Importance of active sites for char gasification in oxygen (air) and carbon dioxide. Annual report Oct 80-Sep 81

Technical Report · Thu Oct 01 00:00:00 EDT 1981

OSTI ID:5253682

Walker, Jr, P L; Jenkins, R G; Radovic, L R

The reactivities of chars, obtained by rapid and slow pyrolysis of raw and suitably pretreated North Dakota lignite under widely varying conditions of temperature, heating rate and residence time, have been measured using thermogravimetric analysis. The pretreatment involved coal demineralization, ion exchange with ammonium acetate, and subsequently ion exchange with calcium acetate. In order to preserve the structure of the chars obtained by rapid pyrolysis, air was used as the reactant at low temperatures in the range 250 to 450C. Small amounts of sample (1-2 mg) were used in order to eliminate the effects of non-isothermal behavior and interparticle diffusional limitations on the observed kinetics. Major reactivity differences were observed as a function of pyrolysis residence time and the type of coal pretreatment used. These differences cannot be accounted for if the reactivities are normalized with respect to the total (CO2) surface areas of the chars. Catalysis of gasification by highly dispersed calcium was shown to be the predominant factor responsible for the high reactivity of the lignite chars.

• Research Organization: Pennsylvania State Univ., University Park (USA)
• OSTI ID: 5253682
• Report Number(s): PB-82-180621
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
010404* -- Coal
Lignite
& Peat-- Gasification
ALKALINE EARTH METALS
BROWN COAL
CALCIUM
CARBONACEOUS MATERIALS
CATALYSIS
CHARS
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
COAL
COAL GASIFICATION
DECOMPOSITION
ELEMENTS
ENERGY SOURCES
FOSSIL FUELS
FUELS
GASIFICATION
ION EXCHANGE
KINETICS
LIGNITE
MATERIALS
METALS
PYROLYSIS
PYROLYSIS PRODUCTS
REACTION KINETICS
SURFACES
THERMOCHEMICAL PROCESSES