:: Boilers &Thermic Fluid Heaters --- ID :: 18661
SYNTHETIC SIGMA T H E R M® -K
Can we use Synthetic Sigma Therm - K for top up purpose?

By Kiran Thakar // Petrobazaar // 10th June, 2021.

About The Writer

Mr. Kiran Thakar is an Govt of India Accredited Energy Auditor and a Master Trainer- govt of India skill development program, a Technical  Trainer in the field of process heating technology, with four decades of professional working experience. Extensively worked in the field of green fuels and tech, with biomass fuels as special interest.


What is Mineral Oil Based Heat Transfer Fluid / Thermic Fluid?


In the Petroleum refinery crude oil goes through various refining processes like Distillation, Cracking, Isomerisation, Hydrogenation etc. 


In the distillation process crude oil is heated and at different temperatures different petroleum products are available like – LPG, Aviation Fuel, Petrol, SKO, Diesel, Lubricant Base Oil, LDO, FO, Asphaltene etc. 

This separation is purely on the basis of their boiling ranges. It means whatever may be the chemical structure (Paraffinic, Naphthenic, etc) and if it boils within a certain temperature range it will be classified as a certain petroleum product. This fundamental is also applicable for the lubrication base oil. It contains different class of chemistry with different structures like linear and branched chain with saturated and unsaturated carbons. 


A particular boiling range petroleum refinery cut is being used as base oil for mineral based thermic fluid. Since source of raw material is mineral oil ( Petroleum Crude ) it is called Mineral based thermic fluid. 


Sigma T H E R M®- K- Synthetic Heat Transfer Fluid / Thermic Fluid 


Since molecule of sigma T H E R M®- K is made by “Synthesis” process, it is called as synthetic oil. A particular short length of Straight and Saturated Chain of Alkyl group is been reacted with particular Aromatic to produce Alkyl Substituted Aromatic. Alkyl Substituted Aromatics are a base oil of sigma T H E R M®- K 


It has a definite chemical structure and very narrow range of boiling. 


Compatibility Testing : We have conducted several test on various mineral based heat transfer fluids taken from running system with fresh sigma T H E R M®- K. All results say that both products are compatible with each other. At present there are so many industries using sigma T H E R M®- K for top up purpose in the system filled with various brands of mineral oil based heat transfer fluids. 


Merits of sigma T H E R M®- K for top up purpose in system filled with mineral oil based HTF.  


  • Kin. Vis. Of sigma T H E R M®- K is just 20cSt at 40 °C as compared to 32-36 cSt of mineral oil based HTF. Co Efficient of heat transfer is inversely proportionate to Kin. Vis. Of the fluid. Thus as compared to mineral based HTF sigma T H E R M®- K gives higher rate of heat transfer.  

  • Due to lower Kin. Vis. There will be lower load on circulation pump that saves  power consumption.  

  • Thermal stability of sigma T H E R M®- K is much higher than any mineral oil based HTF, using sigma T H E R M®- K will increase life of HTF.  

  • Carbon deposition problem will be reduced drastically.  Top up requirement will be reduced.