Abstract: The invention relates to a boiler for the production of steam, the boiler having a maximum capacity of 100 ton/hr or more and comprising a furnace having a substantially constant rectangular cross-section and a back pass with a substantially constant rectangular cross-section. The furnace and the back pass are mounted close to each other and means are provided for superheating the steam. The steam superheating means are positioned within the back pass, so that no superheater is positioned within the furnace.

Abstract: The invention relates to a boiler for the production of steam, the boiler having a maximum capacity of 100 ton/hr or more and comprising a furnace having a substantially constant rectangular cross-section and a back pass with a substantially constant rectangular cross-section. The furnace and the back pass are mounted close to each other and means are provided for superheating the steam. The steam superheating means are positioned within the back pass, so that no superheater is positioned within the furnace.

Abstract: The invention relates to a method of firing black liquor in recovery boilers where the intention is to obtain fumes having a low content of nitrogen oxides (NO.sub.x). A part of the combustion air is added as a last portion at a very high level so that a reducing atmosphere will exist in a very great part of the boiler for a long time period, e.g. at least 3-5 seconds.

Abstract: The present invention relates to a method for the combustion of waste liquids in connection with recovering of chemicals from the waste liquid, preferably black liquor from pulp production whereby the liquid (5A) is injected at a given level (4) into a furnace (1, 2, 3) in which the liquid (5A) initially is dried and the solid remainder thereafter is pyrolysed and finally burned and the chemicals are assembled on the bottom of the furnace while the exhaust gases (8) are going up through and out from the furnace (1, 2, 3) and whereby a part of the combustion air, so called primary air (11), is supplied at one or more levels (6) below said level (4) of liquid injection (5A) and another part of the combustion air, so called secondary air (12), is supplied at one or more levels (7) between said levels for liquid injection (4) and primary air supply (6) respectively, whereby the secondary air (12) is supplied to the furnace (1, 2, 3) in such a way that the gas is forced to rotate in a plane substantially perpendic

Abstract: A method and a particle cooler for controlling the cooling effect in a circulating fluidized bed reactor. The method comprises regulating heat output from the particle cooler by varying the particle level in the cooler. The particle cooler is mounted in a fluidized bed reactor having a particle flow restrictor with fluidizing means between the flow restrictor and reaction chamber and provides the only particle flow passage between the restrictor and reaction chamber and is provided with internal cooling media tubes dispersed on different vertical levels. Particle flow regulating means is provided for maintaining the particle level within the cooler, which level is adjustable.

Abstract: A cast air nozzle is adapted to be mounted on the bottom of a combustor, particularly a fluidized-bed combustor. The air nozzle comprises a substantially gun-shaped body having a substantially horizontal upper part with a front portion and a rear portion, and a substantially vertical lower part with a through, substantially vertical inlet duct, two substantially horizontal outlet ducts in the upper part extending from the upper end of the inlet duct and opening at the front end of the front portion. The outlet ducts diverge towards the front end of the front portion, whereby an air current flowing through the air nozzle is caused to leave the nozzle in the form of horizontal diverging air jets. The upper part has at the front portion a horizontal planar upper surface and at the rear portion a backwardly-downwardly inclined upper surface, said surfaces forming an angle with each other, whereby the material in the combustor, which is conveyed across the air nozzle, does not collect on the upper portion.