Influence of temperature on energy efficiency in double disc chip refining

• In 2008 Holmen Paper Braviken invested in a new TMP-line. The primary stage refining system of pressurized counter-rotating double disc chip refiners in this TMP line has been investigated. The aim of this work was to improve the energy efficiency through optimization of the refining temperature.The specific refining energy was varied at different refining temperatures. Inlet and housing pressures were used to control temperature. There was no pressure difference between inlet and housing pressure.An increased inlet- and housing pressure (from 4.6 up to 7.1 bar(g)) and thereby refining temperature resulted in a reduction of the energy consumption to same tensile index by 80-150 kWh/adt. The largest energy reduction was attained at low refining energy levels. An increase in energy efficiency may be explained by a decrease in plate gap, probably caused by softer fibre pad and lower steam volume. At constant specific refining energy and elevated temperature, the tensile index and light scattering coefficients were higher, shives content and average fibre length were lower. These results are probably due to the increased intensity resulting from the plate gap reduction.Increased refining pressure proved to have a positive effect on energy efficiency and pulp quality in a long term trial, i.e. throughout a plate-life.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Kemiteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Chemical Engineering (hsv//eng)

Nyckelord

TMP; energy efficiency; Temperature; Pressure; Double disc refining; Segment wear; Pulp quality

Chemical engineering

Kemiteknik

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)