Improving the removal of SO3 aerosol by combining flue gas condensation and alkali spray

A novel technology involving phase-transition and dehumidification is proposed in this paper to efficiently and economically remove SO3 aerosol. A SO3 aerosol removal system (ARS) is developed by combining flue gas condensation and alkali spray based on this technology. The phase-transition process and spray field are simulated by CFD models. The influence of key operating parameters on removal performance, water and heat recovery capacity are evaluated experimentally. Furthermore, the technical economy is analyzed. The results showed that the new system had better removal performance than single heat exchanger. More heat and water can be recovered when the temperature drop increases, and most atomized alkaline solution also can be collected. In addition, the removal efficiency increases with the increase of the spray amount of the alkaline solution and the flue gas temperature drop. The removal performance of NaOH is the best among sodium-based sorbents. But the difference in the removal efficiencies between different sorbents is small. Besides, spray before heat exchanger is prove to be the optimal coupling mode of two technologies. Finally, the results of economic evaluation indicate that the proposed method also has good economic performance and the capital costs can be recovered in approximately 2.5 years.