Gaseous Hydrocarbon Synfuels from Renewable Electricity via H 2 /CO 2 -Flexibility of Fixed-Bed Catalytic Reactors

The increased generation of renewable electricity (wind, solar), due to its fluctuating characteristic, leads to an increasing storage demand. A potential storage technology is the conversion of electrical energy into chemical energy (e.g. in form of gaseous hydrocarbons), which can be easily stored and distributed in an existing natural gas grid. CO 2 is the C-source of choice, from biogas plants or industrial processes, making possible the production and use of C-based fuels without increasing the CO 2 emissions into the atmosphere. The combination of Fischer–Tropsch synthesis and CO 2 shift reaction, using iron-based catalyst, offers the possibility to produce substitute natural gas (SNG) components from CO 2 . Due to the fluctuating nature of hydrogen production from renewable electrical energy, advantages can be identified if the chemical reactor is operated under variable load conditions. The aim of the present study is to evaluate the flexibility of a catalytic synthesis reactor as a potential component in a future energy system with a high contribution of renewable energy. The hydrogenation of CO 2 to gaseous components is studied in a fixed-bed lab-scale reactor to determine kinetic parameters and hydrocarbon product distribution. Results from the experimental work are implemented in the mathematical model and are the basis for the conceptual design of the catalytic fixed-bed reactor able to operate under variable load conditions.