Plastic behaviour of coal under rapid-heating high-temperature conditions

Fong, William; Khalil, Y.F.; Peters, William A.; Howard, Jack B.

doi:10.1016/0016-2361(86)90006-2

Cited by 66 publications

(37 citation statements)

References 6 publications

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“…Drawing on the work of Van Krevelen (1961) and Neavel ( 1 982) and studies in this laboratory (Schaub et al, 1985a, b;Fong et al, 1985Fong et al, , 1986a, it was concluded that softening occurs when a critical temperature and concentration of a thermally-derived plasticizing agent, known as metaplast, are reached. Some metaplast is assumed to preexist in the coal as a bitumenlike material.…”

Section: General Descriptionmentioning

confidence: 99%

“…However, quantitative information directly applicable to the present model is not easily obtained from these instruments due to poorly defined flow fields, and due to heating rates and temperatures below those of current interest. Using a coal plastometer specifically designed to overcome these limitations, Fong et al (1985Fong et al ( , 1986a measured a minimum viscosity of order lo3 Pa . s for molten Pittsburgh Seam bituminous coal at heating rates of several hundred "C /s and peak temperatures exceeding 5OOOC.…”

Section: Conservation Equationsmentioning

confidence: 99%

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An experimental and modeling study of softening coal pyrolysis

1989

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A quantitative model of softening coal pryolysis is developed and tested against observed behavior. The model treats intraparticle transport of gases and metaplast throughout the softening stage of pyrolysis via growth of bubbles uniformly dispersed in the molten coal. The model quantitatively describes the transient softening behavior including the initiation, duration, and magnitude of plasticity and swelling of the particle. The model kinetic parameters are derived from experiments, in which a highly softening Pittsburgh No. 8 bituminous coal was pyrolyzed, and total weight loss, and yields and molecular weight distributions of tars and pyridine extractables of cooled chars were measured. Model predictions of effects of pressure, particle diameter and temperature on tar yields and weight losses, of effects of pressure on swelling ratio, and of effects of heating rate on plasticity are presented. The model provides good fits to the laboratory data and predicts trends in pyrolysis behavior in good qualitative accord with expectations based on published data.

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Section: General Descriptionmentioning

confidence: 99%

Section: Conservation Equationsmentioning

confidence: 99%

An experimental and modeling study of softening coal pyrolysis

1989

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“…Extractables are a potentially valuable product, precursor, or recycle feed. Other data from Fong (1986) and Fong et al (1986) show an optimum treatment "severity" (temperature and time) for recovering large extract yields (up to about 70 wt.% of the starting material). Inadequate treatment provides too little conversion, while excess severity causes molecular weight growth and further conversion of the extracts to a carbonaceous residue (char or coke).…”

Section: Special Applicationsmentioning

confidence: 93%

“…Table 6 shows data from Fong (1986) and Fong et al (1986) on effects of temperature and treatment time on the major products from pyrolysis of a rather complex thermoplastic natural polymer (an eastern U.S. bituminous coal). External hydrogen was not employed in these experiments.…”

Section: Special Applicationsmentioning

confidence: 99%

High-flux solar photon processes: Opportunities for applications

Steinfeld¹,

Coy²,

Herzog³

et al. 1992

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EXECUTIVE SUMMARYThe overall goal of this study was to identify new high-flux solar photon (HFSP) processes which show promise of being feasible and in the national interest. Electric power generation and hazardous waste destruction were excluded from this study at sponsor request.Our specific objectives were: * to survey pertinent information bases; · to construct and assemble in prescribed electronic form a bibliography of relevant literature; * to prepare an initial list of potentially promising HFSP applications; to define a set of criteria for evaluating potential HFSP applications; * to carry out more detailed evaluations of some of the more promising applications; · to provide recommendations on HFSP process applications indicating special promise; * to discuss the status of current relevant research; and * to recommend research needed to advance basic understanding of HFSP applications and to further their potential for practicality.Our approach was to carry out the project with a core team of researchers providing expertise over a broad array of foundational topics, viz., chemical physics, optics, spectroscopy, photochemistry, high-temperature reactions, industrial chemistry, and chemical process engineering. Because of the wide range of scientific and engineering disciplines relevant to the study goals and the relatively short time available for the study, members of the core team carried out intense, round-table discussions with invited experts in a diverse sphere of pertinent disciplines, e.g., pure and applied optics, solar energy, furnace design, combustion, materials science and engineering, etc. Core team members conferred with experts at the Solar Energy Research Institute (SERI) (now known as the National Renewable Energy Laboratory, NREL) and the University of Chicago, and with participants in related studies being conducted by the National Academy of Sciences and SRI International, Inc. PC-compatible software was used to carry out an in-depth survey of post-1985 literature and to assemble in electronic form a bibliographic data base of important publications. Our approach emphasized the importance of delineating critical scientific and engineering foundations for identifying, evaluating, and discriminating among potentially promising options for HFSP applications. For example, limitations on solar photon intensity and wavelength and temporal variations in solar insolation impact process capacity, duty cycle, and controllability. Competition from alternative sources of intense photon fluxes was also considered in some detail. Formal economic and engineering cost estimates were outside our charter, but the study noted the importance of considering both conventional and externalized factors (e.g., environmental impacts, national security, global competitiveness, quality of fossil or other energy displaced) in determining overall costs of HFSP and competing options.Our overall conclusion is that there is promise for new applications of concentrated solar photons, especially in certain aspects of ...

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“…A number of viscosity models have been developed based on the metaplast theory [26][27][28][29]. However, neither the mechanism of tar escaping from particles nor the mechanism of soot condensation have been understood [22].…”

Section: Introductionmentioning

confidence: 99%

Fragmentation and diffusion model for coal pyrolysis

Chen

2011

Journal of Analytical and Applied Pyrolysis

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Plastic behaviour of coal under rapid-heating high-temperature conditions

Cited by 66 publications

References 6 publications

An experimental and modeling study of softening coal pyrolysis

An experimental and modeling study of softening coal pyrolysis

High-flux solar photon processes: Opportunities for applications

Fragmentation and diffusion model for coal pyrolysis

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