SELECTIVE CATALYTIC REDUCTION (SCR) OF NO BY AMMONIA OVER V2O5/TiO2 CATALYST IN A CATALYTIC FILTER MEDIUM AND HONEYCOMB REACTOR: A KINETIC MODELING STUDY

Nahavandi, Milad

doi:10.1590/0104-6632.20150324s00003584

Cited by 19 publications

(10 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…S10), which would affect the injection of Adblue. Insufficient injection would result in low conversion efficiency of NO and NO2, while over injection would cause undesirable NH3 emissions to the atmosphere [30].…”

Section: Exhaust After-treatment System I) Doc Blockagementioning

confidence: 99%

Impact of potential engine malfunctions on fuel consumption and gaseous emissions of a Euro VI diesel truck

Huang

Yam³

et al. 2019

Energy Conversion and Management

View full text Add to dashboard Cite

Although new vehicles are designed to comply with specific emission regulations, their in-service performance would not necessarily achieve them due to wear-and-tear and improper maintenance of engine components as well as tampering or failure of the engine control and exhaust after-treatment systems. However, there is a lack of knowledge on how much these potential malfunctions affect vehicle performance. Therefore, this study was conducted to simulate the effect of some common engine malfunctions on the fuel consumption and gaseous emissions of a 16-tonne Euro VI diesel truck using transient chassis dynamometer testing. The simulated malfunctions included those that would commonly occur in the intake, fuel injection, exhaust after-treatment and other systems. The results showed that all malfunctions increased fuel consumption except for the malfunction of EGR fully closed which reduced fuel consumption by 31%. The biggest increases in fuel consumption were caused by malfunctions in the intake system (16%-43%), followed by the exhaust after-treatment (6%-30%), fuel injection (4%-24%) and other systems (6%-11%). Regarding pollutant emissions, the effect of engine malfunctions on HC and CO emissions was insignificant, which remained unchanged or even reduced for most cases. An exception was EGR fully open which increased HC and CO emissions by 3.4 and 11.2 times, respectively. Contrary to HC and CO emissions, NO emissions were significantly increased by malfunctions. The largest increases in NO emissions were caused by malfunctions in the after-treatment system, ranging from 38% (SCR) to 16.1 times (DPF pressure sensor). Malfunctions in the fuel injection system (24%-12.6 times) and intercooler (4.4-6.0 times) could also increase NO emissions markedly. This study demonstrated clearly the significance of having properly functioning engine control and exhaust after-treatment systems to achieve the required performance of fuel consumption and pollutant emissions.

show abstract

Section: Exhaust After-treatment System I) Doc Blockagementioning

confidence: 99%

Impact of potential engine malfunctions on fuel consumption and gaseous emissions of a Euro VI diesel truck

Huang

Yam³

et al. 2019

Energy Conversion and Management

View full text Add to dashboard Cite

show abstract

“…In the mathematical model of proposed mechanism, all reaction kinetics were assumed to be in first order, as shown below in eqs 4–8, where the reaction rate constants are governed by Arrhenius equation based on eq . , The reversible mass transfer equations for HMF extraction as well as its respective equilibrium coefficient are also presented in eqs 10–12. …”

Section: Resultsmentioning

confidence: 99%

Efficient Conversion of Glucose into 5-Hydroxymethylfurfural Using a Sulfonated Carbon-Based Solid Acid Catalyst: An Experimental and Numerical Study

Nahavandi

Rao

Yuan

et al. 2019

ACS Sustainable Chem. Eng.

View full text Add to dashboard Cite

In this study, a sulfonated oxidized activated carbon (SO 3 H-OAC) catalyst was prepared through oxidation of activated carbon (OAC) followed by sulfonation and characterized by different characterization techniques such as FTIR, Pyridine-FTIR, XRD, TPD-NH 3 /CO 2 , BET, TGA, Raman, and elemental analysis. The as-synthesized SO 3 H-OAC catalyst bearing sulfonyl hydroxide (−SO 3 H), hydroxyl (−OH), and carboxyl (−COOH) functional groups with strong Brønsted base and acid sites could demonstrate an excellent bifunctional activity in conversion of glucose into 5-hydroxymethylfurfural (HMF) in a biphasic THF/H 2 O-NaCl solvent system (3:1 v/v), achieving almost 93% HMF yield and selectivity at 160 °C in 3 h. The catalyst could also show a remarkable recyclability and was used for 5 recycles without substantial loss in catalytic activity. A comprehensive mathematical model was also developed to evaluate the consecutive conversion of glucose, and respective kinetic parameters were identified by an inverse modeling technique using COMSOL Multiphysics software. Based on numerical modeling, activation energies of 54.6 and 26.6 kJ/mol were respectively achieved for glucose isomerization to fructose and consecutive fructose dehydration to HMF, signifying that fructose could convert into HMF more readily than glucose.

show abstract

“…In the catalyst, the exhausted NO x in combination with ammonia is decomposed into H 2 O and N 2 . 7 Therefore, the chemical processes that urea undergoes to transform into the NO x reducing agent needs to be properly understood. An inappropriate mixing with the surrounding air and incomplete evaporation before entering the catalyst could lead into low SCR efficiencies.…”

Section: Introductionmentioning

confidence: 99%

“…In the catalyst, the exhausted NO x in combination with ammonia is decomposed into H 2 O and N 2 . Therefore, the chemical processes that urea undergoes to transform into the NO x reducing agent needs to be properly understood.…”

Section: Introductionmentioning

confidence: 99%

Numerical Analysis of Urea to Ammonia Conversion in Automotive Selective Catalytic Reduction Realistic Conditions

Payri

Martí-Aldaraví

Marco-Gimeno

2021

Ind. Eng. Chem. Res.

View full text Add to dashboard Cite

The selective catalytic reduction (SCR) is a technology employed for NO x reduction purposes which is based on the injection of an Urea Water Solution (UWS) into the exhaust line. Conversion of this injected urea into ammonia is a key step to ensure high SCR efficiency. In order to study this phenomenon, a three-dimensional model of the urea–water injection process has been created to recreate realistic conditions. A Lagrangian–Eulerian approach has been followed to model liquid and gas phases, respectively. Droplet evaporation as well as relevant chemical processes have been included to recreate the thermolysis and hydrolysis phenomena, and the results have been validated against literature data. Then, the validated model has been applied to recreate an in-house experimental facility that measured spray macroscopic and microscopic characteristics by means of diffused back illumination (DBI) visualization. Probability density functions of the UWS droplet sizes as well as the velocity distributions have been obtained at three different regions of interest to be compared with the experimental data set. Contours of isocyanic acid and ammonia mass fractions have been included to show the chemical transformation from urea into its products. The model accurately replicates the experimental results, and it stands as a good methodology to predict the main spray characteristics as well as the chemical processes that take place in actual SCR systems.

show abstract

SELECTIVE CATALYTIC REDUCTION (SCR) OF NO BY AMMONIA OVER V2O5/TiO2 CATALYST IN A CATALYTIC FILTER MEDIUM AND HONEYCOMB REACTOR: A KINETIC MODELING STUDY

Cited by 19 publications

References 16 publications

Impact of potential engine malfunctions on fuel consumption and gaseous emissions of a Euro VI diesel truck

Impact of potential engine malfunctions on fuel consumption and gaseous emissions of a Euro VI diesel truck

Efficient Conversion of Glucose into 5-Hydroxymethylfurfural Using a Sulfonated Carbon-Based Solid Acid Catalyst: An Experimental and Numerical Study

Numerical Analysis of Urea to Ammonia Conversion in Automotive Selective Catalytic Reduction Realistic Conditions

Contact Info

Product

Resources

About