Circulating Fluidized-Bed Boilers

B&W’s IR-CFB low maintenance design features:

• Two-stage particle collection requires less maintenance than hot cyclones:
  • Eliminates thick refractory linings
  • Subject to lower erosion and can be thermally cycled faster than thick refractory
  • U-beams capture and recycle solids at lower gas velocities
  • Multi-cyclone dust collector (MDC) with metallic cyclones operate at lower temperature
  • Air slides eliminate loop seals and loop seal blowers
  • No sootblowers are needed with lower gas velocity convection pass; fine solids clean the tubes
  • MDC storage hoppers offer independent heat transfer control and more operating flexibility
• Thin cooled refractory with higher stud density in furnace is a robust wall protector
• IR-CFB uses 1/10 the mass of refractory of a hot cyclone CFB
• Reduced diameter zone (RDZ) almost completely eliminates solids erosion of membrane wall at the transition section (solids flow obstructions from refractory and change in wall angle)
• Bubble caps minimize back sifting of bed solids and bubble cap erosion
• U-beams are contained in a water/steam-cooled enclosure eliminating hot expansion joints
• Open bottom design can handle tramp materials in feed