The work proposes a simplified kinetic model for Fischer–Tropsch synthesis from CO2, incorporating the reverse water-gas shift reaction and generalized steps for the formation of methane, C2–C4 hydrocarbons, and the C5⁺ fraction. The kinetic parameters of the model were determined based on experimental data in the temperature range of 260–320°C and pressures of 20–30 atm by solving the inverse chemical kinetics problem using a combination of a genetic algorithm and the Levenberg–Marquardt method. It is shown that the reverse water-gas shift reaction under the studied conditions does not reach thermodynamic equilibrium and limits the overall conversion of CO2. The analysis of activation energies explains the observed decrease in selectivity towards heavy hydrocarbons in favor of lighter fractions with increasing temperature. Comparing the calculated data (for pure CO2) with experimental results obtained when feeding ammonia made it possible to estimate the contribution of amination reactions. It was revealed that in the presence of ammonia, a reduction in the selectivity of methane formation as the main undesirable reaction product is achieved.
Starozhitskaya et al. (Thu,) studied this question.