Verringerung von Dioxinemissionen aus Sinteranlagen

Iron-ore sinter plants, according to studies conducted in the years from 1992 to 1995 by the steel industry and the German Federal Environmental Agency, generated during this period a specific PCDF/D emission of 1-4 #mu#g I-TEQ/t sinter and accounted for around 95% of all the dioxin emitted in iron and steel making in the Federal Republic. Following theoretical investigations and extensive practical preliminary trials on a semi-industrial and industrial scale, various European sinter plant operators have joined together as a working group to test and demonstrate the practicability of the entrained flow process incorporating downstream catalytic oxidation. The demonstration facility was set up at a sinter strand with a suction area of 150 m"2 operated by Thyssen Krupp Stahl AG in Duisburg. By adding lignite coke, a mean separation efficiency of 70% and PCDF/D mass concentrations between 0.13 and 0.76 ng I-TEQ/m"3 in the clean gas were achieved in the adsorption stage. Safety aspects received special consideration when the facility was built and the trials were conducted. The half-yearly trials using an oxidative catalytic converter revealed a sharp drop in catalytic activity, which was attributed to the surface of the catalytic converter becoming coated with hydrocarbons. The separation efficiency of the catalytic converter fell in the course of the trials from over 60% (when new) to the point of ineffectiveness. It has so far not been possible to achieve the target value of 0.1 ng I-TEQ/m"3. The trials with other adsorbents to increase the effectiveness of the adsorption stage will be continued upon completion of the current project. (orig.)SIGLEAvailable from TIB Hannover: RO 2148(20050) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Umwelt, Naturschutz und Reaktorsicherheit, Bonn (Germany)DEGerman