掺氢天然气在燃气锅炉和灶具中的回火风险分析

掺氢天然气随已有管网输送到用户燃烧利用，是低成本大规模利用氢能的方式之一。掺氢比变化会影响燃烧设备运行参数，使设备回火特性发生变化。因此，本文定义参数β定量比较预混气体未燃侧流速和火焰传播速度的变化幅度大小，以表征设备回火风险。通过实验数据校核，当β < 0.6时，实际燃烧设备发生回火的风险显著增加；掺氢后燃气灶具（0.2 < β < 1）相比于预混的燃气锅炉（0.95 < β < 1.4）更容易发生回火，维持其安全运行所耐受的掺氢比更低。

FLASHBACK RISK ANALYSIS OF HYDROGEN-ENRICHED NATURAL GAS IN BOILERS AND DOMESTIC APPLIANCES

Blending hydrogen into natural gas in a certain proportion and transporting it through the existing natural gas pipeline network to end-users for combustion application is regarded as one of the potential ways to use hydrogen on a large scale at a low cost. However, the variation of the hydrogen blending ratio will affect the operating parameters of combustion devices. As a result, the flashback characteristics will change, threatening the operational safety. In the present study, a parameter β was defined to quantitatively compare the flow rate of the fresh premixed gas and the flame speed to characterize the risk of flashback. Verified using experimental data, the risk of flashback significantly increased when the β value was lower than 0.6. Moreover, results showed that flashback was more likely to occur in domestic appliances (0.2 $< $ β $< $ 1) than in gas boilers (0.95 $< $ β $< $ 1.4), and the available hydrogen blending ratio to maintain the safety of the former was lower.