METHOD AND SYSTEM FOR DIRECT CONTACT OF HOT ALKALINE SOLUTION WITH WOOD CHIPS WHEN CIRCULATING TRANSFER Russian patent published in 2012 - IPC D21C3/24 D21C7/00 

FIELD: textiles, paper.

SUBSTANCE: suspension of wood chips is heated in an alkaline digestion system comprising impregnating boiler and a boiler of chemical cooking. Chips are impregnated with alkali liquor in an impregnating boiler. Wood chips are transported from the impregnating boiler to the top level of the cooking boiler. Alkali liquor is removed from the washing sieve of the lower level of the cooking boiler, where the extracted liquor has a temperature substantially higher than the temperature of wood chips in the impregnating boiler. The first part of the liquor extracted from the lower level of the cooking boiler is added to the chips to be transported or transported from the impregnating boiler to the cooking boiler and the transported wood chips are heated with heat energy of the extracted liquor. The second part of the liquor extracted from the washing sieve of the low level is transported to the upper part of the cooking boiler.

EFFECT: invention provides a recycling of heat from the excess of the black liquor extracted from the lower sets of sieves, or from the lowest set of sieves of the cooking boiler for heating the black liquor in the circulation line of suspended chips between the upper part and the lower part of the impregnating boiler.

15 cl, 2 dwg