In Rapperswil, the researchers and developers of the former HSR University of Applied Sciences Rapperswil, are producing methane (CH 4 ) in a catalytic methanation process by converting the carbon dioxide (CO 2 ) and hydrogen (H 2 ), using a nickel-based catalyst. The resulting heat is used immediately within the system so that the primary energy used can be used more efficiently. Further increases in efficiency are now the main focus in the further development of the HEPP ( High Efficiency Power-to-Methane Pilot) system.
The project team is currently working on the integration of a high-temperature electrolysis (also known as SOE “Solid Oxide Electrolyzer”), which is operated at around 700 ° C. Thanks to the very high temperature, this technology enables a high degree of efficiency in the conversion of water (vapor) to hydrogen, so that the efficiency of the entire process can be increased from 55 percent today to around 70. In the HEPP plant in Rapperswil, the technology is being transferred from laboratory to pilot scale. “With our system, we want to demonstrate the technology in an industrial environment and answer relevant questions,” explains project engineer Luca Schmidlin. “We also want to increase the maturity of this technology. The test takes place in small format with an output of around 10 kilowatts, but under real conditions. "
The group is also carrying out the first test campaign for the operation of an "SEM" reactor. The so-called “Sorption-Enhanced Methanation” (SEM) or sorption-supported methanation has clear advantages compared to conventional methanation approaches: on the one hand, through the generation of pure, dry methane in one step and, on the other hand, through an improved reaction rate. “The water that arises during methanation is separated on site. This leads to dry, synthetic methane as a product at the reactor outlet. The separation of water also shifts the chemical equilibrium according to the Le Chatelier principle, and the hydrogen used is fully converted and thus, in turn, greater efficiency, ”explains Schmidlin.
New sulfur-insensitive catalyst systems that allow the use of biogas will also be integrated into the HEPP system and tested. Biogas is a possible source of CO 2 , but it also contains impurities (especially hydrogen sulphide) which destroy conventional catalysts even in small amounts. “In addition to the effective integration of the HEPP system into the gas and electricity network, we show with our in-house SNG / biogas filling station that SNG is part of the mobility solutions, for example for refueling CNG vehicles. The methane produced in the HEPP system can be used to supply the integrated CNG filling station or fed to the Energie Zürichsee Linth pressure reducing station , where it is fed into the local gas network.