Investigation into water vapor and flue gas temperatures on the separation capability of a novel cyclone separator

Abstract

Using water mist or vapor to help collect fine particles has been attracting increasing attention. A new fine particle separation technology which combines the centrifugal force field with the supersaturated vapor is recently proposed to realize the high removal efficiency of PM2.5 in gas cyclones. Different from the operation of a traditional cyclone, in this new cyclone, the operational temperature can be a key variable that determines the particle condensational growth and the related separation efficiency, which has not been studied in cyclones. Therefore, this paper investigates the effect of the temperatures in such purification process. Both the temperatures of the water vapor and the flue gas are studied. The effects of the two temperatures on the performance of the cyclone are studied in terms of the overall removal efficiencies, grade removal efficiencies and the morphology change of the dust particles by SEM. Additionally, the experimental results are analyzed based on the classical heterogeneous nucleation theories. The results indicate that higher water vapor temperature can improve the removal through decreasing the surface tension, which makes the particles easier to nucleate and grow in size. On the contrary, higher flue gas temperature leads to a decrease in efficiency, because the saturation deceases although the nucleation rate and critical supersaturation for particle nucleation shows conducive to nucleation.