A wet process of PM2.5 removal from industrial waste gases was proposed

with cooling and condensation in the axial channel of a spiral plate exchanger. The characteristics of thermo-phoresis and diffusion-phoresis of PM2.5 with vapor component in the boundary layer of heat and mass transfer were pointed out. A pseudo-homogeneous model was built based on the mechanism on dust removal by condensate film absorption. Subsequently

the attenuation function of PM2.5 concentration was deduced. The dust removal efficiency equation

with the condensate flux nw and the waste gas inlet velocity u0 as the variables

was obtained. Parameters in the model were derived by means of analogies of momentum

heat and mass transfer

and verified with the experimental data of cooling and condensation under constant wall temperatures. It is shown that the key factor is the vapor diffusion volume flux (or called PM2.5 diffusion-phoresis velocity) Vw with the magnitude of 20—40 mm·s-1.