The conversion of steel mill off-gases to base chemicals is a promising perspective to improve the financial return of steelmaking in Europe and fight CO2 emissions. In the Carbon2Chem (R) joint research project, mathematical models are developed to simulate operation scenarios of cross-industrial networks and chemical plants embedded in a steel mill environment. Methodically, the modeling follows a multilevel approach combining models of different depth and origin in a common simulation framework. Here, the synthesis of methanol is simulated and analyzed for different gas conditioning scenarios.