Electrical Oil Services collects and recycles used mineral insulating oils. Depending on their quality and composition, the company either regenerates the oil for return to service as a transformer oil or processes them into a base oil. Most of the oils collected can be reused as insulating oil following appropriate treatment. However, a smaller proportion is no longer suitable for this purpose. For these oils, further processing into base oil is a sensible alternative. This ensures that the raw material remains within the industrial cycle, rather than being incinerated, and can be reused as a starting material for various applications. Find out more here.
“We collect and recycle transformer oil. Around 60 per cent of the oil we collect can currently be reused as insulating oil of the same quality as new oil after appropriate treatment. With our new centrifuge technology, this figure will increase to around 80 per cent in the future. However, a smaller portion is no longer suitable for this purpose. Instead of burning it, we produce base oil from this. Base oil is a versatile raw material used in a wide range of industries, such as metalworking, road construction, and rubber products. We find our work particularly rewarding because we can turn used insulating oil into a useful product almost every time, thereby keeping the material within the circular economy.”
— Tom Lowcock, Key Account Manager, Electrical Oil Services
In the field of transformer oil management, similar questions crop up time and again: What actually happens to used transformer oil once it has been collected? Why can’t all waste oil be reprocessed into insulating oil? What technologies are used to extract base oil from it? And what is this base oil subsequently used for? Read the answers here.
The first step in the recycling process begins with the systematic collection of used mineral insulating oils.
After collection, the insulating oil is analysed and assessed. The aim is to determine whether the oil is suitable for processing into regenerated insulating oil or whether it would be better used for processing into base oil. Various factors are taken into account, including:
Degree of ageing of the transformer oil
Possible contaminants
Chemical composition
Technical reusability as insulating oil
The vast majority of the collected transformer oils can be regenerated into high-quality insulating oil following appropriate treatment. These transformer oils can be returned to their original technical scope of application and can be reused in transformers. However, a smaller proportion of these insulating oils no longer meets these requirements. For this fraction, processing into base oil offers a sensible alternative within the circular economy.
Not all used transformer oil can be economically or technically viable to reprocess into insulating oil. In some cases, ageing processes or certain contaminants have altered the oil’s properties to such an extent that returning it to service as transformer oil is no longer possible or advisable.
Instead of recovering energy from these insulating oils or incinerating them, Electrical Oil Services takes a different approach: the raw material should remain within the industrial cycle as far as possible. Conversion into base oil therefore represents a sustainable and technically sound use.
What exactly is base oil?Base oils make up the majority of lubricants and determine their fundamental properties such as viscosity, ageing resistance and thermal behaviour.
In the context of the circular economy, base oils can also be obtained from reprocessed mineral insulating oils and thus serve as a raw material in new industrial applications. |
The technologies used to produce base oil from used transformer oils are based on similar principles to those used in the regeneration of insulating oil. The aim is to remove undesirable components from the oil and stabilise the properties of the base oil.
An important part of this process is the mechanical separation of impurities and ageing products. Modern centrifuges play a central role in this. Thanks to high centrifugal forces, they enable solids, water and other undesirable components to be efficiently removed from the oil.
Electrical Oil Services produces base oil at its sites in Stanlow, UK, and Duisburg, Germany. There are four steps:
Step 1: Initial treatment of the old transformer oil
Removal of gases, water and solid contaminants to prepare the transformer oil for the regeneration process
Step 2: Introduction into the process columns
Passage through adsorption columns to remove acids, polar ageing products and other undesirable components
Step 3: Repetition of the regeneration process
Multiple treatments to further reduce ageing products and stabilise oil quality
Step 4: Reactivation of the process columns
Regeneration of the adsorption materials used to ensure consistently high purification performance
For a more in-depth look at the technologies used, this interview provides further details:
Base oil is a versatile industrial feedstock. Unlike transformer oil, it is not limited to a specific application within the energy infrastructure. Rather, it forms the basis for numerous products across various industrial sectors.
Typical applications of base oil include, for example:
Metalworking fluids
Road construction products
Rubber and polymer products
Various industrial formulations
Do you have any questions? We’d be happy to advise you.
With base oil forming part of the circular economy, it becomes clear that even that portion of collected transformer oil which cannot be reused as insulating oil retains significant value. By processing it into base oil, the raw material remains within the industrial cycle and finds new applications and the end user avoids the need to pay more for a virgin material.
At the same time, it is evident that modern processing and regeneration technologies make it possible to continuously increase the proportion of reusable oils and utilise resources more efficiently.
The recycling of transformer oil thus not only contributes to security of supply, but also to a more sustainable use of existing raw materials in the energy and industrial infrastructure.
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