Siemens: Algae for Biogas Easily Harvested Using Micrometer Magnetite

Siemens researchers use micrometer magnetic to overcome problems associated with harvesting algae to generate biogas for energy.

 Photo Credit: Siemens

A method developed by Siemens researchers may make it easier to better exploit sources of raw material for biogas plants. Algae can be harvested very easily using the researchers’ method. The researchers were able to demonstrate in the lab that particular fast-growing species of algae accumulate on magnetic particles. The algae, which are used for CO2-neutral combustion, can be harvested as easily as a magnet collects iron nails.

Algae are a valuable source of raw material. For millions of years throughout the history of the world, they have transformed CO2 into valuable organic molecules. Some species specialized in the production of fatty acids and lipids. Their fossilized remains from the dawn of time are the foundation for the petroleum and natural gas extracted today. Algae continue to harbor enormous potential today as suppliers of biomass, biogas, or biodiesel. They are also easy to cultivate. They don’t need anything more than CO2 and water, and preferably wastewater at that because of thenutrients it contains.

Despite all of the advantages, there is one disadvantage: Harvesting the algae has so proved to be particularly difficult. A liter of water contains only a few grams of algae. To harvest it, the water must be drained and filtered in a complex and time consuming process. The new method developed by the Siemens researchers changes all of that. They mix the algae with magnetite. The algae enclose these iron oxide particles, which are only a few micrometers in size – much smaller than the diameter of a human hair. The resulting mixture of algae and magnetite can then be easily extracted using a magnet without having to drain the water.

The new technology offers numerous advantages. Because the water loss is smaller than before, algae also become an interesting source of raw material for drier areas. The algae can also be more efficiently cultivated. The amount of algae harvested can be determined by varying the amount of magnetite used. A certain amount of algae is left behind as the starting stock for the next population.

So far the new technology has only been used on the laboratory scale, but the Siemens researchers are confident that it will also work on a larger scale. The next step would be the construction of a pilot plant for conducting further tests of the scalability and efficiency of the method.

Marine Carbon Nanotube Epoxy Coatings Cut Ship Fuel Consumption by 10%

The Norwegian company Advanced Marine Coatings based in Gamle Fredrikstad specializes in the development of environmentally compatible, heavy-duty anti-corrosion coatings for sea-going vessels is the first company to apply  The “Green Ocean Coating Heavy Duty” coatings which are formulated with Baytubes® carbon nanotubes (CNT) from Bayer MaterialScience. The coating give the ships with them very high abrasion resistance. The coatings also reduce the flow resistance between the ship's hull and the water, thereby enabling a significant reduction in fuel consumption and carbon dioxide (CO2) emissions.

“According to our knowledge, this is the first application of Baytubes® carbon nanotubes in marine coatings”, says Dr. Raul Pires, head of Global Activities for Nanotubes and Nanotechnology Products at Bayer MaterialScience. The coatings are suitable for both new vessels and for subsequent repair and maintenance coatings and reduce fuel consumption by as much as 10%.

The Berge Arzew with “Green Ocean Coating Heavy Duty” Coatings

Photo Credit: Bayer MaterialSceince: The “Green Ocean Coating Heavy Duty” coatings from Advanced Marine Coatings are formulated with Baytubes® carbon nanotubes from Bayer MaterialScience, which gives them very high abrasion resistance. The coatings also reduce the flow resistance between the ship's hull and the water, thereby enabling a significant reduction in fuel consumption that if adopted worldwide could reduce CO2 emissions by 70 million tons.

The Green Ocean Coating Heavy Duty systems are two-component epoxy mastic resins coatings with extremely high resistance to water, making them particularly suitable for marine coatings and in particular for the part of the hull below the surface of the water. Thanks to the addition of Baytubes® carbon nanotubes, these have a very smooth surface and thus help to save fuel and reduce carbon dioxide emissions.

Another major advantage is the reduction of maintenance costs. The ban on organic tin compounds for use as antifouling agents to prevent organic growth has necessitated relative frequent cleaning of the coating surface on the ship’s hull to ensure cost-effective transport. “We hope that the smoothness and greater hardness of the coating will provide better durability and will allow us to extend the cleaning cycle. Thanks to the use of Baytubes®, the systems represent both the most ecological and the most economic solution,” says Stein Dietrichson, Managing Director of Advanced Marine Coatings.

The first ship to be coated with this system was the Berge Arzew, an LNG (liquified natural gas) tanker with a capacity of 138,000 cubic meters. Extensive test coatings of a Green Ocean Coating were successfully applied to a surface area of 700 square meters. The VOC-free system (VOC stands for volatile organic compounds) was applied in film thicknesses of up to 400 micrometers. “The results so far are highly promising. The nanotubes evidently make for a very smooth, pore-free surface,” says Dietrichson.

A film shot in spring 2007 at NTNU and SINTEF Marintek in Trondheim, shows the AMC R & D manager, Eng. Paal Skybak,  who explains about nano modified paints and the Green Ocean development program.
The film is focused on the environment with much attention on CO₂ emissions and how sleek coatings enable energy savings of up to 10%. The consequences of this on a global basis could be a total reduction in CO₂ emissions of more than 70 million tons. This was explained by a Bellona representative, who also said that this will be an important contribution to the effort to improve the global climate by reducing CO2 emissions.
The program may be seen by following this link to: Paint can make ships more environmentally friendly