Improvement of NOX Reduction Rate of Urea SCR System Applied for an Non-Road Diesel Engine

Han, Joonsoo; Jung, Haksup; Pyo, Sukang; Cho, Gyubaek; Oh, Young-Taig; Kim, Hongsuk

doi:10.1007/s12239-019-0108-6

Cited by 14 publications

(10 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The trucks and large buses with GVWs of 40 tons or higher, which were often driven under high-speed conditions, showed no significant differences compared to the 7-15-ton trucks. SCR systems applied to Euro 6 HDV can maintain low levels of NOx emissions regardless of GVW due to the improved low temperature performance of SCR catalysts and the insulation of exhaust lines [31,32]. The current vehicle emission factors were calculated as a function of the average vehicle speed by driving in various modes separately from the certification test mode in the chassis dynamometer.…”

Section: Euro 5 and Euro 6 Vehicle Emissionsmentioning

confidence: 99%

NOx Emissions from Euro 5 and Euro 6 Heavy-Duty Diesel Vehicles under Real Driving Conditions

Park

Kang

et al. 2020

Energies

View full text Add to dashboard Cite

Despite the strengthening of vehicle emissions standards and test methods, nitrogen oxide (NOx) emissions from on-road mobile sources are not being notably reduced. The introduction of real driving emission (RDE) regulations is expected to reduce the discrepancy between emission regulations and actual air pollution. To analyze the effects of RDE regulations on heavy-duty diesel vehicles, pollutants emitted while driving were measured using a portable emission measurement system (PEMS) for Euro 5 and Euro 6 vehicles, which were produced before and after RDE regulations, respectively. NOx emissions were compared as a function of emissions allowance standards, gross vehicle weight (GVW), average vehicle speed, and ambient temperature. NOx emissions from Euro 6 vehicles were found to be low, regardless of GVW; emissions from both vehicular categories increased with a decline in the average speed. To reflect real road driving characteristics more broadly in the RDE test method for heavy-duty vehicles, it is necessary to consider engine power, which is a criterion for classifying effective sections, in the moving average window (MAW) analysis method, as well as including cold start conditions.

show abstract

Section: Euro 5 and Euro 6 Vehicle Emissionsmentioning

confidence: 99%

NOx Emissions from Euro 5 and Euro 6 Heavy-Duty Diesel Vehicles under Real Driving Conditions

Park

Kang

et al. 2020

Energies

View full text Add to dashboard Cite

show abstract

“…It is therefore critical to minimize N 2 O formation in after-treatment systems during reduction of nitrogen oxides (NOx). Achieving higher NOx conversion results in increased N 2 O emissions over conventional after-treatment systems such as selective catalytic reduction (SCR) and SCR combined with an ammonia slip catalyst (ASC) . Furthermore, N 2 O may also be formed over the diesel oxidation catalyst (DOC) commonly used in the after-treatment system .…”

Section: Introductionmentioning

confidence: 99%

“…Urea-SCR systems selectively convert engine-out NOx emissions to nitrogen (N 2 ) and water by using NH 3 resulting from thermal decomposition and hydrolysis of a urea solution. However, N 2 O is produced as one of the by-products during the SCR reactions of NOx over a wide temperature range. ,− Thermal decomposition of ammonium nitrate (AN) has been reported to be the main source of N 2 O formation at low temperature. − In the high-temperature region, both unselective ammonia oxidation and SCR reactions can result in N 2 O formation. ,, The development of robust novel catalyst materials having excellent DeNOx performance and lower N 2 O formation is therefore necessary.…”

Section: Introductionmentioning

confidence: 99%

N₂O Formation during NH₃-SCR over Different Zeolite Frameworks: Effect of Framework Structure, Copper Species, and Water

Han

Wang

Isapour

et al. 2021

Ind. Eng. Chem. Res.

Self Cite

View full text Add to dashboard Cite

The formation characteristics of N 2 O were investigated with respect to copper-functionalized zeolites, i.e., Cu/SSZ-13 (CHA), Cu/ZSM-5 (MFI), and Cu/BEA (BEA) and compared with the corresponding zeolites in the H form as references to elucidate the effect of the framework structure, copper addition, and water. Temperature-programmed reduction with hydrogen showed that the CHA framework has a higher concentration of Cu 2+ (Z2Cu) compared to MFI and BEA. The characterizations and catalyst activity results highlight that CHA has a framework structure that favors high formation of ammonium nitrate (AN) in comparison with MFI and BEA. Moreover, AN formation and decomposition were found to be promoted in the presence of Cu species. On the contrary, lower N 2 O formation was observed from Cu/CHA during standard and fast SCR reactions, which is proposed to be due to highly stabilized AN inside the zeolite cages. On the other hand, significant amounts of N 2 O were released during heating due to decomposition of AN, implying pros and cons of AN stability for Cu/CHA with possible uncontrolled N 2 O formation during transient conditions. Additionally, important effects of water were found, where water hinders AN formation and increases the selectivity for decomposition to NO 2 instead of N 2 O. Thus, less available AN forming N 2 O was observed in the presence of water. This was also observed in fast SCR conditions where all Cu/zeolites exhibited lower continuous N 2 O formation in the presence of water.

show abstract

“…Higher mass flow rates through the SCR had little effect on NO x reduction. This led to the inference that the residence time and space velocity was not affecting the NO x conversions at higher temperatures (300°C and 400°C), which was also noted by Han et al [17]. The same was reflected in the PN change across the SCR, i.e., residence time and space velocity had little or no influence in PN change across the SCR, at exhaust temperatures of 300°C and 400°C.…”

Section: Discussionmentioning

confidence: 61%

On the Effects of Urea and Water Injection on Particles across the SCR Catalyst in a Heavy - Duty Euro VI Diesel Engine

Prasath¹,

Bernemyr²,

Erlandsson³

2020

SAE Technical Paper Series

View full text Add to dashboard Cite

Particle emissions from heavy-duty engines are regulated both by mass and number by Euro VI regulation. Understanding the evolution of particle size and number from the exhaust valve to the tail pipe is of vital importance to expand the possibilities of particle reduction. In this study, experiments were carried out on a heavy-duty Euro VI engine after-treatment system consisting of diesel oxidation catalyst, diesel particulate filter and selective catalytic reduction (SCR) unit with AdBlue injection followed by ammonia slip catalyst. The present work focusses on the SCR unit with regard to total particle number with and without nucleation particles both. Experiments were conducted by varying the AdBlue injection quantity, SCR inlet temperature [to vary the reaction temperature], exhaust mass flow rate [to vary the residence time in SCR], and fuel injection pressures [to vary inlet particle number and inlet NO x ]. Sampling for particle measurements was performed at the inlet, upstream of the urea injector and the outlet of the SCR. Particle measurements were made using two different twostage dilution systems, for measuring non-volatile and volatile particles, respectively. The total particle number (PN) was measured using two different condensation particle counters (CPC), one with the cut-off size at 23nm and another with a cut-off size at 7 nm to capture nuclei mode particles. An increase in the total number of particles was observed at 400°C and 1200 bar of fuel injection pressure with the higher AdBlue injection quantities compared to the dry-run SCR. At 400°C, a surge in nucleation occurs irrespective of the fuel injection pressures. An experiment was also made to isolate the water droplets effect on PN from nitrate formation. The SCR was injected with de-ionized water and a PN reduction was observed across the SCR and the reduction was higher with higher inlet PN to the SCR.

show abstract

Improvement of NOX Reduction Rate of Urea SCR System Applied for an Non-Road Diesel Engine

Cited by 14 publications

References 22 publications

NOx Emissions from Euro 5 and Euro 6 Heavy-Duty Diesel Vehicles under Real Driving Conditions

NOx Emissions from Euro 5 and Euro 6 Heavy-Duty Diesel Vehicles under Real Driving Conditions

N₂O Formation during NH₃-SCR over Different Zeolite Frameworks: Effect of Framework Structure, Copper Species, and Water

On the Effects of Urea and Water Injection on Particles across the SCR Catalyst in a Heavy - Duty Euro VI Diesel Engine

Contact Info

Product

Resources

About

Improvement of NOX Reduction Rate of Urea SCR System Applied for an Non-Road Diesel Engine

Cited by 14 publications

References 22 publications

NOx Emissions from Euro 5 and Euro 6 Heavy-Duty Diesel Vehicles under Real Driving Conditions

NOx Emissions from Euro 5 and Euro 6 Heavy-Duty Diesel Vehicles under Real Driving Conditions

N2O Formation during NH3-SCR over Different Zeolite Frameworks: Effect of Framework Structure, Copper Species, and Water

On the Effects of Urea and Water Injection on Particles across the SCR Catalyst in a Heavy - Duty Euro VI Diesel Engine

Contact Info

Product

Resources

About

N₂O Formation during NH₃-SCR over Different Zeolite Frameworks: Effect of Framework Structure, Copper Species, and Water