In a method for reducing the NOx emissions of a rotary kiln of a clinker production plant, fuel supplied through a burner of the rotary kiln is burned along with primary air fed through the burner, wherein the primary air has a lower oxygen content and the primary air has an oxygen content reduced relative to that of the ambient air and a temperature increased relative to that of the ambient air, and the primary air is obtained by mixing ambient air with exhaust gas from the rotary kiln or from a heat exchanger connected to the rotary kiln and used for preheating raw meal. The primary air is further obtained by mixing with hot air, in particular waste air from a clinker cooler.

Method of operating a long direct-fired inclined counterflow rotary kiln for the thermal treatment of material and counterflow rotary kiln adapted for same, whereby material to be treated is introduced into the kiln at the inlet end and treated material is evacuated from the kiln at the outlet end, whereby a main combustion zone extends inside the kiln over a distance of to of the internal length L.sub.int of the kiln, whereby a supplementary combustion zone in which supplementary combustion takes place with an oxygen-rich oxidant extends inside the kiln over a distance from the inlet end of at most of the internal length L.sub.int, and whereby no combustion takes place in a heat exchange zone located between the main combustion zone and the supplementary combustion zone.

A powder metallurgical component has a chromium content of at least 80% by weight and pores and/or oxide inclusions which are present in the component. The number per unit area of a sum of pores and oxide inclusions at a cut surface through the component in at least one region is at least 10,000 per mm.sup.2.

A method and system for thermal processing of a material conveyed in a rotary kiln with a rotatable kiln drum, the drum wall of which delimits a heatable drum chamber, from a drum inlet to a drum outlet of the kiln drum. The drum chamber is heated directly by conducting a heating gas into the drum chamber. The drum chamber is also heated indirectly by warming the drum wall at least in areas.

In a method for reducing the NOx emissions of a rotary kiln of a clinker production plant, fuel supplied through a burner of the rotary kiln is burned along with primary air fed through the burner, wherein the primary air has a lower oxygen content and the primary air has an oxygen content reduced relative to that of the ambient air and a temperature increased relative to that of the ambient air, and the primary air is obtained by mixing ambient air with exhaust gas from the rotary kiln or from a heat exchanger connected to the rotary kiln and used for preheating raw meal. The primary air is further obtained by mixing with hot air, in particular waste air from a clinker cooler.

The invention relates to a cooling system (3) for rotary furnaces (1), and also to a method for operating such a cooling system (3). The cooling system (3) comprises for this purpose an arrangement of one or more cooling modules (31, 31, 31), which are arranged in the portion (21) to be cooled of the furnace shell (2), at least along the axis of rotation (R) of the furnace shell (2), wherein each cooling module (31) comprises an activatable switching valve (311) and a fan nozzle (312) for issuing a pulsed fan-shaped cooling liquid jet (4) and, when there are a number of cooling modules, the neighbouring cooling modules (31, 31, 31) are arranged in relation to one another at a distance (A1) parallel to the axis of rotation (R) of the furnace shell (2). Each cooling module (31, 31, 31) comprises at least one first heat sensor (313), connected to a cooling system control (32), for measuring a first local temperature (T1) of the furnace shell (2) ahead of the area of impingement (41) as seen in the direction of rotation (DR) of the furnace shell (2).

The invention concerns: A) An assembly to reduce the emission of CO.sub.2 in a plant for the production of clinkers comprising two calciners and a carbonator arranged between the two calciners, wherein one of the calciners is an integral part of a conventional clinker production system. Thanks to this assembly, the plant can continue to operate in the clinker production process even if the CO.sub.2 capture system which uses the carbonator and the other calciner of the assembly is disconnected due to malfunctions or maintenance characterized in that said carbonator is free of recirculation to both said two calciners. B) The relative plants comprising both the assembly and the actual clinker production plant in which the clinker production plant is of the conventional type existed before and already operational, or said plant is installed simultaneously with the assembly units. C) The clinker production process with reduction of CO.sub.2 emission conducted in the plants B.

The invention concerns: A) An assembly to reduce the emission of CO.sub.2 in a plant for the production of clinkers comprising two calciners and a carbonator arranged between the two calciners, wherein one of the calciners is an integral part of a conventional clinker production system. Thanks to this assembly, the plant can continue to operate in the clinker production process even if the CO.sub.2 capture system which uses the carbonator and the other calciner of the assembly is disconnected due to malfunctions or maintenance characterized in that said carbonator is free of recirculation to both said two calciners. B) The relative plants comprising both the assembly and the actual clinker production plant in which the clinker production plant is of the conventional type existed before and already operational, or said plant is installed simultaneously with the assembly units. C) The clinker production process with reduction of CO.sub.2 emission conducted in the plants B.

The present invention provides a method of generating combustible gas from organic feedstock, such as the organic components of municipal waste, and a reactor therefor. The feedstock is processed through a plurality of reaction zones within the reactor, wherein the environment of each of the zones facilitates physical or chemical reactions that work to transform the organic feedstock into one or more combustible gases that can be burned for energy production.

The present invention provides a method of generating combustible gas from organic feedstock, such as the organic components of municipal waste, and a reactor therefor. The feedstock is processed through a plurality of reaction zones within the reactor, wherein the environment of each of the zones facilitates physical or chemical reactions that work to transform the organic feedstock into one or more combustible gases that can be burned for energy production.