燃煤电厂SCR脱硝氨逃逸迁移规律试验研究

研究了某燃煤电厂350 MW机组SCR系统氨逃逸在下游设备的迁移规律。现场试验发现，SCR系统下游设备中空气预热器、低低温省煤器、电除尘器氨逃逸捕获率分别为总氨逃逸量的23%~26%、9%~17%和56%~62%，进入脱硫系统的氨逃逸不足总氨逃逸的3%；提高低低温省煤器出口烟温会导致氨捕获率降低，但下游电除尘器飞灰氨含量增多，表明其对氨的捕获性能提高，最终总的捕获比例基本保持不变。通过现场试验及数据分析，建立了电除尘器所捕捉飞灰中氨含量与SCR出口氨逃逸的对应关系，当机组燃煤煤质大幅变化或对设备进行大幅改造等情况时，需要根据实际情况重新修正对应关系。

Test Study on the Migration Characteristics of Slip Ammonia from the SCR System in the Coal-Fired Power Plant

In this paper, the migration characteristics of slip ammonia were studied which passed through the various downstream equipments of the SCR system of a 350 MW coal-fired power plant. The field test concludes that the slip ammonia intercepted by the air pre-heater, low temperature economizer, and electrostatic precipitator accounts for 23%~26%, 9%~17%, and 56%~62% of the total slip ammonia, respectively, while that entering the desulfurization system accounts for less than 3% of the total slip ammonia. Raising the temperature of the low temperature economizer outlet flue gas will reduce its capture ratio of ammonia. However, the increase of the ammonia content in the fly ash from the electrostatic precipitator indicates the performance improvement of the electrostatic precipitator for the ammonia capture capability. Therefore, the overall capture ratio remains basically unchanged. Through the field test and data analysis, the relationship between the ammonia content in the fly ash from the electrostatic precipitation and the ammonia escape from the SCR outlet was also established. Nevertheless, whenever there are any significant coal quality changes or equipment modifications, etc., such relationship needs to be revised according to the actual situations.