Abstract In this study, the fuel-rich combustion of methane in a two-layer porous media burner with Al2O3 pellets of different diameters was experimentally investigated. The upstream layer consisted of 2.5-mm diameter packed Al2O3 pellets, and the downstream layer consisted of 5-mm, 6.5-mm, 7.5-mm, and 9.5-mm diameter packed Al2O3 pellets. The effects of pellet diameter on the temperature distribution, exhaust composition, and the syngas energy conversion efficiencies were studied at a fixed operation condition with an equivalence ratio of 1.6 and a gas velocity of 0.13 m/s. An optimal downstream pellet diameter of 7.5 mm was determined for the partial oxidation of methane corresponding to the highest syngas energy conversion efficiency. Stabilized methane fuel-rich flames were realized in the optimized burner for various gas velocities (0.09 m/s–0.15 m/s) and equivalence ratios (1.2–1.7). The effects of operation conditions (gas velocities and equivalence ratios) on the combustion performance were also tested. We found that 50.0% of the methane was converted to H2 and CO at an equivalence ratio of 1.7 and an inlet gas velocity of 0.15 m/s with burner energy conversion efficiency based on lower heating values.

中文翻译：

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具有不同直径的 Al 2 O 3 球团的两层多孔介质燃烧器中的甲烷部分氧化

摘要 在这项研究中，实验研究了甲烷在两层多孔介质燃烧器中不同直径的 Al2O3 球团的富燃料燃烧。上游层由直径为 2.5 毫米的氧化铝颗粒组成，下游层由直径为 5 毫米、6.5 毫米、7.5 毫米和 9.5 毫米的氧化铝颗粒组成。在当量比为 1.6 和气速为 0.13 m/s 的固定操作条件下，研究了球团直径对温度分布、废气成分和合成气能量转换效率的影响。确定了 7.5 毫米的最佳下游球团直径，用于部分氧化甲烷，对应于最高的合成气能量转换效率。在优化的燃烧器中实现了稳定的富含甲烷燃料的火焰，适用于各种气体速度 (0. 09 m/s–0.15 m/s) 和当量比 (1.2–1.7)。还测试了操作条件（气体速度和当量比）对燃烧性能的影响。我们发现 50.0% 的甲烷以 1.7 的当量比和 0.15 m/s 的入口气体速度转化为 H2 和 CO，燃烧器能量转化效率基于较低的热值。