Effect of grain size on the lime sulfation reaction

Conference · Sun Jan 01 04:00:00 EST 1984

OSTI ID:6917683

Marsh, D W; Ulrichson, D L

Reaction measurement made on CaO pellets, presintered for varying amounts of time, showed that the optimum reaction temperature increases with increased presintering time. Conversion data from unsintered pellets showed that the optimum reaction temperature also increases with increased initial porosity. In both cases, the increases in optimum temperature are caused by increases in the relative pore size, which is indicative of pore closure effects. A one-dimensional expanding grain model was developed and applied to the lime pellet sulfation data. The model accurately predicts an optimum initial grain size at any given reaction temperature. It also correctly predicts the upward effect of increased initial grain size on the optimum reaction temperature. The effect of an initial grain size distribution on the conversion-time predictions of the model were considered. The size distribution effects were not as important as the effect of the average initial grain size. For a reaction that is controlled by product layer diffusion, the model correctly predicts an increase in reaction rate from an increase in temperature. The model also predicts that for a reaction controlled by pore diffusion, a decrease in temperature is accompanied by an initial decrease and eventual increase in reaction rate.

• Research Organization: Ames Lab., IA (USA)
• DOE Contract Number: W-7405-ENG-82
• OSTI ID: 6917683
• Report Number(s): IS-M-510; CONF-8405154-7; ON: DE84015471
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
010402 -- Coal
Lignite
& Peat-- Purification & Upgrading
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ALKALINE EARTH METAL COMPOUNDS
CALCIUM COMPOUNDS
CALCIUM OXIDES
CHALCOGENIDES
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
CRYSTAL STRUCTURE
FABRICATION
GRAIN SIZE
KINETICS
MICROSTRUCTURE
OXIDES
OXYGEN COMPOUNDS
REACTION KINETICS
SINTERING
SIZE
SULFUR COMPOUNDS
SULFUR DIOXIDE
SULFUR OXIDES
TEMPERATURE DEPENDENCE
TIME DEPENDENCE
VERY HIGH TEMPERATURE