In fig. , the step responses in the limit cycle of the reactant CO and the products CH4, C2, C3+ and H2O during the build-up phase are shown. Note that the results are normalized to the values at the end of the build-up phase for each individual species. As seen here, the carbonaceous products exhibit a strong overshoot over the steady-state formation rate as represented from the RTD behavior, shown in the black line (see b). CH4 exhibits the highest overshoot with around 1.55 times the steady-state formation rate in the maximum, followed by C2 and C3+ with 1.23 and 1.17 times the steady-state formation rate, respectively. CH4 increases the fastest, after which C2 and the C3+ start to increase subsequently and also reach the maximum slightly later. C2 and C3+ show a second maximum (see c) after around 1 min of time on stream (TOS), after which all species then decrease slowly to the steadystate value, while the decrease is slower, the higher the carbon number is, as seen in figure ).