Download or read book Catalysts for Direct Decomposition of NOx in Exhausts written by and published by . This book was released on 2000 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: Eltron Research, Inc., is pursuing the rational development of catalysts for direct (reagentless) decomposition of NOx. This is the most economical imaginable approach for post-combustion removal of nitrogen oxides because costs for reagent and reagent delivery (i.e., ducting, etc.) are eliminated, and catalysts demonstrating activity to the present time are inexpensive ($1-$4/lb). The decomposition of nitrogen oxides in simulated exhaust streams over new brownmillerite catalysts has been examined in a range of temperatures and residence times. Results are indicative of the occurrence of reagentless activity in gas streams containing up to 16 percent oxygen. Performance was nonmonotonic in temperature, with an activity maximum occurring between 550 and 600 deg C. For example, up to 90% conversion of NOx at 250 deg C and 130,000/h has been attained. Using CO as a reductant at 800,000/h and 1000 deg C , one catalyst removed 16 percent of 477 ppm NO in a stream also containing 16 percent oxygen. These results suggest the potential efficacy of the catalysts for the direct decomposition of nitrogen oxides in high-temperature (400-1000 deg C) exhaust gases in, e.g., gas turbine and diesel engines. In addition, the catalysts were found to be effective at oxidizing CO. The enhancement of activity obtained using carbon monoxide is particularly relevant in such applications.

Download or read book New and Future Developments in Catalysis written by Yasushi Sekine and published by Elsevier Inc. Chapters. This book was released on 2013-07-17 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 Catalysis and Automotive Pollution Control IV written by N. Kruse and published by Elsevier. This book was released on 1998-05-29 with total page 719 pages. Available in PDF, EPUB and Kindle. Book excerpt: In spite of the energy crises and the recession, there has been a global, explosive growth in the amount of motor vehicles. In the past 50 years, the amount has increased from 50 to 700 million vehicles. For economical reasons they will probably continue to be used for a considerable number of years, despite the poor yield of internal combustion engines resulting in the inevitable production of some gaseous pollutants. The subsequent increase of gaseous pollutants in our atmosphere caused by exhaust gas from automobiles has enhanced the problem of the elimination of these pollutants produced by internal combustion engines. Catalysis has proven to be the best solution to lower the content of exhaust gas in pollutants. As its predecessors, CAPoC4 proved to be a suitable platform for discussing technological improvements and developments along with future perspectives and challenges. In the light of new results and further legislative regulations, the following topics were intensely discussed: *low light-off behaviour based on improved catalysts and substrate formulations *efficient adsorber systems for storage of hydrocarbon emissions *electrically heated catalyst systems ahead the main catalyst or, alternatively, close coupled catalysts (at the manifold of the engine) • lean DeNOx catalysts allowing for decomposition of NOx in the oxygen-rich exhaust of direct injection gasoline engines and high speed injection diesel engines or, alternatively, NOx trapping/reduction in a hybrid approach * collection and destruction of dry particulates or soot. There is no doubt that clean vehicle technology is a vital part of improving air quality. Challenges remain and call for technological answers. Catalytic air pollution control is still an area providing a considerable incentive for innovative work.

Download or read book Catalytic Decomposition of Nitric Oxide and Carbon Monoxide Gases Using Nanofiber Based Filter Media written by Soo-Jin Park and published by . This book was released on 2008 with total page 259 pages. Available in PDF, EPUB and Kindle. Book excerpt: The main sources of NOx are diesel engines, automotives, electric utilities, other industrial, commercial, and residential sources that burn fuels at high temperature. The control and abatement of NOx emissions are important because of their harmful effects on the human body and the environment. The strict regulations of NOx emissions and the growing demand for power compel new design of catalytic materials for pollution removal. The most common method for car exhaust NOx treatment involves wet impregnation of noble metals on ceramic substrates. In this work, catalytic nanoparticles doped on nanofiber enhanced ceramic fibrous filter medium structure are developed as an alternative method. The noble metals, palladium, platinum and rhodium doped ceramic nanofibers, are synthesized using electrospinning and are incorporated into the micro-fibrous filter. We have discovered ceramic nanofiber containing noble metals also work in liquid phase catalysis by converting styrene to ethylbenzene at room temperature and atmospheric pressure. The reaction temperature is varied and the filters are tested for decomposition of nitric oxide and carbon monoxide using nanofiber based fibrous filter. Carbon dioxide, nitrogen and nitrous oxide gases were produced. Produced nitrous oxide gas was consumed by reacting with carbon monoxide. The efficiency of the catalytic fibrous filter was similar to commercial catalytic converter by adding of smaller amount of catalyst doped on alumina microfibers. As the amount of catalyst in the fibrous filter media increases the temperature at which all NO disappears decreases. As the inlet concentration of NO gas decreases, all NO disappears from the outlet at a lower temperature. As the face velocity through the fibrous filter media increases, efficiency becomes lower as the residence time of gases through the media decreases. We also tested a catalytic fibrous filter media containing Pd, Pt and Rh, and the performance is similar to that of catalytic convertor. Analytical models are developed to study the performance of filters for isothermal nitric oxide and carbon monoxide gas reaction. The kinetic parameters for the model were determined using the Genetic Algorithm (GA) computer program to determine species concentrations as a function of position. Model and experimental results showed that the decomposition temperature of nitric oxide gas decreases by lowering the inlet gas concentration and increasing of catalyst concentration in the nanofibers. Also a non-isothermal model was developed for direct nitric oxide decomposition to predict temperature and concentration profiles along the filter length.

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 Selective Catalytic Reduction of NOx written by Oliver Kröcher and published by MDPI. This book was released on 2018-12-14 with total page 281 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a printed edition of the Special Issue "Selective Catalytic Reduction of NO_x" that was published in Catalysts

Download or read book Catalysis and Automotive Pollution Control IV written by N. Kruse and published by Elsevier Science. This book was released on 1998-05-29 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: In spite of the energy crises and the recession, there has been a global, explosive growth in the amount of motor vehicles. In the past 50 years, the amount has increased from 50 to 700 million vehicles. For economical reasons they will probably continue to be used for a considerable number of years, despite the poor yield of internal combustion engines resulting in the inevitable production of some gaseous pollutants. The subsequent increase of gaseous pollutants in our atmosphere caused by exhaust gas from automobiles has enhanced the problem of the elimination of these pollutants produced by internal combustion engines. Catalysis has proven to be the best solution to lower the content of exhaust gas in pollutants. As its predecessors, CAPoC4 proved to be a suitable platform for discussing technological improvements and developments along with future perspectives and challenges. In the light of new results and further legislative regulations, the following topics were intensely discussed: *low light-off behaviour based on improved catalysts and substrate formulations*efficient adsorber systems for storage of hydrocarbon emissions*electrically heated catalyst systems ahead the main catalyst or, alternatively, close coupled catalysts (at the manifold of the engine). lean DeNOx catalysts allowing for decomposition of NOx in the oxygen-rich exhaust of direct injection gasoline engines and high speed injection diesel engines or, alternatively, NOx trapping/reduction in a hybrid approach* collection and destruction of dry particulates or soot. There is no doubt that clean vehicle technology is a vital part of improving air quality. Challenges remain and call for technological answers. Catalytic air pollution control is still an area providing a considerable incentive for innovative work.

Download or read book Tableaux modernes Aquarelles Pastels Gouaches Dessins Sculptures written by and published by . This book was released on 1954 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book New and Future Developments in Catalysis written by Steven L Suib and published by Newnes. This book was released on 2013-07-17 with total page 631 pages. Available in PDF, EPUB and Kindle. Book excerpt: New and Future Developments in Catalysis is a package of seven books that compile the latest ideas concerning alternate and renewable energy sources and the role that catalysis plays in converting new renewable feedstock into biofuels and biochemicals. Both homogeneous and heterogeneous catalysts and catalytic processes will be discussed in a unified and comprehensive approach. There will be extensive cross-referencing within all volumes.The various sources of environmental pollution are the theme of this volume. The volume lists all current environmentally friendly catalytic chemical processes used for environmental remediation and critically compares their economic viability. Offers in-depth coverage of all catalytic topics of current interest and outlines future challenges and research areas A clear and visual description of all parameters and conditions, enabling the reader to draw conclusions for a particular case Outlines the catalytic processes applicable to energy generation and design of green processes

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 Multi Stage Selective Catalytic Reduction of NOx in Lean Burn Engine Exhaust written by B. Penetrante and published by . This book was released on 1997 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent Studies suggest that the conversion of NO to NO2 is an important intermediate step in the selective catalytic reduction (SCR) of NOx to N2. These studies have prompted the development of schemes that use an oxidation catalyst to convert NO to NO2, followed by a reduction catalyst to convert NO2 to N2. Multi-stage SCR offers high NOx reduction efficiency from catalysts that, separately, are not very active for reduction of NO, and alleviates the problem of selectivity between NO reduction and hydrocarbon oxidation. A plasma can also be used to oxidize NO to NO2. This paper compares the multi-stage catalytic scheme with the plasma-assisted catalytic scheme for reduction of NOx in lean-burn engine exhausts. The advantages of plasma oxidation over catalytic oxidation are presented.

Download or read book Catalysis written by James J Spivey and published by Royal Society of Chemistry. This book was released on 2022-07-07 with total page 273 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume looks at modern approaches to catalysis and reviews the extensive literature. Chapters highlight microkinetic modeling, encapsulated metals for confined catalysis, recent advances on the direct decomposition of NOx and heteropolyacid catalysts. There is also a chapter reviewing methods for estimating adsorption energies on catalytic surfaces, which will provide information from both fundamental and technological points of view. Appealing broadly to researchers in academia and industry, the detailed chapters bridge the gap from academic studies in the laboratory to practical applications in industry, not only for the catalysis field, but also for environmental protection. The book will be of great benefit to any researcher wanting a succinct reference on developments in this area now and looking to the future.

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

Download or read book Structured Catalysts and Reactors written by Andrzej Cybulski and published by CRC Press. This book was released on 2005-11-02 with total page 828 pages. Available in PDF, EPUB and Kindle. Book excerpt: Interest in structured catalysts is steadily increasing due to the already proven, as well as potential, advantages of these catalysts. Updating the comprehensive coverage of the first edition published in 1998 with the latest science and applications, Structured Catalysts and Reactors, Second Edition gives detailed information on all aspect

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 Urea SCR Technology for deNOx After Treatment of Diesel Exhausts written by Isabella Nova and published by Springer Science & Business Media. This book was released on 2014-03-14 with total page 715 pages. Available in PDF, EPUB and Kindle. Book excerpt: Urea-SCR Technology for deNOx After Treatment of Diesel Exhausts presents a complete overview of the selective catalytic reduction of NOx by ammonia/urea. The book starts with an illustration of the technology in the framework of the current context (legislation, market, system configurations), covers the fundamental aspects of the SCR process (catalysts, chemistry, mechanism, kinetics) and analyzes its application to useful topics such as modeling of full scale monolith catalysts, control aspects, ammonia injections systems and integration with other devices for combined removal of pollutants.