scholarly journals MnOx-CeOx Nanoparticles Supported on Graphene Aerogel for Selective Catalytic Reduction of Nitric Oxides

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Zhuo Yao ◽  
Yuxiang Guo ◽  
Yujing Yang ◽  
Hong Huang ◽  
Dianli Qu
Keyword(s):  
Electron Microscopy ◽  
Selective Catalytic Reduction ◽  
Conversion Rate ◽  
High Efficiency ◽  
Catalytic Reduction ◽  
Hybrid Nanoparticles ◽  
Nitric Oxides ◽  
Graphene Aerogel ◽  
Catalytic Activities ◽  
Hierarchical Porous

Removal of nitric oxides (NOx) from stationary and transportation sources has been desired for environmental benefits. Selective catalytic reduction (SCR) of NOx by NH3 is attractive for its cost effectiveness and high efficiency but still technically challenging in consideration of operable temperatures. In this research, MnOx-CeOx hybrid nanoparticles supported on graphene aerogel (MnOx-CeOx/GA) are fabricated as the monolithic catalysts for potential applications to low-temperature SCR. The impacts of the particle size along with the amount and valency of catalytic elements in the nanocomposite on the catalytic activities are studied with the help of scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The catalyst crystallites are a few tens of nanometers and uniformly disperse on the surface of three-dimensional (3D) directionally aligned hierarchical porous graphene aerogel (GA) networks. The novel nanocomposite catalysts exhibit over 90% NOx conversion rate in a broad temperature range (200–300°C). Addition of CeOx into the MnOx-GA catalysts significantly reduces the operational temperature at the same conversion rate. In addition to Mn4+ ions in the catalysts, the adsorbed oxygen species which can be increased by the presence of low-valence cerium contribute to high catalytic activities in the MnOx-CeOx/GA catalysts.

Cu-Supported on Sodium-Treated Sepiolite for Selective Catalytic Reduction of NO by Propylene

2015 ◽  
Vol 1088 ◽  
pp. 569-572
Author(s):  
Zhi Hao Zhang ◽  
Yang Li ◽  
Yun Fang Qi ◽  
Qing Ye ◽  
Shu Lan Ji ◽  
...  
Keyword(s):  
Selective Catalytic Reduction ◽  
High Performance ◽  
Catalytic Reduction ◽  
Incipient Wetness Impregnation ◽  
Impregnation Method ◽  
Redox Species ◽  
Reduction Of No ◽  
Catalytic Activities ◽  
Scr Of No ◽  
Activity Center

Cu/Na-Sep samples were prepared by the incipient wetness impregnation method. These catalysts were characterized by means of XRF, XRD, and XPS techniques, and their catalytic activities were performed by the SCR of NO with propylene. The results show that the Cu/Na-Sep catalyst exhibited the high performance in the C3H6-SCR of NO. After investigation by XRD and XPS, the result showed that there are Cu2+/Cu+redox species as a reaction activity center over Cu/Na-Sep.

Selective Catalytic Reduction Impact on Heat Recovery Steam Generator Design and Operation

1986 ◽  
Author(s):  
James S. Davis ◽  
G. C. Duponteil
Keyword(s):  
Selective Catalytic Reduction ◽  
Gas Turbine ◽  
Steam Generator ◽  
Heat Recovery ◽  
Gas Flow ◽  
High Efficiency ◽  
Catalytic Reduction ◽  
Nox Reduction ◽  
Heat Recovery Steam Generator ◽  
The Impact

Selective Catalytic Reduction (SCR) is a post-combustion method to reduce the oxides of nitrogen (NOx), present in flue gases such as gas turbine exhaust streams, to N2 and water. It involves the injection of ammonia and the use of a catalyst module to promote the reaction to obtain high efficiency (60–86+%) NOx reduction. Several operating parameters can influence catalyst performance to include temperature, gas flow distribution, presence of sulfur compounds and catalyst age. This paper examines the impact of a SCR integration in a gas turbine heat recovery steam generator (HRSG) design/operation. Limitations on HRSG load and following capabilities, effect on capital cost and overall performance and current SCR system experience represent a number of areas that are examined.

scholarly journals Synthesis, Characterization and Catalytic Activities of MnOx/TiO2 in NO Selective Catalytic Reduction with NH3

2013 ◽  
Vol 25 (8) ◽  
pp. 4416-4418
Author(s):  
Junlin Xie ◽  
Zhengbing Fu ◽  
Feng He ◽  
Junfu Chen ◽  
De Fang ◽  
...  
Keyword(s):  
Selective Catalytic Reduction ◽  
Catalytic Reduction ◽  
Catalytic Activities

Selective Catalytic Reduction (SCR) System Installation and Commissioning at the Chow II Power Plant in Chowchilla, California

2003 ◽  
Author(s):  
Don Newburry ◽  
Pat Runnels ◽  
Mike Owings
Keyword(s):  
Power Plant ◽  
Natural Gas ◽  
Selective Catalytic Reduction ◽  
High Efficiency ◽  
Catalytic Reduction ◽  
Industrial Applications ◽  
Urea Solution ◽  
Lean Burn ◽  
High Oxygen Content ◽  
Scr System

Lean burn, natural gas, reciprocating engines are becoming widely utilized for stationary industrial applications due to their high efficiency and low emissions. However, despite the low engine emissions, some locations still require exhaust after-treatment to meet the local emissions requirements. Due to the high oxygen content (greater than 4%) in the exhaust of lean burn engines, 3-Way (non-selective) catalysts are not suitable to reduce NOx. Selective catalytic reduction (SCR), which utilizes a consumable reductant to reduce NOx over a catalyst, is very effective at reducing NOx and is becoming an accepted technology for large, stationary engine applications. In the summer of 2001, Stewart & Stevenson installed 16 Deutz TGB632V16 natural gas fired engines for NEO Corporation at the Chow II power plant. MIRATECH SCR provided and commissioned 16 selective catalytic reduction systems for these engines using a 40% urea solution as the reductant. This paper describes the installed SCR systems and reports some of the emissions testing results and costs. With the SCR systems in place, the engines were successfully able to meet the permitted exhaust emissions requirements of 0.07 g/bhp-hr of NOx, 0.1 g/bhp-hr of CO, and 0.15 g/bhp-hr of VOC’s (volatile organic compounds) with less than 10 ppmvd of ammonia slip @ 15% O2. Additional measurements were made of formaldehyde and acrolein. Very low levels of these emissions were found after the SCR.

scholarly journals Plasma-Assisted Selective Catalytic Reduction for Low-Temperature Removal of NOx and Soot Simulant

Catalysts ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 853 ◽  
Author(s):  
Van Toan Nguyen ◽  
Duc Ba Nguyen ◽  
Iljeong Heo ◽  
Young Sun Mok
Keyword(s):  
Low Temperature ◽  
Selective Catalytic Reduction ◽  
High Efficiency ◽  
Catalytic Reduction ◽  
Hydrocarbon Fuel ◽  
Nox Removal ◽  
Barrier Discharge Plasma ◽  
Specific Input Energy ◽  
Operating Temperatures ◽  
Α Al2o3

The challenge that needs to be overcome regarding the removal of nitrogen oxides (NOx) and soot from exhaust gases is the low activity of the selective catalytic reduction of NOx at temperatures fluctuating from 150 to 350 °C. The primary goal of this work was to enhance the conversion of NOx and soot simulant by employing a Ag/α-Al2O3 catalyst coupled with dielectric barrier discharge plasma. The results demonstrated that the use of a plasma-catalyst process at low operating temperatures increased the removal of both NOx and naphthalene (soot simulant). Moreover, the soot simulant functioned as a reducing agent for NOx removal, but with low NOx conversion. The high efficiency of NOx removal required the addition of hydrocarbon fuel. In summary, the combined use of the catalyst and plasma (specific input energy, SIE ≥ 60 J/L) solved the poor removal of NOx and soot at low operating temperatures or during temperature fluctuations in the range of 150–350 °C. Specifically, highly efficient naphthalene removal was achieved with low-temperature adsorption on the catalyst followed by the complete decomposition by the plasma-catalyst at 350 °C and SIE of 90 J/L.

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