Understanding of no‐load power in low consistency refiners

Nasab, Nina Rajabi; Olson, James A.; Heymer, Jens; Martinez, Mark

doi:10.1002/cjce.21818

Cited by 9 publications

(7 citation statements)

References 12 publications

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“…Recently, authors experimentally showed that the measured power as a function of gap size for an LC refiner, when there is no refining action on fibres, is similar when running a refiner with either low consistency mechanical pulp or water . Thus, in this study, water has been considered as the fluid between two corrugated walls with the density of

998.3 {normalkg / m}^{3}

and viscosity of

0.001003

kg/m.s.…”

Section: Computational Frameworkmentioning

confidence: 94%

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Turbulent couette flow between corrugated walls: The case with motion of one wall perpendicular to the corrugation cavities

et al. 2014

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In this work, we numerically examine the two dimensional flow of a Newtonian fluid in the gap formed between two opposing cavities. The fluid is driven by the motion of the upper cavity and the case considered represents a simplified version of the geometry found in Low Consistency (LC) refiners. Numerical studies were conducted in which we characterized the effect of gap size on the flow field. Then, we examine material transport between the cavities by introducing a passive scalar to represent the motion of tracer particles. A large number of unsteady simulations were conducted over the range of velocities and gap sizes. Over the range of parameters studied, we identify two characteristic flow fields, defined as either steady or unsteady.

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998.3 {normalkg / m}^{3}

and viscosity of

0.001003

kg/m.s.…”

Section: Computational Frameworkmentioning

confidence: 94%

“…In the LC refiner, fibres experience the effect of refining only in the range of very small gap sizes while consuming high amount of energy. As gap slowly increases, the effect of the refiner on fibres diminishes, the power consumption decreases, and ultimately, approaches a minimum constant value at wide gaps …”

Section: Introductionmentioning

confidence: 99%

Turbulent couette flow between corrugated walls: The case with motion of one wall perpendicular to the corrugation cavities

et al. 2014

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“…The LC refining process is usually characterized by the refining intensity and specific refining energy. Most refining intensities, such as the specific edge load (SEL) [5] , specific surface load (SSL) [6] , and net normal force or tangential force per bar crossing zone [7] , have been proposed and calculated based on the net power obtained by subtracting the no-load power from the total power [8][9] . This indicates that the accurate measurement or calculation of net power is important for controlling LC refining.…”

Section: Introductionmentioning

confidence: 99%

“…Refining efficiency, defined as the ratio of net power to total power [10] , can be improved by increasing the net power or reducing the no-load power, which is approximately in the range of 20%-50% of the total power in LC refining [11] , and is related to refining devices, plate size, and other control or bar parameters [12] . The definition, calculation, and measurement methods for the no-load power have been summarized in previous studies [9,12] .…”

Section: Introductionmentioning

confidence: 99%

Effect of Refiner Plate Bar Angle and Pulp Properties on the Low Consistency Refining Efficiency in Terms of Power Consumption

Liu,

Dong,

et al. 2023

Paper and Biomaterials

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Power consumption is the energy source of the impact on fibers or pulp during low-consistency (LC) pulp refining, and the strength of refining affects refining quality and efficiency. The pulp properties, operating parameters, and bar parameters of the refiner plates are important parameters affecting refining efficiency, which can be defined as the ratio of net to total refining power. In this study, LC refining trials for pulps with different consistencies and fiber lengths were conducted using five isometric straightbar plates with different bar angles to explore the influences of the plate bar angle and pulp properties on the no-load power, impact capacity on fibers and refining efficiency. It was found that the no-load power of the LC refining process decreased with an increase in the plate bar angle while increased when pulp with higher consistency was refined under the same refining conditions. However, the effect of pulp consistency on the no-load power can be neglected when refining is conducted using plates with larger bar angles.Meanwhile, a critical bar angle for straight-bar plates in LC refining may exist, which has the strongest impact on the pulp and highest refining efficiency under the same refining conditions. In addition, the impact

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“…The no-load power of disc refiner in LC refining increase with the increasing of the plate diameter (Rajabi Nasab et al, 2013;Banks, 1967), and the net power is proportional to the rotation speed of the plates, while the no-load power is proportional to the cube of it (Ragnar, 1970). The pulp properties, such as pulp consistency, pulp type, etc., would affect the power consumption and the impact performance on pulp in the LC refining.…”

Section: Introductionmentioning

confidence: 99%

Effect of Pulp Properties on the Power Consumption in Low Consistency Refining

Liu¹,

Ji-xian²,

Qi³

et al. 2020

Journal of the Korean Wood Science and Technology

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The power consumption in the low consistency (LC) refining is an important indicator for the optimal control of the process and it is composed of the net power and the no-load power. The refining efficiency and process characterization of LC refining are directly affected by power consumption. In this paper, the effect of pulp consistency and average fiber length on the power consumption and refining efficiency were studied through the LC refining trials conducted by an experimental disc refiner. It is found that the curve of power-gap clearance can be divided into constant power section, power reduction section, and power increase section. And the no-load power and the adjustable domain of loading applied by the refining plates will increase as the increase of pulp consistency, while the increase of net power is larger than that of no-load power which makes the increasing of refining efficiency. Meanwhile, the adjustable domain of loading applied by the refining plates can be slightly improved by increasing the average fiber length, but its effect on the no-load power in the LC refining process can be neglected. The study of power consumption in LC refining is of positive significance for the proper selection of pulp properties in LC refining, in-depth exploration of refining mechanism, and energy consumption reduction in refining.

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Understanding of no‐load power in low consistency refiners

Cited by 9 publications

References 12 publications

Turbulent couette flow between corrugated walls: The case with motion of one wall perpendicular to the corrugation cavities

Turbulent couette flow between corrugated walls: The case with motion of one wall perpendicular to the corrugation cavities

Effect of Refiner Plate Bar Angle and Pulp Properties on the Low Consistency Refining Efficiency in Terms of Power Consumption

Effect of Pulp Properties on the Power Consumption in Low Consistency Refining

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