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Germany: Renewable Energy Converting Waste into Fuel

| Editor: Alexander Stark

Scientists at the Technical University of Munich have developed a method that could make the production of fuel from waste economically viable.

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Model of the zeolithe catalyst
Model of the zeolithe catalyst
(Source: Andreas Heddergott / TUM)

Munich/Germany — Until now, converting organic waste to fuel has not been economically viable. Excessively high temperatures and too much energy are required. Using a novel catalyst concept, researchers at the Technical University of Munich (TUM) have now managed to significantly reduce the temperature and energy requirements of a key step in the chemical process. The reaction takes place in very confined spaces inside zeolite crystals.

Ever more electricity is produced decentrally using wind, hydro and solar power plants. “It thus makes sense to decentralize chemical production, as well,” thinks Prof. Johannes Lercher, who heads the Chair of Technical Chemistry II at TU Munich. “Theoretically, any municipality could produce its own fuel or fertilizer.”

To date, this has not been possible because chemical processes require a great deal of energy — more than local renewable energy sources can provide. “We thus aimed at findinding new processes to lay the foundations for the distributed production of chemicals, which can be powered using renewable energy sources,” explains the chemist, who is also Director of the American Institute for Integrated Catalysis at Pacific Northwest National Laboratory.

His team has now fulfilled one prerequisite for a turnaround in chemical production: In the laboratory, the scientists demonstrated that the temperature required for splitting carbon-oxygen bonds in acidic aqueous solution can be drastically reduced using zeolite crystals. The process also ran much faster than without the zeolite catalysts.


“Our experiments demonstrate that zeolites as catalysts are similarly effective as enzymes: Both significantly reduce the energy levels required by the reactions,” reports Lercher. “The smaller the cavity, the larger the catalytic effect. We achieved the best results with diameters far below one nanometer.”

From Garbage to Fuel

When they come into contact with hydronium ions, organic molecules such as alcohols lose oxygen. This makes the process suitable to converting bio-oil obtained from organic waste into fuel.

“We are still working on the fundamentals,” emphasizes Lercher. “We hope to use these to create the conditions required for new, decentral chemical production processes that no longer require large-scale facilities.”