Plasma-assisted chemical process for NOx control

Plasma-assisted chemical processes have been investigated for the control of NO_x flue gas emissions. Previous results have shown that nonthermal plasma is able to oxidize NO to NO₂, but cannot convert NO₂ to N₂ effectively. Rather, part of the NO₂ is converted to form N₂O and HNO ₃ (or NO₃^-). Several hydrocarbon additives, catalysts, and water film combined with the nonthermal plasma process have been investigated to enhance NO_x reduction, but NO_x reduction has been limited to the 70% range. As an alternative technology, the plasma-assisted chemical process was developed: plasma reactor to convert NO to NO₂, and the chemical reduction process to convert NO₂ to N₂, with minimum byproducts. The barrier dielectric packed-bed reactor followed by the chemical reactor was able to achieve nearly 100% NO_x decomposition with an extremely low power level (14 W/ft ³/min, 30 J/L, or 40 eV/molecule) and minimum N₂O formation. The power consumption becomes 30 J/L, 14 W/ft³/min, or 40 eV, which amounts to $299/t of NO, and the operating cost for the chemical reactor is $1448/t. The total cost is $1747/t, which is at least 20 times more economical compared to the conventional NO_x control technologies