Removal of Combustion Originated Ultrafine Particles by Condensation Enlargement in Packed Column Scrubbers

Based on the principal of vapor phase change,an experimental study on particle size enlargement through vapor nucleation and condensation for effective removal of combustion originated ultrafine particles has been carried out in a packed column scrubber.The supersaturation vapor condition required by condensation growth of these particles was reached by changing the moisture content in inlet flue gas and the temperature difference between inlet gas and scrubbing water.The influence of different operating conditions,such as particle size distribution,temperature difference between inlet gas and scrubbing water,additive vapor mass flow rate and water-gas ratio etc.,on particle removal efficiency, has been investigated.Results show that the ultrafine particles resulting from combustion can be effectively separated in case the supersaturation state of flue gas is reached in the packed column scrubber.The particle removal efficiency rises with increasing temperature difference between inlet gas and water,as well as with rising water-gas ratio,which can reach 81% with an additive vapor flow rate of 0.08 kg/m~3 at a temperature difference of 50°C,while when the temperature difference keeps constant,this value may be highly improved by increasing the humidity of the inlet flue gas.