Technology description
Pillar II
Gasification
Gasification is an endothermic process where carbon-based feedstocks (like biomass and waste) are converted at high temperatures (750-950°C). This produces syngas, a mixture rich in H₂ and CO, which can be used for energy or chemical synthesis. Fluidized bed gasification is a mature technology for simple biomass like wood (TRL 7-9), however, it faces challenges with complex feedstocks, which contain impurities such as inorganics and pollutants. Issues arise from: (i) feedstock preparation, (ii) pollutant behavior (iii) reactor fouling/agglomeration due to inorganics, and (iv) particle-level biochar production. Fuels-C aims to validate complex feedstock gasification at TRL5, as a first step to produce Formic Acid and etanol.
Microbial Electrosynthesis
Ethanol will be produced from CO₂ (from biogas or syngas) using a microbial electrosynthesis platform powered by surplus renewable energy. Particularly in complex microbial communities like those employed in Fuels-C, ensuring electron flow to all biofilm members becomes pivotal to augment energy conversion and CO₂ fixation. To address this, the project will investigate the integration of suspended conductive materials as a strategy to enhance cell-to-cell contact and electron flow in laboratory-scale reactors. In the context of Fuels-C, a syntrophic consortium comprising H2-producers (i.e., Desulfovibrio paquesii and Desulfovibrio vulgaris within the biofilm is coupled with carboxydotrophic species such as Clostridium species or Eubacterium Limosum to facilitate ethanol production.
Electroreduction
Formate is a common product from CO₂ electroreduction. The Fuels-C project aims to directly produce formic acid from CO₂ in a novel reactor setup, using high-performance advanced gas diffusion electrodes (GDEs). The key challenge is suppressing the competing hydrogen evolution reaction (HER), especially in a high-proton environment. VITO’s optimized process achieves CO₂-to-formate conversion with >85% efficiency over 3000 hours, and the formate is then acidified to formic acid. To enhance this process, VITO will refine electrolyte selection (e.g., sulfuric acid, formic acid, ammonium bicarbonate) and explore optimal membranes (such as Fumasep® and Sustainion®) to maintain efficient ion transfer and reduce potential drops across the cell.
Pillar III
Bioelectrochemically Assisted Anaerobic Digestion
Bioelectrochemical systems (BES) can enhance biogas production rates and quality in anaerobic digesters (AD), although yields vary based on feedstock. Electro-methanogenesis (EMG) has shown potential for upgrading biogas by converting residual CO₂ to CH₄ with lower energy consumption than conventional methods, and it could serve as a novel power-to-gas strategy for storing renewable energy. However, combining AD-BES with EMG for biomethane production is still in early stages and reliable AD-BES performance beyond lab conditions has yet to be proven. Fuels-C aims to advance biomethane production by refining AD-BES and EMG processes, by using new reactor architectures to reduce overpotentials, match anode-cathode kinetics and improve mass transfer.
Electromethanogenesis (EMG)
Ethanol will be produced from CO₂ (from biogas or syngas) using a microbial electrosynthesis platform powered by surplus renewable energy. Particularly in complex microbial communities like those employed in Fuels-C, ensuring electron flow to all biofilm members becomes pivotal to augment energy conversion and CO₂ fixation. To address this, the project will investigate the integration of suspended conductive materials as a strategy to enhance cell-to-cell contact and electron flow in laboratory-scale reactors. In the context of Fuels-C, a syntrophic consortium comprising H2-producers (i.e., Desulfovibrio paquesii and Desulfovibrio vulgaris within the biofilm is coupled with carboxydotrophic species such as Clostridium species or Eubacterium Limosum to facilitate ethanol production.
BES-mediated Nitrogen Recovery
Most BES reactors for nitrogen recovery rely on the transport of NH4+ across a cation exchange membrane (CEM), which is driven by the electricity generated during the degradation of organic matter in the bioanode. A N recovery process that is independent of the transport of NH4+ across the CEM to the catholyte chamber would facilitate operation and reduce energy loss. Fuels-C proposes a pioneering approach to recover nitrogen from liquid digestates using BES, in a way that can be directly used in fuel cells (FCs). This consists of a reactor configuration where the N-rich stream is directly used as the catholyte. This eliminates the need for selective transport of NH4+ ions through a CEM. It also eliminates the need for biofilm acclimation to high NH4+ concentrations.
Pillar IV
Solid Oxide Fuel Cells
Solid oxide fuel cell (SOFC) is an electrochemical device operating at a high temperature, converting the chemical energy of a fuel directly to electrical energy. Moreover, it can directly convert hydrocarbon fuels to a hydrogen-rich gas via internal reforming inside the fuel cell stack itself.
Direct Liquid Fuel Cells
Ethanol will be produced from CO₂ (from biogas or syngas) using a microbial electrosynthesis platform powered by surplus renewable energy. Particularly in complex microbial communities like those employed in Fuels-C, ensuring electron flow to all biofilm members becomes pivotal to augment energy conversion and CO₂ fixation. To address this, the project will investigate the integration of suspended conductive materials as a strategy to enhance cell-to-cell contact and electron flow in laboratory-scale reactors. In the context of Fuels-C, a syntrophic consortium comprising H2-producers (i.e., Desulfovibrio paquesii and Desulfovibrio vulgaris within the biofilm is coupled with carboxydotrophic species such as Clostridium species or Eubacterium Limosum to facilitate ethanol production.