Sulfur capture kinetics for second generation PFBC

Book · Sun Dec 31 04:00:00 EST 1995

OSTI ID:287965

Lin, S Y ^[1]; Suzuki, T; Aida, C; Horio, M ^[2]

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1. Nagoya Univ. (Japan). Dept. of Energy Engineering and Science
2. Tokyo Univ. of Agriculture and Technology, Koganei, Tokyo (Japan). Dept. of Chemical Engineering

Fluidized bed coal combustion/partial gasification combined cycle (topping cycle or second generation PFBC) has the potential to provide: high efficiency and efficient sulfur capture with limestone through the following two sulfur capture reactions: reaction 1--CaO + H{sub 2}S = CaS + H{sub 2}O, and reaction 2--CaCO{sub 3} + H{sub 2}S = CaS + H{sub 2}O + CO{sub 2}. To design a gasifier for topping cycle the kinetic information on sulfidation reactions is very important since they are supposed to be not so rapid. In this work attention was focused on the effect of inlet partial pressures of H{sub 2}S, CO{sub 2} and H{sub 2}O as well as the total pressure on the characteristics of the above two reactions. A newly constructed pressurized thermogravimetric analyzer and an atmospheric TGA were used to measure the sulfidation rate. For both reactions the initial rates appeared to be first order with respect to H{sub 2}S inlet partial pressure. H{sub 2}S was captured much more rapidly by CaO (fully calcined limestone) than by CaCO{sub 3} (limestone). Reaction 2 took place even when CO{sub 2} partial pressure was greater than P*{sub CO{sub 2}}, the equilibrium partial pressure of limestone calcination. However, sulfidation rate was decreased with increasing P{sub CO{sub 2}}/P*{sub CO{sub 2}}. Increased steam partial pressure decreased the initial rate of reaction 1 without changing the final conversion significantly, but decreased to a large extent both the initial reaction rate and final conversion of reaction 2. When total pressure was low, calcination and sulfidation occurred successively.

• OSTI ID: 287965
• Report Number(s): CONF-950522--; ISBN 0-7918-1305-3
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
CALCIUM CARBONATES
CALCIUM OXIDES
CALCIUM SULFIDES
CARBON DIOXIDE
CHARS
CHEMICAL REACTION KINETICS
COAL GASIFICATION
COMBINED-CYCLE POWER PLANTS
EXPERIMENTAL DATA
FLUIDIZED-BED COMBUSTION
GAS GENERATORS
HYDROGEN SULFIDES
SORBENT INJECTION PROCESSES
SULFIDATION
THERMAL GRAVIMETRIC ANALYSIS
WATER VAPOR