Mechanism of CaO sulfation in boiler limestone injection

Conference · Thu Jan 01 04:00:00 EST 1987 · Prepr. Pap., Am. Chem. Soc., Div. Fuel Chem.; (United States)

OSTI ID:5931189

Stouffer, M R; Yoon, H; Burke, F P

Pilot and industrial-scale tests of boiler limestone injection (BLI) have demonstrated flue gas SO/sub 2/ reductions of around 50% at sorbent utilization efficiencies of 15-20%. The objective of the laboratory research program described in this paper was to improve BLI sorbent utilization through an understanding of the limestone calcination and CaO sulfation reaction mechanisms. This paper describes the laboratory sulfation studies. The laboratory work used a differential reactor operated at 700-1000/degree/C and lab-produced calcines from limestones, dolomites, and hydrated limes, having particle sizes in a range applicable to BLI. The lab work determined the intrinsic sulfation reaction rate and rate-controlling steps over this temperature range. The intrinsic rate increased with the square of calcine surface area and was rate controlling only at temperatures below 800/degree/C. At the higher temperatures more applicable to BLI, the sulfation rate was limited by pore diffusion of SO/sub 2/ and pore plugging by the sulfate product. Therefore, the reaction rate and the saturated sorbent efficiency depended strongly on particle size and calcine pore structure. The lab data indicate that an optimum calcine pore structure can be obtained by appropriately evaluating sorbents, controlling calcination conditions and incorporating alkali additives in the sorbent.

• Research Organization: Consolidation Coal Company, Library, PA (USA)
• OSTI ID: 5931189
• Report Number(s): CONF-8708275-
• Conference Information: Journal Name: Prepr. Pap., Am. Chem. Soc., Div. Fuel Chem.; (United States) Journal Volume: 32:4
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
010800* -- Coal
Lignite
& Peat-- Waste Management
ADSORBENTS
ALKALINE EARTH METAL COMPOUNDS
CALCIUM COMPOUNDS
CALCIUM OXIDES
CARBONATE ROCKS
CHALCOGENIDES
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
DATA
DIFFUSION
EXPERIMENTAL DATA
HIGH TEMPERATURE
INFORMATION
INJECTION
INTAKE
KINETICS
LIMESTONE
NUMERICAL DATA
OXIDES
OXYGEN COMPOUNDS
PARTICLE SIZE
POROSITY
REACTION KINETICS
ROCKS
SEDIMENTARY ROCKS
SIZE
SULFATES
SULFUR COMPOUNDS
VERY HIGH TEMPERATURE