Marathon Petroleum | Garyville Refinery | Garyville, La.


In 2007, Marathon embarked on the Garyville Major Expansion project (GME), one of the largest refinery expansions in U.S. history. The GME project was conceived as a way to enhance the refinery's ability to adjust feed-stocks and yields, and to make rapid production changes according to market shifts. The GME increased Garyville's production capacity by 180,000 barrels to 436,000 per day, making it the fourth largest refinery in the country.

OnQuest was retained by Marathon to design and build nine separate heaters for Garyville. Our scope including engineering and installing the world's largest heater.


During the course of the GME, OnQuest was retained by Marathon to design and construct nine heaters, including:

  • One 700-million BTU/hr combined three-cell platfomer heater, including three radiant and convection cells with common flue-gas ducts
  • One 230-million BTU/hr delayed coker heater, with included common flue-gas ducts, a combustion air preheater, an SCR system, and forced- and induced-draft fans
  • One 40-million BTU/hr reactor charge heater for the KHT unit, with one 60-million BTU/h stripper reboiler heater
  • Two 30-million BTU/hr reactor charge HCU heaters
  • One 180-million BTU/hr fractionator feed HCU heater
  • One 30-million BTU/hr reactor charge heater for the NHT heaters
  • One 40-million BTU/hr stripper reboiler heater for the NHT heaters


  • The three-cell platformer heater that OnQuest built and installed at Garyville is the largest heater ever designed.
  • OnQuest's updates helped further reduce NOx emissions at the facility; our HCU heaters reduced the pressure loss to 5 psi at 150,000 lb/h. The Garyville refinery is now one of the most efficient refineries in the U.S.