Newsprint production

The effiuent/white water quality has to be controlled very exactly. COD increases with increasing pH. For flotation deinking of recovered paper the total chemical costs have a relatively high proportion of 15-20% of the overall DIP production costs. Yield rates up to 93 % for newsprint production are attainable. 

Process control with advanced measuring techniques and control strategies allowing the operators to continuously monitor the operation, see trends in paper quality and machine condition and take appropriate action Machine speed five decades ago the typical paper machine ran at a speed of about 300-350 mmirnh Today maximum machine speeds are above 2100 m mim for tissue machines, more than 1900 m min in newsprint production and above 1550 m mim for woodfree grades ( Fig. 6.1)... 

Westman L, Grundmark H, Petersson J (1989) Cationic polyelectrolytes as retentirai aids in newsprint production. Nord Pulp Pap Res J 4 113 116... 

Secondary Fiber. Increasing costs of taw fiber, legislative mandates for recycling (qv), and avadabdity of inexpensive waste papers have contfibuted to the increased use of recycled fibers. The use of secondary fiber in the United States has grown from 22% of pulp from all sources in 1978 to close to 31% (24 x 10 metric tons) in 1993 (3). Recycled fibers ate sometimes used in special writing papers, but the principal use is for the manufacture of linetboatd, newsprint, tissue, cereal boxes, towels, and molded paper products such as paper plates and egg cartons (see Packaging materials, containers AND INDUSTRIAL materials). 

Principal Uses. Groundwood pulp contains a considerable proportion (70—80 wt %) of fiber bundles, broken fibers, and fines in addition to the individual fibers. Principal uses of paper-grade pulps are in newsprint, magazine papers including coated pubHcation grades, board for folding and molded cartons, wallpapers, tissue, and other similar products. 

The TMP process is similar to the RMP process except that after chip washing, a steaming vessel is inserted to achieve the thermoplasticization of the lignin in the wood. The production of thermomechanical pulps increased dramatically after the introduction of this method in the early 1970s. Because these pulps can be substituted for conventional groundwood pulps in newsprint blends to give a stronger paper, lower quantities of the more expensive, lower yield chemical pulps are required. 

Its appeal Hes in the fact that synthesis gas can be produced from trash, municipal sewage, scrap wood, sawdust, newsprint, or other waste. The early work of Fischer and Tropsch on methanol synthesis showed that ethanol could be obtained in the process (165) and that by certain modifications the proportion of ethanol in the product could be increased (166). The Hterature concerning this method is extensive (167—176). The conditions that favor ethanol formation are 125—175°C and 1.42 MPa (14 atm) in the presence of reduction catalysts such as powdered iron. 

Kemppainen and Shonnard compared the production of ethanol via fermentation-based processes starting with two lignoceUulosic feedstocks virgin timber resources or recycled newsprint from an luban area. For this piupose, they coupled a software-aided simulation of the fermentation process with impact assessment software. 

Sulfite process wood pulp with or without bleaching used for products such as tissue papers, fine papers, and newsprint... 

Pulp manufacture by stone groundwood, mechanical refiner, thermo-mechanical, chemi-mechanical, or chemi-thermomechanical means for newsprint, coarse papers, tissue, molded fiber products, and fine papers... 

Mechanical pulping accounted for 9% of U.S. pulp production in 2000.1 Mechanically produced pulp is of low strength and quality. Such pulps are used principally for newsprint and other nonpermanent paper goods. Mechanical pulping uses physical pressures instead of chemicals to separate furnish fibers. The processes include the following ... 

This has historically involved only minimal use of chemical additives. The product is usually unsized and, because of its low cost, the use of polyelectrolytes for retention is not usually cost-effective. However, this situation is changing as a result of the trend towards limited filler inclusion and also the increased use of deinked waste paper. Newsprint is usually made in an acidic system due to the naturally low pH of groundwood pulp but, as more recycled fibre is used, the process may eventually become neutral. 

Paper products (newsprint, tissue, packaging, etc.) are made from pulps that consist of natural fibers derived from vascular plants such as trees, sugar cane, bamboo, and grass. The vascular fiber walls are composed of bundles of cellulose polymeric filaments. This long, linear glucose polymer is what paper is made from. The polymer has the structure shown in Scheme 8.18. 

The paper industry constitutes the largest single industrial market for starch in the world. If the world production of paper is about 235 MM tons, starch production for paper may be estimated at about 3 MM tons. This recognizes that large volume items such as newsprint and tissue are essentially non-starch users. 

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