Reactor de cámara única para la generación de hidrógeno a partir de residuos orgánicos

Abstract

[EN] Nowadays, energy sector follows the guidelines addressed basically by the economicfinancial system that supports the generation and use of fossil fuel having serious environmental and economic consequences. The main goal of current research is the search of possible alternative energy resources, such as the hydrogen, respectful with the environment, at a reduced cost. With this aim, an electrolytic system assisted by an organic compound is proposed for hydrogen generation at room pressure and temperature A single cavity reactor has been specially designed and developed to produce high purity hydrogen, having an innovative fluid circulation system. The single cavity reactor can be used in electrolysis processes of alkali solutions provided that organic compounds are present, as the oxygen reacts with the carbon present in the graphite electrodes and organic compound, and almost disappear from the generated gasses flow, where hydrogen appears in a percentage close to 98% under specific operating conditions. The organic compound investigated is glycerine, as its valuation in the electro-oxidation process, both of the gas and fluid phases, makes glycerine an excellent candidate, due to the existence of great excesses of industrial glycerine from the biodiesel production industry. The effect on the hydrogen production of several variables is analyzed. Among them are the electrodes material, geometry and catalyst, and the alkali agent and organic compound concentrations in the analyzed aqueous solution, to determine optimal operation conditions. The electrochemical characterization of the electrolytic process is accomplished through polarization curves and impedance spectra, using also gases chromatography for the gas phase and highperformance liquid chromatography (HPLC) and mass spectrometry for the liquid phase. The organic compound reduction is also investigated, through the value of the chemical oxygen demand (COD), at different times of the electrolysis process, thus to get a more complete valuation. A monitoring and control system, sensor based, is proposed for real time automation of the optimization electro-oxidation process. Finally, the expert knowledge acquired all over the experimentation, extracted from numerous tests (examples), is modeled according a reasoning systems based on a decision tree, to determine the actions to be performed. Control strategies are developed to optimize both high volume production of high purity hydrogen and high reduction of the solution organic compound. All experiments are performed at the Renewable Energy, Fuel Cells and Hydrogen Laboratory (LERH), at the Centre for Automation and Robotics (CAR_CSIC_UPM) facilities in the Arganda del Rey (Madrid) campus. From the accomplished research it can be concluded that both the proposed electrooxidation process and the novel reactor designed, allow the production of hydrogen of high purity with almost lack of other gases, such as O 2, CO, CO2, CH4, at a reduced cost compared with those of the conventional electrolytic systems. On the other hand, with the electrooxidation process, a high reduction of the organic compound in the liquid phase is achieved, of great environment and economic significance. The research presented in this Doctoral Thesis, displays an interdisciplinary nature, according with current society and industry challenges, strengthen both by the I+D+i National and EU H2020 research programs devoted to the Society Challenges. Both formulate as one of the main society challenges the topic: “Safe, Efficient and Clean Energy”