Analysis of carbon-oxygen reactions by use of a square-input response technique and {sup 18}O isotope
- Kyoto Univ. (Japan)
Carbon gasification reaction has been investigated for decades including the pioneering works of Walker and his co-workers, but its mechanism has not been completely elucidated. The concept of the active surface area (ASA) was proposed by them, and its importance has been recognized. However, since ASA was measured by O{sub 2} chemisorption at below 300{degrees}C where carbon loss through gasification is negligible, it does not reflect the actual gasification situation. To overcome this weak point, measurements of ASA in a batch reactor and the so-called transient kinetic (TK) method were proposed. Ahmed and Back successfully measured the chemisorbed oxygen during the gasification using a batch reactor, and proposed a new mechanistic sequence for carbon-oxygen reaction which stresses the importance of the reaction between the gaseous oxygen and the chemisorbed oxygen. Radovic et al. proposed the concept of the reactive surface area (RSA), and reported excellent proportionality between the CO{sub 2} gasification rate and the RSA estimated by the TK and the TPD methods. Kapteijn et al. showed that the TK method with labeled molecules is more powerful to examine the mechanism. They found the presence of two types of surface oxygen complexes which desorb at different rates. A Square-input response (SIR) method is applied to the carbon-oxygen reaction. This method allows the observation of transient changes on two step changes. This method has been successfully applied to the analysis of a coal char gasification.
- OSTI ID:
- 433104
- Report Number(s):
- CONF-960376-; ISSN 0569-3772; TRN: 97:000008-0025
- Journal Information:
- Preprints of Papers, American Chemical Society, Division of Fuel Chemistry, Vol. 41, Issue 1; Conference: Spring national meeting of the American Chemical Society (ACS), New Orleans, LA (United States), 24-28 Mar 1996; Other Information: PBD: 1996
- Country of Publication:
- United States
- Language:
- English
Similar Records
The concept of reactive surface area applied to uncatalyzed and catalyzed carbon (char) gasification in carbon dioxide and oxygen
Role of carbon active sites in the oxidation of coal chars