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 2004 with total page 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. Evaluation of these sorbents as catalysts for the selective reduction of NO[sub x] gave promising results with methane. Since the replacement of ammonia by methane is commercially very attractive, in this project, the effect of promoters on the activity and selectivity of copper oxide/cerium oxide-based catalysts and the reaction mechanism for the SCR with methane was investigated. Unpromoted and promoted catalysts were investigated for their SCR activity with methane in a microreactor setup and also, by the temperature-programmed desorption (TPD) technique. The results from the SCR experiments indicated that manganese is a more effective promoter than the other metals (Rh, Li, K, Na, Zn, and Sn) for the supported copper oxide-ceria catalysts under study. The effectiveness of the promoter increased with the increase in Ce/Cu ratio. Among the catalysts tested, the Cu1Ce3 catalyst promoted with 1 weight% Mn was found to be the best catalyst for the SCR of NO with methane. This catalyst was subjected to long-term testing at the facilities of our industrial partner TDA Research. TDA report indicated that the performance of this catalyst did not deteriorate during 100 hours of operation and the activity and selectivity of the catalyst was not affected by the presence of SO[sub 2]. The conversions obtained by TDA were significantly lower than those obtained at Hampton University due to the transport limitations on the reaction rate in the TDA reactor, in which 1/8th inch pellets were used while the Hampton University reactor contained 250-425-[micro]m catalyst particles. The selected catalyst was also tested at the TDA facilities with high-sulfur heavy oil as the reducing agent. Depending on the heavy oil flow rate, up to 100% NO conversions were obtained. The temperature programmed desorption studies a strong interaction between manganese and cerium. Presence of manganese not only enhanced the reduction rate of NO by methane, but also significantly improved the N[sub 2] selectivity. To increase the activity of the Mn-promoted catalyst, the manganese content of the catalyst need to be optimized and different methods of catalyst preparation and different reactor types need to be investigated to lower the transport limitations in the reactor.
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 New Heterogeneous Catalysts for the Selective Reduction of NOx Under Lean Conditions Final Report written by and published by . This book was released on 2004 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: The original goal of this program was the identification and design of new noble-metal-based catalysts for the selective catalytic reduction of nitric oxide by hydrocarbons under excess oxygen (i.e., ''lean'') conditions (HC-SCR). Work conducted in the first funding cycle of this award (i.e., 1997-2000) was successful in allowing us to develop an understanding of the fundamental surface chemistry taking place during the adsorption and reaction of nitrogen oxides and propylene on the surface of supported noble metal catalysts. Both experimental results collected in our own group as well as molecular simulation results published by Professor Neurock suggested that in order to improve the performance of the Pt catalysts--in terms of the nitrogen selectivity and the temperature window of operation-- it was necessary to introduce a second metal. However, synthesizing such catalysts with the metals of interest (i.e., Pt-Au, Pt-Ru, Pt-Rh, etc.) with some degree of control of the structure and composition of the resulting supported metal particles is in itself a research challenge. Consequently, the bulk of our efforts during the second funding cycle of this award (covered by this report) was shifted to the use of organometallic cluster precursors for the synthesis on novel bimetallic catalysts. During this time we have also continued to maintain an interest in NOx abatement, but have redirected our efforts from the HC-SCR process to the more promising from a commercial standpoint NOx Storage Reduction (NSR) approach.
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 Selective Catalytic Reduction of Nitrogen Oxides by Oxygenated Hydrocarbons written by Stephen Grenville Masters and published by . This book was released on 1999 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 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 An Investigation of the Selective Catalytic Reduction of Nitrogen Monoxide by Hydrocarbons Under Oxidising Conditions written by Paul James Millington and published by . This book was released on 1995 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Changing Landscape of Hydrocarbon Feedstocks for Chemical Production written by National Academies of Sciences, Engineering, and Medicine and published by National Academies Press. This book was released on 2016-12-10 with total page 137 pages. Available in PDF, EPUB and Kindle. Book excerpt: A decade ago, the U.S. chemical industry was in decline. Of the more than 40 chemical manufacturing plants being built worldwide in the mid-2000s with more than $1 billion in capitalization, none were under construction in the United States. Today, as a result of abundant domestic supplies of affordable natural gas and natural gas liquids resulting from the dramatic rise in shale gas production, the U.S. chemical industry has gone from the world's highest-cost producer in 2005 to among the lowest-cost producers today. The low cost and increased supply of natural gas and natural gas liquids provides an opportunity to discover and develop new catalysts and processes to enable the direct conversion of natural gas and natural gas liquids into value-added chemicals with a lower carbon footprint. The economic implications of developing advanced technologies to utilize and process natural gas and natural gas liquids for chemical production could be significant, as commodity, intermediate, and fine chemicals represent a higher-economic-value use of shale gas compared with its use as a fuel. To better understand the opportunities for catalysis research in an era of shifting feedstocks for chemical production and to identify the gaps in the current research portfolio, the National Academies of Sciences, Engineering, and Medicine conducted an interactive, multidisciplinary workshop in March 2016. The goal of this workshop was to identify advances in catalysis that can enable the United States to fully realize the potential of the shale gas revolution for the U.S. chemical industry and, as a result, to help target the efforts of U.S. researchers and funding agencies on those areas of science and technology development that are most critical to achieving these advances. This publication summarizes the presentations and discussions from the workshop.
Download or read book Development of Catalyst for Selective Reduction of NOx and Oxidation of CO and Hydrocarbons written by and published by . This book was released on 1997 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Presently available technologies for control of engine NOx are not applicable in diesel engines and microns research projects are in progress in both the U.S. and Japan to find a practical method of catalytically reducing NOx in diesel exhaust. This report describes are laboratory scale testing of two possible methods of doing this. Tests were done with gas mixtures which simulated diesel exhaust. Of the two NOx control methods tested, one was found unpromising while the other gave promising results when propane was used as the NOx reducing agent. Since, however, the results with diesel fuel as the reducing agent were not promising, further development did not seem justified. It appears likely than the need to used diesel fuel is the NOx reductant in any practical system will be an issue in the other research projects now ongoing.
Download or read book Development of a Water Resistant NOx Reduction Catalyst written by Christopher M. Rodenbush and published by . This book was released on 2003 with total page 228 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Development of Pt MCM 41 Catalysts for Selective Catalytic Reduction of Lean NO x Using Hydrocarbon written by Shoucang Shen and published by . This book was released on 2001 with total page 446 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Catalysis Looks to the Future written by National Research Council and published by National Academies Press. This book was released on 1992-02-01 with total page 97 pages. Available in PDF, EPUB and Kindle. Book excerpt: The impact of catalysis on the nation's economy is evidenced by the fact that catalytic technologies generate U.S. sales in excess of $400 billion per year and a net positive balance of trade of $16 billion annually. This book outlines recent accomplishments in the science and technology of catalysis and summarizes important likely challenges and opportunities on the near horizon. It also presents recommendations for investment of financial and human resources by industry, academe, national laboratories, and relevant federal agencies if the nation is to maintain continuing leadership in this fieldâ€"one that is critical to the chemical and petroleum processing industries, essential for energy-efficient means for environmental protection, and vital for the production of a broad range of pharmaceuticals.
Download or read book The Chemistry of Pincer Compounds written by David Morales-Morales and published by Elsevier. This book was released on 2011-08-11 with total page 467 pages. Available in PDF, EPUB and Kindle. Book excerpt: Pincer complexes are formed by the binding of a chemical structure to a metal atom with at least one carbon-metal bond. Usually the metal atom has three bonds to a chemical backbone, enclosing the atom like a pincer. The resulting structure protects the metal atom and gives it unique properties.The last decade has witnessed the continuous growth in the development of pincer complexes. These species have passed from being curiosity compounds to chemical chameleons able to perform a wide variety of applications. Their unique metal bound structures provide some of the most active catalysts yet known for organic transformations involving the activation of bonds. The Chemistry of Pincer Compounds details use of pincer compounds including homogeneous catalysis, enantioselective organic transformations, the activation of strong bonds, the biological importance of pincer compounds as potential therapeutic or pharmaceutical agents, dendrimeric and supported materials. * Describes the chemistry and applications of this important class of organometallic and coordination compounds* Covers the areas in which pincer complexes have had an impact* Includes information on more recent and interesting pincer compounds not just those that are well-known
Download or read book Selective Catalytic Reduction of NOx by Hydrocarbons Over Fe ZSM5 Prepared by Sublimation of FeCl3 written by Andrea Antonio Battiston and published by . This book was released on 2003 with total page 191 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book MECHANISTIC STUDIES AND DESIGN OF HIGHLY ACTIVE CUPRATE CATALYSTS FOR THE DIRECT DECOMPOSITION AND SELECTIVE REDUCTION OF NITRIC OXIDE AND HYDROCARBONS TO NITROGEN FOR ABATEMENT OF STACK EMISSIONS written by and published by . This book was released on 1998 with total page 41 pages. Available in PDF, EPUB and Kindle. Book excerpt: A flow trough type catalytic reactor system was adequately modified for NO related catalytic and adsorption measurements, including the on-line connection of a digital chemiluminescent NO-NO(subscript x) analyzer to the reactor outlet system. Moreover, we have largely completed the installation of an FTIR coupled catalytic system containing a HTEC cell for high temperature DRIFT studies. Three different barium cuprate samples, Ba2CuO3, BaCuO2, and Ba2Cu3O5 were synthesized and characterized by powder XRD for catalytic tests. Prior to catalytic studies over these cuprates, a new, liquid indium based supported molten metal catalyst (In-SMMC) was tested in the reduction of NO by various reductants. In the presence of excess O2 and H2O, the In-SMMC proved to be more active for the selective catalytic reduction (SCR) of NO to N2 by ethanol than most other catalysts. Using C1-C3 alcohols as reductants, self sustained periodic oscillations observed in the NO(subscript x) concentrations of reactor effluents indicated the first time that radical intermediates can be involved in the SCR of NO by alcohols. Further, In-SMMC is the only effective and water tolerant SCR catalyst reported thus far which contains SiO2 support. Thus, this novel catalyst opens up a promising new alternative for developing an effective and durable catalyst for NO(subscript x) abatement in stack emission.
Download or read book Selective Catalytic Reduction SCR of Nitric Oxide NO with Ammonia Over Vanadia based and Pillared Interlayer Clay based Catalysts written by Hyuk Jin Oh and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The selective catalytic reduction (SCR) of nitric oxide (NO) with ammonia over vanadia-based (V2O5-WO3/TiO2) and pillared interlayer clay-based (V2O5/Ti-PILC) monolithic honeycomb catalysts using a laboratory laminar-flow reactor was investigated. The experiments used a number of gas compositions to simulate different combustion gases. A Fourier transform infrared (FTIR) spectrometer was used to determine the concentrations of the product species. The major products were nitric oxide (NO), ammonia (NH3), nitrous oxide (N2O), and nitrogen dioxide (NO2). The aim was to delineate the effect of various parameters including reaction temperature, oxygen concentration, NH3-to-NO ratio, space velocity, heating area, catalyst arrangement, and vanadium coating on the removal of nitric oxide. The investigation showed that the change of the parameters significantly affected the removals of NO and NH3 species, the residual NH3 concentration (or NH3 slip), the temperature of the maximum NO reduction, and the temperature of complete NH3 conversion. The reaction temperature was increased from the ambient temperature (25°C) to 450°C. For both catalysts, high NO and NH3 removals were obtained in the presence of a small amount of oxygen, but no significant influence was observed from 0.1 to 3.0% O2. An increase in NH3-to-NO ratio increased NO reduction but decreased NH3 conversions. For V2O5-WO3/TiO2, the decrease of space velocity increased NO and NH3 removals and broadened the active temperature window (based on NO> 88% and NH3> 87%) about 50°C. An increase in heating area decreased the reaction temperature of the maximum NO reduction from 350 to 300 ʻC, and caused the active reaction temperature window (between 250 and 400 ʻC) to shift toward 50 ʻC lower reaction temperatures (between 200 and 350°C). The change of catalyst arrangements resulted slight improvement for NO and NH3 removals, therefore, the change might contribute to more gas removals. The catalyst with extra vanadium coating showed higher NO reductions and NH3 conversions than the catalyst without the extra vanadium coating.
