AUTO FLUFF COMBUSTION AND ASH AGGLOMERATE FORMATION STUDIES IN A FLUIDIZED-BED COMBUSTOR

As a preamble to combustion studies, the fluidization characteristics of heterogeneous auto fluff were investigated in a Plexiglas test faci lity which simulates the bench-scale combustion/agglomeration unit at the Institute of Gas Technology (IGT). The latter bench-scale unit (BS U) has a central jet burner, sloping grid, and classification zone to control the process of ash agglomeration. A solids feeder system was d esigned which could successfully feed the heterogeneous auto fluff at an appropriate uniform feed rate to sustain its combustion with an aux iliary 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 velociti es, hot zone and bed temperature levels, turbulence, and solids circul ation 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 t o grid flow ratios were varied in this work. It was found that operati ng the bed with venturi gas velocity around minimum spouting created b etter solids circulation and hot zone conditions for agglomerate growt h. This was confirmed by run 2 when the bed did not clinker and the av erage bed particle size was much above that for the other two runs con ducted implying agglomerate formation. Clinker refers to fused bed mat erial that blocks gas flow and thereby prevents uniform fluidization.