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
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Penttinen, K
[1]
- Lappeenranta Univ. of Technology, Lappeenranta (Finland)
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}
}
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}
}