XRG Technologies recently completed the revamp of a large vertical cylinder (VC) crude heater, solving several operational problems while increasing efficiency from 78% to 91%.
Utilizing CFD modeling, XRG discovered that the existing double circle burner layout was causing flame clouds, hot spots on the tubes, and substantial outlet temperature imbalances between the different radiant passes limiting the furnace capacity. The hot spots caused radiant section tube creep in the heater and shorter run lengths between decoking.
XRG’s initial CFD analysis showed flame impingement on tubes (left) and the improvements after the revamp (right)
To increase the heater efficiency, XRG designed a balanced draft air preheat system to take advantage of the heat that was being lost out the stack. XRG engineers modeled the combustion inside the furnace and optimized the heat flux profile by replacing the fifteen existing natural draft burners with five new forced draft burners.
Previous Burner Arrangement New Burner Arrangement
Because the higher capacity burners operate with preheated combustion air, XRG worked with the burner manufacturer to produce optimal flame height and flux profile while meeting the stringent NOx requirements when operating on the refinery’s wide variety of fuels.
CFD by XRG of previous flame shape and absorbed flux (left) and new burner performance (right)
To take advantage of an already planned outage on the heater, XRG provided turn-key supply and installation of the equipment required to revamp the heater, including ID and FD fans, ductwork, dampers and air pre-heater. XRG utilized its 3D modeling capabilities to design flue gas and combustion air duct work that would fit into the tight existing space around the heater and ensure it could be easily installed during the short shutdown window.
XRG met all emissions, operational, efficiency and reliability goals for this VC Heater Revamp!