Number Simulation of Heterogeneous Condensation of Water Vapor on Fine Particles in Growth Tube by Population Balance Model

Abstract

The emission of fine particles produced in coal combustion had been causing serious environmental and health problems. The heterogeneous condensation of water vapor on fine particles as a preconditioning technique for the removal of fine particles from flue gas is very promising in the future which has been proved by many works. This investigation adopted the k-epsilon turbulence model coupled with the population balance model（PBM）to simulate the performance of heterogeneous condensation of water vapor on fine particles in a growth tube. The supersaturation vapor environment can be achieved by adding water vapor in the inlet of the growth tube. The simulation results show that the particle growth is related to the distribution of the supersaturation in the growth tube. When the supersaturation is not enough, the particles stop growing. This agrees with the experiments that has been implemented previously. The effect of gas velocity and the concentration of the fine particles were analysed as well. The flue gas velocity decreasing will lead to the increasing of flue gas residence time in the growth tube. The high residence time is favourable for particle growth. As the initial particle concentration increases, the effect of particle growth is more obvious under the given supersaturation environment.