THERMOPULP(R) - A NEW ENERGY-EFFICIENT ME CHANICAL PULPING PROCESS

A new two-stage refiner mechanical pulping system, referred to as Ther mopulp(R), is presented, where the well-known reduction of energy to r upture in the wood structure at a temperature well above the softening point of lignin has been utilized to reduce the energy in the product ion of mechanical pulp for printing grades. The energy consumption in mill scale refining to produce news quality pulp has been reduced by a bout 20% compared to the reference system, which consists of a two-sta ge double disc TMP system, is already considered to be an energy effic ient system, producing TMP at 150 ml CSF at a specific energy consumpt ion of 1650 kWh/t. The quality of the pulp from the Thermopulp process is equivalent to that of the reference pulp with the exception of a s mall reduction in brightness and also tear index. Extending the raw ma terial reference base, Thermopulp pilot plant trials have also been ca rried out on Pinus taeda and Pinus radiata with encouraging results. T he earlier observations on Spruce concerning improved density at a giv en freeness level were more pronounced in the case ct the pine species .