Waste oil recycling contributes very much to climate protection through (CO2) energy saving. Compared to the production of base oil the re-refining of waste oil uses 34 % less resources. In the sixties the German government was subsidising the re-refining of waste oil. Because of that the use of waste oil as a fuel was neglected.
The used oil re-refining is the process of restoring used oil to new oil by removing chemical impurities, heavy metals and dirt . Used industrial and automotive oil is recycled at re-refineries. The used oil is first tested to determine suitability for re-refining, after which it is dehydrated and the water distillate is treated before being released into the environment. Dehydrating also removes the residual light fuel that can be used to power the refinery, and additionally captures ethylene glycol for re-use in recycled antifreeze.
Next, industrial fuel is separated out of the used oil. Then vacuum distillation removes the lube cut (that is, the fraction suitable for reuse as lubricating oil) leaving a heavy oil that contains the used oil's additives and other by-products such as asphalt extender. The lube cut next undergoes hydro treating, or catalytic hydrogenation to remove residual polymers and other chemical compounds, and to saturate carbon chains with hydrogen for greater stability.
Final oil separation, or fractionating, separates the oil into three different oil grades: Light viscosity lubricants suitable for general lubricant applications, low viscosity lubricants for automotive and industrial applications, and high viscosity lubricants for heavy-duty applications. The oil that is produced in this step is referred to as re-refined base oil (RRBL).
The final step is blending additives into these three grades of oil products to produce final products with the right detergent and anti-friction qualities. Then each product is tested again for quality and purity before being released for sale to the public.
In 1968 DIRK Spezial Schmierstoffe merged with one of the leading coal mining companies in the Ruhr District - Harpener Bergbau AG - whose owner was Derner Ölwerke GmbH, Dortmund. The aim was to produce automotive and industrial lubricants by re-refining of waste oil. Georg Dirk was installed as MD of the company which would trade as DIRK-DERNER ÖLWERKE. Mr. Dirk suggested to revive the closed benzol plant owned by Harpen and use this asset consisting among others of an intact infra structure of distillation facilities and large oil storage tanks as well as oil blending plants to produce re-refined lubricants for automotive and industrial applications. The existing plant owned a pipeline from its location at Bochum to the canal port of Dortmund and was able to load large canal ships for transport of the oil to German and international customers.
Mr. Dirk supervised the conversion of the benzol plant which was completed within 12 months. It immediately became the largest re-refinery in Europe.
To obtain sufficient waste oil Dirk operated a fleet of small road tankers which collected the waste oil and delivered it to rail tankers provided at all main rail heads. The tankers transported the waste oil. On reception the waste oil was tested to establish if it was suitable for re-refining.
The marketing of the DIRK oil brand was successful. Dirk started – ahead of his competitors - to produce also synthetic engine oil and introduced oil bottles for car engine refill. These products were sold through supermarkets and automotive spare part traders.
Harpener Bergbau AG experienced economic troubles in the 1980ies and sold the plant - renamed to HARPEN ÖL - to a re-refinery in Dollbergen which is no more in existence. The Bochum plant was scrapped.