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For the design and optimization of methfanation processes detailed modeling and simulation work is advisable. However, only a few kinetics published in literature rely on wide temperature and pressure ranges, which are prevalent at modern methanation applications with dynamic operation. Especially the simulation‐based design of methanation processes with commercial catalysts is difficult due to legal restrictions regarding the publication of kinetic data of those catalysts. In this work, rate equations for the dynamic modeling and simulation of methanation processes operating with commercial Ni/Al2O3 catalysts are selected, adapted, and tested in a dynamic reactor model. The results suggest that the catalyst's nickel content is an indicator for the choice of a rate equation. Testing of the equations in a reactor model meets published data for CO and CO2 methanation and own measurements.

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The power‐to‐gas (PtG) process, enabling the long‐term indirect storage of electrical energy, includes the water electrolysis for hydrogen production and the subsequent hydrogenation of carbon dioxide in a methanation reactor. The dynamic operation of methanation reactors is favored to limit upstream storage capacities, but not fully understood thus far. Therefore, this contribution investigates the dynamic operation of a fixed‐bed recycle reactor during flow rate ramps with a variation of the ramp time. Load ramps of the volumetric flow rate lead to global maxima during the transition; for the methane content if the flow rate is decreased, and for the gas temperature if the flow rate is increased. Furthermore, the adaptation of the product recirculation during flow rate ramps is discussed at the end. The recycle ratio turns out to provide an additional degree of freedom for stabilizing the reactor behavior under fluctuating feed conditions.

The production of synthetic natural gas (SNG) from renewable sources in cases requires a dynamic and intermitted operation of the methanation reactors. This may lead to catalyst damage. Therefore, the present work is aiming at identifying restrictions and optimization approaches of the start‐and‐stop operation of fixed‐bed methanation reactors. 2D modeling and simulation work is conducted and the warm‐start behavior of a fixed‐bed reactor after one to four hours operation intermittence is analyzed. The result reveals the possibility for an operation interruption of up to four hours without high adaptation effort to restart the reactor. After approximately four hours, the catalyst bed at the inlet part of the reactor reaches a temperature that provokes problems for a subsequent warm start.

Methanation of Synthetic Gas -Fundamentals and Process DevelopmentRegarding the provision of energy, natural gas makes a significant contribution. To reduce the dependency on natural gas imports and therewith price fluctuations on the one hand and to use the existing natural gas infrastructure on the other hand, natural gas can be substituted to some extent by synthetic natural gas (SNG). SNG can be produced either from coal or -with special focus on the reduction of anthropogenic greenhouse gas emissions -from biomass. Considering the thermochemical conversion pathway from the fuel to SNG the process step methanation has high influence on the process efficiency as well as on up-and downstream process steps. Therefore, in this paper the basics of methanation and main process developments are described.

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Eine Möglichkeit für die bedarfsgerechte Nutzung von Biomasse ist deren thermochemische Vergasung. Das erzeugte Gas kann entsprechend den Marktgegebenheiten direkt zur Stromerzeugung genutzt oder Methanisierungsreaktoren zugeführt und anschließend im Erdgasnetz gespeichert werden. Eine Voraussetzung dafür sind lastflexible Methanisierungsreaktoren. Daher wird hier der lastflexible Betrieb der Methanisierung anhand eines dynamischen Simulationsmodells untersucht und bewertet. Die Untersuchung zeigt, dass es bei Laststeigerungen ohne geeignete Gegenmaßnahmen zu einer Überhitzung der Katalysatoren kommen kann.Combined production of power and synthetic natural gas from solid biomass is one option for a demand-oriented use of bioenergy. Respective plants consist of two main process steps: biomass gasification and subsequent gas usage (methanation or power production). However, a flexible plant operation is related to challenges regarding the methanation. Therefore, the operational flexibility of fixed-bed methanation is investigated with the help of a dynamic simulation model. The analysis of gas feed ramps shows a catalyst temperature rise with increased gas throughputs in comparison to the nominal load.