Chemisorption, reaction and desorption studies of coal chars in steam, oxygen and carbon dioxide. Final report, January 1986-December 1989

Technical Report · Sat Sep 01 00:00:00 EDT 1990

OSTI ID:6213660

Radovic, L R; Lizzio, A A; Jiang, H

The use of a transient kinetics (TK) technique allowed a direct measurement of reactive surface area (RSA) for chars gasified in both CO{sub 2} and O{sub 2}, i.e., gasification rates normalized with respect to RSA were essentially constant over the entire conversion range. A temperature-programmed desorption (TPD) technique was also used to determine the amount of reactive surface intermediate formed on the chars during gasification in CO{sub 2} and O{sub 2}; the results were in good agreement with those obtained by TK. In addition, TPD allowed an important distinction to be made between the stable C-O complexes and reactive C(O) intermediates residing on the char surface during gasification in CO{sub 2} and O{sub 2}. The application of the two independent but complementary techniques provided a satisfactory quantitative understanding of char reactivity variations with conversion in CO{sub 2} and O{sub 2}. Both techniques possess the unique capability of separately determining the reaction rate constant (site reactivity or turnover frequency) and the number of active sites participating in the reaction (RSA). A comparison of turnover frequencies for different chars gasified in 1 atm CO{sub 2} suggested that char gasification may be a structure sensitive reaction. The concept of reactive surface area was also used to achieve a better quantitative understanding of catalyzed char reactivity variations with conversion in carbon dioxide.

• Research Organization: Pennsylvania State Univ., University Park, PA (USA). Dept. of Materials Science and Engineering
• OSTI ID: 6213660
• Report Number(s): PB-91-130252/XAB; CNN: GRI-5086-260-1419
• Resource Relation: Other Information: See also PB--88-205885
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
CHARS
SURFACE PROPERTIES
COAL GASIFICATION
CHEMICAL REACTION KINETICS
ACTIVATION ENERGY
CARBON DIOXIDE
CATALYTIC EFFECTS
DESORPTION
OXYGEN
PROGRESS REPORT
REACTION INTERMEDIATES
STEAM
SURFACE AREA
TEMPERATURE CONTROL
TRANSIENTS
CARBON COMPOUNDS
CARBON OXIDES
CHALCOGENIDES
CONTROL
DOCUMENT TYPES
ELEMENTS
ENERGY
GASIFICATION
KINETICS
NONMETALS
OXIDES
OXYGEN COMPOUNDS
PYROLYSIS PRODUCTS
REACTION KINETICS
THERMOCHEMICAL PROCESSES
010404* - Coal
Lignite
& Peat- Gasification