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Technical Data Sheet
Therminol® 55 Heat Transfer Fluid

  • HTF - production of bioalcohol
  • HTF - production of biodiesel
  • Asphalt
  • Asphalt storage
  • Biomass - orc
  • Cement - waste heat recovery + orc
  • Gas to liquid (gtl)
  • Hot mix asphalt
  • Natural gas purification
  • Oil or gas processing
  • Polymer & plastic
  • Waste heat recover + orc
Key Attributes
  • Excellent Low Temperature Pumpability
  • Excellent resistance to fouling
  • Long Life

Product Description

Therminol 55 is a synthetic heat transfer fluid used in moderate-temperature applications. Therminol 55 fluid is designed for use in nonpressurized/low-pressure, indirect heating systems. It delivers efficient, dependable, uniform process heat with no need for high pressures.

Performance Benefits

  • 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 overspecify your fluid.
  • Excellent resistance to fouling— Because Therminol 55 is a synthetic fluid, it resists 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.
  • Excellent Low-Temperature Pumpability—Therminol 55 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 55, your heat transfer fluid system can start up quickly and easily.

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Typical Properties

PropertyTest MethodTypical Value, Units
Appearance Clear, yellow liquid
Composition Synthetic hydrocarbon mixture
Maximum bulk temperature 300 °C (570 °F)
Extended maximum use temperature 315 °C (600 °F)
Maximum film temperature 335 °C (635 °F)
Normal Boiling Point 351 °C (664 °F)
     @300 mm2/s (cSt) -8 °C (17 °F)
     @ 2000 mm2/s (cSt) -28 °C (-18 °F)
Flash Point 
     COCASTM D92177 °C (350 °F)
Autoignition TemperatureASTM E659343 °C (650 °F)
 DIN 51794366 °C (691 °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) 67 °C (152 °F)
     20 ft/s, 1-in. tube (6.096 m/s, 2.54-cm tube) 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) 24 °C (75 °F)
     20 ft/s, 1-in. tube (6.096 m/s, 2.54-cm tube) 11 °C (52 °F)
Heat of Vaporizationa 228 kJ/kg (98.1 Btu/lb)
Viscosity, Kinematic 
     @ 100°CASTM D 4453.52 cSt, mm2/s
     @ 40°CASTM D 44519 cSt, mm2/s
Liquid Density 
     @ 25°CASTM D 4052868 kg/m3 (7.25 lb/gal)
Molecular Weight (Average) 320
Pseudocritical temperature 512 °C (953 °F)
Pseudocritical pressure 13.2 bar (191 psia)
Pseudocritical density 258 kg/m3 (16.1 lb/ft3)
Copper CorrosionASTM D 130<<1a
Moisture Content, maximumASTM E-203150 ppm
Dielectric Constant 
     @ 23°CASTM D-9242.23

aat maximum use temperature

Properties reported here are typical of average lots. Eastman makes no representation that the material in any particular shipment will conform exactly to the values given.

Eastman and its marketing affiliates shall not be responsible for the use of this information, or of any product, method, or apparatus mentioned, and you must make your own determination of its suitability and completeness for your own use, for the protection of the environment, and for the health and safety of your employees and purchasers of your products. No warranty is made of the merchantability of fitness of any product, and nothing herein waives any of the Seller's conditions of sale.

3/23/2020 7:58:16 AM