Newswise — The revolutionary use of ammonia (NH3)* as a fertilizer has greatly benefited human food production. Recently, it has drawn attention again, as the use of green ammonia is considered a significant step forward in developing a hydrogen-focused economy. It serves as a way to transport hydrogen and as a sustainable alternative to fossil fuels.
*Ammonia (NH3): It consists of one nitrogen atom and three hydrogen atoms, showing high compatibility with hydrogen. It becomes liquid at –33℃ under atmospheric pressure, making it easier to store and deliver hydrogen with less energy compared to hydrogen itself. Moreover, ammonia stores 1.7 times more hydrogen per volume than liquid hydrogen, making it suitable for large-scale storage and long-distance transportation of hydrogen. It does not emit carbon, replacing fossil fuels such as coal and natural gas.
Dr. Yoon Hyung Chul and his colleagues at the Clean Fuel Research Laboratory of the Korea Institute of Energy Research (KIER), along with President Yi Chang-keun, develop an advanced catalyst for ammonia synthesis. The catalyst, produced in bulk, has effectively shown its ability to produce 1 kg of pure ammonia (>99.9%) per day at a reduced operational pressure, just one third of the Haber-Bosch* process pressure.
*Haber-Bosch process: ammonia is commercially produced by using an iron-catalyzed reaction of nitrogen from the air and hydrogen extracted from natural gas through pyrolysis. TThe Haber-Bosch process is carried out at high temperatures (over 400℃) and high pressures (over 150 bar). The process was developed in 1909 by German chemists Fritz Haber and Carl Bosch.
The Haber-Bosch process developed in 1909 has been used to produce ammonia through catalytic reaction between hydrogen from fossil fuels and nitrogen from the air at high temperatures and high pressures. This process emits carbon dioxide and consumes a considerable quantity of energy. Hence, an innovative technology is needed to decrease carbon emissions and energy usage. In addition, the technology for producing ammonia is owned by major overseas plants, and the country relies entirely on imported ammonia. This makes the development of new ammonia production technology imperative.
The Korean researchers have surpassed the limitations of the traditional Haber-Bosch process by successfully creating a new catalyst and developing a new method for synthesizing it. They successfully developed a laboratory-scale process to produce 1 kg of ammonia per day at a pressure of 50 bar, resulting in 99.9% pure ammonia.
They partnered with a research team from the Korea Advanced Institute of Science and Technology (KAIST), led by Professor Minkee Choi, to develop a powder-type catalyst made of ruthenium and barium oxide in the form of columnar pellets for commercial use. The catalyst can be synthesized at room temperature, reducing the time for catalyst synthesis to one third of the existing method at 160 ℃, resulting in higher efficiency.
This catalyst's performance was evaluated in the laboratory-scale ammonia production process, the only one of its kind in the country. Ammonia production consists of three parts: the supply section to provide hydrogen and nitrogen, the reaction section for synthesizing ammonia, and the cooling process for extracting highly pure ammonia. The researchers successfully produced ammonia at a low pressure of 50 bar and at temperatures below 400 ℃.
The mass production method for ammonia catalyst and the new design for the ammonia production process developed by researchers are expected to reduce the production cost of ammonia by 15%. Also, the lower pressure from the traditional method can reduce the cost of pressurizers and reactors, resulting in an overall reduction in the total cost of ammonia production.
Dr. Yoon Hyung Chul states that using low pressure, low temperature, and low-cost technology for ammonia production will be crucial to achieving carbon neutrality as soon as possible. Also, this technology will significantly contribute to the construction of ammonia production plants for green hydrogen and carbon-free fuels in Korea.
The researchers plan to operate the ammonia production process throughout the year 2024, ensuring long-term operational stability. They also aim to redesign the production process to produce 5 kg per day. They also plan to construct a pilot demonstration for producing 50 kg per day, which will position the country as a producer of green ammonia.
Funding for this research breakthrough has been granted by both KIER and the Ministry of Oceans and Fisheries as part of the ministry’s eco-friendly ship all-life innovative R&D project.
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