Abstract: The invention provides a method for reducing the emission of NO.sub.x in a pressurized fluidized bed combustion process comprising (a) combusting reaction products in the presence of a sulfur absorbent in a pressurized fluidized bed at a pressure of at least 5 bar to form a flue gas comprising dust particles and an initial concentration of NO.sub.x, (b) reacting the NO.sub.x in the flue gas with a substance which reduces NO.sub.x in a first reaction zone to form a flue gas which has a lower NO.sub.x concentration as compared to its initial NO.sub.x concentration, wherein the absolute pressure of the flue gas is at least 5 bar and the temperature of the flue gas is at least 450.degree. C. in the first reaction zone, and (c) reducing the NO.sub.x concentration in the flue gas provided by step (b) in a second reaction zone by contacting the gas with a solid surface comprised of flue gas dust particles.

Abstract: A power plant with combustion of a fuel at a pressure exceeding the atmospheric pressure in a fluidized bed (14) in a bed vessel (12) which is enclosed within a pressure vessel (11). The space (37) between the pressure vessel (11) and the bed vessel (12) is supplied with combustion air from a compressor (22). Ash and consumed bed material are taken out from the bed vessel (12) via an ash chamber (34) and are cooled therein by air from the space (37). The air from the space (37) is cooled in a cooler (44) before being supplied to the ash chamber (34).

Abstract: A superheater has a pressure vessel containing upper and lower steam chambers for primary steam between which extends a nest of tubes arranged around a central volume. The volume between the nest of tubes and the pressure vessel is divided into lower and upper volumes by a wall which forces the secondary fluid to be superheated first to pass the nest of tubes radially inwardly into the central volume and thereafter radially outwardly. Primary steam is supplied to the upper steam chamber tangentially and flows under condensation through the tubes to the lower steam chamber where the condensate is discharged. Between the steam chambers a centrally located return conduit can be provided. The rotation of the steam within the upper steam chamber induces a pressure distribution with decreasing pressure from the periphery towards the center which pressure distribution is used for the recirculation of excess primary steam through the return conduit.

Abstract: A device for heating a fluent material (e.g., gaseous or liquid media, such as air, water, etc.) comprises one or more electrical induction coils arranged around one or more central conduits for the medium to be heated, inside which coils there are arranged rings or spirals of metals which form one or more electrically-closed circuits, possibly after addition of short-circuit parts, which circuits, and possible metallic partition walls at these, are arranged to be inductively heated when the induction coils are electrically energized, heat generated in the heating elements passing to the fluent material flowing through the passageways.

Abstract: A thermal recuperator for heating gas supplied to a vessel from which a hot gas is discharged and which allows the pressure in the vessel to be controlled substantially without regard to the pressure drop necessary to cause the hot gas to flow through the recuperator. The invention has particular utility in the case of a metallurgical ladle provided with a ladle heater, the combustion air for which is heated in a recuperator receiving waste gas from the ladle. A conduit for the waste gas leaving the ladle is surrounded by one or more conduits for the combustion air, and an ejector fed with combustion air is arranged at the gas outlet of the waste gas conduit to accelerate the waste gases and facilitate their egress from the recuperator.

Abstract: An intermediate steam superheater includes a heat exchanger comprising a bundle of tubes supplied with steam and subject to the disadvantage that the steam may condense completely in some of the tubes while passing freely through others of the tubes with a consequent loss of heating efficiency. This is corrected by sucking the steam from the outlet ends of the tubes and injecting it into the inlet ends of the tubes so that such a high flow rate occurs through the tubes that the tubes are kept substantially free from condensate while the steam is continuously recirculated through all of the tubes, the condensate from the condensed portion of the steam being discharged from the heat exchanger.