At the end of the project a demo plant at TRL6 was developed, manufactured, interconnected and tested at Kamari Plant of Titan Cement Group. Four units were built aiming the CO2 capture and its further conversion to nanoCaCO3, formic acid, oxalic acid and glyoxylic acid.
The development of new CO2 separation processes for industrial flue gases is based on the application of ILs. In total 30 ILs were developed an tested for the CO2 purification from the cement plant flue gas, 5 of them were tested at TRL4 in a miniplant and 1 was selected for the final demo campaign, based on [EMIM][OAc]. The basic design of the CO2 separation plant as well as for the gas pre-treatment and after-treatment was designed to treat 100 Nm3/h of gas. Their were tested at the TRL6 scale reaching up to 90 % of CO2 purity in the outlet, with a flue gas containing 10%v/v of CO2.
The first route for conversion of CO2 proceeds with the design and optimization of nano CaCO3 synthesis precipitation process using different reactors. Two different approaches were used in order to provide a full range of options for the final process layout. The 2 reactors were designed and tested at TRL 6: Packed Bed Reactor and Membrane-Based Precipitator, at the target productivity of 3 kg/h of CaCO3. Finally, the downstream separation and purification processes were studied, designed and manufactured in order to crystallize and recover NH4Cl as an added-value side-product of the process. From the demo campaign, cubic calcite crystallites with tuneable size of 50 - 65 nm were obtained at TRL5 and TRL6. There were few differences between the 2 reactors in terms of product quality, achieving a high purity and potentially marketable product.
The second route for conversion of CO2 consist in the electrochemical conversion. This part of the project is higly complex because several process were studied and integrated in the final pilot plant. For the first electrochemical process for the conversion of CO2 to Oxalate, it was also developed a CO2 Compression / dissolution system, which was manufactured and tested with organic solvent at TRL5. With this system, a reduced overall specific energy consumption of 46% was demonstrated with respect to the current technologies for dissolving CO2 in liquid solvents. At the end of the project, optimized electrocatalysts / electrodes for the CO2 reduction were developed, attaining the RECODE targets at TRL4 scale: at 50 – 100 mA/cm2 (higher than the target) with electrodes size higher than the original target of 10 cm2. Overall, 2 electrochemical cells (for 3 reactions) were scaled-up. The reactions are: 1) CO2 to formic acid production: a stack of 6 cells with a total of 0.6 m2 (electrodes of 0.1 m2), to achieve a designed production scale of 0.5 kg/h; 2) Oxalic acid to Glyoxylic acid production: a stack of 2 cells with a total of 0.2 m2 (electrodes of 0.1 m2), to achieve a desingned production scale of 0.2 kg/h; and 3) CO2 to Oxalic acid production: a single cell of 0.1 m2, to achieve designed production scale of 0.05 kg/h.
In addition, a catalytic process for the conversion of Glyoxylic acid to Glycine was also developed at TRL$ scale, achieving a productivity of 0.021 kg/(h L), which is scalable to higher scales with commercial reactors and exploiting the RECODE developed catalysts.
Several dissemination activities were developed in parallel to the technical and scientific progress of the project. All the partners have contributed with dissemination and communication activities focusing on different stakeholders. An open Access repository of the project results is in Zenodo at:
https://zenodo.org/communities/recode/?page=1&size=20(opens in new window). The projevct partners participated to several national and international events, do Networking and clustering activities with other EU projects. it was created at EU projects related to CCU, including RECODE. TITAN also leads communication activities focused on industrial stakeholders and cement industries. training activities were performed during the project such as 2 editions of the Co2oling the earth summer schools held in 2020 and 2021. More info is available in the project website.
