Reaching Us Home Multiple Hearth Furnaces Columbus, OH Two new multiple hearth furnaces burning municipal sludge in Columbus, Ohio developed structural and operational problems shortly after they were put into service.
Rabble arms stir the sludge in the furnace, moving the sludge to progressively hotter hearths.
In addition, refractory damage developed, bull gears showed signs of deterioration, exhaust duct dampers were binding, corrosion was evident in baffles, and fluidized bed incinerators malfunctioned. SGH was retained to investigate these problems and to recommend means to quickly restore the furnaces to operation. To solve the rabble arm problem, we investigated the materials used to fabricate the shafts and rabble arms. Also, we performed detailed analyses of the stresses and deformations induced in the sockets by the high temperatures in the furnace and the external forces created by the sludge stirring operation. Based on these studies, we determined the safe operational shaft torque for the interim period while new components were fabricated.