Industry pulp and paper

TABLE 3.12 Corrosion Failure Modes Along with the Frequency of Occurrence 

TABLE 3.13 Distribution of Stress Corrosion Cracking of Different Construction Materials  

Chlorides were involved mainly in the cracking of stainless steels, and caustics and nitrates were responsible for the cracking of steel. The studies reported that a 50-50 distribution between mechanical and corrosion failures was found to hold good. 

The paper-making process consists of various steps from pulp production, pulp processing and chemical recovery, pulp bleaching, and stock preparation to paper manufacturing. 

Pulp production is done by (i) mechanical pulping (ii) semichemical pulping, and (iii) chemical pulping. 

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Pulp and paper Pulp and paper industry Pulp and paper mills Pulp bleaching... 

Multicompartment dmm filters range in size from about 1 m to over 100 m they are widely used in mineral and chemical processing, in the pulp and paper industry, and in sewage and waste materials treatment. 

Pu/p and Paper Indust s Energy Ese-Cakndar Year 1986 New York, Apr. 20,1987 J. C. NiceUo, US. Pulp and Paper Industry s Energy Use-Calendar Year 1987 New York, May 17, SinnualEnerg) Eeview 1987 DOE/EIA-0384(87). U.S. Department of Energy, Energy Information Administration,... 

Two oxidants commonly used are chlorine and potassium permanganate. The Roe chlorine number, the uptake of gaseous chlorine by a known weight of unbleached pulp (ie. Technical Association of the Pulp and Paper Industry (TAPPl) Standard Method T202 ts-66) has been superseded by the simpler hypo number (ie, TAPPl Official Test Method T253 om-86), eg, chlorine consumption in treatment of the pulp with acidified sodium or calcium hypochlorite. 

Paper Technical Association of the Pulp and Paper Industry Technology Park/ Atlantic P.O. Box 105113 Atlanta, Ga. 30348 TAPPI Standards and TAPPI Yearbook cover all aspects of pulp (qv) and paper (qv) testing and associated standards. 

A. Mita and S. Kashiwabara, TAPPI Proceedings of the Pulping Conference, no. 2, Technical Association of the Pulp and Paper Industry, Adanta, Ga., 1987, p. 401. 

Oxygen is used to treat municipal wastewater and wastewater from the pulp and paper industry (see Aeration, water treatment Wastes, industrial Water). Many of these water appHcations can use VSA-produced oxygen (advantage /). Demonstration and development programs are in place that use oxygen to oxidize sludge from municipal waste and bum hazardous wastes and used tires (advantages 1—4). 

The wide range of types of paper products results in a variety of sludges. SoHd wastes result from several sources within the mill, eg, bark, sawdust, dirt, knots, pulpwood rejects, flyash, cinders, slag, and sludges. Sludges often are disposed of in combination with residuals from other sources. Approximately 300 kg of soHd waste per ton of finished product is generated by the pulp and paper industry. 

H. S. Dugal, "Environmental Laws and Their Impact on Mill Processes," paper presented at The Third Symposium on Corrosion in Pulp and Paper Industry, May 1980. 

Tappi Press Books, Technical Association of the Pulp and Paper Industry, Atianta, Ga. 

Lists of the manufacturers of each type of product used by the paper industry are available (6). Surveys of chemical suppHers for the U.S. and Canadian pulp and paper industries have been pubHshed (7). 

Sulfur, another inorganic petrochemical, is obtained by the oxidation of hydrogen sulfide 2H2S + O2 — 2H2 0 + 2S. Hydrogen sulfide is a constituent of natural gas and also of the majority of refinery gas streams, especially those off-gases from hydrodesulfurization processes. A majority of the sulfur is converted to sulfuric acid for the manufacture of fertilizers and other chemicals. Other uses for sulfur include the production of carbon disulfide, refined sulfur, and pulp and paper industry chemicals. 

Several industries are highly dependent on cheap electric power. These include the aluminum industry, the Portland cement industry, electrochemical industries such as plating and chlorine production, the glass industry, and the pulp and paper industry. Other industries such as the petrochemical industry, which is highly competitive, depend on low priced power. About two-thirds of the cost of producing ammonia is electrical cost. 

The pulp and paper industry and potable and wastewater treatment industry are the principal markets for aluminum sulfate. Over half of the U.S. aluminum sulfate produced is employed by the pulp and paper industry. About 37% is used to precipitate and fix rosin size on paper fibers, set dyes, and control slurry pH. Another 16% is utilized to clarify process waters. The alum sold for these purposes is usually Hquid alum. It is frequendy acidic as a result of a slight excess of H2SO4. Aluminum sulfate consumption by the pulp and paper industry is projected to remain constant or decline slightly in the near term because of more efficient use of the alum and an increased use of alkaline sizing processes (13). 

J. P. Weidner, ed.. Wet Strength in Paper and Paper Board, Monograph Series, No. 29, Technical Association of Pulp and Paper Industry, New York,... 

Closed-Mill Concept. The closed-mill concept, or water circuit closure, has been studied by the pulp and paper industry for many years. In some parts of the paper manufacturing process, up to 98% of the water is recycled within the process, eg, the wet end of the paper machine. However, in the pulp mill, especiaUy kraft mills, effluents are produced owing to the need to purge from the system various metals that come in with the wood, as weU as organic by-products from the pulping process, additives, and especially chloride ions that originate in the bleach plant. 

Uses. The dominant use of sulfur dioxide is as a captive intermediate for production of sulfuric acid. There is also substantial captive production in the pulp and paper industry for sulfite pulping, and it is used as an intermediate for on-site production of bleaches, eg, chlorine dioxide or sodium hydrosulfite (see Bleaching agents). There is a substantial merchant market for sulfur dioxide in the paper and pulp industry. Sulfur dioxide is used for the production of chlorine dioxide at the paper (qv) mill site by reduction of sodium chlorate in sulfuric acid solution and also for production of sodium dithionite by the reaction of sodium borohydride with sulfur dioxide (315). This last appHcation was growing rapidly in North America as of the late 1990s. 

Titanium metal is especially utilised ia environments of wet chlorine gas and bleaching solutions, ie, in the chlor—alkaH industry and the pulp and paper industries, where titanium is used as anodes for chlorine production, chlorine—caustic scmbbers, pulp washers, and CI2, CIO2, and HCIO storage and piping equipment (see Alkali and cm ORiNE products Paper Pulp). 

The BPT is defined as the level of treatment that has been proven to be successful for a specific industrial category and that is currendy in fuU-scale operation. Sufficient data exist for this level of treatment so that it can be designed and operated to achieve a level of treatment consistendy and with rehabUity. For example, in the pulp and paper industry, BPT has been defined as biological treatment using the aerated lagoon or the activated sludge process with appropriate pretreatment. 

The BAT is defined as the level of treatment beyond BPCTCA that has been proven feasible in laboratory and pUot studies and that is, in some cases, in fuU-scale operation. BAT in the pulp and paper industry may include such processes as filtration, coagulation for color removal, and improved in-plant control to reduce the wasteload constituents. 

Pleach Plant Operations Short Course Notes, Technical Association of the Pulp and Paper Industry (TAPPI) Press, Atianta, Ga., 1983—1991. Successive editions pubhshed at intervals of slightly more than one year. Each is a collection of monographs on various aspects of pulp bleaching technology. Eadier editions replace the words "short course" with "seminar" in the tide. Collectively, probably the best available pulp bleaching text. 

Production of Sodium Borohydride. In the pulp and paper industry, sodium borohydride is used to generate sodium hydrosulfite (sodium dithionite), a bleaching agent, from sodium bisulfite. Methyl borate is used as an intermediate in the production of sodium borohydride (33). 

The most comprehensive set of test methods for calcium carbonate has been assembled by the Pulverized Limestone Division of the National Stone Association. Methods for particle size, brightness, +325 mesh (44 -lm), and percentage of calcium carbonate have been pubflshed standards are available and have been well characterized (5). The Technical Association of the Pulp and Paper Industry (TAPPl) has pubflshed methods for calcium carbonate used in the paper industry (6). 

Of the sodium sulfate produced in the United States the paper industry consumes 36%, 45% is used in detergents, and 10% in the glass industry (72). Powdered detergents are on the decline in favor of Hquids that do not use sodium sulfate. Since the pulp and paper industry are also using less, the price of sodium sulfate is fluctuating (see Sodium compounds). 

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