Study On Combustion Characteristics And NO_x Emission Of Methane/Oxygen-Enriched Diffusion Flame

Oxygen-enriched combustion technology, which is high-efficiency and energy-saving, has many benefits, such as higher thermal efficiency, increased productivity, lower exhaust gas volume, and reduced equipment and raw material costs, etc. Recently, oxygen-enriched combustion has been gaining extensive development and application in a variety of industries such as metal manufacturing, glass melting, waste incineration, boiler combustion-surpporting, and ceramic kilns etc. However, NO_x emission will increase dramatically due to high combustion temperature. Based on numerical simulations of oxygen-enriched diffusion flames, the formation of NO_X in 30%-40% oxygen- enriched air combustion will be more than 4 times than that in air combustion. As one kind of major pollutants of atmosphere, a large amount of emission of NO_x, which is subjected to increasing stringent regulation, will restrict the oxygen-enriched combustion technology to fewer applications. So it's significant for the application of oxygen-enriched combustion to study the formation characteristics and suppression methods of NO_x in high-temperature oxygen-enriched combustion.There are many methods for reducing NO_x emission during combustion, such as staged combustion, flue gas recirculation, and steam injection and so on. The mechanisms of reducing NO_X of those methods are mostly based on decreasing flame temperature or avoiding the favorable ratio of air and fuel for NO_X formation, which are helpful for suppression of NO_X in oxygen-enriched combustion. However, high-efficiency and high-temperature are the supreme benefits of oxygen-enriched combustion, so it's necessary to investigate the NO_X suppression issue according to its characteristics. There are three major mechanisms of NO_X formation: thermal, prompt and fuel NO_X mechanisms, and different methods are adopted for different NO_X formation mechanisms. Therefore, the numerical simulation method with detailed elementary reaction kinetics including NO_X formation and experimental method are...