CO对选择性非催化还原脱硝工艺影响的试验研究和模拟

Experimental Study and Simulation on Effect of CO on Selective Non-catalytic Reduction Denitration Process

在自行设计的选择性非催化还原(SNCR)脱硝试验台上,通过在还原剂中添加CO,研究了CO对SNCR脱硝工艺的影响,并利用Chemkin 4.1软件对试验工况进行了模拟.结果表明:改进型TB系列喷嘴采用中心逆喷方式可大大增强还原气体与主烟气的混合效果,明显优于工业上常用的侧喷方式,且不存在还原剂的催化分解问题;添加CO可使SNCR工艺的反应温度窗口降低并变宽;在低于875℃的条件下,添加CO有助于提高NOx的脱除效率,随着CO添加量的增加,既定温度下NOx的脱除效率先提高后降低,且随着温度的降低,达到NOx的最大脱除效率所需的CO添加量增大;添加CO可大大减少氨的泄漏量.通过对反应机理中的部分反应进行修正,使得模拟结果与试验结果基本一致.

The effect of CO on selective non-catalytic reduction （SNCR） denitration process was studied on a self-designed SNCR denitrating test rig by adding CO into the reductants. The software Chemkin 4.1 was used to simulate the test conditions. Results show that the improved TB serial nozzles which use cen- tral counter injection method can greatly increase the mixing effect of reducing gas with main flue gas. The central counter injection method is obviously better than the side injection method which is commonly used in industry, and no such problem as catalytic decomposition of reductant exists. Addition of CO can lower and widen the reaction temperature window of SNCR process. When temperature is lower than 875 ~C, ad- dition of CO is conducive to the increase of removal efficiency of NOx. With the increase of CO addition, the removal efficiency of NOx at given temperature rises at first and then decreases. With the decrease of temperature, the required CO addition for maximum removal efficiency of NOx increases. Addition of CO can greatly reduce the leakage of ammonia. After the parameters of part of the reactions are modified, the simulated results basiclly agree with the eaperimental results.