The ins and outs of thermal fluid analysis
EDITOR ’ S CHOICE PROACTIVE FLUID MONITORING
GLOBAL HEAT TRANSFER
The ins and outs of thermal fluid analysis
How do you know when a kitchen sink is about to clog and overflow ? Most residential pipes are hidden , so food waste and product build-up can go unnoticed until it leads to damage . In manufacturing , leaving pipework unmonitored can lead to unexpected downtime and safety issues , particularly when working with thermal fluids , so proactive monitoring is the best way to prevent these problems . Here Clive Jones , managing director of thermal fluid supplier and condition management expert , Global Heat Transfer , outlines the steps of thermal fluid analysis for proactive fluid monitoring and how businesses can use the results to increase fluid lifespan .
Thermal fluids are designed to operate effectively for many years , but over time , operating at and maintaining high temperatures means that the oil will naturally degrade . Thermal fluid analysis provides a deep dive into the condition of the oil and allows businesses to gain expert advice about how to effectively maintain the fluid and the system . Analysis also ensures health and safety compliance with The Dangerous Substances and Explosive Atmospheres Regulations ( DSEAR ) of 2002 and UKEX ( formally the Explosive Atmosphere Directive ATEX 137 in the UK ).
To comply with relevant safety regulations , such as DSEAR in the UK , manufacturers must take proactive steps to reduce the risk of fire or explosion caused by working with dangerous substances . If this fluid is left unattended , for example , fluid degradation — where thermal oils can be broken down into carbon molecules that stick to the pipes — can occur , reducing heat transfer efficiency . If not monitored effectively , degradation may go unnoticed until it causes significant production issues and system failure , leading to costly downtime and risk to health and safety .
Instead of reacting to issues , regular thermal fluid sampling and analysis enables businesses to proactively monitor fluid condition and intervene before issues impact production , extending thermal oil lifespan and reducing maintenance costs .
ANALYSING A SAMPLE
Effectively monitoring heat transfer oil condition requires engineers to regularly
To comply with relevant safety regulations , such as DSEAR in the UK , manufacturers must take proactive steps to reduce the risk of fire or explosion caused by working with dangerous substances .
take samples of the oil and send it to a specialist for analysis . Historically , thermal fluid experts conducted seven tests , however , in our experience conducting eleven tests provides results that best reflect the reality of what ’ s happening inside the system .
Once the sample arrives to an impartial lab for testing , an analytical chemist will look at its appearance , looking at the colour and for any particulates in the fluid . Fluid colour can range from clear and bright , which is common to newer fluids , to hazy , which can be a sign of high-water levels , to dark , which shows there is a high level of carbon build up in the system . These initial observations are confirmed in later steps to ensure the thermal fluid specialist provides the best recommendations .
Testing the water content of the oil is vital to regulatory compliance . Any water in the system and oil will convert to steam and expand , increasing the pressure in the system . By analysing water content , analysts and heat transfer fluid specialists can advise on how best to reduce the risks associated with high pressure .
The next step is to test viscosity and assess the impact the fluid has on the system pumps . If a fluid is too thick , flow rate will reduce , increasing the pressure on the pumps . This reduced flow rate can create hot spots in the system , leading to inconsistent heating or cooling of products that results in waste products , increased damage to the system and rising maintenance costs .
Measuring the level of carbon in the system is key to understanding the degree of system fouling . If the thermal fluid expert detects high levels of carbon deposits , it suggests that there is more carbon in the system , which can harden in the pipes , acting as an insulator . As a result , the entire system heat transfer efficiency will reduce and more energy is required to heat up the system . Manufacturers should consider how they can prevent carbon build-up as it can create hot spots that accelerate wear on the pipes and increase the risk of leaks .
Analytical chemists will then test the total acid number ( TAN ). If there is a high level of acid in the fluid , it can lead to increased corrosion of the system and accelerated carbon creation . By measuring this parameter , manufacturers can understand how the fluid impacts the pipes of the system , ensuring that they can slow down degradation and reduce the frequency of scheduled maintenance needed to replace corroded parts .
Particulate quantity and iron tests highlight the degradation of components of the heat transfer system . Both tests can show signs that there is wear in the system that needs addressing so that manufacturers can intervene before the wear turns into a dangerous leak .
Manufacturers should also look at the results of the Pensky-Martens Closed Cup flash point , Cleveland Open Cup flash point and fire point tests to reduce health and safety risks . The industry standard suggests that closed flash point of the fluid cannot be below 100 degrees Celsius , because it means the fluid could ignite at lower temperatures , so these tests are vital to understanding if the fluid is safe for use .
REPORTING
Once analysis is complete , the thermal fluid expert delivers a report to the plant manager , organising points into cautions , actions , or serious findings . At this point engineers
22 PECM Issue 64