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Book Reviews Trends in the Use of Coal Ash. By Lesley Sloss, 1999. IEA Coal Research, Gemini House, 10-18 Putney Hill, London SW 15 6AA U.K. ISBN 92-9029-332-2. IEACCC/22 price to IEA member countries, $135. This is another in a long series of summary reports on the worldwide usage of coal by IEA Coal Research’s Clean Coal Center. Although this report easily stands on its own, it does extend and update two earlier IEA publications. These are Pulverized Coal Ash-Requirements for Utilization, by Sloss, Smith and Adams, 1996, and Residues from Advanced CoalUse Technologies, also by Sloss, 1996. Taken together, these three publications represent an excellent and accessible overview of the chemical and physical nature, use, and disposal practices for almost all types of coal combustion products. The emphasis of Trends in the Use of Coal Ash is on issues relative to the marketing of coal ash, primarily for cement and concrete applications. The first part of the report presents a short but useful summary of the different types of coal combustion ash, their morphology, and chemical characteristics. A discussion of loss on ignition (LOI) and its importance in marketing, along with recent developments in online carbon monitoring systems, is also presented. The report also provides worldwide coverage of marketing specifications and standards for coal use in cement. A comparison is presented between ASTM C-618 specifications for fly ash and the newer European standard EN450, as well as standards from other countries. On a global basis, legislation and guidelines for ash use and disposal are found to be highly variable and occasionally at odds with one another. Organizations such as the American Coal Ash Association have been formed in Europe (ECOBA) and Japan (CCUJ) to reduce institutional barriers and promote utilization. Fuel and combustion conditions from blending coals, cofiring with other fuel types such as biomass, low NOx burner conversion, and SCR and SNCR (selective catalytic reduction, selective non-catalytic reduction) technologies for NOx control are reported to affect the quality of the ash. Adverse effects include increase in LOI, increase in alkali concentration, or, in the case of SNCR or SCR, the addition of ammonia salts to the ash. These effects have resulted in the development of technologies to process and beneficiate fly ash to improve its quality. These approaches include size classification, grinding, and blending to enhance the consistency of the ash. Froth flotation, electrostatic separation, and carbon burn-out are used to separate carbon and reduce LOI. The current state of these technologies is covered in the report. One of the most useful and interesting roles of IEA publications is the presentation of a global perspective. A comprehensive survey of ash production and utilization practice is presented for 20 countries, from Australia to the United States, representing the vast bulk of the world’s coal consumption. In general, the United States is found to lag behind much of Europe, particularly Germany, the Netherlands, and Italy, who use almost all of their ash, as well as Japan and Israel, who use 2/3 or more. The U. S. utilization rate of about 1/3 is approximately the same as that of China and Canada, and greatly surpasses that of India and Russia. In general, the utilization of coal ash has shown a steady increase worldwide over the past decade. A short discussion of other applications for coal ash, such as in agriculture and waste stabilization, and “no-cement” concrete from fluidized bed combustion materials, is presented. The publication concludes with some short remarks on barriers to utilization.
I found the publication presented a very broad treatment of the subject, touching on most aspects of coal ash utilization. The report did have a strong emphasis on cement and concrete applications. The treatment of fluidized bed ash and scrubber sludge was less comprehensive, somewhat uneven, and occasionally confusing. This is probably due to the fact that the utilization of these materials lags behind that of conventional PCC ash. These materials may have been best treated separately. In general, Dr. Sloss has written a very useful and readable report. If you like reading about coal combustion products as much as I do, this report will be a “must have” addition to your library. If your checkbook is in dollars instead of pounds, the IEA publications are available from the Center for Applied Energy Research, the University of Kentucky, 2540 Research Park Drive, Lexington, Kentucky 40511-8410, U.S.A. (Attention: Theresa Wiley). Discounts are available for educational establishments. Tom Robl, Center for Applied Energy Research, University of Kentucky, 2540 Research Park Drive, Lexington, KY 40511-8410 EF000029O 10.1021/ef000029o
Clathrate Hydrates of Natural Gases, 2nd Ed. Revised and Expanded by E. Dendy Sloan, Jr. Marcel Dekker, Inc.: New York, 1998; 705 pp. Software Included. $195.00. Given the rapid advancement of gas-hydrate research over the past decade and the escalating interest in this class of nonstoichiometric icy compounds as a hydrocarbon resource, as a manufactured material, and as a potentially major player in global issues of climate and seafloor stability, Clathrate Hydrates of Natural Gases, 2nd Ed. is a welcomed revision of its excellent predecessor. This second edition monograph by E. Dendy Sloan, Jr. updates the level of understanding from nearly 60 years of active research, providing a single record of most of the thermodynamic data obtained since 1934 (i.e., following the pivotal discovery of gas hydrates as the bane of gas transmission lines, which re-focused initial intrigue in gas hydrates from laboratory curiosity to more practical interests). Both theoretical and experimental lines of research are addressed in considerable detail, lending both academic and industrial perspectives to this reference book. Also provided is a comprehensive reference list of well over 1000 investigations and reports, most of which are at least briefly described in the main text. In fact, it should be noted that this monograph is not crafted as a standard textbook, per se; rather, it is a well-integrated compendium of research methods, results, and interpretations reported from numerous investigators around the globe, tied together by the key issues, concepts, and perspectives that have emerged from the literature over the last half-century. This monograph thus serves as a combination textbook/reference book/historical purview/ literature survey on the general topic of gas hydrates. The scope and format of the book follows that of the first edition, with updated information included where appropriate. The opening chapter presents an overview and historical perspective of gas hydrates. Their early laboratory discovery (ca. 1800), identification, and classification are chronicled, followed by a brief review of the more recent research trends motivated largely by gas production and processing problems,
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discovery of their in situ occurrence in marine, permafrost, and outer solar system environments, and realization of their potential as both an energy resource and possible geohazard. The following chapters provide detailed development of the work performed in these areas, along with examples of industrial interest. The information and topics covered include: the molecular and macroscopic properties of hydrate structures I, II, and H, and how these compare to water ice; kinetics of hydrate formation, dissociation, and inhibition, including detailed phase diagrams and prediction schemes for numerous hydrocarbon + water systems; effects of a variety of inhibitors on hydrate formation; a statistical thermodynamic model for hydrate phase equilibria prediction; experimental apparatus and methods used for laboratory synthesis of hydrates; direct measurement of phase equilibria, kinetics, transport, and thermal properties; extent and location of in situ gas-hydrate occurrences in marine and permafrost environments; geophysical and geochemical indicators of their in situ occurrence; gas recovery from hydrated reservoirs; economic evaluation of gas production from hydrates; methods and models for gas hydrate recovery; and common industrial problems and solutions concerning hydrates in processing, transportation, and production procedures. Like the first edition, the second also includes two appendices to augment the accompanying disk of PC-compatible computer programs. (Mac-compatible versions are not offered, unfortunately.) The first appendix discusses fugacity coefficients, enthalpy and entropy changes, and the use of a supplied program for estimating thermodynamic conditions related to hydrate formation. The second discusses the program CSMHYD for estimating equilibrium conditions of hydrate formation (either with or without inhibitors) and provides notes and examples to aid in proper use of (and expectations from) the program. New information provided exclusively in the second edition includes recent advancements in the knowledge of in situ hydrates, including the discovery of structure H hydrates in natural settings and the significant progress in their characterization; recent work on the kinetics of nucleation, growth, and inhibition; new data on phase equilibria; new prevention and dissociation methods in production and processing; and a revised (and more user-friendly) computer program that now includes structure H, salt mixtures, and methanol concentrations up to 50 wt %.
Book Reviews The primary limitations of this monograph are few, and are noted by Professor Sloan in the preface; namely, that the focus of the book is on clathrate hydrates of components found in natural gases, and other hydrate formers are generally excluded (although, as noted, the principles of crystal structure, thermodynamics, and kinetics discussed in the book still apply). Secondly, that this edition still retains a somewhat Western Hemisphere perspective due to language barriers, literature access, and space constraints. This reviewer notes that there are also occasional assumptions in the text that may lead to some slight misunderstanding for the nonspecialist reader. For instance, some of the property measurements reported for a given structure of hydrate (I, II, or H) are those made on hydrates that are readily formed in the laboratory but that rarely occur in nature, such as ethylene oxide hydrate and THF hydrate for structure I and II properties, respectively. Such hydrates have commonly been used as analogue material for hydrates of far greater scientific and commercial interest (such as pure methane hydrate, CO2 hydrate, or propane hydrate) that are often more difficult to synthesize in the laboratory in a pure form suitable for material testing. However, given that the intent of this monograph is to provide a unified compilation of widely ranging research, any implicit assumptions or gaps in the text are either reflective of the current level of knowledge of this ever-growing field of science, or due to the enormous scope of the subject matter covered here. Simply put, Clathrate Hydrates of Natural Gases, 2nd Ed. is the definitive source on the subject of gas hydrates. This second edition monograph by Professor Sloan does the hydrate community a tremendous and unparalleled service by integrating 60 years of gas hydrate research into a logical, useful, and relevant framework. This book is a must-have for researchers, students, engineers, and industrial practitioners alike. Laura A. Stern, U.S. Geological Survey, 345 Middlefield Rd., MS/ 977, Menlo Park, CA 94025. EF000056E 10.1021/ef000056e
