Processo integrado utilizando tecnologia de captura de água para produção de hidrogénio e valorização em metano de CO2 biogénico

The primary aim of this project is to design an integrated process capable of upgrading a biogas stream and further converting the captured CO2 into e-CH4, tailored explicitly for its integration with a typical biogas anaerobic digester with a production capacity of 100 Nm3/hr of biogas. A secondary objective is to maximize the electrification of the process to diminish reliance on fossil fuels. To accomplish these goals, the project outlines three pivotal sub-objectives. The first sub-objective focuses on designing an atmospheric water harvesting unit aimed at producing sufficient water to facilitate H2 production. This unit should yield approximately 4300 liters of water per day, requiring the development of a suitable hybrid adsorbent with high water adsorption capacity and adequate electrical properties to be heated by Joule effect, permitting the implementation of an efficient Electric Swing Adsorption (ESA) process. The second sub-objective revolves around the daily production of approximately 350 kg of hydrogen. This entails the design of an efficient electrolyzer system and an associated hydrogen purification process to ensure the purity requirements, since the obtained hydrogen stream will be humid and can also have other contaminants (e.g. oxygen). For the purpose, a dedicated adsorption-based separation unit will be designed. The third sub-objective involves capturing and converting approximately 1900 kg of biogenic CO2 into e-CH4. This task is intrinsically tied to developing bifunctional materials capable of adsorbing CO2 at low to moderate temperatures and, subsequently, catalyzing its conversion into methane at higher temperatures. By successfully addressing these sub-objectives, the project aims to realize a complete and electrified process capable of efficiently capturing and utilizing CO2 while promoting the local production of water and hydrogen, reducing environmental impact and stress in local resources, such as freshwater bodies. In addition to the primary and secondary objectives, a final objective of paramount importance is to conduct a comprehensive analysis of the entire process, focusing on energy consumption, CO2 footprint, and economic feasibility. This analysis will prioritize promoting energy integration among the various units to enhance overall energy efficiency. For instance, one potential strategy involves harnessing excess heat from the electrolyzer to pre-heat the hydrogen stream before entering the capture/conversion unit. By systematically evaluating energy utilization, carbon emissions, and economic viability, the project seeks to optimize the process's sustainability and commercial viability. Through innovative energy integration techniques and meticulous economic assessments, the aim is to establish a robust framework for successfully implementing and operating the CO2 capture and conversion process. This holistic approach underscores the project's commitment to achieving environmental and economic sustainability in pursuing cleaner energy solutions.