Thermic Fluid is the heating media which transfer the heat in close loop cycle.
It is available in two forms...
Mineral heat transfer oil.
Synthetic heat transfer oil.
Mineral oil can withstand maximum temperature up to 280° C. Synthetic oil can withstand maximum temperature up to 310°C.
Continuous use of thermic fluid systems results in to deteriorating of Thermic fluid.
The main causes for deterioration are oxidation & cracking.
Oxidation: Oxidation at higher temperatures causes formation of sticky carbon. This causes choking of the system & reduced heat transfer efficiency & also produces acidic products. These add to viscosity of the oil along with increase in corrosion rate at internal parts of thermic fluid heating system.
Cracking: Overheating of the thermic fluid caused by insufficient circulation. This results in to de-polymerization of long chain compound. This localized heating above cracking temperature of oil. Cracking results in to release higher hydrocarbons which increases viscosity & reduces flash point of thermic fluid. Polymerization cause by these hydrocarbons form deposits reducing flow rate & heat transfer efficiency.