Improving the removal of inhalable particles by combining flue gas condensation and acoustic agglomeration

In order to develop the high efficiency and cost-effective particle removal technology, a novel particle removal unit combined flue gas condensation and acoustic agglomeration was designed based on theoretical analysis. The performance of the designed combined particle removal unit was evaluated by the laboratory scale experiments. Compared with the single external field of sound or condensation, the combination of the two external fields made the removal efficiency higher. The maximum total removal efficiency could be up to 70% when the sound frequency was 1500 Hz, the sound pressure level (SPL) was 141 dB, and the cooling water flow rate was 560 L/h. With the increase of flue gas temperature drop, the removal efficiency increased. In addition, more waste water and heat could be recovered from the flue gas. There was an optimal sound frequency range of 1500–2000 Hz for the combined particle removal unit, and the removal efficiency decreased whether the sound frequency increased or decreased. The removal efficiency increased with the rise of SPL, but the considerable improvement was obtained only when the SPL exceeded 120 dB. Therefore, there was an SPL threshold for the application of combined particle removal unit. Through the techno-economic comparisons with other technologies, the novel particle removal unit was proved to be a highly efficient and cost-effective particle removal technology.