THE EFFECT OF MINERAL SPECIES ON OIL SHALE CHAR COMBUSTION AND STEAM GASIFICATION (WATER-GAS SHIFT REACTION, CATALYSIS, THERMOGRAVIMETRIC ANALYSIS, ALKALI, ALKALINE EARTH OXIDES)

Six oil shale samples with differing mineral compositions were retorted identically and the resulting char was subjected to combusion kinetic studies using TGA techniques to determine what effect the various minerals which are present in the shale might have on the reaction rate. Three of the shales were also subjected to a steam gasification kinetic study and one shale ash was used to evaluate the water-gas shift reaction. The effects of mineral species on both char combustion and steam gasification rates were evaluated by selectively altering the mineral content. This was achieved by pretreating with a complex set of acid and water leaches as well as by thermal pretreatment. Combusion and steam gasification results are compared in terms of simple kinetic expressions and are discussed in the context of mineral species initially present during reaction.; Combustion was found to be first order with respect to both oxygen partial pressure and char remaining. A dynamic simulation of a TGA was developed to aid in extracting intrinsic chemical reaction rate data when gas-solid mass transfer was non-negligible. On the one Devonian shale, Michigan Antrim, the char combustion rate was successfully separated from the pyrite oxidation rate. Intrinsic combustion rate constants were found to vary from one shale to another by a factor of eight. Catalytic activity was attributed to alkali and alkaline earth oxides fomed by mineral carbonate decomposition of nahcolite and calcite which resulted in an order of magnitude increase in the combustion rates.; The steam gasification rates varied by a factor of five and followed the same Langmuir-Hinshelwood model typically used in the coal gasification literature. Product gases from steam gasification were analyzed and gave evidence of a rapid water-gas shift reaction which resulted in a hydrogen-rich mixture. Evidence of catalytic activity by calcium, potassium, magnesium and iron oxides was also found. The water-gas shift reaction over oil shale ash was found to follow Langmuir-Hinshelwood kinetics and was catalyzed by iron oxides.