Steam gasification of carbon solids catalyzed by a nickel-potassium mixed oxide: Kinetic and surface characterization studies

Technical Report · Thu Oct 01 04:00:00 EDT 1987

OSTI ID:5823632

Carrazza Duca, J

The main goal of this thesis is to evaluate and understand the catalytic properties of a nickel-potassium mixture for steam gasification of carbon solids. This goal pursued by carrying out kinetic and surface characterization studies, using both graphite and a coal-char as carbon substrates. The kinetic study on graphite gasification shows that the nickel-potassium mixture has distinct catalytic properties for this reaction, when compared with potassium-alone and nickel-alone catalysts. The mixture is active at relatively low temperatures (800 K) compared with the potassium-alone catalyst, and does not deactivate with time, contrary to the case of nickel alone. These properties are attributed to a cooperative effect between nickel and potassium. The performance of the nickel-potassium catalyst in a process of technological interest, such as the steam gasification of coal-chars, was also investigated. The results indicate that the mixture is a better catalyst for steam gasification of low ash chars, than both nickel-alone and potassium-alone catalysts. A temperature programmed desorption and X-ray photoelectron spectroscopy study on the adsorption of O/sub 2/, H/sub 2/O, CO and CO/sub 2/ on clean graphite is also presented. It is proposed that all four gases form the same type of oxygen containing surface species, after chemisorption. The most abundant surface species desorbs as CO between 1000 and 1300 K, and has been assigned to a semi-quinone functional group. This CO precursor can react with the adsorbing gas, and form a second species, that desorbs as CO/sub 2/ between 500 and 900 K. A surface lactone has been proposed as the CO/sub 2/ surface precursor.

• Research Organization: Lawrence Berkeley Lab., CA (USA)
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 5823632
• Report Number(s): LBL-24268; ON: DE88003857
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
010404* -- Coal
Lignite
& Peat-- Gasification
ACTIVATION ENERGY
ADSORPTION
ALKALI METAL COMPOUNDS
ARRHENIUS EQUATION
CARBON
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON MONOXIDE
CARBON OXIDES
CARBONACEOUS MATERIALS
CATALYSTS
CATALYTIC EFFECTS
CHALCOGENIDES
CHARS
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
CHEMISORPTION
COAL
COAL GASIFICATION
COMPARATIVE EVALUATIONS
DESORPTION
DISPERSIONS
ELECTRON MICROSCOPY
ELECTRON SPECTROSCOPY
ELEMENTAL MINERALS
ELEMENTS
ENERGY
ENERGY SOURCES
EQUATIONS
FOSSIL FUELS
FUELS
GASIFICATION
GRAPHITE
HYDROGEN COMPOUNDS
KINETICS
MATERIALS
MICROSCOPY
MINERALS
MIXTURES
NICKEL COMPOUNDS
NICKEL OXIDES
NONMETALS
OXIDES
OXYGEN
OXYGEN COMPOUNDS
PHOTOELECTRON SPECTROSCOPY
POTASSIUM COMPOUNDS
POTASSIUM OXIDES
PYROLYSIS PRODUCTS
REACTION KINETICS
SEPARATION PROCESSES
SORPTION
SORPTIVE PROPERTIES
SPECTROSCOPY
STEAM
SURFACE PROPERTIES
TEMPERATURE DEPENDENCE
THERMOCHEMICAL PROCESSES
TRANSITION ELEMENT COMPOUNDS
WATER