Process fluids, known as heat transfer fluids, hot oils, or thermal oils, are used to produce high operating temperatures at low pressures. They are used in many manufacturing processes that require consistent, responsive heating to maintain pump production.
The main feature of heat transfer fluid technology lies in its ability to generate high temperatures under low system pressures. Heat transfer fluid technology has many advantages over traditional technologies like steam heating or direct fire heat. This technology is highly efficient and non-corrosive and provides uniform temperature regulation throughout your Perth pump system.
Heat transfer fluid systems are vital production assets and must be properly maintained to prevent unplanned downtime. These systems are often trouble-free for long periods of time. However, it is easy to neglect them until an unexpected failure occurs. The system’s reliability and performance are dependent on the implementation of a fluid management program and protection from potential degradation pathways.
Why is it so important to choose the right fluid for smooth operations?
If you choose the wrong fluids for your Perth pumps, it is likely that your system will suffer from accelerated degradation and equipment failures. Heat transfer systems are designed to be low-maintenance and safe when they are used correctly. If these factors are assumed, the dangers of high-temperature operations will grow exponentially. Fluid selection is essential. This is where it becomes difficult to remember the importance of establishing a partnership with the supplier of the thermal fluid.
As Perth’s centrifugal pump experts, we have put together three main strategies to optimise fluid performance in thermal fluid systems:
Make sure the fluid meets the application requirements
This is a crucial consideration for your Perth centrifugal pumps to ensure the long-term performance of the thermal fluid. There are many heat transfer fluids available, but it is important to only purchase the fluid from a reliable supplier. Based on real performance data and scientific thermal stress analysis, established thermal fluid suppliers can determine the true operating limits. To match system specifications, the fluid must have the same thermal properties as the rest of its operating range.
High-temperature synthetic aromatic chemicals should be considered for operating temperatures exceeding 300 °C. These benzene derivatives take advantage of the thermal stability inherent in the aromatic structure. Although they are more specific, aromatic thermal fluids offer greater flexibility and higher extreme temperature capabilities than mineral oil fluids.
Here are some fluid selection tips for your Perth centrifugal pump system:
- Aim to achieve a 14°C cushion between the maximum process temperatures and the fluid’s maximum temperature limits. This cushion will ensure that the fluid is able to provide consistent service for a reasonable life span.
- Consider the possible start-up temperatures of the fluid given the climate. Certain fluids are more pumpable than others, which can save you money on heat tracing or freeze protection.
- Make sure the fluid is compatible with all the piping, gaskets, and seals with which it will come into direct contact.
- You should choose a fluid that is high in purity, high efficiency, and high thermal stability.
Apart from the points above, it is important to be aware of any potential handling and health hazards associated with each candidate fluid in your pump control system.
Three of the most serious threats to fluid performance are contamination, oxidative degradation, and thermal degradation.
Thermal degradation is when liquid molecules absorb more heat than they can release. Excessive thermal stress can cause “cracking,” which is the breaking of molecular bonds. This causes irreversible damage to fluids and changes in their physical properties.
In extreme cases, thermal degradation may cause heavy coking or even the failure of heater tubes. The following can help to reduce thermal degradation rates:
- You must consider the temperature requirements when choosing the appropriate fluid.
- Keep to the recommended maximum temperatures.
- At all times, ensure that the fluid flows properly through the heater.
When hot fluid reacts to atmospheric oxygen in reservoirs or vented expansion tanks, oxidative degradation takes place. Fluid oxidation can cause significant problems in fluid performance and quality. If not corrected, oxidation can lead to organic acids. The fluid’s total acid number (TAN) increases as oxidation progresses.
Fluid viscosity can be increased by oxidation, which can lead to sludge precipitation and, eventually, fouled surfaces or plugged lines. Most systems can be prevented oxidation by covering the expansion tank with an inert gas like nitrogen. Cold-seal containers or thermal buffer tanks are options if blanketing is not possible. Although it is easy to fix, oxidation is responsible for more than 90% of all cases of premature fluid degradation.
Process leaks and operational errors are the most common causes of contamination. Common errors include using the wrong fluid, sharing process equipment, and not following proper clean-up procedures. The contaminant is what determines the effects of contamination. Water can quickly manifest itself, leading to pump cavitation and unexpected venting. Other cases may see rapid degradation of the contaminant, which can lead to higher acidity, low or high boilers and carbon generation, as well as fouling of surfaces. Many side effects of contamination can occur, including reduced heat transfer, equipment failure, and lower operational safety.
Routine system reviews can be invaluable in managing fluid degradation risks. Every week, they walk the system and note any leaks or unusual sounds. You should address small issues quickly to avoid bigger problems.
Proper start-up, shutdown, and maintenance of the system are essential for its long-term success. The heater should be set to low until the turbulent flow is established. This will prevent the heater from overheating. When the heater is turned off, the main circulation pumps in Perth, if any, should continue to run until the outlet temperature of the heater reaches 82°C.
Put in place a maintenance program
To ensure that the thermal fluid performs well, it is important to monitor its condition. Unexpected fluctuations in the fluid’s quality can cause unplanned downtime and affect the system’s ability to meet production demand. Routine analysis can alert the user about fluid conditions and help detect equipment malfunctions before they become a major problem.
Sound management principles are key to maintaining the performance of your thermal oil. You must select the appropriate fluid for your operation, reduce or eliminate fluid degradation risks, monitor the fluid conditions, and perform preventive maintenance. If you need help with your pump control system, contact us at APT Water today.