Description |
A two-staged fluidized-bed reactor for the energy-efficient, thermal recovery of bitumen from Utah tar sands has been constructed. This reactor is a scaled-up version of an earlier system investigated at the University of Utah, and involves the use of three liquid-potassium heat pipes which thermally couple an upper pyrolysis bed with a lower combustion bed. The reactor has been studied to determine the effect of multiple heat pipes, increased feed rate, and longer duration run times. The process consists essentially of three steps. In the first step, mined and suitably sized tar sand, being fed into the reactor at a constant rate, is pyrolyzed at temperatures of 440C to above 500°C in an inert atmosphere to volatilize and partially crack most of the contained bitumen. The vaporized products of the pyrolysis section are condensed and coalesced to give a synthetic crude oil. In the second step, coked sand, formed as a by-product in the pyrolysis reactor, is combusted with air at tempe |