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: An apparatus for screening pulp comprises a vessel, a cylindrical screen within the vessel, a rotating element moving in the vicinity of the screen at a predetermined speed, an inlet for the unscreened pulp, an outlet for the screened pulp in the vessel. The rotating element has a contour surface with grooves formed of a first plane parallel to the envelope surface, an inclined plane, an upper plane and a side plane, the side plane being essentially perpendicular to the first plane, the inclined plane forming an angle between 30.degree.-60.degree. with the first plane, the upper plane being parallel to the first plane. The rotating element may be a rotor or blade type segments.

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: In an apparatus for separating gas from a high consistency fibre suspension, the apparatus comprising a rotor chamber (2) containing a first rotor (11) provided with blades (10), a gas space (3) containing a second rotor (13) provided with blades (12), a wall disposed between the rotor chamber and the gas space consititutes an annular gas discharge channel surrounding a shaft rotating the rotors. Rotating blades (14) are disposed in the gas discharge channel between the first and the second rotor.

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.