Experimental investigation of backpulse and backblow cleaning of nanofiber filter loaded with nano-aerosols

Abstract

Nanofibrous filter have been proven effective to remove nano-aerosols with size less than 100 nm. Cleaning is required after long-term use; however, very little has been published on the subject. An experimental investigation has been launched to determine backpulse, backblow and combined backpulse–backblow on cleaning of a loaded nanofiber filter. Nylon 6 nanofiber filters were loaded with polydispersed NaCl particles, 60% < 100 nm and 90% < 160 nm, generated from an aerosol generator. Air jets in form of backpulse, backblow and their combined mode were used to clean a loaded filter. During cleaning, the filter cake was removed first for which the pressure drop across the loaded filter decreased rapidly, followed by loosely attached aerosols in the filter being removed with finite pressure drop reduction at a reasonable rate, ending in the final stage for which much lesser aerosols were being removed. Ultimately, the filter reached a residual pressure drop which was higher than that of the initial clean filter indicating residual aerosols were trapped both in the cake heel and filter. Backpulse has been found to be more effective in removing the cake from the filter surface, whereas backblow provides an added advantage of removing by convection of the detached aerosols away from the filter preventing recapture. The synergistic combination of backpulse–backblow provides the best cleaning performance of a nanofibrous filter loaded with nano-aerosols.