title: Shell Spher process
text: # Shell Spher process
  
  The Shell Spher process (Shell Pellet Heat Exchange Retorting) is an above ground fluidization bed retorting technology for shale oil extraction. It is classified as a hot recycled solids technology.
  
  Raw oil shale is crushed to a fine particles. Heat is transferred to oil shale by heat-carrying ceramic balls of size 6 to 8 millimetres (0.24 to 0.31 in). Raw oil shale is preheated in fluidized bed at the temperature of 600 °F (320 °C) in the case if oxygen is used as fluidizing medium, or at 650 °F (340 °C) if non-oxidizing gases are used. Heated ceramic balls fall then through the bed in counter-current direction. The preheated oil shale is further heated in the retorting vessel. The retorted spent shale is cooled in a fast-fluidized bed by the recirculated cool pellets from the preheater; while cooling the spent shale ceramic balls are heated by the spent shale.
  
  