(Effect of hydrophilicity of dust particles on their removal efficiency in a gas cyclone with atomized water vapor)

In this paper, the effect of hydrophilicity of dust particles on their removal efficiency in a gas cyclone with atomized water vapor was studied by experiments. The water vapor was generated by electro-acoustic transducing ultrasonic atomization technique. Several kinds of industrial dust with different hydrophilicities were injected in the cyclone and their removal efficiencies were measured and compared. The results showed generally the removal efficiency will increase with water vapor added to the cyclone. Such increase will be more significant for more hydrophilic dust particles. The removal efficiency of the talcum powder increased from 76.9% to 90.1% by 13.2% when 4 g•m-3 vapor was added. However, for the S-zorb desulfurization catalyst with poorer hydrophilicity, the increase was only 8.0% with the same amount of vapor. The effect of hydrophilicity was especially manifested in fine particles with diameter about 2.5 μm. The highest increase of the removal efficiency of the talcum powder appeared at particle size 2 μm, which was from 31.5% to 72.8% with 4 g•m-3 vapor added,while the highest increase of that of the S-zorb desulfurization catalyst was only from 43.9% to 61.6% at particle size 2.3 μm. Moreover, the dust particles before and after the cyclonewere examined by scanning electron microscopy (SEM) images, and the results confirmed the hydrophilicity has a significant impact on the agglomeration and growth of particles, which should be responsible for the difference in the removal efficiency of different particles. These studies could help optimize and improve the cloud-air-purifying (CAP) technology that combines gas cyclone with atomized water vapor technologies, and extend its versatility to industrial applications for decreasing the emission of PM2.5