空气分级下主燃区喷氨还原NOx实验研究

Experimental Study on NOx Reduction by Urea Injection in Primary Combustion Zone Based on Air Staging

通过在煤粉燃烧实验台上进行测试,研究了空气分级下主燃区喷氨还原NOx的特性规律及影响因素。结果表明:主燃区过量空气系数KSR1是影响NOx还原效果的关键因素,当KSR1≤0.85时,KSR1越大,NOx还原效果越好;强还原性气氛(KSR1=0.65)反而不利于NOx的还原,最佳工况为KSR1=0.85;当KSR1≤0.85时,温度越高则NOx还原效果越好;温度T为1 673 K时,NOx还原效率最高为42.66%;温度越高越利于燃烧中OH、H等中间产物的生成,这是在无氧条件下NH3还原NO的必要条件。

Experimental tests were carried out on a bench-scale combution system to study the characteristic law of NOx reduction by urea injection in the primary combustion zone based on air staging, while the key influencing factors were analyzed. Results show that the stoichiometric ratio KSR1 in the primary combustion zone is one of the key factors influencing the NOx reduction;in the case of KSR1 being less than or equal to 0.85, the higher the KSR1 is, the better the NOx reduction effectiveness will be;high reduction atomphere(KSR1=0.65) is on the contrary not benefitial to the NOx reduction;the optimal KSR1 for NOx reduction is 0.85;when the KSR1 is less than or equal to 0.85, the higher the temperature is, the better the NOx reduction effectiveness will be;the maximum NOx reduction efficiency reaches 42.66% at the temperature of 1 673 K. High temperature benefits the generation of intermediate products OH and H in the combustion process, which is the necessary condition for NOx reduction with NH3 in the absence of oxygen.