Efficient Reduction of PM 10 / PN 2.5 emissions at Iron Ore Sinter Plants: S 2/3

Iron ore sinter plants are major sources of PM10 / 2.5 emissions. Typical off-gas flows of sinter machines are in the range of 500.000 to 2.000.000 m³ (STP) per hour and emission limits for dust are usually 50 mg/m³ (STP). Annual operation hours above 8400 together with the high amount of PM 10 / 2.5 in the emitted dust result in PM 10 / 2.5 emissions of a typical sinter plant operated in compliance with actual dust emission limits of 200 – 800 tons per year. The emission limit for dust in the TA-Luft (2002) has been reduced to 20 mg/m³ (STP). In the IPPC document “Best Available Techniques Reference Document on the Production of Iron and Steel” (2001) fabric filters installed downstream of electrostatic precipitators are considered as one possible BAT technique for off-gas cleaning of sinter plants. The special properties of dust from sinter plants, in particular the small size of the particles, require careful attention with regard to the selection of fabric filter material. The results of extensive tests on fabric filter materials for sinter plant off-gas cleaning at an industrial scale are presented. Ageing of different fabric material was characterised by break strength, pressure drop and infiltration of fabric material with dust were investigated in long-term tests. Considerable differences regarding expectable service time of filter bags were found.