underutilization has often been described. 

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