Adsorption of sulfur dioxide and reduction of sulfate on alumina and alkali-alumina at high temperature

Thesis/Dissertation · Thu Jan 01 04:00:00 EST 1987

OSTI ID:5946470

Edelstein, S

Several interrelated problems in connection with the treatment of sulfur dioxide at temperatures between 700 and 800 C were studied. The interaction of SO/sub 2/ with Al/sub 2/O/sub 3/ was studied experimentally using B.E.T., thermogravimetry and temperature-programmed desorption. Adsorption takes place through a wide range of binding energies, with some SO/sub 2/ adsorbing irreversibly at temperatures below 800 C. The amount adsorbed depends on the surface history and thermal treatment. An adsorption isotherm based on a bimodal energy distribution provides an adequate description of the equilibrium process. The chemical composition, sulfation and regeneration of an alkali-alumina sorbent for sulfur dioxide were studied using thermogravimetry, gas chromatography, and x-ray photoelectron spectroscopy. The active sorbent consists of a thin layer of sodium and lithium aluminates supported on alumina. The rate of sulfation is proportional to the SO/sub 2/ concentration in the gas, up to (SO/sub 2/) ca 5000 ppm. The activation energy of the sulfation is E = 21.6 kcal/mole. The sulfated sorbent was regenerated by reduction with CO at 700-800 C. Sulfur removal from the sorbent and distribution gaseous products were measured at different alkali loadings, temperatures and CO concentrations. The reduction takes place in two consecutive stages through a complex reaction network in which the alumina support plays a decisive role, both as a reactant and as a catalyst. A simplified reaction network is used as a basis for a kinetic model that provides an adequate description of the reduction process at moderate sorbent loadings.

• Research Organization: California Inst. of Tech., Pasadena (USA)
• OSTI ID: 5946470
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
010800 -- Coal
Lignite
& Peat-- Waste Management
500200* -- Environment
Atmospheric-- Chemicals Monitoring & Transport-- (-1989)
54 ENVIRONMENTAL SCIENCES
ACTIVATION ENERGY
ADSORPTION
ADSORPTION ISOTHERMS
ALKALI METAL COMPOUNDS
ALUMINATES
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CHALCOGENIDES
CHEMICAL ANALYSIS
CHEMICAL COMPOSITION
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
CHROMATOGRAPHY
DESORPTION
ELECTRON SPECTROSCOPY
ELEMENTS
ENERGY
EQUATIONS
GAS CHROMATOGRAPHY
GRAVIMETRIC ANALYSIS
ISOTHERMS
KINETIC EQUATIONS
KINETICS
LITHIUM COMPOUNDS
MATHEMATICAL MODELS
NONMETALS
OXIDES
OXYGEN COMPOUNDS
PHOTOELECTRON SPECTROSCOPY
QUANTITATIVE CHEMICAL ANALYSIS
QUANTITY RATIO
REACTION KINETICS
REDUCTION
REGENERATION
REMOVAL
SEPARATION PROCESSES
SODIUM COMPOUNDS
SORPTION
SORPTIVE PROPERTIES
SPECTROSCOPY
SULFIDATION
SULFUR
SULFUR COMPOUNDS
SULFUR DIOXIDE
SULFUR OXIDES
SURFACE PROPERTIES
TEMPERATURE DEPENDENCE
THERMAL ANALYSIS
THERMAL GRAVIMETRIC ANALYSIS
X-RAY SPECTROSCOPY