Automation of an in-situ combustion tube and study of the effect of clay on the in-situ combustion process

A fully automated in-situ combustion apparatus supported by a minicomputer was designed, constructed, and tested. Results obtained from four adiabatic dry combustion runs to investigate the effect of clay on crude oil combustion are reported. Sand mixtures of varying clay (kaolinite) content were saturated with crude oil and water. The fourth run was performed with amorphous silica powder in the sand mixture for comparison with clay results. The authors concluded that the large surface area of the clays was a major contributor to the fuel deposition process. However, different oxygen utilization efficiencies obtained from both types of sand mixtures indicated that mechanisms controlling the combustion reaction also depended on the composition of the porous matrix. A thermogravimetric analyzer (TGA) and a differential scanning calorimeter (DSC) were used to obtain kinetic data on the effects of kaolinite type clay on crude oil combustion. The addition of kaolinite clay or silica powder changed the shape of the crude oil TGA/DSC thermograms significantly, but sand had no effect. The major effect on DSC thermograms was a shifting of the large amount of heat produced from a higher to lower temperature range. Reduction of activation energy caused by the addition of kaolinite clay tomore » the crude oil indicates both catalytic and surface area effects on combustion/cracking reactions.« less