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Show the rest of the kiln. The bricks were being lost in the first few feet of the kiln where the burner was located and the waste entered the kiln. Apparently, expansion/contraction of the bricks allowed fine sand/solid particles to enter between the top layer of fire brick and the underlying insulating brick which eventually caused the bricks to break loose. The problem was rectified by replacing the first few feet of brick in the kiln with a castable anchored to the kiln shell with steel and refractory studs. The incinerator was originally designed for incinerating shredded PCB capacitors in which case heavy solids carry over from the kiln to the downstream equipment was not expected. When the kiln was incinerating 3 cubic yards/hr of contaminated solids, a heavy carry-over of fine solids from the kiln exit gas into the secondary combustor and downstream equipment was observed. Table 3 presents the particle size distribution of the solid samples taken at various locations. Dual cyclone separators were installed between the kiln and the secondary combustor which took care of most of the solids carry over problems. During initial start-up, clogging of boiler tubes with solid/chemical deposit and on outlet end of the tube sheet was noticed. Figure 5 and Figure 6 illustrate the point. Recirculated quench water containing solids struck the rear end tube sheet and formed a solid coating. Recirculated water which was acidic at times also caused corrosion of the tube sheet. All the quench sprays were moved from quench elbow to the quench sump box. Also, Ph of the quench water was maintained close to neutral by caustic injection. Since these modification were completed, the system has operated -11- |