Abstract

Recentadvances in the development of the Acetosolv process, particularly with respect to its industrial scale-up are presented. The main drawback that makes the process economically unfeasible up to now is its highprocess energy demand, which is determined by: (1) liquid flows required in the digestion, separation of dissolved lignin and hemicelluloses, and washing of acetic pulp, and (2) the amount of water fed into the distillation column. A continuous Acetosolv process was developed, in order to decrease the required liquid/solid ratio. In addition, pulp washing by ethyl acetate rather than by water and drying of the digestion liquor has been proposed to minimize the water feed in the distillation column. The processes under study have been modeled in ASPEN PLUS to calculate the mass balance of each subsystem and the energy requirement of principle subsystems, as well as of the overall process. The overall energy requirement was reduced dramatically.