Therminol® SP Heat Transfer Fluid


Therminol SP is a synthetic heat transfer fluid used in moderate-temperature applications. Therminol SP fluid is designed for use in nonpressurized/low-pressure, indirect heating systems. It provides efficient, dependable, uniform process heat with no need for high pressures.

Performance Benefits

  • Excellent resistance to fouling— Therminol SP is a synthetic fluid, it prevents the effects of oxidation 10 times better than mineral oils, meaning less oxidation and solids formation. For systems without nitrogen inerting, the performance advantages are significant.
  • Long Life—You will get years of reliable, cost-effective performance, even when operating your system continuously at 300°C (570°F). This means you do not have to over-specify your fluid.
  • Excellent Low Temperature Pumpability—Therminol SP is still pumpable at –28°C (–18°F), compared to some mineral oils that will not pump at temperatures below –7°C (20°F). With Therminol SP, your heat transfer fluid system can start up quickly and easily.
  • Noncorrosive to metals– Commonly used in the construction of heat transfer systems.

Typical Properties

PropertyTest MethodTypical Value, Units
AppearanceClear yellow liquid
Composition Synthetic hydrocarbon mixture
Maximum bulk temperature300 °C (570 °F)
Extended maximum use temperature315 ºC (600 ºF)
Maximum Film Temperature335 °C (635 °F)
Normal Boiling Point351 °C (664 °F)
@ 300 mm2/s (cSt)
@ 2000 mm2/s (cSt)

-8 °C (17 °F)
-28 °C (-18 °F)
Autoignition TemperatureASTM E659
DIN 51794
343 °C (650 °F)
366 ºC (691 ºF)
Flash Point COCASTM D92177 °C (350 °F)
Pour PointISO 3016-54 °C (-65 °F)
Minimum liquid temperatures for fully developed turbulent flow (NRe > 10000)
10 ft/s, 1-in. tube (3.048 m/s, 2.54-cm tube)
20 ft/s, 1-in. tube (6.096 m/s, 2.54-cm tube)

67 °C (152 °F)
45 °C (114 °F)
Minimum liquid temperatures for transitional region flow, (NRe > 2000)
10 ft/s, 1-in. tube (3.048 m/s, 2.54-cm tube)
 20 ft/s, 1-in. tube (6.096 m/s, 2.54-cm tube)

24 °C (75 °F)
11 °C (52 °F)
Viscosity, Kinematic
@ 100ºC
@ 40ºC
ASTM D 445
ASTM D 445
3.52 cSt, mm2/s
19 cSt, mm2/s
Liquid Density @ 25ºCASTM D 4052868 kg/m3 (7.25 lb/gal)
Heat of Vaporizationa228 kJ/kg (98.1 Btu/lb)
Pseudocritical temperature512 °C (953 °F)
Pseudocritical pressure13.2 bar (191 psia)
Pseudocritical density258 kg/m3 (16.1 lb/ft3)
Molecular Weight (Average)320
Moisture Content, maximumASTM E-203150 ppm
Dielectric Constant @ 23°CASTM D-9242.23
Copper CorrosionASTM D 130<<1a
Properties reported here are typical of average lots.

Key Attributes

  • Excellent resistance to fouling
  • Excellent low temperature pumpability
  • Lasting life


  • htf – production of bioalcohol
  • htf – production of biodiesel
  • Asphalt
  • Asphalt storage
  • Biomass – orc
  • Cement – waste heat recovery + orc
  • Desalination
  • Gas to liquid (gtl)
  • Hot mix asphalt
  • Natural gas purification
  • Oil or gas processing
  • Oil recycling
  • Polymer & plastic
  • Waste heat recover + orc
  • Wood panels

Get it now