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Oil shale retorting: kinetics of the decomposition of carbonate minerals and subsequent reaction of CO/sub 2/ with char

Conference ·
OSTI ID:6743364

The kinetics of the decomposition of the major carbonate minerals and subsequent reaction of CO/sub 2/ with char in Colorado oil shale have been studied by nonisothermal methods. These experiments have been carried out using heating rates and CO/sub 2/ pressures expected during typical in situ combustion retorting. The mineral species studied include nahcolite dawsonite, dolomite (ankerite), and calcite. Activation energies and pre-exponential factors characterizing the decomposition rate constants for the above minerals are given; these engineering rate data are expressed in a form amenable for use in mathematical models of the retorting process. The kinetics for the important reaction of calcite with quartz in oil shale is also discussed. Rate constants are reported for the reaction of CO/sub 2/ with residual organic carbon (char) in the retorted oil shale. This reaction is shown to be coupled to mineral decomposition. Removal of the carbonate minerals causes the reactivity of the char to drop by more than an order of magnitude. A dependence of the reactivity on the heating rate of the char generation is also observed.

Research Organization:
California Univ., Livermore (USA). Lawrence Livermore Lab.
DOE Contract Number:
W-7405-ENG-48
OSTI ID:
6743364
Report Number(s):
UCRL-80545; CONF-780460-2
Country of Publication:
United States
Language:
English