Experimental And Numerical Study Of Laminar Flame Speed Of Propane And Syngas In O₂/CO₂ And O₂/H₂O Atmosphere

As the global warming becomes increasingly serious, the carbon capture and storage(CCS) technology has become one focus in terms of the utilization of the fossil fuel. As a novel combustion mode without obvious technical obstacle, the O xy-fuel combustion is considered the most promising CCS technology for industrial application. According to the diluting gases in the furnace, Oxy- fuel combustion can be divided into O2/CO2 and O2/H2 O oxy-combustion. For the differences in physical and chemical properties among CO2?H2O and N2, the flame characteristic of O xy-fuel combustion has great change with the normal combustion. As a basic characteristic of flame, the laminar flame speed plays an important role in the understanding of the fundamental phenomena and interpreting the chemical reaction mechanism in the combustion process, thereby, it can provide theoretical basis for the development of combustion technology and the design of combustion equipment. So the research on the laminar flame speed in O2/CO2 and O2/H2 O atmosphere is of great importance for the research and development of O xy- fuel technology.The laminar flame speeds of C3H8/O2/CO2 mixtures in oxygen-enrich conditions were measured by using the PIV measured system on the self-design counter- flow flame configuration, and the chemical effects of CO2 on flame propagation were analyzed by the numerical simulation. The research re sults show that the laminar flame speed decreases obviously with the increase of CO2 concentration in the mixtures; the forward reaction of the elementary reaction CO+OH=CO2+H is suppressed by the chemical effects of CO2, thus leading to the reduction of the produced H radicals; the decrease of the reaction rate of H+O2=O+OH further decreases the concentration of O H and O radicals and makes the reduction of the overall reaction rate, which leading to the decrease of laminar flame speed.As a supplement for the available reaction mechanism, an optimized H2/CO kinetic model with 12 elements and 40 reactions contained was proposed and validated in this paper. The laminar flame speed of H2/CO/O2/H2 O in oxygen-enrich condition was investigated by the optimized mechanism and the chemical effects of steam on flame propagation was analyzed by the chemical kinetics. The results indicate that there is a large reduction on flame speed with the increase of H2 O fraction; As an overall consequence, the existence of H2 O seriously enhances the reaction rate of H2+O2+H2O=HO2+H2O, and H+O2=O+OH is weakened for the competition of H radical with H2+O2+H2O=HO2+H2O, which cause H transfer to more stable HO2 and H2 O. The total reaction rate is suppressed and lead to the decrease of laminar flame speed.