Modeling of a Methanol Synthesis Reactor for Storage of Renewable Energy and Conversion of CO2 - Comparison of Two Kinetic Models

The storage of renewable energy over a long time period, via methanol synthesis, will become very important to reach a greenhouse gas-free energy supply. A steady-state methanol synthesis flowsheet, containing a 2D pseudo-homogeneous reactor, flash, and recycle, is modeled in MATLAB. With the kinetic models of Graaf and Bussche & Froment, two frequently used kinetic models for conventional methanol synthesis are compared and evaluated for applicability regarding methanol synthesis from CO2/H-2. The results are presented for different cases of synthesis gas compositions. Both kinetic models produce similar results when the system is limited by thermodynamic equilibrium. However, differences in reaction rates are observable from the reactor axial molar component profiles of the reaction products.