Abstract: A method for reducing corrosion of a superheater of a steam boiler. The superheater includes a superheater piping. The superheating piping includes a steam pipe where the steam to be superheated is directed. The steam pipe is separated by a protective shell having a surface settling in the flue gas space has a temperature that rises above an upper critical temperature, above which temperature in the flue gas space the compounds from the fuel are substantially in a gaseous form. A superheater of a steam boiler and a circulating fluidized bed boiler.

Abstract: The invention relates to a method and equipment for treatment of black liquor at a pulp mill in order to recover chemicals and energy contained therein. In the invention, the black liquor is pyrolyzed in a pyrolysis reactor (4), the formed gaseous components are forwarded for utilization and the solids are mixed with water, whereby the formed solids are returned to a lime burning kiln (1) and the sodium-hydroxide-containing liquid is returned to the pulp cooking process.

Abstract: The invention relates to a method and apparatus for processing the black liquor of a pulp mill to recover the chemicals and energy therein. In the invention, the black liquor is pyrolyzed in a pyrolysis reactor (6), formed gaseous components are lead for utilization, sand is returned to a fluidized-bed boiler, and solid matter is mixed with water, whereby a soda-water solution is returned to the pulping process and solid carbon to the fluidized-bed boiler (1).

Abstract: The invention relates to a method and apparatus for processing the black liquor of a pulp mill to recover the chemicals and energy therein. In the invention, the black liquor is pyrolyzed in a pyrolysis reactor (4), formed gaseous components are lead for utilization, sand is returned to a fluidised-bed boiler, and solid matter is mixed with water, whereby a soda-water solution is returned to the pulping process and solid carbon to the fluidised-bed boiler (1).

Abstract: The invention relates to a method and equipment for treatment of black liquor at a pulp mill in order to recover chemicals and energy contained therein. In the invention, the black liquor is pyrolyzed in a pyrolysis reactor (4), the formed gaseous components are forwarded for utilization and the solids are mixed with water, whereby the formed solids are returned to a lime burning kiln (1) and the sodium-hydroxide-containing liquid is returned to the pulp cooking process.

Abstract: A method for reducing corrosion of a superheater of a steam boiler. The superheater includes a superheater piping. The superheating piping includes a steam pipe where the steam to be superheated is directed. The steam pipe is separated by a protective shell having a surface settling in the flue gas space has a temperature that rises above an upper critical temperature, above which temperature in the flue gas space the compounds from the fuel are substantially in a gaseous form. A superheater of a steam boiler and a circulating fluidized bed boiler.

Abstract: A method for treating lime mud, in which method the lime mud is conveyed to a lime kiln, where fuel gas is used as fuel, which fuel gas is formed by a circulating fluidized bed gasifier. A calcium compound is used as bed material in the gasifier. In addition, the invention relates to the use of a calcium compound in a lime mud treatment plant, as well as to a lime mud treatment plant.

Abstract: A method for shielding the inner surface above the shield refractory (4) of the furnace wall (3) of a circulating fluidized bed boiler from erosion caused by suspension flows, in which method a shield structure is formed on the inner surface of the boiler wall. At least a first zone (1) and a second zone (2) are formed in the shield structure, the erosion-resistance properties of which zones differ from each other. In addition the invention relates to a circulating fluidized bed boiler, which comprises a corresponding shield structure.

Abstract: The object of the present invention is a method in cooling medium circulation, whereby the recovery boiler comprises a furnace limited by wall tubes provided with cooling medium circulation and substantially horizontal floor tubes; a supply system for combustion air; and a supply system for black liquor, whereby a so-called smelt layer is formed in a combustion process on the floor composed of the floor tubes. At least in some of the floor tubes, at least on a section of their length, is arranged a longitudinal flow--particularly a spiral flow--for mixing the liquid and steam phases of the cooling medium.

Abstract: A process for the recovery of heat and chemicals from spent liquor by evaporating water out from it in order to concentrate the liquor and be feeding the concentrated liquor thereby obtained and air into the soda-ash furnace. In order to increase the dry-matter content of the liquor to a level higher than usual, without at the same time increasing the viscositty of the liquor immoderately, at least the final concentrating (5, 9) of the liquor and its feeding (16) into the soda-ash furnace (4) are carried out under pressure at a temperature higher than the atmospheric boiling point of the liquor.