Hydrogen march
Engineers are working on new methods with which to produce hydrogen economically and environmentally friendly.
Who's going to René Müller on the premises of Linde AG, gets a feel for how the balance of power could shift in the future. The first view is of a giant oven, large as an office building, entwined by innumerable tubes and valves. "Our steam reformer," says Müller. "The plant makes 35,000 cubic meters of hydrogen - an hour." The disadvantage: The raw material for the system is natural gas, which is a fossil fuel. Then the manager reveals three nondescript container next to the colossus. "Our pilot plant creates only about 50 cubic meters of hydrogen. But this hydrogen is green." For feedstock is vegetable glycerin, which falls in the production of biodiesel. The new technique, developed by Linde in Leuna, could one day provide hundreds of thousands of fuel cell vehicles with environmentally-friendly fuel.
Industrial hydrogen is currently produced from natural gas. It is used as an adjuvant for oil refineries, chemical companies and paper manufacturers. But the gas is also considered a potential fuel for future cars. If you use it in a fuel cell, nothing is as pure water vapor from the exhaust. However, the concept is just beginning: So far, in order to test operation only about a hundred fuel cell cars roll by Germany, most of them based on the Mercedes B-Class. By 2014, Daimler is targeting to mass production. The drawback: Today, the majority of the hydrogen is produced from natural gas, and it will release CO2. Climate-neutral fuel would be, he would produce green - ie using renewable energies. Until now, the scientific community is to primarily to the electrolysis of water. The principle: An existing ultrafine membranes electrolyzer splits water molecules into its components oxygen and hydrogen. The required energy comes from wind turbines, solar and hydroelectric power plants. The technology is expensive, green hydrogen will cost significantly more than conventional.
Therefore, an alternative test Linde: With its Leunaer pilot plant, the company generated since last autumn not the hydrogen electrically but chemically. Base is glycerin obtained during the production of biodiesel - as much as 100 kilograms per tonne of biodiesel. Every year in Germany come together around 250,000 tons crude glycerine. Only a small part is in the pharmaceutical industries and the rest ends up in biogas plants or is otherwise disposed of.
René Müller opens the door to the largest of the three containers - the heart of the pilot plant. Two head-high, blue-painted tons dominate the room and heat it on chubby temperatures. "These are ovens where it is up to 840 degrees Celsius," says Müller. Through a peephole glowing red coils are visible. In this glow squeeze pump a mixture of water vapor and prepurified crude glycerine. Within seconds, the gas passes through the hot tubes, a cocktail out more than one part of a complex hydrocarbon compounds.
This mixture is passed into the second furnace. Here a catalyst splits the molecules into simpler compounds: methane, carbon monoxide, CO2 - and 66 percent hydrogen. The methane can be recovered after the removal of the hydrogen, to fuel the furnaces around the plant. "Since many development hours put in there," says Mueller. "The gases must not remain too long in the oven, otherwise forms soot that clogs the system." At the end of the hydrogen is purified and transported to gas stations in Berlin and Hamburg. "The experience is good, the technical feasibility has been demonstrated."
According to a New analysis, the new method can in the commercial large scale compared to fossil-generated hydrogen can save up to 80 percent of CO2 emissions. 50 kg per hour flow glycerol by the prototype. Out, four kilograms of hydrogen - a tank of gas for a fuel cell car with a 400 kilometer range. Theoretically could be with the 250,000 tonnes of glycerine that occur annually in the production of biodiesel, driving 200,000 fuel cell cars. "We could also use other types of glycerin that occur in the industry as a waste product," says René Müller. "So we are thinking about a series of experiments with fish oil." The next step is ten times larger demonstration plant is planned. Ready for deployment on a large scale, however, the process is likely to be some years before. One thing is clear: The larger the plant would be more efficient they would be working. "At what cost of hydrogen will be produced, can be present but not yet say," says Müller.
The major disadvantage of the method: Its potential is limited, there is simply not enough glycerin to make millions of cars driving it. Therefore, engineers continue to work on the electrolysis of water. Last October, the energy company Enertrag inaugurated in Prenzlau the world's first hydrogen-hybrid power plant: three rotors dine excess wind power to an electrolyzer that produces hydrogen and stores it in tanks. Some of the gas is in a lull converted back into electricity, the rest transported to a hydrogen filling station in Berlin.
"The tests were positive, now the system is running in continuous commercial operation," said board member Werner Enertrag Diwald. "Since April, we deliver every two weeks 200 kg hydrogen to Berlin." Until hydrogen production on a large scale is still a lot of distance to cover. To supply one million fuel cell cars, it would take about 1,000 turbines in the 2.5-megawatt class.
The second obstacle is the current price. "We can make hydrogen from wind power for eight to nine euros per kilo," says Diwald. Using optimized technology, the sum could certainly drop to six or seven euros. Would be added but still taxes and distribution costs, so that the driver of a hydrogen fueling station would shell out around 15 euros for pounds, with which he can go 100 kilometers. Diwald is convinced: "From 2025 is expected to be highly competitive as diesel and gasoline will likely cost more than two euros per liter."
Similarly, does the calculation in another production method for green hydrogen - the production of solar energy. In early March, the Fraunhofer Institute for Solar Energy Systems ISE in Freiburg inaugurated a solar-powered hydrogen refueling station. Not only is the gas station roof, but also two neighboring buildings are plastered with solar panels. Together, they provide up to 50 kilowatts and feed an electrolyzer, the day delivers twelve kilograms of hydrogen.
If one were using solar power to drive a million fuel cell cars you would have the same number of single-family homes solar screws. Their power would then only be used for hydrogen production. But that is not the vision of the experts: "It is the stated goal of one day generate all the electricity in Germany regenerative" says ISE researchers Christopher Hebling. "Then you would have to not provide the current for the green by hydrogen alone solutions, but it could easily take off the grid."
At the network nodes would stand thousands of electrolyzers which generate always hydrogen when rotors and solar cells provide more power than currently required. Of these electrolyzers will depend a lot: Because the water splitter are still too expensive and often can only be realized as a small plant. Marketable to the technology, is the glycerol method of Linde - despite all the quantitative restrictions - may play an important role. Towards the end of the decade it could well be in a position to supply more than one hundred thousand fuel cell cars with affordable hydrogen.
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