Study on the mechanism of the coal ash deposit and growth in the gasifier -- Relationship between ash melting characteristics and deposition characteristics
The phenomenon of coal ash deposition on the furnace walls is observed in a coal fired boiler or a coal gasifier. The deposits interfere with heat transfer and if they are heavy, they can interfere with operation and cause unplanned shut-downs. Therefore, a great deal of research on the subject has been conducted for many years and some slagging/fouling indices has been proposed. Most of these indices, that are based on viscosity, are used to predict deposition tendency in a boiler. The gasifier, however, has the region in which deposition tendency is difficult to predict with viscosity only. The gasifier can be divided into three regions. The lower region of the gasifier is the hottest part in which gas temperature is higher that the ash fluidizing point for discharging molten ash. In the middle region, it rapidly decreases to a level near the ash softening point by endothermic reaction of coal and in the upper region, it becomes lower than the ash softening point. Because this region is mostly below a critical viscous temperature and has both completely and partly melted ash particles, the evaluation of the ash deposition is difficult. This study focuses on the change in ash melting characteristics accompanied with change of temperature, the differences in deposition among several coal types are investigated with the research of correlation between ash deposition characteristics and ash liquid phase ratios.
- Research Organization:
- Central Research Inst. of Electric Power Industry (JP)
- OSTI ID:
- 20034342
- Resource Relation:
- Conference: 25th International Technical Conference on Coal Utilization and Fuel Systems, Clearwater, FL (US), 03/06/2000--03/09/2000; Other Information: PBD: 2000; Related Information: In: 25th international technical conference on coal utilization and fuel systems: Proceedings, by Sakkestad, B.A. [ed.], 969 pages.
- Country of Publication:
- United States
- Language:
- English
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