Avaliação de meios filtrantes para filtro de mangas com sistema de limpeza de jato de ar pulsante do processo de despoeiramento secundário da aciaria de uma indústria siderúrgica

Abstract

Nowadays, in addition to complying with the emission limits determined by the authorities, some companies seek to minimize their operating costs. In order to achieve this, they must choose a proper material for the filter media, taking into account characteristics of the gas (mass flow, temperature and corrosivity) and the particulate matter (hygroscopy, abrasiveness and size). It is also necessary that the filter has extended span life and operate with low pressure drop and high collection efficiency for fine particles. So, this study aims to evaluate PTFE coated and non-coated polyester filter media of two manufacturers that can be employed in the secondary dedusting system of the LD process of a steel mill, a pulse jet fabric filter. In this way, first the particulate matter collected in the industrial baghouse and the filter medias were characterized. Then filtration experiments were conducted in a VDI 3926 based test rig which simulates a real pulse jet fabric filter. The penetration of particles in the media was calculated for the first filtration cycle, and the collection efficiency of PM2.5 and PM1,0 was determined before and after the cycles. Also, the collection efficiency of NaCl nanoparticles was calculated for the virgin filter medias in the 10 to 300 nm range. Experimental results of the first filtration cycle show that fabrics from manufacturer B had lower total filtration time and higher weight gain than the competitor, but its non PTFE coated version was the one that particles penetrated the most. On the other hand, the non PTFE coated polyester media of manufacturer A took more time than the one of manufacturer B to complete 20 cycles, and was more efficient in collecting particles before and after the cycles. And the PTFE coated media showed near 100% collection efficiency for PM2.5, PM1.0 and nanoparticles for both manufacturers.