Abstract: A method and a system for feeding combustion air of a soda recovery boiler to a furnace. The air is fed to the boiler furnace as primary air jets and auxiliary airjets, which are substantially shorter than the primary air jets. At least one primary airjet is placed between two opposite auxiliary air jets.

Abstract: A method and a system for feeding combustion air of a soda recovery boiler to a furnace (7), in which the air is fed to the boiler furnace (7) as primary air jets (5) and auxiliary air jets (6), which are substantially shorter than the primary air jets. According to the invention, at least one primary air jet (5) is placed between two opposite auxiliary air jets (6).

Abstract: In a soda recovery boiler, flue gases are led through a so-called economizer (3) to recover heat from flue gases. The flue gases are cooled in the last stage (3b) of the economizer (3) with a circulation water cooler (4) for flue gases, separate from the supply water system of the boiler. The circulation water cooler (4) for flue gases is used for preheating combustion air.

Abstract: In a soda recovery boiler, flue gases are led through a so-called economizer (3) to recover heat from flue gases. The flue gases are cooled in the last stage (3b) of the economizer (3) with a circulation water cooler (4) for flue gases, separate from the supply water system of the boiler. The circulation water cooler (4) for flue gases is used for preheating combustion air.

Abstract: Arrangement in a soda recovery boiler, comprising normal melt chutes (6) for removing molten salt from the recovery boiler (1). The recovery boiler (1) comprises an outlet (8), mounted in the wall of the recovery boiler such that it is situated lower down than the normal melt chutes (6), in which case the molten salt can be removed from the bottom of the recovery boiler substantially through the outlet (8), when the recovery boiler (1) is emptied for maintenance or the like.

Abstract: A method and an arrangement for supplying air to a fluidized bed boiler are disclosed. In the method, the air is supplied from all comers of the fluidized bed boiler substantially parallel to two opposite walls and from the middle of said walls toward the center of the fluidized bed boiler whereby the air flows cause the formation of four vortexes in the fluidized bed boiler. The arrangement comprises nozzles that blow air jets towards each other parallel to the opposite walls of the fluidized bed boiler and nozzles in the middle of the walls arranged to blow air toward the center of the fluidized bed boiler.

Abstract: In a recovery boiler for burning spent liquor of a pulp mill, a combustion chamber has heat transfer walls formed of tubes, at least one vertical heat transfer surface formed of tubes, and superheaters in an upper part of the combustion chamber for recovering heat generated by combustion and for cooling flue gases. The at least one vertical heat transfer surface divides the combustion chamber in a transverse direction into two combustion spaces.

Abstract: A method and an arrangement for supplying air to a recovery boiler. In the method, the air is supplied to the recovery boiler at at least one air supply level so that four vortices are formed therein, the vortices spinning, in pairs, in opposite directions to one another so that any two adjacent vortices always spin in opposite directions to one another. The arrangement comprises nozzles that are arranged to blow air so that four vortices are formed in the recovery boiler, any two adjacent vortices always spinning in opposite directions to one another.

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.

Abstract: The invention relates to a process and apparatus for causing the sulfur dioxide of flue gases to react to form solid sulfates and sulfites which can be separated from the flue gases. Sulfur dioxide containing flue gases (16) are directed according to the invention into one end of an oblong reaction zone (4), in addition to which pulverous calcium compounds and water are directed separately into the reaction zone at several points, and finally from the opposite end a flue gas suspension is withdrawn and directed to dust separation (5). By feeding the pulverous reagent and the water separately into the reactor 4, the problems involved in the preparing, handling and spraying of an aqueous slurry are avoided, in addition to which the retention time and the reaction conditions can be regulated easily in the oblong reactor 4.