Chapter 1

Introduction

1.1 General

Refining refers to the mechanical treatment of chemical pulp in preparation for papermaking. It is an important process for improving pulp properties. In the process of refining, fibers are trapped in the gaps between bars during bar crossings where they are subjected to cyclic compression and shear forces which modify the fiber properties. [Heymer, 2002]. The main target of refining is to modify surface characteristics as well as fiber flexibility in order to develop stronger and smoother paper with good printing properties,. In addition, sometimes the purpose is to develop other pulp properties such as absorbency, porosity, or visual appearance. [Yan Li, 2005].

Low Consistency (LC) refining at 3-5% has many benefits because the pulp suspension acts as an incompressible fluid and therefore may be pumped through the refiner using an external pump. This mixture is more homogeneous than pulp at high consistency (30%) and consequently the refining treatment more uniform. This is evident in the smaller, more uniform gap between the plates, and more stable refiner power consumption. Another benefit of LC refining, related to the above, is that the intensity of treatment and pulp throughput are decoupled, allowing them to be independently controlled and optimized. [Luukkonen, 2011]

The possibility of having an optimum condition for refining intensity arises from the fact that low intensity refining imposes gentle refining effect, thus flexibilizing fibers through internal fibrillation without further disrupting the fiber structure, while on the other hand, high intensity disrupts the fiber structure harshly and creates fibre shortening. However, the literature on an optimum intensity is inconclusive and occasionally contradictory. .Nazhad et al (2001) studied the effect of refining of chemical pulp on paper formation. The authors concluded that fiber shortening caused by refining had strong effect on reducing fiber flocculation, thus improving formation. The author also discussed the fact that the optimum refining intensity should vary depending on raw material properties.

The refining process is usually described by two factors, refining intensity and refining amount. The amount of refining is represented by specific energy. The intensity is represented in different ways. One approach is by a “machine intensity” (Kerekes 2010). The most used parameters for this is Specific Edge Load (SEL) (Baker 1995). Modifications of the specific edge load have been suggested, for example the Modified Edge Load (MEL) by (Melzer 1995), Specific Surface Load (Lumiainen 1995). Even more complex expressions were developed by (Joris 1995) (Radoslava, Roux et al. 1997)]. Another approach to characterizing intensity is by a “fibre intensity ”. This is based on energy expended on fibre rather than by bar crossings as is the case for machine intensities. An example is the C-factor (Kerekes 1990) which takes into account the properties of the fiber suspension. However, apart from the SEL, none of the other methods have gained wide acceptance.

Of the simpler models, Lumiainen (1994) studied the refining intensity on the hardwood pulp. He concluded that the lower the intensity is better for fiber development and gives lower the energy consumption. Kerekes (2010) compared tensile strength increase for hardwoods and softwoods using both the SEL and the Specific Intensity from the C-Factor. He showed that the that SEL had limitations, but for Specific Intensity the data for both hardwood and softwood fell on one line, and that the optimum SEL’s for each occurred at the same Specific Intensity. Eileen Joy and Desaeada (2010) concluded the ultra-low intensity refining plate would have benefits for hardwood chemical pulps because gentle refining action increased the specific surface area of the fibers by internal fibrillation, leading to greater strength development. On the other hand, Soupajarviel at, (2009) reported higher refining intensity results fiber fibrillation (external) while fiber length remained unchanged by using high intensity dispergator with LC refining.

Koskenhely et al, 2005 compared the fillings in refining of softwood and hardwood pulp fibers. Their results showed a better dewatering-tensile strength combination when SW was refined with conical fillings. Also, the reduction in fiber length was inversely proportional to gap size because fibers are squeezed and crushed between the bars.

Some work suggested that the refiner gap would be better indication of the ‘effective refining intensity’ than the conventional Specific Edge Load (SEL) and that the power – gap relationship governs the refining result [Luukkonen, 2011]. Moreover, changes in fiber length and fiber curl were also controlled by plate gap and can be related to water retention value (WRV) better than energy and power in refining of chemical pulp. [Mohlin, 2002].

1.2 Objectives of the research

The overall objective of this research is to determine optimum conditions for refining Northern Bleached Softwood Kraft (NBSK) pulp ensure that Canadian pulp customers are optimally refining their pulp. The objective is divided into three parts, which are:

1. To compare gap size and SEL for characterizing the refining intensity.

2. To study the effect of refining intensity on internal fibrillation (tensile, tear, water retention value) and fibre cutting.

3. To determine the optimal refining conditions for chemical pulps in terms of maximum tensile strength at a given specific energy.

1.3 Scope of Study

The scope of this experiment is limited to the pilot scale refiner to achieve the above objectives. These studies focused on chemical pulp (bleached Softwood Kraft pulp).

Chapter 2

Literature Review

2.1 Refining mechanism

The refining mechanism is based on the following picture. It is assumed that the fibers are captured in the form of fiber flocs and that the effective refining action starts when the fiber bundle is pressed between the leading edges—the edge-to-edge phase in Figure 2.1. This phase is followed by and edge-to-edge surface phase, which continues until the leading edges reach the tailing edges of the opposite bars. The length and the strength of the fiber flocs depend on the physical dimensions and the bonding ability of various fibers in the mixture.

Figure 2.1: Refining mechanism (Paulapuro et al., 2000)

2.2 Refining theories

The utilization of new theories, since 1967, has enabled a better understanding of what happens inside the refiner, and allowed better means for optimization. Fundamental to all the theories is the understanding that the refining result is a function of two major factors, among others:

· The amount of applied energy

· How is the energy applied

More rigorously, the refining process is a cyclic application of energy to pulp, and therefore it can be described in terms of number and intensity of impacts on fibres. The product of these equals specific energy. Only two of these parameters are independent. It is common to only use specific energy and intensity.

The most commonly used intensity is the Specific Edge Load (SEL).This machine intensity has provided a significant contribution in the search for an index representing the intensity of the beating performance, describing the beating absorption by a pulp, at least with respect to its nature. Although developed empirically, it has been shown by Kerekes & Senger (2006) to have a rigorous scientific meaning: its is the energy expended per bar crossing per bar length. This concept has been developed into other refining theories, all involving the character of the beating action as described by the type (or intensity) of refining, and the extent of action, which is related to the amount of refining imposed on the fiber flocs.

The goal of refining theory is to predict changes in pulp properties from known refining conditions and to allow for the comparison of different refining plates, or fillings, under various operating conditions. There are currently seven main refining theories as shown below:

2.2.1 Specific Edge Load Theory

The specific edge load theory is the most commonly used and simple theory in practice today. The characterization of the refining process is given by the specific energy, E (kW*hr/ton), and the refining intensity parameter, specific edge load (SEL). The SEL is a measure of the energy expended per bar crossing per bar length, having unit of J/m. Its is obtained form equation 2.1.

Eq. 2.1

PNET is the net input power (W). The cutting edge length, CEL (m/s), is the product of the plate factor, Kp (m/rev) and the angular velocity,(rev/s). Kp is the sum of the product of the number of bars on the rotor, Zr, the number of the bars on the stator, Zs, and the length of a bar, L(m), over increments, i, in the refining zone.

2.2.2 Modified Edge Load Theory

The modified edge load theory is an extension of the specific edge load theory that takes into account additional filling parameters. The characterization of the refining process is given by E and the refining intensity parameter, modified edge load (MEL), see Equation 2.2:

Eq. 2.2

is the average bar angle (the angle between the bar and a radial line drawn through the center of the bar section in degrees), B is the bar width (m) and G is the groove width (m). Note that the modified edge load theory is an empirically derived theory which accounts for both operating conditions and filling parameters.

It should be noted that the benefit of the MEL theory is that it allows refining results to be forecast as a function of freeness at a constant refining intensity is not considered in this project. The trend of strength development as a function of refining intensity will be the focus of this analysis.

2.2.3 Specific Surface Load Theory

The specific surface load theory is another extension of the SEL theory that accounts for additional filling parameters. The refining process is characterized by E and the refining intensity parameter, specific surface load (SSL). The SSL may be thought of as a measure of the energy expended per area of bar crossing as its units is J/m2, see Equation 2.3:

Eq. 2.3

Wr is the width of the rotor bars (m), Ws is the width of the stator bars (m) and α is the cutting angle (degrees), defined as twice. As with the previous two theories, the specific surface load theory is an empirically derived theory which accounts for both operating conditions and filling parameters.

2.2.4 C-Factor Theory

The C-Factor theory characterizes the refining process by the refining intensity parameter, I, and the number of impacts N. These parameters are related to E, PNET, the C-Factor (C), and the fiber mass flow rate (F) as indicated in Equations 2.4 through 2.6:

Eq. 2.4

Eq. 2.5

Eq. 2.6

The C-Factor represents the capacity of refiner to inflict impacts on fibers passing through it (impacts/s). Note that the C-Factor theory, unlike the other theories considered so far, is derived from fundamental principles. It accounts for the operating conditions and the filling parameters, as well as the fiber properties. Equation 2.7 gives C for a disc refiner with a small gap and the same bar pattern on the rotor and stator.

Eq. 2.7

D is the groove depth (m), is the density of the pulp suspension (kg/m2), CF is the consistency of the pulp suspension (fraction), l is the length-weighted average fiber length (m), n is the bar density or bars per unit arc length (m-1), R2 is the outer radius of the refining zone (m), R1 is the inner radius of the refining zone (m), and w is the fiber coarseness (kg/m).

Senger (1990) observed that the bar density is not constant across the entire length of the refining zone due to changes in the bar pattern or large values of bar angle. To alleviate this impact on the C-Factor, C may be derived in terms of the plate factor, see Equation 2.8:

Eq. 2.8

Equation 2.9 may be used for either disc refiners. The refining process will be characterized by the C –Factor theory using E and I.

2.3 Refining chemical pulp

Refining increases ability of fibre to hold water by causing swelling as a result of delaminating the cell wall. This increases flexibility. Swelling is an indicator of the amount of delamination. However, swelling and fines retard the drainage of water from the pulp thus lowering the drainage rate on the former and making it harder to press and dry the wet-web.

The effect of refining on paper properties will depend upon the severity of the mechanical treatment. Two terms that are used are “cutting” and “brushing”. Cutting refers to shortening the fiber length of the stock by mechanical action, while brushing refers to internal and external fibrillation and opening up the secondary wall of the fiber by stock hydration and increasing the surface area of the pulp. If cutting predominates, the paper will be soft, bulky, flexible, and dimensionally stable. By contrast, if brushing predominates, the paper will be strong and stiff. (Genco J.M, 1999)

2.4 Effect of Refining on Fiber Morphology

Wood fibers are the structure material of paper. In order to understand the effects of refining on paper properties the effects of refining on fiber must be clarified. Wood fiber is made up of four parts: (W) tubercular core (lumen), (S1,2,3) secondary wall, (P) primary wall and (M) intermediate lamella (Figure 2.2). (Marko Loijas, 2010)

Figure 2.2 Structure of Nordic softwood tracheids (Marko Loijas, 2010)

The chemical composition of these layers is primary cellulose, hemicelluloses and lignin. The cellulose and the hemicelluloses molecules are able to form hydrogen bonds with the adjacent molecules. The fibers of paper are bonded to each other by hydrogen bonds, thus giving the fiber network its strength. Removal of the primary wall and S1 layer can be improves strength properties of paper. (Marko Loijas, 2010)

The main effects of refining on pulp are internal fibrillation, external fibrillation, creation of fines and shortening of fibers. The details of these effects are described below.

2.4.1 Internal Fibrillation

The refining chemical pulp increases fiber flexibility because of internal fibrillation. This occurs from delaminating in the cell wall. Water is drawn into the fiber walls by capillary forces, causing swelling which is often used as an indicator of degree of refining. The weakened cell wall is more flexible and collapsible, thereby giving a larger relative bonded area in paper. This in turn increases bonding and thereby paper strength.

2.4.2 External Fibrillation

External fibrillation is the delamination of fiber surfaces. This can be defined as a peeling off of fibrils from the fiber surface, while leaving them attached to the fiber surface. It is emphasized that the fiber surface can be fibrillated even in the early beating stage, and that the external fibrils serve as bonding agents for inter-fiber bonding. The amount of such fibrillation (parts of fiber wall still attached to fiber) can be quantified by measuring the increase in the specific surface of the long fiber fraction

2.4.3 Creation of fines

Fines are produced in refining as a result of fiber shortening or removal of fibrils from fiber walls. Generated fines consist mostly of fragments of P1 and S1 layers of the fiber wall due to the abrasion of fibers against each other or against refiner bars. Fines, meaning loose fibrous material of size less than 0.3 mm, are produced in refining

2.4.4 Shortening of fibers

Refining causes fiber shortening which is generally undesirable in refining. Fiber cutting which reduce average fiber length and affect paper properties that are related to fiber length, formation and strength. [Nazhad el at, 2001] In some rare applications it is a desired effect to improve formation by decreasing the crowding number. (Kerekes, 1995, Nazhad el at. 2001)

2.5 Effect of Refining on Sheet Properties

Refining affects virtually all important sheet properties. Some properties are improved while others are diminished , so the papermaker is always making judgments as to how much refining to do. Properties such as paper formation, tensile, burst, fold, smoothness, density, air resistance, and stiffness are improved, while the pulp drainage rate, porosity, tear (mainly for softwoods), bulk, caliper, and dimensional stability are decreased. The sheet will have a greater tendency to curl and have a cockled appearance with increased refining. Also, coating holdout will increase. Thus, the degree of refining is an important wet end operation that the papermaker must control.

The effect of refining on the properties of the final sheet can be classified into three groups: (i) strength properties, (ii) sheet formation, and (iii) density-related properties.

2.5.1 Strength properties.

The properties of tensile, burst, and fold strength are improved by refining up to a maximum. These improvements may be attributed to the increase in the Relative Bonded Area (RBA) among fibres in paper, due to fibre flexibility and external fibrillation. The increase of these two fiber properties promotes inter-fiber bonding, which promotes additional hydrogen bonding between the hydroxyl groups on the cellulose molecules making up the fibrils. Beyond the maximum, there is no change or a reduction in tensile, burst and folding strengths. Using burst strength as an example eastern, western, and southern softwood kraft pulps will all respond to refining differently because of intrinsic morphological differences and small changes in the chemical composition of the pulp. General classification is difficult due to the many types of pulp available. Thus, each pulp needs to be tested individually. Additionally, there is considerable variation in the pulp due to the day-to-day operation of the pulp mill.

An exception to the aforementioned behavior is the tear strength. The primary effect of refining on softwood pulps is an initial increase in tear strength, followed by a continuous reduction of tearing strength with an increasing degree of refining. For hardwood pulps, there is a small increase and then little change in tear with refining. The tear strength of pulps is strongly dependent upon the fiber length of the pulp. (Genco J.M, 1999)

2.5.2 Sheet Formation.

The uniformity of fiber distribution in a formed sheet can be improved by refining. This is because sheet formation is controlled primarily by fiber length; long fibers make it more difficult to achieve good formation. It should be noted that the maximum strength of a sheet is attainable only when the sheet has good formation.

2.5.3 Density related properties.

The sheet density increases with refining since it is controlled by fiber flexibility and stock hydration; more flexible fibers can form a denser sheet. It has been used as a measure of the extent of refining. Density-related properties such as the bulk (bulk=1/density), porosity, opacity and dimensional stability are all reduced by refining.

Chapter 3

Methodology

3.1 Materials

3.1.1 Pulp

A market softwood bleached kraft pulp from Canfor pulp mill was used in the study. This softwood is a blend of white spruce (Piceaglauca), lodgepole pine (Pinuscontorta) and alpine fir (Abieslasiocarpa). This raw material was produced by using kraft pulping process and modern bleaching and screening systems. Bleaching is done with chlorine dioxide, oxygen and hydrogen peroxide resulting in environmentally superior enhanced ECF pulps. Length of average fiber is 2.4 – 2.6 mm.

3.1.3 Equipment

The Low Consistency (LC) refining facility consists of a 16 inch LC refiner, 150HP variable speed motor, gap sensor and with a wide range of FineBar refiner plate patterns. The refiner is fed by 2, 4 m3 tanks and a 40kW variable speed pump. It is instrumented with flow, pressure and temperature and has actuated valves which are computer controlled. The 150 HP, 1800 RPM motor allows a wide range of refining power at different speeds.

Figure 3.1 The UBC – PPC Low consistency refiner and refining facility

3.2 Experimental Procedure

This experiment focused on studying the effect of refining intensity on fiber properties. The properties of the pulp were measured before refining. Properties measured were freeness, fiber length, paper strength (tensile, tear, density) and water retention value (WRV). The pulp was refined in the pilot LC refiner at 3.5% consistency and constant flow rate. The refining temperature was 20-25 ºC. The refining parameters studied were refining plate geometries, refining speed and bar gap. These measurements were done in order to quantify the refining intensity.

Plate patterns studied were various bar width, groove width and groove depth as well as bar angle. The refining speed was 1000, 1200 and 1400 rpm, respectively. Refining conditions are given in table 3.1 and 3.2. Specific energy and intensity were calculated using measured data in each condition.

Table 3.1 Summary of the parameters studied in this experiment.

Parameters

Condition

Consistency

3.5%

Plate geometrics

Two

Refiner speed

1000, 1200, 1400 rpm

Flow rates

200 l/min

Gap

Fives

Table 3.2 Refining plate geometries.

No.

# BarWidth

[mm]

GrooveWidth

[mm]

GrooveDepth

[mm]

Angle

[°]

BEL

[km/rev]

1

1.6

3.2

4.8

15

2.74

2

2.0

3.6

4.8

15

2.01

Pilot low consistency (LC) refiner is a part of UBC flow loop system in figure 3.1. The flow loop consists of two tanks, a centrifugal pump, and a single 16” disc LC refiner. Pulp injected to LC refiner from a tank and the output ended up in the second tank. This refiner equipped with magnetic flow meters, pressure sensors, temperature sensors, power meters, plate position and it is controlled by actuated valves, plate actuation and variable speed drives on the pump as well as refiner. The refiner is operated and data collected using a LABVIEW™ interface. The procedure to operate LC refiner are as follows:

1. The procedure was started by changing the refiner plate, then pulps were prepared at 3.5% consistency in tank A and mixed for 4 h.

2. To adjust flow rate, the circulation loop of the LC refiner was started. The refiner speed was adjusted as well, then the refiner gap was changed from 9.0 to 2.5 mm to measure no-load power.

3. After system recirculation and recording of no- load power, refining process was started by feeding pulp from tank A to the LC refiner, then collecting it at tank B after refining. Refiner gap was changed in the process, and the samples were also collected for further analysis.

4. Refiner speed and refiner plate were changed when the new condition applied.

(TankATankBSample valvePumpLC refinerLabView)

Figure 3.2 Illustration of the UBC pilot LC refiner loop system used for these trials.

Refined fibers from each condition were characterized in terms of freeness and fiber length. For fiber strength development, handsheets from refined pulp were formed and tensile strength, tear strength and density were measured.

Canadian Standard Freeness (CSF) [ml] is a measure of the volume of water collected from a pulp suspension drained from one exit-nozzle in a specialized dewatering cell. The standard procedure of measuring pulp drainage is laid out in standard TAPPI T227.

The tensile index [Nm/g] is the ratio of the tensile strength per unit width [N/m] of a paper sheet to its basis weight [g/m2]. The tensile index is a measure of the ultimate strength of paper. It is normalized to its areal density, opposed to its thickness, as the thickness of the paper is highly variable. In this case, the roughness elements of paper are the same order of magnitude as its average thickness. The standard method for this measurement is explained in TAPPI T494.

Tear index [mNm2/g] is calculated similarly to the tensile index by dividing the measured tear strength [mN] of the paper sheet normalized by its basis weight [g/m2], TAPPI standard T414. Higher paper tear strength indicates greater resistant to the propagation of a tear.

Density [g/cm3] calculated from caliper, i.e. thickness [mm], and basis weight [g/m2], TAPPI standard T500. Paper density is related to the resulting paper quality, and higher bulk is desired for absorbent papers.

Fiber length is determined by measuring the length of a large number of individual fiber and then averaging the values either as the arithmetic average fiber length. These measurements use a Fiber Quality Analyzer (FQA).

Water retention value (WRV) test is water into lumens of fibre that provides the ability of fibre to take up water and swell. The WRV value equals the ratio of the water mass to the dry mass. The test is carried out by placing a pad of moist fibers in a centrifuge tube that has a fritted glass filter at its base. The centrifuge is accelerated at 900g to remove water from the outside surfaces and lumens of the fiber (a higher force is used according to some European standards). The remaining water is believed to be associated with submicroscopic pores within the cell wall. The centrifuged fiber pad is weighed, dried at 105 degrees Centigrade, and then reweighed.

(Raw material preparation(Measure the initial properties: Freeness, Fiber length, tensile index, tear index and density))

(Refining (Constant: consistency, temperature, flow rate, plate)(Variable: refiner speed and Gap))

(CharacterizingPulp properties: (Freeness (CSF), fiber length)(Make handseets from refined pulp: tensile index, tear index and density)Refining energy: Specific refining energy (SRE), refining intensity)

(Analyzing(Gap-power, critical gap on fibre cutting and strength properties))

Figure 3.3 Experiment chats

15

Figure 3.4 Design of experiment

26

Chapter 4

Result and Discussions

4.1 Refiner performance (Power-Gap relationship)

Refiner performance is commonly characterized by the specific energy and intensity. Both are affected by the power input to the refiner. This power is controlled by actuating the plate position to change the gap between the plates. Power increases when the plate gap is decreased as show in the figure 4.1. The power increases due to fiber trapping on the bar edge when we close the gap and it requires more power to compress and shear the fiber network (Bachelor et al, 2006).The interaction of fiber and rapidly rotating bars create a complex relationship between the operating conditions, design variables of the refiner and the resulting pulp quality (Olson el, 2012).

Figure 4.1 shows the relationship between power and gap clearance. The trends of the curves suggest that high refining speed requires high power consumption..

Figure 4.1 Relationship between total power and gap clearance at low consistency refining for bleached softwood kraft pulp

As the above figure shows the no-load power at gap clearance of 2.5 mm is quite different from plate to plate, but the dominating factor is the refiner speed. The no-load power of plates 2.74 and 2.01 are approximately 16.33 and 15.90 kW at1000 rpm, but it increases to 26.64 and 25.11 kW or 42.18 and 34.72 with incremental increase of 200 rpm in refining speed. The no-load power of high refiner speed is higher because the refiner uses the motor to drive rotor plate of refiner, so the high rotation speed of refiner needs more power to operate the motor.

Figure 4.2 Relationship between net power and gap clearance at low consistency refining for bleached softwood kraft pulp

Although some works have suggested a possible relationship between power and gap clearance, yet there is no theory to define the relationship between power and gap clearance, even though it is very important for understanding the refining function, Gap clearance controls power, energy as well as intensity in refining. Batchelor and Lundin (2006) used exponential function to explain the relationship between power and gap clearance. Our observation (Figure 4.2) supports finding of Batchelor and Lundin (2006) where the refiner net power was consumed as a function of the refining gap between the rotor and stator bars, however, the relation could not be used for estimating the refining intensity.Figure 4.3 Relationship between net power and inverse of gap clearance for low consistency refining of bleached softwood kraft pulp

Figure 4.3 well demonstrates the relationship between plate gap power. Decrease in plate gap suggests increase in power. Work of Mohlin (2007) and Luukkonen (2010) have also shown that power is inversely proportional to the gap, G, between the refiners plates, that is, . Figure 4.3 also shows the relationship between the net power and inverse of gap clearance is linear. According to the figure, gap was decreased as the power was increased. The relationship is strongly affected by refiner speed. The figure also highlights that at a given gap size, larger power is attained at larger velocities. Similar findings were reported by Luukkonen (2010). Also, at 1400 rpm of plate 2.74 has more effect on power than 2.01 plate.

.

Figure 4.4 Relationship between net power/refiner speed^3 and inverse of gap clearance for low consistency refining of bleached softwood kraft pulp

Luukkonen (2010) have tried to link the intensity to the gap clearance for low consistency refining (LCR), using the following relation:

Figure 4.4 is plotted using Luukkonen (2010) equation for the gap clearances used in Figure 4.3. As the figure (Fig. 4.4) shows the curves overlapped indicating that normalizing to refiner speed cubed eliminates power distinctions due to refining speed. Power normalized to refining speed might be used for estimating refiner gap.

Figure 4.5 Relationship between SEL and inverse of gap clearance for low consistency refining of bleached softwood kraft pulp

Figure 4.5 shows the relationship between SEL and 1/Gap. According to the figure, SEL versus 1/Gap is influenced by refiner speed. SEL increased as the refiner gap was reduced. SEL increase due to changes in refiner speed is marginal, indicating that the SEL is not a good predictor of intensity than gap clearance.

4.2 Comparison with a Preliminary Theoretical Model

From a fundamental standpoint, power is linked to gap size through shear on pulp, which in turn depends on the amount of fibre captured and the nature of compression and shear imposed during bar crossings. Based on a mechanistic model of this process, Kerekes (2012) has suggested an approximate form for power, expressed through SEL, as follows:

(1)

We may compare this form to our data examine this by plotting SEL against gap size, G. This may be done conveniently by a semi-logarithmic plot. To bring the value of the variables into a convenient range, we multiply both sides of (1) by 100. This gives

(2)

Figure 4.6 Plot of ln(100SEL) against gap size.

In Fig 4.6, the very large gap size of 2.5 mm is surely in the no-load range.. It gives a value ln(100SEL)=0, suggesting that SEL=0.01 corresponds to no-load. Extrapolating the data from the smaller gap sizes to ln(100SEL) =0 suggests that a gap size of 1.5 mm and larger corresponds to no-load.

It is apparent that fit of the form of the theoretical equation to the data is good. This suggests that an approach based on fundamentals is promising and worthy of further investigation.

4.3 Critical gap and fiber cutting

Fiber shortening is due to fiber cutting by refiner, so it is important to understand this results because it is a limitation of LC refiner (Olson, 2003). Figure 4.7 and 4.8 show fiber length as a function of gap clearance. According to the figure, when the refining gap was too narrow, then fiber shortening became more severe. At the critical refining gap (namely at about 0.25-0.45 mm), the fiber length dropped, but the drop was more significant when refining speed was 1400 rpm. The fibers were fibrillated by refiner when the refiner gap was wider than critical gap but when the gap size was less than the critical refining gap, then the fibers were cut by refiner. (Mohlin, 2003)

Figure 4.7 shows that refining speed influences the cutting role of the refiner, specifically if the gap clearance is less than the critical refining gap. This observation was confirmed by two different plates having different patterns. For detailed information the reader is referred to Appendix B.

Figure 4.7 Length weighted average fiber length of bleached softwood kraft pulp for various plate gaps of plate 2.74 BEL using different refiner speed

Figure 4.8 Mean length weighted fiber length of bleached softwood kraft pulp for various inverse of gaps of plate 2.74 BEL using different refiner speed.

Figure 4.9 Relationship between net power/refiner speed^3 and inverse of gap clearance at low consistency refining of bleached softwood kraft pulp

Figure 4.9 shows relationship between the power normalized to refiner speed versus the gaps of two plate patterns. According to the figure, the relationship of the power and refiner gap clearance was linear prior to critical refining gap, but the trend was changed as the gap clearance was higher than the critical refining gap. The relationship between the power (power normalized to the refiner speed) and gap seems to be linear for the gap sizes of less than the critical refining gap, but it is non-linear when the gap size remains higher than the critical gap. Beyond the refining critical gap, the power is independent of the gap clearance, but it depends on the refiner speed. These observations were valid for all the plates. Olson (2012) hypothesized that the sudden change in slope of the relationship between power and gap indicates a mechanistic change in energy transfer to the fibres and may correspond to a reduction of the number of fibres between the bars.

Figure 4.10 Relationship between freeness and gap clearance at low consistency refining of bleached softwood kraft pulp

Freeness is one of the refining indicators that estimates drainage ability of fiber after refining and it is a useful tool for controlling the wet end performance. Figure 4.10 shows that freeness is dramatically dropped for the gap sizes near or lower than the critical refining gap. This is due to the fact that the fibers at the smaller gap sizes shortened, fibrillated and mostly converted into fines, thus reducing the freeness sharply.

Figure 4.11 Relationship between tensile index and inverse gap clearance at low consistency refining of bleached softwood kraft pulp

Figure 4.12 Relationship between tear index and inverse gap clearance at low consistency refining of bleached softwood kraft pulp

As Figures 4.11 and 4.12 suggests, the paper properties were strongly influenced by refining gap. The increase in tensile was sharp as well as the changes in tear strength, but in reverse direction for the gap sizes smaller than the critical refining gap, indicating higher bonding and lower fiber strength or probably fiber shortening. It should be cautioned that the reduction in tear in the process of refining is barely related to fiber cutting. Therefore, tear index depend very much on fibre length that it is strongly influenced by cutting. So, with tear results per se, it could not be concluded that the fiber cutting takes place. In both cases the changes were minimal for either the tensile strength or tear strength when the gap size was higher than the critical refining gap. Mohlin (2006) also reported similar results. These observations suggest that the refining gap is a good indicator of refining intensity. These conclusions were also supported by Mohlin and Lukkonneen.

4.3 Effect of refining on fiber properties

To understanding of the refining process it is important to evaluate the refining result in terms of changes in fiber as well as paper properties.

In addition to fiber properties, Mohlin (2002) suggests measure of water retention value (WRV). WRV is the measure of water holding capacity of fibers, which relates to swelling capacity of fibers due to fibers internal and external fibrillation. Figure 4.13 shows the relationship between refining energy and water retention value. It seems refining increases water holding capacity of fibers, thus bringing about fiber swelling or fiber flexibility. Increase in WRV also suggests increase in tensile strength (see Figure 4.14). It should be cautioned that WRV emphasize water holding capacity, which is indirectly proportional to swelling, or as a consequence fiber flexibility. Water holding capacity suggests water deposition in fibrillated fibers including both external and internal fibrillation, but swelling mainly addresses internal fibrillation.

However, tensile strength depends not only to fiber flexibility but also specific bond strength. Specific bond strength does not originate from swelling or flexibility. Refining not only strengthens water holding capacity of the fibers but also increases specific bonding strength of the fibers. Most literature holds that RBA is the main factor and that specific bond strength change is relatively unimportant. However, some recent work suggests specific bond strength may be more important than thought, but some of this work was based on refining recycled paper. Water retention values are also quite different for different plates indicating the plate pattern effect on fiber properties. WRV of plate 2.74 was very different from the WRV of 2.01 (Figure 4.13).

Figure 4.13 Relationship between water retention value and specific energy at varying refining speed and plate pattern

Figure 4.14 Relationship between water retention value and tensile index at varying refining speed and plates

Figure 4.15 Relationship between tensile index and specific energy at varying refining speed and plates

Figure 4.16 Relationship between tensile index and specific energy at varying refining speed and plates

Tensile strength development in refining is a good indicator of refining effect. Tensile strength is sensitive to fiber-to-fiber bonding. Figure 4.15 and 4.16 shows relationship between tensile strength and specific energy. According to the figures, increase in specific energy increases tensile strength. Figure 4.15 also suggests that the tensile is higher for refiner speed of 1000 rpm when compared to the higher refiner speeds for the same refining plate. Figure 4.17 shows the tensile strength of plate 2.74 BEL is higher than the tensile strength of plate 2.01 BEL at the same refiner speed. It seems 1000 rpm is an optimum refining speed for higher tensile strength regardless to plate types.

Figure 4.17 Relationship between tensile index and specific energy at refiner speed of

1200 rpm and varying plates

Figure 4.18 shows relationship between tear index and specific energy at the different refiner speed and plate. Tear index decreased when specific energy increased due to change in fiber length, but most probably due to increase in fiber to fiber bonding and weakening of fiber strength. Fiber length is the more important. It is a common knowledge that to pull a fiber from the network requires more energy than to break the fiber. Refining weakens the fibers due to fibrillation, and at the same time increases the bonding potential of the fibers, thus causing the fibers to break instead of being pulled out from the network. More likely, even modest fiber shortening is more important. In fact, even after a lot of beating, fiber strength stays remarkably constant. No correlation was observed between the refining speed and the tear strength and the tear was higher for 2.01 plate as compared with plate 2.74 (Figure 4.18).

Figure 4.18 Relationship tear index and specific energy at varying refining speed and plates

Figure 4.19 Slope of tensile index and specific energy for different intensities calculated using the specific Edge Load theory

Figure 4.19 is a plot of change in tensile strength increase from unrefined condition normalized to specific refining energy versus specific edge load (SEL). As the figure suggests, there is no change in tensile due to increase in SEL. Therefore, at a given refining energy, the tensile strength remains independent of the SEL. This may suggest that tensile strength increase in this range is not influenced by SEL.

An alternative approach for analyzing these data is to plot increases in tensile strength for differing intensities at a common specific energy in Fig 4.20. This avoids ambiguities introduced by the non-linear dependence of tensile strength on energy. It permits direct comparison of tensile strength to SEL. Such a plot is shown below for a common specific energy of 100 kWh/ton. This too shows the SEL has no clear influence on tensile strength increase.

Figure 4.20 Relationship between Tensile index and S.E.L of softwood kraft pulp by using low consistency refiner compare at 100 kWh/ton

Figure 4.21 Slope of tensile index and specific energy at different intensities calculated using the Specific Edge Load theory

Figure 4.21 shows the data for delta tensile/delta energy plotted for different gap sizes. Here too the data is scattered. However, the graph might be indicates that at gap sizes between 0.25-0.35 mm the delta tensile/delta SRE at 1000 rpm for plate BEL 2.74 is maximum. To the left of the critical gap sizes namely gap sizes less than 0.25-0.35, see also Figure 4.19, the intensity is high, thus fiber cutting takes place, but for the right hand side of the critical refining gap the refining intensity is insufficient to create permanent deformations in the fibre cell wall, thus energy is consumed by the elastic deformations instead. (Luukkonen, 2010)

Figure 4.22 Relationship between tensile index and gap size of softwood kraft pulp by using low consistency refiner compare at 100 kWh/ton

As in the case of SEL, these data may be examined for a constant specific energy of 100 kWh/ton. This is shown in Figure 4.22. This graph shows no apparent influence of gap size on tensile strength and consequently no optimum. Thus, comparison at a common energy differs from comparison based on tensile/energy ratio. This suggests that some clarification is needed on how the influence of gap size should be assessed.

Chapter 5

Conclusion

The objective of this study was to investigate the role of low consistency refining on fiber cutting as well as finding a better method of controlling refining intensity at low consistency refining. The raw material used for this project was bleached softwood kraft pulp.

The observations suggested that fiber shortening takes place in low consistency refining where the raw material for refining is bleached softwood kraft pulp. Fiber cutting occurred where refining was conducted prior to the region referred as critical gap size. Also, it was observed in power, tensile index and tear index. The critical gap size for the pulp was in the range of 0.25 mm to 045 mm for the refining speeds practiced here.

It was observed that where the gap size was smaller than the critical gap size, cutting took place. The refining speed also accelerated the cutting. If the gap size was higher than the critical gap size, then no fiber shortening was observed.

It was also speculated that the lower gap sizes (namely lower than the critical gap size) correspond to higher refining intensity. Most importantly, when the tensile strength of the refined pulp was judged in relation to specific edge load (SEL) compare with gap size, it was observed that the SEL is insensitive to tensile variation more than gap size. It was concluded that the gap size is a better tool for papermakers to control the refining action than the SEL.

Reference

Batchelor W. J., Martinez D. M., Kerekes R. J. and Ouellet D., 1997, “Force on fibres in low consistency refining: Shear force”, Journal of Pulp and Paper Science, Vol. 23 No. 1, pp. J40-J45

Batchelor W.J., 2001, “Effects of Flocculation and Floc Trapping on Fibre Treatment in Low-Consistency Refining”, Journal of Pulp and Paper Science, Vol. 27 No. 7

Batchelor W.J., Lundin T. and Fardim P., 2006, “A method to estimate fiber trapping in low consistency refining”, TAPPI, Vol. 5 No. 8, pp. 31-36.

Genco J.M., 1999, “Fundamental Process in Stock Preparation and Refining”, Department of Chemical Engineering, University of Maine Orono.

Goosen D.R., Olson J.A. and Kerekes R.J., 2007, “The Role of Heterogeneity in Compression Refining”. J. Pulp Paper Sci. 33(2), pp.110-114.

Heymer J. O, 2009, “Measurement of Heterogeneity in Low Consistency Pulp Refining by Comminution Modeling”, Doctor thesis University of British Columbia.

Joy E. and Rintamaki J., 2010, “Utra-low Intensity Refining of Short Fibers Pulps”

Kerekes R. J., 1990, “Characterization of pulp refiners by a C-factor”, Nordic Pulp and Paper Research Journal (1) pp. 3-8.

Kerekes R. J. and Senger J. J., 2006, “Characterizing refining action in low-consistency refining by forces on fibres”, Journal of Pulp and Paper Science, 32(1), pp. 1-8.

Kerekes R. J., 2010, “Energy and Forces in Refining:, Journal of Pulp and Paper Science, 36(1-2), pp. 10-15.

Kerekes, R. J.(2012) Private Communication.

Koskenhely K., Nieminen K., Hiltunen E. and Paulapuro H., 2005, “Comparison of plate and Conical filling in refining of bleached softwood and hardwood pulps”, Paper and Timber, Vol. 87 No. 7

Loijas M., 2010, “Factor Affecting the Axial Force in Low-Consistency Refining”, Thesis of Tempere University of Appiled Sciences.

Lumiainen J., 1990, “A New Approach to the Critical Factors Effecting Refining Intensity and Refining Result in Low-Consistency refining”, TAPPI papermaking Conference

Lumiainen J., 1994, “Is the Lowest Refining Intensity the Best in Low Consistency Refining of Hardwood”, TAPPI papermaking Conference

Lundin T., 2008, “Tailoring Pulp Fibre Properties in Low Consistency Refining”, Doctoral Thesis, Laboratory of Fibre and Cellulose Technology, Abo Academy University, Turku, Finland.

Luukkonen. A, 2011, “Development of A Methodology to Optimize low consistency refining of mechanical pulp”, Doctor Thesis University of British Columbia.

Luukkonen, A, Olson J. A. and Martinez D. M, 2010, “Low consistency refining of mechanical pulp: A methodology to relate operating conditions to paper properties”, J. Pulp Paper Sci. 1-2.

Martinez D. M. and Kerekes R. J., 1994, “Forces on fibres in low consistency refining”, TAPPI., 77(12), pp. 119-125.

Martinez D. M., Batchelor W. J., Kerekes R. J. and Ouellet D., 1997, “Force on fibres in low consistency refining: Normal force”, Journal of Pulp and Paper Science, 23(1), pp. J11-J18.

Mohlin U.B., 2001, “On the complexity of LC refining-Changing consistency and flow rate in the Beloit DD-refiner”, STFI AB, Swedish Pulp and Paper Research Institute.

Mohlin U.B., 2002, “Industrial Refining of Unbleached Kraft Pulps-The effect of pH and Refining Intensity”, STFI AB, Swedish Pulp and Paper Research Institute.

Mohlin U. B., 2003, “On the complexity of LC refining: changing consistency and flow rate in the Beloit DD Refiner”, Scientific and technical advances in refining and mechanical pulping, Pira Intl., Leatherhead, UK.

Mohlin U. B., 2006, “Refining intensity and gap clearance”, 9th Pira Int. Ref, Conf., Vienna, Austria.

Mohlin U. B., 2007, “Refiner response gap clearance: power relationship and effect of fibre properties”, Refining and Mechanical Pulping, Pira Int., Leatherhead, UK.

Nazhad M., Stoere P. and Kerekes R., 2001, “An Experimental Study of The Effect of Refining on Paper Formation”, TAPPI, Vol. 84 No.7

Olson J.A., 2003 “Characterizing fibre shortening in low consistency refining using a comminution model”, Powder Technology, vol. 129, p 122-129.

Olson, J.A., Elahimehr A., Martinez, D.M.,A, 2012, “New Framework for Understanding LC Refining”, submitted to Paper Physics Conference, Stockholm.

Page D. H., 1989, “The beating of chemical pulps-the action and the effect”, Fundamentals of Papermaking.

Soupajarvi T., Kelalainen K., Lllikainen M. and Niininmaki J.,2009, “Effect of High Intensity on Mechanical Properties of Low Consistency Pulp”, TAPPI Engineering, Pulping and Environment Conference.

Appendix A

Summarize data

Table A1 Summarize refining data from Low consistency refiner of Softwood kraft pulp using plate 2.74 km/rev

Run

Gap

P no-laod

P total

P net

Refiner speed

Flow

Consist

S.R.E

S.E.L

no.

mm

kW

kW

kw

rpm

ml/min

%

kWh/odt

J/m

PP-1000-2.5

2.49

16.33

16.33

0.00

1016

194

3.57

0.00

0.00

PP-1000-G1

0.44

 

28.01

11.68

1016

190

3.51

29.13

0.25

PP-1000-G2

0.26

 

36.19

19.86

1016

188

3.52

49.84

0.43

PP-1000-G3

0.20

 

46.46

30.13

1017

189

3.43

77.27

0.65

PP-1000-G4

0.10

 

56.03

39.69

1016

221

3.43

87.21

0.86

PP-1200-2.5

2.45

26.64

26.64

0.00

1217

191

3.54

0.00

0.00

PP-1200-G1

0.48

 

36.75

10.12

1216

203

3.36

24.66

0.18

PP-1200-G2

0.35

 

49.03

22.39

1217

172

3.57

60.80

0.40

PP-1200-G3

0.27

 

61.71

35.08

1216

209

3.54

79.00

0.63

PP-1200-G4

0.18

 

67.84

41.21

1216

216

3.59

88.61

0.74

PP-1200-G5

0.06

 

77.23

50.59

1216

206

3.29

124.42

0.91

PP-1400-2.5

2.52

42.18

42.18

0.00

1406

208

3.15

0.00

0.00

PP-1400-G1

0.76

 

49.94

7.76

1406

204

3.36

18.91

0.12

PP-1400-G2

0.65

 

54.31

12.13

1405

214

3.53

26.84

0.19

PP-1400-G3

0.46

 

71.88

29.71

1405

187

3.35

78.91

0.46

PP-1400-G4

0.42

 

84.57

42.39

1406

223

3.51

90.08

0.66

PP-1400-G5

0.28

 

94.51

52.33

1405

225

3.48

111.39

0.82

PP-1400-G6

0.16

 

103.39

61.21

1405

177

3.28

175.46

0.95

Table A2 Summarize refining data from Low consistency refiner of Softwood kraft pulp using plate 2.01 km/rev

Run

Gap

P no-laod

P total

P net

Refiner speed

Flow

Consist

S.R.E

S.E.L

no.

mm

kW

kW

kw

rpm

ml/min

%

kWh/odt

J/m

2PP-1000-2.5

2.48

15.90

15.90

0.00

1016

216

3.18

0.00

0.00

2PP-1000-G1

0.45

 

25.86

9.96

1017

233

3.14

22.61

0.29

2PP-1000-G2

0.35

 

35.29

19.39

1016

203

3.35

47.57

0.57

2PP-1000-G3

0.24

 

45.50

29.60

1017

199

3.28

75.76

0.87

2PP-1000-G4

0.09

 

57.05

41.15

1018

225

3.12

97.74

1.21

2PP-1000-G5

0.05

 

65.54

49.64

1017

207

2.99

133.37

1.46

2PP-1000-G6

0.03

 

68.74

52.84

1017

231

2.98

128.21

1.55

2PP-1200-2.5

2.49

25.11

25.11

0.00

1222

220

3.35

0.00

0.00

2PP-1200-G1

0.48

 

37.86

12.75

1222

225

3.25

29.03

0.31

2PP-1200-G2

0.34

 

48.92

23.80

1222

235

3.29

51.34

0.58

2PP-1200-G3

0.24

 

59.00

33.88

1222

235

3.27

73.45

0.83

2PP-1200-G4

0.15

 

63.99

38.88

1223

232

3.16

88.47

0.95

2PP-1200-G5

0.09

 

73.33

48.22

1222

222

3.24

111.89

1.18

2PP-1200-G6

0.05

 

82.84

57.73

1222

229

3.20

131.70

1.41

2PP-1400-2.5

2.44

34.72

34.76

0.00

1412

240

3.26

0.00

0.00

2PP-1400-G1

0.58

 

45.78

11.06

1411

235

3.23

24.34

0.23

2PP-1400-G2

0.44

 

56.41

21.69

1411

231

3.27

47.80

0.46

2PP-1400-G3

0.34

 

65.39

30.67

1411

240

3.23

65.84

0.65

2PP-1400-G4

0.20

 

75.24

40.52

1411

246

3.13

87.70

0.86

2PP-1400-G5

0.12

 

83.34

48.62

1411

211

3.17

120.80

1.03

2PP-1400-G6

0.09

 

94.58

59.86

1412

215

3.06

152.03

1.27

2PP-1400-G7

0.07

 

98.79

64.07

1411

231

3.23

143.25

1.36

Table A3 Summarize fiber properties from Low consistency refiner of Softwood kraft pulp using plate 2.74 km/rev

Run

Freeness

Fiber length, Lw

Fine

Kink

Curl

WRV

no.

ml csf

mm

%

index

index

g/g

PP-1000-2.5

656

2.64

29.98

1.47

0.12

0.43

PP-1000-G1

630

2.65

31.12

1.29

0.11

0.53

PP-1000-G2

588

2.65

31.82

1.20

0.11

0.59

PP-1000-G3

527

2.63

31.76

1.17

0.10

0.67

PP-1000-G4

427

2.62

32.55

1.14

0.10

0.68

PP-1200-2.5

658

2.64

29.88

1.41

0.12

0.46

PP-1200-G1

620

2.65

31.75

1.23

0.11

0.52

PP-1200-G2

534

2.65

32.04

1.13

0.44

0.64

PP-1200-G3

530

2.63

32.02

1.15

0.11

0.69

PP-1200-G4

454

2.62

31.92

1.18

0.11

0.71

PP-1200-G5

341

2.60

32.90

1.15

0.10

0.71

PP-1400-2.5

658

2.65

29.97

1.21

0.10

0.41

PP-1400-G1

634

2.65

29.99

1.07

0.09

0.47

PP-1400-G2

617

2.65

29.99

1.24

0.11

0.53

PP-1400-G3

534

2.65

30.99

1.14

0.45

0.55

PP-1400-G4

442

2.64

30.95

1.16

0.11

0.57

PP-1400-G5

297

2.60

33.05

1.15

0.11

0.62

PP-1400-G6

176

2.47

34.65

1.19

0.11

0.69

Table A4 Summarize fiber properties from Low consistency refiner of Softwood kraft pulp using plate 2.01 km/rev

Run

Freeness

Fiber length, Lw

Fine

Kink

Curl

WRV

no.

ml csf

mm

%

index

index

g/g

2PP-1000-2.5

661

2.64

35.11

1.39

0.12

0.38

2PP-1000-G1

643

2.65

33.93

1.31

0.11

0.42

2PP-1000-G2

592

2.65

33.17

1.18

0.11

0.46

2PP-1000-G3

521

2.62

33.71

1.19

0.11

0.51

2PP-1000-G4

420.1

2.61

33.06

1.16

0.11

0.54

2PP-1000-G5

328.9

2.57

34.88

1.16

0.11

0.64

2PP-1000-G6

271.8

2.50

35.20

1.18

0.11

0.68

2PP-1200-2.5

662.5

2.64

34.59

1.45

0.13

0.39

2PP-1200-G1

620.4

2.64

32.58

1.28

0.12

0.43

2PP-1200-G2

580.6

2.64

32.93

1.21

0.12

0.46

2PP-1200-G3

525.3

2.62

33.33

1.19

0.11

0.47

2PP-1200-G4

454.3

2.61

34.18

1.20

0.12

0.52

2PP-1200-G5

337.8

2.57

33.52

1.21

0.12

0.53

2PP-1200-G6

258.0

2.54

34.44

1.22

0.11

0.57

2PP-1400-2.5

649.9

2.64

34.85

1.42

0.13

0.40

2PP-1400-G1

623.5

2.67

35.69

1.23

0.12

0.44

2PP-1400-G2

592.3

2.67

35.45

1.16

0.11

0.47

2PP-1400-G3

519.0

2.63

36.05

1.10

0.11

0.47

2PP-1400-G4

422.8

2.63

36.88

1.09

0.11

0.55

2PP-1400-G5

323.8

2.59

37.21

1.14

0.10

0.58

2PP-1400-G6

240.6

2.50

38.27

1.17

0.10

0.61

2PP-1400-G7

184.1

2.44

38.93

1.21

0.11

0.64

Table A5 Summarize handsheet properties from Low consistency refiner of Softwood kraft pulp using plate 2.74 km/rev

Run

Tensile

Tear

Density

no.

Nm/g

mNm2/g

g/cm3

PP-1000-2.5

50.81

19.37

0.560

PP-1000-G1

66.80

13.86

0.595

PP-1000-G2

79.65

12.68

0.611

PP-1000-G3

88.69

11.24

0.624

PP-1000-G4

96.96

9.56

0.643

PP-1200-2.5

53.16

17.12

0.576

PP-1200-G1

61.09

13.65

0.584

PP-1200-G2

81.37

11.63

0.549

PP-1200-G3

84.31

10.94

0.565

PP-1200-G4

84.51

10.88

0.617

PP-1200-G5

98.48

9.67

0.593

PP-1400-2.5

51.21

21.04

0.511

PP-1400-G1

61.03

17.40

0.533

PP-1400-G2

65.81

13.86

0.511

PP-1400-G3

78.84

12.55

0.553

PP-1400-G4

96.06

10.27

0.645

PP-1400-G5

100.10

9.57

0.648

PP-1400-G6

107.80

9.81

0.638

Table A6 Summarize handsheet properties from Low consistency refiner of Softwood kraft pulp using plate 2.01 km/rev

Run

Tensile

Tear

Density

no.

Nm/g

mNm2/g

g/cm3

2PP-1000-2.5

50.80

20.66

0.56

2PP-1000-G1

61.61

17.60

0.58

2PP-1000-G2

77.41

13.44

0.61

2PP-1000-G3

87.81

12.77

0.62

2PP-1000-G4

91.40

12.11

0.59

2PP-1000-G5

99.25

11.69

0.61

2PP-1000-G6

101.87

10.41

0.61

2PP-1200-2.5

50.44

21.51

0.50

2PP-1200-G1

57.37

18.63

0.51

2PP-1200-G2

72.03

16.65

0.54

2PP-1200-G3

80.46

15.44

0.56

2PP-1200-G4

86.69

13.82

0.57

2PP-1200-G5

92.98

12.17

0.59

2PP-1200-G6

98.68

10.66

0.61

2PP-1400-2.5

50.11

21.03

0.50

2PP-1400-G1

58.81

18.19

0.51

2PP-1400-G2

68.42

16.31

0.54

2PP-1400-G3

78.08

13.96

0.56

2PP-1400-G4

90.18

12.55

0.58

2PP-1400-G5

97.13

11.48

0.60

2PP-1400-G6

100.50

10.30

0.63

2PP-1400-G7

106.10

10.09

0.62

Appendix B

Fiber cutting and Refiner gap size

Figure B1 Relationship between Fiber length (lw) and Gap clearance of softwood kraft pulp by using low consistency refiner

Figure B2 Relationship between Fiber length (lw) and Gap clearance of softwood kraft pulp by using low consistency refiner compare at plate 2.01 km/rev

Figure B3 Relationship between Fiber length (lw) and Gap clearance of softwood kraft pulp by using low consistency refiner compare at refiner speed 1000 rpm

Figure B4 Relationship between Fiber length (lw) and Gap clearance of softwood kraft pulp by using low consistency refiner compare at refiner speed 1200 rpm

Figure B5 Relationship between Fiber length (lw) and Gap clearance of softwood kraft pulp by using low consistency refiner compare at refiner speed 1400 rpm

Appendix C

Tensile index and Refiner gap size

Figure C1 Relationship between Tensile index and Gap clearance of softwood kraft pulp by using low consistency refiner

Figure C2 Relationship between Tensile index and Gap clearance of softwood kraft pulp by using low consistency refiner compare at refiner speed 1000 rpm

Figure C3 Relationship between Tensile index and Gap clearance of softwood kraft pulp by using low consistency refiner compare at refiner speed 1200 rpm

Figure C4 Relationship between Tensile index and Gap clearance of softwood kraft pulp by using low consistency refiner compare at refiner speed 1400 rpm

Appendix D

Pulp properties at 100 kWhr/odt

Figure D1 Relationship between Tear index and Gap clearance of softwood kraft pulp by using low consistency refiner compare at 100 kWh/odt

Figure D2 Relationship between Tear index and S.E.L of softwood kraft pulp by using low consistency refiner compare at 100 kWh/odt

Figure D3 Relationship between Fiber length and Gap clearance of softwood kraft pulp by using low consistency refiner compare at 100 kWh/odt

Figure D4 Relationship between Fiber length and SEL of softwood kraft pulp by using low consistency refiner compare at 100 kWh/odt

Figure D5 Relationship between Freeness and Gap clearance of softwood kraft pulp by using low consistency refiner compare at 100 kWh/odt

Figure D6 Relationship between Freeness and SEL of softwood kraft pulp by using low consistency refiner compare at 100 kWh/odt

2.74 km/rev, 1000 rpm2.48802662222221920.438005140000000020.259642918235294450.196146431428571910.1026994962443663816.33302076249999128.01321461181823136.18858769647054946.46332058619045656.0274775823733792.74 km/rev, 1200 rpm2.44615801101652370.479039508262393390.351067920881322490.268571239359038870.181361559339008725.6670561842764096E-226.63669726790188736.754252833249949.02726113420125461.71278515923889167.84275151126641477.2277025748621782.74 km/rev, 1400 rpm2.52036546388887170.760515294942414990.64896158437656670.455296187781672860.417106828743115830.27765623585378130.1562880525788697442.17757024222221749.94118846219296954.30712912969419671.88263114321415584.56837592739108894.512293924386597103.389155458688012.01 km/rev, 1000 rpm2.47961914944833770.446689133400200940.354786168505516310.242547802345058999.3048106318957005E-24.9767843530591833E-23.1234885975767457E-215.89969363189567625.85527368405216835.29070461083249945.50424099832493157.05429435807424565.53655000100293668.7381754312939112.01 km/rev, 1200 rpm2.48966021982973770.481407999443516980.340505148497338150.240505148497349470.151457413081911199.3484412197997163E-25.1457413081910021E-225.11169170605922637.86457568224824448.91563163936329858.99568461520298363.98753079257530673.327810868591382.844628126104782.01 km/rev, 1400 rpm2.43582077933801380.583305818455366110.439674870912740820.338784938126101440.199081722266799880.119769533099297019.0722946840521596E-27.1104929997762994E-234.76410848946839845.78131085456376356.41372990471407465.3858115951678875.23770305315947883.33843155466328894.58083246639915898.792861305917526

Gap, mm

Total power, kW

1000 rpm, 2.74 km/rev

0.438005140000000020.259642918235294450.196146431428571740.1026994962443663811.68019384931823619.85556693397058930.13029982369053539.6944568198736081200 rpm, 2.74 km/rev

0.479039508262393390.351067920881322490.268571239359038870.181361559339008725.6670561842764096E-210.1175555653480222.39056386629937435.07608789133674841.20605424336493950.5910053069603621400 rpm, 2.74 km/rev

0.760515294942414990.64896158437656670.455296187781672860.417106828743115830.27765623585378130.156288052578869747.763618219971029112.12955888747229229.70506090099247842.390805685168952.33472368216434561.2115852164658631000 rpm, 2.01 km/rev

0.446689133400200890.354786168505516310.242547802345058999.3048106318956866E-24.9767843530591833E-23.1234885975767457E-29.955580052156561219.39101097893682329.60454736642922741.154600726178649.63685636910726452.8384817993979471200 rpm, 2.01 km/rev

0.481407999443516980.340505148497338090.240505148497349470.151457413081911199.3484412197997163E-25.1457413081910014E-212.75288397618917623.80393993330445933.88399290914417638.87583908651602448.21611916253259357.7329364200456891400 rpm, 2.01 km/rev

0.5833058184553660.439674870912740820.338784938126101440.199081722266799880.1197695330992979.0722946840521596E-27.1104929997762994E-211.06154894177649321.69396799192683330.66604968238058940.51794114037219448.61866964187674359.8610705536116464.073099393130249

Gap, mm

Power (net), Kw

1000 rpm, 2.74 km/rev2.48802662222221920.438005140000000020.259642918235294450.196146431428571740.1026994962443663803.22593427116538273.75635912430372134.17295950348188524.44948129494957811200 rpm, 2.74 km/rev2.44615801101652370.479039508262393390.351067920881322490.268571239359038870.181361559339008725.6670561842764096E-202.90219306719964143.69574810538596674.14548592536024074.30650181376566544.51196862763505551400 rpm, 2.74 km/rev2.52036546388887660.760515294942414990.64896158437656670.455296187781672860.417106828743115830.27765623585378130.1562880525788692402.49256737755413172.93906859183953853.83532605896526224.19000865741827784.40135719435774144.55800923138733791000 rpm, 2.01 km/rev2.47961914944833950.446689133400200890.354786168505516310.242547802345058999.3048106318956866E-24.9767843530591833E-23.1234885975767405E-203.37512456466206514.04232214588538244.46496416547619654.79283203767000554.98139454020243385.04395060434248691200 rpm, 2.01 km/rev2.489660219829740.481407999443516980.340505148497338870.240505148497348940.151457413081910699.3484412197996858E-25.1457413081910014E-203.43888362965417294.06315860509996094.41619178143512064.55304629553254084.76844605967612984.94927952339721241400 rpm, 2.01 km/rev2.43582077933801380.5833058184553660.439674870912739440.338784938126100830.199081722266799880.1197695330992979.0722946840521596E-27.1104929997762994E-203.15306038078704013.82616721137325974.17259239742284834.45131151962431744.63329987479533134.84095748107743254.909446163486499

Gap, mm

ln(100SEL)

1000 rpm, 2.74 km/rev7.6992449948530689E-31.783885607107338E-21.3113483654941195E-31.7214674988905387E-21.2593406224181744E-27.6992449948530689E-31.783885607107338E-21.3113483654941195E-31.7214674988905387E-21.2593406224181744E-22.48802662222221920.438005140000000020.259642918235294450.196146431428571740.102699496244366382.64466666666666722.652.64599999999999992.63099999999999982.61499999999999981200 rpm, 2.74 km/rev5.1874034179701534E-39.0136994733811156E-31.4372214356885724E-26.9855995702669694E-31.5650228855466033E-27.1035259281003928E-35.1874034179701534E-39.0136994733811156E-31.4372214356885724E-26.9855995702669694E-31.5650228855466033E-27.1035259281003928E-32.44615801101652370.479039508262393390.351067920881322490.268571239359038870.181361559339008725.6670561842764096E-22.64166666666666662.64666666666667012.64800000000000012.62966666666667012.61833333333333322.59733333333333421400 rpm, 2.74 km/rev7.5171032014082154E-31.4361656442665701E-21.5190087373054599E-27.7885659228140933E-31.6171018326877711E-26.8814922812586721E-38.8709534844269768E-37.5171032014082154E-31.4361656442665701E-21.5190087373054599E-27.7885659228140933E-31.6171018326877711E-26.8814922812586721E-38.8709534844269768E-32.52036546388886640.760515294942414990.64896158437656670.455296187781672860.417106828743115830.27765623585378130.156288052578870182.65099999999999982.648833333333332.6546666666666672.64866666666666722.63533333333333312.59599999999999882.4676666666666671

Gap, mm

Fiber length, mm

1000 rpm, 2.74 km/rev0.401924959752577912.28307823054313943.85144338538737375.09823193170943969.73714610654533172.64466666666666722.652.64599999999999992.63099999999999982.61499999999999981200 rpm, 2.74 km/rev0.408804335409406972.08751049287620122.84845165428272473.72340687851225165.513847607203010717.6458458762868842.64166666666666662.64666666666667012.64800000000000012.62966666666667012.61833333333333322.59733333333333421400 rpm, 2.74 km/rev0.396767855427210821.31489794702382471.54092325967284792.19637244245833152.39746734191175913.60157587285962456.39844174586131232.65099999999999982.648833333333332.6546666666666672.64866666666666722.63533333333333312.59599999999999882.4676666666666671

1/Gap, mm-1

Fiber length (Lw), mm

1000 rpm, 2.74 km/rev0.401924959752577912.28307823054313943.85144338538737375.09823193170943969.737146106545331701.1140744005417301E-51.892916568675188E-52.8686059004293851E-53.7887306527921072E-51200 rpm, 2.74 km/rev0.408804335409406972.08751049287620122.84845165428272473.72340687851225165.513847607203010717.64584587628688405.6216790104889987E-61.2410717842204103E-51.9492189488643186E-52.2895271588403659E-52.8133291807634147E-51400 rpm, 2.74 km/rev0.396767855427210821.31489794702382471.54092325967284792.19637244245833152.39746734191175913.60157587285962456.398441745861312302.7937939315717357E-64.3688963043826488E-61.0718151074930325E-51.5252727544230691E-51.8865724734926934E-52.2064061372762982E-5

1/Gap, 1/mm

Power (net)/3

1000 rpm, 2.74 km/rev7.6992449948530637E-31.783885607107338E-21.3113483654941195E-31.7214674988905387E-21.2593406224181744E-27.6992449948530637E-31.783885607107338E-21.3113483654941195E-31.7214674988905387E-21.2593406224181744E-22.48802662222221920.438005140000000020.259642918235294450.196146431428571740.10269949624436638656.44999999999948629.65588.29999999999995527.4426.851200 rpm, 2.74 km/rev115.1874034179701534E-39.0136994733811121E-31.4372214356885724E-26.9855995702669694E-31.5650228855466033E-27.1035259281003928E-35.1874034179701534E-39.0136994733811121E-31.4372214356885724E-26.9855995702669694E-31.5650228855466033E-27.1035259281003928E-32.44615801101652370.479039508262393390.351067920881322490.268571239359038870.181361559339008725.6670561842764096E-2658.09999999999991620.20000000000005533.75529.75454.20000000000005341.051400 rpm, 2.74 km/rev7.5171032014082154E-31.4361656442665701E-21.5190087373054599E-27.7885659228140898E-31.6171018326877711E-26.8814922812586669E-38.8709534844269768E-37.5171032014082154E-31.4361656442665701E-21.5190087373054599E-27.7885659228140898E-31.6171018326877711E-26.8814922812586669E-38.8709534844269768E-32.52036546388886730.760515294942414990.64896158437656670.455296187781672860.417106828743115830.27765623585378130.15628805257887007658634617.44999999999948533.5442.4297.05176.1

Gap, mm

Freeness, CSF

1000 rpm, 2.74 km/rev1.45472245059785381.873351489472931.55719299606322292.06736398638786322.66902360980098541.45472245059785381.873351489472931.55719299606322292.06736398638786322.66902360980098540.401924959752577752.28307823054313943.85144338538737375.09823193170943969.737146106545331750.81300000000000266.879.65400000000001188.68899999999997996.9570000000000221200 rpm, 2.74 km/rev1.28540767934604451.10229868383735921.19511740384978891.90728218804217951.63709914916210191.98416171995915972.53799023461176131.28540767934604451.10229868383735921.19511740384978891.90728218804217951.63709914916210191.98416171995915972.53799023461176130.408804335409406862.08751049287620122.84845165428272473.72340687851225035.513847607203010717.64584587628688453.15900000000000661.09200000000001381.3669999999999984.31300000000000284.50998.4749999999999941400 rpm, 2.74 km/rev1.20895589236659021.55072061999861191.12132552604232631.00256388662043582.18092016990282821.82775314353789421.43373892247877641.20895589236659021.55072061999861191.12132552604232631.00256388662043582.18092016990282821.82775314353789421.43373892247877640.396767855427210821.31489794702382471.54092325967284842.19637244245833152.39746734191175913.60157587285962456.398441745861312351.2060000000000161.03400000000000665.80799999999999378.84100000000002296.059000000000012100.09899999999999107.8

1/Gap, mm-1

Tensile index, kNm/kg

1000 rpm, 2.74 km/rev0.401924959752577752.28307823054313943.85144338538737375.09823193170943969.737146106545331719.37225925117758213.85794710760367612.68339278277904311.2393008272927989.56062613994577681200 rpm, 2.74 km/rev115.1874034179701534E-39.0136994733811121E-31.4372214356885724E-26.9855995702669694E-31.5650228855466033E-27.1035259281003928E-35.1874034179701534E-39.0136994733811121E-31.4372214356885724E-26.9855995702669694E-31.5650228855466033E-27.1035259281003928E-30.408804335409406862.08751049287620122.84845165428272473.72340687851225035.513847607203010717.64584587628688417.11983477845312913.6462902344277711.63145008834646910.94390550679888510.8760457161665269.67123419426581071400 rpm, 2.74 km/rev7.5171032014082154E-31.4361656442665701E-21.5190087373054599E-27.7885659228140898E-31.6171018326877711E-26.8814922812586669E-38.8709534844269768E-37.5171032014082154E-31.4361656442665701E-21.5190087373054599E-27.7885659228140898E-31.6171018326877711E-26.8814922812586669E-38.8709534844269768E-30.396767855427210821.31489794702382471.54092325967284842.19637244245833152.39746734191175913.60157587285962456.398441745861312321.03847940880149317.40209465088798913.85944578921032612.55057303174667610.2749312605913689.56741699032412289.8147649077111137

1/Gap, mm-1

Tear Index, mNm2/g

1000 rpm, 2.74 km/rev029.12570506214284249.84459895635005577.27480391062783887.2136332353186390.433689401751351510.532850325065598710.592675585284280880.672788867030401080.67855071345789831200 rpm, 2.74 km/rev024.66179099315853360.79594953764547778.99952799123617888.614598293450598124.419937687880590.458501660487760980.518234986594089950.644489878698135230.693050526496703620.706503429871199960.710649123539961011400 rpm, 2.74 km/rev018.91186122910295726.84148614379138978.91008817289089490.082110054461396111.39137968821534175.456939365288970.410000000000000310.472001486920987810.530.550000000000000040.569993375993076650.620000000000002660.69467718476446251000 rpm, 2.01 km/rev022.60500403955311247.57424553575584375.76039104853504197.740642377844509133.37280103222687128.207741962382020.383981631626641730.421775207103045720.457148373521714450.512244962573265680.541688721867480960.639836157540897950.677026554702721200 rpm, 2.01 km/rev029.02785073672823351.34050563475838773.45135277128191888.465271117974098111.8940166857162131.698168024257910.393981631626641290.431775207103045510.455504522392556730.474642744213687520.517681269382361590.526009262624050680.5742350264696031400 rpm,2.01 km/rev024.33799211866713147.79697257520659565.84064036776274587.702936633663199120.79933041470341152.03230374599846143.246706784080350.40.437665818698830870.470000000000000080.471346909217291110.549847404407762810.580000000000000070.610000000000000650.63908609751959089

SRE, kWh/ton

Water rentention Value, g/g

1000 rpm, 2.74 km/rev50.81300000000000266.879.65400000000001188.68899999999997996.9570000000000220.433689401751351510.532850325065598710.592675585284280880.672788867030401080.67855071345789831200 rpm, 2.74 km/rev53.15900000000000661.09200000000001381.3669999999999984.31300000000000284.50998.4749999999999940.458501660487760980.518234986594089950.644489878698135230.693050526496703620.706503429871199961400 rpm, 2.74 km/rev51.2060000000000161.03400000000000665.80799999999999378.84100000000002296.059000000000012100.09899999999999107.80.410000000000000310.472001486920987810.530.550000000000000040.569993375993076650.620000000000002660.69467718476446251000 rpm, 2.01 km/rev50.80300000000000461.60600000000000977.41200000000000687.81300000000000291.39900000000000199.253101.869999999999990.383981631626641730.421775207103045720.457148373521714450.512244962573265680.541688721867480960.639836157540897950.677026554702721200 rpm, 2.01 km/rev50.44400000000000357.36700000000000472.0380.46300000000002286.69400000000000392.9799999999999998.6749999999999830.393981631626641290.431775207103045510.455504522392556730.474642744213687520.517681269382361590.526009262624050680.5742350264696031400 rpm,2.01 km/rev50.1158.81099999999999368.41599999999999778.07899999999997990.18399999999998397.128999999999948100.49600000000002106.1010.40.437665818698830870.470000000000000080.471346909217291110.549847404407762810.580000000000000070.610000000000000650.63908609751959089

Tensile index, mN/g

Water rentention Value, g/g

1000 rpm, 2.74 km/rev029.12570506214284249.84459895635005577.27480391062783887.21363323531883850.81300000000000266.879.65400000000001188.68899999999997996.9570000000000221200 rpm, 2.74 km/rev024.66179099315853360.79594953764547778.99952799123633488.61459829345047124.4199376878805953.15900000000000661.09200000000001381.3669999999999984.31300000000000284.50998.4749999999999941400 rpm, 2.74 km/rev018.91186122910298926.84148614379138978.91008817289069690.082110054461225111.39137968821554175.4569393652894651.2060000000000161.03400000000000665.80799999999999378.84100000000002296.059000000000012100.09899999999999107.8

SRE, kwhr/T

Tensile Index, kNm/kg

1000 rpm, 2.74 km/rev029.12570506214284249.84459895635005577.27480391062783887.21363323531868250.81300000000000266.879.65400000000001188.68899999999997996.9570000000000221200 rpm, 2.74 km/rev024.66179099315853360.79594953764547778.99952799123622188.61459829345057124.4199376878805953.15900000000000661.09200000000001381.3669999999999984.31300000000000284.50998.4749999999999941400 rpm, 2.74 km/rev018.91186122910296426.84148614379138978.91008817289083890.082110054461339111.39137968821539175.4569393652890651.2060000000000161.03400000000000665.80799999999999378.84100000000002296.059000000000012100.09899999999999107.81000 rpm, 2.01 km/rev022.60500403955311247.57424553575584375.76039104853504197.740642377844509133.37280103222687128.2077419623820250.80300000000000461.60600000000000977.41200000000000687.81300000000000291.39900000000000199.253101.869999999999991200 rpm, 2.01 km/rev029.02785073672823351.34050563475838773.45135277128191888.465271117974069111.89401668571624131.6981680242578550.44400000000000357.36700000000000472.0380.46300000000002286.69400000000000392.9799999999999998.6749999999999831400 rpm, 2.01 km/rev024.33799211866713147.79697257520659565.84064036776274587.702936633663171120.79933041470341152.03230374599846143.2467067840803550.1158.81099999999999368.41599999999999778.07899999999997990.18399999999998397.128999999999948100.49600000000002106.101

SRE, kwhr/T

Tensile Index, kNm/kg

1200 rpm, 2.74 km/rev024.66179099315853360.79594953764547778.99952799123633488.61459829345047124.4199376878805953.15900000000000661.09200000000001381.3669999999999984.31300000000000284.50998.4749999999999941200 rpm, 2.01 km/rev029.02785073672823351.34050563475838773.45135277128191888.46527111797397111.89401668571639131.6981680242576850.44400000000000357.36700000000000472.0380.46300000000002286.69400000000000392.9799999999999998.674999999999983

SRE, kwhr/T

Tensile Index, kNm/kg

1000 rpm, 2.74 km/rev029.12570506214284249.84459895635005577.27480391062783887.21363323531873819.37225925117758213.85794710760367612.68339278277904311.2393008272927989.56062613994577681200 rpm, 2.74 km/rev5.1874034179701534E-39.0136994733811017E-31.4372214356885724E-26.9855995702669694E-31.5650228855466033E-27.1035259281003928E-35.1874034179701534E-39.0136994733811017E-31.4372214356885724E-26.9855995702669694E-31.5650228855466033E-27.1035259281003928E-3024.66179099315853360.79594953764547778.99952799123624988.614598293450541124.4199376878805917.11983477845310413.6462902344277711.63145008834646910.94390550679888510.8760457161665259.67123419426581071400 rpm, 2.74 km/rev7.5171032014082154E-31.4361656442665701E-21.5190087373054599E-27.7885659228140777E-31.6171018326877711E-26.8814922812586539E-38.8709534844269768E-37.5171032014082154E-31.4361656442665701E-21.5190087373054599E-27.7885659228140777E-31.6171018326877711E-26.8814922812586539E-38.8709534844269768E-3018.91186122910297126.84148614379138978.91008817289079590.082110054461296111.39137968821544175.456939365289221.03847940880149317.40209465088798913.85944578921032612.55057303174667610.2749312605913689.56741699032412289.81476490771111371000 rpm, 2.01 km/rev022.60500403955311247.57424553575584375.76039104853504197.740642377844509133.37280103222687128.2077419623820220.65773179367127817.60399360063960113.44142101234551812.76901734273999612.11243196920682211.69457844692933810.4106719305523191200 rpm, 2.01 km/rev029.02785073672823351.34050563475838773.45135277128191888.465271117974041111.8940166857163131.698168024257821.50780777106470518.62531036989570116.64744091316511615.4424475215934713.8180600786413212.16658969044370210.6572702141470221400 rpm, 2.01 km/rev024.33799211866713147.79697257520659565.84064036776274587.702936633663143120.79933041470341152.03230374599846143.2467067840803521.02931531018063218.19470673030148316.31209628478838913.96439607168982612.5450005971511.47912197250237310.2964674089671510.092937970602074

SRE, kWhr/T

Tear Index, mNm2/g

0.251770853960850360.427923404149144650.64907261403387750.855825403910779880.182140462281744910.402756917823473170.631482998078888640.741805371915641110.911009860142649510.463085245161718890.660233625498030.815614883735936490.953933845192021510.292279243210050110.569584551963518980.8691791482185861.20642549561566261.45677393048125411.55081471954971260.311521613996885660.581577185369810070.82780438330740580.949211261342343571.17736144793507561.41073287295284790.234075912181784220.458863281652403980.648834379275894160.857393190945913491.02852906447986791.26590501731431911.35564313146926010.548896583478064690.578618357933959220.490146827726738340.529091591397129690.321671690519180320.463978278397206960.394356786580503770.353779180899554350.364218153795252850.350208707655374870.497912404281860790.438929835835161870.322552075767013170.477903033376922470.559315228236278110.488513845926296380.415344108779894920.36326747001656690.39831447944059650.238495094341949740.42044774848080030.408692268656716150.409765318546959250.380145438155766570.366223773068097390.3575068952925850.38299496837789210.424798419999791680.456928827450669260.389232289935583680.33141640795091160.3908711149946173

SEL, J/m

deltaTensile/deltaSRE

1000 rpm, 2.74 km/rev1.1218141752864919107.593834274612721200 rpm, 2.74 km/rev0.7956091090564552188.9499164365692391400 rpm, 2.74 km/rev0.791020642836958598.7296993114377411000 rpm, 2.01 km/rev1.222299544953926791.8970050447273931200 rpm, 2.01 km/rev1.037202772328085489.559685548386981400 rpm, 2.01 km/rev0.920979232827795792.764435368403539

S.E.L, J/m

Tensile index, Nm/g (@100 kWh/ton)

0.438005140000000020.259642918235294450.196146431428571740.102699496244366380.479039508262393390.351067920881322490.268571239359038870.181361559339008725.6670561842764096E-20.455296187781672860.417106828743115830.27765623585378130.156288052578869930.446689133400200890.354786168505516310.242547802345058999.3048106318956866E-24.9767843530591833E-23.1234885975767481E-20.481407999443516980.340505148497337760.240505148497349690.151457413081911389.348441219799726E-25.1457413081910014E-20.5833058184553660.439674870912741430.338784938126101660.199081722266799880.1197695330992979.0722946840521596E-27.1104929997762994E-20.548896583478064690.578618357933959220.490146827726738340.529091591397129690.321671690519180320.463978278397206960.394356786580503770.353779180899554350.364218153795252850.350208707655374870.497912404281860790.438929835835161870.322552075767013170.477903033376922470.559315228236278110.488513845926296380.415344108779894920.36326747001656690.39831447944059650.238495094341949740.42044774848080030.408692268656716150.409765318546959250.380145438155766570.366223773068097390.3575068952925850.38299496837789210.424798419999791680.456928827450669260.389232289935583680.33141640795091160.3908711149946173

Gap, mm

deltaTensile/deltaSRE

1000 rpm, 2.74 km/rev-1.7520576690425931E-2107.593834274612721200 rpm, 2.74 km/rev0.1417122467030867488.9499164365692391400 rpm, 2.74 km/rev0.2992364899672600498.7296993114377411000 rpm, 2.01 km/rev9.0303799060778414E-291.8970050447273931200 rpm, 2.01 km/rev0.1187250710978522489.559685548386981400 rpm, 2.01 km/rev0.1696130429185871792.764435368403539

Gap, mm

Tensile index, Nm/g (@100 kWh/ton)

1000 rpm, 2.74 km/rev0.401924959752576362.28307823054313943.85144338538737375.09823193170943969.73714610654533172.64466666666666722.652.64599999999999992.63099999999999982.61499999999999981200 rpm, 2.74 km/rev0.408804335409405422.08751049287620122.84845165428272473.72340687851224185.513847607203010717.6458458762868842.64166666666666662.64666666666667012.64800000000000012.62966666666667012.61833333333333322.59733333333333421400 rpm, 2.74 km/rev0.396767855427210821.31489794702382471.54092325967285222.19637244245833152.39746734191175913.60157587285962456.39844174586131232.65099999999999982.648833333333332.6546666666666672.64866666666666722.63533333333333312.59599999999999882.46766666666666711000 rpm, 2.01 km/rev0.40328773885395882.23869336687909512.81859916978260694.122898621762636210.74712898048805520.09329577210455432.0154842497525392.63766666666666662.65366666666667022.64833333333332992.62466666666666712.60600000000000032.57133333333333352.49799999999999981200 rpm, 2.01 km/rev0.401661235551405542.07724009812040712.9368131566087294.15791514754627486.602516044950434110.69697050543611819.4335459189951292.64366666666666992.64299999999999982.64166666666667022.61633333333332672.61266666666666672.5692.53566666666666671400 rpm, 2.01 km/rev0.410539235268274181.71436657814946282.27440790037434142.95172508415290755.02306283376354838.34936877620565111.0225696455590514.0637224455668642.6406666666666682.66800000000000012.6666666666672.6252.62633333333333012.58733333333334012.5006666666666672.438333333333333

1/G, mm-1

Fiber length, mm

1000 rpm, 2.01 km/rev0.40328773885395882.23869336687909512.81859916978260694.122898621762636210.74712898048805520.09329577210455432.0154842497525392.63766666666666662.65366666666667022.64833333333332992.62466666666666712.60600000000000032.57133333333333352.49799999999999981200 rpm, 2.01 km/rev0.401661235551405542.07724009812040712.9368131566087294.15791514754627486.602516044950434110.69697050543611819.4335459189951292.64366666666666992.64299999999999982.64166666666667022.61633333333332672.61266666666666672.5692.53566666666666671400 rpm, 2.01 km/rev0.410539235268274181.71436657814946282.27440790037434142.95172508415290755.02306283376354838.34936877620565111.0225696455590514.0637224455668642.6406666666666682.66800000000000012.6666666666672.6252.62633333333333012.58733333333334012.5006666666666672.438333333333333

1/G, mm-1

Fiber length, mm

1000 rpm, 2.74 km/rev7.6992449948530221E-31.783885607107338E-21.3113483654941195E-31.7214674988905387E-21.2593406224181744E-27.6992449948530221E-31.783885607107338E-21.3113483654941195E-31.7214674988905387E-21.2593406224181744E-22.48802662222221920.438005140000000020.259642918235294450.196146431428571740.102699496244366382.64466666666666722.652.64599999999999992.63099999999999982.61499999999999981000 rpm, 2.01 km/rev2.47961914944833860.446689133400200890.354786168505516310.242547802345058999.3048106318956866E-24.9767843530591833E-23.1234885975767415E-22.63766666666666662.65366666666667022.64833333333332992.62466666666666712.60600000000000032.57133333333333352.4979999999999998

Gap, mm

Fiber length, mm

12