This could lead to hydrogen as an energy carrier: Fraunhofer researchers have discovered a new way to convert hydrogen into methanol – without causing any major energy losses. This can greatly simplify storage and transportation.
The new methanol rectifier is significantly smaller than the previous models.
Photo: Fraunhofer IMM
Hardly a day goes by without announcing new developments on the subject of hydrogen, and with good reason: its potential for energy transitions is enormous. And indeed, concentrated efforts are leading to more and more innovations that will probably soon make an environmentally friendly energy source suitable for everyday use in many fields – the Fraunhofer Institute for Microtechnology and Microsystems (IMM) has now developed a new methanol reformer is presented. Intended for mobile use and puts its predecessors in the shadows.
Climate-neutral conversion of hydrogen to methanol
Of course, the idea of converting hydrogen to methanol is not new. Methanol is very easy to transport and above all, can be stored for a long time. In other words: it would be possible, for example, to produce hydrogen using electricity from solar systems using the electrolysis process, then convert it to methanol and bring it to areas where the energy requirement is covered by solar energy. cannot be done. The carbon dioxide needed for methanol production can be taken from the atmosphere. An alternative would be, for example, the use of power plant gases (carbon dioxide capture). This means that the bottom line is that it will be possible to make the process climate-neutral. Because the CO2, which is released when methanol is converted back to hydrogen, was previously removed from the atmosphere.
Experts are sure: in 10 years the hydrogen car will be back to normal
By extension, a methanol reformer is needed, which requires additional steam so that the methanol becomes hydrogen – and carbon dioxide. With a mobile rectifier, it can also be directly in the car. So far, what seems so practical has been associated with many problems in practice. On the one hand, catalysts are needed for the respective reactions. These are usually pellets of pressed copper zinc oxide powder that go into the reactor. However, their friction soils the fuel cell. Moreover, the whole process is very slow. but that’s not all. Because the process loses a lot of efficiency the steam reforming reaction only works with heat. A lot of energy is lost here and at other interfaces.
New catalysts and sizes for greater efficiency in hydrogen conversion
Scientists at the Fraunhofer IMM have now largely mastered these challenges. An important building block was improved catalyst technology. “We rely on catalytic coatings containing precious metals that do not cause any friction – similar to automotive catalysts,” says Gunther Kolb, deputy institute director and division head at Fraunhofer IMM. “Therefore, less catalyst material is required. Since our catalyst material also has high activity, the required catalyst mass falls again as the cost.” It has another advantage. As with conventional rectifiers, by-products such as carbon monoxide are generated when the system is not used to capacity. That’s not the case with their new methanol reformer, the researchers say.
The next point is thermal management. Ultimately, the conversion of hydrogen to methanol and back to hydrogen must also be efficient in order to be able to make better use of the energy carrier. Scientists have actually put into practice a very simple idea and changed the structure of the reformer. First they coated plate heat exchangers with catalytic material and made stacks of up to 200 plates. If the gas now flows over it, it is in contact with the catalyst on one side and can be thoroughly heated in small channels on the other. In addition, the researchers use waste heat, which makes the system overall very efficient.
The illustration shows the simple principle of a methanol rectifier. Hydrogen could be stored by this rotation.
Photo: Fraunhofer IMM
Prototype of methanol reformer suitable for series production
This sounds like a future proof methanol reformer that could play a major role in hydrogen applications. The best thing about it: It requires just 17% less replacement than traditional rectifiers. The researchers are currently working on a prototype that should be ready in a few months. “The project is designed to be long-term, and various prototypes are being integrated into land vehicles as a test run,” Kolb says. He also has alternative materials in mind so that the reformers can weigh less for hydrogen storage over the long term – they are currently made of steel. According to Kolb, even light substances are perceptible.
Incidentally, according to the researchers, the production can be compared with the manufacture of high-pressure heat exchangers for motor vehicles. So nothing stands in the way of chain building.
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