Sulfation of calcium based sorbents in a combustion environment

Thesis/Dissertation · Thu Jan 01 00:00:00 EST 1987

OSTI ID:5517516

Newton, G H

The capture of SO/sub 2/ by dry, calcium-based sorbents was examined in a three part research effort: (1) an experimental evaluation of sorbent materials under isothermal reaction conditions; (2) characterization of sulfation fundamentals through sulfation rate measurements with sized, precalcined sorbents and the development of a distributed pore sulfation model; and (3) experimental definition of reaction temperature effects and computer modeling of the simultaneous sintering and sulfation processes. The experimental sorbent evaluation examined calcitic and dolomitic carbonates and hydrates. High temperature, isothermal SO/sub 2/ capture data were obtained as a function of Ca/S molar ratio, temperature, and SO/sub 2/ concentration for each sorbent. SO/sub 2/ capture was found to be approximately linearly dependent on Ca/S ratio, relatively insensitive to SO/sub 2/ concentration above 2000 ppM, and a strong function of sorbent type. Time resolved sulfation data of sized, precalcined sorbents indicated that sulfation is initially rapid, but beyond approximately 300 ms the sulfation rate decreases dramatically. A distributed pore model, which viewed CaO particles as composed of nonintersecting, cylindrical pores with diameters determined from nitrogen porosimetry, particle boundary layer, pore, and CaSO/sub 4/ product layer diffusions in addition to the heterogeneous chemical reaction was developed. Temperature dependent sulfation data for precalcined sorbents suggest two types of sintering influence particle porosity: sintering associated with the combustion process and sintering promoted by the presence of sulfate ions in the particle crystal structure. Inclusion of both sintering mechanisms in the distributed pore model allowed predictions of the highest temperature experimental data from a variety of precalcines.

• Research Organization: Utah Univ., Salt Lake City (USA)
• OSTI ID: 5517516
• Resource Relation: Other Information: Thesis (Ph. D.)
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
CALCITE
SORPTIVE PROPERTIES
DOLOMITE
SULFUR DIOXIDE
ADSORPTION
MATHEMATICAL MODELS
POROSITY
TEMPERATURE EFFECTS
ALKALINE EARTH METAL COMPOUNDS
CALCIUM CARBONATES
CALCIUM COMPOUNDS
CARBON COMPOUNDS
CARBONATE MINERALS
CARBONATES
CHALCOGENIDES
MAGNESIUM CARBONATES
MAGNESIUM COMPOUNDS
MINERALS
OXIDES
OXYGEN COMPOUNDS
SORPTION
SULFUR COMPOUNDS
SULFUR OXIDES
SURFACE PROPERTIES
500200* - Environment
Atmospheric- Chemicals Monitoring & Transport- (-1989)