DBD plasma reactor for CO2 methanation
- Autores: Martí Biset Peiró
- Directores de la Tesis: Teresa Andreu Arbella (dir. tes.), Joan Ramon Morante Lleonart (tut. tes.)
- Lectura: En la Universitat de Barcelona ( España ) en 2022
- Idioma: inglés
- Tribunal Calificador de la Tesis: Katherine Villa Gómez (presid.), Marc Torrell Faro (secret.), Federico Azzolina Jury (voc.)
- Materias:
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- Resumen
One of the most serious challenges facing society is the need to reduce the emissions of greenhouse gases such as carbon dioxide (CO2), mainly caused by the widespread use of fossil fuels. The energy transition to renewable energies is currently in its initial stages of its implementation. Due to the need to increase renewable energy sources, it is necessary to develop new technologies that can adapt the fluctuating generation of renewables with the energy consumption.
The conversion of CO2 into synthetic fuels using electrical energy, technologies known as Power to Gas, presents a solution to the energy storage. In the specific case of the methanation reaction, CO2 is converted to methane (CH4, synthetic natural gas), which can be stored and distributed in large quantities. In this way, synthetic natural gas is used as an energy vector, providing a solution as energy storage and as a method of CO2 valorization.
In the last years, Power to Gas technologies are being implemented in several pilot plants with conventional thermochemical technologies for the methanation reaction. In this regard, alternative methods to thermal catalysis are being studied, which could potentially have advantages in terms of conversion or reduction of energy costs, among others. The use of plasmas in the conversion of CO2 is particularly promising due to the ability of plasma to activate stable molecules such as CO2 or N2.
In this context, the aim of this thesis is the development of a dielectric barrier discharge plasma reactor for the conversion of CO2 to CH4, the development of catalysts for this reaction and the optimization of both the catalysts and the plasma reactor. Following these objectives, the thesis is structured in 6 main chapters. The first chapter presents the general context, the motivation of the research regarding CO2 conversion technologies and a basic introduction of plasma technologies. In chapter 2, all experimental setup and material synthesis are explained. The following chapters are focused on the main results obtained during the development of the thesis, which can be divided into two parts. The first part is focused on the catalyst evaluation for plasma-CO2 methanation (chapter 3 and chapter 4). The second part is focused on the optimization of the plasma reactor (chapter 5 and chapter 6).
In the catalyst evaluation for plasma-CO2 methanation, different types of catalyst were synthesized, physicochemical characterized and evaluated in thermal and plasma methanation. Operation temperature was reduced to 100-200 ºC in the case of plasma methanation. The effect of different catalysts composition and structure was analyzed. The incorporation of cerium in nickel based catalyst boosted the conversion and efficiencies. The different role of plasma activation and catalyst activity were evaluated.
In the second part, DBD reactor optimization, different reactor configurations were tested. The role of temperature was analyzed in pseudo-adiabatic and adiabatic DBD reactor. The use of adiabatic reactors allows to increase the energy efficiency. Finally, a new approach was evaluated based on using DBD-plasma as reaction ignitor, rather than the classical approach of continuous operation. After plasma ignition, the operation in autothermal conditions without any external energy input was evaluated. The new methodology allowed to faster start the reaction, due to the plasma activation at a lower temperature, minimizing the start-up time and the energy cost.
