Abstract: The bed depth in a power plant burning sulfur-containing fuel in a fluidized bed of material which constitutes a sulfur absorbent in a combustion chamber is controlled on the basis of plant power output. A plurality of sensors connected to the combustion chamber determine the existing bed depth. A bed material mill grinds material removed from the bed prior to returning it to the bed, the rate at which the mill operates being controlled by the extent to which the actual bed depth differs from the desired bed depth. The mill grinds some bed material to small enough size for it to be carried from the combustion chamber with the combustion gases.

Abstract: The corners of the walls of a vessel in which fuel is burnt in the fluidized bed of a PFBC power plant are articulately connected to a supporting framework. The forces arising on the bed vessel walls are taken up by the framework and are transmitted to the framework by means of a plurality of links. At each corner the construction of links allows the corner to be displaced in relation to the framework. This corner-connection includes auxiliary beams which are substantially parallel to the walls and are at one of their ends articulately connected to the framework.

Abstract: A power plant with combustion of a fuel in a fluidized bed is enclosed within a bed vessel. It includes one or more cleaners for separating dust from the combustion gases leaving the bed. The gas cleaner is built up as a panel or unit with a number of parallel-connected centrifugal cleaners, with a first cylindrical inlet part with guide vanes which impart a rotating movement to the gas flowing through, and a second cylindrical part sliding into the first part and together with this forming an annular gap with an outlet which communicates with a common space and/or with a separator arranged in series with the parallel separators. The panel or unit is directly connected to an outlet opening from the bed vessel and forms part of a bed vessel wall.

Abstract: A method for drying, crushing and distribution of solid fuel for a solid fuel boiler, for example a fluidized bed boiler. The method is characterized in that moist fuel is crushed and dried by intermixing gas and/or ash, and that the fuel is set in motion, for example in a cyclone together with gas, the fuel thus being divided into several sub-flows for feeding into the boiler at different points.

Abstract: A power plant with combustion of a fuel in a fluidized bed (14) enclosed within a combustion chamber in a bed vessel (11). A gas outlet from the bed vessel (11) is formed as a centrifugal separator (20) intended to primarily separate coarse material containing unburnt fuel leaving the bed (11) together with the combustion gases. Suitably the separator (20) extends into the bed vessel (11) and separated material is returned to the bed (14) through a return conduit (34), which is preferably located close to the bed vessel wall. This conduit (34) opens into the bed vessel (11), near the bottom (12) thereof. For the return transport an ejector (35) may be used to overcome the pressure difference existing between the separator (20) and the orifice of the conveying conduit (34). The propellent gas may consist of combustion air from the space (16).

Abstract: A power plant designed to burn fuel in a bed of fluidizable particulate material contained in a combustion chamber includes a tubular discharge device for bed material or dust separated from combustion gases leaving the combustion chamber. The tubular discharge device is designed as a cooler which is cooled by combustion air flowing into the combustion chamber and is utilized for pre-heating the plant upon start-up from a cold state. At least a part of the tubular discharge device, is electrically insulated from parts located upstream and downstream and from supporting structural members and forms an electrical heating unit. Upon start-up, this unit is connected to a current source for heating the air fed to the combustion chamber and downstream parts of the plant.

Abstract: A pneumatic transportation system for transferring particulate material from a storage container at one pressure level to a receiving unit at another pressure level (e.g. in a feeding system for bed material to a combustion chamber of a PFBC plant). The transportation system incorporates a material feeder comprising a housing having a rotor containing two material chambers. The end walls of the housing and the rotor have cooperating sealing surfaces. The inlet opening of one material chamber is positioned opposite to an inlet opening in the upper end wall of the housing, when the outlet opening of the other material chamber is positioned opposite to an outlet opening in the lower end wall of the housing. After rotation of the rotor the inlet opening of the material chamber will be positioned opposite to the inlet opening and the outlet opening of the chamber will be positioned opposite to the outlet opening. Between the actual material chambers and the outlet openings there are cut-off valves.

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 PFBC plant which includes a gas cleaner located inside an air-filled pressure vessel is provided with means to detect erosion damage in the gas cleaner. Portions of the wall of the gas cleaner which are exposed to erosion damage are surrounded by a space defined by a gas-tight mantle. The mantle has an opening which provides a connection between the defined space and the air in the pressure vessel. Adjacent the opening is a device for indicating when air flows through the opening into the defined space.