Abstract: A fluidized bed reactor (1) comprising a reactor chamber (4) having a gas distributor plate (5) for feeding primary air, and a space above said distributor plate (5) is divided into compartments (6) by means of partition walls (7) having discharge openings (9) for feeding secondary air to the circulating bed.

Abstract: A method and an apparatus for separating coarse and fine solid particles from flue gases in a circulating fluidized bed reactor provide for flue gases to be led to a cyclone separator, located adjacent the reactor. A discharge opening is provided in the lower portion of the separator, opening into a suction chamber interposed between the discharge opening and a return duct. Coarse particles are returned to the reactor via the return duct while fine particles are pulled into a suction pipe connected to the suction chamber, and are then returned to the reactor separately from the coarse particles. At the same time, a minor portion of the flue gases are removed through the discharge opening in the separator with the solid particles and returned to the reactor. The major portion of the flue gases is discharged through an opening in the upper portion of the separator.

Abstract: A separator for separating solid particles from a hot gas stream comprises a cyclone chamber having an axial gas outlet conduit. The outlet conduit is formed by a plurality of cooling tubes defining between the tubes a plurality of passages for the gas. The outlet conduit is connected to an opening in one or both ends of the cyclone chamber. Solids are separated by centrifugal forces as the gas flows in a curved path in the cyclone chamber and by inertia forces as the gas changes direction to flow into the outlet conduit.

Abstract: The invention comprises a circulating fluidized bed boiler having a vertical combustion chamber and a convection part which at least partly are formed by tube walls, and a horizontal cyclone separator, the gas inlet channel of which is connected to the upper part of the combustion chamber and a return channel for solids to the lower part of the combustion chamber. In order to accomplish a compact construction, the cyclone separator has been located on top of the combustion chamber and two opposite tube walls of the combustion chamber and possibly also one tube wall of the convection part have been used to form the cyclone separator.

Abstract: The invention comprises an apparatus for separating solids from flue gases in a circulating fluidized bed reactor having a horizontal cyclone separator, the gas inlet channel of which is connected to the upper part of the reactor, a return channel of the solids to the lower part of the reactor, and a gas outlet to a convection part of the reactor. In order to accomplish a compact construction, there is a plurality of coaxial turbulence chambers in the cyclone separator, the opposite walls of which form gas outlet channels between the turbulence channels.

Abstract: Heat energy is generated from low-grade alkaline fuels (such as manure and lignite) in a gasifier-combustor system. The fuel is gasified at a temperature of less than 900.degree. C. in a circulating fluidized bed gasifier comprising a first cyclone separator. The gas leaving the first separator is conveyed to a second cyclone separator. The gas leaving the second separator is burned in a boiler at a temperature of at least 900.degree. C. Alkaline containing material is removed and collected from the gasifier, the first and second separators, the boiler and a filter before the gas is vented to the atmosphere.

Abstract: A simple yet effective method and apparatus control the temperature within a fluidized bed reactor within a desired range (e.g. about 800.degree.-950.degree. C.). Particulate solids in the off-gases from the combustion chamber of the reactor are separated out, and pass through one or more of a plurality of return conduits back to the combustion chamber. The temperature of the returning solids is controlled by positively cooling them, utilizing heat exchangers, within one or more of the conduits, and by controlling which of the conduits the solids flow through. Valves at the top of the conduits can control the flow of solids into the conduits. Alternatively U-shaped passageways at the bottom of the conduits between them and the combustion chamber can have fluidizing air injected therein, the injected air controlling the flow of solids out of the conduits into the combustion chamber.

Abstract: An apparatus to be used in connection with a circulating fluidized bed reactor for separating solid material from flue gases and for recycling the solid material to the reactor. The apparatus comprises two adjacent, mainly horizontal, concentric vortex chambers of different sizes that have discharge openings concentric with the vortex chamber. The vortex chamber having a greater diameter is connected with the reactor via a gas inlet duct that is tangentially connected with the same vortex chamber. The vortex chamber having a smaller diameter is equipped with a gas inlet concentric with the smaller diameter vortex chamber, which inlet is connected with the gas discharge opening in the larger vortex chamber. Return ducts for the separated solid material are connected with openings on the periphery of the vortex chambers.

Abstract: In a two-stage combustion method first and second circulating fluidizing bed systems are utilized. The first bed system is operated under reducing (sub-stoichiometric) conditions so as to minimize NO.sub.x formation. Solids in the flue gases are separated and returned to the first bed system, while the flue gases are subjected to afterburning in the second bed system. Oxygen containing gas is supplied to the second bed system to effect afterburning, and additionally sulfur absorbing and/or NO.sub.x formation decreasing agents are supplied to the second system. When burning coal, the first system is operated at a temperature of about 700.degree.-1000.degree. C., while the second system is operated at about 600.degree.-950.degree. C. The flue gases may be cooled, just prior to effecting separation of the solids, in one or both of the bed systems.

Abstract: A fluidized bed reactor e.g. for the burning of fuels of different calorific values. The bottom part of the combustion chamber is divided into an outer and an inner fluidization zone by a partition wall adjacent to the distributor plate. Heat transfer surfaces are disposed in the outer fluidization zone. Heat can be withdrawn from the outer fluidization zone which is activated when burning fuel having a high calorific value. When burning fuel of lower calorific value the outer fluidization zone is not operated. The inner fluidization zone will be in operation in both cases. The supply of fluidizing gas to the second fluidization zone is controlled in order to maintain predetermined conditions in this zone.

Abstract: A fluidized bed reactor which is capable of burning material containing incombustible matter which during operation accumulates in the form of large particles in the lower part of the reactor, is provided. A discharge system which causes coarse particles to be discharged in a continuous manner without discharging fine particles or combustible matter is provided. The discharge means comprises a discharge compartment connected to an outlet of the distributor plate of the reactor. An upward flow pipe is centrally disposed in the discharge compartment. Air is supplied to the lower part of the discharge compartment. Coarse particles are withdrawn from the discharge compartment through a discharge pipe. Fine particles are blown back to the reactor through the upward flow pipe.

Abstract: A method of treating materials in a fluidized bed reactor, wherein the material to be treated is brought into contact with hot particles removed from the flue gases coming from the fluidized bed reactor to bring about chemical and/or thermal reactions in the material before it is introduced into the fluidized bed reactor together with recycled particles. Useful components may be recovered in the form of gases, solids or liquids in connection with this treatment.