Khd Humboldt Wedag Ag

Khd Humboldt Wedag Gmbh

Khd Humbolt Wedag Gmbh

Norbert Streit

Carsten Eckert

Ralf Filges

Horst Schilling

Andreas Hand

Hans-Wilhelm Meyer

Stephan Kuhnke

Marc Feiss

Matthias Mersmann

A method for operating a plant for producing cement clinker from raw meal having, as viewed in the materials flow direction, at least one calciner for deacidifying the raw meal, and at least one rotary kiln for sintering the deacidified raw meal to form cement clinker. The deacidified raw meal, after passing through the calciner, flows via a cyclone preheating stage into the rotary kiln. Exhaust gases are guided from the rotary kiln into a reactor, arranged between the rotary kiln and the calciner, with fuel being fed into the reactor superstoichiometrically in relation to the dwell time of the exhaust gases in the reactor, so that carbon dioxide in the exhaust gases is reduced to form carbon monoxide. The carbon monoxide is used as a reducing agent for nitrogen oxides, which are chemically reduced in the reactor independently of the short dwell time in the calciner.

Method for operating a plant for producing cement

The aim of the invention is to create a bypass system for a cement clinker production line, which is characterized by particularly low investment costs and operating costs, thus being economically favorable. Said aim is achieved by installing the bypass system in such a way that the capacity of pre-existing system filters such as the main exhaust gas filter and/or the cooler exhaust filter can also be used for treating the bypass gas flow.

Cement clinker production comprising partial removal of a flow of rotary kiln exhaust gas containing harmful substances

Cement clinker production apparatus having a precalcination stage connected upstream of a rotary kiln, in which precalcination stage a CO-containing reduction zone in the rotary kiln off-gas duct is employed for the purpose of reducing the pollutant NO . In order to make certain that the quantitative ratio of O in the rotary kiln off-gas to fuel admitted by a deNO burner, and thus control the effectiveness of NO reduction, a pivoting throttle valve ( ) is positioned in the precalcination stage to control the quantity of rotary kiln off-gas and thus the O content in the kiln off-gas. The throttle valve ( ) is positioned in the rotary kiln off-gas duct ( ) above the deNO burner ( ), above the raw meal inlet ( ), and before the confluence of the tertiary air substream with the rotary kiln off gas. The throttle valve ( ) is pivotable about an articulation ( ) at the bottom side of the valve so that the flow of the rotary kiln off-gas remains laminar, thus enhancing the reaction length of the CO-containing reduction zone ( ).

Apparatus for thermal processing of raw material in meal form

A system for the manufacture of cement clinker from cement raw meal in which the off-gases of the cement clinker production line not only undergo denitrification but also undergo desulfurization, so that even sulfur-rich raw materials and fuels can be employed without exceeding the prevailing pollutant emission limits. A substream of the oversize material ( ) discharged from the mixing chamber ( ) of the precalcination stage ( ) as solid sorbent may be combined with the off-gas ( ) and/or with a partial gas discharge ( ) of the rotary kiln off-gas in order to convert the sulfur oxides contained in those off-gases to calcium sulfate ( ), which is subsequently separated from the system off-gas.

Method for desulfurization of off-gases of a system for the manufacture of cement clinker

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Siegburg, Germany

Norbert Streit