- •Recovered Paper and Recycled Fibers
- •Isbn: 3-527-30999-3
- •Introduction
- •Isbn: 3-527-30999-3
- •Isbn: 3-527-30999-3
- •2006, Isbn 3-527-30997-7
- •Volume 1
- •Isbn: 3-527-30999-3
- •4.1 Introduction 109
- •4.2.5.1 Introduction 185
- •4.3.1 Introduction 392
- •5.1 Introduction 511
- •6.1 Introduction 561
- •6.2.1 Introduction 563
- •6.4.1 Introduction 579
- •Volume 2
- •7.3.1 Introduction 628
- •7.4.1 Introduction 734
- •7.5.1 Introduction 777
- •7.6.1 Introduction 849
- •7.10.1 Introduction 887
- •8.1 Introduction 933
- •1 Introduction 1071
- •5 Processing of Mechanical Pulp and Reject Handling: Screening and
- •1 Introduction 1149
- •Isbn: 3-527-30999-3
- •Isbn: 3-527-30999-3
- •Isbn: 3-527-30999-3
- •Isbn: 3-527-30999-3
- •Introduction
- •Introduction
- •Isbn: 3-527-30999-3
- •1 Introduction
- •1 Introduction
- •1 Introduction
- •1 Introduction
- •1 Introduction
- •1 Introduction
- •150.000 Annual Fiber Flow[kt]
- •1 Introduction
- •1 Introduction
- •Introduction
- •Isbn: 3-527-30999-3
- •Void volume
- •Void volume fraction
- •Xylan and Fiber Morphology
- •Initial bulk residual
- •4.2.5.1 Introduction
- •In (Ai) Model concept Reference
- •Initial value
- •Validation and Application of the Kinetic Model
- •Inititial
- •Viscosity
- •Influence on Bleachability
- •Impregnation
- •Impregnation
- •Impregnation
- •Impregnation
- •Impregnation
- •Impregnation
- •Impregnation
- •Impregnation
- •Impregnation
- •Impregnation
- •Introduction
- •International
- •Impregnation
- •Influence of Substituents on the Rate of Hydrolysis
- •140 116 Total so2
- •Xylonic
- •Viscosity Brightness
- •Xyl Man Glu Ara Furf hoAc XyLa
- •Initial NaOh charge [% of total charge]:
- •Introduction
- •Isbn: 3-527-30999-3
- •Introduction
- •Isbn: 3-527-30999-3
- •Introduction
- •Introduction
- •Isbn: 3-527-30999-3
- •Introduction
- •Xylosec
- •Xylan residues
- •Viscosity
- •Introduction
- •Viscosity
- •Viscosity
- •Introduction
- •Initiator Promoter Inhibitor
- •Viscosity
- •Viscosity
- •Viscosity
- •Introduction
- •Viscosity
- •Introduction
- •Intra-Stage Circulation and Circulation between Stages
- •Implications of Liquor Circulation
- •Vid Chalmers Tekniska
- •Introduction
- •It is a well-known fact that the mechanical properties of the viscose fibers
- •Increase in the low molecular-weight fraction [2]. The short-chain molecules represent
- •Isbn: 3-527-30999-3
- •In the cooking process or, alternatively, white liquor can be used for the cold
- •Is defined as the precipitate formed upon acidification of an aqueous alkaline solution
- •934 8 Pulp Purification
- •8.2 Reactions between Pulp Constituents and Aqueous Sodium Hydroxide Solution 935
- •Is essentially governed by chemical degradation reactions involving endwise depolymerization
- •80 °C [12]. Caustic treatment: 5%consistency ,
- •30 Min reaction time, NaOh concentrations:
- •8.2 Reactions between Pulp Constituents and Aqueous Sodium Hydroxide Solution
- •80 °C is mainly governed by chemical degradation reactions (e.G. Peeling reaction).
- •Investigated using solid-state cp-mas 13c-nmr spectroscopy (Fig. 8.4).
- •Indicates cleavage of the intramolecular hydrogen bond between o-3-h and o-5′,
- •8 Pulp Purification
- •Interaction between alkali and cellulose, a separate retention tower is not really
- •In the following section.
- •3% In the untreated pulp must be ensured in order to avoid a change in the supramolecular
- •8.3 Cold Caustic Extraction
- •Xylan content [%]
- •8 Pulp Purification
- •Is calculated as effective alkali (ea). Assuming total ea losses (including ea consumption
- •Xylan content [%]
- •8.3 Cold Caustic Extraction
- •120 °C (occasionally 140 °c). As mentioned previously, hce is carried out solely
- •Involved in alkaline cooks (kraft, soda), at less severe conditions and thus avoiding
- •8.4Hot Caustic Extraction 953
- •954 8 Pulp Purification
- •120 Kg NaOh odt–1, 90–240 min, 8.4 bar (abs)
- •8.4Hot Caustic Extraction 955
- •956 8 Pulp Purification
- •Into the purification reaction, either in the same (eo) or in a separate stage
- •960 8 Pulp Purification
- •8.4.1.5 Composition of Hot Caustic Extract
- •8.4Hot Caustic Extraction 961
- •Isbn: 3-527-30999-3
- •Xyloisosaccharinic acid
- •Inorganicsa
- •Inorganic compounds
- •Value (nhv), which better reflects the actual energy release, accounts for the fact
- •968 9 Recovery
- •It should be noted that the recycling of bleach (e.G., oxygen delignification) and
- •9.1 Characterization of Black Liquors 969
- •9.1.2.1 Viscosity
- •9.1.2.3 Surface Tension
- •9.1.2.5 Heat Capacity [8,11]
- •9.2 Chemical Recovery Processes
- •Is described by the empirical equation:
- •9 Recovery
- •Vent gases from all areas of the pulp mill. From an environmental perspective,
- •9.2.2.1 Introduction
- •In the sump at the bottom of the evaporator. The generated vapor escapes
- •Incineration, whereas sulphite ncg can be re-used for cooking acid preparation.
- •9 Recovery
- •Values related to high dry solids concentrations. The heat transfer rate is pro-
- •9.2 Chemical Recovery Processes
- •9.2.2.3 Multiple-Effect Evaporation
- •7% Over effects 4 and 5, but more than 30% over effect 1 alone.
- •9.2 Chemical Recovery Processes
- •Increasing the dry solids concentration brings a number of considerable advantages
- •9.2.2.4 Vapor Recompression
- •Is driven by electrical power. In general, vapor coming from the liquor
- •Vapor of more elevated temperature, thus considerably improving their performance.
- •9 Recovery
- •Is typically around 6 °c. The resulting driving temperature difference
- •Is low, and hence vapor recompression plants require comparatively large heating
- •Vapor recompression systems need steam from another source for start-up.
- •9 Recovery
- •Its temperature is continuously falling to about 180 °c. After the superheaters,
- •In the furnace walls, and only 10–20% in the boiler bank. As water turns into
- •9.2.3.1.2 Material Balance
- •Is required before the boiler ash is mixed. In addition, any chemical make-up
- •In this simplified model, all the potassium from the black liquor (18 kg t–1
- •Values for the chemicals in Eq. (11) can be inserted on a molar basis, equivalent
- •9.2 Chemical Recovery Processes
- •Input/output
- •9 Recovery
- •9.2.3.1.3 Energy Balance
- •In the black liquor, from water formed out of hydrogen in organic material, and
- •9.2 Chemical Recovery Processes
- •9.2.3.2 Causticizing and Lime Reburning
- •9.2.3.2.1 Overview
- •9.2.3.2.2 Chemistry
- •986 9 Recovery
- •Insoluble metal salts are kept low. Several types of filters with and without lime
- •Is, however, not considered a loss because some lime mud must be
- •988 9 Recovery
- •In slakers and causticizers needs special attention in order to avoid particle disintegration,
- •9.2 Chemical Recovery Processes 989
- •Ing disks into the center shaft, and flows to the filtrate separator. There, the white
- •9.2.3.2.4 Lime Cycle Processes and Equipment
- •It is either dried with flue gas in a separate, pneumatic lime mud dryer or is fed
- •990 9 Recovery
- •Its temperature falls gradually. Only about one-half of the chemical energy in the
- •9.2.3.3.2 Black Liquor Gasification
- •Inorganics leave the reactor as solids, and into high-temperature techniques,
- •In the bed. Green liquor is produced from surplus bed solids. The product gas
- •992 9 Recovery
- •Incremental capacity for handling black liquor solids. The encountered difficulties
- •10% Of today’s largest recovery boilers. When the process and material issues are
- •9.2 Chemical Recovery Processes 993
- •9.2.3.3.3 In-Situ Causticization
- •Is still in the conceptual phase, and builds on the formation of sodium titanates
- •9.2.3.3.4 Vision Bio-Refinery
- •Into primary and secondary recovery steps. This definition relates to the recovery
- •994 9 Recovery
- •Is largely different between sulfite cooking bases. While magnesium and
- •Introduction
- •In alkaline pulping the operation of the lime kiln represents an emission source.
- •Isbn: 3-527-30999-3
- •Is by the sophisticated management of these sources. This comprises their collection,
- •Ions, potassium, or transition metals) in the process requires the introduction
- •Industry”. Similarly guidelines for a potential kraft pulp mill in Tasmania [3]
- •Initially, the bleaching of chemical pulp was limited to treatment with hypochlorite
- •In a hollander, and effluent from the bleach plant was discharged without
- •In a heh treatment and permitted higher brightness at about 80% iso (using
- •Increasing pulp production resulted in increasing effluent volumes and loads.
- •10.2 A Glimpse of the Historical Development 999
- •It became obvious that the bleaching process was extremely difficult to operate in
- •In a c stage was detected as aox in the effluent (50 kg Cl2 t–1 pulp generated
- •1% Of the active chlorine is converted into halogenated compounds (50 kg active
- •In chlorination effluent [12] led to the relatively rapid development of alternative
- •1000 10 Environmental Aspects of Pulp Production
- •10.2 A Glimpse of the Historical Development
- •In 1990, only about 5% of the world’s bleached pulp was produced using ecf
- •64 Million tons of pulp [14]. The level of pulp still bleached with chlorine
- •10 000 Tons. These are typically old-fashioned, non-wood mills pending an
- •In developed countries, kraft pulp mills began to use biodegradation plants for
- •10 Environmental Aspects of Pulp Production
- •Indeed, all processes are undergoing continual development and further improvement.
- •Vary slightly different depending upon the type of combustion unit and the fuel
- •10.3Emissions to the Atmosphere
- •Volatile organic
- •In 2004 for a potential pulp mill in Tasmania using “accepted
- •10 Environmental Aspects of Pulp Production
- •Is woodyard effluent (rain water), which must be collected and treated biologically
- •10.4 Emissions to the Aquatic Environment
- •Is converted into carbon dioxide, while the other half is converted into biomass
- •Into alcohols and aldehydes; (c) conversion of these intermediates into acetic acid and
- •10 Environmental Aspects of Pulp Production
- •In North America, effluent color is a parameter which must be monitored.
- •It is not contaminated with other trace elements such as mercury, lead, or cadmium.
- •10.6 Outlook
- •Increase pollution by causing a higher demand for a chemical to achieve identical
- •In addition negatively affect fiber strength, which in turn triggers a higher
- •Introduction
- •2002, Paper-grade pulp accounts for almost 98% of the total wood pulp production
- •Important pulping method until the 1930s) continuously loses ground and finds
- •Importance in newsprint has been declining in recent years with the increasing
- •Isbn: 3-527-30999-3
- •Virtually all paper and paperboard grades in order to improve strength properties.
- •In fact, the word kraft is the Swedish and German word for strength. Unbleached
- •Importance is in the printing and writing grades. In these grades, softwood
- •In this chapter, the main emphasis is placed on a comprehensive discussion of
- •1010 11 Pulp Properties and Applications
- •Is particularly sensitive to alkaline cleavage. The decrease in uronic acid content
- •Xylan in the surface layers of kraft pulps as compared to sulfite pulps has been
- •80% Cellulose content the fiber strength greatly diminishes [14]. This may be due
- •Viscoelastic and capable of absorbing more energy under mechanical stress. The
- •11.2 Paper-Grade Pulp 1011
- •Various pulping treatments using black spruce with low fibril
- •In the viscoelastic regions. Fibers of high modulus and elasticity tend to peel their
- •1012 11 Pulp Properties and Applications
- •11.2 Paper-Grade Pulp
- •Viscosity mL g–1 793 635 833 802 1020 868 1123
- •Xylose % od pulp 7.3 6.9 18.4 25.5 4.1 2.7 12.2
- •11 Pulp Properties and Applications
- •Inorganic Compounds
- •11.2 Paper-Grade Pulp
- •Insight into many aspects of pulp origin and properties, including the type of
- •Indicate oxidative damage of carbohydrates).
- •In general, the r-values of paper pulps are typically at higher levels as predicted
- •Is true for sulfite pulps. Even though the r-values of sulfite pulps are generally
- •Is rather unstable in acid sulfite pulping, and this results in a low (hemicellulose)
- •11 Pulp Properties and Applications
- •Ing process, for example the kraft process, the cellulose:hemicellulose ratio is
- •Increases by up to 100%. In contrast to fiber strength, the sheet strength is highly
- •Identified as the major influencing parameter of sheet strength properties. It has
- •In contrast to dissolving pulp specification, the standard characterization of
- •Is observed for beech kraft pulp, which seems to correlate with the enhanced
- •11.2 Paper-Grade Pulp
- •11 Pulp Properties and Applications
- •Is significantly higher for the sulfite as compared to the kraft pulps, and indicates
- •11.2 Paper-Grade Pulp
- •Xylan [24].
- •11 Pulp Properties and Applications
- •11.2 Paper-Grade Pulp
- •11 Pulp Properties and Applications
- •Introduction
- •Various cellulose-derived products such as regenerated fibers or films (e.G.,
- •Viscose, Lyocell), cellulose esters (acetates, propionates, butyrates, nitrates) and
- •In pulping and bleaching operations are required in order to obtain a highquality
- •Important pioneer of cellulose chemistry and technology, by the statement that
- •11.3 Dissolving Grade Pulp
- •Involves the extensive characterization of the cellulose structure at three different
- •Is an important characteristic of dissolving pulps. Finally, the qualitative and
- •Inorganic compounds
- •11 Pulp Properties and Applications
- •11.3.2.1 Pulp Origin, Pulp Consumers
- •Include the recently evaluated Formacell procedure [7], as well as the prehydrolysis-
- •11.3 Dissolving Grade Pulp
- •Viscose
- •11 Pulp Properties and Applications
- •11.3.2.2 Chemical Properties
- •11.3.2.2.1 Chemical Composition
- •In the polymer. The available purification processes – particularly the hot and cold
- •11.3 Dissolving Grade Pulp
- •In the steeping lye inhibits cellulose degradation during ageing due to the
- •Is governed by a low content of noncellulosic impurities, particularly pentosans,
- •Increase in the xylan content in the respective viscose fibers clearly support the
- •11.3 Dissolving Grade Pulp
- •Instability. Diacetate color is measured by determining the yellowness coefficient
- •Xylan content [%]
- •11 Pulp Properties and Applications
- •Xylan content [%]
- •11.3 Dissolving Grade Pulp
- •11.3 Dissolving Grade Pulp
- •Is, however, not the only factor determining the optical properties of cellulosic
- •In the case of alkaline derivatization procedures (e.G., viscose, ethers). In industrial
- •11.3 Dissolving Grade Pulp
- •Viscose
- •Viscose
- •In order to bring out the effect of mwd on the strength properties of viscose
- •Imitating the regular production of rayon fibers. To obtain a representative view
- •11 Pulp Properties and Applications
- •Viscose Ether (hv) Viscose Acetate Acetate
- •Xylan % 3.6 3.1 1.5 0.9 0.2
- •1.3 Dtex regular viscose fibers in the conditioned
- •11.3 Dissolving Grade Pulp
- •Is more pronounced for sulfite than for phk pulps. Surprisingly, a clear correlation
- •Viscose fibers in the conditioned state related to the carbonyl
- •1038 11 Pulp Properties and Applications
- •In a comprehensive study, the effect of placing ozonation before (z-p) and after
- •Increased from 22.9 to 38.4 lmol g–1 in the case of a pz-sequence, whereas
- •22.3 To 24.2 lmol g–1. The courses of viscosity and carboxyl group contents were
- •Viscosity measurement additionally induces depolymerization due to strong
- •11 Pulp Properties and Applications
- •Increasing ozone charges. For more detailed
- •11.3 Dissolving Grade Pulp
- •Is more selective when ozonation represents the final stage according to an
- •11.3.2.3 Supramolecular Structure
- •1042 11 Pulp Properties and Applications
- •Is further altered by subsequent bleaching and purification processes. This
- •Involved in intra- and intermolecular hydrogen bonds. The softened state favors
- •11.3 Dissolving Grade Pulp
- •Interestingly, the resistance to mercerization, which refers to the concentration of
- •11 Pulp Properties and Applications
- •Illustrate that the difference in lye concentration between the two types of dissolving
- •Intensity (see Fig. 11.18: hw-phk high p-factor) clearly changes the supramolecular
- •11.3 Dissolving Grade Pulp
- •Viscose filterability, thus indicating an improved reactivity.
- •11 Pulp Properties and Applications
- •Impairs the accessibility of the acetylation agent. When subjecting a low-grade dissolving
- •Identification of the cell wall layers is possible by the preferred orientation of
- •Viscose pulp (low p-factor) (Fig. 11.21b, top). Apparently, the type of pulp – as well
- •11 Pulp Properties and Applications
- •150 °C for 2 h, more than 70% of a xylan, which was added to the cooking liquor
- •20% In the case of alkali concentrations up to 50 g l–1 [67]. Xylan redeposition has
- •11.3 Dissolving Grade Pulp
- •Xylan added linters cooked without xylan linters cooked with xylan
- •Viscosity
- •In the surface layer than in the inner fiber wall. This is in agreement with
- •11 Pulp Properties and Applications
- •Xylan content in peelings [wt%]
- •Xylan content located in the outermost layers of the beech phk fibers suggests
- •11.3.2.5 Fiber Morphology
- •11 Pulp Properties and Applications
- •50 And 90%. Moreover, bleachability of the screened pulps from which the wood
- •11.3.2.6 Pore Structure, Accessibility
- •11.3 Dissolving Grade Pulp
- •Volume (Vp), wrv and specific pore surface (Op) were seen between acid sulfite
- •11 Pulp Properties and Applications
- •Irreversible loss of fiber swelling occurs; indeed, Maloney and Paulapuro reported
- •In microcrystalline areas as the main reason for hornification [85]. The effect of
- •105 °C, thermal degradation proceeds in parallel with hornification, as shown in
- •Increased, particularly at temperatures above 105 °c. The increase in carbonyl
- •In pore volume is clearly illustrated in Fig. 11.28.
- •11.3 Dissolving Grade Pulp
- •Viscosity
- •11 Pulp Properties and Applications
- •Increase in the yellowness coefficient, haze, and the amount of undissolved particles.
- •11.3.2.7 Degradation of Dissolving Pulps
- •In mwd. A comprehensive description of all relevant cellulose degradation processes
- •Is reviewed in Ref. [4]. The different modes of cellulose degradation comprise
- •11.3 Dissolving Grade Pulp
- •50 °C, is illustrated graphically in Fig. 11.29.
- •11 Pulp Properties and Applications
- •In the crystalline regions.
- •11.3 Dissolving Grade Pulp
- •Important dissolving pulps, derived from hardwood, softwood and cotton linters
- •11.3 Dissolving Grade Pulp 1061
- •Xylan rel% ax/ec-pad 2.5 3.5 1.3 1.0 3.2 0.4
- •Viscosity mL g–1 scan-cm 15:99 500 450 820 730 1500 2000
- •1062 11 Pulp Properties and Applications
- •Isbn: 3-527-30999-3
- •Introduction
- •Isbn: 3-527-30999-3
- •1072 1 Introduction
- •Isbn: 3-527-30999-3
- •Inventor of stone groundwood. Right: the second version
- •1074 2 A Short History of Mechanical Pulping
- •In refining, the thinnings (diameter 7–10cm) can also be processed.
- •In mechanical pulping as it causes foam; the situation is especially
- •In mechanical pulping, those fibers that are responsible for strength properties
- •Isbn: 3-527-30999-3
- •In mechanical pulping, the wood should have a high moisture content, and the
- •In the paper and reduced paper quality. The higher the quality of the paper, the
- •1076 3 Raw Materials for Mechanical Pulp
- •1, Transversal resistance; 2, Longitudinal resistance; 3, Tanning limit.
- •3.2 Processing of Wood 1077
- •In the industrial situation in order to avoid problems of pollution and also
- •1078 3 Raw Materials for Mechanical Pulp
- •2, Grinder pit; 3, weir; 4, shower water pipe;
- •5, Wood magazine; 6, finger plate; 7, pulp stone
- •Isbn: 3-527-30999-3
- •4.1.2.1 Softening of the Fibers
- •1080 4 Mechanical Pulping Processes
- •235 °C, whereas according to Styan and Bramshall [4] the softening temperatures
- •Isolated lignin, the softening takes place at 80–90 °c, and additional water
- •4.1 Grinding Processes 1081
- •1082 4 Mechanical Pulping Processes
- •1, Cool wood; 2, strongly heated wood layer; 3, actual grinding
- •4.1.2.2 Defibration (Deliberation) of Single Fibers from the Fiber Compound
- •4 Mechanical Pulping Processes
- •Influence of Parameters on the Properties of Groundwood
- •In the mechanical defibration of wood by grinding, several process parameters
- •Improved by increasing both parameters – grinding pressure and pulp stone
- •In practice, the temperature of the pit pulp is used to control the grinding process,
- •In Fig. 4.8, while the grit material of the pulp stone estimates the microstructure
- •4 Mechanical Pulping Processes
- •4.1 Grinding Processes
- •Is of major importance for process control in grinding.
- •4 Mechanical Pulping Processes
- •4.1.4.2 Chain Grinders
- •Is fed continuously, as shown in Fig. 4.17.
- •Initial thickness of the
- •75 Mm thickness, is much thinner than that of a concrete pulp stone, much
- •4 Mechanical Pulping Processes
- •Include:
- •Increases; from the vapor–pressure relationship, the boiling temperature is seen
- •4 Mechanical Pulping Processes
- •In the pgw proves, and to prevent the colder seal waters from bleeding onto the
- •4.1 Grinding Processes
- •In pressure grinding, the grinder shower water temperature and flow are
- •70 °C, a hot loop is no longer used, and the grinding process is
- •4 Mechanical Pulping Processes
- •Very briefly at a high temperature and then refined at high
- •4.2 Refiner Processes
- •4 Mechanical Pulping Processes
- •Intensity caused by plate design and rotational speed.
- •4.2 Refiner Processes
- •1. Reduction of the chips sizes to units of matches.
- •2. Reduction of those “matches” to fibers.
- •3. Fibrillation of the deliberated fibers and fiber bundles.
- •1970S as result of the improved tmp technology. Because the key subprocess in
- •4 Mechanical Pulping Processes
- •Impregnation Preheating Cooking Yield
- •30%. Because of their anatomic structure, hardwoods are able to absorb more
- •Is at least 2 mWh t–1 o.D. Pulp for strongly fibrillated tmp and ctmp pulps from
- •4 Mechanical Pulping Processes
- •4.2 Refiner Processes
- •1500 R.P.M. (50 Hz) or 1800 r.P.M. (60 Hz); designed pressure 1.4 mPa
- •1500 R.P.M. (50 Hz) or 1800 r.P.M. (60 Hz); designed pressure 1.4 mPa;
- •4.2 Refiner Processes
- •4 Mechanical Pulping Processes
- •In hardwoods makes them more favorable than softwoods for this purpose. A
- •4.2 Refiner Processes
- •Isbn: 3-527-30999-3
- •1114 5 Processing of Mechanical Pulp and Reject Handling: Screening and Cleaning
- •5.2Machines and Aggregates for Screening and Cleaning 1115
- •In refiner mechanical pulping, there is virtually no such coarse material in the
- •1116 5 Processing of Mechanical Pulp and Reject Handling: Screening and Cleaning
- •5.2Machines and Aggregates for Screening and Cleaning
- •5 Processing of Mechanical Pulp and Reject Handling: Screening and Cleaning
- •5 Processing of Mechanical Pulp and Reject Handling: Screening and Cleaning
- •5.3 Reject Treatment and Heat Recovery
- •55% Iso and 65% iso. The intensity of the bark removal, the wood species,
- •Isbn: 3-527-30999-3
- •1124 6 Bleaching of Mechanical Pulp
- •Initially, the zinc hydroxide is filtered off and reprocessed to zinc dust. Then,
- •2000 Kg of technical-grade product is common. Typically, a small amount of a chelant
- •6.1 Bleaching with Dithionite 1125
- •Vary, but are normally ca. 10 kg t–1 or 1% on fiber. As the number of available
- •1126 6 Bleaching of Mechanical Pulp
- •6.2 Bleaching with Hydrogen Peroxide
- •70 °C, 2 h, amount of NaOh adjusted.
- •6.2 Bleaching with Hydrogen Peroxide
- •Is shown in Fig. 6.5, where silicate addition leads to a higher brightness and a
- •Volume (bulk). For most paper-grade applications, fiber volume should be low in
- •Valid and stiff fibers with a high volume are an advantage; however, this requires
- •1130 6 Bleaching of Mechanical Pulp
- •6.2 Bleaching with Hydrogen Peroxide
- •Very high brightness can be achieved with two-stage peroxide bleaching, although
- •In a first step. This excess must be activated with an addition of caustic soda. The
- •Volume of liquid to be recycled depends on the dilution and dewatering conditions
- •6 Bleaching of Mechanical Pulp
- •6 Bleaching of Mechanical Pulp
- •Is an essential requirement for bleaching effectiveness. Modern twin-wire presses
- •Is discharged to the effluent treatment plant. After the main bleaching stage, the
- •6.3 Technology of Mechanical Pulp Bleaching
- •1136 6 Bleaching of Mechanical Pulp
- •Isbn: 3-527-30999-3
- •7.3 Shows the fractional composition according to the McNett principle versus
- •1138 7 Latency and Properties of Mechanical Pulp
- •7.2 Properties of Mechanical Pulp 1139
- •Isbn: 3-527-30999-3
- •In 1950, about 50% of the global paper production was produced. This proportion
- •4.0% Worldwide; 4.2% for the cepi countries; and 4.8% for Germany.
- •1150 1 Introduction
- •1 Introduction
- •1 Introduction
- •Virgin fibers
- •74.4 % Mixed grades
- •Indonesia
- •Virgin fibers
- •Inhomogeneous sample Homogeneous sample
- •Variance of sampling Variance of measurement
- •1.Quartile
- •3.Quartile
- •Insoluble
- •Insoluble
- •Insoluble
- •Integral
- •In Newtonion liquid
- •Velocity
- •Increasing dp
- •2Α filter
- •0 Reaction time
- •Increasing interaction of probe and cellulose
- •Increasing hydrodynamic size
- •Vessel cell of beech
- •Initial elastic range
- •Internal flow
- •Intact structure
- •Viscosity 457
- •Isbn: 3-527-30999-3
- •1292 Index
- •Visbatch® pulp 354
- •Index 1293
- •1294 Index
- •Impregnation 153
- •Viscosity–extinction 433
- •Index 1295
- •1296 Index
- •Index 1297
- •Inhibitor 789
- •1298 Index
- •Index 1299
- •Impregnation liquor 290–293
- •1300 Index
- •Industries
- •Index 1301
- •1302 Index
- •Index 1303
- •Xylose 463
- •1304 Index
- •Index 1305
- •1306 Index
- •Index 1307
- •1308 Index
- •In conventional kraft cooking 232
- •Visbatch® pulp 358
- •Index 1309
- •In prehydrolysis-kraft process 351
- •Visbatch® cook 349–350
- •1310 Index
- •Index 1311
- •1312 Index
- •Viscosity 456
- •Index 1313
- •Viscosity 459
- •Interactions 327
- •1314 Index
- •Index 1315
- •Viscosity 459
- •1316 Index
- •Index 1317
- •Xylose 461
- •Index 1319
- •Visbatch® pulp 355
- •Impregnation 151–158
- •1320 Index
- •Index 1321
- •1322 Index
- •Xylan water prehydrolysis 333
- •Index 1323
- •1324 Index
- •Viscosity 459
- •Index 1325
- •Xylose 940
- •1326 Index
- •Index 1327
- •In selected kinetics model 228–229
- •4OMeGlcA 940
- •1328 Index
- •Index 1329
- •Intermediate molecule 164–165
- •1330 Index
- •Viscosity 456
- •Index 1331
- •1332 Index
- •Impregnation liquor 290–293
- •Index 1333
- •1334 Index
- •Index 1335
- •1336 Index
- •Impregnation 153
- •Index 1337
- •1338 Index
- •Viscose process 7
- •Index 1339
- •Volumetric reject ratio 590
- •1340 Index
- •Index 1341
- •1342 Index
- •Index 1343
- •1344 Index
- •Index 1345
- •Initiator 788
- •Xylose 463
- •1346 Index
- •Index 1347
- •Vessel 385
- •Index 1349
- •1350 Index
- •Xylan 834
- •1352 Index
Vessel cell of beech
Section of springwood spruce tracheid
Kraft pulp fibers of spruce
Section of summerwood fir fiber
____ ___ ________ _ ____ ___ ______ ___ ___
_____
*_ ____ _______)
+_______ _______ ________ +_)# __ _ __ _____ __ ____ __ ___ ____ __ ________
__ _ _________ __ _,_____ _,_______ ___ ________ __ ________ ___ ________
___ ___ __________ __ ____ ____ ___ ____ ____ _____ ____ ___ _____________
__ ____________ __ ______ __%_
___
___ +_" ______
7 ______ __ ____ _ ____ __ _ _______ ________ __ _ _____ __ __ __ ___ ______
_______ ________ ___ ______ __ _ ________ __ _ __ ".. _____ ___ ______ _____ ___
_____ __ ___ ____ ___ _________# __ _ __ ____,______ ___ _____ ___ ____ ______
_____ D_ _ __________ ______ ______ __ ___ __ _ _____ ________ ___ ______
__ ___ _______ _____ __________ ____ __ ________ __ ___ ______ __________
___ ____
____ _____ ______ ___ _____ ______ __ ____ __ __ ___ __ _____ __ ____
________ ___ ___ _____ ______ ___ _____ __ _____ _____ ___ __ _ !_:#_ 0_ ___ __
________ _ _____ __ ______ __ ___ ___ __ __ ____ _ _______ ___ ___
______ __________ _____ _ ___________ ________
____ __, ______ ___ _ ______ ___ _ _______ ________ _ _________ _____ _____
___
__" _
_ _ _
__" _____
-. __ __ */________
______ ______ __ 1_____ __ _______
_____ __ _
contour length
(_E_____ ______ __ 1_____ __ _____
__ _ projected length
___ F _,____ __ ______
__ __ _
_G_F _ _ ______ ______
__E_____ ______ _ "__ "..
'____ __ @________ __
____ _______ Average width
'___ __ _________ __
__ _ ____ Wall thickness
__%_ _ _____ ___ _____
___ _____ __________
___
__" _
_ _ _
__" _____
-. __ __ */________
_____
_________ ___
__& ____ _______ ___
__ __ _ ____ Cross section area
D_ _ ______ __: _____ ______ __
_______ __ _
Fiber volume
_________ _ _>" )___ __ ____
______
Mass
per slice
Coarseness:
Mass per unit length
1 m
_____
___ 0 ____ 1___2 ___ 3____
_______ _________ _ _____ ___ _"__ -___)___
7 ____________ __ __ __________ __ _ _______ __ __ ______ ___ __________
______ __ ____ __ _ __ _ __________ _______ ____ ___ _ ____ ________ ________
____ __E______ ___ __________ _____ __ _ _____ ___ ________ ___ _______
__ __ __ _____ _ _____ ___ A"&&B_ 7___________ _____ _______ __ _ _____
3_____ _______ _______ _________ ___ __________ __ __ __ ____ __ _________
__ ____ _______ ______ _ ________ _____ ___ __ __ __ _________ __ ___ ____
_________ ___ ______ __ __________ __ __ _____ _ _____ __ _________
____________ _____ ________ __ ____________ ______ __ __ ___ _____ _ _____
_____ ________ _____ __ _ ________ _____ _______ ___ ___ _________ __ _
________ ____ _________ __ _____ __ _ _7((0 _______ ______ A"&:B_ 7_____
________ ________ __ _______ ___ ________ ___ ___ ___ __ _ _______ __ _ _______
_ _____ __ D_ _ ______ __ ____ __________ _____ ___ _________ ____ ___ ____
________
_____ _________ _________ ____ __ ___ H6_E____ __ _ ______I_ HD_ _ ____
__I _________ +_D0#_ _ ___ H(___ _,___I __ ______ ___ _____ __________
______ __________ _ ___ __ _ ______ _____ ______ ___ ______ __ _ _______ ___
___ __ _ _________ __ _ _______ D_ ________ _________ ________ _______ __
____ _________$ __ _,______ __ ___ ____ __ __ _ ______ ___ _______________
______ __ ___ _______
__%,
____ __, ___ _____
_ _____ ___ _____
)__ _____ __________ _____ HD_ ___ I$ )____ 7_________$ H6_E____ D+_
&..I# ____ ______ __________ __________ _ ___ __ _ _____ ___ __ _ ____ ______
_____ 0_ _________ _____ ________ ____ __ _____ ___ __ _ ___ __ _ _______
____ ____ _____ ________ @_______ ___ _______ __ ____ __ ____________ ___
________ __ _ __ __ ____ ___ ____ _____ ____ ____, ____ ____ _______ __ __ __ _
!_:_
_______ ___ ____________ _) __ ____
J_____________ ___ __ _ ______ _____ _____ __ _ ____ ___ ___ _____ _______ ___ _
_________ ________ ___________ ________ ______ ______ __ _________ ____
_____ D_ __ __ _______ ___________ ________ __ ____ ________ ________ ____
__ _ __________ ___ __ _ ___,_ ____ ____ ______ ___ ____________ ______ ___ _____
_______ __ _______ __ ___ _______ ____ ______ ______ ___ _____ ____ ________
_____ 7 ______ _,_____ __ ____ _________ __ ___ 8____)_9___ _________ _____
________ __ _ _____ __ _____ ____ ______ __ ________ ______ D___ !_&#_
fines
Prescreen 0.15 mm
chives
Fiber suspension
Screen # 6
Screen # 12
Screen # 20
Screen # 40
R 6
R 12
R 20
R 40
D 6
____ ___ ____ ___ ___ __ ________ _ _____ !_"_ _
______ _____ _____ ____ __ __________ ____ __ :._ !._ ".._ ___ &.. _____
)______ _______ ___ &.. ____ __ _____ _________ __ ______ _____ ____ __ __ __
___ _______ _______ __ ___ :._____ ______ 7 ______ _______ E_ @@K# ____ _
&.._____ ___ _____ ___ ____ _ ____ __ ______ ___ _____ _______ A"&=B_
__%4
___ __________ ___ _____
_____
____ _ __ 1___2
_________ __ _ ______ __ ___ ____ __ _ _____ __ __ _ ____________ __ _ ______
__________ ___ __ _____ __ ___ ______ __ " _ __ __ __ *_____ ___ _____ __ ______
____ __ ____ __ ____ _______ _________ ___ _ __________ ___ ___ ___ _ __
__ ___ ____ ______ _______ ___ ___ _____ _ ______ __ ___ __ __ __ _ _______ 7__
______ __ _ _______ ______ _____ __________ __ __________ ___ __________
____ ____ ___ _____ _ ______ __ ___ __ __ __ ___ ______ __ _____ _,_____
__,
_ ________ __ __ _
_____
_____ ___ __ __ _
D_ __ __ ______ ________ __ ___ ___ ______ ___ __ ________ __,____ ______
____ _____ ________ ___ _______ ___ ___ __ _ ________ __ _________ 0_ _
__ ___ _______ _ __ _ ________ ___ ___ ____ __ ___ ______L_ _________
_______ 3 _ ___ __ __ _
___ _________ _______ __ __ __ __ _ ______ ___________ _______# ______ __
________ ___ ________ ________ __ ___ _______ __ __$ _____ _______ ________ _____
___,_ _____ ___ _______ _____ _____ ____ __ __________ ____________ __ D___ !_:_
_______ ____ __ _ ___ ____ _____ _____ __ ___ _______ _________ 0______
__________ _ ___ _______ ____ ___ _ _______ ___ _ ___ _______ __ ________
____ ________#_ ___,_ ____ ___ ________ ____ ____________
________ ____ D__,_ ____ _______ ____
fiber cross
section
____ __, #_____ ___ _ ________ $ _ _____ __ _____
8 _______ ______ _______ ___ __ _ __ ________ ___ ______ ___ __ _ _______
____ _ ___ ________ _____ ___ __________ ____ ______ ___ _ _______ ______
_____ _ ___________ ______ __________ _____ ______ __ ________ ___ __ _ _______
__ __ ___ ____ __ ?. __ !.. 9 _>" __ _____ ______ ___ _______ ____ ___ _____
__ ________ __________ ______ __ 9___ _____ __ ______ __ __ _ !_=_
__%_
_ _____ ___ _____
____ __4 __________ _____ %_ !&_' __ __
"____$ ______ ____ (__)*_
____ #___ _5"" #___
+______ ____ "..>"&. "!.>&..
6___ ____ &!.>:.. :..>=..
D__,_ ____ _ ___ ______ _________ __ ____ _____ ________ ___ ________ __ ______
____ __ _ _________ ___ __ _ ___ ________ ____ ____ ___ _____________ 3_____
_______ ___ ___ _________ ________ ______ _ ______ __ _ __ _______ ___ ___
____ ____ ___ ____ ___ ________ ____ ____ ___ ________ ____ __ 7 ______
____ __ _______ _ __________ ____ _______ _ ____________ _ _______
______ ___ ___ __________ __ ___ __ _ __ ________ 7_______ __ +________ __ __
__ __________ ___ _ _____ _____ __ _ _____ ______ 8 _______ _________
_______ _ __ _ __ _______ ______ _______ ___ _____ ______ ______ _ _______ __ ___
__ _ ____ ___ _____ __ __ __ __ _______ ___ ____ ___ ___ ___,_ __ ___ __ __ ___
___ __ ____ ___ _____ ___ ___ _______ _______ __ _ ______ ___ __ ___________
D___ !_=#_
hydrostatic pressure
glass plate
wire
fiber
flow
fiber
a) b)
____ __4 #_______ _ ________ _____ ___ _____ $_
________ __ +_______ ________ __ ___ @_ ___ 6____
___ ____ ____ __ ______ ______ __ _ ____ _________ ___ @_ ___ 6_____
A"&;B_ 7_______ __ ____ _______ _ __ _ __ __________ _________ ___ _ _____
_______ _________ '___ _ _____ __ ____ __ ______ ______ ___ _____ ___ __ _
_____ D__ ___ _________ ____ ___ _______ __ ___ __ __ ___ _________ __
__%_
___ __________ ___ _____
_ ________ +________ __ _____ __ ____ _____ ____ __ _______ ______ ___ ________
____ _________ _____ __ _______________ A"&?B_ 4_______ _____ ____ __ __ __
____,______ _____ __ ___,_ __ __ _____ ____ __ ___ ___ ___ ___,_ ____
________ ______ ____ _____ __ ______ +_______M_____# A"&<B_
_______ _ ________ __ __ _ __ +) ___ _
___ ______ __ _ ____ __ _____ ___ ______ ____ __ ______ __ __ ___ ______
___ _____ __ __ _____ *____ __________ ____ __ _ _______ ___ ___ _____>
_____ ______________ __ _____ __ D___ !_!_ '___ __________ _____ __ _______ __ _
___ __ ____ ____ __ ____ _____ __ _ ______ _____ _______ _______ _____#_
8 ________ ___ ___ ___ _______ _______ __ ____ ________ ________ ___
______ _____ 0_ _________ __ ___ ___ ________ _______ __ ___ ____ _______
___ _______ __ _____ ___ ___ _ _________ ________ _____________ 7_
____ _________ ___ ___ _____ _______ __________ ________ +___ ____ ______
________ _______ ______ __ _________ _______ _____ ________ __ ___ _________ _____
_________ ___ ________ __ _______ ______ _____ ________ _____ __ ___ _________
___ ____ __________ _______ H________I _______#_ _____ ____# ___ ___
______ ___ __ _ __ ___ _______________ _________ __________ ________#_ 7__
____ ______ ____ ___ _______ __ _________ ___ ______ _____ ___ __ ______
____ _______ ______ ___________
D_ ___ ______________ __ _____ ___ _____ ___ ____ _______ _______ ___ __
__________ __ ___________ 7 ___ _,_______ _______ ___ _______ __ ___________
___ ______ ____ ___ ______ __ ____ ___ _______ ____, __ ______ ___ ___ ____
___ _____ _____ __ ___ _______ __ ___ __________ __ ___ _______