THE NEW KILN PLANT IN THE BERNBURG WORKS OF E-SCHWENK-TEMENTWERKE-KG - CONCEPT AND OPERATING RESULTS

Between 1990 and 1992 all the old kiln plants at the Bernburg cement w orks were replaced by a new 5 000 t/d plant. This plant represents the logical implementation of a new plant concept which takes account of the latest cement process technology. The main features of the plant i nclude minimum consumption of thermal and electrical energy, optimum q uality and process control, a high degree of flexibility in the use of raw materials and fuels, and the capability of producing a large numb er of cement types of consistently high quality. The intention was als o to make a drastic improvement in the environmental situation around the cement works and to implement an ambitious architectural design fo r the buildings. A circular blending bed was installed for homogenizin g the raw materials from the quarry, and minimum fuel energy consumpti on was achieved by using the latest process technology (precalcination , 6-stage cyclone preheater, clinker cooler with intermediate crusher modern control system). The kiln exhaust gases and cooler exhaust air are fully utilized for drying not only the cement raw materials but al so the limestone meal and granulated blastfurnace slag. The NOx emissi ons have been lowered to comparatively favourable values by the use of precalcination. with tertiary air ducting and stepped combustion. Mea sures for reducing the SO2 emissions ns derived from the raw materials were also implemented successfully. The kiln plant is provided with a n alkali/chloride bypass to reduce the amount of recirculating materia l, and its carefully controlled operation ensures smooth kiln operatio n. A modern combined grinding system, consisting of high-pressure grin ding rolls, ball mill, and two separate classifiers, was installed for grinding the cement. This resulted in, a drastic reduction in electri cal power consumption when compared to the old plants. The use of a pr ocess control system and an automatic laboratory has led to a high deg ree of uninformity when changing over between types and to significant cost advantages.