Synthesis of fly ash-based SAPO-34 molecular sieve denitration catalyst and its denitration performance

The fly ash-based SAPO-34 microporous molecular sieve was prepared using the fly ash from the Zhungeer Power Plant in Inner Mongolia as the raw material and the acid-base combined method. Using SAPO-34 molecular sieve as carrier, ammonium carbonate as ammonium salt and copper nitrate as copper source, Cu-SAPO-34 molecular sieve catalysts with different Cu loadings were prepared by ion exchange method. After aging treatment at 500℃, 8% H2O/N2 atmosphere, the selective catalytic reduction denitrification performance and physical and chemical characteristics of the catalyst were tested and analyzed. The results show that the SCR activity is closely related to the species of Cu. The isolated Cu2+ at the ion exchange site is the main active center of the Cu-SAPO-34 catalyst in the NH3-SCR reaction. With the increase of Cu loading, the catalyst’s The low temperature SCR activity increases, while the high temperature activity reaches the highest when the Cu mass fraction reaches 1.50% and then decreases. 1.50 Cu-SAPO-34 catalyst can reach a NOx conversion rate of more than 80% in the range of space velocity up to 200,000h−1, 350~500℃, showing a wide denitration temperature window. The article points out that the catalyst is more suitable for high temperature conditions than the vanadium-titanium catalyst due to its better high temperature activity and anti-sintering ability. This work opened up a new way for the harmless treatment of fly ash from coal-fired power plants to prepare SCR catalysts.