Fixed Bed Methanation Research Articles

Systematic Determination of Optimal Design-Points of Fully Integrated Power-to-SNG Process Chains Via Detailed Simulation of SOEC Stacks

The target of carbon neutrality by 2050 set in the 2015 Paris agreement requires ambitious investments in renewable energy plants. Most potential lies in solar and wind energy, though their intermittent nature needs to be compensated by means of large-scale energy storage technologies. Power-to-SNG (Synthetic Natural Gas) enables the production of the versatile energy carrier CH4 through the use of electrical energy, allowing long-term storage of energy in chemical form. SNG produced using captured CO2 and green hydrogen is carbon-neutral and could therefore help to reduce the greenhouse gas emissions of the transportation and chemical industry [1].In a Power-to-SNG plant comprising a CO2 capture unit, an electrolyzer and methanation reactors, electrical power is the largest contributor to the levelized cost of the produced SNG [2]. This makes the optimization of the system efficiency a critical step towards achieving commercial viability. Since the water splitting reaction is the largest energy sink in the cascade of conversion steps, the use of Solid Oxide Electrolysis Cells (SOEC) is promising because their energy requirement can be partially covered by high temperature heat provided by the methanation reactors. When optimizing the performance of the plant, the operating conditions of the electrolyzer must therefore be considered in conjunction with other parameters contributing to the thermal balance of the plant, which calls for dedicated system modeling approaches.In this work, multiple Power-to-SNG process chains with integrated SOEC module are developed by means of detailed, yet highly customizable plant and component models. Optimal design points of each plant configuration are determined and comparatively assessed. The different process chains are generated by varying CO2 sources and methanation technologies, whilst processes are resolved down to the individual pumps, heat exchangers, cleaning and conditioning steps. Good comparability between configurations and operating conditions of the plant is guaranteed through ideal thermal integration using the pinch method [3]. The SOEC module is simulated based on high-accuracy, multivariate performance maps obtained from a multi-physics 3D stack simulation tool [4,5] computed on a high-performance cluster. For the simulations, two types of SOEC technologies are considered: Ni-GDC/3YSZ/LSCF-electrolyte supported cells and Ni-YSZ/8YSZ/LSC cathode-supported cells.The plant configurations are optimized independently with a simplex algorithm and thereby, the results of investigations focusing on standalone SOEC stacks or using low level-of-detail stack models in system simulations are ascertained. Results demonstrate the importance of balance-of-plant trade-offs in order to achieve best possible efficiencies. For example, in cases with direct air capture (DAC) of CO2, best results are obtained with endothermal operation of the stack and elevated air flow through the anode. Thus, using electrolyte supported cells, power-to-SNG efficiencies (based on HHV) of 67% (fixed-bed methanation) to 69% (fluidized-bed methanation) can be reached.

Systematic Determination of Optimal Design-Points of Fully Integrated Power-to-SNG Process Chains Via Detailed Simulation of SOEC Stacks

The denomination Power-to-SNG covers technologies for the production of synthetic natural gas (SNG) through methanation of electrolytic hydrogen and captured carbon, enabling long-term storage of electrical energy from intermittent renewable sources. A methodology leveraging the pinch method for the optimization of the operating conditions of power-to-SNG plants is presented and applied to a system layout comprising a series of fixed-bed methanation reactors, a biomass gasification process and solid oxide electrolysis cell (SOEC) stacks, which recover the heat produced by the exothermic methanation process. For the system optimization, a rapid SOEC stack model is built from an underlying detailed multi-physics 3D model whilst maintaining its accuracy. Simulations reveal a maximum system HHV efficiency of 85.2% while identifying optimal operating conditions for all plant components. Moreover, the necessity of integrated system optimization strategies is showcased, as the predicted ideal conditions in the system strongly differ from the optimal conditions of the isolated components.

High oxygen and SNG injection in blast furnace ironmaking with Power to Gas integration and CO2 recycling

In the last years, reduction of CO2 emissions from the steel industry has been of great importance. Carbon capture, oxygen blast furnaces and top gas recycling technologies, among others, have been deeply studied as low carbon solutions. In this paper, a novel integration of carbon capture and power to gas technologies in the steelmaking industry is presented. Green hydrogen via proton exchange membrane (PEM) electrolysis and CO2 via methyldiethanolamine (MDEA) scrubbing from the blast furnace gas (BFG) are used to produce synthetic natural gas in an isothermal fixed bed methanation plant. The latter gas is injected into the blast furnace, closing a carbon loop and reducing coal consumption. The oxygen by-produced in the electrolyser covers the entire oxygen demand of the steelmaking plant and avoids the need for an air separation unit (ASU). The novelty of this work relies on the variation of the oxygen enrichment and its temperature in the hot blast, and how it influences the power to gas integration concept. This power to gas integration is compared with a conventional BF-BOF plant from a technical, economic, energy and environmental point of view. Both plant process configurations were implemented in Aspen Plus simulations, assessing the fossil fuel demand, energy penalty, cost and CO2 emissions. Emission reduction up to 34% can be achieved with power to gas integration, with an energy penalty of 17 MJ/tHM and a cost of 352 €/tCO2.

Optimal operation policies for load changes of fixed‐bed methanation reactors

Chemie Ingenieur TechnikVolume 94, Issue 9 p. 1218-1218 Vortrag Optimal operation policies for load changes of fixed-bed methanation reactors M. Langer, M. LangerSearch for more papers by this authorH. Freund, H. FreundSearch for more papers by this author M. Langer, M. LangerSearch for more papers by this authorH. Freund, H. FreundSearch for more papers by this author First published: 25 August 2022 https://doi.org/10.1002/cite.202255392AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume94, Issue9Special Issue: (Bio)Process Engineering – a Key to Sustainable Development: ProcessNet and DECHEMA-BioTechNet Jahrestagungen 2022 together with 13th ESBES SymposiumSeptember 2022Pages 1218-1218 RelatedInformation

Methanation Pilot Plant with a Slurry Bubble Column Reactor: Setup and First Experimental Results

As a part of various research projects, a methanation pilot plant with a slurry bubble column reactor (SBCR) was commissioned and operated. The plant has a nominal load of a 100 kW methane output (lower calorific value) with a reactor diameter of 260 mm and a reactor length of 2500 mm. First experimental data on the steady-state and dynamic operation of catalytic CO2 methanation are presented. Steady-state results from laboratory-scale studies (<1 kW methane output) published previously were confirmed qualitatively at the pilot plant eliminating wall effects unavoidable in small-scale reactors. As predicted, high H2/CO2 ratios increase CO2 conversion, but excess H2 apparently promotes decomposition of the liquid phase (dibenzyltoluene) used in the bubble column reactor. Additionally, due to the increased reactor dimensions compared to laboratory equipment, it was now possible to observe a thermal response of the SBCR under conditions of rapid gas load changes characteristic of envisaged power-to-gas applications with volatile renewable electricity. As the predicted robustness of the SBCR-concept toward a dynamic operation with fast load changes was demonstrated successfully, it offers an attractive alternative to the established fixed-bed methanation technologies with their inherent limitations on dynamic operability.

2D heterogeneous model of a polytropic methanation reactor

The paper presents a heterogeneous 2D model of a polytropic fixed bed methanation reactor for Co-SOEC syngas. The reactor with 80 mm inner diameter is operated without active cooling. Lab-scale experiments were used for model validation under variation of gas hourly space velocity (GHSV) (2000 h-1, 4000 h-1, 6000 h-1 and 8000 h-1) and pressure (1 bar, 2 bar, 4 bar, 6 bar, 8 bar, 10 bar). The conversion of Co-SOEC syngas containing a mixture of H2, CO and CO2 was calculated based on a two-step methanation kinetic model. Effective methanation kinetics was implemented based on a novel approximation of two different reaction efficiency approaches. The catalytic efficiency approximation combines conventional power law related and a Langmuir-Hinshelwood type reaction efficiency correlation by Roberts and Satterfield. It was found that mass transfer limitation is substantial for highly temperature sensitive polytropic methanation reactor modelling. Despite high exothermic behaviour without active cooling, a stable model set-up was managed entirely without parameter fitting to experimental data for a naturally cooled methanation reactor with highly reactive and undiluted syngas feed. The modelled results of Co-SOEC syngas methanation agree well with the experiments over a wide variety of pressure and GHSV. The interaction and limiting factors of mass diffusion, reaction heat removal, kinetics and thermodynamics can be thoroughly analysed based on the established model, which is a key step for developing highly efficient methanation reactor systems in industrial scale.

Hydrogenation of CO/CO2 mixtures under unsteady-state conditions: Effect of the carbon oxides on the dynamic methanation process

The Power-to-Gas (PtG) process offers the opportunity to store fluctuating renewable energy in form of chemical energy by hydrogenating carbon oxides into methane. In addition, potential carbon point sources often consist of CO/CO2 (COx) mixtures. Hence, reactor design requires kinetic models valid for unsteady-state operation and a broad spectrum of feed gas compositions. In order to provide the required experimental data basis for derivation of kinetic expressions valid under transient conditions, the dynamic response of a continuously operated fixed-bed methanation reactor is studied by applying periodic step-changes in the feed composition. The obtained results are evaluated based on a simple reactor model, providing the molar flow rate exchanged between the gas bulk and the solid surface for CO, CO2, CH4, and H2O. The results further reveal that the transient kinetic processes at the catalyst surface strongly affect the reactor response under reaction conditions of technical relevance.

Heat Recovery from a PtSNG Plant Coupled with Wind Energy

Power to substitute natural gas (PtSNG) is a promising technology to store intermittent renewable electricity as synthetic fuel. Power surplus on the electric grid is converted to hydrogen via water electrolysis and then to SNG via CO2 methanation. The SNG produced can be directly injected into the natural gas infrastructure for long-term and large-scale energy storage. Because of the fluctuating behaviour of the input energy source, the overall annual plant efficiency and SNG production are affected by the plant operation time and the standby strategy chosen. The re-use of internal (waste) heat for satisfying the energy requirements during critical moments can be crucial to achieving high annual efficiencies. In this study, the heat recovery from a PtSNG plant coupled with wind energy, based on proton exchange membrane electrolysis, adiabatic fixed bed methanation and membrane technology for SNG upgrading, is investigated. The proposed thermal recovery strategy involves the waste heat available from the methanation unit during the operation hours being accumulated by means of a two-tanks diathermic oil circuit. The stored heat is used to compensate for the heat losses of methanation reactors, during the hot-standby state. Two options to maintain the reactors at operating temperature have been assessed. The first requires that the diathermic oil transfers heat to a hydrogen stream, which is used to flush the reactors in order to guarantee the hot-standby conditions. The second option entails that the stored heat being recovered for electricity production through an Organic Rankine Cycle. The electricity produced is used to compensate the reactors heat losses by using electrical trace heating during the hot-standby hours, as well as to supply energy to ancillary equipment. The aim of the paper is to evaluate the technical feasibility of the proposed heat recovery strategies and how they impact on the annual plant performances. The results showed that the annual efficiencies on an LHV basis were found to be 44.0% and 44.3% for the thermal storage and electrical storage configurations, respectively.

Fixed-bed reactors for exothermic reactions: A qualitative relation between start-up time and traveling waves velocity

An experimental investigation of the reaction front movements upon reacting gas injection in a pre-heated non-adiabatic fixed-bed methanation reactor is conducted. The relocation starts with a backward movement of the front, whose maximal velocity turns out to be a linear function of the temperature setpoint. The front then moves forward in response to the fact that the injected cold gas cools down the bed in the upstream zone. The front stabilizes asymptotically in the downstream (upstream, resp.) zone of the reactor after a characteristic time that is an increasing (decreasing, resp.) function of the temperature setpoint, if the setpoint is below (above, resp.) a certain threshold. This behavior is interpreted in terms of reaction wave velocity.

Catalytic reactors for highly exothermic reactions: Steady-state stability enhancement by magnetic induction

The thermal management of catalytic reactors dedicated to highly exothermic reactions is often challenging, due to the existence of a positive thermal feedback. Up to now, many design and control options have been used to operate such reactors safely and efficiently. The present study examines the theoretical benefit of resorting to an alternative stabilization strategy based on the use of induction-heated pellets. Under given inductive conditions, the thermal power released by these pellets is a decreasing function of their temperature (negative thermal feedback). Wall-cooled fixed-bed methanation reactors containing mixed catalytic and induction-sensitive pellets are simulated numerically. The steady-state behavior of reactors enhanced by induction is compared to the behavior of conventional reactors. It is shown that the parametric sensitivity of induction reactors is lower than that of a conventional reactor achieving the same conversion. Induction reactors also demonstrate an ability to reach a higher chemical yield than a conventional reactor, before entering the runaway region. The impact of the operation conditions (inductive field, coolant temperature) and of the induction-sensitive pellets properties (absorption rate as a function of temperature) on the stabilization is analyzed.

Optimal catalyst particle design for flexible fixed-bed CO2 methanation reactors

Power-to-Methane is a concept for energy storage harvested from renewable sources, for instance solar and wind power. A flexible operation of catalytic fixed-bed methanation reactors, according to the availability of energy, eliminates the need to store intermediate reactants in large buffer units. This requires reliable heat management, as the heat generation of the methanation reaction is a challenge even at steady-state conditions. For this purpose, many studies have been conducted on the reactor scale, but knowledge on how the catalyst particle design can influence reactor behavior is rather limited. Therefore, a heterogeneous reactor model is used in this study to investigate the influence of particle activity, permeability and heat conductivity on reactor performance. Subsequently, a nonlinear program is formulated and solved to find the optimal particle design depending on these three properties and their radial distribution in the catalyst particles. The designs include spherical particles with uniform properties (Case1), particles with two uniform zones of different properties (Case2) and particles with radially variable properties (Case3). Optimization, subsequent sensitivity analyses and dynamic simulations reveal that reactors filled with particles of Case2 should exhibit a particle core with high activity, which is surrounded by an inert, low-permeability shell (so-called ‘egg-yolk’ particles). In this way, the reactor shows a reduced parametric sensitivity and a high methane yield at the same time. In comparison to reactors filled with particles of Case1, they also exhibit a favorable behavior for dynamic and flexible reactor operation. The benefit of further particle zones to increase reactor performance appears insignificant, as shown by the results of Case3.

Dynamic operation of fixed-bed methanation reactors: Yield control by catalyst dilution profile and magnetic induction

Dynamic operation of fixed-bed methanation reactors has been subject to increasing research efforts over the past years, as a consequence of its potential interest for the energy transition (power-to-gas). Due to the reaction exothermicity, the thermal management of a reactor is particularly difficult. In the present work, a model and a software are developed to simulate the behavior of a reactor whose reaction medium contains a mixture of catalytic pellets and induction-sensitive pellets. The study shows that a reactor made-up of two reaction zones of different catalytic fractions can produce a gas of identical steady-state compositions for two different flow rates. A steep shift from the low to the high inflow rate generates a transient drop in the methane yield. Magnetic induction rapidly heats up an appropriate portion of the reaction medium, so that the yield remains nearly constant during both transient and steady state after a flow rate shift. This study constitutes a first step towards the final aim of using induction and catalyst dilution profile to stabilize the yield for any flow rate variation in a given range.

Dynamic Carbon Dioxide Methanation in a Wall-Cooled Fixed Bed Reactor: Comparative Evaluation of Reactor Models

A comprehensive model comparison is presented for the description of the steady state and dynamic behavior of a wall-cooled fixed bed methanation reactor. First, the maximal conversion predicted by different steady state models is compared and evaluated. Second, the dynamic reactor behavior is investigated based on positive and negative step changes of the inlet flow rate. The examined model complexity ranges from a simple one-dimensional pseudohomogeneous reactor model to a two-dimensional heterogeneous model. The results show that similar maximal conversions are predicted by each model, but large discrepancies appear for the prediction of the dynamic reactor behavior. Our data clarify the impact of the considered heat and mass transfer resistances on the model prediction and allow us to give specific recommendations for further steady state and dynamic modeling works.

Kinetics and Reactor Design Aspects of Selective Methanation of CO over a Ru/γ-Al2O3 Catalyst in CO2/H2 Rich Gases

Polymer electrolyte membrane fuel cells (PEMFCs) for household applications utilize H2 produced from natural gas via steam reforming followed by a water gas shift (WGS) unit. The H2-rich gas contains CO2 and small amounts of CO, which is a poison for PEMFCs. Today, CO is mostly converted by addition of O2 and preferential oxidation, but H2 is then also partly oxidized. An alternative is selective CO methanation, studied in this work. CO2 methanation is then a highly unwanted reaction, consuming additional H2. The kinetics of CO methanation in CO2/H2 rich gases were studied with a home-made Ru catalyst in a fixed bed reactor at 1 bar and 160–240 °C. Both CO and CO2 methanation can be well described by a Langmuir Hinshelwood approach. The rate of CO2 methanation is slow compared to CO. CO2 is directly converted to methane, i.e., the indirect route via reverse water gas shift (WGS) and subsequent CO methanation could be excluded by the experimental data and in combination with kinetic considerations. Pore diffusion may affect the CO conversion (&gt;200 °C). The kinetic equations were applied to model an adiabatic fixed bed methanation reactor of a fuel cell appliance.

Intermittent Operation of Fixed-Bed Methanation Reactors: A Simple Relation Between Start-Up Time and Idle State Duration

Power to gas is a way to convert surplus electricity available on the grid (that might come from renewable sources like solar or wind) and store it as methane. It is also a way to valorize carbon dioxide and reduce CO2 emissions into the atmosphere. At the heart of the process, the methanation reaction has to achieve high-performance conversion in a completely dynamic mode of operation. This mode of operation—linked to the fluctuations of available power on the grid, and the possible thermal runaway of the reactor due to the exothermic nature of the methanation reaction—means that special care is needed in the design of the reactor as well as its control. The reactor, which might be catalytic fixed-bed, should also restart quickly after an idle period. Start-up requires the reactor temperature to be sufficiently high to ignite the reaction. In this paper, the intermittent operation of a fixed-bed methanation reactor is studied. A mathematical model is developed in order to simulate successive gas shutdowns and reinjections. It is examined as well if the reactor is able to restart spontaneously (i.e. with no external heating, but utilizing thermal inertia and the exothermicity of the reaction), when reactants are reinjected after an idle phase. A relation is found between the respective durations of spontaneous restart and idle phase, which can be used to evaluate whether using an external heat source is preferable to relying on spontaneous restart.

Direct catalytic methanation of biogas – Part II: Techno-economic process assessment and feasibility reflections

Six different processes for the direct methanation of biogas for biomethane production were evaluated regarding their economically optimised operating conditions, their absolute costs and profitability. Detailed process simulations turned out to be important to obtain a solid process design so that a realistic cost estimate is possible. This is necessary since the stated costs in literature vary by a factor of 10 due to the shortage of simulation details. In addition, cost data for the methanation from recent literature are often under-estimated due to the lack of a required second upgrading step (post-upgrading) to reach the demanded gas grid specifications and of additional process equipment. A fixed bed methanation reactor is two times more expensive than a bubbling fluidised bed reactor but due to the dominant share of costs of the electrolysis, costs differences between the whole processes of 5% are less pronounced. It turned out that a gas separation membrane and a second fixed bed, as a post-upgrading step, are equally expensive. However, a gas separation membrane seems to be technically more robust. Biomethane production costs of 10.2 Ct€/kWhtotal for processes containing a fluidised bed and of 10.7 Ct€/kWhtotal for processes containing a main fixed bed are obtained. As a consequence, the corresponding processes are profitable until an electricity price of 6.0 Ct€/kWhel and 5.3 Ct€/kWhel without considering the extra revenues from process heat and oxygen. Furthermore, the profitability of the processes increases with the methane content in the biogas. Considering extra revenues and a concentration increase of 10% for methane in the biogas, the maximum electricity price for a profitable process increases by 3 Ct€/kWhel.

Optimization of fixed-bed methanation reactors: Safe and efficient operation under transient and steady-state conditions

Designing and optimizing packed-bed methanation reactors for power-to-gas leads to conflicting issues. Because of the high exothermicity of the reaction, it might be inefficient (low Gas Hourly Space Velocity), or unsafe (runaway, thermal degradation). Dynamically operating reactors are thus particularly difficult to design. In this paper, the behavior of a reactor with multiple catalyst-dilution zones is studied numerically. Simulations of a dynamic sequence (reactor startup) are carried out. The effect of catalyst dilution profile on steady state and transient efficiency is analyzed. We introduce a method to maximize GHSV, while guarantying safe operation during both transient and steady state operation. A proper catalyst dilution profile can increase the steady state efficiency and stability of the reactor. However, the results of the present study show that this dilution profile can have a negative impact on transient efficiency and stability.

Optimal design of solid-oxide electrolyzer based power-to-methane systems: A comprehensive comparison between steam electrolysis and co-electrolysis

Power-to-methane technologies have been regarded as a promising alternative to offer small- or large-scale, long-timescale (daily/weekly/seasonal) energy storage as well as the opportunity of utilizing CO2. The performance of the core component, the electrolyzer, largely determines how well a power-to-methane system can perform, making high-temperature solid-oxide electrolysis attractive because of its inherent high electrical efficiency. More importantly, solid-oxide electrolysis uniquely allows co-electrolysis of steam and CO2 for producing syngas, the composition of which can be readily, flexibly adjusted to synthesize different hydrocarbon fuels. In this paper, for both steam- and co-electrolysis, we comprehensively and comparatively investigate several critical design issues of a solid-oxide electrolyzer based power-to-methane system with fixed-bed methanation reactor and membrane-based methane upgrading: (1) system-level heat integration, (2) the impacts of operating variables (e.g., operating voltage, reactant utilization, anode/cathode feed ratio, and operating pressure of the methanation reactor and membrane) on system performances, (3) the competitiveness of the electrolyzer operation with pure oxygen production, and (4) the possibility of avoiding electrical heating, which is necessary for thermoneutral operation to heat up the electrolyzer feeds to the required temperature. To achieve this target, a multi-objective optimization platform with integrated heat cascade calculation is employed with experimentally-calibrated component models. The results show that, for both steam- and co-electrolysis, there is a trade-off between system efficiency and methane yield: pursuing a higher efficiency generally reduces the methane yield, which is a consequence of electrochemistry, stack cooling and system-level heat integration. Instead of sweep air, pure oxygen production is preferred only at small current density, which delivers the highest system efficiency but the lowest methane yield. When the electrolyzer operates exothermically, methane production and the total power consumption can vary in much wider ranges than those with the electrolyzer operating under thermoneutral mode, which leads to potential enhancement of operation flexibility and reliability. The co-electrolysis coupling with strongly-exothermic syngas methanation, in general, offers better heat-integration opportunity with sweep air, but less with pure oxygen production. In addition, several design heuristics, e.g., the operating pressure of the electrolyzer and methanation reactor, are concluded to potentially guide practical applications.

Influence of hydrocarbons and thiophene on catalytic fixed bed methanation

The economics of decentralized methanation units require a reduced complexity of the gas cleanup of gasification-derived syngas resulting in higher concentrations of organic sulfur compounds, e.g. thiophene. The influence of thiophene as single compound as well as in combination with higher hydrocarbons on catalytic fixed bed methanation has been experimentally examined in a series of bench-scale tests with a commercial Ni catalyst. The change of activity of the catalytic fixed bed was studied by methanation under well-defined reference settings. For intermediate catalyst treatment the impurities thiophene, as major sulfur species unremoved by acid gas scrubbing, as well as ethene and naphthalene as major hydrocarbon species in syngas, have been chosen. In all experiments thiophene addition showed a slow but steadily-ongoing deactivation of the catalytic fixed bed with catalyst consumption varying from 0.6 to 1.7 gcatalyst/mmolC4H4S. Addition of 1.0vol.% ethene to the feedgas resulted in significant increase of the pressure drop over the fixed bed, whereas simultaneous addition of thiophene and ethene, as well as single or combined addition of naphthalene, did not cause any increase of the pressure drop. The results were compared to the sulfur passivated steam reforming but in case of methanation no similar mechanism is likely to exist.

Simulation-Based Evaluation of a Two-Stage Small-Scale Methanation Unit for Decentralized Applications

The present work aims for a simulation-based evaluation of a two-stage methanation unit for the production of substitute natural gas (SNG) in decentralized small-scale applications with low complexity. Equilibrium calculations reveal a remarkable impact of CO2 removal efficiency on final SNG composition with an optimum removal efficiency of 85% for the examined synthesis gas. The first methanation stage consists of a polytropic fixed-bed methanation reactor and is implemented as a one-dimensional pseudohomogeneous model in Aspen PlusTM with reaction kinetics from literature. The comparison of three different kinetic models reveals that reverse reaction of CO methanation has to be considered in the kinetic rate equations for appropriate modeling within a dynamic temperature range above 400 °C in case of polytropic reactors. The first methanation stage is examined with one kinetic model in terms of reactor geometry, varying GHSV and influence of the feed gas composition to determine limits in upscaling and avoidance of too high temperatures. A significant decrease of the reactor diameter favors the heat removal in case of polytropic reactor concept, whereas a higher GHSV causes higher outlet temperatures. The results show that an effective operation of the proposed methanation concept is limited by an appropriate heat removal.