Pilot-scale investigation of closed-loop fly-ash sluicing. Volume 2. Appendices. Final report
The report gives results of a pilot-scale demonstration of the technical feasibility of closed-loop operation of fly-ash sluicing systems. Chemical species leached from the ash increase the dissolved solids concentration of recycled sluice water to a point where equipment scaling may occur. Tests were conducted at two power plants using a 50-gpm pilot unit to demonstrate the feasibility of closed-loop operation, both with and without sluice water treatment. An ash-sluice computer process model was developed to predict chemistry and process conditions in full-scale systems. Fly-ash sluicing systems handling highly reactive alkaline ashes cannot be operated closed-loop without treating the sluice-water to control scale formation. Adding acid to adjust pH was effective in controlling calcium carbonate scale formation in the sluice water return line; however, it increased the potential for gypsum scale formation. Gypsum was ultimately the limiting species that prevented reliable closed-loop operation at the plants tested. Increased ash/water contact time in a reaction tank was not adequate to control the potential for gypsum scale formation at the residence time tested. The ash-sluice computer process model proved to be accurate in predicting the chemical composition and potential for scale formation in the pilot unit.
- Research Organization:
- Radian Corp., Austin, TX (USA)
- OSTI ID:
- 5388442
- Report Number(s):
- PB-85-204386/XAB; RAD-83-211-004-35
- Resource Relation:
- Other Information: See also Volume 1, PB85-204378
- Country of Publication:
- United States
- Language:
- English
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FLY ASH
AIR POLLUTION ABATEMENT
LEACHATES
FOSSIL-FUEL POWER PLANTS
GYPSUM
MATHEMATICAL MODELS
PILOT PLANTS
SCALING
AEROSOL WASTES
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FUNCTIONAL MODELS
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SOLUTIONS
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