DISPLACEMENT HEATING IN CONTINUOUS DIGESTERS

摘要

An apparatus and method for treating cellulosic wood chips in a digestion process for the liberation of pulp in a caustic hydroxide solution at high pressures and temperatures by delivering preconditioned wood chips to a first chamber (10) and circulating a low temperature black liquor through the chamber (10) to preheat the chips, while continuously feeding the chips through the chamber (10) to a second chamber (21) at high temperature and pressure, circulating high temperature black liquor to the chips in the second chamber (21) to advance them to cooking temperature, feeding white liquor and the chips to a digester (33) for the digestion process over a predetermined period of time, and removing digested pulp and delivering the pulp to a washer with the black liquor for washing being utilized for the first chamber (10), and heating the white liquor through a heat exchange process with the high temperature black liquor.