过量空气系数、热负荷及反应物混合模式对天然气锅炉柔和燃烧特性影响

Effects of Excess Air Coefficient, Heat Load and Mixing Pattern of Reactants on MILD Combustion Applied to Natural Gas Boilers

柔和燃烧(MILD)因其NOx排放低、节约能源和燃烧稳定的特点,有望成为新一代天然气锅炉燃烧技术。文中以成分97%为CH_4的天然气为燃料,基于额定蒸发量为1t/h的天然气锅炉的实际运行工况,研究了过量空气系数φ从1.05~1.45,热负荷P从600~786k W不同工况下的预混和扩散方式柔和燃烧特性。试验结果表明,柔和燃烧条件下,过量空气系数增加,NO和CO排放降低。满负荷下,预混柔和燃烧NO排放仅为54mg/m^3@3.5%O_2,远低于传统旋流扩散燃烧方式天然气锅炉的NO排放(111mg/m^3@3.5%O_2)。

Moderate ＆ intense low oxygen dilution （MILD） combustion is a well known measure to reduce NOx emission, save energy and enhance flame stability. As an advanced combustion technology, MILD is expected to be an option for future gas boiler combustion technology. This paper studied premixed and non-premixed MILD combustion based on 1t/h gas boiler. The experiment was operated with excess air coefficient varying from 1.05 to 1.45, and heat load varying from 600-786kW. NO/CO emissions are deduced with excess air coefficient. NO emissions （54mg/m^3@3.5%O2） of premixed MILD combustion are greatly reduced compared with the NO emissions （111mg/m^3@3.5%02） of swirling diffusion combustion.