关键词: TUD-DNS3, 重油催化裂化, 烟气, NO_x, 加注方案, SO_x, 硫转移, 脱硝助剂

Abstract:

Starting from June 1, 2023, the NO_x emission limit of catalytic cracking catalyst regeneration flue gas in Yangpu Economic Development Zone has been reduced from 200 mg/m³ to 100 mg/m³. A certain enterprise conducted industrial application tests of TUD-DNS3 denitration additive to avoid excessive NO_x emissions from flue gas. After adding the denitration agent, the mass concentration of NO_x in the flue gas steadily decreased. When the cumulative amount of the agent reached about 2.5% of the total catalyst storage in the system, the mass concentration of NO_x at the outlet of the comprehensive tower decreased from 135 mg/m³ to 92 mg/m³, and the removal rate reached over 30%. The wear index of TUD-DNS3 was 1.78%, and the wear index of fresh catalyst was 2.1%. The difference in wear index between the two was not significant, as the concentration of smoke dust and solid content of oil slurry remained basically unchanged before and after the addition of additives. When the mass concentration of SO₂ in the discharged flue gas remains basically unchanged, the alkali consumption for desulfurization and denitrification decreased by about 2 t/d, and the hydrogen sulfide content in the gas product increased, indicating that TUD-DNS3 had a certain sulfur transfer effect. After the addition of TUD-DNS3, the CO/CO₂ ratio in the regenerated flue gas decreased from 0.367 to 0.238. The heat load on the regeneration side increased, and the steam generation of the external heat exchanger increased by about 17 t/h. While the furnace temperature of the waste heat boiler remained stable, the fuel gas consumption of the waste heat boiler increased.

Key words: TUD-DNS3, heavy oil catalytic cracking, flue gas, NO_x, refueling plan, SO_x, sulfur transfer, denitrification additives