Regenerative process for desulfurization of high temperature combustion and fuel gases. Quarterly progress report No. 9, April 1--June 30, 1978
Thermodynamic calculations showed that all the calcium silicates are capable of sorption of SO/sub 2/ from coal combustion gases to meet the standard of 0.2 lb S/10/sup 6/ Btu at below 900/sup 0/C. Temperature limits for the di- and tricalcium silicates are higher than 900/sup 0/C. The silicates are thermodynamically more regenerative from their sulfated states than CaO. Kinetic studies were performed on sulfation and regeneration of various calcium silicate samples. Except for two samples, the silicates showed higher overall rates and, more important, higher capacities for sulfation, compared with CaO on a molar basis. The rates of regeneration of the silicates were much higher than that of CaO; more specifically, the rates of thermal decomposition of the sulfated mono- and dicalcium silicates were about 15 times higher than that of the CaSO/sub 4/, which indicated the relative bond strengths between SO/sub 3/ and the sorbents. X-ray diffraction and infrared analyses of the reaction products are discussed. Rates of sulfation and regeneration were measured for SiO/sub 2/-supported CaO. CaO was precipitated on a high surface area granular SiO/sub 2/ from aqueous solutions of calcium salts followed by a heat treatment. Compared with the Al/sub 2/O/sub 3/-supported CaO, which were actually calcium aluminates on the surface of Al/sub 2/O/sub 3/, the sulfation rates were about the same, but the regeneration rates were definitely higher for the SiO/sub 2/-supported sample. A kinetic study has been performed of the apparent solid--solid reaction between CaS and CaSO/sub 4/ with a rotary kiln reactor. The experimental conditions were within the range for regeneration of the lime-based sorbents for fluidized-bed combustion. The kinetic parameters of the chemical reaction extracted from the data compared favorably with those obtained directly and independently with a fixed-bed thermogravimetric reactor. Promising results were obtained on the utilization of coal ash as a binder for the fine-sized sorbents.
- Research Organization:
- Brookhaven National Lab. (BNL), Upton, NY (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- EY-76-C-02-0016
- OSTI ID:
- 6541892
- Report Number(s):
- BNL-50891
- Country of Publication:
- United States
- Language:
- English
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Calcium silicates: a new class of highly regenerative sorbents for hot gas desulfurization
Calcium silicates: a new class of highly regenerative sorbents for hot gas desulphurization
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20 FOSSIL-FUELED POWER PLANTS
FLUE GAS
DESULFURIZATION
FUEL GAS
SULFUR
REMOVAL
ADSORPTION
CALCIUM OXIDES
CALCIUM SILICATES
CHEMICAL REACTIONS
COAL
FLUIDIZED-BED COMBUSTION
REGENERATION
SORPTIVE PROPERTIES
SULFUR DIOXIDE
THERMODYNAMICS
ALKALINE EARTH METAL COMPOUNDS
CALCIUM COMPOUNDS
CARBONACEOUS MATERIALS
CHALCOGENIDES
COMBUSTION
ELEMENTS
ENERGY SOURCES
FLUIDS
FOSSIL FUELS
FUELS
GAS FUELS
GASEOUS WASTES
GASES
NONMETALS
OXIDATION
OXIDES
OXYGEN COMPOUNDS
SILICATES
SILICON COMPOUNDS
SORPTION
SULFUR COMPOUNDS
SULFUR OXIDES
SURFACE PROPERTIES
THERMOCHEMICAL PROCESSES
WASTES
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