Effect of Intermediate Radicals on NO<sub>x</sub> and De‐NO<sub>x</sub> Characteristics of NH<sub>3</sub>/H<sub>2</sub>/Air Flames at High Pressure
Anand Singh, Debojit Sharma, Sukanta Kumar Dash, Mahendra Reddy Vanteru
Abstract
Abstract The effect of NH, NH 2 , and HNO on NO x and De‐NO x chemistry of a NH 3 /H 2 /air mixture at a pressure of 20 bar is investigated. Results suggest that the increase in pressure reduces NO x emissions and increases HO 2 radical production through the reaction H + O 2 (+M) → HO 2 (+M). In contrast with OH and O radicals, the HO 2 radical is less reactive, which prevents NO formation. The fuel‐bound NO x emissions mainly depend on the reactions NH + OH → NO + H, HNO(+M) → NO + H(+M), HNO + OH → NO + H 2 O, and HNO + O 2 → NO + HO 2 , and thermal NO x depends on the reactions N + O 2 → NO + N and N + OH → NO + H. At a pressure of 20 bar, the N 2 O is further converted to NO 2 and N 2 through the reaction N 2 O + NO → NO 2 + N 2 . The abundance of HO 2 radicals at high pressure also initiates the conversion of NO to NO 2 via the reaction NO + HO 2 → NO 2 + H.