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