Ash chemistry in the U-GAS process: industrial medium-Btu fuel gas demonstration-plant program

Technical Report · Thu Feb 01 04:00:00 EST 1979

OSTI ID:6932337

The chemistry of the agglomeration of ash in IGT's U-GAS pilot plant runs on coke, run-of-mine Kentucky coal, and washed Kentucky coal has been investigated. Methods included optical and electron microscopy, chemical analyses, and fusibility tests. There is little difference in elemental composition of the ash among the three feeds. Agglomeration of ash into rounded beads occurred in runs on coke and washed coal through formation of an iron-rich, relatively low-melting matrix in which other ash is embedded. The matrix, a mixture consisting mainly of ferrous aluminum silicate, is formed by reaction of iron oxide with aluminosilicates (clay minerals) of the coal. Iron in coke is in a form suitable for this reaction to proceed. Iron in coal occurs mainly as pyrite, which loses half its sulfur to form ferrous sulfide when the coal is heated to bed temperature; the ferrous sulfide must then be oxidized to ferrous oxide before the reaction with the aluminosilicates can proceed. This oxidation occurred, and the ferrous aluminum silicate was formed in pilot plant tests with washed coal but not in tests with run-of-mine coal; however, the difference is attributed to differences in mode of operation rather than to the difference in feed. The gas composition in the reactor bed is thermodynamically unfavorable for oxidation of the ferrous sulfide except at regions near the oxygen inlet. The ferrous sulfide oxidation and ash agglomeration achieved with washed coal are attributed to the introduction of a greater portion of the oxygen into the venturi area than in previous tests.

• Research Organization: Institute of Gas Technology, Chicago, IL (USA)
• DOE Contract Number: AC02-77ET13046
• OSTI ID: 6932337
• Report Number(s): DOE/ET/13046-T79; ON: DE83003122
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
010404* -- Coal
Lignite
& Peat-- Gasification
010600 -- Coal
Lignite
& Peat-- Properties & Composition
AGGLOMERATION
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
ALUMINIUM SILICATES
ASHES
CHALCOGENIDES
CHEMICAL COMPOSITION
CHEMICAL REACTIONS
CHEMISTRY
COAL GASIFICATION
COKE
DATA
DEMONSTRATION PLANTS
DENSITY
DIAGRAMS
EXPERIMENTAL DATA
GASIFICATION
INFORMATION
IRON COMPOUNDS
IRON OXIDES
IRON SULFIDES
MELTING POINTS
MINERALS
NUMERICAL DATA
OXIDATION
OXIDES
OXYGEN COMPOUNDS
PARTICLE SIZE
PHASE DIAGRAMS
PHYSICAL PROPERTIES
PYRITE
RESIDUES
SILICATES
SILICON COMPOUNDS
SILICON OXIDES
SIZE
SOLID WASTES
SULFIDE MINERALS
SULFIDES
SULFUR COMPOUNDS
THERMOCHEMICAL PROCESSES
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
TRANSITION TEMPERATURE
U-GAS PROCESS
WASTES