Why Thermal Heating Fluid Burns Up In Your Thermal Fluid Heater?

Thermal fluid degradation or “burn-up” in a thermal fluid heater can be a significant issue that leads to the loss of fluid properties, system inefficiency, and potential equipment damage. Here are the common reasons why thermal heating fluid may degrade or burn up in your thermal fluid heater:

1. Overheating:

Exceeding the thermal fluid’s maximum recommended operating temperature can lead to ‘cracking’ or breaking down of the fluid. This may produce low molecular weight fragments and solid carbon (coke) which can foul the system.

2. Oxidation:

Prolonged exposure to air, especially at high temperatures, can lead to oxidation of the fluid. Oxidation produces acidic compounds and can lead to sludge formation which reduces system efficiency.

3. Contamination:

Introduction of foreign materials, such as water or process chemicals, into the thermal fluid can initiate degradation. Water, for example, can cause localized overheating (steam blanketing) and may also contribute to fluid oxidation.

4. Poor System Design:

System designs that do not allow for the complete and efficient circulation of the thermal fluid can lead to localized overheating and fluid degradation. For example, dead legs where fluid becomes stagnant can be problematic.

5. Extended Operation without Maintenance:

Running a thermal fluid system without regular fluid analysis and maintenance increases the chances of fluid degradation. Regular monitoring can identify issues like acidity, contamination, and reduced flash point before significant damage occurs.

6. Thermal Cracking:

When thermal fluid is exposed to significantly high temperatures, the fluid molecules can crack, creating lighter volatile components and heavier coke particles. The lighter components can be problematic from a safety perspective (lower flash point), while the heavier particles can foul the system.

7. Pumping Issues:

Inadequate pumping can result in poor circulation, leading to localized overheating and fluid degradation. Ensuring the pump is correctly sized and functioning is crucial.

8. Inadequate Expansion Volume:

Not having enough expansion tank volume for the thermal fluid to expand when heated can lead to fluid degradation. It can result in the system operating under pressure conditions that exceed design limits, causing the fluid to degrade rapidly.

9. Lack of Nitrogen Blanketing:

For systems operating close to or above the fluid’s flash point, nitrogen blanketing (inerting the expansion tank with nitrogen gas) can prevent fluid oxidation and degradation by keeping oxygen away from the hot fluid.

10. Improper Startup and Shutdown Procedures:

Rapid heating during startup or improper shutdown procedures can induce thermal stress in the fluid, leading to degradation.

To avoid such problems, it’s important to:

Regularly monitor the fluid condition through analysis.
Follow the fluid manufacturer’s recommended operating conditions closely.
Maintain the heater, pumps, and other components per manufacturers’ recommendations.
Design the system to avoid stagnant zones and ensure complete and efficient circulation of the fluid.
Regular maintenance, along with adherence to operating specifications and guidelines, can significantly prolong the life of thermal heating fluids and maintain system efficiency and safety.