Study on removal effect of suspended particulate matter by humidity swing air cleaning method

A humidity swing air cleaning method has been studied experimentally for improving a SPM (suspended particulate matter) removal effect. This method uses humidity swing of the air with evaporation of water and condensation of moisture, and removes the SPM by making a nuclear condensation with the SPM as nuclei and gravitational settling of the grown droplet. According to our previous study, the SPM removal effect of 90 % level was obtained at humidity swing of 0.2 kg/kgDA at flow rate of 5 L/min. The purpose of this study is to improve the SPM removal performance, especially in a high flow rate conditions. We have tested two ways; one is a modification of the dehumidifier geometry for promoting the nuclear condensation effect and the gravitational sedimentation effect. The other is an introduction of an inertial impaction as the grown droplets removal method using a coarse mesh filter as an obstacle in the fast flow condition. The geometry changes of the dehumidifier made the improvement in removal ratio up to 99.9% level at the flow rate of 5 L/min. Moreover, the introduction of the mesh filter resulted in the same removal ratio of 99.9% level at a fast flow condition of 10 L/min.