Elutriation and entrainment phenomena of an earlier Westinghouse ash agglomerating combustor/gasifier process development unit is discussed. The reactor was 0.508 m in inside diameter and 11.6 m in height and was operated at 1580 kPa and 955-1065°C during tests using coke breeze and char derived from different coals. Data from the process development unit were compared with an entrainment model.