| 摘要 |
The invention relates to a system and a process for the oxygen delignification of pulp consisting of lignocellulose-containing material whose mean concentration is 8-18% pulp consistency, in at least two stages. The invention is characterized in that the oxygen delignification takes place in a first stage with a short dwell time of approx. 3-6 minutes, at a low temperature of approx. 85.degree.C and under a low pressure of approx. 0-4 bar, followed by a concluding stage with a longer dwell time of approx. 50-90 minutes, at a higher temperature of approx. 100.degree.C and under a higher pressure of approx. 8-10 bar. This makes it possible, in an industrial process, to exploit the kinetics of the oxygen delignification in an optimal manner for the purpose of obtaining a selective oxygen delignification at low installation cost and at low operating cost.
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