Kinetic and Structural Studies of Regeneration of Sulfided Dolomite in Carbon Dioxide Ii the Cyclic Regeneration

Chou, Chia-Ling

doi:10.1080/00986448408940157

Cited by 2 publications

(2 citation statements)

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“…Because of their low cost, calcium oxide and the related calcium carbonate and dolomite were early favorites (Ruth et al, 1972;Freund, 1984 and Roache, 1984). These sorbents could be used once through or could be regnerated by H20-CO2 or by 0 2 to the carbonate or oxide forms (Kearns et al, 1976; Chou and Li, 1984; Sommer et al, 1984). The regeneration offgas is a relatively dilute stream containing H2S or SO2 that must be processed further for final sulfur disposal or conversion to elemental sulfur or sulfuric acid.…”

Section: Jet Propulsion Laboratory Pasadena California 91 109mentioning

confidence: 99%

Reduction, sulfidation, and regeneration of mixed iron-aluminum oxide sorbents

Patrick¹,

Gavalas²,

Sharma³

1993

Ind. Eng. Chem. Res.

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The reduction and sulfidation of Fe203 and Fe203-Al203 sorbents were investigated by thermogravimetric analysis (TGA). Mixed iron-aluminum oxides were reduced more slowly and by a more complex mechanism than pure iron oxide. Several phases that were responsible for this difference were identified by temperature-programmed reduction (TPR), X-ray diffraction (XRD), BET surface area (BET), and scanning electron microscopy (SEM). Sulfidation of reduced sorbents in the TGA at 600 "C produced two crystalline phases: high-temperature, hexagonal pyrrhotite (Fel,S), and unreacted FeA1204. The reaction of the pure and mixed oxide with a mixture of H2S-H2-H20-N2 was studied in a tubular microreactor to evaluate the performance of these materials as hightemperature H2S sorbents. At 650 "C the mixed oxide yielded considerably lower prebreakthrough outlet H2S levels than the pure iron oxide. Regeneration in pure SO2 and SOZ-air mixtures of sulfided samples resulted in complete conversion of iron sulfide to iron oxide and quantitative recovery of elemental sulfur.

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Section: Jet Propulsion Laboratory Pasadena California 91 109mentioning

confidence: 99%

Reduction, sulfidation, and regeneration of mixed iron-aluminum oxide sorbents

Patrick¹,

Gavalas²,

Sharma³

1993

Ind. Eng. Chem. Res.

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“…A reaction system of CaS−O 2 −CO 2 has been studied by Qiu et al Thus, for instance, when CaS was reacted with a mixture of 4% O 2 /80% CO 2 /16% N 2 at 850 °C, it was found that the solid products were CaSO 4 and CaCO 3 , with the conversion being 42% and 6% in 150 min, respectively. Regeneration of sulfided dolomite has also been studied using various mixtures of O 2 /CO 2 and H 2 O. , More recently, Qiu et al have shown that CO 2 can convert CaS, under both pressurized and atmospheric conditions over a wide range of temperatures, to CaO, CaSO 4 , and CaCO 3 . However, the exact mechanism by which these transformations occur is far from clear, although it is possible to write a series of balanced equations in which CaS is converted to these products, such as: …”

Section: Introductionmentioning

confidence: 99%

CaS Oxidation by Reaction with CO₂ and H₂O

2003

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Calcium sulfide is an undesirable product from both FBC and topping cycle gasifiers. Unfortunately, its direct oxidation in a FBC environment is made difficult due to the fact that unreacted CaS is protected from further reaction with O 2 by formation of a CaSO 4 shell. In previous work it was often implied that oxidation of CaS occurred solely by reaction with O 2 . However, this study shows that CO 2 can be an effective oxidant for CaS at temperatures above 600°C. Furthermore, it appears that the principal gas-phase products are SO 2 and CO, and direct attempts to measure COS using mass spectrometry suggest that its formation is negligible. Somewhat surprisingly, SO 2 /CO molar ratios are in the range of 0.4 to 0.5, which is problematic, if the dominant reaction is CaS + 3CO 2 d CaO + 3CO + SO 2 , unless CO 2 is reacting to form elemental carbon, which appears unlikely, or side reactions occur, leading to a variety of gaseous products. These results also suggest that CO itself has no significant part in the oxidation process at least up to 850°C or more. Reaction with H 2 O also begins above 600°C, but it is a much less effective oxidant, and experiments with CO 2 /H 2 O further support the idea that CO 2 is the more important oxidant and might be used to destroy CaS from topping cycle gasifiers.

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Kinetic and Structural Studies of Regeneration of Sulfided Dolomite in Carbon Dioxide Ii the Cyclic Regeneration

Cited by 2 publications

References 6 publications

Reduction, sulfidation, and regeneration of mixed iron-aluminum oxide sorbents

Reduction, sulfidation, and regeneration of mixed iron-aluminum oxide sorbents

CaS Oxidation by Reaction with CO₂ and H₂O

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Kinetic and Structural Studies of Regeneration of Sulfided Dolomite in Carbon Dioxide Ii the Cyclic Regeneration

Cited by 2 publications

References 6 publications

Reduction, sulfidation, and regeneration of mixed iron-aluminum oxide sorbents

Reduction, sulfidation, and regeneration of mixed iron-aluminum oxide sorbents

CaS Oxidation by Reaction with CO2 and H2O

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CaS Oxidation by Reaction with CO₂ and H₂O