| 1. |
- Alam, Anzar, et al.
(författare)
-
Online surface characterization of paper and paperboards in a wide-range of the spatial wavelength spectrum
- 2012
-
Ingår i: Applied Surface Science. - : Elsevier BV. - 0169-4332 .- 1873-5584. ; 258:20, s. 7928-7935
-
Tidskriftsartikel (refereegranskat)abstract
- In the paper industry, surface topography is the essence of both paper and paperboard, and accurate topographical measurements are equally essential in order to achieve a uniform smooth surface. The traditional laboratory methods measure only a few samples from the entire tambour and there are other obvious limitations to this approach. Online measurements may be of significant value to improve the surface quality throughout the production. Roughness is one of the topography components and the majority of techniques measure paper by means of a single predictor of average roughness, R a which is inadequate in providing a comprehensive characterization of the surface. Measurements, in a wide range ofwavelengths, can characterize topography components such as roughness, waviness, cockling, etc. Online measurements were taken for various grades of 8 paper reels, containing the wireside and topsides for newspaper, and uncoated and coated sides of paperboards. Their surfacecharacterization, in the spatial wavelength spectrum, from 0.1 to 10 mm was obtained. This article presents the online characterizationresults which have efficiently distinguished the surfaces of same family materials including the edge and the middle position reels of fine coatedpaperboard. Online measurements were taken, at Iggesund Paperboard Pilot Coater in Sweden, by using a recently developed OnlineTopography (OnTop) device which is based on the principle of light triangulation. © 2012 Elsevier B.V. All rights reserved.
|
|
| 2. |
- Alam, Anzar, et al.
(författare)
-
Online surface roughness characterization of paper and paperboard using a line of light triangulation technique
- 2012
-
Ingår i: Nordic Pulp & Paper Research Journal. - 0283-2631 .- 2000-0669. ; 27:3, s. 662-670
-
Tidskriftsartikel (refereegranskat)abstract
- Within both the paper and paperboard industries, real time monitoring and measurement of surface roughness of a paper moving at high velocities is an important and challenging area of research. The uniform surface, for an entire production, can be effectively achieved by monitoring and controlling the paper surface roughness, in real time during the manufacturing steps. Presently the majority of paper industries rely on traditional laboratory profilometers. The obvious limitations of lab profilometers are that these are slow, do not measure the quality of entire reels but rather deal with only a few small pieces of samples taken from the end of the reels and it is difficult to make any possible correction in the productionlines without knowing the online roughness data. To eradicate the disadvantages associated with conventional measurements, an online prototype instrument has been developed that measures the surface roughness during the manufacturing steps, and is based on a line of lighttriangulation technique. The prototype technique will be of assistance in ensuring tight process control in order to maintain both a better and auniform quality throughout the entire production. It measures the whole reel, meter by meter, in traditional units of roughness and is also capable of characterizing the topography in a wide range of wavelength spectra. The article presents the online analyses results obtained from the developed prototype. The real time measurements, in a paperboard pilot mill, have successfully characterized and distinguished 16 different grades of newspaper and paperboard reels including reels which have the same family of quality grades and materials.
|
|
| 3. |
- Alam, Mohammad Anzar, et al.
(författare)
-
Investigation of the surface topographical differences between the Cross Direction and the Machine Direction for newspaper and paperboard
- 2011
-
Ingår i: Nordic Pulp & Paper Research Journal. - 0283-2631 .- 2000-0669. ; 26:4, s. 468-475
-
Tidskriftsartikel (refereegranskat)abstract
- Paper and paperboard surface quality is constantly being improved by the industry. This improvement work deals with the essential fact that the surface topography must be measured, both in relation to offline and online measurements for the manufactured products. Most measurements relating to surface topography (especially online) are performed either in the machine direction (MD) or in the cross direction (CD). It has been the opinion of SCA Ortviken AB and Iggesund Paperboard AB that the surface topography amplitudes are almost always higher in the CD than in the MD, for their products which consist of newspaper and paperboard. This article aims to investigate the rela-tionship between the CD and the MD surface topography amplitudes for a wide range of spatial wavelength for both newspaper and paperboard. The tests and investiga-tions have been conducted using an FRT Microprof profilometer within the range 20 μm up to 8 mm, and the results confirm that the surface topography amplitudes are higher in the CD for most of the shorter spatial wavelength within this range. The results also show significant differences between measurements for different paper qualities, suggesting a requirement to investigate the relationship between the CD and the MD topography for all paper and paperboard qualities of interest for a paper or paperboard mill, before a decision is made in relation to a measurement method.
|
|
| 4. |
- Engstrand, Per, 1955-, et al.
(författare)
-
Improved refining energy efficiency in thermo-mechanical pulping by means of collimated wood chipping – from solid mechanics to full scale evaluation
- 2016
-
Ingår i: PaperWeek Canada 2016 Conference <em>February 1 to 5, 2016, Montreal</em>.
-
Konferensbidrag (refereegranskat)abstract
- The wood chipping process was never optimized with regard to high yield pulping processes as thermomechanical pulping (TMP) and chemithermomechanical pulping (CTMP). It is generally believed that wood chips for pulping should be produced in such a way that the degree of damage is minimized and that the chip dimensional distribution should be as narrow as possible. Since the TMP and CTMP processes were developed in the 60-ies and 70-ies, compression screw as well as roll nip equipment have been developed to pretreat wood chips as a way to reduce refining energy consumption to given fiber and pulp properties and also in order to improve impregnation. The general conclusions are that a combination of shear and compression in the tangential or radial direction of the wood initiates cracks that later in the refiner will enhance and optimize fiber separation and also fiber property development. The idea with the collimated chipping technology is to utilize the wood chipper as a tool, combining cutting of wood logs to wood chips with a pretreatment of the chips by creating cracks that would enhance fiber separation, fiber surface development as well as chip-impregnation. In this case the compression is performed in the wood fiber direction, in which direction wood actually is weakest when it comes to compression induced cracking. The maximization of the amount of cracks in wood-chips is performed by optimizing the knife angle (or spout angle) in the chipper, to what we call collimated chipping (according to a patent owned by CCT AB). This presentation describes a theoretical background and two demonstration scale studies performed by SCA Forest Products at their Ortviken mill. One conclusion drawn, based on two-month test period with three weeks of collimated chipping, was that specific refining energy reduction was around 100 kWh/adt of the 1400 kWh/adt used in primary stage double disc refining. Most probably the potential is higher if the whole system is optimized. Tests were performed at constant production rate and energy was reduced by reducing power to constant freeness, leading to similar tensile and light scattering levels. The deliberately increased forces created in the wood chipper by means of an optimized (increased) edge angle caused more problems with knife holder equipment than normally, as well as increased vibrations. These problems will have to be solved for future long-term implementation of the technique.
|
|
| 5. |
|
|
| 6. |
|
|
| 7. |
- Lidén, Joar, et al.
(författare)
-
Quality control of single stage refining in a double disc plant
- 2003
-
Ingår i: 2003 International Mechanical Pulping Conference, Jun 2-5 2003, Quebec City, Que., Canada. - 1896742866 ; , s. 239-244
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The SCA Ortviken mill in Mid Sweden has capacity to produce 2150 adtpd of TMP at CSF=150 ml in 60" double disc refiners in a single stage operation. The objective of this paper is to present models for CSF and long fibre content control in the refining process and to show the results with and without the control system. The control system is model-based. Results showed better CSF control with the application. The variability reduction was 50%.
|
|
