Two hot oil heaters are located in an enclosed building. Each heater has an output of 8 million Btu/hour. The building has space for a third heater if needed for future expansion.
The heaters have refractory lining enabling them to burn a variety of heavy fuels or waste oils, in addition to No. 2 diesel fuel. They have combination burners that also enable them to burn natural gas as an alternative fuel.
The two heaters heat thermal fluid that in turn carries the heat to all asphalt tanks, two fuel tanks, the polymer blending system, and a steam generator. Both heaters heat thermal fluid in the same circuit and are connected in parallel with each other.
The thermal fluid system fluid uses 24,000 gallons of Mobil Therm 603. It is circulated by a skid-mounted tri-plex pump system. Life of the thermal fluid is prolonged by a nitrogen system that minimizes oxidation by replacing air in the expansion tank with a blanket of nitrogen.
The need to operate both heaters depends on the heat load, which varies with operating conditions. Each heater has a burner turn-down ratio of 3 to 1. Combined operation of the two heaters provides a turn-down ratio of 6 to 1. Having two heaters also provides partial backup in case one heater is temporarily out of commission.