Removal of fine and ultrafine particles by means of a condensational growth assisted bubble column

The paper shows experimental findings aimed to prove the effectiveness of a concept design for fine and ultrafine particle capture called condensational growth assisted bubble column. Experiments were carried out with a gas at ambient temperature and pressure polluted with calibrated polystyrene nanoparticles (mean numeric diameter 113 nm, standard deviation 120 nm). The laboratory scale equipment included the sequence of a growth tube and a bubble column. In the growth tube, the heterogeneous condensation of water vapour took place over the particles, producing a liquid-solid aerosol of size larger than the original particles. Experiments showed that the condensational growth pre-treatment improved the bubble column removal efficiency from nearly 25 % up to 90 %. The growth tube also contributed to particle capture so that the overall system reached particle removal efficiency above 95 %. The particle removal efficiency of the entire unit was higher than the sum of the single growth tube and bubble column contributions, suggesting the occurrence of favourable synergic effect between them.