Solid refuse disposal apparatus

In apparatus for disposing of pelletized refuse by conversion to useful gaseous product and inert solid residue, including a vertical shaft with an upper end for pelletized refuse providing a drying zone in the top section and a thermal decomposition zone in the intermediate section thereof to form a pelletized refuse bed, a hearth beneath said shaft and in flow communication with the lower end of said shaft, means for feeding oxygen-containing gas into said hearth as a combustion zone, and a tap hole communicating with said hearth for discharging molten residue therefrom, the improvement comprising:

• (a) a hearth volume V (ft.sup.3) which is greater than that defined by the following equation:
• V=7.28.times.10.sup.2 G.sub.r D.sub.s.sup.2 /P.sub.g
• where
• G.sub.r =pelletized refuse maximum feed rate (lb. refuse/ft.sup.2 shaft minimum cross-sectional area/second),
• D.sub.s =shaft minimum equivalent diameter (ft) and
• P.sub.g =furnace pressure (psia).
• (b) an opening connection between the shaft and the hearth having minimum cross-sectional area between 0.044 and 1.0 times the shaft minimum cross-sectional area,
• (c) a multiplicity of tuyeres as the means for feeding oxygen-containing gas into the hearth, each positioned at circumferentially spaced locations in the upper part of the hearth adjacent to the shaft-hearth connection (b) which are less than 35% of the vertical distance from the shaft-hearth connection (b) mid-point to the hearth floor, with
• (d) said tuyeres inclined downwardly and away from the shaft-hearth connection (b) and directed so that said oxygen-containing gas does not impinge directly against said pelletized refuse bed.