Chapter 1. Review of deNOx Technology for Mobile Applications

Johnson, Timothy V.; Joshi, A.

doi:10.1039/9781788013239-00001

Cited by 12 publications

(6 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In cycling NO x storage-reduction (NSR) catalysts to treat diesel tail gases, Pt particles deposited on an external coating of BaO work in both lean and rich conditions. In the first case, Pt catalyzes the full oxidation of nitrogen oxides to NO 2 while forming BaNO 3 ; in the second, it catalyzes the reaction between nitrates and excess fuel. − ,− With time, NO x oxidizes Pt, but thermally treating the system produces coarse particles, which minimizes the oxidation rate . Activity and thermal stability are higher for Pt-Pd and Pt-Rh bimetallic particles or three-way catalysts (TWCs) − ,, when successfully deposited by ionic exchange on γ-Al 2 O 3 or on a mixture of CeO 2 -ZrO 2 -γ-Al 2 O 3 on preoxidized FeCrAl fibers .…”

Section: Applications In Emission Controlmentioning

confidence: 99%

FeCrAl as a Catalyst Support

et al. 2020

View full text Add to dashboard Cite

The iron-chromium-aluminum alloy (FeCrAl) is an exceptional support for highly exothermic and endothermic reactions that operate above 700 °C in chemically aggressive environments, where low heat and mass transfer rates limit reaction yield. FeCrAl two-and three-dimensional structured networksmonoliths, foams, and fibersmaximize mass transfer rates, while their remarkable thermal conductivity minimizes hot spots and thermal gradients. Another advantage of the open FeCrAl structure is the low pressure drop due to the high void fraction and regularity of the internal path. The surface Al 2 O 3 layer, formed after an initial thermal oxidation, supports a wide range of metal and metal oxide active phases. The aluminum oxide that adheres to the metal surface protects it from corrosive atmospheres and carbon (carburization), thus allowing FeCrAl to operate at a higher temperature. The top applications are industrial burners, in which compact knitted metal fibers distribute heat over large surface areas, and automotive tail gas converters. Future applications include producing H 2 and syngas from remote natural gas in modular units. This Review summarizes the specific preparation techniques, details process operating conditions and catalyst performance of several classes of reactions, and highlights positive and challenging aspects of FeCrAl.

show abstract

Section: Applications In Emission Controlmentioning

confidence: 99%

FeCrAl as a Catalyst Support

et al. 2020

View full text Add to dashboard Cite

show abstract

“…Selective catalytic reduction with ammonia (NH 3 -SCR) is a technology used to abate nitrogen oxide emissions from diesel engines effectively [26]. Vanadium-based oxides, copper zeolite, and iron zeolite are three general families of SCR catalysts for commercial use today [27]. Copper zeolite has been the leading choice due to the high activity under a wide temperature window, among which small-pore zeolites such as CHA have shown especially good hydrothermal stability and excellent resistance to HC poisoning [28].…”

Section: Selective Catalytic Reduction (Scr)mentioning

confidence: 99%

Exhaust Gas After-Treatment Systems for Gasoline and Diesel Vehicles

Bao¹,

Wang²,

Shi³

et al. 2022

IJAMM

View full text Add to dashboard Cite

Review Exhaust Gas After-Treatment Systems for Gasoline and Diesel Vehicles Liye Bao 1, Jihua Wang 2, Lihui Shi 2, and Haijun Chen 1, * 1 College of Electronic Information and Optical Engineering, Nankai University, Tianjin 300350, China 2 Valiant Co., Ltd., Yantai 264006, China * Correspondence: chenhj@nankai.edu.cn Received: 5 October 2022 Accepted: 10 November 2022 Published: 25 December 2022 Abstract: Exhaust gases released from vehicle engines have been a major cause of air pollution, and the emission limits have become much stricter in recent years due to a worldwide concern about the impact of air pollution on public health. These regulations have been complied to minimize the emissions of carbon monoxide (CO), hydrocarbons (HCs), nitrogen oxides (NO x) and particulate matter (PM) from gasoline and diesel vehicles engines. Different after-treatment systems (ATS) have been developed for the treatment of exhaust gases from gasoline and diesel engines, respectively. The ATS for gasoline engine based on the three-way catalysts (TWCs), as well as the ATS for diesel engines including diesel oxidation catalysts (DOC), selective catalytic reduction (SCR), diesel particulate filters (DPF) and ammonia slip catalysts (ASC), are summarized in this mini-review.

show abstract

“…Among the most effective is Selective Catalytic Reduction (SCR), an exhaust after-treatment method; in SCR, NO x reacts catalytically with ammonia to form non-pollutants nitrogen and water [5]. SCR requires a certain exhaust gas temperature to decompose the urea solution to ammonia and also to convert the NO x ; typically, the urea decomposition reaction stops below exhaust temperatures of 180 • C. Injecting urea at temperatures below this can result in unwanted deposits, although there are techniques enabling conversion at temperatures as low as 150 • C on the most modern systems [6].…”

Section: Introductionmentioning

confidence: 99%

Identifying NOx Hotspots in Transient Urban Driving of Two Diesel Buses and a Diesel Car

2020

View full text Add to dashboard Cite

NO x emissions from vehicles have been a substantial cause for concern due to their impact on urban air quality. In particular, despite reducing levels of permitted emissions legislatively, such reductions have not been observed in the real world. In this work, NO x emissions from three vehicles-a Euro 5 car, a Euro V hybrid bus, and a Euro VI-bus have been measured in real driving conditions (and in the case of the buses-in full passenger service). A recently developed high spatio-temporal resolution technique combining very fast (10 ms) NO x measurement with differential GPS accurate to 1 cm allows these emissions to be resolved to a distance of less than 10 cm (worst-case-dependent on vehicle speed). The results show that acceleration events for the vehicles play a significant part in their total NO x emissions. In addition, standard events such as a speed bump and a bus stop are analysed. The temperature of any aftertreatment (catalytic converter) to reduce NO x emissions is also observed to be of substantial significance. At idle, the passenger car was observed to near-double its NO x emissions when the air conditioning was switched on. Finally, the real driving conditions are compared to the legislative compliance cycles for the certification of the buses, and those results used to further understand the observed NO x emissions.

show abstract

Chapter 1. Review of deNOx Technology for Mobile Applications

Cited by 12 publications

References 0 publications

FeCrAl as a Catalyst Support

FeCrAl as a Catalyst Support

Exhaust Gas After-Treatment Systems for Gasoline and Diesel Vehicles

Identifying NOx Hotspots in Transient Urban Driving of Two Diesel Buses and a Diesel Car

Contact Info

Product

Resources

About