No. 4 Platformer Heater Efficiency Improvement and NOx Reduction (Split Flow)
FIS carried out a Platformer Heater Revamp Project in October 2002.
The four-cell UOP Reformer Heater was originally designed for a heat duty of 181.32 MMBtu/hr, in 1970. The heater was operating at 67% thermal efficiency. The refinery wanted to improve the efficiency of this heater and also reduce NOx emissions. They did not want to generate steam or preheat combustion air.
The refinery approached the original designers of the heater. They provided them with a conventional scheme to preheat the feed in the convection section. The scheme had four major drawbacks:
- Fluid pressure drop went up
- Required grade mounted stack
- Required large diameter piping
- Cost was very high
"The installation costs were half compared to that of the conventional series flow design. The job was completed in October 2002 and has been running without any problems."
FIS was contacted by the refinery and requested we develop an economical scheme for improving efficiency. FIS redesigned the convection sections with a “Split Flow Technology” scheme. In this scheme the feed was heated parallel in the convection and the radiant section. The pressure drop across the heater remained the same even at higher capacity, due to this parallel processing. The additional piping used was only half the size of manifolds, and the existing stacks were reused. This scheme was nearly half the cost of conventional revamp. For NOx emissions reduction, FIS evaluated different schemes and arrived at replacing the existing burners with Ultra Low NOx burners with internal flue gas recirculation.
FIS carried out the entire scope of activities from conceptualization to commissioning of this heater revamp. The heater was successfully commissioned in October 2002. After revamp, the thermal efficiency of this heater was increased from 66% to 87% and the NOx emissions were reduced to less than 0.035 lbs Btu. The client is very pleased with the heater performance and has decided to go ahead with a similar revamp of their second reforming furnace.