The European NEMESIS 2+ consortium has and successfully tested a pre-commercial on-site system for the production of hydrogen from diesel and biodiesel. The prototype system—the size of a shipping container—can be integrated into existing infrastructure with relative ease.
The prototype, built by the Dutch project partner HyGear, produces 4.4 kilograms of hydrogen from 20 liters of biodiesel per hour—this roughly corresponds to the fuel tank of a B-Class F-cell vehicle. The efficiency of the process, from start to finish, is approximately 70%. (Original project goals were 50 Nm3/h, or 4.5 kg/h with an efficiency >80%.) The EU NEMESIS 2+ project, which ran until June 2015, was coordinated by the German Aerospace Center (DLR).
A techno-economic evaluation, which was also carried out during the EU project, determined maximal production costs of €5.80 per kilogram of hydrogen (US$6.53). This figure is already close to the economic efficiency of the prototype.
In addition to DLR, the project partners included two research facilities, the Centre for Research and Technology Hellas (Greece), and Instituto Superior Técnico (Portugal); three industry partners, Johnson Matthey (United Kingdom), Abengoa Hidrógeno and Abengoa Bioenergía San Roque (Spain), as well as HyGear.
One promising application [for the system] is the production of hydrogen from diesel and biodiesel directly on site at conventional filling stations, which would make it much more convenient to fill up fuel cell vehicles, as well as further support the breakthrough of this technology. The technology developed during the NEMESIS 2+ project could act as a bridge for creating the necessary hydrogen infrastructure, which would enable fuel cell vehicles to be filled up across the country.—Stefan Martin, from the DLR Institute of Engineering Thermodynamics in Stuttgart
Rather than delivering hydrogen within compressed gas cylinders on trucks to filling stations, the NEMESIS 2+ system would use the existing infrastructure for storing and transporting diesel and biodiesel. Compared to pressurized hydrogen, liquid fuels are characterized by their higher volumetric energy density, which makes them easier to transport and store.
|Top: Prototype system. Bottom: Interior of the system. Source: DLR. Click to enlarge.|
The primary form of hydrogen production on an industrial scale has been by natural gas steam reforming. During this process, the hydrocarbons in the gas are converted at high temperature into a hydrogen-rich mixture of gases. The hydrogen is then separated out during an additional process step.
Using steam reforming to produce hydrogen from diesel and biodiesel is more laborious due to the deactivation of the employed catalysts by the deposition of carbon and sulfur impurities on their surface, causing a reduction in the amount of hydrogen produced, Martin explains. With the help of laboratory experiments and simulations, DLR researchers re-examined the entire process systematically, and were able to identify the optimal operating conditions.
This knowledge now allows us to produce high-quality hydrogen with a purity of 99.999 percent, and for the first time, we are able to produce hydrogen from diesel and biodiesel through a process that is stable over a long period.—Stefan Martin
Stefan Martin, Gerard Kraaij, Torsten Ascher, Penelope Baltzopoulou, George Karagiannakis, David Wails, Antje Wörner (2014) “Direct steam reforming of diesel and diesel-biodiesel blends for distributed hydrogen generation” International Journal Of Hydrogen Energy doi: 10.1016/j.ijhydene.2014.10.062