ICO2CH

Goal

An integrated process concept is proposed for low-cost, post-combustion CO2 capture and renewable H2 production, with O2 co-generation. The core innovation intensifies electrolysis of aqueous electrolyte that contains (bi)carbonate, as output stream from the aqueous KOH-based capture step. By this way, no dedicated ‘stripping’ energy is required, KOH capture agent is regenerated together with H2 evolution and O2/CO2 valorised via oxy-fuel combustion and H2-mediated CO2 conversion, respectively after separation.

In the ICO₂CH project, an integrated concept is investigated for the low-cost capture from CO₂ point sources with alkaline KOH-based media and renewable H₂ production. The innovation is on the level of the water electrolyser, which is fed by a CO₂-rich, post-capture (bi)carbonate solution, that enables isolation of a 80:20 % CO₂/O₂ gas mixture from the anolyte during operation. This eliminates the need for dedicated ‘stripping’ energy, since CO₂ liberation is a consequence of OH- consumption during O₂ production. Simultaneously, KOH is regenerated in the H₂ evolution reaction, avoiding further capture utility costs. The high-purity CO₂ stream can be valorized, in combination with H₂ to produce e.g. synthetic fuels, next to O₂ in (partial) oxy-fuel combustion, after a final CO₂/O₂ separation step.

The scientific goals are related to performance targets that enable low electrolyser cost levels (CAPEX ~current density, AWE: 600 - 1200 €/kW) with minimal impact on OPEX (electricity use/efficiency ~cell potential). This will be pursued by the development and stacking of 3D-thin-film components (VITO – Imec), to (1) compensate decreased ionic conductivities compared to typical KOH-based electrolytes and (2) maximize the effectiveness of pH change at the anodic side. Therefore multiphase models are used to link electrochemical reactions and transport phenomena to the bulk chemistry, while process modeling and application testing is involved in the evaluation of CO₂/O₂ separation (VUB) and integration with an oxy-fuel combustion step (KUL). The project is supported by research-directive models and advice (VITO), based on techno-economic principles and benchmark analysis.

The key exploitable results encompass devices and process-based innovations, addressing producers of electrocatalysts, electrodes and membranes, next to process developers, for valorization. The end users of such capture technology are present in the refining, chemical, steel and energy sectors, having unavoidable CO₂ point source emissions and optionally interest in (partial) oxy-fuel combustion. This also involves companies (or clusters) interested in CCU/Power-to-X applications with access to high-purity CO₂ and H₂, as produced in one intensified system.