A laboratory-scale Circulating Fluidized-Bed Reactor (CFBR) has been selected to best overcome the tendency for caking coals to agglomerate during the mild gasification. Several characteristics make the CFBR unit attractive for this use. These include the capabilities to use a high velocity fluidization, dilute solid gas stream, recycle solids, high solid throughputs, and to maintain an inventory of inert solids. A cold-flow CFBR unit has been built for studying the dynamics of particle flow within the reactor. Limestone, sand, and Nylon BB's have been chosen to characterize this unit. The optimal operation has been predicted for Pittsburgh No. 8 bituminous and Montana Rosebud subbituminous coal using the data from the cold-flow model. The scope of these studies is to present some of the reactor's design considerations and to describe the reactor. 18 refs., 12 figs., 7 tabs.