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The physical and chemical processes that occur typically in and around an oil-sand fragment are examined experimentally when the fragment is suddenly introduced into a hot, low-uniform-velocity, gaseous oxidizing stream. With increasing temperature, three regimes were identified in the behavior of the fragments: volatilization, slow heterogeneous combustion, and combustion of the fuel as a diffusion flame. An expression for the oil mass removal with time is then suggested on the basis of a Fourier number for the fragment. Moreover, it is shown that autoignition occurred within the issuing volatiles at temperatures above 520° C.

Experiments have been performed on laminar diffusion flames of mixtures of water and hydrocarbon vapor of different compositions with the mole fractions of water ranging up to about 0.9. The soot emission from the flame decreased steadily with an increase in water concentration; concurrently, there was a progressive decrease in the maximum flame temperature. It is concluded that the reduction in sooting tendency of diffusion flames with water addition is mainly a thermal effect.