KIER has achieved a historic milestone in Korea by successfully producing ultrapure hydrogen from ammonia and completely eliminating carbon dioxide emissions in the process.

Dr. from the Hydrogen Research Department of the Korea Energy Research Institute (KIER). Jung Unho’s research group developed Korea’s first clean hydrogen production technology. This innovative approach is based on the decomposition of ammonia and does not use fossil fuels. The team’s breakthrough could pave the way for a more sustainable and green energy source. This makes it possible to produce high-purity hydrogen that meets international standards for hydrogen-powered vehicles, without the carbon dioxide emissions from the use of fossil fuels.

Ammonia, a compound composed of hydrogen and nitrogen, has a hydrogen storage density 1.7 times greater than liquid hydrogen and stands out as the most cost-effective way to transport hydrogen. Since it has been used in various fields such as fertilizer for more than 100 years, it is equipped with infrastructure, transportation and security standards. This is considered the most practical solution to solve the problems of storing and transporting hydrogen.

Pure hydrogen production process

Ammonia consists only of hydrogen and nitrogen, so carbon is not released when hydrogen is removed. The decomposition process requires thermal energy input of over 600 °C and currently uses fossil fuels, resulting in carbon dioxide emissions. Therefore, for the production of pure hydrogen, it is necessary to use an energy source that does not contain carbon, even during the decomposition of ammonia.

By using the small amounts of hydrogen and ammonia left over from the decomposition reaction, researchers were able to produce hydrogen without using fossil fuels.

To obtain pure hydrogen from ammonia, the decomposition of ammonia is carried out at a temperature above 600 ° C using a ruthenium (Ru) catalyst, followed by hydrogen purification using pressure adsorption (PSA) technology. During the application of this method, a residual gas mixture of nitrogen and hydrogen is created, which is used as the heating element for the ammonia cracking reactor. Even so, residual gas alone cannot provide sufficient reaction heat, so additional heat must be added.

Overcome challenges with innovative solutions

In current technology, insufficient reaction heat is supported by fossil fuels such as natural gas (LNG) or liquefied petroleum gas (LPG) and carbon dioxide is released during combustion. However, thanks to the system developed this time, it is possible to capture the reaction heat and prevent carbon dioxide emissions at the source by feeding ammonia instead of fossil fuels.

Using the developed system, high purity hydrogen of over 99.97%, which can be fed into the fuel cells of hydrogen electric vehicles, is produced at a rate of 5 Nm3 (approximately 0.45 kg) per hour. Additionally, the hydrogen produced has an impurity concentration of less than 300 ppm for nitrogen and less than 0.1 ppm for ammonia. It was compliant with ISO 14687, the international standard for hydrogen-powered electric vehicles.

A research team has achieved a major milestone by demonstrating a 1kW fuel cell system for buildings that produces carbon-free electricity using hydrogen produced from ammonia. This demonstration, carried out in collaboration with Doosan Fuel Cell Power BU (unit), is important in overcoming the problem of carbon dioxide emissions, which is considered a disadvantage of natural gas (LNG) fuel cell systems. This demonstrates the potential of electricity generation using clean hydrogen fuel cells.

Chief investigator Dr. According to Jung Uno, the newly developed technology is important because it fills previous gaps in this field by allowing carbon-free hydrogen production using ammonia. It is expected to find practical applications in various fields where pure hydrogen is used. He continued: “The combination of ammonia and fuel cells is a viable option for powering green ships. “By scaling up, we can also make a significant impact on the clean hydrogen energy sector.”