Kinetic studies for the removal of sulfur from low-BTU gasses using reduced iron-ore pellets
The use of commercially produced iron ore pellets as a sorbent for desulfurization of a simulated Low-Btu gas was investigated. Additionally, the use of the desulfurized gas for iron oxide reduction was examined. The temperatures employed were from 700 to 900/sup 0/C, and pressure varied from 1 to 5 atmospheres. In addition to the kinetic data collected, the structure of the raw, reduced, and sulfided samples was examined. Optical microscopy, SEM (PGT), and diffusion studies were used to characterize the structure of all these materials. The results of the reduction experiments show reduction to occur with a substantial amount of pore diffusion control and the iron formed to be rather dense within the grains. Reduction in these gas mixtures was found to be comparable to reduction by CO and found to benefit by increasing temperatures. The sulfidation reaction was found to occur on iron and to be controlled by pore diffusion through the FeS product layer. The rate of sulfidation was found to decay very quickly in the first minutes of reaction, due to the formation of this dense FeS phase. The effective diffusivity through this layer was found to be far lower than in the reduced material (Iron). The formation of this phase is likely the result of two factors, the chemical molar density differences between Fe and FeS and also the sintering observed in the FeS layer. The model developed to describe the sulfidation reaction uses the Stefan-Maxwell equations for multicomponent diffusion, due to the complex nature of the gas, and Knudsen diffusion is also taken into account.
- Research Organization:
- Carnegie-Mellon Univ., Pittsburgh, PA (USA)
- OSTI ID:
- 6107916
- Resource Relation:
- Other Information: Thesis (Ph. D.)
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
AIR POLLUTION CONTROL
CHEMICAL REACTION KINETICS
REMOVAL
SORPTION
SULFUR
IRON ORES
AIR POLLUTION
DIFFUSION
GASEOUS WASTES
MATHEMATICAL MODELS
OPTICAL MICROSCOPY
REDUCTION
CHEMICAL REACTIONS
CONTROL
ELEMENTS
KINETICS
MICROSCOPY
NONMETALS
ORES
POLLUTION
POLLUTION CONTROL
REACTION KINETICS
WASTES
500200* - Environment
Atmospheric- Chemicals Monitoring & Transport- (-1989)