Todd Davis, Brigham Young University
Engineering
Oil shale is a sedimentary rock containing about 10% oil hydrocarbons. The United States has about 4 trillion barrels of oil in large regions of Colorado, Utah, and Wyoming. The hydrocarbons can be extracted by heating the shale to about 1000 F. This requires excessive amounts of energy, making it difficult to extract more energy than is consumed. We are researching a method to reuse or recycle the thermal energy of the heated shale back into the whole process, increasing the efficiency. This method is analogous to co-current or counter-flow heat exchangers in fluid flow. We are currently researching counter-current flow. To accomplish this we designed our retort (high heat kiln) to move the oil shale through a series of baffles. As it flows, the shale is heated and the oil is extracted as it becomes a vapor. A vacuum pump extracts this energy rich vapor out of the retort where it is condensed into a liquid oil. Meanwhile, the heated inert rock of the shale is returned adjacent to the incoming cold shale (counter-current heat exchange). This proximity of heated shale to cold shale allows the thermal energy to be transferred. 80% of the sensible heat has been recovered in our research. As stated above, the whole mechanism for this process is a rotating retort (kiln). The retort is about a 1 meter in length and ½ a meter in diameter. The kiln, on its small scale, can process about 5 tons oil shale/day. This comes to be about 85 gal Oil/day or 1.5 barrels/day.