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U.S. Department of Energy
Office of Scientific and Technical Information

Combustion research and ash fouling for low-rank coals

Technical Report ·
OSTI ID:7181727
It has been shown that under fine coal grinding, liberation of mineral phases will occur. One of the phases readily separated is SiO/sub 2/ or quartz. If this has occurred in the case of micronized coal, although the coal mineral phases are present, the intimate contact at high temperatures will not occur as often. This may explain the decreased amount of melilite noted in the outer sintered layer of deposits formed during combustion of micronized coal. Earlier work has proposed that phases in the melilite group are the glue that binds the deposits together and contributes to the deposit strength. The decreased strength noted in deposits from micronized coal combustion is also consistent with the decreased amount of melilite which would act as a binding agent joining the discrete mineral particles in the deposit. Micronized coal appears to produce deposits which are both smaller and have less strength than those noted in the combustion of larger particle size coal. Smaller ash particles, produced from the micronized coal, would contribute to decreased deposit size. The fluid dynamics would tend to cause smaller particles to follow the stream lines instead of impacting the tube surface. In addition, the finer grind appears to have altered the mineral phases impacting the tube surface, thus decreasing the stickiness or strength noted in deposits from a high sodium lignite coal. 8 references, 5 figures, 5 tables.
Research Organization:
North Dakota Univ., Grand Forks (USA). Energy Research Center
DOE Contract Number:
FC21-83FE60181
OSTI ID:
7181727
Report Number(s):
DOE/FE/60181-94; CONF-8406121-4; ON: DE84012875
Country of Publication:
United States
Language:
English