Modeling of Non-Road Diesel Exhaust Aftertreatment Systems: Diesel Oxidation and Selective Catalytic Reduction Catalysts

2010 ◽  
Author(s):  
Maya R. Desai ◽  
Monica Tutuianu ◽  
Mehrdad Ahmadinejad ◽  
Timothy C. Watling ◽  
Andrew P.E. York ◽  
...  
Keyword(s):  
Selective Catalytic Reduction ◽  
Diesel Exhaust ◽  
Catalytic Reduction ◽  
Exhaust Aftertreatment ◽  
Diesel Oxidation ◽  
Aftertreatment Systems ◽  
Reduction Catalysts

It is no laughing matter: nitrous oxide formation in diesel engines and advances in its abatement over rhodium-based catalysts

2016 ◽  
Vol 6 (21) ◽  
pp. 7671-7687 ◽  
Author(s):  
Magdalena Jabłońska ◽  
Regina Palkovits
Keyword(s):  
Nitrous Oxide ◽  
Diesel Engine ◽  
Selective Catalytic Reduction ◽  
Catalytic Reduction ◽  
Oxide Formation ◽  
Diesel Oxidation Catalysts ◽  
Diesel Oxidation ◽  
Ammonia Slip ◽  
Aftertreatment Systems ◽  
By Products

N2O appears as one of the undesired by-products in exhaust gases emitted from diesel engine aftertreatment systems, such as diesel oxidation catalysts (DOC), lean NOx trap (LNT, also known as NOx storage and reduction (NSR)) or selective catalytic reduction (NH3-SCR and HC-SCR) and ammonia slip catalysts (ASC, AMOX, guard catalyst).

scholarly journals Accelerated performance and durability test of the exhaust aftertreatment system by contaminated biodiesel

2017 ◽  
Vol 18 (10) ◽  
pp. 1067-1076 ◽  
Author(s):  
Jörg Schröder ◽  
Franziska Hartmann ◽  
Robert Eschrich ◽  
Denis Worch ◽  
Jürgen Böhm ◽  
...  
Keyword(s):  
Selective Catalytic Reduction ◽  
Alternative Fuels ◽  
Test Bench ◽  
Catalytic Reduction ◽  
Diesel Oxidation Catalyst ◽  
Oxidation Catalyst ◽  
Exhaust Aftertreatment ◽  
Aftertreatment System ◽  
Exhaust Aftertreatment System ◽  
Diesel Oxidation

The consumption of fossil and especially alternative fuels from renewable sources is supposed to rise in the future. Biofuels as well as fossil fuels often contain alkali and alkaline earth metal impurities that are potential poisons for automotive exhaust catalysts. The impact of these contaminations on the long-time performance of the exhaust aftertreatment system is a major concern. However, engine test bench studies consume considerable amounts of fuel, manpower and time. The purpose of this research project was to examine whether accelerated engine tests can be achieved by a modified diesel aftertreatment system in a test bench and contamination of biodiesel with known amounts of elements potentially poisoning automotive catalysts. A variety of potentially harmful elements (sodium (Na), potassium (K), calcium (Ca), magnesium (Mg), sulfur (S) and phosphorous (P)) were added all at once to enhance the contamination level in biodiesel. A diesel oxidation catalyst and a catalyst for selective catalytic reduction reaction were placed in a stream of exhaust gas generated with a single cylinder engine. For reference purposes, a second test series was performed with a commercially available biodiesel. Catalysts were analyzed post-mortem using a bench flow reactor and X-ray fluorescence regarding their activity and deposition of the harmful elements. For both diesel oxidation catalyst and selective catalytic reduction catalysts, significant deactivation and decrease in conversion rates could be proven. For diesel oxidation catalyst, linear correlations between mass fractions of added elements and aging time were observed.

Comparative analysis on the effects of diesel particulate filter and selective catalytic reduction systems on a wide spectrum of chemical species emissions

2018 ◽  
Author(s):  
Z. Gerald Liu ◽  
Devin R. Berg ◽  
Thaddeus A. Swor ◽  
James J. Schauer‡
Keyword(s):  
Diesel Engine ◽  
Selective Catalytic Reduction ◽  
Diesel Particulate Filter ◽  
Catalytic Reduction ◽  
Wide Spectrum ◽  
Chemical Species ◽  
Pollutant Emissions ◽  
Particulate Filter ◽  
Diesel Particulate ◽  
Aftertreatment Systems

Two methods, diesel particulate filter (DPF) and selective catalytic reduction (SCR) systems, for controlling diesel emissions have become widely used, either independently or together, for meeting increasingly stringent emissions regulations world-wide. Each of these systems is designed for the reduction of primary pollutant emissions including particulate matter (PM) for the DPF and nitrogen oxides (NOx) for the SCR. However, there have been growing concerns regarding the secondary reactions that these aftertreatment systems may promote involving unregulated species emissions. This study was performed to gain an understanding of the effects that these aftertreatment systems may have on the emission levels of a wide spectrum of chemical species found in diesel engine exhaust. Samples were extracted using a source dilution sampling system designed to collect exhaust samples representative of real-world emissions. Testing was conducted on a heavy-duty diesel engine with no aftertreatment devices to establish a baseline measurement and also on the same engine equipped first with a DPF system and then a SCR system. Each of the samples was analyzed for a wide variety of chemical species, including elemental and organic carbon, metals, ions, n-alkanes, aldehydes, and polycyclic aromatic hydrocarbons, in addition to the primary pollutants, due to the potential risks they pose to the environment and public health. The results show that the DPF and SCR systems were capable of substantially reducing PM and NOx emissions, respectively. Further, each of the systems significantly reduced the emission levels of the unregulated chemical species, while the notable formation of new chemical species was not observed. It is expected that a combination of the two systems in some future engine applications would reduce both primary and secondary emissions significantly.

Recent progress of metal-exchanged zeolites for selective catalytic reduction of NOx with NH3 in diesel exhaust

Fuel ◽  
2021 ◽  
Vol 305 ◽  
pp. 121482
Author(s):  
Xiaofeng Wang ◽  
Yang Xu ◽  
Zhe Zhao ◽  
Jianbin Liao ◽  
Chen Chen ◽  
...  
Keyword(s):  
Selective Catalytic Reduction ◽  
Diesel Exhaust ◽  
Recent Progress ◽  
Catalytic Reduction ◽  
Reduction Of Nox

Experimental and kinetic analysis of hydrothermal aging effects on ammonia adsorption capacity over a commercial Cu-zeolite selective catalytic reduction catalyst

2018 ◽  
Vol 233 (12) ◽  
pp. 3030-3042
Author(s):  
Tae Joong Wang ◽  
In Hyuk Im
Keyword(s):  
Adsorption Capacity ◽  
Selective Catalytic Reduction ◽  
Catalytic Reduction ◽  
Adsorption Site ◽  
Selective Catalytic Reduction Catalyst ◽  
Aging Effects ◽  
Hydrothermal Aging ◽  
Ammonia Adsorption ◽  
Fresh Catalyst ◽  
Reduction Catalysts

Ammonia/urea selective catalytic reduction is an efficient technology to control NOx emission from diesel engines. One of its critical challenges is the performance degradation of selective catalytic reduction catalysts due to the hydrothermal aging experienced in real-world operations during the lifetime. In this study, hydrothermal aging effects on the reduction of ammonia adsorption capacity over a commercial Cu-zeolite selective catalytic reduction catalyst were investigated under actual engine exhaust conditions. Ammonia adsorption site densities of the selective catalytic reduction catalysts aged at two different temperatures of 750°C and 850°C for 25 h with 10% H2O were experimentally measured and compared to that of fresh catalyst on a dynamometer test bench with a heavy-duty diesel engine. The test results revealed that hydrothermal aging significantly decreased the ammonia adsorption capacity of the current commercial Cu-zeolite selective catalytic reduction catalyst. Hydrothermal treatment at 750°C reduced the ammonia adsorption site to 62.5% level of that of fresh catalyst, while hydrothermal treatment at 850°C lowered the adsorption site to 37.0% level of that of fresh catalyst. Also, in this study, numerical simulation and kinetic analysis were carried out to quantify the impact of hydrothermal aging on the reduction of ammonia adsorption capacity by introducing an aging coefficient. The kinetic parameter calibrations based on actual diesel engine tests with a commercial monolith Cu-zeolite selective catalytic reduction catalyst provided a highly realistic kinetic parameter set of ammonia adsorption/desorption and enabled a mathematical description of hydrothermal aging effect.

Hydrocarbon catalyzed-selective catalytic reduction catalysts using core-shell atomic layer deposited CeO2 and ZrO2

2019 ◽  
Vol 37 (2) ◽  
pp. 020919 ◽  
Author(s):  
David H. K. Jackson ◽  
Michael M. Schwartz ◽  
Chilan Ngo ◽  
Dustin Facteau ◽  
Svitlana Pylypenko ◽  
...  
Keyword(s):  
Selective Catalytic Reduction ◽  
Catalytic Reduction ◽  
Atomic Layer ◽  
Core Shell ◽  
Reduction Catalysts
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