HEAT RECOVERY FROM THE WASTE COOKING LIQUID IN THE COOKING BOILER AT A PULP AND PAPER ENTERPRISE

摘要

1. A method of heating white liquor or a mixture of white liquor and other liquids for use in a pulp and paper mill digester system, where:! a) black liquor is obtained in the digester system,! b) the black liquor stream is removed from the digester,! c) the removed black liquor is flash evaporated to give black liquor that has passed flash, and the flash vapor,! d) flash vapor is supplied to an indirect heat exchanger in contact with at least one heat exchanger with white liquor and / or a mixture of white liquor and another solution to heat white liquor and / or mixture for use in a digester system, and! e) flash liquor from step c) is flash fed to additional heat recovery or evaporation. ! 2. The method according to claim 1, characterized in that in stage d) the other liquid for obtaining a mixture with white liquor is black liquor or a filtrate from the washed mass. ! 3. The method according to claim 1 or 2, characterized in that stage d) is carried out using a single heat exchanger to heat white liquor or mixture. ! 4. The method according to claim 3, characterized in that the heated white liquor or mixture is fed into the circulation circuit or circuits of the digester. ! 5. The method according to claim 1 or 2, characterized in that stage d) is carried out using a first heat exchanger and a second heat exchanger to heat white liquor or mixture. ! 6. The method according to claim 5, characterized in that the heated white liquor or mixture and the heated white liquor or mixture are supplied from the first heat exchanger to the circulating circuit or circulating circuits of the digester