Design improvement of an injection pipe and its validation on the performances of a semi-industrial pulse-jet baghouse

Résumé et principaux résultats

Article dans la revue Process Safety and Environmental Protection n°165 (2022).
The purpose of this study is to improve the operation of a pulse-jet baghouse by the modification of the design of its compressed air injection pipe. The base injection pipe has all the nozzles of constant diameter (9.7 mm). To characterise the injection pipe, experimental measurements and three dimensional CFD simulations were carried out. The impact of the geometry of the injection pipe on the behaviour of an instrumented filter bag moved under the nozzles has been assessed from experimental measurements. Once the design of a new injection pipe has been defined by three dimensional CFD simulation and assessed by measurements, the performances of a semiindustrial pulse-jet baghouse has been measured with both the base and the modified injection pipes. The main conclusion of our study is that in order to ensure that cleaning of filter bags belonging to the same injection pipe is more homogeneous, it is not enough to assess the injection pipe (by measurements and/or calculation) but it is also necessary to characterize the behaviour of a filter bag moved under and along the nozzles of the injection pipe. The results of our study show that a new injection pipe geometry with decreasing nozzle diameter (from 10.5 mm at the inlet to 8.0 mm at the bottom of the pipe) allows a more uniform behaviour of the instrumented filter bag moved under and along the pipe. This better uniformity is characterized by both the average peak pressure and the average root mean square acceleration averaged along the height of the filter bag. Finally, when operated with the modified injection pipes, the semi-industrial pulse-jet baghouse shows better performances characterized by lower residual pressure drop after cleaning (-8 %), longer filtration cycles (+70 %) and lower particle emissions (-5 % for PM1, -15 % for PM2.5 and -18 % for PM10).