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Heat Transfer Oils


Phillips 66® Heat Transfer Oils are high-quality straight or inhibited mineral oils developed for use in open and/or closed liquid-phase heat transfer systems. They have excellent thermal stability and provide excellent resistance to cracking and sludge formation for long service life. They are not recommended for use in vapor-phase heat transfer systems.

Features & Benefits

  • Excellent resistance to thermal breakdown at high temperatures
  • Excellent performance in both open and closed heat transfer systems
  • Long service life
  • Excellent deposit control
  • Low odor
  • Non-corrosive


  • Heat Transfer Oils 22, 32, 32/46 and 46 are recommended for use in closed, liquid-phase, forced circulation heat transfer systems equipped with expansion tanks and pressure relief valves, where the maximum bulk oil temperature does not exceed 550oF (288oC). Preventive measures should be taken to minimize oil oxidation by eliminating air from the system prior to bringing the oil up to operating temperature. The use of an inert gas, such as nitrogen, under positive pressure in the expansion tank is recommended at all times during operation. Under no circumstances should the hot oil come into contact with air.
  • Heat Transfer Oils 22, 32 and 46 also are recommended for use in open, liquidphase, forced circulation heat transfer systems where the maximum bulk oil temperature does not exceed 374oF (190oC).
  • Skin film temperature can be estimated at 50°F to 75°F above bulk oil temperature in properly designed and operating systems. If skin film temperatures rise higher than this, the service life of the oil may be shortened. Additionally sludge and coke may be deposited resulting in reduced efficiency of the system.
  • Some common heat transfer applications include:*Direct and indirect-fired hot oil heaters in asphalt plants*Hot corrugation and gluing*Dehydration*Molding and extrusion equipment*Plastic and wax coating equipment*Organic synthesis hot oil systems