Experimental and Kinetic Studies of Chemical Role of CO<sub>2</sub> in Hydrocarbon Oxidation during Fuel-Rich O<sub>2</sub>/CO<sub>2</sub> Combustion

DOI Web Site BIBCODE 参考文献9件
  • WATANABE Hirotatsu
    Department of Mechanical and Control Engineering, Graduate School of Engineering, Tokyo Institute of Technology
  • KIATPANACHART Dejudom
    Department of Mechanical and Control Engineering, Graduate School of Engineering, Tokyo Institute of Technology
  • OKAZAKI Ken
    Department of Mechanical and Control Engineering, Graduate School of Engineering, Tokyo Institute of Technology

抄録

Experimental and kinetic studies of the chemical role of CO2 in hydrocarbon reactions were conducted in a fuel-rich CH4 flat flame with air ratios varying from 0.60 to 0.74. Unburned hydrocarbons (CH4, C2H2, C2H4, and C2H6) in O2/CO2 combustion were found to be lower than those in air combustion. The differences in the CH4 oxidation characteristics between the air and O2/CO2 combustion were caused by the chemical role of CO2 in the reaction R1 (CO2 + H → CO + OH), R2 (CH2(S) + CO2 → CH2O + CO), and higher third body efficiencies of CO2 at an air ratio (λ) = 0.62 where the concentrations of reactants were high. The role of CO2 in R1, R2, and the higher third body efficiencies of CO2 decreased the rate of CH4 oxidation during the early stage of combustion, where O2 was present. Even though R2 did not directly compete with the main chain branching reaction R3 (H + O2 → H + OH) for H radicals, like R1 did, R2 changed the hydrocarbon reaction pathway, thereby decreasing the rate of R4 (CH3 + HO2 → CH3O + OH) which had negative sensitivity in CH4 oxidation. However, we found that R1 and R2 advance CH4 oxidation in the last stage of combustion where O2 was mostly consumed. This is attributed to the fact that the reactions R1 and R2 were able to advance without the presence of O2, and that R1 produced OH radicals that were active in hydrocarbon oxidation in the specific temperature range and R2 enhanced hydrocarbon oxidation when the rate of R4 was insignificant. Although R1 was the dominant reaction to reduce unburned hydrocarbons in the O2/CO2 combustion, the role of R2 was significant at λ = 0.62. Meanwhile, when the air ratio was 0.74 where concentrations of reactants were relatively low, the chemical role of CO2 is to only decrease the rate of CH4 oxidation due to the presence of an excessive amount of O2.

収録刊行物

参考文献 (9)*注記

もっと見る

関連プロジェクト

もっと見る

キーワード

詳細情報 詳細情報について

問題の指摘

ページトップへ