A novel high efficiency fine particulate and mercury control device. Final report for the Department of Energy Contract Number DE-FG02-95ER81968
This Phase II SBIR program was conducted to demonstrate the ability of a circulating fluidized bed (CFB) of flyash to cause particle agglomeration and consequent reduction in the quantity of fine particulate emissions from the system. Another objective was to show that carbon addition to the bed would result in the removal of mercury compounds from the flue gas at carbon utilization levels significantly better than duct injection of activated carbon. The pilot-scale testing was carried out in 1997. The pilot-scale fluid bed reactor was a 1000 CFM system, drawing gas from a slipstream of the exhaust of a 325 MW coal-fired boiler. Flue gas for the pilot unit was drawn downstream of the air preheater and returned to the same unit. Particle agglomeration testing was carried out for which the parameters of gas flow rate and water evaporation rate were varied, and the particle size distribution leaving the fluid bed system was monitored. The bed was able to cause a reduction in total particulate concentration by a factor of 10 and in fine particulate concentration by a factor of 5, and it was found that the best agglomeration of particles was obtained with simultaneous water spray evaporation. Tests were then carried out in which activated carbon was added to the fluid bed for mercury adsorption. Carbon addition in the bed was shown to yield both higher Hg removal and higher carbon utilization than normal carbon addition with the bed. The fluid bed fly ash alone, without the injection of activated carbon, will capture 50% of the inlet Hg vapor. A total of 80% removal of Hg vapor is achieved with the addition to the bed of 1000 g iodine impregnated activated carbon per gram of inlet Hg. The ability of the fluid bed to capture SO{sub 2} and HCl was also evaluated, using hydrated lime added to the bed. It was found that the fluid bed alone, without lime injection, removed 16% of the SO{sub 2}. Complete utilization of hydrated lime is achieved for SO{sub 2} removal at mole ratios up to 0.66, and concomitant to the SO{sub 2} removal, over 90% of the HCl was removed. It is clear that this multipollutant control device can address both PM{sub 2.5} issues, as well as potential Hg vapor emission regulations.
- Research Organization:
- Environmental Elements Corporation, Baltimore, MD (US)
- Sponsoring Organization:
- FETC, USDOE Office of Energy Research (ER) (US)
- DOE Contract Number:
- FG02-95ER81968
- OSTI ID:
- 811205
- Report Number(s):
- DOE/ER/81968-1; DOE/ER/81968--Phase 1 Final; DOE/ER/81968--Phase II Final; KM0000000; TRN: US200311%%245
- Resource Relation:
- Other Information: 1998 International Joint Power Generation Conference, Baltimore, MD (US), August 23-26, 1998; PBD: 5 May 1999
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
36 MATERIALS SCIENCE
ACTIVATED CARBON
AIR HEATERS
CARBON ADDITIONS
CIRCULATING SYSTEMS
EFFICIENCY
FLUE GAS
FLUIDIZED BEDS
FLY ASH
GAS FLOW
MERCURY
MERCURY COMPOUNDS
PARTICLE SIZE
PARTICULATES
FOSSIL-FUEL POWER PLANTS
AIR POLLUTION CONTROL
POLLUTION CONTROL EQUIPMENT
FLOW RATE
EVAPORATION
SULFUR DIOXIDE
HYDROCHLORIC ACID
PERFORMANCE