Desenvolvimento e avaliação do uso de eletrodos porosos de níquel para produção de hidrogênio eletrolítico.

Abstract

Non-renewable sources, especially those of fossil origin, make up the bulk of the world's energy matrix, a fact that has been causing serious environmental damage to the environment. As a solution, renewable energy sources have gained notoriety and are currently generating efforts and high investments to occupy more space in the energy supply. The H2 presents itself as a large clean and renewable energy vector. Therefore, researches must be developed to make it, in fact, an energetic reality. It is in this sense that this work had as objective to develop an electrolytic system, composed with porous nickel electrodes, aiming to study the performance and the economic balance for the production of H2 under different electrical potentials and concentrations of electrolytic solution. With that, the technical behavior of the electrolytic system in the production of H2 was evaluated and were identified/interpreted is electrochemical phenomena that occurred in the alkaline electrolysis with the porous electrode of nickel. Morphological analysis of the studied electrode and economic analysis of the hydrogen produced by the developed system were also performed. The system composed of nickel porous electrodes performed better with low concentration KOH electrolyte solutions and potential of 4.0 V. Under these conditions the average H2 flux produced by the system was equal to 5.48 NL/h for a power of 24.64 W and a faradic, thermal and thermodynamic efficiency equal to 61.5%; 74.0% and 78.7%, respectively. Statistically, it was observed that only the potential applied to the developed electrolytic system has a significant effect on H2 production. The electrolytic system developed in this study consumed 3.94 kWh to produce 1.0 m3 H2 and had a total investment cost of US $ 80.13. The cost of the source the power hydrogen varied between 0.79 – 0.15 US$/kWh using renewable sources (hydraulics, solar and wind) and for a period of operation of 4380.0 h/year over ten years of amortization. The results showed that the use of renewable electricity is an important point to reduce H2 costs and also to integrate large amounts of variable renewable energy in the global energy matrix, corroborating with the literature. The results also prove the optimum efficiency obtained with the use of nickel porous electrodes in electrolysis.