Kinetics of activated carbon gasification and regeneration

Thesis/Dissertation · Tue Jan 01 00:00:00 EST 1985

OSTI ID:6120322

Cheng, A T.Y.

The kinetics of activated carbon oxidation and regeneration were studied using a thermal balance and a fluidized bed reactor. In the gasification experiments, the oxidation rate and the chemisorption rate were measured for several powdered activated carbons with surface areas of 500 to 2400 m/sup 2//g. Activation energies of adsorption and intrinsic adsorption rate constants were obtained from transient adsorption tests at 300 to 400/sup 0/C. The data fitted a second-order Langmuir adsorption isotherm, suggesting that the oxygen molecules dissociated on the carbon surface. In the regeneration experiments, the effects of substituted side groups on the pyrolysis and regeneration of eleven phenolic compounds were studied. It was found that the strongly adsorbed aromatic ring of a substituted phenol remained on the carbon surface while the side group and hydrogen atoms were lost in pyrolysis. The amount of residue formed was independent of the number and molecular weight of the side groups, and could be estimated by calculating an aromatic ratio. The residues from alkyl phenols were oxidized at rates up to 12 times that of a moderate surface area base carbon. The increase in rate was due to the formation of active sites. Halogens had no effects on the oxidation rate, but sodium catalyzed both the reaction of residue and the base carbon. Oxygenated side groups could cause excessive loss of residue during pyrolysis. The adsorption capacity of spent carbons could be mostly recovered by pyrolyzing the adsorbate. The residue could be removed by oxidation, but there was little change in adsorption capacity, and the efficiency of regeneration was less as the amount of carbon recovered decreased.

• Research Organization: Cornell Univ., Ithaca, NY (USA)
• OSTI ID: 6120322
• Resource Relation: Other Information: Thesis (Ph. D.)
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
ACTIVATED CARBON
OXIDATION
REGENERATION
COAL GASIFICATION
CHEMICAL REACTION KINETICS
ACTIVATION ENERGY
ADSORPTION ISOTHERMS
CHEMICAL REACTORS
CHEMISORPTION
FLUIDIZED BEDS
PHENOLS
PYROLYSIS
RESIDUES
SURFACE AREA
ADSORBENTS
AROMATICS
CARBON
CHEMICAL REACTIONS
DECOMPOSITION
ELEMENTS
ENERGY
GASIFICATION
HYDROXY COMPOUNDS
ISOTHERMS
KINETICS
NONMETALS
ORGANIC COMPOUNDS
REACTION KINETICS
SEPARATION PROCESSES
SORPTION
SURFACE PROPERTIES
THERMOCHEMICAL PROCESSES
010404* - Coal
Lignite
& Peat- Gasification
010500 - Coal
Lignite
& Peat- Products & By-Products