Fraunhofer researchers have discovered a new method for converting hydrogen to methanol that involves minimal energy waste. This has the potential to considerably simplify storage and transportation.
Almost every day brings news of new advances in the field of hydrogen, and for good reason: its potential for the energy transition is huge. And indeed, concentrated efforts are resulting in an increasing number of innovations that will likely soon make the environmentally friendly energy carrier practical for everyday use in a wide variety of applications – the Fraunhofer Institute for Microtechnology and Microsystems IMM has recently unveiled a new methanol reformer designed for mobile applications that blows away its predecessors.
Conversion of hydrogen to methanol in a climate-neutral manner
Of course, the concept of hydrogen conversion to methanol is not novel. Methanol is significantly easier to transport and, more importantly, to store for an extended period of time. In other words, it would be able to use solar energy to generate hydrogen by electrolysis, then convert it to methanol and transport it to locations where solar energy cannot meet the energy requirement. Carbon dioxide, which is required for the synthesis of methanol, might be taken from the environment. For instance, one alternative would be to utilize power plant emissions (carbon dioxide capture). The final line is that the process might be made climate neutral. This is because the CO2 emitted during the conversion of methanol back to hydrogen was previously removed from the atmosphere.
To be more specific, a methanol reformer is required, which utilizes additional water vapor to convert the methanol to hydrogen – and carbon dioxide. This can even occur directly in a car when using a mobile reformer. What appears to be a reasonable solution has proven to be laden with complications in practice. Catalysts, for example, are required for the appropriate reactions. Typically, these are pellets of crushed copper-zinc oxide powder delivered into the reactor. Their abrasion, on the other hand, contaminates the fuel cell. Additionally, the entire process is far too slow. However, it is not all. Due to the steam reforming reaction’s reliance on heat, the process loses a significant amount of efficiency. A significant amount of energy is lost at this and other interactions.
Catalysts and molds for increased hydrogen conversion efficiency
Fraunhofer IMM scientists have now overcome the majority of these obstacles. A critical building block in this case was improved catalyst technology. “We rely on catalyst coatings comprising precious metals that do not abrade – comparable to the catalytic converter in a car,” explains Gunther Kolb, the institute’s deputy director and division manager at Fraunhofer IMM. “As a result, less catalyst material is required. Additionally, because our catalyst materials have a higher activity, the necessary catalyst mass and costs decrease.” This also has an advantage. When a typical reformer is underutilized, he explained, byproducts like as carbon monoxide are created. That is not the case, the researchers assert, using their novel methanol reformer.
The following concern is thermal management. After all, the conversion of hydrogen to methanol and back to hydrogen must be efficient as well in order to maximize the energy carrier’s efficiency. To do this, the scientists modified the design of the reformer, which is a rather straightforward concept. They began by coating plate heat exchangers with the catalyst material and stacking them up to 200 plates high. When the gas passes through them, it makes contact with the catalyst and is heated in the narrow channels. Additionally, the researchers utilize waste heat, which results in a highly efficient system overall.
Methanol reformer prototype suitable for series manufacture
This appears to be a future-proof methanol reformer that has the potential to play a significant role in hydrogen applications. Best of all, it has a footprint of only 17% of that of conventional reformers. The researchers are currently developing a prototype, which should be available in a few months. “The project is intended to be long-term in nature, with several prototypes being integrated onto land vehicles for testing purposes,” Kolb explains. He is also investigating alternate materials to reduce the weight of reformers used for hydrogen storage in the long run – they are now composed of steel. However, according to Kolb, lightweight materials are also a possibility.
