Download or read book NOx Trap Catalysts and Technologies written by Luca Lietti and published by Royal Society of Chemistry. This book was released on 2018-06-13 with total page 434 pages. Available in PDF, EPUB and Kindle. Book excerpt: Vehicle exhaust emissions, particularly from diesel cars, are considered to be a significant problem for the environment and human health. Lean NOx Trap (LNT) or NOx Storage/Reduction (NSR) technology is one of the current techniques used in the abatement of NOx from lean exhausts. Researchers are constantly searching for new inexpensive catalysts with high efficiency at low temperatures and negligible fuel penalties, to meet the challenges of this field. This book will be the first to comprehensively present the current research on this important area. Covering the technology used, from its development in the early 1990s up to the current state-of-the-art technologies and new legislation. Beginning with the fundamental aspects of the process, the discussion will cover the real application standard through to the detailed modelling of full scale catalysts. Scientists, academic and industrial researchers, engineers working in the automotive sector and technicians working on emission control will find this book an invaluable resource.

Download or read book Lean NOx technology written by and published by . This book was released on 1996 with total page 33 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Study of Lean NOx Technology for Diesel Emission Control written by and published by . This book was released on 2000 with total page 17 pages. Available in PDF, EPUB and Kindle. Book excerpt: Diesel engines because of their reliability and efficiency are a popular mobile source. The diesel engine operates at higher compression ratios and with leaner fuel mixtures and produces lower carbon monoxide and hydrocarbon emissions. The oxygen-rich environment leads to higher nitrogen oxides in the form of NO. Catalysts selectively promoting the reduction of NOx by HCs in a lean environment have been termed lean NOx catalyst ''LNC''. The two groups that have shown most promise are, Copper exchanged zeolite Cu/ZSM5, and Platinum on alumina Pt/Al2O3.

Download or read book Lean NOx Trap Catalysis for Lean Burn Natural Gas Engines written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: As the nation's demand for energy grows along with concern for the environment, there is a pressing need for cleaner, more efficient forms of energy. The internal combustion engine is well established as one of the most reliable forms of power production. They are commercially available in power ranges from 0.5 kW to 6.5 MW, which make them suitable for a wide range of distributed power applications from small scale residential to large scale industrial. In addition, alternative fuels with domestic abundance, such as natural gas, can play a key role in weaning our nations dependence on foreign oil. Lean burn natural gas engines can achieve high efficiencies and can be conveniently placed anywhere natural gas supplies are available. However, the aftertreatment of Nox emissions presents a challenge in lean exhaust conditions. Unlike carbon monoxide and hydrocarbons, which can be catalytically reduced in lean exhaust, NOx emissions require a net reducing atmosphere for catalytic reduction. Unless this challenge of NOx reduction can be met, emissions regulations may restrict the implementation of highly efficient lean burn natural gas engines for stationary power applications. While the typical three-way catalyst is ineffective for NOx reduction under lean exhaust conditions, several emerging catalyst technologies have demonstrated potential. The three leading contenders for lean burn engine de-NOx are the Lean NOx Catalyst (LNC), Selective Catalytic Reduction (SCR) and the Lean Nox Trap (LNT). Similar to the principles of SCR, an LNT catalyst has the ability to store NOx under lean engine operation. Then, an intermittent rich condition is created causing the stored NOx to be released and subsequently reduced. However, unlike SCR, which uses urea injection to create the reducing atmosphere, the LNT can use the same fuel supplied to the engine as the reductant. LNT technology has demonstrated high reduction efficiencies in diesel applications where diesel fuel is the reducing agent. The premise of this research is to explore the application of Lean NOx Trap technology to a lean burn natural gas engine where natural gas is the reducing agent. Natural gas is primarily composed of methane, a highly stable hydrocarbon. The two primary challenges addressed by this research are the performance of the LNT in the temperature ranges experienced from lean natural gas combustion and the utilization of the highly stable methane as the reducing agent. The project used an 8.3 liter lean burn natural gas engine on a dynamometer to generate the lean exhaust conditions. The catalysts were packaged in a dual path aftertreatment system, and a set of valves were used to control the flow of exhaust to either leg during adsorption and regeneration.

Download or read book Diesel lean NOx Catalyst Technologies written by Society of Automotive Engineers and published by SAE International. This book was released on 1996 with total page 108 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Demonstration of Lean NOx Catalytic Converter Technology on a Heavy duty Diesel Engine written by Martin J. Heimrich and published by . This book was released on 1996 with total page 294 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book NOx Reduction with Natural Gas for Lean Large Bore Engine Applications Using Lean NOx Trap Aftertreatment written by JE. Parks and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Large-bore natural gas engines are used for distributed energy and gas compression since natural gas fuel offers a convenient and reliable fuel source via the natural gas pipeline and distribution infrastructure. Lean engines enable better fuel efficiency and lower operating costs; however, NOx emissions from lean engines are difficult to control. Technologies that reduce NOx in lean exhaust are desired to enable broader use of efficient lean engines. Lean NOx trap catalysts have demonstrated greater than 90% NOx reduction in lean exhaust from engines operating with gasoline, diesel, and natural gas fuels. In addition to the clean nature of the technology, lean NOx traps reduce NOx with the fuel source of the engine thereby eliminating the requirement for storage and handling of secondary fuels or reducing agents. A study of lean NOx trap catalysts for lean natural gas engines is presented here. Testing was performed on a Cummins C8.3G (CG-280) engine on a motor dynamometer. Lean NOx trap catalysts were tested for NOx reduction performance under various engine operating conditions, and the utilization of natural gas as the reductant fuel source was characterized. Engine test results show that temperature greatly affects the catalytic processes involved, specifically methane oxidation and NOx storage on the lean NOx trap. Additional studies on a bench flow reactor demonstrate the effect of precious metal loading (a primary cost factor) on lean NOx trap performance at different temperatures. Results and issues related to the potential of the lean NOx trap technology for large-bore engine applications will be discussed.

Download or read book Experimental Studies of NOx Storage and Reduction on Lean NOx Traps written by Prasanna R. Dasari and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Stricter emission standards have driven the research and development of several emission aftertreatment technologies like selective catalytic reduction (NH3-SCR) and lean NOX trap (LNT) technology. On an NH3-SCR catalyst, NH3 is injected into the exhaust, which then selectively reduces NOx to N2. During the LNT process, NOX is stored on an alkali earth oxide during the lean phase, forming surface nitrite/nitrate species, which are then reduced to N2 over precious metals during periodic "rich" operation. A combined LNT-SCR hybrid system promises to be more cost-effective and operates by utilizing NH3 formed during the rich phase operation of LNT to reduce NOx that breakthroughs LNT on the SCR catalyst downstream. An experimental set-up was built to monitor the transient reactor temperatures and effluent gas concentrations. This work systematically investigated the production of NH3 on typical Pt-Rh/BaO/Al2O3 LNT monolithic catalysts during the reduction of NOx by CO in the presence of excess water without any molecular H2 being fed to the system; under both steady-state and cyclic operation conditions. The objective was to determine the effect of various operating parameters and the involvement of intermediate species on the mechanism leading to NH3 formation and NOx reduction. Under steady-state conditions, H2 formed by wgs reaction plays a dominant role in reducing NOx to NH3. However, under cyclic operation conditions, hydrolysis of intermediate isocyanate species is shown to be the leading route to NH3 formation. An extensive study of the NOX storage mechanism and the impact of CO2 were conduced at low temperatures (

Download or read book NOx Removal by LNT SCR Dual layer Catalysts written by Yi Liu and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The increasingly strict emission standards have driven the progress of NOx storage and reduction (NSR) technology. NOx is stored in a lean NOx trap (LNT) catalyst during fuel-lean mode and reduced to N2 during fuel-rich mode. First, we investigated the impact of ceria on NSR in an Pt/Ce LNT catalyst. The physisorbed oxygen over the ceria-containing LNT catalyst led to a spatio-temporal temperature rise in the monolith upstream after the cyclic introduction of H2/CO to a pre-oxidized catalyst. The stored oxygen over ceria enhanced NO storage by in-situ NO2 formation, while it competed with NO2 for storage sites. During the NOx reduction over the Pt/Ceria, the Pt surface purgation was the first step and the oxygen reduction preceded the NOx reduction. Second, we studied the NSR by dual-layer catalysts consisting of a selective catalytic reduction (SCR) catalyst layer on top of a LNT catalyst. During periodic switching between lean and rich feeds, the LNT layer reduced NOx to N2 and NH3. The SCR layer trapped the latter leading to additional NOx reduction. The dual-layer catalysts exhibited high N2 selectivity and low NH3 selectivity over the temperature range of 150-400 oC. The NOx conversion was incomplete due to undesired NH3 oxidation. The dual-layer catalyst has a higher NOx conversion and N2 selectivity than the LNT catalyst when H2O and CO2 were present in the feed. Ceria was used to adjust the dual-layer catalyst performance. The ceria addition increased NOx storage capacity, promoted hydrothermal durability and mitigated CO poisoning. However, ceria decreased the high-temperature NOx conversion by promoting NH3 oxidation. Ceria zoning led to the highest NOx reduction for both low- and high- temperatures due to the beneficial interaction of ceria and H2. The impact of catalyst design and operation strategy was evaluated. The low-temperature NOx conversion of an aged dual-layer catalyst was increased by a high SCR catalyst loading. The ratio of lean to rich feed duration and the total cycle time were optimized to improve the NOx conversion. The results suggest the dual-layer catalyst could be used to reduce precious metal loading and improve the fuel economy.

Download or read book NOx Emission Control Technologies in Stationary and Automotive Internal Combustion Engines written by B. Ashok and published by Elsevier. This book was released on 2021-11-09 with total page 488 pages. Available in PDF, EPUB and Kindle. Book excerpt: NOx Emission Control Technologies in Stationary and Automotive Internal Combustion Engines: Approaches Toward NOx Free Automobiles presents the fundamental theory of emission formation, particularly the oxides of nitrogen (NOx) and its chemical reactions and control techniques. The book provides a simplified framework for technical literature on NOx reduction strategies in IC engines, highlighting thermodynamics, combustion science, automotive emissions and environmental pollution control. Sections cover the toxicity and roots of emissions for both SI and CI engines and the formation of various emissions such as CO, SO2, HC, NOx, soot, and PM from internal combustion engines, along with various methods of NOx formation. Topics cover the combustion process, engine design parameters, and the application of exhaust gas recirculation for NOx reduction, making this book ideal for researchers and students in automotive, mechanical, mechatronics and chemical engineering students working in the field of emission control techniques. Covers advanced and recent technologies and emerging new trends in NOx reduction for emission control Highlights the effects of exhaust gas recirculation (EGR) on engine performance parameters Discusses emission norms such as EURO VI and Bharat stage VI in reducing global air pollution due to engine emissions

Download or read book Lean NOx Reduction for Natural Gas Vehicle Applications written by and published by . This book was released on 2008 with total page 99 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Lean NOx Trap Selective Catalytic Reduction System for Controlling the NOx Emissions from a Diesel Engine written by Joseph R. Theis and published by . This book was released on 2006 with total page 442 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Lean Gasoline Engine Reductant Chemistry During Lean NOx Trap Regeneration written by and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Lean NOx Trap (LNT) catalysts can effectively reduce NOx from lean engine exhaust. Significant research for LNTs in diesel engine applications has been performed and has led to commercialization of the technology. For lean gasoline engine applications, advanced direct injection engines have led to a renewed interest in the potential for lean gasoline vehicles and, thereby, a renewed demand for lean NOx control. To understand the gasoline-based reductant chemistry during regeneration, a BMW lean gasoline vehicle has been studied on a chassis dynamometer. Exhaust samples were collected and analyzed for key reductant species such as H2, CO, NH3, and hydrocarbons during transient drive cycles. The relation of the reductant species to LNT performance will be discussed. Furthermore, the challenges of NOx storage in the lean gasoline application are reviewed.

Download or read book Lean NOx Reduction by Alternative Fuels written by Sara Erkfeldt and published by . This book was released on 2011 with total page 70 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Lean Engine NOx Control written by and published by . This book was released on 2003 with total page 152 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work presents papers from the sessions on gasoline lean NOx technologies and non-thermal plasma, held during a March 2003 meeting. Some specific topics include NOx release characteristics of lean NOx traps during rich purges, temperature impact on modeling and control of lean NOx traps, improve

Download or read book NOx Pollutants from Diesel Vehicles and Trends in the Control Technologies written by İbrahim Aslan Reşitoğlu and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nowadays, climate change that caused from air pollution has become a major problem on the agenda of almost all countries around the world. Compared to other air pollutants, NOx emissions have an important share in climate change, and especially diesel vehicles are one of the most important sources for the formation of NOx pollutants. This chapter focused on NOx emissions from diesel vehicles and the trends in NOx control technologies; Exhaust Gas Recirculation (EGR), Lean NOx trap (LNT) and Selective Catalytic Reduction of NOx by ammonia (NH3-SCR) and hydrocarbons (HC-SCR). The reasons of the NOx emissions, environmental effects and damages on human health, NOx emissions from diesel engines and diesel engine parameters affecting NOx emissions are handled in detail. The EGR, LNT and SCR technologies that had large reduction rates of NOx emissions and the latest developments in these systems are comprehensively explained.

Download or read book Lean NOx Reduction Over Silver alumina Catalysts written by Hannes Kannisto and published by . This book was released on 2010 with total page 50 pages. Available in PDF, EPUB and Kindle. Book excerpt: