The Production of Electrical and Thermal Energy from the Exhaust Gas Heat of Preheater Kilns

It is shown, by means of an example, i.e., a 1600-ton/day four-stage suspension preheater kiln of a cement factory, that the waste heat present in the exhaust gases can be converted into useful electrical and thermal energy. This is possible even though the exhaust gases are heavily loaded with dust. The heat recovery system installed in 1981/1982 in a Swiss cement plant and the respective production line are described in detail. A comprehensive explanation is given concerning the experience of the first operating year, the iqteraction of the new plant with the existing production facilities, and the current measured technical data. The performance limits for economic operation are explained and the decision criteria quoted. Further applications of the successfully tested heat recovery system can be expected wherever beat sources in the form of heavily loaded gases are available.