The European Union (EU) will ban the sale of internal combustion engine vehicles using gasoline or diesel fuel from 2035. However, new vehicles using E-Fuel fuel are an exception. In the midst of this, a microchannel reactor that produces E-Fuel close to diesel has been developed for the first time in Korea, and it is expected to be used as an innovative technology in various fields that can control heat, such as ammonia synthesis, in addition to responding to international fuel regulations in the future and producing E-Fuel.

The research team of Kim Young, a senior researcher at the Heat Pump Research Center of the Carbon Neutral Machinery Research Institute of the Korea Institute of Machinery and Materials (President Ryu Seok-hyun, hereinafter referred to as KIMM), developed a high-efficiency microchannel reactor that can reduce the amount of catalyst required for e-fuel production by 30% and has 30 times the capacity of existing reactors. This reactor is safe at high temperature and high pressure, has easy heat removal, and has flexible temperature settings, making it advantageous for fuel production.

E-Fuel is expected to be a clean fuel that will contribute to reducing carbon emissions in the transportation sector as it is produced by combining green hydrogen produced through electrolysis using renewable electricity and carbon dioxide captured from the air.

To produce e-fuel, green hydrogen and carbon dioxide must be synthesized in a process that generates a lot of heat, so a key technology to effectively remove the heat is needed.

The reactor developed by the Korea Institute of Machinery and Materials was designed and manufactured with a structure that has excellent heat generation control performance even at high temperatures by bonding plates with a microchannel structure stacked one on top of the other using a high-temperature method rather than adhesive.

The e-fuel produced through the reactor developed by the research team has a cetane index of 55.7, which satisfies the cetane index quality standard of 52 or higher for domestic vehicle diesel.

This is equivalent to the cetane number of 54-57 of diesel sold by domestic oil refineries.

The cetane index is a measure of the combustion performance of diesel fuel, and is a measure of how easily the fuel ignites in a diesel engine. The higher the cetane index, the faster and more easily the fuel ignites in the engine.

In the past, when heat generation was high during the fuel synthesis process, slurry reactors or fluidized bed reactors were used, but these were effective for large-scale production. On the other hand, the amount of hydrogen produced from surplus electricity in distributed regenerative power plants is small, so applying a large reactor has the disadvantage of lowering economic feasibility and efficiency.

The research team developed a small-sized, highly efficient microchannel reactor based on existing microchannel heat exchanger technology, and confirmed that 93% of the synthesis gas was converted into fuel in the fuel synthesis reaction. In the future, if a high-efficiency e-fuel production process in the size of a container is developed, it is expected that the possibility of eco-friendly gas stations that can use e-fuel will open up.

Kim Young, a senior researcher at the Korea Institute of Machinery and Materials, said, “This is a technology that can quickly respond to changes in the supply of irregular renewable power sources such as solar and wind power because of its excellent thermal control performance.” He added, “In the future, when there is an oversupply of renewable power, this technology will contribute to increasing the economic feasibility of renewable power generation and improving the stability of the power grid.”

Meanwhile, this study was conducted with the support of the Korea Institute of Machinery and Materials' basic project 'Development of Micro Channel Reactor for Power to Fuel System'.