Rumo a um futuro com baixas emissões de carbono: Tecnologia solar híbrida para a captura e utilização de CO2 biogénico

The main goal of the SunTech4CCU project is to develop a cutting-edge solar-powered technology based on photo-thermocatalytic membranes to foster biogenic CO2 capture and utilization (bio-CCU) towards biogas-to-biomethane (bioCH4) upgrading. CO2 from the biogas (a CO2/CH4 mixture) will be used as a backbone for generating additional bioCH4, or renewable natural gas, by photo-thermal methanation using green hydrogen, thus reducing net carbon emissions into the atmosphere. The proposed hybrid technology will unprecedently incorporate highly active plasmonic-based photo-thermal catalysts within a continuous-flow tube-in-tube membrane reactor coupled to a medium-concentrating sunlight collector to foster bio-CCU in a single unit. Ultimately, this technology will be validated towards upgrading biogas from two relevant sources, a sanitary landfill and an urban wastewater treatment plant (WWTP), which favors a technology readiness level (TRL) of 5, advancing beyond the research phase toward scalable implementation. The novel technology is designed to be green, robust, versatile, scalable, and potentially able to attain enhanced solar-to-fuel energy conversion, aiming as a key performance indicator a bioCH4 stream purity close to 100%. To accomplish the general purpose, five partial objectives will be addressed: (i) conception/application of novel structured photo-thermal catalysts grounded on plasmonic metals, featuring high UV-Vis-IR light response, CO2 adsorption capacity and selectivity/activity to convert CO2 into CH4; (ii) implementation of catalyst deposition methods for the preparation of nano-enhanced photo-thermocatalytic membranes; (iii) design/construction of a pilot-scale continuous-flow disruptive system composed of a tube-in-tube membrane photoreactor coupled to a concentrator solar collector, presenting low mass and photon transfer limitations; (iv) evaluate the permeability and selectivity of hollow polymer fibers for CO2/CH4 separation; and (v) application of the hybrid solar technology for biogas upgrading through CO2 hydrogenation into bioCH4, under synthetic and real conditions. Accordingly, the SunTech4CCU project tackles several critical global challenges, including reducing greenhouse gas emissions, optimizing renewable energy utilization, reducing dependency on fossil fuels, and transitioning innovative concepts to practical applications. By focusing on converting biogenic CO2, which is typically emitted to the atmosphere during conventional biogas upgrading/combustion processes, into renewable natural gas via solar-driven methanation at a TRL of 5, the project aims to accelerate the transition towards sustainable and scalable solutions for biogas upgrading and carbon utilization. Moreover, the project’s objectives push the boundaries of existing knowledge and technology to develop novel concepts and approaches that go beyond the state of the art. Integrating photo-thermal catalysis with membrane and solar energy harvesting devices for the first time, the project adopts an unprecedented multidisciplinary approach that transcends traditional CCU limitations, combining expertise from diverse fields, including catalysis, membrane separation, materials science, and renewable energy engineering. Also, while many studies focus on lab-scale demonstrations, SunTech4CCU sets the technology validation in real-world environments, going beyond typical laboratory research and emphasizing its practical applicability/scalability.