초록 ▼

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 consu

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.

대표청구항 ▼

A method of intensifying washing of a fiber suspension after digestion, said suspension containing residual alkali in a way so as to preserve the strength properties of fibers in said fiber suspension so that they are the same before washing and after washing, comprising the steps of: maintaining th

A method of intensifying washing of a fiber suspension after digestion, said suspension containing residual alkali in a way so as to preserve the strength properties of fibers in said fiber suspension so that they are the same before washing and after washing, comprising the steps of: maintaining the consistency of said pulp suspension throughout the method at a high consistency range of 3-30%; prewashing said pulp suspension in a pressurized washer, said pulp suspension is prewashed with a hot aqueous washing liquor sufficient for reducing the alkali concentration to no more than 5 g/l and raising the temperature of the pulp suspension above 100°C.