Posted on Leave a comment

Eight ways to extend the life of heat transfer fluid

SC image

While the deterioration of heat transfer fluid (HTF) is always inevitable, operators can impact how long it takes to degrade. Extending the active service life of HTF can have multiple benefits for enterprises, from reducing maintenance and service costs to decreasing annual spending on fluids.

The key threats to useful HTF service life are thermal and oxidative degradation, and external or process contamination. As a result, to prolong fluid lifespan, these issues must be answered effectively. Here, we look at some of the most often used methods for extending the service life of HTFs.

Monitor heat flux

Operators should always select a suitable heat transfer fluid for their application that can remain thermally stable at the required operating temperatures. However, system temperatures must be monitored as spikes in temperature can result in thermal degradation.

Operators must monitor the main heater for alarms and respond to notifications and blinking red lights swiftly. Where data isn’t electronically collected, they should measure key parameters like pressures, temperatures and flow rates on gauges at different system locations to ensure results remain consistent with specifications.

Ensuring that the HTF in use and operating temperatures are compatible will ensure fluids remain useful for longer.

Perform fluid analysis

Analysing the heat transfer fluid in the system is critical to prolonging its service life. Too often, fluids are discarded before their usefulness is spent, or left in systems long past their ability to be effective.

Regular fluid analysis will give detailed information on the HTF in service, showing signs of thermal deterioration, levels of oxygen present and contaminants that have accumulated, which could be impacting performance.

Proactive analysis can identify issues with key parameters like fluid viscosity, flashpoint, acidity, insoluble solids and moisture contamination early, so that corrective actions can be taken that enhance fluid performance and lifespan.

Follow best practices for heat transfer fluid testing

Fluids should be tested when brand-new systems are in the first year of operation, as major issues that can impact the HTF will show up in results. HTFs should also be tested a week or two after a fluid change, and larger systems should always have an annual test.

Dilute the heat transfer fluid

It is possible to extend the useful service life of a heat transfer fluid through dilution. Operators can top up the existing HTF in their system with a supply of brand-new thermal fluid, providing that the product introduced is miscible with the solution already in use. Once combined in the system, the resulting fluid will have increased heat transfer efficiency.

Filter the oil

Insoluble solid contaminants from processes like varnish, metal shavings and other debris can affect how well heat transfer fluids perform their role. Effective filtering allows operators to improve the purity of fluids, enabling them to function more effectively.

Blanket the expansion tank

An effective way of minimising fluid oxidation is blanketing the expansion tank using an inert gas like nitrogen, natural gas or carbon dioxide. The purpose of blanketing is to create and keep a nonreactive atmosphere within the vapour space in the expansion tank. This effectively prevents air and moisture entering, which adversely impact fluid lifespan.

A supply of inert gas, controlled by pressure regulators for both outlet and inlet flow, is needed to achieve this level of protection.

Remove used heat transfer fluid

When heat transfer fluid that no longer has any useful properties left is allowed to remain in the system, it can impact fresh HTF entering. The sought-after attributes of a heat transfer fluid will be immediately lessened when they are contaminated, with spent fluid automatically ageing its active service life span from day one.

Use a flushing agent

Before replenishing heat transfer systems with a virgin supply of fluid, operators should use a flushing agent to remove spent fluid or contaminants present. Flushing agents will also rid the system of any excess moisture left over from cleaning processes.

To sum up, there are multiple ways that system operators can proactively ensure that the heat transfer fluids in use remain fresh and effective for as long as circumstances allow. A considered and preventative approach can keep the heat transfer system safe and productive before the inevitable fluid change over and comprehensive system cleaning occurs.

Operators are always encouraged to make regular inspections of not just the systems they look after, but also their components and the heat transfer fluid that serves them – including correct laboratory testing of HTFs in use.

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.