Pulps papermaking

Gullichsen J and Fogelholm C-J (2000) Chemical pulping. Papermaking Science and Technology, Vol. 6A. Fapet Oy, Helsinki... 

Cetearyl alcohol Coconut alcohol Palm kernel alcohol Trideceth-23 raw material, sulfite pulp papermaking Dolomite... 

Uses Scale inhibitor and dispersant for water treatment, boiler water (food contact), cooling water, pulp/papermaking systems food-contact paper/paperboard Features Resist, to chlorine and compat. with most microbiological control agents Regulatory FDA 21CFR 173.310,176.170,176.180 Properties Cl. to si. hazy liq. m.w. 3300-3900 sp.gr. 1.20-1.25 dens. 10.0-10.4 lb/ gal vise. 500-2000 cps pH 3.0-3.5... 

Pulp-like olefin fibers are produced by a high pressure spurting process developed by Hercules Inc. and Solvay, Inc. Polypropylene or polyethylene is dissolved in volatile solvents at high temperature and pressure. After the solution is released, the solvent is volatilised, and the polymer expands into a highly fluffed, pulp-like product. Additives are included to modify the surface characteristics of the pulp. Uses include felted fabrics, substitution in whole or in part for wood pulp in papermaking, and replacement of asbestos in reinforcing appHcations (56). 

Neste patented an industrial route to a cellulose carbamate pulp (90) which was stable enough to be shipped into rayon plants for dissolution as if it were xanthate. The carbamate solution could be spun into sulfuric acid or sodium carbonate solutions, to give fibers which when completely regenerated had similar properties to viscose rayon. When incompletely regenerated they were sufficientiy self-bonding for use in papermaking. The process was said to be cheaper than the viscose route and to have a lower environmental impact (91). It has not been commercialized, so no confirmation of its potential is yet available. 

A cross-sectional view of kenaf is shown in Figure 3d. The ultimate cells are nearly cylindrical with thick cell walls. Kenaf fibers are shorter and coarser than those of jute. Both chemical (kraft) and mechanical pulps have been produced from kenaf, and successful demonstration mns of newsprint have been made for the Dallas Morning Nem, the St. Petersburg Times, and the Bakersfield Californian with a furnish of 82% kenaf chemithermomechanical pulp and 18% softwood kraft pulp. Kenaf fiber is also considered a substitute for jute and used in sacking, rope, twine, bags, and as papermaking pulp in India, Thailand, and the former Yugoslavia. RoseUe bleached pulp is marketed in Thailand. 

Defoamers. Foam is a common problem in papermaking systems (27). It is caused by surface-active agents which are present in the pulp slurry or in the chemical additives. In addition, partially hydrophobic soHd materials can function as foam stabilizers. Foam can exist as surface foam or as a combination of surface foam and entrained air bubbles. Surface foam usually can be removed by water or steam showers and causes few problems. Entrained air bubbles, however, can slow drainage of the stock and hence reduce machine speed. Another serious effect is the formation of translucent circular spots in the finished sheet caused by permanently entrained air. 

In 1945, cationic urea resins were introduced and quickly supplanted the anionic resins, since they could be used with any type of pulp (62). Although they have now become commodities, their use in the industry has been steadily declining as the shift towards neutral and alkaline papermaking continues. They are commonly made by the reaction of urea and formaldehyde with one or more polyethylene—polyamines. The stmcture of these resins is very compHcated and has not been deterrnined. Ammonia is evolved during the reaction, probably according to the following ... 

Enzymes in Pulp and Paper Production. Enzyme-modified starch has been used for adhesives to strengthen paper base and for surface coating. Developments since the late 1980s of further uses of enzymes in papermaking include pitch control and bleach boosting, (see Paper Pulp). 

Aliphatic acids or esters Mostly high-molecular-weight compounds diethyl phthalate laiiric acid Papermaking wood-pulp suspensions water-based paints food processing... 

Next, consider this family curve for a centrifugal pump used in the pulp and papermaking industry (Figure 7-13). 

We can take as an example worldwide papermaking that now consumes forests at a rate that is supposedly difficult to replace. Unlike the uses for wood, which are generally long-term use goods, most wood pulp paper is used for newspapers, business world, and periodicals or publications that are read and usually discarded, loading our solid waste disposal system and adding mountains to our trash. 

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