Comparative Study of Cu-SSZ-13 and V₂O₅-WO₃/TiO₂ Catalysts on Ammonia Storage and Slip Behavior

Area of Science:

• Catalysis
• Environmental Chemistry
• Chemical Engineering

Background:

• Selective Catalytic Reduction (SCR) is crucial for NOx emission control.
• Ammonia (NH3) storage and desorption are key factors in SCR catalyst performance.
• Understanding catalyst behavior under varying conditions is vital for optimizing emission control technologies.

Purpose of the Study:

• To compare the NH3 adsorption-desorption behavior of Cu-SSZ-13 and V2O5-WO3/TiO2 catalysts.
• To investigate the impact of temperature, space velocity, and NH3/NOx ratio on catalyst performance.
• To analyze the relationship between NH3 storage, NOx conversion, and N2O formation.

Main Methods:

• Utilized an NH3-SCR flow reactor to study adsorption-desorption.
• Systematically varied temperature, space velocity, and NH3/NOx ratios.
• Analyzed ammonia storage capacity, ammonia slip, NOx conversion, and N2O formation.

Main Results:

• Increased temperature and space velocity reduced NH3 storage capacity, promoting earlier ammonia slip.
• High NH3/NOx ratios and high space velocity (60,000 h-1) at 500 °C led to a 20-30% decrease in storage capacity and earlier slip.
• Higher NH3 storage enhanced NOx reduction, especially below 300 °C, but excessive storage increased N2O byproduct formation.
• Cu-SSZ-13 exhibited superior NH3 storage capacity and stability, less affected by operational changes, delaying ammonia slip compared to the vanadium-based catalyst.

Conclusions:

• Cu-SSZ-13 offers better performance and stability in NH3-SCR applications.
• Operational parameters significantly influence catalyst efficiency and ammonia slip.
• Careful control of NH3 storage is necessary to balance NOx conversion and minimize N2O emissions.