This method was developed, tested and proven at the end of the 1970s by BASF AG and Aral, although conditions at the time were not suitable for profitable operation. In the course of the last 10 years, Clyvia has optimized the method and tested it under laboratory conditions.

In the Clyvia system, the input raw materials are fed into a reactor containing a mixture of circuit oil and a catalyst compound to accelerate the process. A pre-heated liquid and steam mixture is introduced to the reactor, heating the compound to a reactive temperature of approximately 300° C to 400° C. At this point, the longer hydrocarbon molecules crack into shorter hydrocarbon molecules and evaporate.

The evaporated hydrocarbon molecules are then led to a fractional distillation plant which cools the vapor and extracts diesel and/or heating fuel. Separating the distillation component from the reactor component of the plant results in an extremely clean end-product, according to Clyvia.

One hurdle Clyvia has faced is the production of large amounts of undesirable and toxic byproducts, including chlorine, fluorine and coke. The process being developed by Clyvia Technology resolves these issues by binding these substances in the form of salts at temperatures of 260° C to 280° C before the splitting process occurs.

The Clyvia process splits the longer molecules without forming methane, meaning that the Clyvia system does not produce major quantities of coke. The system is different from pyrolytic processes used to split hydrocarbon molecules, which require extremely high reactive temperatures, significantly increasing the cost of the process, and producing high amounts of waste carbon byproduct.

Using a new catalyzing agent, the Clyvia system has been able to maintain constant catalyst activity even in the presence of chlorine and fluorine, which normally interfere with the depolymerization process.

However, in its current stage of development the Clyvia technology does not produce diesel fuel that meets low-sulfur requirements, although it did meet “most” of the fuel parameters required under international fuel standard DIN 51603-1, according to Clyvia’s most recent annual report.

Clyvia management blames additives in the recycled waste oil used as the input material as the source of the excess sulfur. The next round of development and testing—to occur in the new pilot plant—will focus on producing diesel fuels that meet necessary sulfur content requirements.

Earlier this month, the German patent and trade mark office in Munich issued Clyvia a patent (no. 102005010151) for its depolymerization process, as well as for the apparatus needed to realize the process.