Heterogeneous Condensation of Water Vapor on Fine SiO2 Particles in Two-Section Growth Tube

Vapor condensation on submicron particles is a promising pretechnique to remove fine particles. For effectively enhanced particle growth, the study of particle amplification by heterogeneous condensation in the two-section growth tube (TGT) was presented. Additionally, the supersaturated fields in TGT were also predicted and evaluated. This moderated growth tube is described as a warm wet-walled tube in the first section, followed by the warmer-walled (method 1) and cold-walled regions (method 2). And, the major component of particles from coal combustion SiO2 was tested. The experimental results indicate that the particle enlargement is obviously improved from both methods in TGT. Compared with both methods, it is worth noting that when the lower temperature level is presented in the first section, the warmer extended section is beneficial to the improvement of particle growth. Moreover, for the higher temperature of the first section, the facilitated particle enlargement is favored by the cold water in the second section. Additionally, a flatter supersaturated environment could be achieved for method 2 in TGT. With the increase of temperature in the first section, the improvement of peak supersaturation is weakened for method 1 in TGT. However, the opposite conclusion of peak supersaturation enhancement is obtained for method 2.