- Succeeded in manufacturing thin composite palladium membrane with improved stability and economy

- Various applications are expected such as on-site hydrogen station 

■ Recently, the government announced the “Hydrogen Economy Revitalization Roadmap” to  build an industrial ecosystem that can lead the hydrogen economy based on hydrogen cars and fuel cells as two major pillars, and to form economic and stable hydrogen production and supply system. In the course of this, a technology that produces and purifies high purity hydrogen from synthetic gas including natural gas and biomass has been developed by domestic researchers.

○ The currently widely used natural gas-based hydrogen production technology is methane steam conversion method using a catalytic reaction. By steam conversion, methane is converted into a synthesis gas composed of hydrogen and carbon monoxide, and the generated synthesis gas produces high purity hydrogen through separation and purification process such as Pressure Swing Absorption (PSA). However, since the existing methane steam conversion method is operated at a high temperature of 700 to 900℃, it must be composed of a material with excellent heat durability, and because the separation process and the subsequent purification process are separated, a wide installation place and cost are required.

■ Korea Institute of Energy Research (KIER, Director Kwak Byong-sung) combined with hydrogen production methods such as natural gas, biomass, and hydrolysis and succeed in developing the ‘core technology of hydrogen production and purification based on composite  palladium membrane’ that can overcome the problems of existing technologies and efficiently produce and purify hydrogen. 

○ If using the palladium membrane in the existing methane steam conversion method, it is possible to operate at a low temperature of 500 to 550℃, and it can produce high purity hydrogen with higher efficiency by selectively separating and refining hydrogen only in the synthesis gas without additional purification process. In addition, since only hydrogen is separated from the synthesis gas, the remaining carbon dioxide can be more easily collected, thereby contributing to the reduction of greenhouse gases and the spread of environmentally friendly energy.

 ○  The palladium membrane is divided into a foil-type separation membrane and a composite membrane with thin palladium coated on the porous support. The foil-type separation membrane has already been commercialized, but has disadvantages in that the unit price is high because it’s thick and the hydrogen permeability is low. On the other hand, the composite membrane can form thin palladium and it is easy to modularize for application to hydrogen production and purification processes. Thus, the development of this technology is being actively implemented throughout the world. However, coating palladium thin and that transmits only hydrogen without pinhole (microhole) is considered a very difficult technique. 

○ To overcome this, our researchers independently developed the ‘Electroless Plating Method,’ the core of the palladium membrane coating process. Using this technology, the palladium contained in the plating solution can be utilized 99.5% or more, which is about 10% higher than the conventional method, and excellent hydrogen purification is possible even when coated with a thickness of 5 micrometers ro less, which is 3 to 5 times lower than the current palladium foil film. 

■ Ryi Shin-Kun, Principal researcher at the Energy Materials Research Lab, who is in charge of the research, said, “The palladium membrane hydrogen production and purification technology can effectively increase the reaction efficiency by combining with the existing fossil fuel-based hydrogen production method. It can be applied as a key to improving efficiency in the hydrogen production method using future renewable energy and eco-friendly energy sources, and in particular, it is expected to play an important role in the field of on-site supply type high purity hydrogen production and purification.”

○ The researchers will specially secure modularization and system construction technologies to improve the efficiency of palladium membrane-based hydrogen extraction processes. Through this, we plan to standardize on-demand hydrogen purifier applicable to the development of medium and small scale hydrogen plants and electrolysis based on fossil fuels and biomass as well as natural gas and respond to various domestic and international industries.