Ash and slag characterization for low-rank coals
Inorganics in low-rank coals are found in three major modes: ion exchangeable salts of the humic acid groups; mineral phases that are acid soluble, such as carbonates and some oxides; and insoluble minerals such as clays, quartz, and pyrite. The variation in association of inorganics has an effect on their fate during ashing. Determination of the extent to which inorganics are lost and mineral phases change during a carefully controlled set of ashing conditions is very important in understanding what changes may occur during coal processing and how such changes are related to process conditions. Numerous attempts have been made to develop empirical equations for calculating the viscosity-temperature relationship for coal ash slags from their composition. Since the composition of low-rank coal slags differs significantly from bituminous slags, the predictive equations in the literature often fail to give valid trends when applied to low-rank coal slags. Thus, a data base of experimentally determined viscosities of low-rank coal slags is required, combined with chemical or mineralogical characterization of the melts. This data base would then be used for the development of appropriate equations specific to low-rank coal slags. As research, development, and design work continue on slagging processes for combustion and gasification, it is increasingly important to have data on other thermophysical properties of low-rank coal slags, such as the surface tension, specific heat, thermal conductivity, and diffusivity. Determination of these properties requires the development of appropriate high-temperature equipment for property measurement, the compilation of a data base for a suite of low-rank coal slags, and the correlation of these properties with composition.
- Research Organization:
- North Dakota Univ., Grand Forks (USA). Energy Research Center
- DOE Contract Number:
- FC21-83FE60181
- OSTI ID:
- 6997197
- Report Number(s):
- DOE/FE/60181-97; CONF-840695-1; ON: DE84012922
- Resource Relation:
- Conference: 4. annual advanced gasification contractors' meeting, Morgantown, WV, USA, 26 Jun 1984; Other Information: Portions are illegible in microfiche products
- Country of Publication:
- United States
- Language:
- English
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Ash and slag characterization for low-rank coals
Mineral transformations during ashing and slagging of selected low-rank coals
Related Subjects
ASHES
CHEMICAL COMPOSITION
MELTING POINTS
PHASE TRANSFORMATIONS
COAL
SLAGS
PHYSICAL PROPERTIES
SURFACE TENSION
CORRELATIONS
LIGNITE
SPECIFIC HEAT
SUBBITUMINOUS COAL
TEMPERATURE DEPENDENCE
THERMAL CONDUCTIVITY
VISCOSITY
X-RAY DIFFRACTION
X-RAY FLUORESCENCE ANALYSIS
BROWN COAL
CARBONACEOUS MATERIALS
CHEMICAL ANALYSIS
COHERENT SCATTERING
DIFFRACTION
ENERGY SOURCES
FOSSIL FUELS
FUELS
MATERIALS
NONDESTRUCTIVE ANALYSIS
RESIDUES
SCATTERING
SURFACE PROPERTIES
THERMODYNAMIC PROPERTIES
TRANSITION TEMPERATURE
X-RAY EMISSION ANALYSIS
010600* - Coal
Lignite
& Peat- Properties & Composition