Plant & Works Engineering
Top tips for thermal fluid systems
Published:  08 June, 2017

Dave Dyer, technical sales engineer at thermal fluid specialist Global Heat Transfer offers his advice for facilities managers who want to better understand their thermal fluid.

According to the Consumer Electronics Association, users expect their smartphones to have a lifespan of five years. However, Recon Analytics reported that the average handset replacement time is actually around two and a half years. Understanding and mitigating the factors that reduce technology lifespan can elongate device life, leading to better return on investment. The same simple rule applies to operating and maintaining a heat transfer fluid system.

In the process and chemical industries, heat transfer systems using thermal fluid often operate behind the scenes. This means that the plant or facilities manager may be unaware of how important proactive maintenance is to system efficiency and safety. There is a common misconception that thermal fluid systems that have been operating for a long time without a major incident are unlikely to break down. The reality is that all heat transfer systems require regular maintenance and thermal fluid tests to ensure they are in good health.

Cause for concern

Thermal fluid can lead to costly downtime if left unmanaged. If a facilities manager doesn’t ensure regular representative sampling and respond with appropriate corrective maintenance, a range of problems may occur. A lack of regular sampling and maintenance can lead to a carbon or acid build up, lack of flow and overall, a less efficient system, which often impacts quality of product and overall yield.

A common problem is that thermal fluid degradation leads to carbon build up in the pipes. Because carbon is a natural insulator, the system transfers less heat and requires more energy to achieve the desired temperature, making it less efficient and more costly to run.

Regular sampling, expert analysis and interpretation of data and proactive maintenance means a facilities manager can act on an early warning sign in a thermal fluid system, fixing the problem quickly, improving system performance and minimising downtime. In order for this to be done effectively, on site staff should have a basic understanding of the heat transfer system and when sampling or maintenance should be done.

Train staff

Facilities managers should ensure a comprehensive understanding of the legislation surrounding thermal fluid – the Dangerous Substances and Explosive Atmospheres (DSEAR) regulations and the Explosive Atmosphere Directive (ATEX 137).

As well as the facilities manager, additional staff will be operating the system. This means that a trained member of staff will always be on site or at hand. The importance of thermal fluid maintenance to operations should also be relayed to company directors, including the risks and costs of downtime.

Training should cover the basic system operations, such as the start up and shut down procedures. Training should also include a comprehensive list of what maintenance staff should check on a regular basis, including potential leaks, wear and tear, faulty gauges, heat and flow.

The facilities manager must also ensure a regular survey to check for mechanical wear and tear in the thermal fluid system. Common examples of system components that may need maintenance are gauges, pipe insulation, gaskets, which may be leaking or worn-out.

Increasing staff knowledge base improves the safety of the system, as well as productivity. For example, in cold winter months the thermal fluid in the header tank can wax up and freeze. This puts a strain on the pump when starting the system and means valuable production time can be lost because of a delay in system set up.

An experienced team member would be able to prevent this delay by leaving the main circulation pump running 24/7 with no heat from the heater. This will produce around 60 degrees of heat, keeping the thermal oil at a viscosity where it can flow through the system. In turn, this ensures production can restart straight away.

Thermal fluid condition

The only way a facilities manager can have an accurate, up to date record of the thermal fluid condition is by ensuring correct sampling. Sampling checks for degradation in the fluid, low flash points or water in the system, which affects safety and regulatory compliance. If a sample is taken incorrectly and is not from a hot closed and live system, this can misrepresent the condition of the fluid, so it is important that this is done correctly, usually by an in-house or external thermal fluid expert.

Regular sampling can identify problems early on, which gives the facility manager more time to rectify them. For example, one common problem for heat transfer systems is the production of light ends as a result of hydrocarbon chain breakdown. To address the issue, the client can use a light ends kit to bring up the flashpoint of the oil. Because light ends boil and ignite at lower temperatures, using a light ends kit to remove them improves system safety to meet regulatory requirements.

Thermal fluid top ups

The facilities manager should ideally have access to spare thermal fluid. This is because a thermal fluid system uses about 5% of its volume each year. This fluid may also be urgently needed if there is a leak in the system.

If the company has a knowledgeable team of engineering maintenance staff, they can top the system up themselves. Failing that, the facilities manager should have an emergency contact that can assist them in tackling the issue.

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