Study of Improvements in NOx Reduction Performance on Simultaneous Reduction System of PM and NOx

2005 ◽  
Author(s):  
Shigeru Itabashi ◽  
Kuniaki Niimi ◽  
Shinji Kamoshita ◽  
Akira Shoji ◽  
Tomihisa Oda ◽  
...  
Keyword(s):  
Nox Reduction ◽  
Simultaneous Reduction ◽  
Reduction System

A New SOx Deactivation-Free NOx Reduction System Using Rh/Alumina and periodical Rich and Lean Conditions

1998 ◽  
Vol 27 (10) ◽  
pp. 1029-1030
Author(s):  
Tadao Nakatsuji ◽  
Ritsu Yasukawa ◽  
Keiichi Tabata ◽  
Kazuyuki Ueda ◽  
Miki Niwa
Keyword(s):  
Nox Reduction ◽  
Reduction System ◽  
Lean Conditions

scholarly journals SCR NOx Reduction System and Machinery Outfitting

2013 ◽  
Vol 48 (1) ◽  
pp. 21-23
Author(s):  
Teruhisa Koga ◽  
Takaaki Kubo ◽  
Satoru Fukuya ◽  
Ryoma Aosaka
Keyword(s):  
Nox Reduction ◽  
Reduction System

Development of a Simultaneous Reduction System of NOx and Particulate Matter for Light-Duty Truck

2004 ◽  
Author(s):  
Akira Shoji ◽  
Shinji Kamoshita ◽  
Tetsu Watanabe ◽  
Toshiaki Tanaka ◽  
Masahiko Yabe
Keyword(s):  
Particulate Matter ◽  
Simultaneous Reduction ◽  
Light Duty ◽  
Reduction System ◽  
Light Duty Truck

scholarly journals Quantification of the enhanced effectiveness of NO<sub><i>x</i></sub> control from simultaneous reductions of VOC and NH<sub>3</sub> for reducing air pollution in the Beijing–Tianjin–Hebei region, China

2018 ◽  
Vol 18 (11) ◽  
pp. 7799-7814 ◽  
Author(s):  
Jia Xing ◽  
Dian Ding ◽  
Shuxiao Wang ◽  
Bin Zhao ◽  
Carey Jang ◽  
...  
Keyword(s):  
Urban Areas ◽  
Transport Model ◽  
Nox Reduction ◽  
Reduction Rate ◽  
Chemical Transport Model ◽  
Simultaneous Reduction ◽  
Normalized Error ◽  
Emission Changes ◽  
Nox Control ◽  
Rsm Model

Abstract. As one common precursor for both PM2.5 and O3 pollution, NOx gains great attention because its controls can be beneficial for reducing both PM2.5 and O3. However, the effectiveness of NOx controls for reducing PM2.5 and O3 are largely influenced by the ambient levels of NH3 and VOC, exhibiting strong nonlinearities characterized as NH3-limited/NH3-poor and NOx-/VOC-limited conditions, respectively. Quantification of such nonlinearities is a prerequisite for making suitable policy decisions but limitations of existing methods were recognized. In this study, a new method was developed by fitting multiple simulations of a chemical transport model (i.e., Community Multiscale Air Quality Modeling System, CMAQ) with a set of polynomial functions (denoted as “pf-RSM”) to quantify responses of ambient PM2.5 and O3 concentrations to changes in precursor emissions. The accuracy of the pf-RSM is carefully examined to meet the criteria of a mean normalized error within 2 % and a maximal normalized error within 10 % by using 40 training samples with marginal processing. An advantage of the pf-RSM method is that the nonlinearity in PM2.5 and O3 responses to precursor emission changes can be characterized by quantitative indicators, including (1) a peak ratio (denoted as PR) representing VOC-limited or NOx-limited conditions, (2) a suggested ratio of VOC reduction to NOx reduction to avoid increasing O3 under VOC-limited conditions, (3) a flex ratio (denoted as FR) representing NH3-poor or NH3-rich conditions, and (4) enhanced benefits in PM2.5 reductions from simultaneous reduction of NH3 with the same reduction rate of NOx. A case study in the Beijing–Tianjin–Hebei region suggested that most urban areas present strong VOC-limited conditions with a PR from 0.4 to 0.8 in July, implying that the NOx emission reduction rate needs to be greater than 20–60 % to pass the transition from VOC-limited to NOx-limited conditions. A simultaneous VOC control (the ratio of VOC reduction to NOx reduction is about 0.5–1.2) can avoid increasing O3 during the transition. For PM2.5, most urban areas present strong NH3-rich conditions with a PR from 0.75 to 0.95, implying that NH3 is sufficiently abundant to neutralize extra nitric acid produced by an additional 5–35 % of NOx emissions. Enhanced benefits in PM2.5 reductions from simultaneous reduction of NH3 were estimated to be 0.04–0.15 µg m−3 PM2.5 per 1 % reduction of NH3 along with NOx, with greater benefits in July when the NH3-rich conditions are not as strong as in January. Thus, the newly developed pf-RSM model has successfully quantified the enhanced effectiveness of NOx control, and simultaneous reduction of VOC and NH3 with NOx can assure the control effectiveness of PM2.5 and O3.

Development of NOx Reduction System for Diesel Aftertreatment with Sulfur Trap Catalyst

2007 ◽  
Author(s):  
Kohei Yoshida ◽  
Takamitsu Asanuma ◽  
Hiromasa Nishioka ◽  
Kotaro Hayashi ◽  
Shinya Hirota
Keyword(s):  
Nox Reduction ◽  
Reduction System
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