Figure 3 shows the influence of the

Figure 3 shows the influence of the CO2 concentration on the reaction rate. The degree of CO2 conversion was kept below 10 % to realize differential conditions (rCO2 = − dcCO2/dτ ≈ cCO2,in XCO2/τ). The volume rate was 16 to 22 l h−1 (STP). The agreement of the experimental data and the rates calculated by Equation (6) is satisfactory. The rate of CO2 methanation increases with increasing CO2 concentration to a maximum and then decreases for high CO2 concentrations (>5 mol·m−3 = 18 vol-%),asshowninFigure3bythecalculationfor234◦CandhighvaluesofcCO2. Theonlyproduct found for CO2 conversion is methane, which is a first indication of a negligible activity of the catalyst for the RWGS, Equation (3), an aspect discussed below in more detail