Chemical structure changes of coal, char, and tar during devolatilization

Conference · Sat Dec 31 04:00:00 EST 1994

OSTI ID:254686

Fletcher, T H ^[1]; Pugmire, R J ^[2]

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1. Brigham Young Univ., Provo, UT (United States)
2. Univ. of Utah, Salt Lake City, UT (United States)

Enormous progress has been made in coal pyrolysis research during the last decade. Models of coal devolatilization have progressed from simple rate expressions based on total mass release to empirical relationships based on the elemental composition of the parent coal to models that attempt to describe the macromolecular network of the coal. Measurements of particle temperature during devolatilization have eliminated much of the controversy regarding overall rates of devolatilization. In the last several years, advancements in chemical analysis techniques have allowed quantitative investigations of the chemical structure of both coal and its pyrolysis products, including the nature of the resulting char. A prominent research goal is to accurately predict the rates, yields, and products of devolatilization from measurements of the parent coal structure. This goal necessitates modeling the reaction processes on the molecular scale, with activation energies that relate to chemical bond breaking rather than release of products from the coal. {sup 13}C and {sup 1}H NMR spectroscopy have proven particularly useful in obtaining average values of chemical structure features of coal, char, and tar. This paper reviews experimental data regarding chemical structure features of coal, char, and tar during rapid devolatilization, and how these data have impacted the development and input parameters for devolatilization models. In particular, the relationship between pyridine extract yields and extract yields predicted purely from NMR chemical structure data is discussed.

• OSTI ID: 254686
• Report Number(s): CONF-940813--
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
66 PHYSICS
CARBON 13
CHARS
CHEMICAL ANALYSIS
COAL
COAL TAR
DEVOLATILIZATION
MOLECULAR STRUCTURE
NMR SPECTRA
PYRIDINE
PYROLYSIS
YIELDS