Download or read book Development and validation of a chemical kinetic combustion model for pulverised coal combustion written by 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 Fundamentals of the Physical Chemistry of Pulverized Coal Combustion written by L Lahaye and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 505 pages. Available in PDF, EPUB and Kindle. Book excerpt: The study of coal for the production of energy is certainly not a new area of research. Many research works were carried out to improve the efficiency of industrial and domestic facilities. In the sixties, however, because of the availability and low cost of petroleum, coal consumption decreased and the research effort in this area was minimum. Meanwhile, the situation has totally changed. Considering the reserves of oil and the instability ofregions where they are located, it is becoming absolutely necessary to develop other sources of energy.The major alternative to oil appears to be coal, at least for the near future. Indeed, the reserves known today represent several centuries of energy consumption.!t is therefore becoming urgent to develop efficient and non polluting technologies to produce energy from coal. The main possibilities are : · liquefaction · gasification · directed combustion. Research and development efforts on liquefaction have been considerably reduced because of high cost of technologies involved and poor prospects for the next two decades. Research works on gasification are progressing; it is a promising approach. However, direct combustion either in pulverized coal furnaces or in fluidized beds is the more promising way of expanding rapidly the utilization of coal. These techniques are already used in some facilities but many environmental problems remain, slowing down their development.
Download or read book Detailed and Reduced Kinetic Mechanisms in Low Emission Combustion Processes written by Sylvie Honnet and published by Cuvillier Verlag. This book was released on 2007-10-11 with total page 148 pages. Available in PDF, EPUB and Kindle. Book excerpt: The aim of this work is the application of the Representative Interactive Flamelet (RIF) model with detailed and reduced kinetics to describe the combustion processes with low-emission. Chemical kinetic reaction mechanisms are developed. Regarding the application of these mechanisms in the numerical simulation of combustion processes, the description of the formation of nitrous oxide is particularly taken into account. After the introduction in the topic, chapter 2 presents the conservation equations and the description of the turbulent flow and mixing field. The flamelet model and the RIF-concept are described: the chemical reaction kinetics is separately considered from the flow dynamics. This is possible due to the assumption of the existence of a very thin flame layer, in which the chemical processes take place. This flame layer, also considered as laminar in turbulent flows, is called flamelet. The calculation of the ignition, heat release and formation of nitrogen oxide with detailed kinetics is then possible. In chapter 3, a model for the calculation of three-dimensional combustion processes is presented. It is based on the flamelet model. To describe the formation of nitrous oxide, the consideration of the combustion as an unsteady process is very important. This is possible thanks to the use of unsteady flamelets. The flamelets are calculated interactive with the flow solver, each representative for a pathway of particle through the combustion chamber. The statistical way of fluid particle through the combustion chamber is described by the eulerian transport equations. In chapter 4, a chemical reaction mechanism is developed and validated with comparison with experimental results. Special attention is paid to the methane mechanism with consideration of nitrous oxide formation. This mechanism is reduced with steady-state assumptions. Furthermore, a pyrolysis and burnout model are presented, which are used for the simulation of the coal combustion in chapter 5. In chapter 5, simulation results for two different configurations are compared to experimental data. In the MILD combustion chamber, the formation of nitrous oxide is investigated with the use of the detailed and reduced kinetics presented in chapter 4. The Eulerian Particle Flamelet model is completed and used for the simulation of the gaseous phase during the coal combustion. Based on the results, it is shown that the flamelet model, coupled with the detailed and the reduced kinetics, is able to model low-emission combustion processes.
Download or read book Pulverized Coal Combustion and Gasification written by L. Smoot and published by Springer Science & Business Media. This book was released on 2013-04-17 with total page 336 pages. Available in PDF, EPUB and Kindle. Book excerpt: viii and approaches could be adapted to other coal conversion and combustion problems, we have not considered combustion or gasification in fluidized or fixed beds or in situ processes. In addition, we have not considered other fossil-fuel combustion problems associated with oil shale, tar sands, etc., even though many aspects of pulverized-coal combustion would relate to these problems. For the case of pulverized-coal models, we have attempted to provide a detailed description of the model foundations. Parts I and II of this book emphasize general principles for describing reacting, turbulent or laminar, multiphase systems. General conservation equations are developed and summarized. The basis for computing thermochemical equilibrium in complex, heterogeneous mixtures is presented, together with techniques for rapid computation and reference to required input data. Rate processes are then discussed, including pertinent aspects of turbulence, chemical kinetics, radiative heat transfer, and gas-particle convective-diffusive interactions. Much of Part II deals with parameters and coefficients for describing these complex rate processes. This part of the book provides recommended values of coefficients and parameters for treating complex reacting flows. Parts I and II may well be suitable for use in an advanced course in reacting flows, and have been written partly with that in mind. Part III deals with more specific aspects of pulverized-coal characteristics and rate processes. Following a general description of coal structure and constitution, coal pyrolysis and char oxidation processes are considered.
Download or read book Kinetics of Coal Pyrolysis and Devolatilization written by and published by . This book was released on 1987 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of these experimental and modeling studies is to develop an improved understanding of the kinetics of coal devolatilization which is relevant to suspension firing of powdered coal. These fundamental kinetic studies address several topics related to pulverized coal combustion and include both homogeneous and heterogeneous reactions. The principal topics include: (1) the pyrolysis and devolatilization of coal; and (2) the formation of char. Research activities include small-scale experimentation, interpretation of experimental results in terms of mechanistic understanding and the development and validation of kinetic models of fundamental processes. This report consists of two contributions. The first is from MIT entitled Intra-Particle Heat Transfer Effects in Coal Pyrolysis''. While this modeling study bears some similarity to the Ohio State work, it is proposed as the starting point for a more complete model which will include other boundary conditions as well as mass transfer effects. The second contribution is a report from UTRC entitled Effect of Heat Transfer on Tar and Light Gases From Coal Pyrolysis''. This work documents some of the changes in the chemical composition of the products of pyrolysis when the mode or rate of heat transfer is varied. 28 refs., 17 figs., 3 tabs.
Download or read book Coal Combustion and Gasification written by L.Douglas Smoot and published by Springer Science & Business Media. This book was released on 2013-11-11 with total page 450 pages. Available in PDF, EPUB and Kindle. Book excerpt: The use of coal is required to help satisfy the world's energy needs. Yet coal is a difficult fossil fuel to consume efficiently and cleanly. We believe that its clean and efficient use can be increased through improved technology based on a thorough understanding of fundamental physical and chemical processes that occur during consumption. The principal objective of this book is to provide a current summary of this technology. The past technology for describing and analyzing coal furnaces and combus tors has relied largely on empirical inputs for the complex flow and chemical reactions that occur while more formally treating the heat-transfer effects. GrOWing concern over control of combustion-generated air pollutants revealed a lack of understanding of the relevant fundamental physical and chemical mechanisms. Recent technical advances in computer speed and storage capacity, and in numerical prediction of recirculating turbulent flows, two-phase flows, and flows with chemical reaction have opened new opportunities for describing and modeling such complex combustion systems in greater detail. We believe that most of the requisite component models to permit a more fundamental description of coal combustion processes are available. At the same time there is worldwide interest in the use of coal, and progress in modeling of coal reaction processes has been steady.
Download or read book Development of a Reduced Chemical kinetic Combustion Model for Practical Fuels written by Anton Zizin and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Pulverized Coal Combustion written by Stanley Singer and published by William Andrew. This book was released on 1984 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Coal Combustion written by Jerzy Tomeczek and published by . This book was released on 1994 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt: Explains the combustion phenomena of a single coal particle and of coal particles in pulverised flames and fluidised beds. The state of knowledge regarding the combustion mechanism, and the implications for combustion equipment design, are reviewed.
Download or read book Chemical Kinetics of Coal Combustion and Pollution Formation written by G. Domazetis and published by . This book was released on 1986 with total page 31 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Kinetic Model of Pulverised Coal Combustion for Computational Fluid Dynamics written by Dieter Förtsch and published by . This book was released on 2003 with total page 165 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Experimental Validation of Pulverized Coal Combustion written by Luke P. McLaughlin and published by . This book was released on 2019 with total page 75 pages. Available in PDF, EPUB and Kindle. Book excerpt: Pulverized coal particle combustion in an entrained flow burner with a co-flow pilot flame was examined experimentally with the intent of validating a recently developed coal combustion model to be used for developing advanced combustion strategies. In this work, experimental studies were performed and data were acquired for validation of the model under two conditions: an O2-rich environment in which coal combustion occurs, and an O2-deficient environment in which coal pyrolysis occurs. A carefully controlled coal particle size was achieved through a multi-step sample preparation procedure consisting of sieving and washing, and the impacts on combustion were assessed. Multiple validation targets for the numerical model were measured in combustion experiments, including temperature profiles of the particle-free entrainment gases, integrated narrowband light intensity profiles from the centerline of an entrained coal particle flow and integrated soot temperature and volume fraction-length factor profiles from the centerline of an entrained coal particle flow.
Download or read book NOx Modelling and Prediction written by Ruksana Moreea-Taha and published by . This book was released on 2000 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Statistical Kinetics for Pulverized Coal Combustion written by and published by . This book was released on 1996 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: Coal is a heterogeneous substance whose structure and properties are highly variable on the length scale of the particle sizes used in suspension-fired combustion systems. For certain applications the statistical variations among particles can play an important role. In this paper, three specialized, single-particle techniques are applied to quantify the variations in combustion reactivity and char particle density within pulverized char particle populations. Reactivity variations are investigated through captive particle imaging experiments and entrained flow reactor experiments employing single-particle optical diagnostics. Single-particle density variations are determined directly by a novel technique based on an electrodynamic microbalance equipped with an automated video imaging and image processing system. From these data, a coal-general statistical kinetic model is developed and validated against a large set of single-particle temperature measurements for ten coals of various rank burning in three different combustion environments. The model incorporates a single empirical parameter describing the heterogeneity in reactivity and can adequately describe the entire database using a single coal-independent value of this parameter. The use of the model is demonstrated in a series of numerical simulations of complete burnout process for size-classified and polydisperse fuel samples. The simulations show that incorporating statistical kinetics has an important effect on burnout predictions in certain cases, the importance increasing with decreases in temperature, mean reactivity, and breadth of the particle size distribution. 32 refs.
Download or read book British Reports Translations and Theses written by British Library. Document Supply Centre and published by . This book was released on 1995 with total page 768 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Energy Research Abstracts written by and published by . This book was released on 1993 with total page 490 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1979 with total page 1096 pages. Available in PDF, EPUB and Kindle. Book excerpt:
