Download or read book NOx Trap Catalyst Technologies to Attain 99 5 NOx Reduction Efficiency for Lean Burn Gasoline Engine Application written by Kinichi Iwachido and published by . This book was released on 2009 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 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 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 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 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 514 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book will be the first to comprehensively present the current research on catalysts used for NOx abatement in lean exhausts.
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 Lean NOx Trap Catalysis for Lean Natural Gas Engine Applications written by and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Distributed energy is an approach for meeting energy needs that has several advantages. Distributed energy improves energy security during natural disasters or terrorist actions, improves transmission grid reliability by reducing grid load, and enhances power quality through voltage support and reactive power. In addition, distributed energy can be efficient since transmission losses are minimized. One prime mover for distributed energy is the natural gas reciprocating engine generator set. Natural gas reciprocating engines are flexible and scalable solutions for many distributed energy needs. The engines can be run continuously or occasionally as peak demand requires, and their operation and maintenance is straightforward. Furthermore, system efficiencies can be maximized when natural gas reciprocating engines are combined with thermal energy recovery for cooling, heating, and power applications. Expansion of natural gas reciprocating engines for distributed energy is dependent on several factors, but two prominent factors are efficiency and emissions. Efficiencies must be high enough to enable low operating costs, and emissions must be low enough to permit significant operation hours, especially in non-attainment areas where emissions are stringently regulated. To address these issues the U.S. Department of Energy and the California Energy Commission launched research and development programs called Advanced Reciprocating Engine Systems (ARES) and Advanced Reciprocating Internal Combustion Engines (ARICE), respectively. Fuel efficiency and low emissions are two primary goals of these programs. The work presented here was funded by the ARES program and, thus, addresses the ARES 2010 goals of 50% thermal efficiency (fuel efficiency) and
Download or read book Nitrogen oxides NOx why and how they are controlled written by and published by DIANE Publishing. This book was released on 1999 with total page 57 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Passive Ammonia SCR Catalyst System for NOx Abatement from Lean burn Gasoline Engines written by Vitaly Y. Prikhodko and published by . This book was released on 2018 with total page 135 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation summarizes experimental and computational observations from investigations of a selective catalytic reduction (SCR) system for reducing nitrogen oxides (NOx) in lean gasoline engine exhaust based on utilizing ammonia (NH3) generated by a three-way catalyst (TWC) during brief periods of fuel-rich engine operation. NH3 released from the TWC is stored and available to reduce NOx on a downstream SCR catalyst during subsequent periods of lean engine operation. The experimental results include high-speed measurements of transient NH3 formation on the TWC monolith catalysts, as the catalysts were exposed to lean gasoline engine exhaust from a commercial engine. In addition to the experimental investigations, dynamic computational simulations of NH3 generation on the TWC catalyst were implemented to provide more detailed information about NH3 generation on TWCs based on available reaction kinetic mechanisms. Based on the experimental and computational results, estimates of the potential fuel efficiency gains and emissions relevant to simulated drive cycles indicate that passive SCR can potentially achieve significant fuel efficiency benefits while still meeting regulated NOx emissions limits for vehicles powered by lean gasoline engines. However, optimal performance of the system will most likely require development of emission control methods that include accurate models for SCR catalyst NH3 storage and reaction under realistic drive-cycle transients.
Download or read book Studies on the Reduction of Nitrous Oxide Formation in NOx trap Catalysts written by Javier Mena Casanova and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Current society has become more concerned about being environmentally friendly. Catalytic gas after treatment is one of the solutions adopted to reduce pollutant emissions from a combustion engine. A Three Way NOx Storage Catalytic Converter (TWNSC) is a new development of Daimler AG together with Umicore AG [1]. It consists of a Catalyst with some of the main properties of a Three Way Catalyst (TWC) together with NOx storage capacity (lean-NOx trap). This catalyst is used in Otto direct-injection engines with lean/rich operation mode. This technology can reduce fuel consumption in a range of 10%. During lean engine operation time, high quantities of Nitrogen Oxides (NOx) are generated. In presence of a TWNSC, this NOx can be stored. When the engine changes to rich operating mode, the amount of NOx in exhaust gases decreases become rich of unburned hydrocarbons (HC), hydrogen (H2) and carbon monoxide (CO) that can reduce the NOx stored. However, during NOx reduction, formation of undesired byproducts occur. That is the case of nitrous oxide (N2O) and ammonia (NH3). In this Master thesis, studies on the reduction of nitrous oxide formation in Three Way NOx Storage Catalytic Converter are performed. Studies on N2O formation during catalyst performance have not been widely studied and published. In this master thesis, lean/rich experimentations on two new TWNSC (catalyst A and B) are performed to find conditions in which N2O formation can be reduced. Experiments are performed in a test bench where lean gases are provided by a 1- cylinder-engine and rich gases from synthetic gas mixtures. At the beginning of the master thesis, two preliminary investigations are performed. The first consists of the calculation of Oxygen Storage Capacity (OSC) of a cylindrical sample (25 mm diameter, 30 mm length) of catalyst A and B. The results of the experiment show that catalyst B has less Oxygen Storage Capacity. The experiment consisted on applying a flow of 12,5 l/min of Oxygen (O2) in nitrogen (N2) (0,4% by volume) through the previously reduced sample. An average of 0,3 g./l.cat. less oxygen is stored in catalyst B for temperatures of 300, 350 and 400 oC. At 300oC, catalyst A stores 1,44 g/l.cat. compared to the 0,93 g/l.cat. in catalyst B. The second preliminary investigation consists of determining the temperature in which the Diesel Oxidation Catalyst (DOC) in reactor 1 has to operate. The objective of this DOC is to oxidize the HC and maintain the original NO2/NOx ratio from the engine exhaust gases. During lean mode, gases from a 1-cylinder-engine (Hatz-motor [2]) are used. NOx and HC concentrations are analyzed for a range of temperatures from 150 to 650 oC. It is concluded that a temperature of 620 oC has to be reached in reactor one to get rid of HC and maintain the NO2/NOx ratio of the bypass exhaust gases (2% of NO2 in NOx). After the preliminary investigations, the first objective is getting to know the basic performance of the two different TWNSC. Lean/rich experimentations are performed on both samples A and B at the range of temperatures from 150oC to 450oC. Lean/rich timing is set on 120/15 seconds respectively. In addition, three different rich gas mixtures (lambdas 0,95, 0,9 and 0,82) have been used for the rich mode. Results show that for lambda 0,95 less N2O is generated (0,06 g/l.cat. at 300oC in catalyst A). The minimum N2O detected is at catalyst B at temperatures of 400 and 450oC (0,01 and 0,00 g/l.cat.). The main part of the Master Thesis consists of four different experimentations that have the objective to find any reduction in N2O formation: 1. N2O formation studies with lean/rich experimentations at modified TWNSC catalysts. Instead of the 30 mm sample previously used, two 15 mm samples are used together. Modifications are applied on the first 15 mm sample and consist on five perforations (2 mm diameter) and the introduction of an uncoated central part section. These modifications try to increase reductants velocity during rich mode. Results show a decrease in N2O formation in the experiment with 15 mm uncoated catalyst A together with another 15 mm catalyst A. An average of 2,8 g/l.cat. of N2O reduction is obtained at temperature of 300oC. In addition, an increase of NOx conversion efficiency has been detected: for the same sample and temperature an average increase of 20% NOx performance 2. N2O formation studies with lean/rich experimentations at a combination of catalysts A and B together. It is concluded that the combination of catalyst A and B does not have a beneficial effect on N2O formation. 3. N2O formation studies with lean/rich experimentations with variation of rich time period. The objective is to see if the reduction of rich time period has an effect on N2O formation. 4. Lean/rich experimentations with variation of the lambda during rich period. The objective is to see if a reduction in N2O is obtained with these variations. For low temperatures (150oC and 200oC) a diminution in N2O formation is appreciated (0,05 g/l.cat to 0,04 g./l.cat at 150oC for 30 mm TWNSCA with uncoated section). This Master Thesis represents a base line study for further investigations on N2O formation on TWNSC. Catalyst modifications are a feasible solution for N2O diminution as well as NOx conversion efficiency. These results encourage further experimentations with these current and other new catalyst modifications. Variation of lambda during rich period and variation of the rich time period are variables that can have a relevant role.
Download or read book Mitigation of Sulfur Effects on a Lean NOx Trap Catalyst by Sorbate Reapplication written by and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Lean NOx trap catalysis has demonstrated the ability to reduce NOx emissions from lean natural gas reciprocating engines by>90%. The technology operates in a cyclic fashion where NOx is trapped on the catalyst during lean operation and released and reduced to N2 under rich exhaust conditions; the rich cleansing operation of the cycle is referred to as "regeneration" since the catalyst is reactivated for more NOx trapping. Natural gas combusted over partial oxidation catalysts in the exhaust can be used to obtain the rich exhaust conditions necessary for catalyst regeneration. Thus, the lean NOx trap technology is well suited for lean natural gas engine applications. One potential limitation of the lean NOx trap technology is sulfur poisoning. Sulfur compounds directly bond to the NOx trapping sites of the catalyst and render them ineffective; over time, the sulfur poisoning leads to degradation in overall NOx reduction performance. In order to mitigate the effects of sulfur poisoning, a process has been developed to restore catalyst activity after sulfur poisoning has occurred. The process is an aqueous-based wash process that removes the poisoned sorbate component of the catalyst. A new sorbate component is reapplied after removal of the poisoned sorbate. The process is low cost and does not involve reapplication of precious metal components of the catalyst. Experiments were conducted to investigate the feasibility of the washing process on a lean 8.3-liter natural gas engine on a dynamometer platform. The catalyst was rapidly sulfur poisoned with bottled SO2 gas; then, the catalyst sorbate was washed and reapplied and performance was re-evaluated. Results show that the sorbate reapplication process is effective at restoring lost performance due to sulfur poisoning. Specific details relative to the implementation of the process for large stationary natural gas engines will be discussed.
Download or read book Emissions Reduction written by A. Tomita and published by Elsevier. This book was released on 2001-12-18 with total page 340 pages. Available in PDF, EPUB and Kindle. Book excerpt: Over the past decade the topic of emissions reduction and control has remained an important area of research due to the enforcement of various Government policies in an attempt to minimize the impact on the environment. One area in which a great deal of research has been conducted to address this policy is NOx/SOx suppression. However, despite the progress that has been made over this time period, further research into the most effective method of reducing NOx/SOx emissions is still urgently required. In developed countries, a more stringent requirement in the level of emissions (such as is NOx/SOx component of less than 10ppm) will be enforced in the near future. Developing countries will also need a new technology that is effective and that is suited to each countries needs. Additional research and development efforts are thus necessary to meet such requirements. This compendium contains a collection of key papers themed around NOx/SOx emissions from combustion of hydrocarbon resources and the attempts to secure an efficient and effective method for reducing these emissions. These key papers are taken from the journals Fuel, Fuel Processing Technology and Progress in Energy and Combustion Science.
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 Performance of a Perovskite based Lean NOX trap Catalyst and Effects of Thermal Degradation and Sulfur Poisoning written by Crystle Constantinou and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Increases in vehicle exhaust emission regulations have led to research, development and improvements in catalytic converter technologies for gasoline-powered vehicles since the 1970s. Nowadays, there are strict regulations and standards for diesel engines as well, and one of the regulated species is nitrogen oxides (NOX). The lean NOX trap (LNT) catalyst has been studied and developed for use in lean burn (of which diesel is an example) engine exhaust as a technology to reduce NOX to N2. Typical LNT catalysts contain Pt, which catalyzes NO oxidation and NOX reduction, and an alkali or alkaline earth material for NOX storage via nitrate formation. The catalyst is operated in a cyclic mode, with one phase of the cycle under oxidizing conditions where NOX is trapped, and a second phase, which is reductant-rich relative to O2, where stored NOX is reduced to N2. A recently developed catalyst uses a perovskite material as part of the LNT formulation for the oxidation reactions thereby eliminating the need for Pt in a LNT. This catalyst does include Pd and Rh, added to accommodate hydrocarbon oxidation and NO reduction, respectively. Ba was used as the trapping component, and Ce was also part of the formulation. NO oxidation kinetics over the fully-formulated and bare perovskite material were determined, with NO, O2 and NO2 orders being at or near 1, 1 and -1, respectively for both samples. The fully-formulated sample, which contains Ba supported on the perovskite, was evaluated in terms of NOX trapping ability and NOX reduction as a function of temperature and reduction phase properties. Trapping and overall performance increased with temperature to 375°C, primarily due to improved NO oxidation, as NO2 is more readily trapped, or better diffusion of nitrates away from the initial trapping sites. At higher temperatures nitrate stability decreased, thus decreasing the trapping ability. At these higher temperatures, a more significant amount of unreduced NOX formed during the reduction phase, primarily due to nitrate instability and decomposition and the relative rates of the NOX and oxygen storage (OS) components reduction reactions. Most of the chemistry observed was similar to that observed over Pt-based LNT catalysts. However, there were some distinct differences, including a stronger nitrate diffusion resistance at low temperature and a more significant reductant-induced nitrate decomposition reaction. The perovskite-based lean NOX trap (LNT) catalyst was also evaluated after thermal aging and sulfur exposure. NO oxidation, NOX trapping ability and NOX reduction as a function of temperature and reduction phase properties were evaluated. Similar overall performance trends were seen before and after degradation, however lower performance after thermal aging and sulfur exposure were seen due to sintering effects and possible build-up of S species. Although performance results show that most of the sulfur was removed after desulfation, some sulfur remained affecting the trapping and reduction capabilities as well as the water gas shift (WGS) extent at lower temperatures. The Oxygen storage capacity (OSC) on the other hand was maintained after the catalyst was exposed to thermal aging and sulfur poisoning then desulfation, all of which suggest that the perovskite or Pd components were irreversibly poisoned to some extent.
Download or read book Cerium ferrierite Catalyst Systems for Reduction of NOx in Lean Burn Engine Exhaust Gas written by Germaine Seijger and published by IOS Press. This book was released on 2002 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt: Contents of this Doctoral Dissertation include: NOx emission reduction from lean burn engines, automotive exhaust gas emissions, Reactions of NOx in the atmosphere Engine market share and sales trends, Ferrierite characteristics, synthesis and application, Characteristics of the group of FER framework structures, Screening of silver and cerium exchanged zeolite catalysts for the lean burn reduction of NOx with propene, Hydrocarbon NOx reduction in lean burn exhaust gas over Ce-FER catalysts, Approach to the kinetics of NOx reduction with propene over Ce-H-Ferrierite, In SITU preparation of ferrierite coatings on cordierite honeycomb supports, Concluding remarks
