Heat transfer fluids are exposed to varying process conditions that may result in degradation. In the table below, we present three common problems experienced with heat transfer fluids alongside their associated causes and consequences.
- Exposure of Heat Transfer Fluid to air leads to an oxidation reaction that degrades the fluid over time.
- Absence of blanketing with an inert gas (e.g N2,Ar)
- Increase in viscosity (decrease in heat transfer efficiency)
- Increase in Total Acid Number (TAN). Leads to corrosion problems if moisture is present
- Fouling/Formation of sludge (fouling decreases heat transfer efficiency and increases maintenance costs)
- Fluid discoloration
See our recommendation on Oxidative degradation in the article, ‘Solutions to Heat Transfer Fluid Problems’
- Heating a Heat Transfer Fluid above its bulk temperature results in a cracking of the fluid. A rapid rise in burner/boiler temperature can also crack the fluid.
- Low flow
- Improper burner flame impingement
- Decrease in viscosity, flash point, fire point and autoignition temperature (safety concern)
- Carbon varnishes foul heat transfer surface
- Fluid has pungent/sharp smell
See solution in the article, ‘Solutions to Heat Transfer Fluid Problems’
See our recommendation on thermal cracking in the article, ‘Solutions to Heat Transfer Fluid Problems’
- Pipe/vessel leaks may cause process to enter into the Heat Transfer Fluid causing/accelerating fluid degradation
- Water may get into the expansion tank
- Poor drainage and flushing of degraded Heat Transfer Fluid before replacement with new fluid.
- Rapid fluid degradation
- Pump cavitation (in a case where water vapor is converted to steam as temperature is increased)
- There could also be adverse effects on fluid viscosity, volatility and heat transfer efficiency
See our recommendations on fluid contamination in the article, ‘Solutions to Heat Transfer Fluid Problems’