Dewatering of high-moisture wood chips by roller compression method

In seeking an efficient method for drying very wet chips, we developed and tested an original continuous dewatering system using mechanical compression (10-30 MPa). The moisture content of cedar chips decreased from 100-270% to 85-130% (dry basis), and the energy required to remove the water was 9% (power consumption basis) and 25% (primary energy basis) for heat energy to evaporate the water. In the case of combined drying, in which roller compression was applied first, followed by thermal drying, the energy required to dry wet cedar chips to a moisture content as low as 20% was 49% (power consumption basis) and 58% (primary energy basis) of that required for thermal heating alone. These results indicate that the combined method uses less energy to dry very wet wood chips.