Whole life cycle performance evolution of selective catalytic reduction catalyst in coal-fired power plants

Four typical coal-fired power plants were employed to explore the performance evolution within the whole life cycle of catalysts. The results revealed that the amount of active ingredients in the catalysts decreased over time. The content of V2O5 and WO3 in four units had decreased by 3.32%-32.8% and 12.9%-22.9% respectively. However, alkali metals and alkaline earth metals in flue gas were gradually deposited on the catalyst and led to catalyst poisoning, especially in two units due to arsenic poisoning. The specific surface area of catalysts decreased significantly in the first year of operation, accounting for 87.3%, 47.8%, 55.1% and 86.7% of the decline in the lifetime, which may be the main reason for the decline of catalyst activity during this period. The wall thickness of catalysts decreased linearly with the operation time in the lifetime. The relative activity of catalysts at the end of designed service lifetime was between 0.90 and 0.93, whereas the decrease range of SO2/ SO3 conversion rate was within 15.4%-35.6%. Influenced by the catalyst design and the variations of practical operation conditions, the difference between the actual and designed service lifetimes of catalysts in the four units was 2.08%, 44.0%, 4.17%, and 25.0%, respectively.