Avaliação e comparação de modelos matemáticos para produção de H2 verde via eletrólise PEM

Abstract

Considering the growing demand for green hydrogen in the current decarbonization scenario, coupled with the promising performance of PEM (Proton Exchange Membrane) electrolysis in aspects such as design, operating current densities, efficiency, response time, and hydrogen purity, the need for in-depth studies on the phenomenology, modeling, and simulation of this process becomes evident. In this context, this work focuses on the mathematical modeling of the PEM electrolysis process for hydrogen production, with special attention to proton conductivity and the development of simulation and analysis software. The research presents a critical review of existing mathematical models, highlighting limitations and significant deviations in results due to simplified assumptions and considerations used by different authors. A more in-depth comparison between the different approaches found in the literature showed, for example, that empirical and semi-empirical modeling have deviations of up to 8.4% and 14.3%, in terms of voltage, relative to phenomenology, respectively. In response to this - and with a focus on the proton conductivity phenomenon - an adjustment to a widely used semi-empirical model in the literature is made, and furthermore, a new pseudo-empirical model based on pseudo-experimental data obtained from a phenomenological model is developed, aiming for a more effective balance between simplicity and accuracy. Both developed models showed errors below 4% and R2>0.99 at room temperature (298.15 K), however, they exhibited different performances at typical operating temperatures in PEM electrolyzers (333.15 K - 353.15 K), highlighting the need for more in-depth experimental analysis regarding conductivity at relative high temperatures. Furthermore, a software was developed in Visual Basic for Applications (VBA) incorporating all the modeling presented and reviewed in the work. This software enables simulations and detailed analyses regarding losses related to various phenomena present in the process, providing valuable insights for optimizing the hydrogen production process. In conclusion, through this work, it was possible to develop mathematical modeling and a simulator for the Green H2 production process via PEM electrolysis, offering new paths for optimizing such systems and for studying the use of polymeric membranes as electrolytes. Thus, the results not only assist in advancing the theoretical understanding of the PEM electrolysis process but also provide practical tools for research and development in the sector.