FORFARANDE FOR EFFEKTIVERING AV FIBERSUSPENSIONSTVETT

摘要

The present invention relates to a method of intensifying the washing of a fiber suspension. In particular, the present invention relates to decreasing the lignin content of a fiber suspension by extracting. Lignin removal is usually carried out at a consistency of less than 3% whereby heating consumes much energy. The method of the invention allows a considerable increase in the consistency of the suspension which results in that the energy consumption is decreased to a fraction of the one required by prior art methods. A characteristic feature of the method of the invention is that dry substance and chemicals contained in the fibers are extracted at a raised pressure and temperature.