Plant upgrade with the Köppern 2-Stage Koesep – a combined air classifier for High Pressure Grinding Rolls applications
T. Hanstein, F. Kleemann, Köppern Aufbereitungstechnik GmbH & Co. KG, Freiberg, E. de Weldige, Maschinenfabrik Köppern GmbH & Co. KG, Hattingen, Germany
High Pressure Grinding Rolls (HPGR) have been used in comminution applications for more than 30 years. Today, one of the most efficient grinding technologies for cement production is the use of this grinding system operating in the semi-finish grinding mode. Thereby, savings of specific energy consumption in a range of 20 to 40 % can be achieved, compared to grinding circuits using a ball mill in closed circuit with a dynamic air classifier. At the same time the plant capacity increases drastically, depending on the grinding system and the size of the High Pressure Grinding Rolls. Hence, upgrading of cement grinding systems offers significant process and commercial benefits. So far one of the major disadvantages of cement grinding with HPGR in the semi-finish grinding mode was frequently the necessity of using two types of air classifiers with a high space requirement. Maschinenfabrik Köppern is one of the market leaders in manufacturing and supply of roller presses for comminution, compaction and briquetting. One of their latest developments is a compact air classifier for HPGR applications. With the 2-Stage Koesep air classifier the HPGR can be used in the semi-finish or even in the finish grinding mode operating with only one combined air classifier and a ball mill. The construction height of the 2-Stage Koesep air classifier is much lower compared to most of the previously known classifying systems. It combines a static and a dynamic classifying stage in one housing with a compact design. Within the static stage, the grinding material coming from the HPGR is deagglomerated and coarse particles are separated for regrinding. The fine material together with the separation air reaches the dynamic high efficiency stage for fine separation into final product and rejects. This material can be fed either to the ball mill only or partly to the HPGR and ball mill. Due to its compact design the 2-Stage Koesep air classifier is well suited for modernisations of existing grinding plants. An Austrian cement producer in close cooperation with Köppern upgraded its grinding system with this new combined classifier. Installation and commissioning was done during ongoing operation with a plant downtime of 40 h only. Results and experiences of this upgrade are discussed.
Summary CEMENT INTERNATIONAL 01/2017 pp 34-39
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