关键词: 选择性催化还原, 烟道气, 蜂窝催化剂, 低温, 失活

Abstract:

The researches on low temperature denitrification catalysts in China are mainly focused on laboratory scale test. On the other hand, the researches on the denitrification activity and poisoning mechanism of non-vanadium low-temperature NH₃-SCR (selective catalytic reduction) honeycomb catalyst under coal-fired flue gas conditions were insufficient, and the experiments with simulated flue gas cannot fully reflect the performance of the catalyst under real flue gas. A self-designed low-temperature NH₃-SCR device was used in the pilot test at a thermal power plant in Shihezi. The optimal process conditions of the catalyst under actual flue gas were obtained, and the influence mechanism of complex components on the catalyst was analyzed in-depth. The results showed that the catalyst had the best denitration efficiency when the SO₂ concentration was below 35mg/m³, the space velocity was about 4200h^-1, the flue gas temperature was about 100℃ and the ammonia nitrogen ratio was about 1.2. High concentration of SO₂ will promote the formation of sulfates and the sulfation of the active components in the catalyst. The low-temperature denitration process and catalyst have broad industrial application prospects because the process is easy to modify and the low-temperature denitration catalyst is environment-friendly and shows excellent denitration performance and sulfur resistance.

Key words: selective catalytic reduction (SCR), flue gas, honeycomb catalyst, low temperature, deactivation