O&k Orenstein & Koppel Aktiengesellschaft

Wolfgang Buslowski

Hans-Dietmar Maury

Bernold Kraft

A method for the heat treatment of finely granular material, particularly for the manufacture of cement, employs a preferably multi-stage cyclone preheater (2), a rotary tubular kiln (1), a cooler (6) and a kiln off-gas line (5) which is formed between rotary tubular kiln (1) and cyclone preheater (2). The off-gas lines provides a passage substantially in upward direction for the off-gases of the rotary tubular kiln (1) and receives tertiary air fed thereto for the combustion of additional fuel. The tertiary air is provided in two streams from the cooler (6), which cooler is connected behind the rotary tubular (1) on the material side, the streams being introduced into the kiln off-gas line (5) at different heights. In order to separate the combustion of the additional fuel from the precalcination and to avoid the production of injurious nitrogen oxides (NO.sub.x), the additional fuel is fed exclusively to the lower partial stream of the tertiary air in such a manner that sub-stoichiometric combustion take place before the entrance of the second partial stream of tertiary air. The second partial stream of tertiary air effects a complete combustion of the additional fuel in the upper part of the kiln off-gas line (5).

Method for the heat treatment of finely granular material

A method for the heat treatment of finely granular material, particularly for the production of cement, employs a multi-stage cyclone preheater, a rotary tubular kiln, a cooler, and a single kiln off-gas line which is formed between the rotary tubular kiln and the cyclone preheater and is flown through substantially in upward direction by the off-gasses of the rotary kiln and to which tertiary air is fed in two partial-streams for the combustion of additional fuel. The method employs steps of feeding fuel to a lower partial stream of tertiary air, directing material to be treated above a second partial stream of tertiary air, and applying precalcined material in countercurrent with the off-gas line below the tertiary air.

In order to create a technically more effective and more economical method of decontamination by which complete decomposition of all injurious substances is obtained in simple fashion, it is proposed, in connection with a method and a plant for the treatment of contaminated soils, that the drying can be combined in a mill passed through by hot gases with a crushing of the material to a particle size of 0 to 10 mm, that after the drying the material, together with the gaseous phase, be treated in the form of a solid/gas dispersion in a heating and decontamination path with burner, with a temperature within the range of 800.degree. C. to 1200.degree. C. and then be separated in a cyclone separator stage from the gaseous phase which contains all injurious substances, said phase being recycled with the burner for the complete decomposition of the injurious substances, a partial stream of the combustion gases being fed to the combined drying and comminuting stage and the purified solids being removed after a cooling the cooling air of which is fed to the burner as preheated primary air.

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Ennigerloh, Germany

Wolfgang Buslowski