USE OF A HYBRID FILTER IN A BASIC OXYGEN STEEL PLANT

Objective. The basic oxygen steel plant of Krupp Hoesch Stahl AG in Do rtmund-Horde has a primary and a secondary off-gas collection and dedu sting system. The secondary dedusting system has been modernised to im prove the level of pollution control. It is the first time that ''hybr id filter'' technology has been used in this respect in a steel plant of this magnitude. Documented in the following are the results that ha ve been achieved. Summary. The hybrid filter differs from wet-type ele ctrostatic precipitators in that only the dust collecting electrodes a re continually wet with a film of running water. If an adequate distri bution of water and an almost identical pressure ratio on both sides o f the flexible collecting electrodes are ensured, then the new filter system fulfills the requirements in hand better than conventional equi pment of this type. It has been possible, for example, to reduce the r esidual dust content in the cleaned gas by an average of 70%. Furtherm ore, within the scope of the structural and technical measures, the no ise level has been decreased and the diffuse fuse dust emissions lesse ned by an increased volumetric now rate during extraction. It has also been possible to reduce the number of safety-related filter shutdowns from once or twice per day to approximately once per month.