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Refining combined with screening. Final report; Lajitteleva jauhatus; Loppuraportti

Technical Report:

Abstract

The aim was to investigate a new refiner design and its suitability for mechanical pulp production. A small-scale prototype refiner was built incorporating both defibration and screening, the aim being to reduce energy consumption. A feature of the refiner is its built-in screening plate. The prototype allowed the use of different rotors and screening plates. It was also possible to alter the structure of the refiner to some extent. The characteristics of the pulp produced with the prototype were comparable with those of pulps from open refining (RMP). The tear index was 4-5 mNm{sup 2}/g and tensile index 50-60 Nm/g. The tensile index was 2-3 times higher than that of RMP or TMP, presumably because of the high fines content, which is known to raise tensile index. For the same reason, the light-scattering coefficient was also high (50-70 %). Treating the pulp with chemical before refining reduced the light-scattering coefficient to about 43 %. Pulp brightness was generally 52-56 %, which can be considered reasonable. Chemical pretreatment reduced brightness to about 40 %. The pulp shives content, determined on a 0.15 mm Somerville screen, was less than 0.1 % at best. In trial runs with a 0.15 mm refiner screen  More>>
Authors:
Penttinen, K [1] 
  1. Lappeenranta Univ. of Technology, Lappeenranta (Finland)
Publication Date:
Oct 01, 1993
Product Type:
Technical Report
Report Number:
KCL-KUITU-27
Reference Number:
SCA: 320303; PA: FI-93:003304; EDB-94:013019; NTS-94:007761; ERA-19:004309; SN: 93001063845
Resource Relation:
Other Information: DN: FIBRE Research Programme; PBD: 1993
Subject:
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION; PAPER INDUSTRY; REFINING; ENERGY CONSERVATION; WOOD; SCREENS; ENERGY CONSUMPTION; PROCESS DEVELOPMENT UNITS; SORTING; SLURRIES; OPTICAL PROPERTIES; TENSILE PROPERTIES; 320303; EQUIPMENT AND PROCESSES
OSTI ID:
10111540
Research Organizations:
Finnish Pulp and Paper Research Inst., Espoo (Finland)
Country of Origin:
Finland
Language:
Finnish
Other Identifying Numbers:
Other: ON: DE94702102; TRN: FI9303304
Availability:
OSTI; NTIS
Submitting Site:
FI
Size:
44 p.
Announcement Date:
Jun 30, 2005

Technical Report:

Citation Formats

Penttinen, K. Refining combined with screening. Final report; Lajitteleva jauhatus; Loppuraportti. Finland: N. p., 1993. Web.
Penttinen, K. Refining combined with screening. Final report; Lajitteleva jauhatus; Loppuraportti. Finland.
Penttinen, K. 1993. "Refining combined with screening. Final report; Lajitteleva jauhatus; Loppuraportti." Finland.
@misc{etde_10111540,
title = {Refining combined with screening. Final report; Lajitteleva jauhatus; Loppuraportti}
author = {Penttinen, K}
abstractNote = {The aim was to investigate a new refiner design and its suitability for mechanical pulp production. A small-scale prototype refiner was built incorporating both defibration and screening, the aim being to reduce energy consumption. A feature of the refiner is its built-in screening plate. The prototype allowed the use of different rotors and screening plates. It was also possible to alter the structure of the refiner to some extent. The characteristics of the pulp produced with the prototype were comparable with those of pulps from open refining (RMP). The tear index was 4-5 mNm{sup 2}/g and tensile index 50-60 Nm/g. The tensile index was 2-3 times higher than that of RMP or TMP, presumably because of the high fines content, which is known to raise tensile index. For the same reason, the light-scattering coefficient was also high (50-70 %). Treating the pulp with chemical before refining reduced the light-scattering coefficient to about 43 %. Pulp brightness was generally 52-56 %, which can be considered reasonable. Chemical pretreatment reduced brightness to about 40 %. The pulp shives content, determined on a 0.15 mm Somerville screen, was less than 0.1 % at best. In trial runs with a 0.15 mm refiner screen plate the shives content was as low as 0.03 %. The refiner tended to produce a lot of fines, resulting in freeness values of 5-20 ml. Energy consumption was fairly high, but has been considerably reduced by further developing the refiner. At its best, energy consumption is now equivalent to that in conventional RMP production. At present energy is being wasted because the fibres are being over-refined, and there is thus potential for improvement in this respect. Chemical pretreatment had positive impact on energy consumption}
place = {Finland}
year = {1993}
month = {Oct}
}