Simulation and optimization of the particle agglomeration in an aerodynamic agglomerator using a CFD–PBM coupled model

Abstract

As an effective method to remove fine particulate matter (FPM) in coal-fired industries, the aerodynamic agglomeration has recently received increasing attention due to its application value. In this paper, a CFD–PBM coupled model of the particle agglomeration for industrial application was developed to predict the particle size distributions (PSDs) using Eulerian multiphase approach and Population Balance Model. Three kinds of particles with different inertia (i.e. inertialess, finite inertial, and inertial) and Brownian motion were considered, and a collision efficiency was induced to modify the kernel functions. Furthermore, the impacts of inlet velocity, initial particle concentration and flow field on the PSDs and the agglomeration efficiency were investigated. The results show that the agglomeration efficiencies of particulate matters with aerodynamic diameter [Formula: see text] 2.5[Formula: see text][Formula: see text]m and [Formula: see text] 10[Formula: see text][Formula: see text]m (i.e. PM[Formula: see text] and PM[Formula: see text]) both present logarithmic curves with the inlet velocity or the initial particle concentration. Under the working condition of the calculation, the optimal inlet velocity is in the range of 11–15[Formula: see text]m[Formula: see text][Formula: see text][Formula: see text]s[Formula: see text], and the optimal agglomeration efficiency of [Formula: see text] and [Formula: see text] is about 40%. The aerodynamic agglomerator is suitable for the traditional coal-fired power plants and cement plants, but it is not recommended when the initial particle concentration is less than 16.9[Formula: see text]g[Formula: see text][Formula: see text][Formula: see text]m[Formula: see text]. The analysis of the flow field shows that the longitudinal edge of the vortex and the windward side of the vortex generator are the main regions where particles agglomerate.