Plants 

Dehydration – Basic distillation I and II

All oils at the Mineralöl-Raffinerie Dollbergen are heat-treated under partial vacuum in these distillation units. The dehydration plants are used for distilling out water and low-volatile components (e.g. petrol).

The remaining sump product is known as dehydrated, or dried, oil. It has a flashpoint of over 61°C  and a water constituent of approximately 0.1 – 0.2 wt./%.

These dehydrated oils are fed into the following reprocessing stages, according to their quality classification.

Flash distillation

Used oil dehydrated in the atmospheric distillation unit is fed from 100m³ storage tanks into the flash distillation unit. In this unit, there are several distillation stages. First the fractions akin to light heating oil are distilled out in a process similar to the flux oil distillation.

The sump product now found on the floor of the column is now separated in our so-called flash distillation (composed of a flash-drum and two thin-layer evaporators) into a base oil raw distillate("flash distillate) and a distillation residue ("bottom product").

All the additives in the dehydrated oil, sooty particles and metal filings etc. which were previously taken up by the used oil make up this distillate residue. The flash distillate already displays characteristics of the base oil, and is a semi-transparent darkish brown. Heavy metals for instance are no longer present in this raw product.

The thermal oil furnace of this flash distillation unit is mainly fired with our own fuel. The waste gases are treated by a wet scrubber so that the clean gases comply with the terms of operating approval.  The waste water from the washer goes into the factory's own water treatment plant.

By the insertion of a high-temperature combustion chamber, it is also possible to burn the exhaust of the refinery in this furnace. This has contributed to a substantial improvement regarding exhaust emissions.

Enhanced Selective Refining 

The patented process for "Enhanced Selective Refining" is based on the process of liquid-liquid extraction process. The vacuum distillates recovered from used oil are intensively mixed with a solvent to remove undesired components and impurities. As a result we offer a unique high quality base oil named Kernsolvat^®. The extract from the process is then used as heavy fuel oil and the solvent, in turn, is recovered and re-used in the process. Hence, no waste is generated.

The superior Kernsolvat^® forms the basis of our range of high-quality lubricants:

• industrial lubricants 
• metalworking oils 
• motor oils 
• gearbox oils 
• hydraulic oils

For this unique innovation the construction of the "Enhanced Selective Refining" was supported by the European Union within the context of the LIFE-environmental programme and by the State of Lower Saxony within the context of a research and development programme.