摘要 |
<p>Method and apparatus for treatment of comminuted fibre material before chemical digestion of the material, whereby the material (a) in a first step is heated, preferably by addition of steam, in a gas atmosphere with a pressure (P1) and a temperature (T1), (b) in a second step has air extracted from it, in a gas atmosphere with a pressure (P2) and a temperature (T2), where (T1) > (T2) and (P2) is sufficiently lower than (P1) in order to extract air from the material, (c) in a third step is soaked in impregnation liquid, whereby said first step (a) is performed in a first space (1, 2, 1a) and said second step (b) is performed in a second space (3, 1b). The material is added to this second space in such a way that it is exposed to a lowering in the pressure, when it is transferred from the first space to the second space. Said impregnation liquid with a temperature (T3) is added to said material in sequentially direct connection to a retention time in the gas atmosphere (P2, T2) in said second space.</p> |