CENER will valorise the CO2 from the fast pyrolysis off-gas subjected to catalytic hydrotreatment in ABATE project

In the framework of ABATE Horizon Europe project, CENER in its the Biorefinery and Bioenergy Center BIO2C, will valorise the CO₂ from the fast pyrolysis bio-oil subjected to catalytic hydrotreatment by means of a bioconversion to methane with a mixed culture.

Energy security is a pivotal concern for the European Union as it seeks to mitigate reliance on fossil fuel imports while transitioning toward a sustainable energy system. The volatility of global energy markets, coupled with geopolitical tensions, underscores the necessity for resilient and diversified energy sources. Intermediate bioenergy carriers, including bio-oil, torrefied biomass, and biogas, offer a promising renewable alternative by enhancing the storability, transportability, and usability of biomass-derived fuels, and facilitate integration into existing energy infrastructure.

For that reason, Horizon Europe project ABATE project aims to demonstrate the integration of thermochemical and biochemical technologies to valorise biomass into cost-competitive, carbon-neutral advanced bio-based intermediates to directly substitute fossil fuel hydrocarbons in conventional oil refineries. The ABATE consortium will build on existing research conducted in the Horizon 2020 BioMates project which validated a two-step valorisation process for lignocellulosic biomass at TRL 5. This provides a robust foundation for further technology scale-up and demonstration in the ABATE project.

In further detail, residual lignocellulosic biomass is first converted into fast pyrolysis bio-oil (FPBO) and biochar. The CO₂ produced during the FPBO manufacturing process will be captured and converted into methanol, thereby reducing GHG emissions from the pyrolysis stage. The FPBO is then stabilised into a high-quality advanced bio-based intermediate, which can be directly fed into conventional refinery units. The stabilisation will be performed via a single hydroprocessing step enabled by a novel catalytic system which incorporates several innovative systems and designs and efficiently integrated with green hydrogen production and biological carbon capture and utilisation (CCU) through biomethanisation.

CENER’s objective within the project is to treat the entire residual H₂ stream from the hydrodeoxygenation reactor (HDO) and convert at least 90% CO₂ into methane within a trickle-bed reactor. The maturity of level of the trickle bed bioreactor was demonstrated at TRL 5 during the BIOMETANOGENESIS project, where the bioreactor was designed, constructed, and operated successfully. Subsequently, in Advanced Biofuel Development Laboratory project, the bioreactor was upscaled, resulting in fully automated reactor with an increased CO₂ processing capacity and capable of precise and consistent control over various parameters such as temperature, pressure, flow rates, and gas concentrations. The operation of this bioreactor will be demonstrated at TRL 6 within the ABATE project. This transformation of CO₂ is carried out by means of a bioconversion to methane with a mixed culture, a process in which it is intended to study:

• The evolution of the microorganisms through specific adaptation to gas substrate, as well as to contaminants, thus achieving: a reduction in the start-up time of production while increasing the yield and reducing the possible inhibitory impact of the components present in the gas substrate.
• The operation optimization in a trickle bed reactor (TBR), adapting the microorganisms to the working pressure, observing the effect of the H₂/CO₂ ratio, the gas retention time (GRT) and other parameters such as pH and temperature.
• The scaling up of the biomethanation process in a 100 L capacity TBR. Carrying out three tests lasting 30 days each.

After 6 months of project execution, the state of development achieved so far by CENER in relation to the evolution of methane-producing microorganisms to HDO-off gas is extremely positive. On the one hand, it has been evaluated that no inhibition has been detected due to the presence of potential inhibitors such as H₂S, ethane, propane, butane, pentane, etc., which are concomitant with the generation of HDO-off gas during the hydrogenation of the bio-oil derived from pyrolysis. On the other hand, it has been demonstrated that methane-producing microorganisms can grow based on the very low CO₂ content (2.5% v/v) contained in the HDO waste gas, while producing methane. At this point in the development, further research is being carried out with continuous trials, with the aim of evolving the methanogenic micro-organisms to show better behaviour with HDO-off gas.

Thanks to the ABATE research and development project, CENER strengthens its commitment to innovation, sustainability and energy decarbonization improvement, positioning itself as a benchmark in biorefining applied to global challenges.

ABATE funded by Horizon Europe, officially started activities on 1 September 2024 and will run for four years. The consortium coordinated by CERTH, comprises 14 partners from 10 countries (BP Europa; Topsoe; Fraunhofer UMSICHT Oberhausen; IFEU; Imperial College London; Greenovate! Europe; RISE; Pyrocell; Vinci Technologies; RE-CORD; CENER, University of Chemistry and Technology Prague).