Abstract: Method of supplying ammonia gas to boilers having at least two fluidized beds one above the other for reducing the content of nitrogen oxides in the flue gas wherein the ammonia gas is intermixed with secondary air or tertiary air before said air intermixed with flue gas from the lower fluidized bed is supplied to the upper fluidized bed or the upper fluidized beds, respectively, for fluidization equally distributed over the area of the bed or beds, respectively.

Abstract: A multibed fluidized boiler having at least two fluidizable beds, in which conventional fuel, for example coal, is supplied to the first bed and in which the combustion of this fuel takes place in the first bed and in the following bed. An alternative fuel, such as wood chips, waste wood or paper, or combustible refuse, is adapted to be supplied to the second bed in order to be burnt there, thus obtaining a simplified fuel feeding to the second bed and increased protection against clogging of the nozzles for the supply of gas from the first bed to the second bed.

Abstract: A boiler plant with a multi-fluidized-bed combustion chamber comprising a first bed in a lower combustion space and a second bed in an upper combustion space and with nozzles in the support means for the beds for injection of combustion air into the first bed and combustion gases into the second bed for fluidization of the bed material therein. The plant is equipped with bed material transport devices for transferring bed material from the lower combustion chamber to the upper combustion chamber or vice versa. Further, measuring means is provided for measuring the temperature and depth of the lower bed, and signal processing and control means are provided for adapting the depth of the lower bed in dependence on plant load and bed temperature.

Abstract: A nozzle cap for a gas inlet fluidizing nozzle in the bottom plate of a post-combustion bed in a hot water or steam boiler with at least two fluidized beds is provided. Flue gases from an underlying combustion bed enter the post-combustion bed via a plurality of such gas inlet nozzles. Each nozzle cap is formed as a deflecting member for guiding the flue gases to the bed material and is shaped to minimize the risk of clogging of the cap with particles entrained in the flue gases and the risk of the cap being eroded by the fastly moving particles.

Abstract: A fluidizable bed combustion chamber comprises an intermediate partition (2,7) which divides the chamber into an upper combustion space (1a) and a lower plenum (1b) and which is provided with means (4,4a,8) for injecting fuel into the upper combustion space in which, during use of the combustion chamber, a bed of fluidized material (6) is created. The intermediate partition is composed of a plurality of nested modules (7), each of polygonal shape and having a substantially centrally positioned fuel supply member (8). Each corner surface (9) of each module is upwardly inclined in the direction away from the center of the module, and these corner surfaces are provided with openings (10) enabling air to be injected into the upper combustion space from the plenum chamber. Preferably, the modules are of regular polygonal shape, for example triangular, quadratic or hexagonal.

Abstract: A combined nozzle for air and fuel to a fluidized bed (20) comprises two fixed portions (1, 10) mounted at the top and bottom of an air chamber (4) and a movable, withdrawable portion (2) which connects the two fixed portions and is guided by them. The movable portion blocks the lower fixed portion (10) outwardly and conducts air and fuel to the upper fixed portion (1). Further, there is a device (3, 26) for sealing the lower fixed portion when the movable portion is removed for inspection during operation. (FIG. 2).