Related Experiment Video
Updated: Jun 3, 2026

Fabrication and Testing of Catalytic Aerogels Prepared Via Rapid Supercritical Extraction
Published on: August 31, 2018
Optimization of internals for Selective Catalytic Reduction (SCR) for NO removal
Zhigang Lei1, Cuiping Wen, Biaohua Chen
1State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology , Box 266, Beijing, 100029, China.
Optimizing selective catalytic reduction (SCR) systems involves strategic internal design. Specific ammonia injection grid nozzle sizes and catalyst layer spacing significantly improve ammonia (NH3) mixing and control slip, enhancing SCR efficiency.
Area of Science:
- Chemical Engineering
- Environmental Science
Background:
- Controlling ammonia (NH3) slip is crucial for selective catalytic reduction (SCR) system efficiency.
- Internal design elements significantly impact mixing performance and NH3 distribution within SCR systems.
Purpose of the Study:
- To investigate the relationship between SCR system internals and ammonia mixing performance.
- To identify optimal configurations for ammonia injection grids (AIG) and catalyst layer spacing to minimize NH3 slip.
Main Methods:
- Computational analysis of flow-guided internals in the SCR flow section.
- Investigation of AIGs with varying nozzle diameters (1.0 mm, 1.5 mm, 2.0 mm, and mixed).
- Evaluation of catalyst layer spacing effects on gas mixing in the SCR reactor section for different catalyst types (honeycomb, plate-type parallel, plate-type cross).
Main Results:
- Flow-guided internals improve velocity distribution but can negatively affect NH3 concentration uniformity.
- An AIG with mixed nozzle diameters (1.0 mm and 1.5 mm) demonstrated superior NH3 concentration distribution uniformity.
- Optimal spacing between catalyst layers varied by type: 100 mm (honeycomb), 1000 mm (plate-type parallel), and 12 mm (plate-type cross).
Conclusions:
- AIG design with mixed nozzle diameters is key for uniform NH3 distribution.
- Cross-channel arrangement of plate-type catalysts is more effective for reactor volume reduction compared to parallel arrangements.
- Strategic internal design, including AIG configuration and catalyst spacing, is vital for efficient SCR operation and NH3 slip control.
More Related Videos
Related Concept Videos
Turnover Number and Catalytic Efficiency
Chymotrypsin is a pancreatic enzyme that breaks down proteins during digestion. The...
Heterogeneous Catalysis
Reduction of Alkenes: Asymmetric Catalytic Hydrogenation
The metal catalyst used can be either heterogeneous or homogeneous. When hydrogenation of an alkene generates a chiral center, a pair of enantiomeric products is expected to form. However, an enantiomeric excess of one of the products can be facilitated using an enantioselective reaction or an...
Reduction of Alkynes to cis-Alkenes: Catalytic Hydrogenation
Like alkenes, alkynes can be reduced to alkanes in the presence of transition metal catalysts such as Pt, Pd, or Ni. The reaction involves two sequential syn additions of hydrogen via a cis-alkene intermediate.
Reduction of Alkenes: Catalytic Hydrogenation
Metals like palladium, platinum, and nickel are commonly used in their solid forms — fine powder on an inert surface. As these catalysts remain insoluble in the reaction mixture, they are referred to as heterogeneous catalysts.
The hydrogenation process takes place on the surface of...
Optimizing Chromatographic Separations
Band broadening refers to spreading solute bands as they travel through the column. This broadening can impact resolution. Plate height (H) represents the length required for one theoretical plate. A lower plate height corresponds to...

