Reaction kinetics and physical mechanisms of ash agglomeration: Final report

Technical Report · Sun May 01 04:00:00 EDT 1988

OSTI ID:6663266

Carty, R H; Mason, D M; Babu, S P

Several significant insights into the mechanisms and chemistry of the formation of ash agglomerates have been made: (1) The reaction of iron-and-calcium-containing components of coal ash with the siliceous components is critical for the formation of relatively low-melting aluminosilicates that makes it possible to form ash agglomerates in a fluidized-bed coal gasifier. (2) The association of the calcium and/or iron components with the siliceous components in single particles differs greatly from one coal to another. (3) One result of the variation in the association of the ash components is that the availability of low-melting agglomerative product also varies from coal to coal. Another result is that it is likely that the ease of agglomeration of the whole of the ash by collision with low-melting material will also vary. (4) The viscosity-temperature relationship of the ash reaction products is their most important property affecting the rate of agglomeration among reaction products and of the reaction products with unreacted ash. (5) In reactivity tests, approximately 2200/degree/F was found to be the minimum temperature for oxidation of ferrous sulfide and the onset of reaction of the oxidation product with siliceous minerals within a period of a few seconds. The latter reaction, which is critical to the formation of the iron aluminosilicate matrix of the ash agglomerates, can occur at temperatures as low as 1800/degree/F but at a much slower rate. The high temperature of the jet region, as well as its oxidizing atmosphere, is necessary for formation of the low-melting agglomerative matrix material. (6) Phase diagrams showing the effect of gasifier atmosphere on equilibrium among ferrous sulfide and its products have been prepared to cover part of the range of conditions that can be encountered in the gasifier. 47 refs., 60 figs., 42 tabs.

• Research Organization: Institute of Gas Technology, Chicago, IL (USA)
• DOE Contract Number: AC21-84MC21313
• OSTI ID: 6663266
• Report Number(s): DOE/MC/21313-2593; ON: TI88010266
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
010404* -- Coal
Lignite
& Peat-- Gasification
AGGLOMERATION
ASHES
CARBONACEOUS MATERIALS
CHEMICAL COMPOSITION
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
COAL
COAL GASIFICATION
COMPARATIVE EVALUATIONS
CORRELATIONS
DIAGRAMS
ELEMENTS
ENERGY SOURCES
FLUIDIZED BEDS
FOSSIL FUELS
FUELS
GASIFICATION
IRON
IRON COMPOUNDS
KINETICS
MATERIALS
MEASURING METHODS
METALS
MINERALS
NONMETALS
OXYGEN
PHASE DIAGRAMS
PHASE STUDIES
REACTION KINETICS
RESIDUES
SILICON COMPOUNDS
SLAGS
SULFUR
TEMPERATURE DEPENDENCE
THERMOCHEMICAL PROCESSES
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
VISCOSITY