Patent ID: 8647469
Filing Date: 2014-02-11
Classification: D21C

Abstract:
1. A method for the impregnation and steaming of chips during the manufacture of chemical pulp, comprising; continuously feeding chips without preceding steam treatment to a top of an impregnation vessel, adding hot impregnation fluid (BL) at a first temperature above a boiling point of the hot impregnation fluid to the impregnation vessel, the hot impregnation fluid being added via a pipe having an outlet end located below a chip level (CH the added hot impregnation fluid (BL) establishing a fluid level (LIQ establishing a pressure at the top of the impregnation vessel that is essentially at atmospheric pressure, ±0.5 bar(g), withdrawing a first impregnation fluid (REC) for a first use from a first withdrawal volume located at about the fluid level (LIQ withdrawing a second impregnation fluid from a second withdrawal volume located behind a second screen row located a distance below the first screen row and mounted in the wall of the impregnation vessel, the distance below the first screen row not exceeding a diameter of the impregnation vessel, returning at least a part of the second impregnation fluid via the pipe into a center of the impregnation vessel, and feeding out impregnated chips from a bottom of the impregnation vessel.