Plasma-assisted chemical process for NO/sub x/ control

Plasma-assisted chemical processes have been investigated for the control of NO/sub x/ flue gas emissions. Previous results have shown that nonthermal plasma is able to oxidize NO to NO/sub 2/, but cannot convert NO/sub 2/ to N/sub 2/ effectively. Rather, part of the NO/sub 2/ is converted to form N/sub 2/O and HNO/sub 3/ (or NO/sub 3//sup -/). Several hydrocarbon additives, catalysts, and water film combined with the nonthermal plasma process have been investigated to enhance NO/sub x/ reduction, but NO/sub 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 NO/sub 2/, and the chemical reduction process to convert NO/sub 2/ to N/sub 2/, with minimum byproducts. The barrier dielectric packed-bed reactor followed by the chemical reactor was able to achieve nearly 100% NO/sub x/ decomposition with an extremely low power level (14 W/ft/sup 3//min, 30 J/L, or 40 eV/molecule) and minimum N/sub 2/O formation. The power consumption becomes 30 J/L, 14 W/ft/sup 3//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/sub x/ control technologies.