Patent ID: 6086712
Filing Date: 2000-07-11
Classification: D21C,D21G

Abstract:
A method of kraft cooking cellulose pulp using a batch digester capable of producing at least eight tons of cellulose pulp per day, the digester having a screen and a recirculation line for withdrawing liquor from the screen and reintroducing liquor to the batch digester at a different level than the screen, said method comprising:(a) kraft cooking at least eight tons of pulp per day in the batch digester; and(b) treating the liquor in the recirculation line to effectively significantly reduce the dissolved organic material concentration thereof, including each of lignin, hemicellulose, and cellulose, by at least one of dilution, extraction and dilution, absorption, precipitation, filtration, destruction, gravity separation, super critical extraction, and evaporation.