Perspective on SCR NOx control for diesel vehicles

The selective catalytic reduction of NOx with aqueous urea (“urea SCR”) is originally a steady-state technology that has been successfully applied to diesel vehicles worldwide. This Perspective summarizes 20+ years of SCR system research, design, and future improvements.

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Catalytic Performance and Steady-State Kinetics of Cu-ZSM-5 for Selective Catalytic Reduction of NO with NH3

Acta Physico-Chimica Sinica ◽

10.3866/pku.whxb201202232 ◽

2012 ◽

Vol 28 (05) ◽

pp. 1230-1236 ◽

Cited By ~ 1

Author(s):

ZHANG Qiu-Lin ◽

◽

XU Hai-Di ◽

QIU Chun-Tian ◽

LIN Tao ◽

...

Keyword(s):

Steady State ◽

Selective Catalytic Reduction ◽

Catalytic Reduction ◽

Catalytic Performance ◽

Reduction Of No ◽

Steady State Kinetics ◽

Kinetics Of

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Transient reaction analysis and steady-state kinetic study of selective catalytic reduction of NO and NO+NO2 by NH3 over Fe/ZSM-5

Applied Catalysis A General ◽

10.1016/j.apcata.2009.06.036 ◽

2009 ◽

Vol 366 (1) ◽

pp. 84-92 ◽

Cited By ~ 37

Author(s):

Masaoki Iwasaki ◽

Kiyoshi Yamazaki ◽

Hirofumi Shinjoh

Keyword(s):

Steady State ◽

Kinetic Study ◽

Selective Catalytic Reduction ◽

Catalytic Reduction ◽

Reduction Of No ◽

Steady State Kinetic ◽

State Kinetic

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A Computational Investigation of Industrial Selective Catalytic Reduction Systems for NOx Control

Journal of Energy Resources Technology ◽

10.1115/1.4039606 ◽

2018 ◽

Vol 140 (8) ◽

Cited By ~ 1

Author(s):

Oghare Victor Ogidiama ◽

Tariq Shamim

Keyword(s):

Selective Catalytic Reduction ◽

Catalytic Reduction ◽

Inlet Temperature ◽

Complex Processes ◽

Fast Scr ◽

Conversion Performance ◽

Nox Control ◽

No2 Reduction ◽

Scr System ◽

Reaction Processes

The selective catalytic reduction (SCR) is a promising NOx (a mixture of NO and NO2) reduction technology for various applications. The SCR process entails the conversion of NOx by the use of a reducing agent such as ammonia and a suitable catalyst. Due to increasingly stricter NOx emission regulations, the SCR technology for NOx control needs continuous improvement. The improvement requires better understanding of complex processes occurring in the SCR system. The current study employs a mathematical model to elucidate the effect of key operating and geometric parameters on the performance of SCR systems. The model considers both standard and fast SCR reaction processes. The model was used to investigate the effects of NH3/NOx and NO2/NOx ratios in the exhaust on the SCR performance and the effect of using a dual layer SCR system. Furthermore, the effect of different operating parameters and the interdependence of parameters is analyzed by using a factorial approach. The results show that the SCR performance is very sensitive to NH3/NOx ratio. The SCR performance is also affected by the NO2/NOx ratio particularly at low temperatures. The optimal NOx conversion performance requires a combination of NH3/NOx ratio of 1.0, NO2/NOx ratio of 0.5, low space velocities, and high inlet temperature. The results depict that adding a second catalyzed layer results in increased reaction activity especially when the concentration is still high after the first layer.

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