Pyrite thermochemistry, ash agglomeration, and char fragmentation during pulverized coal combustion

Technical Report · Wed Nov 01 04:00:00 EST 1989

DOI:https://doi.org/10.2172/5339245· OSTI ID:5339245

Akhtar, S.

During p.f. firing of coal, the evolution of particulate ash from extraneous mineral matter is determined by thermochemistry, agglomeration of molten inclusions as the char is consumed, and fragmentation of the char into finer particulates. Our three-year research program aims for a fundamental understanding of these chemical and physical dynamics, to motivate control strategies for fouling and slagging problems. The transformation of pyrite inclusions into iron oxide ash is the primary focus, including pyrite thermochemistry, the average number of ash particles per char particle, and the relation between the size distributions and composition of mineral inclusions and ash particles. During the quarter June -- September 1989, the transformation of iron pyrite suspensions during pyrolysis was monitored at heating rates and furnace temperatures typical of pulverized fuel (p.f.) firing. Solid samples which represent various residence times and thermal histories have been prepared in a radiant suspension flow reactor, and subjected to x-ray diffraction analysis. The relative proportions of pyrite and the aggregate amount of pyrrhotite and iron sulfide melt are reported for furnace temperatures from 1100K to 1550K at a fixed nominal residence time of several hundred milliseconds. In a separate study at a furnace temperature of 1560K, the transient evolution of the iron ash composition is reported for a range of nominal residence times. 6 refs., 5 figs.

• Research Organization: Stanford Univ., CA (USA). High Temperature Gasdynamics Lab.
• Sponsoring Organization: DOE/FE
• DOE Contract Number: FG22-87PC79909
• OSTI ID: 5339245
• Report Number(s): DOE/PC/79909-T2; ON: DE90004263
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
014000* -- Coal
Lignite
& Peat-- Combustion
AGGLOMERATION
ASHES
CARBONACEOUS MATERIALS
CHALCOGENIDES
CHEMICAL REACTIONS
COAL
COMBUSTION
ENERGY SOURCES
FOSSIL FUELS
FOULING
FRAGMENTATION
FUELS
FURNACES
IRON COMPOUNDS
IRON SULFIDES
MATERIALS
MINERALS
OXIDATION
PULVERIZED FUELS
PYRITE
PYRRHOTITE
RESIDUES
SULFIDE MINERALS
SULFIDES
SULFUR COMPOUNDS
THERMOCHEMICAL PROCESSES
TRANSITION ELEMENT COMPOUNDS
VERY HIGH TEMPERATURE