A method for denitrification of flue gases and a system, wherein flue gases generated in a rotary kiln are conveyed to a calcining zone for the deacidification of raw cement meal. Aqueous ammonia solution, ammonia, or ammonia-releasing substances for denitrifying the flue gases injected into the calcining zone according to the method of selective non-catalytic reduction (SNCR), and the flue gas stream, together with an ammonia slip generated during the denitrification, is passed through a heat exchanger and through at least one dedusting device. The flue gas is guided through a exhaust gas line via a catalyst for the decomposition of excess ammonia with residues of nitrogen oxide in accordance with a method of selective catalytic reduction (SCR), wherein the catalyst is arranged in a reactor provided in the exhaust line, and is no larger than is required for a sufficient decomposition of the ammonia.

Methods and apparatus for reducing the content of controlled acidic pollutants in clinker kiln emissions are disclosed. The methods and apparatus include introducing bypass dust produced during production of clinker into one or more locations between the preheater exhaust and the inlet to a dust filter including into a gas conditioning tower. Total bypass dust separated from the kiln exhaust gas may be used. The bypass dust can be separated into a fine and coarse portions. Fine or total bypass dust can be mixed with water to form a bypass dust slurry that can be introduced into the gas conditioning tower. Bypass dust can be used to reduce the content of acidic pollutants such as hydrogen chloride HCl and sulfur oxides SO.sub.x from clinker kiln emissions.

A method for controlling an NOx concentration in an exhaust gas in a combustion facility by: measuring a reaction velocity k.sub.i of each of a plurality of chars, each corresponding to a plurality of types of pulverized coals; determining a relationship between the NOx concentration in the exhaust gas and the reaction velocity k.sub.i for each of the chars; (iii) blending the plurality of the types of the pulverized coal, wherein a blending ratio of the plurality of the types of the pulverized coal is determined by using, as an index, a reaction velocity k.sub.blend of the char of the blended pulverized coal, which corresponds to a target NOx concentration or below, on the basis of the relationship; and supplying the blended pulverized coal to the combustion facility as the fuel of the combustion facility.

A combustion gas bleeding probe includes a gas pipe for bleeding a part of a combustion gas from a kiln, and a plurality of discharge ports each of which is provided penetrating through the gas pipe and each of which discharges a low-temperature gas in a direction that is perpendicular to a direction of flow of a bleed gas bled by the gas pipe and that is directed toward a center of the flow of the bleed gas. The discharge ports discharge the low temperature gas such that a ratio of a momentum of the low-temperature gas per discharge port to a momentum of the bleed gas satisfies 1.2 to 4.0, and a value (m-1) obtained by dividing a ratio of a wind speed of the low-temperature gas to a wind speed of the bleed gas by an inner diameter of the gas pipe satisfies 1.5 to 3.5.

A method for controlling an NOx concentration in an exhaust gas in a combustion facility by: measuring a reaction velocity k.sub.i of each of a plurality of chars, each corresponding to a plurality of types of pulverized coals; determining a relationship between the NOx concentration in the exhaust gas and the reaction velocity k.sub.i for each of the chars; (iii) blending the plurality of the types of the pulverized coal, wherein a blending ratio of the plurality of the types of the pulverized coal is determined by using, as an index, a reaction velocity k.sub.blend of the char of the blended pulverized coal, which corresponds to a target NOx concentration or below, on the basis of the relationship; and supplying the blended pulverized coal to the combustion facility as the fuel of the combustion facility.

A method for manufacturing cement clinker includes the steps: preheating a raw meal in a first preheater using kiln off-gas to provide a partially preheated raw meal, preheating the partially preheated raw meal in a second preheater to provide preheated raw meal, precalcination of the pre-heated raw meal in a calciner being a circulating fluidized bed reactor by burning fuel with oxygen and recirculated calciner exhaust gas instead of air to provide a precalcined raw meal wherein at least 2 mbar overpressure are adjusted in the calciner, transferring the precalcined raw meal to a rotary kiln for sintering to provide the cement clinker, cooling the cement clinker, and capturing carbon dioxide from a calciner exhaust gas in a carbon dioxide purification unit.

A cement clinker producing system, capable of providing a gas containing a carbon dioxide gas at a high concentration by increasing a carbon dioxide gas concentration for a part of an exhaust gas, includes a cyclone preheater to preheat a cement clinker raw material, a rotary kiln to burn the preheated cement clinker raw material so as to provide cement clinker, a calcination furnace to promote decarbonation of the cement clinker raw material, a clinker cooler to cool the cement clinker, a kiln exhaust-gas discharge passages to discharge an exhaust gas generated in the rotary kiln, a combustion-supporting gas supply device to supply a combustion-supporting gas having a higher oxygen concentration than air, a combustion-supporting gas supply passage to guide the combustion-supporting gas to the calcination furnace, and a calcination furnace exhaust-gas discharge passage to discharge a carbon dioxide gas-containing exhaust gas generated in the calcination furnace.

A device for thermal treatment comprises at least a preheater, a calciner, and a materials cooler, wherein a solids stream is guided into the preheater, from the preheater into the calciner, from the calciner into the materials cooler, and out of the materials cooler, wherein a gas stream is guided into the materials cooler, from the materials cooler into the calciner, from the calciner into the preheater, and out of the preheater, wherein the device comprises a combustion chamber, wherein the gas stream from the materials cooler is guided at least partially through the combustion chamber into the calciner, wherein a residence time device is arranged between the combustion chamber and the calciner.

The present disclosure provides an energy-efficient (low energy consumption), carbon enriched cement production system and a method for producing cement clinker. This system involves raw material preheating and precalcining system and sequentially connected kiln inlet chamber, rotary kiln and cooler, wherein the raw material preheating and precalcining system involves precalciner and preheater, and the cooler involves first cooling zone and second cooling zone. The first cooling zone includes first cooling partition and second cooling partition, wherein a mixture of pure oxygen and high-concentration CO.sub.2 flue gas entering the inlet of the first cooling partition, high-concentration CO.sub.2 flue gas entering the inlet of the second cooling partition, and air entering the inlet of the second cooling zone have solved the problems in existing cement kiln CO.sub.2 enrichment technology, i.e., extensive air leakage and high energy consumption between the first cooling zone and the second cooling zone.