摘要 |
A vapor phase continuous digester system and method for producing paper pulp from comminuted cellulosic fibrous material take into account the level of dissolved organic materials (DOM), such as lignin, hemi-cellulose, and cellulose, throughout the cook (particularly kraft cook). In the vapor phase digester, the level of liquid at the top of the digester is more precisely controlled by circulating some of the withdrawn liquid from a circulatory loop of the digester to a level tank associated with the feed system. An in-line drainer may be provided in the feed system between a make-up liquor pump and a liquid inlet conduit leading to the top of an impregnation vessel. Within the digester, a set of extraction/dilution screens is provided specifically positioned and spaced from each other, and with respect to a reintroduction conduit opening, so that mixing of different DOM concentration liquids is minimized.
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