On the rate constants of OH + HO2 and HO2+ HO2: A comprehensive study of H2O2 thermal decomposition using multi-species laser absorption

• DOI: 10.1016/j.proci.2012.06.108
• Publication Date: 2012-07-19T06:00:28Z
• Authors: Zekai Hong; King-Yiu Lam; Ritobrata Sur; Shengkai Wang; David F. Davidson; Ronald K. Hanson
• Keywords: 02 engineering and technology; 0204 chemical engineering; 7. Clean energy

Abstract Hydrogen peroxide (H 2 O 2 ) and hydroperoxy (HO 2 ) reactions present in the H 2 O 2 thermal decomposition system are important in combustion kinetics. H 2 O 2 thermal decomposition has been studied behind reflected shock waves using H 2 O and OH diagnostics in previous studies (Hong et al. (2009) [9] and Hong et al. (2010) [6,8]) to determine the rate constants of two major reactions: H 2 O 2 + M → 2OH + M ( k 1 ) and OH + H 2 O 2 → H 2 O + HO 2 ( k 2 ). With the addition of a third diagnostic for HO 2 at 227 nm, the H 2 O 2 thermal decomposition system can be comprehensively characterized for the first time. Specifically, the rate constants of two remaining major reactions in the system, OH + HO 2 → H 2 O + O 2 ( k 3 ) and HO 2 + HO 2 → H 2 O 2 + O 2 ( k 4 ) can be determined with high-fidelity. No strong temperature dependency was found between 1072 and 1283 K for the rate constant of OH + HO 2 → H 2 O + O 2 , which can be expressed by the combination of two Arrhenius forms: k 3 = 7.0 × 10 12 exp(550/ T ) + 4.5 × 10 14 exp(−5500/ T ) [cm 3 mol −1 s −1 ]. The rate constants of reaction HO 2 + HO 2 → H 2 O 2 + O 2 determined agree very well with those reported by Kappel et al. (2002) [5]; the recommendation therefore remains unchanged: k 4 = 1.0 × 10 14 exp(−5556/ T ) + 1.9 × 10 11+ exp(709/ T ) [cm 3 mol −1 s −1 ]. All the tests were performed near 1.7 atm.