Dryness and physical properties of paper webs in laboratory-scale impulse processing
2001 (English)In: Drying Technology, ISSN 0737-3937, E-ISSN 1532-2300, Vol. 19, no 10, p. 2435-2450Article in journal (Refereed) Published
Abstract [en]
This investigation evaluates the changes in dryness and physical properties of impulse processed paper webs. A laboratory-scale platen press was used to process 60 g/m2 webs under a wide range of pressure impulses and temperatures (23-380°C). The heat transfer rate to the web was also varied by using two different platen materials (steel and copper). Both thermomechanical and bleached kraft pulps were tested, and the dryness, density, surface roughness, and Scott bond were measured for each trial. Results show that dewatering is enhanced with increased temperature, pressure, and nip residence time, while pressure pulse shape and platen material have little influence. An empirical correlation is given to relate sheet dryness to the key process variables. This correlation suggests that resulting dryness values are not unique; that is, different combinations of temperature, pressure, and nip residence time can be used to obtain a similar level of dryness. Physical reasoning was used to develop a second correlation that links the resulting dryness to the density of the completely dried web. Surface roughness decreased with increasing surface temperature, while Scott bond rose sharply under conditions of high temperature and long nip residence time.
Place, publisher, year, edition, pages
2001. Vol. 19, no 10, p. 2435-2450
Keywords [en]
Correlations, Experimental, Impulse drying, Pressing, Water removal, Bleached pulp, Dewatering, Drying, Heat transfer, Kraft pulp, Presses (machine tools), Pressure effects, Surface roughness, Thermal effects, Thermomechanical pulp, Scott bonds, Papermaking, liquid-solid separation, pulp and paper industry, Bleached Pulps, Kraft Pulps, Paper Making, Paper Webs, Thermomechanical Pulps
National Category
Materials Engineering
Identifiers
URN: urn:nbn:se:ri:diva-73645DOI: 10.1081/DRT-100108247Scopus ID: 2-s2.0-0035520215OAI: oai:DiVA.org:ri-73645DiVA, id: diva2:1874991
2024-06-202024-06-202024-06-20Bibliographically approved