Kinetic modeling of a combined tar removal and methanation reactor for biogenous synthesis gas at medium temperature conditions

Combined tar steam reforming and methanation at relative low temperatures are an interesting gas cleaning option for decentralized, small-scale allothermal gasification plants. In the course of the work, a thermodynamic model for the tar removal reactor is developed, applying mass and energy balances, reaction kinetics and equilibrium equations. To describe the chemical reactions accurately, kinetic data, for the gas reactions and the steam reforming of tar, considered as two lumps (heterocyclic and polycyclic aromatics), is implemented into the model. The kinetic coefficients are obtained by regressing experimental data considering literature values. Since catalyst deactivation is a major obstacle especially at low temperature conditions, catalyst deactivation is implemented into the model by using the specific-catalyst-consumption, an empirically determined parameter, avoiding the data requirements of a kinetic model. The performance of the reactor model is evaluated and compared to experimental data, showing good agreement with the measured values.