Bar forces in pulp refiners

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
R. J. Kerekes ◽  
J. D. McDonald
Keyword(s):  
Fibre Properties ◽  
Pulp Properties ◽  
Piezo Electric

Abstract Refiners develop pulp properties by applying forces on fibres during bar crossings. The size of these forces is critical in developing fibre properties while avoiding fibre shortening. This study has shown that bar force calculated from Specific Edge load (SEL) gives the same result as vector-based derivations of average bar force. Predicted forces agree reasonably well with ones measured by a novel piezo-electric sensor in refiner bars and forces estimated from measurements of fibre shortening.

scholarly journals Effect of Fibre Properties on Flocculation and Fractionation of Cellulosic Fibres in Dry State

2009 ◽  
Vol 4 (4) ◽  
pp. 155892500900400
Author(s):  
Jaakko Larkomaa ◽  
Jouko Niinimäki ◽  
Markus Honkanen ◽  
Muhammad Hanif ◽  
Pentti Saarenrinne
Keyword(s):  
Three Dimensional ◽  
Fibre Properties ◽  
Before And After ◽  
Dimensional Shape ◽  
Fractionation Method ◽  
Pulp Properties ◽  
Cellulosic Fibres ◽  
Three Dimensional Shape ◽  
Consistency Evaluation ◽  
Recognition Technique

This paper investigates a fractionation method of cellulosic fibres in dry state. Although processing of cellulosic fibres in airstream has been utilised for decades in airlaid processes, no attempts to fractionate fibres in dry state have been reported. Our main goal is to determine how fibre properties and fibre consistency affect fibre flocculation and thus the behaviour of fibres in fractionation. Also evaluations of quality and capacity of fractionation operation are made. Pulp flocculation behaviour is measured with digital imaging and image recognition technique before and after the fractionation device. A doubleview, orthogonal imaging approach is applied obtaining statistics of three-dimensional shape, dimensions and coordinates of detected fibre flocs. Fraction and fibre properties are determined with Metso Fractionator and Metso Fiberlab. Results show that fibre behaviour in a given system strongly depends on the pulp properties. Flocculation was found to be strongly dependent on fibre consistency. Evaluation of fractionation operation was done with help of calculations of mass-reject rates and separation efficiencies. Calculations showed that highest separation efficiencies can be achieved with system when mass-reject rate is between 0.30 and 0.40.

The effects of initial spacing on wood density, fibre and pulp properties in jack pine (Pinus banksiana Lamb.)

Holzforschung ◽  
2004 ◽  
Vol 58 (5) ◽  
pp. 455-463 ◽  
Author(s):  
Kyu-Young Kang ◽  
Shu Y. Zhang ◽  
Shawn D. Mansfield
Keyword(s):  
Forest Management ◽  
Wood Density ◽  
Pinus Banksiana ◽  
Management Practices ◽  
Jack Pine ◽  
Fibre Properties ◽  
Commercial Thinning ◽  
Initial Spacing ◽  
Pulp Properties ◽  
The Impact

Abstract Relationships between basic tree and wood properties, and species, seed source, geographic location, site conditions and management decisions are very complex. The objective of this study was to quantify the effects of forest management practices on wood density, fibre and pulp properties in jack pine, one of the most important commercial species in Northern America. A better understanding of the relationship between initial spacing and wood and end-product quality should help define improved forest management strategies required to produce quality wood and products in the future. On the basis of the oldest jack pine initial spacing trial established in 1941 by the USDA Forest Service, this study examined the impact of four different initial spacing trials on tree growth, wood density, fibre and pulp properties of jack pine. The results clearly show that initial stand spacing has a significant effect on all of these properties, and thus it is possible to improve yield and wood and pulp fibre properties of jack pine through stand density regulation. Additionally, a positive effect of pre-commercial thinning on fibre properties was also demonstrated. As a consequence of these results, basic prescription information for decision-making in the establishment of jack pine plantations with desirable pulp properties can be elucidated.

A Device for Magnification Measurement

1972 ◽  
Vol 30 ◽  
pp. 622-623
Author(s):  
J.A. Eades ◽  
A. van Dun
Keyword(s):  
Electron Microscope ◽  
Small Displacement ◽  
Private Communication ◽  
Piezoelectric Crystal ◽  
Double Exposure ◽  
Standard Methods ◽  
Elegant Method ◽  
The Right ◽  
Piezo Electric

The measurement of magnification in the electron microscope is always troublesome especially when a goniometer stage is in use, since there can be wide variations from calibrated values. One elegant method (L.M.Brown, private communication) of avoiding the difficulties of standard methods would be to fit a device which displaces the specimen a small but known distance and recording the displacement by a double exposure. Such a device would obviate the need for changing the specimen and guarantee that the magnification was measured under precisely the conditions used.Such a small displacement could be produced by any suitable transducer mounted in one of the specimen translation mechanisms. In the present case a piezoelectric crystal was used. Modern synthetic piezo electric ceramics readily give reproducible displacements in the right range for quite modest voltages (for example: Joyce and Wilson, 1969).

Comprehensive evaluation of kraft pulp properties from fast-growing woods

TAPPI Journal ◽  
2010 ◽  
Vol 9 (6) ◽  
pp. 34-39
Author(s):  
AIYU QU ◽  
YANHUI AO ◽  
JUN YAN ◽  
GUIGAN FANG
Keyword(s):  
Kraft Pulp ◽  
Comprehensive Evaluation ◽  
Evaluation Model ◽  
Evaluation Index System ◽  
Evaluation Index ◽  
Wood Cellulose ◽  
Fuzzy Matrix ◽  
Fast Growing ◽  
Pulp Properties ◽  
Evaluation Index Systems

To develop new wood cellulose resources and fast-growing pulpwood plantation fiber sources, it is very important to evaluate their pulping properties. A comprehensive multi-index pulping-suitability evaluation model is investigated in this paper by considering four fast-growing wood species. First, a new evaluation-index system for kraft pulp was developed based on traditional evaluation-index systems. Then, the membership degree of every index was analyzed to obtain a fuzzy matrix. The proportional contribution of each parameter to the main pulping properties could then be determined. Finally, a comprehensive evaluation model of kraft pulp properties was developed. The model is reliable compared with traditional assessment methods. The results confirmed the feasibility and rationality of developing new wood cellulose resources and fast-growing pulpwood plantations using fuzzy comprehensive evaluations.

Refining Energy Reduction and Pulp Characteristic Modification of Alkaline Peroxide Mechanical Pulp (APMP) Through Enzyme Application

TAPPI Journal ◽  
2009 ◽  
Vol 8 (5) ◽  
pp. 19-25 ◽  
Author(s):  
PETER W. HART ◽  
DARRELL M. WAITE ◽  
LUC THIBAULT, ◽  
JOHN TOMASHEK ◽  
MARIE-EVE ROUSSEAU ◽  
...  
Keyword(s):  
Wood Chip ◽  
The United States ◽  
Enzyme Treatment ◽  
Chemical Application ◽  
Alkaline Peroxide ◽  
Eucalyptus Wood ◽  
Pulp Properties ◽  
Pulp Processing ◽  
Two Stages ◽  
Enzyme Application

Eucalyptus wood chips were subjected to impregnation with various blends of novel fiber modify-ing enzymes before chemical pretreatment and two stages of refining using the preconditioning refiner chemical–alkaline peroxide mechanical pulping (PRC-APMP) process. Wood chip impregnation and pulp processing was con-ducted at a pilot plant in the United States. When compared under constant chemical application and at a constant 350 mL CSF, enzyme treatment reduced specific refining energy by at least 24%. The effect of one versus two stages of impregnation and of enzyme action upon several physical pulp properties was determined.

Does the kappa number method accurately reflect lignin content in nonwood pulps?

TAPPI Journal ◽  
2018 ◽  
Vol 17 (11) ◽  
pp. 611-617
Author(s):  
Sabrina Burkhardt
Keyword(s):  
Lignin Content ◽  
Paper Industry ◽  
Pulp And Paper Industry ◽  
Original Data ◽  
Kappa Number ◽  
Klason Lignin ◽  
Organic Functional Groups ◽  
Pulp Properties ◽  
Wood Pulps ◽  
Hexenuronic Acid

The traditional kappa number method was developed in 1960 as a way to more quickly determine the level of lignin remaining in a completed or in-progress pulp. A significantly faster approach than the Klason lignin procedure, the kappa number method is based on the reaction of a strong oxidizing agent (KMnO4) with lignin and small amounts of other organic functional groups present in the pulp, such as hexenuronic acid. While the usefulness of the kappa number for providing information about bleaching requirements and pulp properties has arguably transformed the pulp and paper industry, it has been mostly developed for kraft, sulfite, and soda wood pulps. Nonwood species have a different chemical makeup than hardwood or softwood sources. These chemical differ-ences can influence kappa and Klason measurements on the pulp and lead to wide ranges of error. Both original data from Sustainable Fiber Technologies’ sulfur and chlorine-free pulping process and kappa and Klason data from various nonwood pulp literature sources will be presented to challenge the assumption that the kappa number accurately represents lignin content in nonwood pulps.

Resonant-type MEMS Magnetic Sensor with FePd Magneto-strictive and PZT Piezo-electric Films

2019 ◽  
Vol 139 (11) ◽  
pp. 383-384
Author(s):  
Naoki Okada ◽  
Koudai Suzuki ◽  
Takashi Mineta
Keyword(s):  
Magnetic Sensor ◽  
Piezo Electric

scholarly journals Non-Wood Fibers: Relationships of Fiber Properties with Pulp Properties

ACS Omega ◽  
2021 ◽  
Author(s):  
Taslima Ferdous ◽  
Yonghao Ni ◽  
Mohammad Abdul Quaiyyum ◽  
Mohammad Nashir Uddin ◽  
Md Sarwar Jahan
Keyword(s):  
Wood Fibers ◽  
Fiber Properties ◽  
Pulp Properties

scholarly journals All-Fiber Pyro- and Piezo-electric Nanogenerator for IoT Based Self-Powered Health-Care Monitoring

2021 ◽  
Author(s):  
Biswajit Mahanty ◽  
Sujoy Kumar Ghosh ◽  
Kuntal Maity ◽  
KRITTISH ROY ◽  
Subrata Sarkar ◽  
...  
Keyword(s):  
Health Care ◽  
Carbon Nanotube ◽  
Vinylidene Fluoride ◽  
Electrospun Nanofibers ◽  
Multiwall Carbon Nanotube ◽  
Poly Vinylidene Fluoride ◽  
Self Powered ◽  
Health Care Monitoring ◽  
Multiwall Carbon ◽  
Piezo Electric

In this work, an all-fiber pyro- and piezo-electric nanogenerator (PPNG) is designed by multiwall carbon nanotube (MWCNT) doped poly(vinylidene fluoride) (PVDF) electrospun nanofibers as the active layer and interlocked conducting...

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