A fundamental gasification study has been made on a North Dakota lignite. A very wide range of char reactivities was obtained by varying pyrolysis conditions and pretreatment of the lignite. For the predominantly uncatalyzed gasification reaction, carbon active site concentration was shown to be a meaningful reactivity index for demineralized chars and for carbons of varying crystallinity. For raw lignite chars, it was shown that CaO is the predominant catalytic species responsible for their high gasification reactivities. Lignite char gasification should be regarded as a catalyzed gas-solid reaction with the catalyst dispersion being the relevant reactivity parameter. When rates are expressed as turnover frequencies, observed reactivity differences of as much as 200-fold are reduced to within one order of magnitude. The commonly observed phenomenon of coal char deactivation with increasing pyrolysis severity was correlated with decreases in carbon active surface area and catalyst dispersion.
|Original language||English (US)|
|Title of host publication||Unknown Host Publication Title|
|Publisher||Government Inst Inc|
|Number of pages||12|
|State||Published - Dec 1 1985|
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