Analysis of the SO/sub 2/-lime reaction system: mathematical modeling and experimental studies with emphasis on stoker applications

Thesis/Dissertation · Tue Jan 01 00:00:00 EST 1985

OSTI ID:5491829

Silcox, G D

This study examines the application of the pulverized, dry limestone injection process to stoker-fired boilers using a comprehensive mathematical model of the SO/sub 2/-lime reaction in conjunction with a series of bench-scale experiments. The mathematical model was also used to assess the application of limestone injection for pulverized, coal-fired boilers. Model predictions and SO/sub 2/ capture data led to the conclusion that the best description of the reaction process was one incorporating an intrinsically zero-order chemical sulfation reaction serially with pore and product layer diffusion steps. Model predictions showed that sulfur capture increased linearly with increasing Ca/S molar ratio. The predicted apparent dependence on SO/sub 2/ concentration varied from zero- to first-order depending on particle size and reaction conditions. For time-temperature histories typical of boilers, the model demonstrated that the optimum limestone injection location is at the highest temperature at which sulfation is thermodynamically possible (ca. 2250/sup 0/F at 3000 ppm SO/sub 2/). Bench-scale experiments using a pulverized limestone sorbent showed that SO/sub 2/ capture increased roughly linearly with increasing molar Ca/S ratio. The effects of changes in SO/sub 2/ partial pressure were small. The introduction of cooling coils in the bed region of the test facility had no significant impact on SO/sub 2/ capture. Capture levels obtained with natural gas doped to 3000 ppm of SO/sub 2/ at Ca/S = 2 ranged from 25 to 30%. With high sulfur Illinois coal at Ca/S = 2 the capture was 35%. Comparisons of the model to the data showed good agreement at all conditions.

• Research Organization: Utah Univ., Salt Lake City (USA)
• OSTI ID: 5491829
• Resource Relation: Other Information: Thesis (Ph. D.)
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
BOILERS
DESULFURIZATION
COAL
COMBUSTION
LIMESTONE
CHEMICAL REACTIONS
SULFUR DIOXIDE
BENCH-SCALE EXPERIMENTS
CHEMICAL REACTION KINETICS
EFFICIENCY
MATHEMATICAL MODELS
PARTICLE SIZE
PRESSURE DEPENDENCE
PULVERIZED FUELS
QUANTITY RATIO
SORPTIVE PROPERTIES
CARBONACEOUS MATERIALS
CARBONATE ROCKS
CHALCOGENIDES
ENERGY SOURCES
FOSSIL FUELS
FUELS
KINETICS
MATERIALS
OXIDATION
OXIDES
OXYGEN COMPOUNDS
REACTION KINETICS
ROCKS
SEDIMENTARY ROCKS
SIZE
SULFUR COMPOUNDS
SULFUR OXIDES
SURFACE PROPERTIES
THERMOCHEMICAL PROCESSES
010800* - Coal
Lignite
& Peat- Waste Management
014000 - Coal
Lignite
& Peat- Combustion