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

Abstract

a b s t r a c tNanofibrous 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.

Regeneration of dust filters challenged with metallic nanoparticles: Influence of atmospheric aging

“…The greyscale images are then analysed to estimate the cleaned surface. The regeneration efficiency according to the residual pressure drop is calculated as follows (Hau and Leung, 2016):…”

Skin layer in cyclic loading-cleaning of a nanofiber filter in filtering nano-aerosols

“…When the pressure drop escalated to a maximum limit, loading was stopped and cleaning started. The pressure drop was monitored continuously until it reached a reasonable low value in which there was no further substantial decrease over time [9], then cleaning stopped and the next loading cycle began. The cycle was repeated for 5 more times with the pressure drop closely monitored.…”

“…The duration of pulse-jet, idle, and backblow were 0.5 s, 0.2 s and 10 s, respectively. These have been reported elsewhere in details [9]. Throughout the experiment, pressure drop across the filter and the flow rate were monitored by a digital pressure manometer and a flowmeter, respectively.…”

“…This is also analogous to the skin effect in liquid filtration [8]. When the filter pressure drop reaches an unacceptable level, backpulse and backblow can be used to clean the filter [9,10]. First, when a cake has already formed on the filter, the cake needs to be blown off first from the filter surface prior to blowing aerosols trapped inside the filter.…”

Electrospun polyacrylonitrile nanofiber membranes for air filtration application

“…The PFE of electrospun nanoiber membranes can be tuned by varying fiber morphology, diameter, transparency/thickness of membranes (Hau and Leung 2016;Jing et al 2016;Zhang et al 2016). Moreover, Leung et al (2009) compared microiber and nanoiber ilters and found that nanofiber membrane has high filtration efficiency than microiber.…”