The first systems for production of

The first systems for production of mechanical pulps from chips in a refiner were developed during the 1930’s by Arne Asplund. In the Asplund process, wood chips are refined in pressurised systems at temperatures well above the softening temperature of the lignin. The pulp is used for fibreboard manufacturing. Not until the end of 1950 successful trials were made with refiner pulps for papermaking. The pulp was made in atmospheric refiners in a system without pre-treatment of the chips with steam and was called RMP (Refiner Mechanical Pulp). The development of the technology for refiner pulps for printing paper production picked up speed during the 1960’s when the principles for the present processes for production of TMP (Thermo-Mechanical Pulp) started to take shape. In the TMP-process the chips are preheated and refined in a steam pressurised system