Capacity Improvement of DHT Charge Heater (210-H-100)

Furnace Improvements (FIS) was employed by a refinery in Southeast of Indiana to carry out a capacity improvement study of DHT charge heater (210-H-100). It is a vertical cylindrical, natural draft heater. It has a convection section and a top mounted stack. The reactor charge heater was originally designed to process 10,500 BPD of distillate with a heat duty of 14 MMBtu/hr. The client wanted to increase the capacity of heater to 14,300 BPD charge rate.


Operating data analysis indicated the following:

  • The heater was over fired by 59% compared to design

  • The heater was often operated at high heat duty and excess air

  • The bridgewall temperature was 117°F higher than the design

  • The flue gas temperature leaving convection coil was 179°F higher than the design

  • The firebox design was very tight as it was operated at high volumetric heat release

  • A tube leakage occurred in the convection section due to creep damage and sulfidation corrosion

FIS designed the heater for a process duty of 22.5 MMBtu/hr and following modifications were done in the heater:

  • Extended radiant section height

  • Provided new radiant coils of increased size and tube length

  • Provided new wider convection section with higher size tubes to decrease the coil pressure drop

  • Upgraded tube metallurgy to SS 347- More resistance to sulfidation corrosion due to higher chrome content

  • Installed a new refractory lined stack with a new manual operated damper

  • Increased the number of burners from 3 to 4 using FIS patented Inclined Firing Technology to ensure there was no flame impingement

  • One self-inspiriting pilot burner was provided for each burner

FIS scope of services included design, engineering, fabrication, Supply and erection activities of DHT charge heater. The capacity of the heater was enhanced by 36% by adopting above scheme.


The heater was successfully commissioned in October 2014.