Modeling, technologic analysis and simulation tool development of a solar-based methanol synthesis process

Abstract

As global methanol demand is rising and with it the CO2 emissions due to its production, the need for green alternatives is growing faster. To address this environmental challenge, the German Aerospace Center (DLR) is developing a Python-based yield calculation software for solar plants to investigate pathways for efficient production of electricity or process heat. This work adds multiple components to the existing library of this yield calculator to feature a complete methanol synthesis process from CO2. By integrating an alkaline electrolyzer, a fixed-bed reactor with gas recycling, and a distillation unit, the implemented components address both the nonlinear efficiency and the complex dynamics of startup processes. These components and their aggregation into a synthesis plant were validated with results from recent literature. The components were analyzed on a technological level regarding their behaviour during startup procedures and load changes to identify potential bottlenecks in production. However, without an economic analysis, no single component stood out as the most critical regarding the startup of the system. With the employed control strategy, the methanol reactor takes longer to adapt too load changes than the other two components due to long residence times of the synthesis gases, while different control strategies could prevent or reduce this divergence.