Clariant, Haltermann and Mercedes-Benz have fleet-tested high-octane sunliquid 20 fuel—containing 20% cellulosic ethanol produced from straw—since January. (Earlier post.) The test found that the use of sunliquid 20 improves engine efficiency—more than compensating for its 4% lower energy content compared to E10. For drivers, this means with sunliquid 20, CO2emissions are reduced while consumption remains the same.
Use of sunliquid 20 also resulted in a 50% improvement in particle emissions count in contrast to the EU 5 reference fuel. The cellulosic ethanol in sunliquid 20 demonstrates greenhouse gas emission savings of up to 95% across the entire value chain (well-to-wheel perspective) without competing with food production or agricultural acreage.
Cellulosic ethanol from agricultural residues can play a key role in creating more sustainable mobility in Germany, Europe and worldwide. Here we have the latest generation of truly advanced biofuel, the high performance of which was confirmed in the fleet test on series vehicles. Second generation biofuels coming from agricultural residues are now technologically ready and available for production and application. A change in energies used for transport must also be successful now; for this to happen, we urgently need stable framework conditions such as the mandatory blending rate for advanced biofuels being discussed at EU level.—Professor Andre Koltermann, Head of Group Biotechnology at Clariant
Our main task is to shape solutions to create sustainable mobility for the future. Gasoline with 20% ethanol can already be used easily in our latest Mercedes-Benz BlueDIRECT gasoline engines. The prior experiences from the pilot project are optimistic, as are greenhouse gas emission savings regarding efficiency. Hence cellulosic ethanol can make a significant contribution to climate protection, so making it for us a building block of sustainable mobility.—Peter Lueckert, Director for Engine, Powertrain, and Fuel Injection, Daimler AG
|sunliquid process. Click to enlarge.|
sunliquid 20 is an E20 fuel with 20% cellulosic ethanol. Wheat straw or other non-edible agricultural residues are converted into cellulosic ethanol using Clariant’s sunliquid process.
During the fully integrated sunliquid process, highly optimized, feedstock-specific biocatalysts split cellulose and hemicellulose into fermentable sugars with high yields under stable process conditions. The process-integrated production of biocatalysts offers flexibility and reduces production costs.
In the next step, an optimized fermentation organism allows both C5 and C6 sugars to be converted into ethanol, thus increasing the ethanol yield by around 50%. A novel purification process developed by Clariant is instrumental in enabling all the energy required for the process to be derived from the insoluble residue lignin.
The resulting cellulosic ethanol saves around 95% of CO2 emissions when compared to fossil gasoline.
Haltermann then mixes the cellulosic ethanol with conventional fuel components to form sunliquid 20. The 20% cellulosic ethanol gives the fuel a high octane number (RON) of more than 100.
In January 2014, Clariant, Haltermann, and Mercedes-Benz began the fleet test with Mercedes-Benz series vehicles. The test fleet vehicles can be refilled with the new fuel at a specially equipped gas station on the Mercedes-Benz site in Stuttgart-Untertürkheim for one year.
The cellulosic ethanol comes from Clariant’s sunliquid demonstration plant in Straubing, where approximately 4,500 tons of agricultural residues such as wheat straw or corn stover are converted into cellulosic ethanol each year. At the Haltermann plant in Hamburg, the bioethanol is mixed with selected components to create the innovative fuel, the specifications of which reflect potential European E20 fuel quality.