Experimental study on acoustic agglomeration of ultrafine ash particulate matter under various environmental conditions

Abstract

Climate change and environmental pollution are closely linked and have recently become a major challenge not only for Lithuania but also for societies around the world. Currently, the most promising technology for removing ultrafine particulate matter (UFPM) from the exhaust gas of stationary fossil fuel and biomass combustion boilers is electrostatic precipitators, which effectively trap UFPM larger than 2.0 μm in diameter, while the removal efficiency for smaller particles is very low [1]. Acoustic agglomeration is the agglomeration and growth of fine particulate matter in exhaust gas into larger particles by sound waves of high intensity and frequency [2, 3]. UFPM penetrate deep into the human respiratory tract and can therefore have significant effects on human health. The efficiency of conventional devices in removing UFPM is quite low. Therefore, it is crucial to develop technologies for primary removal of UFPM before the electrostatic precipitator (ESP). This paper was aimed at investigating the effects of a newly developed acoustic flow generator for the acoustic agglomeration of particles, which incorporates a number of improvements in its design, on the effect of grazing waves on the agglomeration of ash particulate matter. The use of an acoustic flow generator in combination with the ESP increases the separation efficiency of UFPM.