To investigate the properties of the process and identify an operation window, parameter variations are carried out. In case of SPO a variation of the H2/CO2 ratio, 3.5 ≤ 𝑟 in ≤ 5.5, at the reactor inlet (stream (in)) is conducted as well as a variation of the molar flowrate of CO2, 0.9 kmol d -1 ≤ 𝑛̇C O 2 ,in ≤ 1.1 kmol d -1 , at the reactor inlet. The latter ranges from slightly below the methane production target of 0.91 kmol d -1 up to potentially exceeding the production target by 20%. Note that for SPO the overall inlet stream is identical to the reactor inlet stream.