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Low Energy Polymer Dissolving

The increasing demand for high-quality lubricants, scarcity of energy resources and changing market conditions are forcing lubricants manufacturers to look for new opportunities and processes to remain competitive with their products or to produce new high-quality products.

EDL has been offering customers active in the lubricants production a novel process for several years: the LEPD technology (LEPD = Low Energy Polymer Dissolving). This is used for low energy melting of viscosity improvers (VI improvers) directly in the base oil. The advantages compared to the state of the art are impressive in terms of both plant operation and resulting product properties.


Light and heavy lube oils have different viscosities depending on the temperature. To ensure optimum viscosity across a wide range of operating temperatures, so-called multigrade oils were developed. These multigrade oils combine good cold start properties with a good viscosity at high temperatures. This is achieved by adding viscosity index improvers. VI improvers are additives that improve the viscosity/temperature behavior of oils.

Polymers  such as polymethacrylates, styrene-butadiene copolymers and others, which are usually provided as solid polymer bales, are used as VI improvers. Based on the state of the art, these solid polymers are mechanically shredded in mixers and then dissolved in the lube oil. In this process, polymers are exposed to very high shearing forces and temperatures of 120 °C. In addition,  the required residence time is up to seven hours, which may lead to aging and turbidity of the lube oil and requires additional use of antioxidants.

Patented LEPD process

In the patented process, the polymer is gently dissolved in the base oil at a pressure of up to 10 bar and at temperatures below 100 °C in a liquefaction chamber under inert gas. Lube oil flows through the liquefaction chamber, thus getting enriched with polymer up to more than 50 %. The enriched lube oil is mixed with other lube oil to achieve a polymer content of approx. 10 %.


Advantages and energy savings

The process saves approx. 30 % of time compared to the conventional process. Due to the lower process temperature, the heat input is lower. Compared to conventional plants, it saves approx. 50 % of the required energy. In addition, there is no risk of turbidity or coking in the dissolving process, so that the final qualities of the finished oils are higher and there is no need to use additional additives such as antioxidants. Since the polymer chain structure is not modified in the gentle dissolving process, better lubricating properties of the product can be achieved.


Pilot plant for on-site tests

EDL has expanded its range of services for its LEPD technology last year by implementing a pilot plant.  Based on the test results, customers get a guarantee for the design and planning of blending plants as well as for the requested product quality. Thermische Apparate Freiberg GmbH (TAF), a company of the Pörner Group and specialist in the development of special solutions in plant engineering, introduced its expertise  in the planning, design, construction and manufacture of this pilot plant. The LEPD pilot plant is skid-mounted, thus being transportable and directly useable at the customer’s site. With this test facility, the customer can test his own lube oil formulations on site. The test results obtained can easily be transferred to an industrial plant scale.




Peter Sonntag

Director Sales and Contracting

Tel.: +49 341 4664-308

Fax: +49 341 4664-409