Direct conversion of NO and SO₂ in flue gas into fertilizer using ammonia and ozone

This study focused on the simultaneous removal of NO and SO₂ from an industrial flue gas stream. To evaluate the removal efficiency of NO and SO₂ using O₃ and NH₃, the consumption of two reactants (O₃ and NH₃) in line with the conversion of NO and SO₂ was quantified experimentally. In addition, NO and SO₂ were converted to valuable fertilizers, NH₄NO₃ and (NH₄)₂SO₄. To identify a principle strategy to enhance the generation of fertilizer, Fourier transform infrared spectroscopy was used to examine the reaction mechanisms for the formation of NH₄NO₃ and (NH₄)₂SO₄. Acceleration of SO₂ oxidation could be achieved effectively by adding NO to a gas mixture of SO₂, NH₃, and O₃. The formation of HNO₃ might be enhanced by the simultaneous feeding of NO and SO₂. Particle generation was also 10 times higher for NH₃/(NO + SO₂) than for NH₃/NO and for NH₃/SO₂, which is a prominent feature of this study. Moreover, the introduction of steam had a positive influence on particle generation. This method offers dual applications for NO and SO₂ removal from a flue gas stream and direct fertilizer generation.