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Cost-effective CO2 conversion into chemicals via combination of Capture, ELectrochemical and BI-ochemical CONversion technologies

Periodic Reporting for period 3 - CELBICON (Cost-effective CO2 conversion into chemicals via combination of Capture, ELectrochemical and BI-ochemical CONversion technologies)

Período documentado: 2018-09-01 hasta 2019-11-30

The conversion of CO2 into valuable chemicals by the use of renewable energy is an strategic goal for the sustainable development of the society in the near future. It will entail the reduction of greenhouse gas emissions, but also the generation of renewable compounds substituting fossil ones. CO2 generation from e.g. fermentation processes will offer excellent application opportunities for this concept, owing to their rather high carbon dioxide concentrations and their favorable chemical context (i.e. pure CO2 from alcoholic fermentations in bio-refineries, distilleries, etc.; biogas from anaerobic fermentation or landfills, containing 20-45 % CO2). However, a significant impact of the CO2-to-chemicals future processes will be achieved only if viable CO2 capture/purification technologies from the atmosphere or flue gases will be developed.

In that context, the CELBICON project aims at the development, from TRL3 to TRL5, of new CO2-to-chemicals technologies, conjugating at once small-scale for an effective decentralized market penetration, high efficiency/yield, low cost, robustness, moderate operating temperatures, low maintenance costs and high versatility to be adapted to the synthesis of a variety of chemical products.

The core goal of the Celbicon project is to ultimately produce high-value chemicals with a very low, or even negative, carbon footprint. This is done by capturing CO2 from the air and converting it to complex, valuable chemicals. The CO2 is converted by a sequence of electrochemical and biochemical steps. The energy required for the conversions can ultimately come from sustainable energy sources. More specifically, three reaction lines are performed (see Fig. 1). In the first reaction line (technological platform 1, TP1), after capturing CO2 from the air, it is electrochemically converted to high pressure syn-gas (CO and H2) and the oxidation of renewable chemical in a high value acid. Then, in technological platform 2 (TP2), the syn-gas is biochemically converted at elevated pressure to building blocks for bioplastics. In this biochemical conversion some CO2 is emitted again but it is recovered, together with excess captured CO2 from air, to be then converted in a second high-pressure bio-reactor to bio-methane. In the third reaction line (technological platform 3, TP3) demineralization of wastewater is done at the same time that air-captured CO2 is electrochemically converted to formate, which is subsequently biochemically converted to large valuable compounds, such as isoprenes.
Within the 45 months of the Celbicon project it was possible to fully develop (by research and engineering), assemble and test the TP1 and TP3 platforms at TRL5, demonstrating the feasibility of the integration of technologies for the CO2 capture from air and its electrochemical conversion to syn-gas and formate products. These reactions were coupled to another useful oxidation (i.e. the oxidation of furfural into fuoric acid in TP1 or the demineralization of biological wastewater in TP3). An important outcome of the project is that these electrochemical platforms can be operated in a wild range of conditions, allowing the screening of many other potentially attractive electrochemical reactions and catalyst materials. Figure 2 shows the TP1 platform at AVT facilities: From left to right: unit for CO2 capture from air, Electrolyte tank, CO2 compression and water dissolution system, electrochemical system for CO2 conversion to syn-gas and the oxidation of furfural into fuoric acid. A video explaining this demo plant is visible at: https://youtu.be/C32qm8U2B0E.
Among the bio-technological processes of TP2, a final scale-up was possible only for the biomethanation one, which reached unprecedent productivities at a TRL5 demo plant. In Figure 3 is shown a skid of the pressure resistant bioreactor system developed by Krajete in collaboration with Hysytech that was used for the technological platform 2 (TP2). A short video of the TP2 processes can be seen at https://www.youtube.com/watch?v=_0tqGBwMtCg.

Celbicon developments have been disseminated through Open Access publication in international peer-review journals, mass-media, at international conferences, workshops and other public events (see www.celbicon.org/Pages/content.aspx?oid=35).
New technological advances are necessary to replace the fossil fuels and chemicals with green alternatives that produce low-to-no CO2 during utilization. From the economic, energetic, and environmental viewpoints, the conversion of CO2 using renewable resources to produce clean fuels and chemicals is a viable solution to meet the growing demand of Europe and the entire World.
In this context, Celbicon have clearly developed at least 3 technologies up to a stage where they can be commercialized: 1) direct CO2 capture from air, 2) an energy efficient method to compress and dissolve CO2 in water to obtain high-pressure, concentrated CO2 solutions, and 3) biochemical production of methane from CO2 and H2. The first technology of CO2 capture developed by Climeworks reached a TRL 6 and was completely integrated in a carbon capture and utilization (CCU) process, exploiting two prospective renewable electricity-driven electrochemical processes aimed to convert the atmospheric CO2 to useful chemicals. The second functional and automated prototype for CO2 compression and dissolution was developed and manufactured at TRL 5 level by KIT and Cubogas, achieving approx. 40% reduction of energy demand in comparison to the standard process (first gas compression and then dissolution at the high-pressure level). This result was achieved by evaluating the optimal operating parameter combinations of water atomization and compression curves, leading to maximization of the interface between the gaseous and liquid phase in a commercial piston compressor which was customized to be optically accessible for these developments. The third bio-chemical process achieved continuous and intermittent CO2 conversion in the presence of hydrogen and CO generated in electrolyser I (TP1) to methane at TRL5 in a custom integrated pressure resistant bioreactor (see Fig. 3), able to operate from ambient pressure to 50 barg. Multiple methanogenic strains (from mesophilic to hyperthermophilic domain) for CO2 conversion to CH4 were screened. This, together with the high-pressure operation, allowed to break kinetic barriers and reach unprecedent CO2-to-CH4 productivities.

Other important research outcomes have been achieved for innovative processes such as: the high-pressure biochemical conversion of syn-gas to bioplastics (PHA) with bioengineered microorganisms studied by POLITO and CISIC, extraction of PHA with green solvents; new electrocatalysts and membrane materials for the electrochemical CO2 conversion and waste water treatment (by POLITO, TUD, UMON and the F- IGB).

CELBICON will produce an impact, via innovative technologies for the exploitation of decentralised CO2 in the synthesis of green chemicals and biopolymers with: i) near-to-zero greenhouse gas emissions and ii) cost competitive conditions compared to fossil alternatives.