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Comparison of low-rank coal ash sintering characteristics with pilot plant ash fouling tendencies

Conference ·
OSTI ID:6530154
The objective of this work was to develop a simple laboratory test for evaluating the fouling tendencies of low-rank coal ashes. Simultaneous ash shrinkage-electrical resistance measurements were performed to determine the sinter points of various coal ashes. In addition, the compressive strength of sintered ash pellets was determined to give an indication of the apparent bonding strength. The factors studied include ash composition, ash time-temperature history and particle size. Sintering tests appeared, from this preliminary evaluation, to be a satisfactory bench-scale method for evaluating the fouling behavior of low-rank coals. These tests correlated well with the observed fouling behavior of coals in the UNDERC test furnace. There was a strong correlation between pilot plant ash fouling tendency and the amount of shrinkage observed and the compressive strength of ASTM and fly ash samples heated above their sinter points. In summary, the small amount of material required, the ability to use laboratory-produced ash rather than fly ash, and the low cost of the techniques are desirable characteristics for a test of fouling propensity. In addition, these techniques should prove useful in studies to clarify the mechanisms of particle-to-particle bonding involved in deposit formation. This together with information of the metal-ash bonding should help to both explain and predict fouling behavior of low-rank coal in combustion systems. 10 references, 9 figures, 5 tables.
Research Organization:
North Dakota Univ., Grand Forks (USA). Energy Research Center
DOE Contract Number:
FC21-83FE60181
OSTI ID:
6530154
Report Number(s):
DOE/FE/60181-64; CONF-840729-1; ON: DE85000916
Country of Publication:
United States
Language:
English