Capacity Improvement for Reactor Charge Heater
In 2005, Furnace Improvements Services (FIS) was employed by a refinery in East Texas to carry out a capacity improvement of the Reactor Charge Heater (80-H-01). Client wanted to increase the process heat duty from 30 MMBtu/hr to 37 MMBtu/hr. The maximum firing rate limitation was 54 MMBtu/hr.
This heater was originally built in 1965 as a natural draft all radiant heater. It was modified in 1980 to increase its thermal efficiency from 55% to 89% by adding a convection section for steam generation. However, the heater was operating at 85% efficiency.
FIS was solicited by the refinery to develop an economical scheme for increasing the capacity. FIS redesigned the heater with FIS patented Split Flow Technology. Split Flow Technology aims to improve the utilization of thermal energy for process heating. This design works very well to increase the capacity of fired heaters without increasing the process side pressure drop. This is achieved by splitting the process fluid into two parallel streams as- Main Stream and Split Stream. In Main Stream the fluid is heated in the radiant section. In Split Stream the fluid is heated in convection section. The two streams are then combined at the heater outlet.
Salient features of the revamped design are as follows:
Utilizing FIS patented Split Flow Technology, the process stream was split in two streams, 33% flow in the convection section and 67% flow in the radiant section
Total process duty of the heater was increased by 23%
Firing rate of the heater was well under the limitation of 54 MMBtu/hr
Reduction in average radiant heat flux
No radiant section modification – existing tubes and supports were reused
Shortest turn-around time