A process and device separate off a volatile component from the off-gases in cement clinker production. Raw materials for cement clinker production are passed through a preheater with heat exchange with the off-gases and are then burnt in a rotary kiln. Owing to the heating in the preheater, the volatile component bound in the raw materials is vaporized and separated off. A first raw material stream having a relatively high concentration of the volatile component is applied to a first line of the preheater and a second raw material stream having a lower concentration of the volatile component is applied to a second line. The volatile component is separated off from the first substream of the off-gases. The first raw material stream heated to a temperature of at least 250 C. with the first substream of the off gases in the first line is combined with the second raw material stream.

It is described an integrated process for the production of clinker by dry process, with treatment in continuous of by-pass dusts produced by the kiln, wherein the solid matter to treat consists of bypass dusts of a clinker production process, containing compounds of chloride, sodium, potassium and sulphur, such a process comprising the following steps: a) extraction of the bypass dusts directly from the phase of quench, without intermediate storage, at a temperature comprised between 150 and 200 C., with a moisture content varying from 0.1 to 3% by weight, preferably from 0.1 to 0.5% by weight, and with a quantity of calcium carbonate lower than 55% by weight; b) mixing of said dusts coming from step a), within a maximum time comprised between 2 and 10 minutes, preferably lower than about 5 minutes, with water up to a water/dusts ratio varying from 2:1 to 4:1, preferably from 2.5:1 to 3.5:1, in a way to obtain a mixture with a moisture content comprised between 45 and 75% by weight, preferably between 50% and 55% by weight, even more preferably equal to about 50% by weight; c) mechanical stirring of the mixture diluted up to complete dissolution of the soluble salts; d) mechanical separation of the mixture so diluted in a liquid fraction containing water and soluble salts and in a solid fraction in form of cake or crust.

In methods of and/or plants for manufacturing cement clinker, the amount of chloride bypass exhaust gas 79 can be substantially decreased, when using previously cooled chloride bypass exhaust gas 81 and/or cooled kiln exhaust gas as coolant for the chloride bypass exhaust gas 39 prior to deducting the chloride bypass exhaust gas 39.

Disclosed is a bypass system for use with off gases that have exited a cement kiln utilized in a cement making process. The bypass system is adapted to remove both NOx and volatile components that are present in the off gases while the off gases are in the bypass duct.

A process and device separate off a volatile component from the off-gases in cement clinker production. Raw materials for cement clinker production are passed through a preheater with heat exchange with the off-gases and are then burnt in a rotary kiln. Owing to the heating in the preheater, the volatile component bound in the raw materials is vaporized and separated off. A first raw material stream having a relatively high concentration of the volatile component is applied to a first line of the preheater and a second raw material stream having a lower concentration of the volatile component is applied to a second line. The volatile component is separated off from the first substream of the off-gases. The first raw material stream heated to a temperature of at least 250 C. with the first substream of the off gases in the first line is combined with the second raw material stream.

A process and device separate off a volatile component from the off-gases in cement clinker production. Raw materials for cement clinker production are passed through a preheater with heat exchange with the off-gases and are then burnt in a rotary kiln. Owing to the heating in the preheater, the volatile component bound in the raw materials is vaporized and separated off. A first raw material stream having a relatively high concentration of the volatile component is applied to a first line of the preheater and a second raw material stream having a lower concentration of the volatile component is applied to a second line. The volatile component is separated off from the first substream of the off-gases. The first raw material stream heated to a temperature of at least 250 C. with the first substream of the off gases in the first line is combined with the second raw material stream.

To produce cement clinker by baking of raw meal in a kiln, use is conventionally made of a raw meal preheater in which the heat of the flue gas emerging from the kiln is transferred to the raw meal. In order to remove impurities which accumulate in circulation between the kiln and the raw meal preheater, a part of the flue gas is extracted from the kiln, bypassing the raw meal preheater. The heat generated during the baking of cement clinker can be used particularly efficiently if the flue gases extracted and diverted past the raw meal preheater are used in a boiler to generate hot steam which can subsequently be expanded in a turbine.

Methods for the heat treatment of a material flow and the cleaning of resulting exhaust gases are disclosed. The material flow may be preheated in a preheating zone, burned in a sintering zone, and cooled in a cooling zone. Exhaust gases of the sintering zone may flow through a preheater and be used for preheating the material flow. The exhaust gases leaving the preheater may be cooled at least partially in a comminuting device in interconnected operation or at least partially in a cooling device in direct operation. Exhaust gases may then be at least partly dedusted in a dust filter. A temperature of the dedusted exhaust gas may then be raised before the exhaust gas is cleaned of pollutants in at least one catalyst. A temperature at which the exhaust gases flow through the catalyst in direct operation may be higher, at least in phases, than a temperature at which the exhaust gases flow through the catalyst in interconnected operation.

Methods for the heat treatment of a material flow and the cleaning of resulting exhaust gases are disclosed. The material flow may be preheated in a preheating zone, burned in a sintering zone, and cooled in a cooling zone. Exhaust gases of the sintering zone may flow through a preheater and be used for preheating the material flow. The exhaust gases leaving the preheater may be cooled at least partially in a comminuting device in interconnected operation or at least partially in a cooling device in direct operation. Exhaust gases may then be at least partly dedusted in a dust filter. A temperature of the dedusted exhaust gas may then be raised before the exhaust gas is cleaned of pollutants in at least one catalyst. A temperature at which the exhaust gases flow through the catalyst in direct operation may be higher, at least in phases, than a temperature at which the exhaust gases flow through the catalyst in interconnected operation.

Method for the purification of exhaust gas from the production of cement clinker in a rotary kiln, in which raw materials are ground in a mill to form raw meal, raw meal is preheated in countercurrent in a preheater with exhaust gas from the rotary kiln and optionally precalcined, preheated and optionally precalcined raw meal is supplied to the rotary kiln and burned in the rotary kiln to form cement, the exhaust gas from the rotary kiln is denitrified before entering the preheater of a selective non-catalytic nitrogen oxide reduction with a reagent which provides ammonia, and wherein, according to the invention, the exhaust gas from the preheater is subjected to gas conditioning and catalytic oxidation of ammonia. The object is further solved by means of a device for gas conditioning and catalytic oxidation which is arranged between the preheater and the mill.