Abstract: A method and apparatus for recovering black liquor chemicals and heat in a sulphate pulp process. The black liquor is concentrated in an evaporation plant, which includes a pressure heating reactor, after which the black liquor is gasified or combusted in a reactor for producing hot gases. The hot gases formed in the reactor are introduced into gas turbine power plant. The exhaust gases from the gas turbine are introduced into a waste heat boiler, where steam is generated for a steam turbine power plant. Secondary steam is led from the pressure heating reactor as injection steam into the gas turbine, to control inlet temperature.

Abstract: A method of decreasing the viscosity and improving the evaporability of sulfate black liquor from the cellulose cook includes raising the temperature of the black liquor above the cooking temperature so as to split the macro-molecular lignin fraction contained in the liquor. The temperature of the black liquor is maintained at the raised level for 1 to 60 minutes, preferably for 1 to 5 minutes.

Abstract: A method of concentrating sludges wherein liquor is heated under pressure indirectly with flue gases from the combustion of previously concentrated sludge, after which the sludge is caused to expand or subjected to reduced pressure which results in evaporation of water and concentration of the sludge to a dry-substance content of over 55%.

Abstract: A method of recovering alkaline chemicals from a material containing sodium or potassium compounds. The material is gasified by an external heat source after which the gas is rapidly cooled by arranging it to contact with cooled solid particles separated from the gas.