The NESS Light-ends removal system is a product in the NESSessities concept which constantly increases safety, availability, durability and efficiency in thermal oil systems. One of the 3 most important factors for a good quality is a stable flashpoint. The NESS Light-ends removal system helps you ensuring this permanently.
No problem at all! Like all NESSessities, also the NESS Light-ends removal system is designed as an individual module. Existing processes are not influenced. because the light-ends removal takes place in the bypass flow. This concept allows the relatively easy retrofitting also for already existing systems.
Basically, there are two types of systems for light ends removal at NESS: a passive system and an active system.
The passive light ends removal system works with gravity. That means that it must be installed at least 2m above the highest point of the system (mostly the expansion tank). This often requires an additional steel structure which would preferably seem the thing to do when a new plant is planned and not for retrofitting. The solution is feasible for systems with up to 110,000 litres of thermal oil.
The active light ends removal system is very flexible because it is equipped with its own pump pump and a frequency converter. Therefore, among others, its implementation in existing systems can be planned better and it can also be used optimally for systems with more than 110,000 litres of thermal oil.
What product solutions are available for your system you will read here
Besides a certain inlet pressure of the thermal oil, nitrogen, cooling water and control air will be required in addition. Due to its own pump and control unit, the active light ends removal system certainly needs the respective power supply.
Please find more details here.
Nitrogen is always required for the operation of the light-ends removal system. This is required for the intertisation and the generation of overpressure within the system. Consumption depends on the quantity of light-ends in the oil.
| Nitrogen cylinder (50 litres / 200 bar) | |
| With fresh oil | approx. 6 days |
| With used oil | approx. 2 days |
To ensure the continuous provision of nitrogen and simultaneously to reduce the running costs, we recommend using a nitrogen generator with a 750-l nitrogen tank.
Cooling water is always required for the operation of the light ends removal systems. While the passive light ends removal systems mostly work without cooling water (due to air cooling), it is highly recommended for active light ends removal systems. In warmer regions with ambient temperatures of more than 25ºC it is even always required. Water cools the condenser in which the hot, gaseous light ends are cooled down and condensed.
| Volume flow of cooling water | 200 litres / hour |
If the recommended inlet temperature is below 250 °C, removal of the light ends is still possible, but it will be clearly worse than at the recommended temperature.
Indeed, also water is removed from the thermal oil additionally to the light-ends. The evaporation temperature of water is approx. 100 °C and therefore, it is separated like the light-ends.
The separated light ends are collected in the light-ends collecting tank. This contains a volume of 70 litres.
It must be disposed of in accordance with the local regulations. We recommend storing in a metal tank outside the building in an explosion-proof room. The metal tank must always be kept closed and emptied by a company specialised in disposal.
Heat transfer oil is a mixture consisting of multiple components. These components distinguish by their characteristics. All components with a low boiling temperature are called light ends. The low boiling temperature also comes with a low flashpoint. In combination with oxygen, these components can most likely form an ignitable mixture and therefore, they pose the highest risk for explosion and fire.
The behaviour of light ends is like benzine and poses a safety risk in thermal oil systems.
Due to the high temperatures, hydrocarbons in thermal oil decompose to form hydrocarbon with shorter chains – the light-ends. This process continuously takes place in each system during operation; the quantity of the decomposition product however depends on temperature and the type of oil used.
Generally, the following items apply: The higher the operating temperature is, the higher is the generated quantity of light-ends. If the fraction of light-ends increases, the flashpoint of the heat transfer oil will be lower.
This process is completely normal. If, however, no flashpoint management has been implemented, problems will begin. Over time, the decreasing temperature of the flashpoint possibly endangers the operating safety. That means, light ends evaporate already at low temperatures and can become slightly flammable.
Furthermore, the increase of light ends supports cavitation on mechanical components of the systems, e.g. in pumps. Therefore, it is recommended to operate an active flashpoint management to keep the flashpoint on a continuously high and safe level.
