Heat transfer oils from ADDINOL
Heat transfer oils are extremely temperature-resistant mineral or synthetic oils which ensure that heat is transferred to a process in industrial plants by dissipating heat elsewhere. The heat transfer oils are usually transported in pipelines within a closed circuit.
Many industrially manufactured products and their production processes require heat. A direct heat supply is often not possible or brings disadvantages. A heat transfer system provides a remedy. It works indirectly with heat transfer oils based on special mineral oils or synthetic liquids. Heat transfer oils are generally in continuous use and must function trouble-free for many years. They have a particularly high temperature resistance. At the same time, heat transfer oils can also have a cooling effect by removing heat.
ADDINOL Heat Transfer Oil XW 15 and XW 15 HT are based on synthetic base oils. The oils have often proven their high performance in practice. The products achieve significantly extended oil service lives compared to mineral thermal oils.
Information about heat transfer oils
Fields of application of heat transfer oils
Heat transfer oils are preferably used as heat transfer medium in heating systems or in combined heating/cooling systems. The oils remain stable at temperatures above 300 °C and ensure optimum heat transfer. It is mainly used in systems where direct heating is not possible. This allows both hazardous and sensitive substances to be heated gently. Classic examples for the use of heat transfer oils are:
- Distillation columns
- Synthetic resin production
- Heat exchangers in process plants
- Polymerization boiler
- Waste heat recovery systems
- Heating and drying plants in the cement industry
- Calenders for paper and plastics
Properties of heat transfer oils
Heat transfer oils must also be able to cope with different requirements due to the wide range of possible applications. Each system is different and therefore it should be checked exactly which heat transfer oil can be used for the process. Water and steam are used in many plants only at temperatures below 200 °C. In high-temperature processes, the operators have to use mineral or synthetic oil as a heat transfer medium. In contrast to water, heat transfer oil does not have to be operated at overpressure, which results in increased plant safety. The oil also protects the pipes from corrosion.
The following properties are required in order for heat transfer oils to be used effectively in systems:
- Low viscosity
- High thermal stability
- High thermal conductivity
- High flash point
- Compatibility with common plant materials
- Ecologically as harmless as possible
- Good oxidation resistance
- Low vapour pressure
The individual properties depend on the specific application. ADDINOL will be pleased to help you and advise you on the selection of the optimum heat transfer oil.
If, for example, you operate a plant in a temperature range of 200-300 °C, the cheaper mineral oils are usually sufficient to transfer the heat. If the temperature rises above 300 °C, it is advisable to choose synthetic oil (e.g. ADDINOL XW 15 HT) as this has a higher temperature resistance and can be used the plant longer.
Thermal stability of heat transfer oil
The thermal stability of a heat transfer oil is one of the most important properties of the fluid. It is defined as the resistance of a heat transfer medium to thermal stress and a specific temperature. Poor thermal stability leads to increased thermal decomposition (cracking), which greatly shortens the service life of a heat transfer medium. Thermal decomposition can never be stopped completely, but can be delayed for many years if the oil is suitable for the application.
During the decomposition of the oil, the molecular structure is broken down, which produces gaseous, liquid and solid decomposition products that can change the properties of the heat transfer medium such as viscosity or flash point unfavourably. If the load of the heat transfer oil with degradation products is too high, an oil change is recommended before damage to the system occurs.
Monitoring heat transfer oil
Use our analysis service to have the condition of your heat transfer oil checked in the laboratory. Only in this way can you be sure that your system will function as desired. The
heat transfer media should be checked after major changes in the operating temperatures at least after three month, if necessary after commissioning and in the event of irregularities in system operation. In addition, according to DIN 4754-1 in Germany, the heat transfer medium must be tested for its suitability for further use at least once a year. Other regulations apply to other countries. Parameters such as viscosity, flash point, water content and the concentration of foreign substances provide information about the oil condition (test according to DIN 51529). This allows you to quickly detect major deviations in oil properties and progressive decomposition before problems with your system occur.
To prevent thermal decomposition of the heat transfer oil, you can also take the following steps:
- Controlling the heat flow of the plant
- Maintenance of pumps and filters
- Carry out analyses
- Filter out impurities larger than 10 μm
- Professional start-up and shut-down of the system to protect the oil (no too fast heating/cooling of the system)