Energy Science and Technology > 3. Clean and Efficient Combustion Technology of Fossil Fuel
Draft Paper Accepted
智聪 李 / 华中科技大学；能源与动力工程学院；煤燃烧国家重点实验室
春 娄 / 华中科技大学；能源与动力工程学院；煤燃烧国家重点实验室
Oxy-combustion is a clean combustion technology that can reduce greenhouse emissions by increasing oxygen concentration and replacing N2 with CO2. This paper constructed a mechanism coupled with the OH*/CH*/C2*/CO2* formation and quenching reactions to simulate counterflow diffusion flames. Different stoichiometric mixed fraction (Zst = [1+(YFWOνO/YOWFνF)]-1) with the same adiabatic flame temperature (2279 K) was set by adjusting the CO2 concentration on the oxidant and fuel side. Soot formation and chemiluminescence were interpreted based on the carbon-to-oxygen (C/O) ratio space. Because compared with the physical space and the mixture fraction space, the C/O ratio space is not affected by boundary conditions and flame configuration. With Zst increases (0.064 to 0.4), the soot zone shrinks and moves toward the oxidant side, but chemiluminescence and temperature move in opposite directions. The peak temperature decreases by 50 K, while the soot volume fraction (SVF) decreases by 85% due to a significant decrease in the concentration of soot precursors (A1, etc.). The reduction of chemiluminescence is much lower than SVF, making chemiluminescence apparent in high Zst flames. In C/O ratio space, the soot precursor boundary starts at 0.50. Due to the high concentration of oxidizing components, A1 is almost non-existent at positions less than 0.5, the very low polycyclic aromatic hydrocarbons concentration is not conducive to soot formation. While the chemiluminescence is mainly distributed in the range of 0.45-0.55 between the radical pool (< 0.5) and the soot precursor zone (> 0.5), because the CH2, CH, and C2H produced by the oxidation of C2H2 are distributed here, which are the reactants producing chemiluminescence radicals.