Cat Feed Hydrotreater Heater Performance Improvement & Low NOx Burners

CFHT heater is a natural draft vertical cylindrical furnace, with a horizontal overhead convection section. The convection section had been experiencing tube failures for many years. A client employed Furnace Improvements to review the design and operation of the CFHT Heater and requested to provide an improved design, which will eliminate tube failures in the convection section.

Furnace Improvements carried out a thorough analysis of the heater. The convection section had a very high heat flux leading to high skin temperatures and subsequent tube failures.

FIS designed the new convection section in one week. It not only solved tube failure problems, but also improved its performance. In the revamped convection section:

• Skin temperature was reduced from 740 to 675°F.
• Thermal Efficiency was improved from 79.5 % to 86%.
• Stack temperature was reduced from 764°F to 537°F.

CFHT Heater Convection Revamp

Parameter	Units	Before Revamp	After Revamp
Heat Duty	MMBtu/hr	16.70	16.70
Heat Release	MMBtu/hr	21.64	19.45
Skin Temp.	°F	740	675
Efficiency	%	79.57	85.87
Stack Temp.	°F	764	537

The project was successfully implemented in the last turnaround in June 2002.

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