Estudo da eficiência da poliimida aromática como meio filtrante em um filtro de mangas para processo de sinterização de uma indústria siderúrgica

Abstract

Air contamination with substances harmful to health or the environment, has grown since the Industrial Revolution. Due to the threat to human health, such as cardiorespiratory diseases and, in the worst cases, deaths, arose the need to control emissions of air pollutants. Currently, environmental laws which define the maximum emission parameters are more stringent and public agencies which inspect companies and industries are more active. Researches are carried out in different parts of the world with the aim of optimizing and implementing technologies that promote reduction of air pollutants and their respective negative impacts. One equipment widely used in industry is bag filter, with the function of separating solid particles in suspension from gases to be emitted into atmosphere. Bag filter, which is a fabric filter, has high collection efficiency for a wide particle size range and can be applied with different filter materials. The choice of the fabric is made based on characteristics of particulate material and gas stream, since it is necessary to have compatibility of the filter medium with the effluent to be treated. Aromatic polyimide (PI) is widely used as a filter medium in steel industries, for the dedusting of sintering. The present work focuses on the characterization and analysis of collection efficiency of the filter medium composed of aromatic polyimide fibers with a telphon support screen, for filtration of gas containing powder from the primary sintering process. Initially, characterization of particulate material was carried out and then characterization of the filtering medium. After this, thirty filtration cycles were performed, in duplicate, until the maximum pressure drop of 100mmH2O was reached, then cleaning with a reverse air pulse of 5 bar for 60ms. The equipment used is based on the VDI 3926 standard, simulating an industrial bag filter on a laboratory scale. From the analysis of the results obtained, it was observed that aromatic polyimide has high particle collection efficiency for filtering particulate material derived from the sintering process in steel industry, with 99.68% efficiency in the 1st cycle and 99, 83% in the 30th cycle. However, cleaning the filter was not efficient, with partial cleaning occurring and variation in residual pressure drop.