A conceptual design and cost estimate were developed for an integrated oil shale process plant based on fluidized-bed retorting of Colorado oil shale with lift pipe combustion of retorted shale. The present study incorporates an alternate design for the fluidized-bed retorting system, similar to the configuration employed in fluid catalytic cracking designs. The modified retort design, which employs fluidized bed combustion of retorted shale and pneumatic transport of hot solids, was factored into the base case integrated plant. As in the base case study, the alternate plant design has a nominal capacity of 50,000 barrels per operating day of syncrude product, derived from oil shale having a Fischer Assay of 30 gallons per ton. The plant scope reflects a grassroots facility which receives run-of-mine oil shale, delivers product oil to storage, and disposes of the processed spent shale. Estimated investment costs and annual operating costs for the alternate plant design were developed. In addition, a technical and economic assessment of the modified retorting design was made relative to the base case study. 9 refs., 7 figs., 30 tabs.