Abstract: Method and apparatus for gasifying of a solid carbonaceous material in a fluidized bed reactor in which the solid particles entrained by the gases being removed from the upper part of the reactor are separated and returned to the lower part of the reactor. oxygenous gas is supplied into the lower part of the reactor and the non-reacted carbonaceous material separated from the gases is oxidized in the lower part of the reactor. The carbonaceous material is introduced above the oxidizing zone into a zone substantially free of oxygen and the carbonaceous material is pyrolyzed and reduced by means of the hot gases and particles rising from the lower part of the reactor.

Abstract: The invention relates to a method and a nozzle bottom for controlling the mixing of gaseous flows in fluidized bed reactors and circulating fluidized bed reactors. In the method, part of the combustion air is introduced into a reactor chamber through fluidizing nozzles (11) positioned in a nozzle bottom (4). In order to improve the controllability of a combustion process, the remaining part of the combustion air is according to the invention introduced through essentially vertically directed jet nozzles (12) positioned in the nozzles bottom (4), and the vertical penetration of the air jets applied through the jet nozzles (12) is maintained at a value essentially higher than the vertical penetration of the air jets applied through the fluidizing nozzles (11).

Abstract: Gases containing tar and other condensable components are cleaned by cooling them in a circulating fluidized bed reactor (2) provided with cooling surfaces (8). Into the fluidized bed reactor are led solids separated from the cooled gas in a cyclone separator (3) and other solids. Tar and other compounds condense on the solids in a mixing chamber (9) disposed before the cooling surface in the reactor.

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.