Transient kinetics study of catalytic char gasification in carbon dioxide
- Pennsylvania State Univ., University Park, PA (United States). Dept. of Materials Science and Engineering
In this paper, the deactivation behavior of K, Ca, and Ni catalysts during carbon (char) gasification in CO{sub 2} is investigated. Correlations were sought between gasification rates and reactive surface areas (RSA) of the chars. In addition, the results allowed some speculation on recently proposed mechanisms of catalysis. An excellent correlation was found in the case of K catalysis, suggesting the rate-determining step in the overall mechanism to be the same as in the uncatalyzed reaction, i.e., desorption of the reactive C(O) intermediate. For the Ca-catalyzed reaction, the quality of the correlation depended on catalyst dispersion, suggesting that an additional process, besides the direct decomposition of the reactive C(O) intermediate, contributed to the transient evolution of CO (e.g., oxygen spillover). No correlation was found for Ni-catalyzed gasification; an oxygen-transfer mechanism is proposed to explain these findings. Mixed catalyst systems (Ca/K, K/Ni, Ca/Ni) were also studied. An excellent correlation between reactivity and RSA was observed in cases where the K-catalyzed reaction was dominant.
- OSTI ID:
- 7172293
- Journal Information:
- Industrial and Engineering Chemistry Research; (United States), Journal Name: Industrial and Engineering Chemistry Research; (United States) Vol. 30:8; ISSN IECRE; ISSN 0888-5885
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
010404* -- Coal
Lignite
& Peat-- Gasification
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201 -- Chemical & Physicochemical Properties
ALKALI METALS
ALKALINE EARTH METALS
CALCIUM
CATALYTIC CRACKING
CATALYTIC EFFECTS
CHARS
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
COAL GASIFICATION
CRACKING
DEACTIVATION
DECOMPOSITION
ELEMENTS
GASIFICATION
KINETICS
METALS
NICKEL
POTASSIUM
PYROLYSIS
PYROLYSIS PRODUCTS
REACTION KINETICS
THERMOCHEMICAL PROCESSES
TRANSITION ELEMENTS