Power consumption distribution in a TMP refiner:: comparison of the first and second stages

Wood chips are broken rapidly into coarse pulp in the breaking zone in the feed of a first stage TMP refiner. In a second stage refiner the breaking zone is removed, because the feed is coarse pulp discharged from the first stage refiner. We studied the power consumption in a second stage refiner and calculated the power consumption distribution for the first and second stages. The results show that the power consumption in a second stage refiner increases along the radius, while in a first-stage refiner, the distribution is more even. The innermost part of the second stage refiner seemed to work with a very low energy consumption, compared with the outer parts.