"The Gas-Flow retorting process is predicated upon simple solids handling equipment and high retorting capacity. It features gravity flow of shale and a cross-flow principle wherein the heating gases pass across the moving shale bed in contrast to countercurrent flow. One of the more important process variables of the Gas-Flow retort is the temperature of the recycle-gas stream entering the retort. Raising the inlet-gas temperature from 1,0500 to 1,350 F, decreased the amount of recycle gas required by one-third and increased the rate of retorting from 618 to 1,016 lb. shale/hr./sq. ft. bed area. The higher retorting rate indicated above is seven times as great as that normally attained in internal-combustion processes. Oil recoveries were 102 volume percent of the raw shale assay when the low inlet-gas temperature was used and dropped to 95 volume percent as the inlet-gas temperature was raised to 1,350 F. From 500 to 850 cubic feet of hydrogen per barrel of crude oil is available in the product gas stream for possible use in hydrogenating the crude shale oil or a distillate thereof. Varying the inlet-gas temperature over the range studied had no apparent effect on the properties of the crude oils produced."