Do resíduo à solução: fechando o ciclo da produção de hidrogénio

The major goal of this project is to explore the viability and sustainability of producing hydrogen through the gasification of solid residues, solving two issues at a time: managing wastes and producing renewable energy. This will be achieved by modelling and testing the production of syngas with an innovative quality index in agreement with the required values for the specific purposes of H2 application, and then evaluating the environmental and socioeconomic impacts of the production route to ensure a firm compromise to the maximum involved fronts amid sustainability aspects. To do so, a combined effort among numerical simulation, bench-scale and pilot-scale experiments, followed by a sustainability assessment to better inform about the performance of the system will be put forth. With this, not only technological developments are envisioned, but intangible advancements, knowledge transfer and new collaborations are also expected. This approach aims to help tackling a dual problem: efficiently managing waste, while achieving a marketable and multipurpose energy-vector, the synthetic gas (syngas), that may be conveniently tailored to present an H2-enriched profile. Hydrogen is a promising asset for various economy and industry sectors (for instance fuels, transports, and chemicals), therefore its production in a sustainable manner is highly welcomed. To do so, an evolved thermal waste conversion technique will be used – gasification. Gasification is a thermochemical process that transforms solid streams into energy through a self-sufficient autothermic mechanism. Operating at high temperatures and in the presence of an oxidizing agent (such as steam, air, oxygen, CO2, or their combinations), gasification initiates a series of chemical reactions, that yield a blend of combustible gases, along with minor amounts of char, ash, and condensable compounds collectively known as syngas [22]. Syngas is a versatile product that can act as a hydrogen carrier, among other possibilities. Distinct steps occur during gasification: drying, pyrolysis, oxidation, and reduction zone [17]. Oxidation is the stage where syngas quality index is established, factors like the gasifying agent, pressure, and temperature being crucial in determining its suitability for powering gas engines, gas turbines, or for fuel production [25]. There are some challenges associated to this strategy, namely the need to consider pre-treatment steps according to the characteristics and composition of the feedstock, as well as tar prevention/removal strategies for some specific residues or blends that can constitute obstacles to a cleaner and proficient waste conversion [2]. To overcome this, a mapping of the best samples will be conducted, crossing their characterization with the desired syngas quality, through machine learning (ML). Scarce literature exists dealing with syngas quality and these methods (even fewer works reported for non-fossil sources), only one work studying this specifically for H2 production [26]. Besides constituting a contribute to decarbonization, auspicious steps in the direction of sustainability will be given while replying to current societal, industrial and technological needs. This will progressively and ultimately lead to the replacement of fossil-based options in several applications, while also improving the performance of the waste management and hydrogen sectors among all the other areas that can profit from H2 production and usage.