Pulp and paper industry, applications

Antti, H. Sjostrom, M. Wallbacks, L., Multivariate Calibration Models using NIR Spectroscopy on Pulp and Paper Industrial Applications /. Chemom. 1996, 10, 591-603. 

Maartens et al. [15] characterized adsorbed foulants calorimetrically and concluded that foulants in pulp and paper mill effluents are phenolic and hydrophobic in nature, a result corroborated by Puro et al. [9]. Maartens et al. also modified their membranes to make them more hydrophilic and achieved less fouling and better cleaning efficiency. Thus, pretreatment or modification of a membrane can improve its fouling resistance, its flux or retention, and can enhance its usability in pulp and paper industry applications [16]. 

Because high fluxes and the abdity to process streams containing suspended solids and fibers are often wanted in the pulp and paper industry, high-shear modules have been developed. Currently existing high-shear modules, excluding tubular modules, are modified plate and frame constructions. Both a cross-rotational module from Metso Paper and a vibration enhanced module (VSEP) from New Logic Inc. have been industrially used or tested in pulp and paper industry applications [48-51]. 

Wood is one of the oldest constructional materials. Historically it was important in world exploration and trade, and the defence of that trade, in the provision of merchant ships and navies. It was also important in the early days of railway engineering and in building construction. Although in many applications wood has been replaced by other materials, this renewable resource now supports the growing industries of manufactured wood products. Prominent amongst these are the panel materials chipboard, flake-board, strandboard, plywood and blockboard, hardboard and softboard, wood-cement products and the products of the very large pulp and paper industries. 

Biocides are also used in the pulp and paper industry for the protection of processing materials. The main biocides used in this application fall into the preservative range and can be different from others employed within the paper processing. 

The types of biocides used in this application vary from the rest of the pulp and paper industry. These require to be longer lasting, i.e. sometimes up to 1 years protection is storage tanks and hence fall into the category of preservatives. 

Dumont, G. A., Application of Advanced Control Methods in the Pulp and Paper Industry - A Survey, Automatica, 22 143 (1986)... 

The biotechnological potential of laccases—working with air and producing water as sole by-product—has led to applications from the textile to the pulp and paper industries, from food applications to bioremediation, as well as their use in organic synthesis. 

No doubt the cost of xylanolytic enzymes will be one of the factors determining their application in the pulp and paper industry as well as in other areas. Economically feasible xylanase production can be achieved in paper mills employing xylanase-positive transformants of common industrially used microorganisms that are capable of utilizing inexpensive carbon sources originating there. A substantial improvement in the production of xylanolytic systems can be expeaed from mutants of non-cellulolytic microorganisms that are resistant to catabolic repression. Such mutants usually exhibit hyperproduction of extracellular enzymes. 

Thermophilic Anaerobic Reactor Applications. Pulp and paper industries typically discharge warm (50°C) effluents, and conventional reactors operating under mesophilic conditions require cooling of such wastewaters. Attempts have been made periodically by various groups to investigate the possibility of applying thermophilic anaerobic processes to pulp and paper discharges, but to date there is no conclusive evidence to prove the superior performances of thermophilic reactors as compared to their mesophilic counterparts. 

As enzymatic oxidative transformation of the PVA polymer can act as a multiple simultaneous event on the polymer with concurrent chain fission by the appropriate enzymes, the polymer can be broken down into small oligomers that can be channelled into the primary metabolism. This picture is not complete because PVA is usually more or less acetylated. The DH is a pivotal factor in almost every aspect of PVA application. Surprisingly there are very few data dealing with the enzymes involved in the deacetylation of not fuUy hydrolysed PVA polymer. In technical processes, esterase enzymes are widely applied to deal with PVAc structures. A good example is from the pulp and paper industry [85], where PVAc, a component of stickies , is hydrolysed to the less sticky PVA. Esterases from natural sources are known to accept the acetyl residues on the polymer as substrate but little detailed knowledge exists about the identity of acetyl esterases in the PVA degradative environment [86]. 

Chlorine (from the Greek chloros for yellow-green ) is the most abundant halogen (0.19 w% of the earth s crust) and plays a key role in chemical processes. The chlor-alkali industry has been in operation since the 1890s and improvements in the technology are still important and noticeable, for example, the transition from the mercury-based technology to membrane cells [60]. Most chlorine produced today is used for the manufacture of polyvinyl chloride, chloroprene, chlorinated hydrocarbons, propylene oxide, in the pulp and paper industry, in water treatment, and in disinfection processes [61]. A summary of typical redox states of chlorine, standard potentials for acidic aqueous media, and applications is given in Scheme 2. 

Supercritical fluid extraction is a new separation technique that finds a number of applications in the natural products, biochemicals, food, pharmaceuticals, petroleum, fuel, and polymer industries (1-8). There is now an interest in applying this technology in the pulp and paper industry (9,10). In a recent comprehensive study on the interaction of supercritical fluids with lignocellulosic materials, it has been shown that lignin can be not only extracted from wood by reactive supercritical fluids but also separated as solid products in solvent-free form by reducing the extraction fluid pressure from a supercritical to sub critical level (11,12). 

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 application was growing rapidly in North America as of the late 1990s. 

The applications of CE analysis to inorganic anions are already numerous and are rapidly growing. The application ranges include, e.g. clinical chemistry [53], the pulp and paper industry [55], environmental samples [49], waste waters from processing plants [56], process control, industrial applications [43,57-59], explosive residue analysis [48], biological samples [60], or drugs and intermediates [61,62]. 

There are almost countless combinations of biocide blends being used around the world, each product using two or three or possibly more of the primary products discussed in the previous section. Many combinations were originally designed for the pulp and paper industry and have been later adapted for cooling water and other applications. 

H202 has been a popular oxidizing agent for decades in the textile, electronics and pulp and paper industries [125]. Applications of H202 in bulk chemistry have been reviewed in a few papers [126, 127]. In the H202 oxidation of benzene to phenol a selectivity of 90 + % has been reported with catalysts based on TS-1 [128] and/or Ti-MCM-41 [129] at reasonable conversion levels. However, H202 is too expensive compared to the frequently applied air and/or oxygen, and so there are no drivers for economically sustainable and economic application. 

Varied boiler firing configurations are found in hog fuel boiler applications, including dutch oven, fuel cell, spreader stoker with traveling or vibrating grates, and cyclone stoker types. As stated previously, the spreader stoker is the most widely used of these configurations. Spreader/stoker boilers in the pulp and paper industry often have an air swept spout added to the front of the boiler to feed bark down on top of the coal.14 Wood is puffed at one-... 

Allen, S.L. Allen, L.H. Flaherty, T.H. Defoaming in the Pulp and Paper Industry in Defoaming Theory and Industrial Applications, Garrett, P.R., Ed., Marcel Dekker New York, 1993, pp. 151-175. 

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