燃瓦斯气蓄热式加热炉再燃低氮改造数值模拟

To realize nitric oxides(NO_x) emission regulation below 200mg/m³ (O₂ volume fraction at 3.5%) in heating furnace fired refining gas, a high efficiency low nitrogen reconstruction scheme by reburning technology was proposed, and it was confirmed by numerical calculation and industrial test. The software of FLUENT was applied to investigate the effects of reburn refining gas ratio and primary area stoichiometric ratio on the distribution of temperature and NO_x mass concentration at different sections, generation, reduction characteristics of NO_x and unburned rate of refining gas. According to the optimized numerical calculations, the reconstruction was implemented and industrial test was carried out for one week. The results showed that, with the reburn fuel ratio increasing, the proportion of high temperature space decreased, the amount of thermal NO_x reduced and reduction increased, the NO_x reduction efficiency by reburning impact firstly increased and then decreased. The highest NO_x reduction efficiency by reburning impact when the reburn fuel ratio was 0.20. Increasing the reburn fuel ratio and decreasing the primary area stoichiometric ratio could increase the NO_x reduction efficiency, but the unburned fuel ratio increased meanwhile. When the reburn fuel ratio between 0.15~0.20 and the primary area stoichiometric ratio between 1.15~0.20, the greatest and average values of NOx mass concentration were 160mg/m³ and 130mg/m³ (O₂ volume fraction at 3.5%) respectively.