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Author : Richard John Quann
Publisher :
ISBN 13 :
Total Pages : 434 pages
Book Rating : 4.:/5 (14 download)
Download or read book Ash Vaporization Under Simulated Pulverized Coal Combustion Conditions written by Richard John Quann and published by . This book was released on 1982 with total page 434 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Ashok Kumar Sanwarmal Padia
Publisher :
ISBN 13 :
Total Pages : 658 pages
Book Rating : 4.:/5 (258 download)
Download or read book The Behavior of Ash in Pulverized Coal Under Simulated Combustion Conditions written by Ashok Kumar Sanwarmal Padia and published by . This book was released on 1976 with total page 658 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : A. S. Padia
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (5 download)
Download or read book The Behavior of Ash in Pulverised Coal Under Simulated Combustion Conditions written by A. S. Padia and published by . This book was released on 1976 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Aura Cecilia Davila Latorre
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (119 download)
Download or read book Ash Formation Under Pressurized Pulverized Coal Combustion Conditions written by Aura Cecilia Davila Latorre and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Coal combustion is a source of inorganic particulate matter (ash), which can deposit in boilers and also be emitted into the atmosphere becoming part of ambient fine particulate matter (PM 2.5). In order to decrease coal combustion emissions per unit of power produced, higher efficiency systems have been proposed, including systems operating at elevated pressures. These new operating conditions will affect pollutant formation mechanisms, particularly those associated with the conversion of mineral matter to ash. Ash particle formation mechanisms are particularly sensitive to changes in pressure as they are related to the structure of coal char particles at early stages of combustion. To assess the importance of pressure on ash particle formation, pyrolyzed chars and ash particles from pressurized pulverized combustion of two bituminous and one subbituminous U.S. coals at operating pressures up to 30 atm were studied. Pressure changes the distribution of char particle types, changing the spatial distribution of the minerals during the combustion process and therefore affecting particle formation mechanisms. Chars were examined by Scanning Electron Microscopy (SEM) and classified into two different types (cenospheric and solid) depending on porosity and wall thickness. A correlation for estimating the amount of these cenospheric char particles was then proposed for bituminous coals based on the operating conditions and coal maceral analysis. The ash particle size distribution of the coals combusted at different operating pressures was measured using Computer Controlled Scanning Electron Microscopy (CCSEM). The results of the char characterization and ash particle size distribution measurements were then incorporated into an ash particle formation algorithm that was proposed and implemented. The model predicts ash particle size and composition distributions at elevated pressures under conditions of complete char burnout. Ash predictions were calculated by first developing char structure distribution functions based on coal characteristics. To obtain an ash particle size distribution, carbon is then allowed to react away while following coalescence, fragmentation and other transformation processes as combustion proceeds. Particle size distributions calculated with this model showed qualitative agreement with the trends identified in the experimental portion of this research.
Author : Alan N. Sayre
Publisher :
ISBN 13 :
Total Pages : 22 pages
Book Rating : 4.:/5 (196 download)
Download or read book Properties of Ash Particles Generated During Pulverized Coal Combustion written by Alan N. Sayre and published by . This book was released on 1988 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author :
Publisher :
ISBN 13 :
Total Pages : 10 pages
Book Rating : 4.:/5 (873 download)
Download or read book Suppression of Fine Ash Formation in Pulverized Coal Flames. Quarterly Technical Progress Report No. 6, January 1, 1994--March 31, 1994 written by and published by . This book was released on 1994 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: During the present quarter the model was coded and tested on the Illinois coal. Some features of the process need discussion. After devolatilization, the char particle heats towards its steady-state combustion temperature. At approximately 1200--1300 K, the particle quickly goes from a temperature where the equilibrium sodium vapor pressure is negligible to a temperature where it is at one atmosphere. This shows that the sodium vaporization occurs under non-isothermal conditions, although the rapid rate of sodium diffusion relative to particle heating suggests that the quasi steady-state formulation for the sodium vaporization portion of the problem is appropriate. It also illustrates the two-stage release pattern for the sodium: (1) an early rapid release of organically-bound sodium, and (2) a more delayed release of acid-washable sodium, and sodium that was complexed into clay chemicals during the organic sodium vaporization. The conditions reported for the present calculations are as follows: Coal: 8.7% ash, 12% H2O, 33.5% volatile matter. Elemental sodium represent 0.82% of the ash. For purposes of calculation, the char particle is presumed to consist of the fixed carbon from the proximate analysis, along with the ash. This establishes the mass fraction of sodium and other minerals in the char at the start of char combustion. For the baseline condition, the char particle was assumed to be 50% covered by attached excluded mineral, and the included mineral matter was assumed to be divided into monodisperse 0.5 [mu]m particles that are evenly dispersed throughout the char. The diameter of the char particle was 25 [mu]m.
Author : Joseph John Helble
Publisher :
ISBN 13 :
Total Pages : 540 pages
Book Rating : 4.:/5 (178 download)
Download or read book Mechanisms of Ash Particle Formation and Growth During Pulverized Coal Combustion written by Joseph John Helble and published by . This book was released on 1987 with total page 540 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Guangxi Yue
Publisher : Springer
ISBN 13 : 981102023X
Total Pages : 604 pages
Book Rating : 4.8/5 (11 download)
Download or read book Clean Coal Technology and Sustainable Development written by Guangxi Yue and published by Springer. This book was released on 2016-07-30 with total page 604 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book gathers the proceedings of the 8th International Symposium on Coal Combustion. The contributions reflect the latest research on coal quality and combustion, techniques for pulverized coal combustion and fluidized bed combustion, special issues regarding CO2 capture (CCS), industrial applications, etc. – aspects that are of great importance in promoting academic communications between related areas and the technical development of coal-related fields. The International Symposium on Coal Combustion (ISCC), sponsored and organized by Tsinghua University since 1987, has established itself as an important platform allowing scientists and engineers to exchange information and ideas on the science and technology of coal combustion and related issues, and to forge new partnerships in the growing Chinese market. Researchers in the fields of clean coal combustion, carbon dioxide capture and storage, coal chemical engineering, energy engineering, etc. will greatly benefit from this book. Guangxi Yue, professor of the Department of Thermal Engineering in Tsinghua University, Beijing, China, and a member of Chinese Academy of Engineering(CAE). Shuiqing Li, professor of the Department of Thermal Engineering in Tsinghua University, Beijing, China.
Author : Robert Knappstein
Publisher :
ISBN 13 : 9783844060775
Total Pages : pages
Book Rating : 4.0/5 (67 download)
Download or read book Large Eddy Simulation of Pulverized Coal Combustion in the Context of Tabulated Chemistry written by Robert Knappstein and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Suppression of Fine Ash Formation in Pulverized Coal Flames. Final Technical Report, September 30, 1992--January 31, 1996 written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Coal ash, and particularly fine fly ash, remain one of the principal practical and environmental problems in coal-based power generation. In particular, submicron aerosols are identified with direct inhalation risk. Submicron ash is thought to arise from mineral vaporization during char combustion, followed by nucleation, condensation and coagulation to yield an aerosol. While aerosols are predominantly made out of volatile alkali minerals, they also can include refractory oxides that are chemically reduced to more volatile forms within the char particle and vaporized. Most of the ash of size greater than 1[mu]m is generated by agglomeration of mineral as the char particle bums out. These two principal mechanisms are thought to account for most of the ash generated in coal combustion. Previous research has shown that various forms of coal treatment can influence the yields of fine ash from combustion. The research reported here investigates various forms of treatment, including physical coal cleaning, aerodynamic sizing, degree of grinding, and combinations of these on both aerosol yields and on yields of fine residual ash (1-4[mu]m). The work also includes results from the combustion of artificial chars that include individual mineral elements. This research shows that these various forms of coal treatment can significantly change ash characteristics. While none of the treatments affected the bulk of the residual ash size distribution significantly, the yield of the ash aerosol mode (d
Author : L Lahaye
Publisher : Springer Science & Business Media
ISBN 13 : 9400936613
Total Pages : 505 pages
Book Rating : 4.4/5 (9 download)
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 Investigation of Mechanisms of Ash Deposit Formation from Low-rank Coal Combustion written by and published by . This book was released on 1987 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This project was undertaken to determine the chemical behavior of alkali metal and other species implicated in the ash fouling which can occur during the combustion of low rank coals. The coal combustion was studied in unaugmented premixed pulverized coal flames. Vapor species were measured by molecular beam mass spectrometry. Temperatures were also measured, and time-resolved coal/ash particulate samples were collected and analyzed. A major part of the research on this project was devoted to: (1) the development and refinement of techniques for the MBMS analysis of trace quantities of unstable and reactive high temperature vapor species from the pulverized coal flames; and (2) the time-resolved sampling and collection of particulates. The equipment is now operating very satisfactorily. Inorganic species, some of which were present at parts-per-million levels, were quantitatively sampled and measured in the pulverized coal flames. Time-resolved particulate samples which were free of vapor deposited contaminants were collected without the use of an interfering substrate. Profiles of the alkali metal species in Beulah lignite and Decker subbituminous coal flames were obtained. It was found in both flames that sodium is volatilized as the atomic species early (milliseconds) in the combustion process. The gaseous Na reacts, also in milliseconds, to form an unknown species which is probably an oxide fume, but which is not NaOH or Na2SO4. This is probably the mechanism for the formation of the alkali ''fumes'' observed in other systems. Measurements were also made of a number of other gaseous species, and time-resolved coal/ash samples were obtained and analyzed. 27 refs., 23 figs., 8 tabs.
Author :
Publisher :
ISBN 13 :
Total Pages : 7 pages
Book Rating : 4.:/5 (683 download)
Download or read book Suppression of Fine Ash Formation in Pulverized Coal Flames. Quarterly Technical Progress Report No. 10, January 1, 1995--March 31, 1995 written by and published by . This book was released on 1995 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: The production of ash particles from coal combustion limits it's use as a fuel. On mechanism by which small ash particles are formed is the generation of submicron aerosols through a vaporization/condensation mechanism. Previous work has shown that coal cleaning can lead to increased emissions of aerosols. This research will investigate the means or aerosol formation in coals and the effects that various methods of coal cleaning have on aerosol production, and whether or not cleaning can be performed in a manner that will not lend itself to aerosol formation.
Author :
Publisher :
ISBN 13 :
Total Pages : 9 pages
Book Rating : 4.:/5 (727 download)
Download or read book Suppression of Fine Ash Formation in Pulverized Coal Flames written by and published by . This book was released on 1993 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: The second major ash producing mechanism is the generation of a submicron aerosol through a vaporization/condensation mechanism. When the ash size distribution is plotted in terms of number density, the submicron mode generally peaks at about 0. 1 [mu]m. When plotted in terms of mass, this mode is sometimes distinct from the residual ash mode, and sometimes merged into it. During diffusion-limited char combustion, the interior of the particle becomes hot and fuel-rich. The non-volatile oxides (e.g., Al[sub 2]O[sub 3], SiO[sub 2], MgO, CaO, Fe[sub 2]O[sub 3]) can be reduced to more volatile suboxides and elements, and partially vaporized. These reoxidize while passing through the boundary layer surrounding the char particle, thus becoming so highly supersaturated that rapid homogeneous nucleation occurs. This high nuclei concentration in the boundary layer promotes more extensive coagulation than would occur if the nuclei were uniformly distributed across the flow field. The vaporization can be accelerated by the overshoot of the char temperature beyond the local gas temperature. Although these particles represent a relatively small fraction of the mass, they can present a large fraction of the surface area. Thus, they are a preferred site for the condensation of the more volatile oxides later in the furnace. This leads to a layering effect in which the refractory oxides are concentrated at the particle core and the more volatile oxides resideat the surface. This also explains the enrichment of the aerosol by volatile oxides that has been noted in samples from practical furnaces. These volatile metal oxides include the majority of the toxic metal contaminants, e.g., mercury, arsenic, selenium and nickel. Risk assessment studies suggest that toxic metal emissions represent a significant portion of the health risk associated with combustion systems.
Author : Jim Williamson
Publisher : Taylor & Francis
ISBN 13 : 1351410261
Total Pages : 1103 pages
Book Rating : 4.3/5 (514 download)
Download or read book The Impact Of Ash Deposition On Coal Fired Plants written by Jim Williamson and published by Taylor & Francis. This book was released on 2022-10-12 with total page 1103 pages. Available in PDF, EPUB and Kindle. Book excerpt: Coal provides almost 40% of the world's electricity, and despite the understandable concern with respect to the environmental impact associated with coal use, forecasts from the International Energy Agency predict, that worldwide coal use will increase by up to 2% per annum until the year 2OlO. Faced with this increase, it is clearly important that the most efficient and environmentally acceptable clean coal technologies are available. This book is comprised of the proceedings of the Engineering Foundation Conference held in June 1993 in England. The objective of the conference was to present ideas on methods of predicting and reducing the effects of ash deposition in coal conversion systems, highlighting the problems experienced in industry, considering both utilities and industrial plants, and providing a view of the technology of coal ash deposition and its impact. Better techniques are needed to reduce the impact of ash deposition in coal fired plants, and these proceedings should form a reference document for anyone either experiencing slagging or actively engaged in trying to understand or eliminate the phenomenon.
Author : Aura Cecilia Dávila Latorre
Publisher :
ISBN 13 :
Total Pages : 568 pages
Book Rating : 4.:/5 (624 download)
Download or read book Ash Formation Under Pressurized Coal Combustion Conditions written by Aura Cecilia Dávila Latorre and published by . This book was released on 2005 with total page 568 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Modeling of Ash Deposition in a Pulverized-coal Boiler by Direct Simulation Monte Carlo Method written by and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
