SCR脱硝系统最低连续喷氨温度的研究

目前国内选择性催化还原（SCR）脱硝机组普遍存在低负荷停止喷氨的问题，脱硝装置停运工况所对应的烟气温度称之为最低连续喷氨温度。出于技术保护的目的，以往引进国外技术的催化剂制造商得不到此温度的计算方法。为此，从硫酸氢铵（NH4HSO4）的生成机理出发，分析了NH4HSO4的结露过程，并结合催化剂的微孔毛细管冷凝现象，提出了一种计算最低连续喷氨温度的方法，该方法计算结果与工程实践有很好的耦合度。同时，根据烟气成分、脱硝效率、NOx入口浓度对最低连续喷氨温度的影响，结合运行经验，提出了“欠氨运行”概念，用以指导工程实践和脱硝系统的运行。

Study on Minimum Continuous-Operation Temperature of SCR System

Currently, most SCR systems cannot be operated under low loading conditions due to the low temperature of the flue gas. The temperature threshold at which the SCR is no longer operable is defined as the minimum continuous-operation temperature. However, the calculation method of this temperature is unavailable from the foreign catalyst technology supplier for confidentiality reasons. Therefore, this paper proposes a method to calculate the minimum continuous-operation temperature based on the ammonium bisulfate(ABS) generating mechanism and dewing process as well as the theory of capillary condensation. The calculation result of this method shows good consistency with the practical data. In addition, considering the influences of flue gas composition, de-NOx efficiency, and inlet NOx concentration on the minimum continous-operation temperature, this paper also puts forward the concept of inadequate operation to guide the daily operation of the SCR system for power plants.