Conception et simulation du fonctionnement d’une unité de stockage/déstockage d’électricité renouvelable sur méthane de synthèse au moyen d’un co-électrolyseur à haute température réversible : Approches stationnaire et dynamique

The objective of this thesis is to design, evaluate the energetic performance and study the transient behavior during heating and startup operations of a reversible process Power To Gas process which is a solution for the integration of renewable electricity in the energy mix. Steady state models are first established in Aspen plus. Assessment of energetic performance shows that 66.7% of the electrical energy is stored as a Synthetic Natural Gas and the losses are caused mainly by the converting steps: the AC/DC, co-electrolysis and methanation conversions. Electricity production (Gas to Power) is performed by reversing the RSOC in SOFC mode fueled by synthesis gas (CO and H2) produced in a tri-reformer. This process is energetically autonomous and produces untapped heat which causes its 40% low efficiency. A study of the transient response during heat-up and start-up operations is conducted through the development of dynamic models of reversible co- electrolyzer, reactors and heat exchangers by using Matlab and Dymola softwares. The results allow to specify the energetic penalty and to review the architecture of predefined process in steady state. Several strategies have been studied to optimize the time and the energy consumption. It turned out that the RSOC is the slowest component (60% of total time) with the most energetic consumption (71% of total energy) because of the amount of gas used in heat-up operation and the significant time that must be respected in order to ensure an increase in temperature that prevents the cells deterioration.L'objectif de cette thèse est de concevoir, d'évaluer les performances énergétiques et d'étudier le comportement en régime transitoire pendant les opérations de chauffage et de démarrage d'un procédé réversible Power To Gas qui est une solution pour l'intégration des énergies renouvelables dans le mix énergétique. L'évaluation des performances énergétiques montre que 66,7% de l'énergie électrique entrante est stockée sous forme de substitut du gaz naturel et que les pertes concernent principalement les étapes de conversion en particulier la conversion AC/DC, la co-électrolyse et la méthanation. Le déstockage de l'électricité (Gas To Power) est réalisé en inversant le RSOC en mode SOFC alimenté par le gaz de synthèse (H2 et CO) produit dans un tri-reformeur. Ce procédé est autonome énergétiquement et produit de la chaleur inexploitée qui est à l'origine de sa faible efficacité de 40%. Une étude de la réponse en régime transitoire est conduite en développant des modèles dynamiques du co-électrolyseur réversible, des réacteurs et des échangeurs par le biais de deux logiciels: Matlab et Dymola. Les résultats permettent de préciser la pénalité énergétique et de revoir l'architecture du procédé prédéfinie en régime stationnaire. Plusieurs stratégies ont été étudiées afin d'optimiser le temps de démarrage et l'énergie consommée. Il s'est avéré que le RSOC est le composant qui consomme le plus d'énergie (71% de l'énergie totale) et qui nécessite le plus de temps de démarrage (60% du temps total) à cause de la quantité du gaz utilisée pour le chauffage et du temps important qu'il faut respecter afin d'assurer une augmentation en température progressive qui évite la détérioration des cellules

Production of Synthetic Gasoline and Diesel Fuel from Dry Reforming of Methane

AbstractThe dry reforming of methane produces synthesis gas from carbon dioxide and methane (CH4). Although this concept has many environmental and economic incentives, today it is not implemented in large plants. The purpose of this study is to illustrate the potential of dry reforming of methane for industrial applications by producing synthetic fuel from the combination of dry and steam reforming of methane. The proposed process includes four main units: production of synthesis gas from the dry and the steam reforming of methane, Fischer Tropsch synthesis, waxes hydro-cracking Fischer Tropsch waxes, product upgrading and hydrogen recovery. Simulation model of this process is carried out with Aspen Plus® software (Advanced System for Process Engineering) which allows us to define and analyze the optimum conditions and equipment specifications for each unit. Energy consumption and CO2 balance of this process are also calculated. The main interest of our proposed process is its very favorable carbon balance

Design and simulation of the operation for methane storage system of renewable electricity based on reversible high temperature co-electrolysis : stationary and dynamic approaches

L'objectif de cette thèse est de concevoir, d'évaluer les performances énergétiques et d'étudier le comportement en régime transitoire pendant les opérations de chauffage et de démarrage d'un procédé réversible Power To Gas qui est une solution pour l'intégration des énergies renouvelables dans le mix énergétique. L'évaluation des performances énergétiques montre que 66,7% de l'énergie électrique entrante est stockée sous forme de substitut du gaz naturel et que les pertes concernent principalement les étapes de conversion en particulier la conversion AC/DC, la co-électrolyse et la méthanation. Le déstockage de l'électricité (Gas To Power) est réalisé en inversant le RSOC en mode SOFC alimenté par le gaz de synthèse (H2 et CO) produit dans un tri-reformeur. Ce procédé est autonome énergétiquement et produit de la chaleur inexploitée qui est à l'origine de sa faible efficacité de 40%. Une étude de la réponse en régime transitoire est conduite en développant des modèles dynamiques du co-électrolyseur réversible, des réacteurs et des échangeurs par le biais de deux logiciels: Matlab et Dymola. Les résultats permettent de préciser la pénalité énergétique et de revoir l'architecture du procédé prédéfinie en régime stationnaire. Plusieurs stratégies ont été étudiées afin d'optimiser le temps de démarrage et l'énergie consommée. Il s'est avéré que le RSOC est le composant qui consomme le plus d'énergie (71% de l'énergie totale) et qui nécessite le plus de temps de démarrage (60% du temps total) à cause de la quantité du gaz utilisée pour le chauffage et du temps important qu'il faut respecter afin d'assurer une augmentation en température progressive qui évite la détérioration des cellules.The objective of this thesis is to design, evaluate the energetic performance and study the transient behavior during heating and startup operations of a reversible process Power To Gas process which is a solution for the integration of renewable electricity in the energy mix. Steady state models are first established in Aspen plus. Assessment of energetic performance shows that 66.7% of the electrical energy is stored as a Synthetic Natural Gas and the losses are caused mainly by the converting steps: the AC/DC, co-electrolysis and methanation conversions. Electricity production (Gas to Power) is performed by reversing the RSOC in SOFC mode fueled by synthesis gas (CO and H2) produced in a tri-reformer. This process is energetically autonomous and produces untapped heat which causes its 40% low efficiency. A study of the transient response during heat-up and start-up operations is conducted through the development of dynamic models of reversible co- electrolyzer, reactors and heat exchangers by using Matlab and Dymola softwares. The results allow to specify the energetic penalty and to review the architecture of predefined process in steady state. Several strategies have been studied to optimize the time and the energy consumption. It turned out that the RSOC is the slowest component (60% of total time) with the most energetic consumption (71% of total energy) because of the amount of gas used in heat-up operation and the significant time that must be respected in order to ensure an increase in temperature that prevents the cells deterioration

Modeling and simulation of CO methanation process for renewable electricity storage

International audienceIn this paper, a new approach of converting renewable electricity into methane via syngas (a mixture of CO and H2) and CO methanation is presented. Surplus of electricity is used to electrolyze H2O and CO2 to H2 and CO by using a SOEC (Solid Oxide Electrolysis Cell). Syngas produced is then converted into methane. When high consumption peaks appear, methane is used to produce electricity. The main conversion step in this process is CO methanation. A modeling of catalytic fixed bed methanation reactor and a design of methanation unit composed of multistage adiabatic reactors are carried out using Aspen plus™ software. The model was validated by comparing the simulated results of gas composition (CH4, CO, CO2 and H2) with industrial data. In addition, the effects of recycle ratio on adiabatic reactor stages, outlet temperature, and H2 and CO conversions are carefully investigated. It is found that for storing 10 MW of renewable electricity, methanation unit is composed of three adiabatic reactors with recycle loop and intermediate cooling at 553 K and 1.5 MPa. The methanation unit generates 3778.6 kg/h of steam at 523.2 K and 1 MPa (13.67 MW)

Methanation catalytic reactor

International audienceStoring renewable electricity in a natural gas grid is a new approach for seasonal storage. Using the existing natural gas infrastructure, a chemical energy source (methane) is stored efficiently, distributed and made available for use as required. Thus, the main step in the storage process is CO methanation. Modelling of an isothermal methanation catalytic reactor based on a kinetic scheme was carried out with Aspen plus™ software in a temperature range between 520 and 600 K and a H2/CO molar ratio of 3, in the presence of CO2 and steam. The model was validated by comparing simulation results with experimental ones. The maximum relative error is 10.87%. The effects of temperature, pressure and CO2 addition in feed gas (syngas) on CO conversion and the outlet gas composition were carefully investigated

Dry reforming of methane - Review of feasibility studies

International audienceStarting from carbon dioxide and methane, the dry reforming of methane produces synthesis gas which is a mixture of hydrogen and carbon monoxide. Although this concept has many environmental and economic incentives, unfortunately, there are no commercial processes for dry reforming of methane. In this paper a review of feasibility studies is presented. Firstly, a comparison between the steam reforming and the dry reforming of methane is performed as well as a study of the production of methanol and sulfur-free diesel from the dry reforming of methane. Furthermore, a thermodynamic analysis is carried out by the method of equilibrium constants, for defining the thermodynamic limit and the optimum conditions

Performance assessment of a power-to-gas process based on reversible solid oxide cell

International audienc

CO2 valorization: Production of synthetic gasoline and diesel fuel from dry reforming of methane

International audienceThe purpose of this study is to illustrate the potential of dry reforming of methane for industrial applications by producing synthetic fuels from the combination of dry and steam reforming of methane. The proposed process includes four main units: production of synthesis gas from the dry and steam reforming of methane, Fischer Tropsch synthesis, hydro-cracking of Fischer Tropsch waxes, product upgrading and hydrogen recovery. Simulation model of this process was carried out with Aspen Plus" software which allows us to define and analyze the optimum conditions and equipment specifications for each unit. Energy consumption and CO2 balance are also calculated. The main interest of our proposed process is its very favorable carbon balance

Power-to-Gas Storage Optimization Through Power Pinch Analysis

International audienceThis work focuses on the optimization of an innovative power storage technology Power-to-Gas using pinch analysis. The concept of Power -to-gas storage is the conversion of power into gas that can be stored in the natural gas network. This concept incurs considerable power losses compared to other storage technologies. Besides, it has a long start time and a long stand-by recovery time that need to be studied. Graphical and numerical approaches have been developed for power optimization. A first graphical approach is presented. Then a numerical approach will facilitate more targetedresponses to the problems experienced with the graphical one. This work acknowledges losses of the rectifier AC (alternating current) to DC (direct current), of the inverter (DC to AC), of the charging and the discharging process. This work proposes a new approach of Pinch Analysis Method for the optimization of Power-to -gas storage of a hybrid power system using intermittent and renewable energy. Graphical and numerical tools take into consideration new parameters (standby time, start time) and were applied to determine: • The temporal time ratio of charging, discharging, stand-by time and rest;• The minimum of outsourced electricity and the maximum of storage capacity.Different scenarios for energy farms are presented and allow the designers to choose the best alternative for energy systems in a French City. Results show that the best alternative is an onshore wind farm. A sensitive analysis allows us to apprehend the importance of the source’s type in the optimization of the storage system

Procédé de génération d'une atmosphère polluée contrôlée pour l'étude de la qualité de l'air habitacle des véhicules

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