As a preamble to combustion studies, the fluidization characteristics of heterogeneous auto fluff were investigated in a Plexiglas test facility which simulates the bench-scale combustion/agglomeration unit at the Institute of Gas Technology (IGT). The latter bench-scale unit (BSU) has a central jet burner, sloping grid, and classification zone to control the process of ash agglomeration. A solids feeder system was designed which could successfully feed the heterogeneous auto fluff at an appropriate uniform feed rate to sustain its combustion with an auxiliary fuel gas. During some of the tests, it was found that at least a part of the natural gas fed to the central jet burner and auto fluff volatiles burned above the bed surface. Venturi and grid gas velocities, hot zone and bed temperature levels, turbulence, and solids circulation are some of the important parameters that need to be considered for the formation and controlled growth of ash agglomerates. In order to establish the influence of operating parameters on the formation of ash agglomerates, the hot zone and bed temperatures and the venturi to grid flow ratios were varied in this work. It was found that operating the bed with venturi gas velocity around minimum spouting created better solids circulation and hot zone conditions for agglomerate growth. This was confirmed by run 2 when the bed did not clinker and the average bed particle size was much above that for the other two runs conducted implying agglomerate formation. Clinker refers to fused bed material that blocks gas flow and thereby prevents uniform fluidization.