Flow distribution and jet behavior analysis of fabric filter's pulse-jet cleaning

摘要

Particulate Matter (PM) pollution is an alarming environmental problem and one of the most used PM control devices in industry is fabric filter, with a pulse-jet cleaning system. A better understanding of the flow behavior of such pulse-jets is essential to improve cleaning efficiency and diminish dust emissions. Therefore, the present study aims to analyze the flow patterns of the cleaning pulse of an industrial-scale bag filter, with high-pressure and low-pressure systems, using transient three-dimensional CFD simulations. The results show that the center bags in a row take slightly higher shares of air volume and the larger part of it is due to secondary flow. The simulations also give insights into the degree of centralization of the jets: misalignment is progressively reduced along the purge tube, being less pronounced in the high-pressure than in the low-pressure system. Although the mass flow is higher in the high-pressure system, the distribution of the flow among the bags is relatively uniform and similar for both systems. Implications: This work shows, through simulations, that the behaviour of the air pulse during the cleaning is not uniform. There is a variation of the pulse along the duct, due to the movement of the wave that is formed. Besides wave intensity and pressure, the position and shape of the cleaning nozzle also affects the air pulse.