Abstract: The removal of SO.sub.x and particulates, and preferably also NO.sub.x, from the combustion gases of a large boiler, is simplified while efficiency is improved. In a primary treatment zone, a slurry comprising an alkaline SO.sub.x -reducing composition and preferably a nitrogen-containing composition effective to reduce NO.sub.x, is introduced into combustion gases at a temperature of from about 900.degree. to about 1300.degree. C. The gases are cooled by initial contact with steam-generating means, and then by contact with an gas-to-gas heat exchanger. Cooled gases are then subjected to a secondary treatment in which they are first humidified and further cooled by introduction of a water spray or aerosol to reduce the temperature to 100.degree. C. or below. Contact between the SO.sub.x -reducing composition and the humidified gases is maintained for a reaction period of at least 2 seconds. Particulate solids are then separated from the gases with a fabric filter.

Abstract: An apparatus in the form of an air preheater for preheating air for combustion for a combustion process by acting upon the air with hot, NO.sub.x -containing flue gases from the same or an independent combustion process. At the same time, the NO.sub.x contained in the flue gases is reduced. A regenerative or recuperative type air preheater is used, with thoses surfaces of the heat exchange elements which are exposed to the flue gas being provided with a coating which acts as a catalyst for the NO.sub.x reduction. The heat exchange elements are coated only in a region which as a flue gas temperature greater than the condensation temperature of the reaction products of the materials contained in the flue gas and of the added reducing agent.

Abstract: An apparatus in the form of an air preheater for preheating air for combustion for a combustion process by acting upon the air with hot, NO.sub.x -containing flue gases from the same or an independent combustion process. At the same time, the NO.sub.x contained in the flue gases is reduced. A regenerative or recuperative type air preheater is used, with those surfaces of the heat exchange elements which are exposed to the flue gas being provided with a coating which acts as a catalyst for the NO.sub.x reduction. The heat exchange elements are coated only in a region which has a flue gas temperature greater than the condensation temperature of the reaction products of the materials contained in the flue gas and of the added reducing agent.

Abstract: A regenerative gas-gas heat exchanger having a column type of construction, and heat transferring elements which absorb heat in a hot gas flow, give off heat in a cold gas flow, and are cyclically conveyed from one of the gas flows to the other. The heat transferring elements form a fluidized bed during the operation; this fluidized bed, in relation to the gases which flow in an upward direction through the gas permeable column bottom, moves in a counter-cross flow over this column bottom.

Abstract: A method of regulating the amount of reducing agent added, especially NH.sub.3 in the case of the catalytic reduction of NO.sub.x of flue gases which originate from a combustion installation which is fired with fossil fuels. The adjustment value for the quantity to be added is determined in response to a prescribed reducing agent/NO.sub.x stoichiometry factor from the quantity of combustion air supplied to the combustion installation or from the exiting quantity of flue gas, and from the NO.sub.x concentration downstream ahead of the catalyzer. Regulation is effected by influencing the stoichiometry factor. The NO.sub.x concentration downstream after the catalyzer is returned to the regulation process as the primary correction value, and the reducing agent concentration downstream after the catalyzer, and the flue gas temperature ahead of the catalyzer, are returned to the regulation process as the secondary correction values.

Abstract: An apparatus in the form of an air preheater for preheating air for combustion for a combustion process by acting upon the air with hot, NO.sub.x -containing flue gases from the same or an independent combustion process. At the same time, the NO.sub.x contained in the flue gases is reduced. A regenerative or recuperative type air preheater is used, with those surfaces of the heat exchange elements which are exposed to the flue gas being provided with a coating which acts as a catalyst for the NO.sub.x reduction. The heat exchange elements are coated only in a region which has a flue gas temperature greater than the condensation temperature of the reaction products of the materials contained in the flue gas and of the added reducing agent.

Abstract: A regenerative gas-gas heat exchanger having a column type of construction, and heat transferring elements which absorb heat in a hot gas flow, give off heat in a cold gas flow, and are cyclically conveyed from one of the gas flows to the other. The heat transferring elements form a fluidized bed during the operation; this fluidized bed, in relation to the gases which flow in an upward direction through the gas permeable column bottom, moves in a counter-cross flow over this column bottom.

Abstract: A method of regulating the amount of reducing agent added, especially NH.sub.3 in the case of the catalytic reduction of NO.sub.x of flue gases which originate from a combustion installation which is fired with fossil fuels. The adjustment value for the quantity to be added is determined in response to a prescribed reducing agent/NO.sub.x stoichiometry factor from the quantity of combustion air supplied to the combustion installation or from the exiting quantity of flue gas, and from the NO.sub.x concentration downstream ahead of the catalyzer. Regulation is effected by influencing the stoichiometry factor. The NO.sub.x concentration downstream after the catalyzer is returned to the regulation process as the primary correction value, and the reducing agent concentration downstream after the catalyzer, and the flue gas temperature ahead of the catalyzer, are returned to the regulation process as the secondary correction values.

Abstract: Heat-transferring elements for regenerative heat exchange in a gas-gas fluidized bed heat exchanger. The elements are in the form of separate, freely movable saddle-shaped bodies. The saddle-shaped elements may have one or more holes, and may also, or alternatively, have one or more hollow spaces or chambers which are filled entirely or partially with materials of high heat-retaining capacity, and/or with latent storage masses.

Abstract: A heat storage mass or heat retainer made of at least two different materials, with the heat storage capacity of the entire mass being based predominantly upon the heat storage capacity of a first material, which is embedded in hollow spaces or chambers, or pores, which are uniformly or statistically distributed in a second carrier material.

Abstract: Heat-transferring elements for regenerative heat exchange. The elements are embodied as rigid hollow spheres or balls, or as hollow polyhedrons, with the free inner space or chamber thereof being partially filled with a heat-conducting liquid as well as vapor from this liquid. The hollow sphere may be provided with an elastic outer shell with reinforcing elements arranged in the interior thereof. The heat-transferring elements may be utilized as a whirl layer and/or static layer.

Abstract: A regenerative heat exchanger. The rotor is an annular body and includes several rotationally symmetrical chambers which are separated from one another by walls, with the axially parallel dividing walls being permeable for the gaseous heat-dissipating or heat-receiving medium, and the radial dividing walls being permeable for the gaseous medium; heat-transferring elements for the regenerative heat exchange are arranged in the chambers accompanied by formation of a whirl layer during operation. The chambers have radial flow therethrough.