Oil shale project large retort run summary run L-3

L-3 was a combustion experiment in the 6.0 Mg retort conducted on May 7-12, 1979. Perhaps the most important conclusion is the high yield (83% of FA) that was achieved using a broad particle size distribution (-30.5 cm, +0.001 cm) with 15 to 20% of the shale larger than 15 cm. The nonuniform flow in the retort was closely predicted by the changing shape of the steam front. Steam front measurements made after the run indicated that the flow distribution through the bed was little affected by the retorting and combustion processes. Therefore, use of the steam front as a diagnostic tool for pre-assessing bed characteristics appears promising. The technique of ignition by hot-gas-preheating worked satisfactorily. No oxygen was observed in the exit gas during the entire retort operation. The temperature of the retort front was controlled by the air flux; no run-away temperatures were encountered when making the step grade change from 18-36 gal/ton. The hydrogen concentration in the exit gas reached approximately 18% in the rich (36 gal/ton) shale at the bottom of the bed. This is the highest concentration we have seen in any of our retorting experiments. The offgas composition appears to provide a potential meansmore » for remotely monitoring transitions from one average shale grade to another in modified in-situ retorts. A factor-of-three change in the CO/CO/sub 2/ ratio was observed as the combustion front moved from the 18 gal/ton to 36 gal/ton shale; also, about a factor-of-two change occurred in the rate of production of CH/sub 4/, H/sub 2/ and CO.« less