| OCR Text |
Show efficiency of fuel-rich flames was that at a specific equivalence ratio, parent hydrocarbon fuel persisted undissociated throughout the entire flame [16]. This fuel/air composition the limiting equivalence ratio, was that at which 0H,H, and 0 radical surpluses ceased to exist, and represented the stoichiometry at which flame instability and unburned hydrocarbon pollution became problems. In their study of low-Btu gas combustion, Martin and Dederick [11] suggested that a phenomenon, similar to the one just described, was taking place. Since they did not monitor radical concentrations, they could only deduce how the presence of CH, late in the flame affected radical pool concentration decay rates. This chemical behavior will be explored in greater detail in this program. The greatest concern about the use of coal-derived alternate syngases as replacements for natural gas stems from their potential to generate high levels of NO [8,9,11,12,14]. Previous theoretical [12] and experimental [11,14] studies have indicated that the NO pollution potential for syngases will greatly exceed that for natural gas. The proposed research will complement these preliminary studies by conducting both an experimental and theoretical program concerning the NO environmental aspects of alternate gas combustion. Low-, medium-, and high-Btu gas flames will be artificially synthesized in the laboratory and then doped with the nitrogenous species suspected to be the innate bad actor in syngas combustion, NH~ [8,9,12]. Because of the low adiabatic flame temperatures of syngases [14], NO emission from fuel-nitrogen oxidation is far greater than that from atmospheric (or parent-fuel) diatomic nitrogen. Physical and chemical microstructure analyses will be repeated with syngas flames containing quantities of NH that are typical of commericial coal-gasification processes [9,12]. In order to decipher the kinetics of NO pollutant formation and destruction in syngas flames, partial-equilibrium-state theory and dissociation efficiency will be modified to include the N-H-0 system. Research on NH-/02 flames [19,20] has demonstrated that N-H-0 radical pool behavior is analgous to that in C-H-0 flames [16]. Thus, NH~/0? flames serve as the basis for delineating fuel-nitrogen (NHo) chemical kinetics in syngas flames. Ai-11- |
