Recovery of heat from black liquor during pulp production process, comprises supplying black liquor and bleaching filtrate to heat exchanger

摘要

Black liquor and a bleaching filtrate obtained from a bleaching plant are supplied to a heat exchanger (11) and the heated filtrate is then used in the plant. A method for recovering heat from black liquor which has been withdrawn from a digester (10) during a cellulose pulp production process comprises supplying at least a part of the black liquor to a heat exchanger, where an exchange of heat takes place between the black liquor and a bleaching filtrate obtained from a bleaching plant. The heated bleaching filtrate is then used in the bleaching plant. The temperature inside the digester is 130-180[deg] C.