|
|
|
| Study on the Deactivation Behaviour of Low Temperature SCR Denitration Catalysts |
| Feng Beibei1， Yin Rixin2， Hu Mengyu1
|
| 1 CNBM Equipment Group, Hefei Cement Research & Design Institute Co., Ltd. , Hefei Anhui 230051, China; 2 Anhui Huasu Co., Ltd. , Chuzhou Anhui 239000, China |
|
|
|
|
Abstract The medium and low-temperature NH3-SCR technology has been maturely applied in the range of 180℃ to 420℃, and is currently expanding from the cement industry into the steel industry. To meet the demands for energy conservation and reduced consumption, there is an urgent need for in-depth research into the actual operational behaviour of low-temperature SCR catalysts (<180℃). This paper takes SCR catalysts from a lime kiln at a certain steelworks which had been in operation for half a year as the subject of study. Catalysts characterization analysis and activity tests were conducted using techniques such as XRF, XRD, SEM-EDS, BET, TG and TPSR to investigate the deactivation mechanisms and the feasibility of regeneration. The results indicate that catalyst deactivation is primarily attributable to the coupled effects of carbon deposition and the accumulation of ammonium bisulfate and ammonium nitrate; the carbon deposits exist in the form of graphitic carbon. These deposits block the pore channels, leading to a significant reduction in the specific surface area and pore volume of the catalysts. Combined TG-DSC and TPSR analysis revealed that the deactivated catalyst exhibited significant weight loss between 350℃ and 500℃, with the maximum decomposition rate occurring near 440℃. This process comprised three stages: low-temperature dehydration, medium-temperature CO desorption, and high-temperature oxidation of carbon deposits and decomposition of ammonium salts. The decomposition of ammonium salts was the dominant process, and the overall reaction exhibited endothermic characteristics. Activity test results show that the deactivated catalyst must operate at temperatures above 250℃ to meet the emission limit of NOX, while effective oxidation of carbon deposits and decomposition of ammonium salts requires temperatures above 400℃. Consequently, on-site thermal regeneration is energy-intensive and not feasible. This study provides a reference for the prevention and control of deactivation, as well as the engineering application of low-temperature SCR catalysts in complex operating conditions within industries such as the cement industry.
|
|
Received: 20 January 2026
Published: 25 September 2026
|
|
|
|
|
|
|
|
