Download or read book Catalysts for Low Temperature Conversion of Nitrogen Oxides written by Martin Busch and published by . This book was released on 2015 with total page 174 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Catalysts for low temperature conversion of nitrogen oxides written by Martin Busch and published by Cuvillier Verlag. This book was released on 2015-06-02 with total page 174 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nitrogen oxides are a major threat to human health and largely released by Diesel engines. The present book describes the preparation and characterization of appropriate catalyst systems for low temperature removal (150 - 400°C) and conversion of nitrogen oxides. The presented catalysts include commercially available activated carbon and zeolite supports, infiltrated with iron, copper, manganese and their oxides. The investigated catalysts adsorb and convert nitrogen dioxide almost completely and convert it quickly subsequently into the less toxic nitric oxide and nitrous oxide. Some eventually release nitrogen and oxygen, thus outperforming even the well-known Cu-ZSM-5 catalyst at low temperature. Stickoxide zählen zu den wichtigsten Umweltgiften und werden zu einem großen Anteil durch Dieselmotoren freigesetzt. Dieses Buch beschreibt die Herstellung und Charakterisierung von Katalysatorsysteme für die Niedertemperatur-Umsetzung (150 - 400°C) von Stickoxiden. Zu den vorgestellten Katalysatoren gehören kommerziell verfügbare Aktivkohle und Zeolith-Materialien, welche mit Eisen, Kupfer, Mangan und deren Oxiden infiltriert wurden. Alle untersuchten Katalysatorsysteme absorbieren Stickoxide rasch und setzen diese anschließend fast vollständig in die weit weniger toxischen Gase Stickstoffmonoxid und Distickstoffmonoxid um. Einige der untersuchten Katalysatorsystemen setzen schließlich Sauerstoff und Stickstoff frei und zeigen bei niedrigen Temperaturen sogar eine bessere Performance als der bereits gut bekannte Cu-ZSM-5 Katalysator.
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 NOx" that was published in Catalysts
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 490 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 DEVELOPMENT OF IMPROVED CATALYSTS FOR THE SELECTIVE CATALYTIC REDUCTION OF NITROGEN OXIDES WITH HYDROCARBONS written by and published by . This book was released on 2001 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt: Significant work has been done by the investigators on the cerium oxide-copper oxide based sorbent/catalysts for the combined removal of sulfur and nitrogen oxides from the flue gases of stationary sources. A relatively wide temperature window was established for the use of alumina-supported cerium oxide-copper oxide mixtures as regenerable sorbents for SO2 removal. Preliminary evaluation of these sorbents as catalysts for the selective reduction of NO(subscript x) gave promising results with ammonia, but indicated low selectivity when methane was used as the reductant. Since the replacement of ammonia by another reductant is commercially very attractive, in this project, four research components will be undertaken. The investigation of the reaction mechanism, the first component, will help in the selection of promoters to improve the catalytic activity and selectivity of the sorbents in the SCR with methane. This will result in new catalyst formulations (second component). If this research is successful, the combined SO2-NO(subscript x) removal process based on alumina-supported copper oxide-ceria sorbent/catalysts will become very attractive for commercial applications. The objective of the third component of the project is to develop an alternative SCR process using another inexpensive fuel, residual fuel oil, instead of natural gas. This innovative proposal is based on very scant evidence concerning the good performance of coked catalysts in the selective reduction of NO and if proven to work the process will certainly be commercially viable. The fourth component of the project involves our industrial partner TDA Research, and the objective is to evaluate long-term stability and durability of the prepared sorbent/catalysts. In the first year of the project, the catalysts were investigated by the temperature-programmed reduction (TPR) technique. The results from TPR indicated that the interaction with support appears to promote reduction at lower temperatures. Copper oxide in excess of monolayer coverage reduces at temperatures close to the reduction temperature of the unsupported copper oxide. Increased dispersion increases the support effect. Low activity of ceria in NO reduction may be due to its resistance to reduction at low temperatures.
Download or read book Past and Present in DeNOx Catalysis From Molecular Modelling to Chemical Engineering written by Pascal Granger and published by Elsevier. This book was released on 2007-12-15 with total page 419 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book offers an overview of the state of the art in the field of DeNOx catalysis in order to focus novel orientations, new technological developments, from laboratory to industrial scale. A particular attention has been paid towards the implementation of catalytic processes for minimising NOx emissions either from stationary or mobile sources under lean condition to meet future standard regulations of NOx emissions. In the first part of this book, critical aspects reported in the literature which usually make difficult the achievement of efficient catalytic technologies in those conditions are summarised and analysed in order two separate new perspectives. The second part deals with fundamental aspects at molecular level. A better understanding of the reactions involved under unsteady-state conditions is probably a pre-requisite step for improving the performances of the actual processes or developing original ones. The development of powerful in situ spectroscopic techniques is of fundamental interest for kinetic modelling. Correlations between spectroscopic and kinetic data with those obtained from theoretical calculations are reported. Some illustrations emphasise the fact that these comparisons may help in determining the nature of the catalytic active sites and building predictive tools for simulations under running conditions. The latter part of this book will be illustrated by different practical approaches covering various aspects related to the catalysts preparation and the development of alternative technologies which include industrial considerations. - New technological developments for investigating catalytic reactions in transient conditions (in situ and operando spectroscopic techniques) - Concerted approaches in DeNOx catalysis - How academic aspects (kinetic, in situ spectroscopic measurements) can provide useful information for practical applications - Comparison of different approaches provided by academic and industrial partners
Download or read book BIFUNCTIONAL CATALYSTS FOR THE SELECTIVE CATALYTIC REDUCTION OF NO BY HYDROCARBONS written by and published by . This book was released on 2003 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: Novel bifunctional catalysts combining two active phases, typically Cu-ZSM-5 and a modifier, were prepared and tested for the selective catalytic reduction of nitrogen oxides using propylene in order to overcome the hindering effects of water typically seen for single-phase catalysts such as Cu-ZSM-5. The catalysts were made by typical preparation techniques, but parameters could be varied to influence the catalyst. The physical characterization of the materials showed that the modification phase was added strictly to the external surface of the zeolite without hindering any internal surface area. Chemical characterization by temperature programmed reactions, DRIFTS and x-ray absorption spectroscopy indicated strong interaction between the two phases, primarily producing materials that exhibited lower reduction temperatures. Two improvements in NOx reduction activity (1000 ppm NO, 1000 ppm C3H6, 2% O2, 30,000 hr-1 GHSV) were seen for these catalysts compared with Cu- ZSM-5: a lower temperature of maximum NOx conversion activity (as low at 250 C), and an enhancement of activity when water was present in the system. The use of a second phase provides a way to further tune the properties of the catalyst in order to achieve mechanistic conditions necessary to maximize NOx remediation.
Download or read book Studies of Supported Vanadium Oxide Catalysts for the Selective Catalytic Reduction of Nitrogen Oxides written by Gregory Thomas Went and published by . This book was released on 1991 with total page 428 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Supported Transition Metal Oxide Catalysts for Low temperature NH3 SCR with Improved H2O resistance written by Marcus Kasprick and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Stamtavle over Familien Dahlerup og dens Sidelinier affattet i Aaret 1882 written by and published by . This book was released on 1882 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Sanna och falska christnas k nnem rken f rn mligast af deras tal i anledning af Christi utl telse Matth 12 34 35 D r hjertat med fullt r d raf talar munnen En god m nniska b r godt fram af hjertans goda fatabur och en ond m nniska written by and published by . This book was released on 1785 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 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 NOx Reduction with Hydrocarbons Under Oxidizing Conditions Over Alumina Supported Metal Catalysts written by Erol Seker and published by . This book was released on 2000 with total page 338 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 0 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 Atlas of Zeolite Framework Types written by Ch. Baerlocher and published by Elsevier. This book was released on 2007-09-12 with total page 405 pages. Available in PDF, EPUB and Kindle. Book excerpt: Zeolite scientists, whether they are working in synthesis, catalysis, characterization or application development, use the Atlas of Zeolite Framework Types as a reference. It describes the main features of all of the confirmed zeolite framework structures, and gives references to the relevant primary structural literature. Since the last edition 34 more framwork types have been approved and are described in this new edition. A further new feature will be that characteristic building units will be listed for each of the framework types.Zeolites and their analogs are used as desiccants, as water softeners, as shape-selective acid catalysts, as molecular sieves, as concentrators of radioactive isotopes, as blood clotting agents, and even as additives to animal feeds. Recently, their suitability as hosts for nanometer spacing of atomic clusters has also been demonstrated. These diverse applications are a reflection of the fascinating structures of these microporous materials. Each time a new zeolite framework structure is reported, it is examined by the Structure Commission of the International Zeolite Association (IZA-SC), and if it is found to be unique and to conform to the IZA-SC's definition of a zeolite, it is assigned a 3-letter framework type code. This code is part of the official IUPAC nomenclature for microporous materials. The Atlas of Zeolite Framework Types is essentially a compilation of data for each of these confirmed framework types. These data include a stereo drawing showing the framework connectivity, features that characterize the idealized framework structure, a list of materials with this framework type, information on the type material that was used to establish the framework type, and stereo drawings of the pore openings of the type material. Clear stereo drawings of each of the framework types Description of the features of the framework type, allowing readers to quickly see if the framework type is suitable to their needs References to isotypic materials, readers can quickly identify related materials and consult the appropriate reference
