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 Emissions Control Catalysis written by Ioannis V. Yentekakis and published by MDPI. This book was released on 2020-06-18 with total page 448 pages. Available in PDF, EPUB and Kindle. Book excerpt: The important advances achieved over the past years in all technological directions (industry, energy, and health) contributing to human well-being are unfortunately, in many cases, accompanied by a threat to the environment, with photochemical smog, stratospheric ozone depletion, acid rain, global warming, and finally climate change being the most well-known major issues. These are the results of a variety of pollutants emitted through these human activities. The indications show that we are already at a tipping point that might lead to non-linear and sudden environmental change on a global scale. Aiming to tackle these adverse effects in an attempt to mitigate any damage that has already occurred and to ensure that we are heading toward a cleaner (green) and sustainable future, scientists around the world are developing tools and techniques to understand, monitor, protect, and improve the environment. Emissions control catalysis is continuously advancing, providing novel, multifunctional, and optimally promoted using a variety of methods, nano-structured catalytic materials, and strategies (e.g., energy chemicals recycling, cyclic economy) that enable us to effectively control emissions, either of mobile or stationary sources, improving the quality of air (outdoor and indoor) and water and the energy economy. Representative cases include the abatement and/or recycling of CO2, CO, NOx, N2O, NH3, CH4, higher hydrocarbons, volatile organic compounds (VOCs), particulate matter, and specific industrial emissions (e.g., SOx, H2S, dioxins aromatics, and biogas). The “Emissions Control Catalysis” Special Issue has succeeded in collecting 22 high-quality contributions, included in this MDPI open access book, covering recent research progress in a variety of fields relevant to the above topics and/or applications, mainly on: (i) NOx catalytic reduction from cars (i.e., TWC) and industry (SCR) emissions; (ii) CO, CH4, and other hydrocarbons removal, and (iii) CO2 capture/recirculation combining emissions control with added-value chemicals production.
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 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
Download or read book Highly Dispersed Transition Metal Oxide Catalysts Achieved on Hydroxyl rich Supports for Environmental Catalysis written by Murtadha Almousawi and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Air pollution is one of the most substantial challenges of our era. It is a major contributor to climate change and a significant health hazard contributing to increased mortality or severe illness. Environmental catalysis is one of the most sustainable and effective solutions for reducing the emissions of undesirable pollutants in the atmosphere. Nonetheless, the effectiveness of pollutant removal greatly hinges upon the catalyst employed, necessitating the urgent development of exceptionally efficient catalysts. In comparison to the commonly employed precious metal catalysts, there has been a notable surge of interest in non-noble transition metal catalysts, such as copper and nickel-based catalysts. This interest is primarily due to their abundant availability, lower cost, and their considerable activities in environmental related reactions that are comparable to those of noble metal catalysts. However, there is still a pressing need to significantly enhance their low-temperature activity to meet application requirements. Increasing the metal dispersion to create more active sites and establishing a strong interaction between metals and supports are effective strategies to improve the catalytic performance of supported metal catalysts. However, achieving these improvements using simple and scalable preparation methods has posed a considerable challenge in the material science and environmental catalysis field. In this work, using hydroxyl-rich (OH-rich) CeO2 and ZrO2 as supports and a facile incipient wetness impregnation (IWI) method, we report the successful preparation of three sets of catalysts, including CuO/CeO2, CuO/ZrO2, and Ni/CeO2, with high metal dispersion and enhanced metal-support interactions. Our findings show that these catalysts prepared using OH-rich supports exhibited superior catalytic performance in environmental-related reactions, including CO oxidation, NO reduction by CO, selective catalytic oxidation of NH3 (NH3-SCO), and dry reforming of methane (DRM), respectively. Using various experimental techniques, including X-ray diffraction (XRD), Raman spectroscopy, transmission electron microscopy (TEM), N2 physisorption, X-ray photoelectron spectroscopy (XPS), X-ray absorption spectroscopy (XAS), and in situ diffuse reflectance infrared Fourier transform spectroscopy (in situ DRIFTS), the effect of hydroxyls on Ce(OH)x and Zr(OH)x supports on the physicochemical properties of the catalysts was characterized in detail. Additionally, the structure-activity relationship and reaction mechanism on these newly developed catalysts were revealed. This study showcases the utilization of OH-rich supports to improve metal dispersion and strengthen the metal-support interaction, thereby improving the catalytic performance of supported transition metal catalysts. This research suggests that utilizing OH-rich supports holds great promise as an approach to designing highly efficient catalysts for important environmental catalysis applications.
Download or read book Low Temperature Selective Catalytic Reduction SCR of Nitric Oxide NO on Active Carbon Fibre ACF Supported Transition Metal Catalysts written by David Madill and published by . This book was released on 2002 with total page 422 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Development of Nitric Oxide Oxidation Catalysts for the Fast SCR Reaction written by Mark Crocker and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This study was undertaken in order to assess the potential for oxidizing NO to NO{sub 2} in flue gas environments, with the aim of promoting the so-called fast SCR reaction. In principle this can result in improved SCR kinetics and reduced SCR catalyst volumes. Prior to commencing experimental work, a literature study was undertaken to identify candidate catalysts for screening. Selection criteria comprised (1) proven (or likely) activity for NO oxidation, (2) low activity for SO2 oxidation (where data were available), and (3) inexpensive component materials. Catalysts identified included supported base metal oxides, supported and unsupported mixed metal oxides, and metal ion exchanged ZSM-5 (Fe, Co, Cu). For comparison purposes, several low loaded Pt catalysts (0.5 wt% Pt) were also included in the study. Screening experiments were conducted using a synthetic feed gas representative of flue gas from coal-fired utility boilers: [NO] = 250 ppm, [SO{sub 2}] = 0 or 2800 ppm, [H{sub 2}O] = 7%, [CO{sub 2}] = 12%, [O{sub 2}] = 3.5%, balance = N{sub 2}; T = 275-375 C. Studies conducted in the absence of SO{sub 2} revealed a number of supported and unsupported metal oxides to be extremely active for NO oxidation to NO{sub 2}. These included known catalysts (Co{sub 3}O{sub 4}/SiO{sub 2}, FeMnO{sub 3}, Cr{sub 2}O{sub 3}/TiO{sub 2}), as well as a new one identified in this work, CrFeO{sub x}/SiO{sub 2}. However, in the presence of SO{sub 2}, all the catalysts tested were found to be severely deactivated with respect to NO oxidation. Of these, Co{sub 3}O{sub 4}/SiO{sub 2}, Pt/ZSM-5 and Pt/CeO{sub 2} showed the highest activity for NO oxidation in the presence of SO{sub 2} (based on peak NO conversions to NO{sub 2}), although in no cases did the NO conversion exceed 7%. Reactor studies indicate there are two components to SO{sub 2}-induced deactivation of Co{sub 3}O{sub 4}/SiO{sub 2}, corresponding to an irreversible deactivation due to sulfation of the surface of the Co{sub 3}O{sub 4} phase, together with a reversible inhibition due to competitive adsorption of SO{sub 2} with NO on the catalyst. In an effort to minimize the deactivating effect of SO{sub 2} on Co{sub 3}O{sub 4}/SiO{sub 2}, two synthetic approaches were briefly examined. These consisted of (1) the incorporation of highly dispersed Co(II) ions in silica, as a non-sulfating matrix, via the sol-gel preparation of CoO-SiO{sub 2}; and (2) the sol-gel preparation of a mixed metal oxide, CoO-Nb{sub 2}O{sub 5}-SiO{sub 2}, with the aim of exploiting the acidity of the niobium oxide to minimize SO2 adsorption. While both catalysts showed almost no activity for NO oxidation in the absence of SO{sub 2}, when SO{sub 2} was present low activity was observed, indicating that SO{sub 2} acts as a promoter for NO oxidation over these materials. The kinetics of NO oxidation over Co{sub 3}O{sub 4}/SiO{sub 2}, Pt/SiO{sub 2} and Pt/CeO{sub 2} were also examined. Co{sub 3}O{sub 4}/SiO{sub 2} was found to exhibit a higher apparent activation energy for NO oxidation than the Pt catalysts, while the combined reaction order in NO and O{sub 2} for the three catalysts was very close to one. CO{sub 2} was found to have no effect on the kinetics of NO oxidation over these catalysts. The presence of H{sub 2}O caused a decrease in NO conversion for both Co{sub 3}O{sub 4}/SiO{sub 2} and Pt/CeO{sub 2} catalysts, while no effect was observed for Pt/SiO{sub 2}. The inhibiting effect of water was reversible and is attributed to competitive adsorption with the reactants. In sum, this study has shown that a variety of base metal catalysts are very active for NO oxidation. However, all of the catalysts studied are strongly deactivated in the presence of 2800 ppm SO{sub 2} at typical flue gas temperatures; consequently improving catalyst resistance to SO{sub x} will be a pre-requisite if the fast SCR concept is to be applied to coal-fired flue gas conditions.
Download or read book Development and Characterization of Mixed Oxide Catalysts for the Selective Catlytic Reduction of Nitric Oxide from Stationary Sources Using Amonnia written by and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Seven first row transition metals were deposited on various commercial TiO2, SiO2, and Al2 O3 supports to create mono- and bimetallic catalysts that were compared in the selective catalytic reduction of nitric oxide using ammonia at low temperatures ranging from 373-523 K. The catalyst with the highest activity both in the absence and presence of water in the feed was 20 wt.% Mn/Hombikat TiO2 synthesized from a nitrate precursor and calcined below 673 K. Under those conditions, it was capable of achieving 100% NO conversion at 393 K. Numerous surface characterization techniques were used to identify the surface properties that result in highly active and selective low temperature SCR catalysts. The deposition of manganese as MnO2, the ease of reducibility of the metal oxide, and the symmetric deformation of ammonia coordinated to Lewis acid sites at 1167 cm−1, were all found to be important for good catalytic performance. No synergistic effects were observed from combinations of the three most active transition metals. However, MnO x -NiO/TiO2 had an extended lifetime relative to MnO x /TiO2 in feeds containing SO2 . The extensive data collected from in-situ FTIR experiments in the presence of NO and NH 3 were used to propose a reaction mechanism for MnO x /TiO2 that begins with the coordination of NH3 over Mn4 species and proceeds through the formation of bridged nitrates. A combination of potentiometric titrations and UV/Vis spectroscopy were used to quantify the reduction of V5 to V4 after the addition of oxalic acid as the solution is aged. After approximately four hours, the aging vanadium oxalate solution reaches steady state, and the final distribution of the vanadium present is 89% V+4 and 11% V+5 . TiO2 supported monolayer catalysts synthesized from the aged (V+4) vanadium oxalate solution consistently outperformed catalysts made from freshly prepared (V+5) vanadium oxalate solutions. Surface characterization revealed that surface acid sites increase in strength and vanadia reduces more easily in catalysts synthesized from aged vanadium oxalate solutions, which enhances reaction mechanism depends upon acid sites and redox operation.
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 Metal Oxide Catalysts for Green Applications written by Tiberiu Popa and published by . This book was released on 2009 with total page 237 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cobalt oxide compounds are effective in decomposing N2O. A series of supported cobalt oxide catalysts with different amounts of cobalt oxide were synthesized by incipient wetness impregnation of gamma-alumina and by coprecipitation with precursors of cerium oxide. Each of the series of alkali metals (lithium, sodium, potassium, rubidium, and cesium) were added to each of the catalysts of varying cobalt oxide content to examine the promotion effect of these metals. The catalysts were characterized by surface area analysis, temperature programmed reduction, X-ray Diffraction, and UV-visible spectroscopy. Catalytic activity was investigated for the decomposition of both NO and N2O. The ceria-supported catalysts were significantly more active than the alumina-supported ones. With the same amount of cobalt, the ceria-supported catalysts produced equal reaction rates at around 200 K lower temperatures than the alumina-supported catalysts. All catalysts showed good activity for direct N2O decomposition over a temperature range of 573 K to 973 K. At 873 K, the reaction rate for alumina supported catalysts had values depending on cobalt loading between 1.4 and 1.7 x 10 -7 mol/(s g catalyst), while at the same temperature for ceria supported catalysts the values are 3.3 x 10 -7 mol/(s g catalyst). None of the catalysts maintained activity with NO as reactant, presumably forming surface nitrates or nitrites stoichiometrically without any catalytic turnover. The best alumina supported catalysts contained no alkali. Small amounts (0.01-0.05 atom %) of potassium or rubidium decreased the rate of N2O decomposition. The Water Gas Shift (WGS) project has as a goal to develop an integrated system to produce high purity hydrogen and generating CO2 at the purity required by its use in industry or needed for sequestration. As part of the present work, the production of an improved monolithic WGS catalyst that provides efficient conversion of CO and structural support for a stacked assembly of membranes was studied. This can be subdivided in two major parts: (1) The synthesis of more active catalysts having good compatibility with the monolithic support. The catalysts were prepared by adding alumina or ceria in the iron oxide based WGS catalyst; (2) The production and use of ceramic supports for the water gas shift catalysts; Alumina (Al2O3) was added as a component of conventional High Temperature. Addition of between 10 and 20 wt% alumina increased the catalyst activity and thermal stability, with approximately 15 wt% alumina addition being optimum as its reaction rate (normalized per mass) was 74% higher than the reference catalyst. The effect of alumina addition was greater than the surface area increase alone, which suggests that alumina increases the activity of the iron oxide domains, likely through an increase in reducibility, as shown by the TPR results. A series of high temperature water gas shift catalysts containing iron, chromia, and copper oxides were prepared with small amounts of added ceria in the system Fe-Cr-Cu-Ce-O. The catalysts were prepared by coprecipitation and compared with a reference catalyst containing 88 wt% FeOx, 8 wt% Cr2O3, and 4 wt% CuO. Unlike the other catalysts studied, the catalysts containing more than 85 wt% ceria do not exhibit the typical logarithmic decay curve in rate with time under reaction conditions, but instead show a minimum followed by an increased rate. This behavior, in addition to observations of the catalyst morphology from the SEM images, suggests that iron oxide-chromia is deposited on the surface of ceria and the magnetite-ceria interface is important for catalyst performance. Mullite porous ceramic disks were prepared by impregnation of foam rubber (to provide porosity) with a suspension containing kaolin and alumina and calcined at temperatures ranging between 1300 and 1400°C. The catalyst deposited on ceramic showed stability to oxygen and atmospheric humidity when exposed to air during handling between tests, losing only 17% of the activity it displayed at the end of the first test. A cordierite honeycomb type ceramic monolith was also impregnated. The monoliths are commercially available and provide better flow hydrodynamics for the reaction.
Download or read book The Synthesis of CuyMnzAl1 zOx Mixed Oxide as a Low temperature NH3 SCR Catalyst with Enhanced Catalytic Performance written by and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Pillared Clays and Related Catalysts written by Antonio Gil and published by Springer Science & Business Media. This book was released on 2010-08-28 with total page 531 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since the first works introducing the aluminum intercalated clay family in the early 1970s, interest in the synthesis of pillared interlayered clays has increased tremendously, especially research into the properties and applications of new synthesis methods. The need for solids that could be used as cracking catalysts with larger pores than zeolitic materials has spurred the synthesis of new porous materials from clays. Pillared Clays and Related Catalysts reviews the properties and applications of pillared clays and other layered materials used as catalysts, focusing on: the acidity of pillared clays and the effect it has on catalytic performance the use of pillared clays as supports for catalytically active phases, and the use of the resulting solids in environmentally friendly reactions the applications of the selective reduction of NOx the comparison between the reactions of pillared clays and anionic clays.
Download or read book Advances and Technology Development in Greenhouse Gases Emission Capture and Conversion written by Mohammad Reza Rahimpour and published by Elsevier. This book was released on 2024-07-19 with total page 446 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advances and Technology Development in Greenhouse Gases: Emission, Capture and Conversion is a comprehensive seven-volume set of books that discusses the composition and properties of greenhouse gases, and introduces different sources of greenhouse gases emission and the relation between greenhouse gases and global warming. The comprehensive and detailed presentation of common technologies as well as novel research related to all aspects of greenhouse gases makes this work an indispensable encyclopedic resource for researchers in academia and industry.Volume 6 titled Methane, Nitrox Oxide, and Ozone Conversion and Applications studies the applications of any greenhouse gases (GHGs) other than carbon dioxide. This book reviews the applications of methane, nitrox oxide, and ozone. It investigates any valuable product fabricated with the inclusion of methane, nitrox oxide, and ozone. The book also reviews recent advances, the largest operating plants and pilots for methane conversion, the economic assessments and cost analysis, and environmental impacts and challenges that are faced when developing these processes Introduces applications and chemicals produced from methane Describes nitrous oxide conversion and applications Discusses about various applications of ozone
Download or read book Low Carbon Stabilization and Solidification of Hazardous Wastes written by Daniel C.W. Tsang and published by Elsevier. This book was released on 2021-09-24 with total page 592 pages. Available in PDF, EPUB and Kindle. Book excerpt: Low Carbon Stabilization and Solidification of Hazardous Wastes details sustainable and low-carbon treatments for addressing environmental pollution problems, critically reviewing low-carbon stabilization/solidification technologies. This book presents the latest state-of-the-art knowledge of low-carbon stabilization/solidification technologies to provide cost-effective sustainable solutions for real-life environmental problems related to hazardous wastes including contaminated sediments. As stabilization/solidification is one of the most widely used waste remediation methods for its versatility, fast implementation and final treatment of hazardous waste treatment, it is imperative that those working in this field follow the most recent developments. Low Carbon Stabilization and Solidification of Hazardous Wastes is a necessary read for academics, postgraduates, researchers and engineers in the field of environmental science and engineering, waste management, and soil science, who need to keep up to date with the most recent advances in low-carbon technologies. This audience will develop a better understanding of these low-carbon mechanisms and advanced characterization technologies, fostering the future development of low-carbon technologies and the actualization of green and sustainable remediation. Focuses on stabilization/solidification for environmental remediation, as one of the most widely used environmental remediation technologies in field-scale applications Details the most advanced and up-to-date low-carbon sustainable technologies necessary to guide future research and sustainable development Provides comprehensive coverage of low-carbon solutions for treating a variety of hazardous wastes as well as contaminated soil and sediment
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.
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 Environmental Catalysis written by John N. Armor and published by American Chemical Society. This book was released on 1994 with total page 464 pages. Available in PDF, EPUB and Kindle. Book excerpt: The first comprehensive volume on the major aspects of environmental catalysis. Focuses on NO x removal, mobile engine emission controls, power plant emissions, control of volatile organic compounds, SO x emissions, and waste minimization. Overview chapters introduce each section and provide added perspective and coverage. Includes comprehensive technical reports on automotive and diesel emission control catalysis, NO x removal, and removal of chlorinated hydrocarbons from various process streams.
