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About: Carbochemistry is a(n) research topic. Over the lifetime, 1010 publication(s) have been published within this topic receiving 16626 citation(s).
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17 Nov 1993
Abstract: Part 1 Coal Typology: Coal as an economic good Coal as fuel and raw material Coal as an organic sediment Coal as a rock Coal as a biological debris Coal as an evolving organic chemical complex Coal as a solid colloid Coal as an enigma in solid state physics Coal as an object of classical chemical analysis Coal as an object of physical analysis. Part 2 Coal Physics: Physical properties and the additivity concept Volumetric properties Optical properties Electrical properties Magnetic properties Mechanical properties Cohesive and interfacial energy properties Thermal properties. Part 3 Coal Chemistry: The action of solvents on coal The action of oxidizing agents on coal Action of air and molecular oxygen on coal The action of hydrogen on coal The action of heat on coals The "grand processes" of coal utilization. Part 4 Coal Constitution: The chemical and physical nature of coals Coal analogues Coalification revisited Coal research. Part 5 Compendium.

491 citations

Journal ArticleDOI
Abstract: Low rank coals are generally featured with a high water content which exerts strong influences onto their utilization including pyrolysis, gasification, liquefaction and combustion. Understanding of fundamental aspects of coal moisture and its effects on physical and chemical characteristics of coal and coal–water interaction are very important in order to develop technologies to remove coal water effectively. This paper provides a comprehensive overview on the fundamental understanding of water in brown coal and lignite, including the physical and chemical structure of coal, the forms of water present in low rank coals, migration of water during drying, coal structure changes during moisture loss, moisture re-adsorption, and effects of water removal on subsequent applications including combustion, gasification and liquefaction. Applications of techniques such as NMR, DSC and FTIR in determination and quantification of types of water and coal structures are also summarized.

452 citations

Journal ArticleDOI
01 Sep 1984-Fuel
Abstract: Using detailed chemical analyses of both coal and products from various liquefaction schemes, molecular models have been constructed to show the steps in the conversion process, and the nature of the products. Products from short- and long-contact time dissolution are shown in relation to structures found in the parent coal. Such molecules are highly functional, high molecular weight materials, which are difficult to process by conventional methods and tend to associate causing product stability problems. In contrast, products from two-stage liquefaction have greatly reduced molecular weight and functionality, and are consequently more amenable to downstream processing. The accurate and quantitative presentation of models reflects the analytical data on the coal and liquefaction products in terms of elemental distribution, aromaticity, functional group chemistry, and reactivity.

293 citations

Journal ArticleDOI
Abstract: Despite their vast reserves, low-rank coals are considered undesirable because their high moisture content entails high transportation costs, potential safety hazards in transportation and storage, and the low thermal efficiency obtained in combustion of such coals. Their high moisture content, greater tendency to combust spontaneously, high degree of weathering, and the dusting characteristics restrict widespread use of such coals. The price of coal sold to utilities depends upon the heating value of the coal. Thus, removal of moisture from low-rank coals (LRC) is an important operation. Furthermore, LRC can be used cost effectively for pyrolysis, gasification, and liquefaction processes. This article provides an overview the diverse processes—both those that utilize conventional drying technologies and those that is not yet commercialized and hence in need of R&D. Relative merits and limitations of the various technologies and the current state of their development are presented. Drying characteristics ...

245 citations

Journal ArticleDOI
01 Oct 1985-Fuel
Abstract: The reactivities of 34 coal chars of varying rank with H2O have been determined to examine the effect of coal rank on the gasification rate of coal char. The reactivities of chars derived from caking coals and anthracites (carbon content > 78 wt%, daf) were very small compared with those from non-caking (lower-rank) coals. The reactivities of low-rank chars do not correlate with the carbon content of the parent coals. To clarify which factor is more important in determining the reactivity, the evolution of CO and CO2 from char, the moisture content of char and the amount of exchangeable cations were determined for these low-rank coals or their chars. These values were considered to represent the amount of active carbon sties, the porosity and the catalysis by inherent mineral matters, respectively. It was concluded that the amount of surface active sites and/or the amount of exchangeable Ca and Na control the reactivity of low-rank chars in H2O.

220 citations

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