Three operational tests were performed in the PDU. The operation of the two-stage cyclone system was verified; overall fines collection efficiency ranged from 80 to 90% on the Pittsburgh coal. This compares favorably with the 65% efficiency experienced with the single cyclone. Two tests were conducted in the cold flow scale-up facility (CFSF) to determine the operability of the cyclone, as well as to obtain data on jet penetration, bubble diameter and bubble frequency. A matrix of nine set points was completed, each of which was filmed with a high-speed movie camera. Following the test, the films were analyzed with a motion analyzer. The design of the high temperature unit was completed and the necessary materials and instrumentation were ordered. Because of modeling and design needs, the extent to which solids mix and/or deviate from the ideal flow patterns in different regions within the fluidized-bed gasifier was investigated. Of particular interest was the history of solids injected into the reactor by means of a gas-solid two-phase jet. To study the history of injected solids, solid tracer particles were fed pneumatically through a jet into a steady fluidized-bed. The experiments were performed at ambient temperature and atmospheric pressure. The preliminary data obtained at the CFSF during test TPM002-1 were analyzed for jet penetration depth, bubble diameter, and bubble frequency. The jet penetration correlation developed at Westinghouse successfully correlated the data to within 25%, far superior to the most quoted correlations available in the literature, which showed deviations from 114 to 506%.