Design of a Post-combustion chambre

A steel mill called on us to make the post-combustion chamber of their 160-tonne direct current furnace more reliable and to reduce the cost of using it. The production losses due to the high frequency of maintenance shutdowns were too high a cost. Their problems were:
  • Corrosion in the lower part by condensation of corrosive elements on the surface of the pipes during transient phases.
  • High local thermal loads (around 400kW/m2)
  • Normal general wear and tear by erosion
  • High maintenance costs: limited lifetime of the part + long intervention time for panel changes
  • Water flow distribution not adapted to the thermal loads of the room
Suggested solutions:
  • Diagnosis of the existing system: Delta Water measurement campaign and water pressures in order to map thermal loads and water supply conditions.
  • Adapted design: thermal and hydraulic studies (SolidWorks software), increase in volume (+40%), new post-combustion chamber made up of 3 superimposable monobloc elements allowing easy assembly/disassembly. All circuits equipped with PT100 probes with connection box.
  • Complete supply of the post-combustion chamber with access gangways: adjusted manufacturing, passage to the test bench in our facilities.
  • Follow-up after commissioning: use of temperature recordings and test bench passage to check the reliability of the equipment.
Noted improvements:
  • Simplification of assembly operations
  • Much easier to carry out maintenance operations
  • Very sharp reduction in power trips on the furnace; previously due to alarms on water temperatures at the outlet of circuits
  • Better consideration of thermal loads
  • Significant reduction in downtime

The main characteristics are:

  • Parallelepiped shape with a hopper
  • Swivel sleeve
  • Two “pre-quench” water injection canes on the upper part of the machine
  • Afterburner volume of 144m3
  • Dimensions: depth 2768mm x width 4530mm x height 11462mm (excluding hopper)