Evaluation of a Laboratory Simulation Chain for Papermaking SubProcesses
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Helsinki University of Technology |
Diplomityö
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Date
2005
Department
Major/Subject
Paperitekniikka
Mcode
Puu-21
Degree programme
Language
en
Pages
ii + 112 s. + liitt. 14
Series
Abstract
The objective of the study is to evaluate and validate an innovated laboratory simulation system for papermaking unit operations with new devices that possibly generate more realistic conditions. The results of the simulation are compared with the results from the laboratory standard test and a pilot trial in Paper Technology Laboratory Helsinki University of Technology. The Voith LR40 refining station, with the ability to control the refining intensity and refining energy, is used. In the sheet forming step, the Moving Belt Former (MBF), generating high pulsation with high vacuum during dewatering, is used to produce sheets for further tests. Wet pressing is simulated by using a universal material testing frame MTS810 which provides short press pulses in a millisecond scale with a maximum load of 100kN. The AND IR moisture analyser is used for drying studies. The EP-210 laboratory calendar is used after drying. The MBF is able to characterize the properties of furnishes with the vacuum drainage curves. The highly refined chemical pulps and high fine amount of TMP have better higher vacuum curve due to the dense web. In the pressing condition in this work, inlet dry solid content is the more determinant factor of outlet dry solid content after a pressing than the pressing load and residence time. The drying studies conducted using the IR moisture analyser, resulted in varying drying properties of the sheets after pressing depending on the refining intensity and the sheet forming manner. It is found that the pressing load and residence time have different roles in terms of web densification with chemical pulps and TMP. The pressing load is more important for the densification with chemical pulps than the residence time. The pressing time, however, has an important role for densification with TMP. The effect of washing off TMP fines is visible in the opacity and light scattering coefficient with the sheets produced with MBF. The formation has a more important role than the density for the tensile strength due to the lower formation quality of the sheets made by MBF.Description
Supervisor
Paulapuro, HannuThesis advisor
Paltakari, JouniKeywords
simulation, simulointi, Voith LR40 refining station, laboratorion kalanteri, Moving Belt Former (MBF), MTS-810, moisture analyzer, laboratory calender