Model‐based Optimal Sabatier Reactor Design for Power‐to‐Gas Applications

Abstract

The existing infrastructure for natural gas storage and transport made the Sabatier process an attractive step within the power‐to‐gas process chain for intermittent renewable energy storage. A model‐based optimal design for the methanation of carbon dioxide with hydrogen to methane under process‐wide constraints is presented. After inclusion of the downstream units into the analysis, the product methane fulfils the specifications for the natural gas grid. The optimization goal was to maximize the space–time yield by applying the systematic flux‐oriented elementary process function methodology. The optimum temperature and concentration profiles along the reaction coordinate were first determined, after which they were approximated using two reaction configurations: 1) a hydrophilic membrane reactor and 2) a cascade of polytropic reactors with interstage condensation. The results show that an optimized cascade of three polytropic fixed bed reactors (e.g., optimum temperature profile) and two intermediate condensation steps is the best technical approximation for maximizing the space–time yield.

Operation range extensionviahot-spot control for catalytic CO2methanation reactors

“…Just to mention a few, Kiewidt and Thöming 24 proposed a modelbased Semenov number optimization approach to compute optimal axial temperature profiles while maintaining the catalyst temperature limitation. Further optimization studies in this context, with special focus on steady operation of an entire methanation plant model, were provided by El Sibai et al 25 In accordance with our previous work, this study aims for more fundamental explanations and a better understanding of our model-based optimization results with respect to a broader operation range, as well as technical relevance among other concepts. One major outcome is the identification of dynamically stabilized operation regimes of industrial-scale reactors, which exist due to the appearance of multiple steady-states.…”

CO2 Methanation in Microstructured Reactors – Catalyst Development and Process Design

“…determines the degree of conversion which can be achieved in a single (adiabatic) reactor stage. Detailed analysis of the process reveals that two or more reactor stages even with integrated cooling capabilities or subsequent purification steps seem to be inevitable to achieve high conversion and superior gas quality for the injection into the gas grid. However, Schollenberger et al proposed a concept of two honeycomb reactor stages with external oil cooling to reach 99 % CO 2 conversion, while Matthischke et al considered recycling the product of a fixed‐bed reactor to improve the heat management and transient performance.…”

Exergetic assessment of CO2 methanation processes for the chemical storage of renewable energies

“…Because of this, we choose adsorption as the separation process. [23] has demonstrated recently that in a reactor cascade with an equilibrium limited second reactor the product gas fulfills the gas grid specifications in terms of H 2 and CO 2 concentration after drying. Configuration A is closely similar to the pilot unit operating since 2013 in Germany [24, p. 821] and is therefore seen as a reference in this exergy analysis.…”