SAETT OCH Utrustning VID KONTINUERLIG CELLULOSAKOKNING.

摘要

A method in connection with continuous pulp cooking to wash the delignified pulp in a vertical, elongated pressure vessel comprising a cooking zone (1), a main washing zone (3) and a conditioning zone (4) at the bottom of the vessel, where the pulp is further washed and optionally diluted and cooled, said cooking zone being separated from said main washing zone by an interruption zone (2), where diluting/washing liquid displaces the cooking liquor, which is drained via one or several interruption circulation screen girdles (5), while contaminated washing liquid in the conditioning zone is displaced by cleaner washing liquid and is drained via one or several bottom screen girdles (10). At least part of that washing liquid which has been drained through the bottom screen girdle/s/ (10) is passed in counter-current to, but not through, the pulp, i.e. not in contact with the pulp, but through at least one separate counter-current conduit (17) up to at least one intermediate screening stage (14) between the interruption zone and the conditioning zone, where it enters the pulp centrally and spreads outwards to displace contaminated diluting/washing liquid, which is drained through one or several intermediate screen girdles (15).