Process for increasing the solids content of black liquour at its recovery in a sulfate pulping process

摘要

The invention relates to a process of increasing the solids content of black liquor at its recovery in a sulfate pulping process. According to the invention, the liquor is first heated at a pressure which is so high that no boiling occurs at the heating temperature, after which the liquor is led to a tank where its pressure is released to a value below the saturation pressure of steam at the relative temperature of the liquor such that water is evaporated. The liquor thus concentrated can be led to the liquor combustion in the recovery process.