Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Lubricant for oil tankers

24.01.2019

If ship hulls were coated with special high-tech air trapping materials, up to one percent of global CO2 emissions could be avoided. This is the conclusion reached by scientists from the University of Bonn together with colleagues from St. Augustin and Rostock in a recent study. According to the study, ships could save up to 20 percent of fuel as a result of reduced drag. If so-called antifouling effects are also considered, such as the reduced growth of organisms on the hull, the reduction can even be doubled. The study has now been published in the journal “Philosophical Transactions A”.

Ships are among the worst fuel guzzlers in the world. Together, they burn an estimated 250 million tonnes per year and emit around one billion tonnes of carbon dioxide into the air - about the same amount as the whole of Germany emits over the same period.


The aquatic fern Salvinia molesta traps underwater in a thin layer of air, which it can hold for many weeks.

© Prof. Dr. Wilhelm Barthlott/Uni Bonn


Scanning electron microscope image of a surface that is modeled on that of Salvinia.

© Prof. Dr. Wilhelm Barthlott/Uni Bonn

The main reason for this is the high degree of drag between hull and water, which constantly slows the ship down. Depending on the type of ship, drag accounts for up to 90 percent of energy consumption. This also makes it a huge economic factor: After all, fuel consumption is responsible for half of transport costs.

Drag can be significantly reduced using technical tricks. For example, the so-called “microbubbles technology” actively pumps air bubbles under the hull. The ship then travels over a bubble carpet, which reduces drag. However, the production of the bubbles consumes so much energy that the total savings effect is very small.

Coatings retain air for weeks

Novel high-tech coatings may promise a solution. They are able to hold air for long periods of even weeks. “Around ten years ago, we were already able to demonstrate on a prototype that in principle it is possible to reduce drag by up to ten percent,” explains Dr. Matthias Mail from the Nees Institute for Biodiversity of Plants at the University of Bonn, one of the authors of the study. “Our partners at Rostock University later achieved a 30-percent reduction with another material developed by us.”

Since then, various working groups have taken up the principle and developed it further. The technology is not yet mature enough for practical use. Nevertheless, the authors forecast a fuel-saving potential of at least five percent in the medium term, but more likely even 20 percent.

In their publication in the renowned “Philosophical Transactions” of the British Royal Society, founded by Isaac Newton, they calculated the economic and ecological advantages this would bring. For example, a commercial container ship on its way from Baltimore (USA) to Bremerhaven could reduce its fuel costs by up to 160,000 US dollars. Worldwide, emissions of the greenhouse gas carbon dioxide would be reduced by a maximum of 130 million tonnes.

Taking into account the reduced growth of barnacles and other aquatic organisms, which causes enormous additional drag loss, this quantity even rises to almost 300 million tonnes. This corresponds to almost one percent of global CO2 emissions. “Of course, these figures are optimistic,” says Mail. “But they show how much potential this technology has.”

Hydrophobic floating fern

The high-tech layers are based on models from nature, such as the floating fern Salvinia molesta. This is extremely hydrophobic: When submerged and pulled out again, the liquid rolls off it immediately. After that, the plant is completely dry.

Or to be more accurate: It was never really wet in the first place. Because underwater the fern wraps itself in an extremely thin dress of air. This prevents the plant from coming into contact with liquid - even during a many weeks-long dive. Scientists call this behavior “superhydrophobic”.

Salvinia has tiny egg-beater-like hairs on the surface of its leaves. These are water-repellent at their base, but hydrophilic at their tip. With these hair-tips, the aquatic fern firmly “pins” a water layer around itself. Its little dress of trapped air kept in place by the water layer. Perhaps this principle will soon cause a sensation in a completely different context: as a potent lubricant for oil tankers.

Wissenschaftliche Ansprechpartner:

Prof. Dr. Wilhelm Barthlott
Nees-Institut für Biodiversität der Pflanzen
University of Bonn
Tel.: +49 (0)228-73 2271
E-mail: barthlott@uni-bonn.de

Originalpublikation:

J. Busch, W. Barthlott, M. Brede, W. Terlau, M. Mail: Bionics and green technology in maritime shipping: an assessment of the effect of Salvinia air-layer hull coatings for drag and fuel reduction. Phil. Trans. R. Soc. A 377: 20180263. http://dx.doi.org/10.1098/rsta.2018.0263

Johannes Seiler | idw - Informationsdienst Wissenschaft
Further information:
http://www.uni-bonn.de/

More articles from Studies and Analyses:

nachricht How to design city streets more fairly
18.05.2020 | Mercator Research Institute on Global Commons and Climate Change (MCC) gGmbH

nachricht Insects: Largest study to date confirms declines on land, but finds recoveries in freshwater – Highly variable trends
24.04.2020 | Deutsches Zentrum für integrative Biodiversitätsforschung (iDiv) Halle-Jena-Leipzig

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Small Protein, Big Impact

In meningococci, the RNA-binding protein ProQ plays a major role. Together with RNA molecules, it regulates processes that are important for pathogenic properties of the bacteria.

Meningococci are bacteria that can cause life-threatening meningitis and sepsis. These pathogens use a small protein with a large impact: The RNA-binding...

Im Focus: K-State study reveals asymmetry in spin directions of galaxies

Research also suggests the early universe could have been spinning

An analysis of more than 200,000 spiral galaxies has revealed unexpected links between spin directions of galaxies, and the structure formed by these links...

Im Focus: New measurement exacerbates old problem

Two prominent X-ray emission lines of highly charged iron have puzzled astrophysicists for decades: their measured and calculated brightness ratios always disagree. This hinders good determinations of plasma temperatures and densities. New, careful high-precision measurements, together with top-level calculations now exclude all hitherto proposed explanations for this discrepancy, and thus deepen the problem.

Hot astrophysical plasmas fill the intergalactic space, and brightly shine in stellar coronae, active galactic nuclei, and supernova remnants. They contain...

Im Focus: Biotechnology: Triggered by light, a novel way to switch on an enzyme

In living cells, enzymes drive biochemical metabolic processes enabling reactions to take place efficiently. It is this very ability which allows them to be used as catalysts in biotechnology, for example to create chemical products such as pharmaceutics. Researchers now identified an enzyme that, when illuminated with blue light, becomes catalytically active and initiates a reaction that was previously unknown in enzymatics. The study was published in "Nature Communications".

Enzymes: they are the central drivers for biochemical metabolic processes in every living cell, enabling reactions to take place efficiently. It is this very...

Im Focus: New double-contrast technique picks up small tumors on MRI

Early detection of tumors is extremely important in treating cancer. A new technique developed by researchers at the University of California, Davis offers a significant advance in using magnetic resonance imaging to pick out even very small tumors from normal tissue. The work is published May 25 in the journal Nature Nanotechnology.

researchers at the University of California, Davis offers a significant advance in using magnetic resonance imaging to pick out even very small tumors from...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Dresden Nexus Conference 2020: Same Time, Virtual Format, Registration Opened

19.05.2020 | Event News

Aachen Machine Tool Colloquium AWK'21 will take place on June 10 and 11, 2021

07.04.2020 | Event News

International Coral Reef Symposium in Bremen Postponed by a Year

06.04.2020 | Event News

 
Latest News

Why developing nerve cells can take a wrong turn

04.06.2020 | Life Sciences

The broken mirror: Can parity violation in molecules finally be measured?

04.06.2020 | Physics and Astronomy

Innocent and highly oxidizing

04.06.2020 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>