Molecular dynamics simulation on agglomeration and growth behavior of dust particles during flue gas filtration

High efficiency purification of dust particles contained in industrial flue gas is urgently needed to mitigate environmental pollution and improve waste heat recovery efficiency. The agglomeration and growth behavior of dust particles has significant effects on filtration efficiency of industrial flue gas. In this paper, in order to reveal the microscopic mechanism of dust particles agglomeration and growth, three kinds of typical components in industrial flue gas, such as steam (H2O), PAHs (naphthalene) and dust particles (SiO2) were selected to establish a molecular dynamics (MD) simulation system. The agglomeration behavior of dust particles and the formation and growth process of dust clusters were characterized by MD simulation. The effects of temperature, channel width, cooling rate and gas composition on the agglomeration behavior of dust particles and the growth of dust clusters were investigated. It is found that the formation and growth of dust clusters are driven by agglomeration of dust particles. The decrease of gas temperature, cooling rate and channel width can accelerate the agglomeration of dust particles and the growth of dust clusters, which is beneficial to dust particles filtration. In addition, the hydrogen bonds formed between the H2O molecules and SiO2 particles can promote the adsorption of SiO2 particles to the H2O molecules, which is also beneficial to the formation and growth of dust clusters. So increasing the content of steam in industrial flue gas is helpful to the growth of dust clusters and the filtration of dust particles.