Debottlenecking options for a CDU furnace


  • A crude heater, designed for 30,000 barrels per day, of cabin type with 5Cr radiant and shock-row tubes and a carbon steel convection section


  • To define upgrade options for the furnace so as to allow the capacity of the crude distillation unit to be increased to around 40,000 bbl/day, as part of a refinery debottlenecking project


  • Definition of basic heater parameters by performing baseline simulations of design and of current operating conditions
  • Identification of likely limitations to operation at a higher process throughput
  • Proposition of upgrade options to overcome these limitations, with an analysis of the technical advantages and disadvantages of each
  • Level 1 life assessment of existing furnace tubes, under conditions pertinent to the favoured upgrade option


  • Six options were identified:
    - operate the furnace unmodified
    - extend the stack to increase draught
    - install a forced draught system
    - install an air preheat system with coupled I/D-F/D fans
    - install a process preheater furnace
    - install a twin furnace in parallel
  • Operation with the furnace unmodified would be the most economic option; installation of a process preheater would be the favoured upgrade
  • Life assessment indicated that tube replacement would be needed in around 5 years if the furnace were to be operated unmodified
  • Careful control of operating conditions would be required if the furnace were to be operated unmodified


  • Most cost-effective option defined, and associated advantages and disadvantages identified
  • Optimal balance between improved performance, component life and capital spend attained
  • Operational, inspection and maintenance requirements identified for successful achievement of the debottlenecking objective

Plant Integrity