Fundamental studies of catalytic gasification: Quarterly report, January 1, 1987-March 31, 1987

Technical Report · Sun Mar 01 04:00:00 EST 1987

OSTI ID:6141548

Heinemann, H

The gasification of graphite by H/sub 2/O vapor, wet H/sub 2/ and wet O/sub 2/, catalyzed by a Ni/K mixture has been studied using controlled atmosphere electron microscopy (CAEM). In H/sub 2/O vapor the carbon consumption, between 550 and 1100 C, is catalyzed by an edge recession mode of attack in the (1120) direction, with no sign of deactivation. In wet H/sub 2/ both channeling and edge recession occur simultaneously. The activation energy obtained was equal to 30 +- 2 Kcal/mol. The catalyst deactivates above 1000 C, but can be regenerated by treating the sample in H/sub 2/O vapor at 600 C. In wet O/sub 2/, graphite is also gasified by edge recession, but no preferred direction was observed. The catalyst maintains its activity up to 1000 C, and an activation energy of 25 +- 2 Kcal/mol was obtained. These results show that the catalytic properties of the Ni/K mixture are superior to those of Ni and K alone due to a cooperative effect between the components. The kinetic properties of a catalyst derived from a mixture of KOH and Ni(NO/sub 3/)/sub 2/ for steam gasification of three chars are presented. H/sub 2/, CO/sub 2/ and small amounts of CO and CH/sub 4/ are the reaction products. The product distribution is controlled by the activation energies for formation of the gases. The activation energies for H/sub 2/ and CO/sub 2/ formation are 29 and 36 Kcal/mol respectively. The catalyst derived from the KOH/Ni(NO/sub 3/)/sub 2/ mixture has better catalytic properties, due to a cooperative effect between nickel and potassium, than catalyst derived by loading the components alone. The mixture has a higher activity and lower activation energies for H/sub 2/ and CO/sub 2/ production than KOH alone, and higher resistance to deactivation than Ni(NO/sub 3/)/sub 2/ alone. Since char and graphite gasification have the same activation energies, it is concluded that there is a common mechanism for their gasification catalyzed by the KOH/Ni(NO/sub 3/)/sub 2/ mixture. 31 refs., 18 figs., 3 tabs.

• Research Organization: Lawrence Berkeley Lab., CA (USA)
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 6141548
• Report Number(s): LBL-23147; ON: DE87013972
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
010404* -- Coal
Lignite
& Peat-- Gasification
ACTIVATION ENERGY
ALKALI METAL COMPOUNDS
CARBON
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON MONOXIDE
CARBON OXIDES
CATALYSTS
CATALYTIC EFFECTS
CHALCOGENIDES
CHARS
COAL GASIFICATION
DEACTIVATION
ELECTRON MICROSCOPY
ELEMENTAL MINERALS
ELEMENTS
ENERGY
GASIFICATION
GRAPHITE
HYDROGEN
METALS
MICROSCOPY
MINERALS
NICKEL
NONMETALS
OXIDES
OXYGEN
OXYGEN COMPOUNDS
PARTIAL PRESSURE
PERFORMANCE
POTASSIUM COMPOUNDS
PYROLYSIS PRODUCTS
STEAM
TEMPERATURE DEPENDENCE
THERMOCHEMICAL PROCESSES
TIME DEPENDENCE
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS