Patent ID: 6647726
Filing Date: 2003-11-18
Classification: D21C,F01K,Y02E

Abstract:
In a method for production of electric energy in a boiler plant of a pulp mill, said method comprising:feeding black liquor having a dry solids content of more than 80% and combustion air into a furnace of a recovery boiler for combusting the black liquor and recovering chemicals contained therein, flue gases generated in the combustion of the black liquor flow to an economizer of the recovery boiler, in which economizer feed water for the boiler is heated, and the flue gases flow from the economizer to a gas cleaning device, feed water flows from the economizer to a steam-generating bank at a temperature below a saturation temperature of the water, and further the water flows to a superheater to produce steam having a pressure of more than 80 bar, steam from at least the steam generating bank flows from the recovery boiler to a steam turbine to produce electricity, steam discharged from the steam turbine preheats the feed water flowing into the economizer, wherein the temperature of the feed water flowing into the economizer is regulated by bleed steam of the turbine so that the flue gases exit the economizer at a temperature of more than 250Â° C. and that after the economizer the flue gases are cleaned in at least a hot electrostatic precipitator and the cleaned flue gases are cooled by the combustion air or the feed water.