Download or read book Transient Catalytic Combustion on a Flat Plate written by Ahmad Fakheri and published by . This book was released on 1982 with total page 146 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Catalytic Combustion in a Transient High Presssure Facility written by David Robert James Baxter and published by . This book was released on 1985 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Two Dimensional Transient Modeling of Catalytic Combustion written by Neeraj Sinha and published by . This book was released on 1982 with total page 292 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Catalytic Combustion in a Transient High Pressure Facility written by David Robert James Baxter and published by . This book was released on 1985 with total page 188 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Transient Catalytic Combustion written by D. A. Santavicca and published by . This book was released on 1986 with total page 29 pages. Available in PDF, EPUB and Kindle. Book excerpt: Results of an experimental study of the catalytic ignition of lean propane-air mixtures on platinum in a stacked-plate catalytic combustor are presented. The effects of inlet temperature, equivalence ratio and gas velocity on the ignition transient were investigated. The ignition process was characterized in terms of the substrate axial temperature profile and the exhaust gas CO and CO2 concentrations measured as a function of time after the fuel was turned on. Ignition was always found to occur first near the leading edge of the catalyst as indicated by the more rapid heat-up of the front end of the catalyst. The downstream end of the catalyst heated up more slowly and was strongly dependent on convective heat transfer from the front of the catalyst. Increased inlet temperature, equivalence ratio and velocity were all found to shorten the ignition transient and to lead to increased steady state peak substrate temperatures. increased velocity also caused the peak substrate temperature to move further toward the back of the catalyst. For the conditions studied, the initial ignition rate was found to be surface reaction rate controlled at higher velocities (above 2 m/s) but at lower velocities (below 2 m/s) the initial ignition rate was found to depend both on the surface reaction rate and the mass transport rate. The transient ignition measurements also clearly revealed the fact that complete conversion can be achieved by substrate temperatures which are several hundred degrees below steady state. Keywords: Catalytic combustion, Catalytic ignition, and Premixed turbulent combustion.
Download or read book Introduction to Catalytic Combustion written by R.E. Hayes and published by Routledge. This book was released on 2021-10-25 with total page 690 pages. Available in PDF, EPUB and Kindle. Book excerpt: In a clear and concise manner, this book explains how to apply concepts in chemical reaction engineering and transport phenomena to the design of catalytic combustion systems. Although there are many textbooks on the subject of chemical reaction engineering, catalytic combustion is mentioned either only briefly or not at all. The authors have chosen three examples where catalytic combustion is utilized as a primary combustion process and natural gas is used as a fuel - stationary gas turbines, process fluid heaters, and radiant heaters; these cover much of the area where research is currently most active. In each of these there are clear environmental benefits to be gained illustrating catalytic combustion as a "cleaner primary combustion process" . The dominant heat transfer processes in each of the applications are different, as are the support systems, flow geometrics and operating conditions.
Download or read book A Global Reaction Mechanism for Transient Simulations of Three way Catalytic Converters written by Raoul Holder and published by Cuvillier Verlag. This book was released on 2008 with total page 147 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book High Temperature Catalytically Assisted Combustion written by F. V. Bracco and published by . This book was released on 1983 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: Results of research on a two dimensional, transient catalytic combustion model and on a high temperature perovskite catalyst are presented. A recently developed two dimensional, transient model has been used to study the ignition of carbon monoxide/air mixtures in a platinum coated catalytic honeycomb. Comparisons between calculated and measured steady state substrate temperature profiles and exhaust gas compositions show good agreement. A platinum doped perovskite catalyst has been proposed which will exhibit low temperature light off and high temperature stability. Preliminary tests using a perovskite powder with one percent by weight platinium are encouraging, showing very little change in surface activity when used with propane fuel. Variations in catalytic activity from sample to sample have also been found and after extensive testing the cause of these variations have not been identified. However, preliminary tests using Fourier transform infrared photoacoustic spectroscopy do indicate differences in the various catalyst samples that may be related to the difference in catalytic activity. The use of bench top oven and differential scanning calorimetry techniques for screening catalysts in terms of relative activity and aging characteristics has also been demonstrated. Originator-supplied keywords include: Catalytic combustion, and Perovskite catalysts.
Download or read book Studies of Partial Oxidation and Combustion Over Heterogeneous Catalysts by Transient Experiments written by Andreas Hinz and published by . This book was released on 2001 with total page 61 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Effect of Surface Reactions in Catalytic Combustion written by D. A. Santavicca and published by . This book was released on 1985 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: Experiments were conducted in order to better understand the role of catalytic surface reactions in determining the ignition characteristics of practical catalytic combustors. Measurements of hydrocarbon concentrations, carbon monoxide and carbon dioxide concentrations, hydroxyl radical concentrations and gas temperature were made at the exit of a platinum coated, stacked plated, catalytic combustor during the ignition of lean propane-air mixtures. The substrate temperature profile was also measured during the ignition transient. In these experiments, ignition was initiated by suddenly turning on the fuel and the time to reach steady state was of the order of ten minutes. The gas phase reactions, which were clearly observable from these measurements, showed no pronounced effect due to the catalytic surface reactions, except possibly the absence of an hydroxyl radical overshoot. The transient ignition measurements were found to be valuable in understanding the steady state performance characteristics.
Download or read book Microscale Combustion and Power Generation written by Christopher Cadou and published by Momentum Press. This book was released on 2014-12-26 with total page 720 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent advances in microfabrication technologies have enabled the development of entirely new classes of small-scale devices with applications in fields ranging from biomedicine, to wireless communication and computing, to reconnaissance, and to augmentation of human function. In many cases, however, what these devices can actually accomplish is limited by the low energy density of their energy storage and conversion systems. This breakthrough book brings together in one place the information necessary to develop the high energy density combustion-based power sources that will enable many of these devices to realize their full potential. Engineers and scientists working in energy-related fields will find: • An overview of the fundamental physics and phenomena of microscale combustion; • Presentations of the latest modeling and simulation techniques for gasphase and catalytic micro-reactors; • The latest results from experiments in small-scale liquid film, microtube, and porous combustors, micro-thrusters, and micro heat engines; • An assessment of the additional research necessary to develop compact and high energy density energy conversion systems that are truly practical.
Download or read book Reaction Kinetics and the Development and Operation of Catalytic Processes written by G.F. Froment and published by Elsevier. This book was released on 2001-04-03 with total page 663 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reaction Kinetics and the Development and Operation of Catalytic Processes is a trendsetter. The Keynote Lectures have been authored by top scientists and cover a broad range of topics like fundamental aspects of surface chemistry, in particular dynamics and spillover, the modeling of reaction mechanisms, with special focus on the importance of transient experimentation and the application of kinetics in reactor design. Fundamental and applied kinetic studies are well represented. More than half of these deal with transient kinetics, a new trend made possible by recent sophisticated experimental equipment and the awareness that transient experimentation provides more information and insight into the microphenomena occurring on the catalyst surface than steady state techniques. The trend is not limited to purely kinetic studies since the great majority of the papers dealing with reactors also focus on transients and even deliberate transient operation. It is to be expected that this trend will continue and amplify as the community becomes more aware of the predictive potential of fundamental kinetics when combined with detailed realistic modeling of the reactor operation.
Download or read book Numerical Investigation of Wall Heat Conduction Effects in Catalytic Combustion Systems written by Michael Grimm and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Catalytic converters are used in a variety of applications ranging from low-temperature combustion for gas turbine applications to the removal of pollutants from engine exhaust flow. Catalytic converters currently used in industry consist of a ceramic monolithic plug. This monolithic plug has a honeycomb-like structure, and is comprised of many small cylindrical channels (tubes), the inner surfaces of which are covered with a reactive catalyst. Determining the effect of the thermal conductivity of the monolith ceramic material on the ignition, flame stability, and steady state combustion will provide a scientific foundation with regard to the selection of materials for the construction of catalytic monoliths. This effect is investigated in this study through numerical simulations. Two commonly used materials are compared: cordierite, a ceramic with a low thermal conductivity, and silicon carbide, a ceramic with a high thermal conductivity. Another issue that is critical to the design of a catalytic converter is the length of the monolith plug. The optimum length of a monolith tube is one that completely converts the incoming flow while utilizing the entire length of the catalytic coating. In practice, the length is adjusted by stacking monolith plugs end-to-end, though it is unclear how different the end-to-end plugs are when compared to a single continuous tube of the same length. This study numerically investigates the effects of this practice, with the goal to determine if a tube of length 2L exhibits the same behavior as two identical tube sections placed end-to-end, each of length L. The commercial CFD software CFD-ACE+TM was utilized to investigate the afore-stated issues. The inlet flow rates of the methane-air mixture and the fuel equivalence ratio (or fuel-air ratio) were treated as parameters. Only lean and stoichiometric mixtures were considered because in practice catalytic combustion is not performed with rich mixtures. Catalytic combustion of a methane-air mixture on a platinum catalyst was used as the candidate system because the chemistry of this system is well documented. The models were set up and tested in an order of increasing complexity to ensure steady progress in the research. Beginning with simple flow and heat transfer, the model was extended to include a single step combustion reaction, and finally a detailed reaction mechanism consisting of 24 surface reactions between 19 species. Both steady-state and transient simulations were conducted. The results show that thermal conductivity of the ceramic monolith has a large effect on ignition, flame stability, and steady state combustion. The ceramic material with a high thermal conductivity value, namely silicon carbide, produces a stable flame over a much wider range of inlet flow rates than the ceramic material with a low thermal conductivity value, namely cordierite. Over their respective ranges of ignition, for both silicon carbide and cordierite, the maximum temperature of the monolith tube is more or less the same, indicating that there is no effect of thermal conductivity on the maximum temperature. Therefore, a case can be made for using silicon carbide instead of cordierite to create catalytic monoliths capable of handling a wider variety of inlet flow rates. The results also show that the ignition and blowout limits vary significantly between split and continuous tubes at high inlet flow speeds when the monolith tube walls are constructed from materials with high thermal conductivity; in this case, silicon carbide. For high inlet flow speeds there are significant differences between split and continuous tubes for the high thermal conductivity material. For monolith tubes constructed from materials with low thermal conductivity, such as the case of cordierite, there are no significant differences between split and continuous tubes over the entire flammability range. Additionally, for high thermal conductivity materials with low inlet flow speeds and low thermal conductivity materials for all inlet flow speeds over the range of ignition, the fuel conversion percentage does not significantly change and therefore, appears to be independent of inlet flow speed. These results imply that axial heat conduction, or lack thereof due to thermal contact resistance from an air-gap between the end-to-end monolith plugs, through the walls of the monolith results in thermal non-equilibrium between the solid and fluid phase, and subsequently affects ignition and flame stability in catalytic combustion.
Download or read book Catalysis written by James J Spivey and published by Royal Society of Chemistry. This book was released on 2007-10-31 with total page 354 pages. Available in PDF, EPUB and Kindle. Book excerpt: There is an increasing challenge for chemical industry and research institutions to find cost-efficient and environmentally sound methods of converting natural resources into fuels chemicals and energy. Catalysts are essential to these processes and the Catalysis Specialist Periodical Report series serves to highlight major developments in this area. This series provides systematic and detailed reviews of topics of interest to scientists and engineers in the catalysis field. The coverage includes all major areas of heterogeneous and homogeneous catalysis and also specific applications of catalysis such as NOx control kinetics and experimental techniques such as microcalorimetry. Each chapter is compiled by recognised experts within their specialist fields and provides a summary of the current literature. This series will be of interest to all those in academia and industry who need an up-to-date critical analysis and summary of catalysis research and applications. Catalysis will be of interest to anyone working in academia and industry that needs an up-to-date critical analysis and summary of catalysis research and applications. Specialist Periodical Reports provide systematic and detailed review coverage in major areas of chemical research. Compiled by teams of leading experts in their specialist fields, this series is designed to help the chemistry community keep current with the latest developments in their field. Each volume in the series is published either annually or biennially and is a superb reference point for researchers. www.rsc.org/spr
Download or read book Synthesis Gas Combustion written by Tim Lieuwen and published by CRC Press. This book was released on 2009-09-16 with total page 388 pages. Available in PDF, EPUB and Kindle. Book excerpt: Coal, still used to generate more than half of the electric power in the U.S., will likely be part of any future global energy plan. But this finite resource is also responsible for 80 percent of the CO2 emissions from power production, and its continued use will require improved processing techniques that are less damaging to the environment and l
Download or read book Joint Meeting of the U S Sections of the Combustion Institute Western States Central States Eastern States written by and published by . This book was released on 2005 with total page 138 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Acceleration of the Transient Response of Automotive Catalytic Converters written by Anthony Montevirgen and published by . This book was released on 2008 with total page 164 pages. Available in PDF, EPUB and Kindle. Book excerpt:
