Reactor design in carbon capture and utilization to produce cyclic carbonates using ionic liquids: Catalytic essays and techno-economic analysis

This work advances in the development of new carbon capture and utilization (CCU) technology to produce cyclic carbonates based on ionic liquids (ILs) through two main contributions: i) Experimental kinetic allowing rigorous reactor design and sizing at process scale for the first time; and ii) reliable techno-economic analysis (TEA) combined with life cycle assessment (LCA). The proposed CCU uses two ILs: CO 2 is captured from a pre-combustion stream using aprotic heterocyclic anion-based ILs (AHA-ILs) as a CO 2 chemical-physical adsorbent, and CO 2 conversion occurs using halide-ILs as a catalyst to produce hexylene carbonate (Hex C). A water-based liquid-liquid extraction strategy is proposed for IL/Hex-C separation. A multiscale research methodology, combining iterative computational-experimental approaches, is applied, integrating molecular modelling, catalytic tests, kinetic regression, phase equilibrium measurements, process simulation, TEA, and LCA. DFT/COSMO-RS screening selects [bmim][I] as optimal IL for the CO 2 cycloaddition reaction to the epoxide, considering both catalytic activity and separation feasibility. Catalytic essays are then performed to identify the optimal operating pressure for the reactor, revealing that 20 bar minimizes energy consumption. Afterwards, the kinetic study allows designing the reactor, which was conveniently sized to assess reliable TEA and LCA. The results indicate that increasing the residence time leads to higher conversion rates, requiring a larger reactor but reducing the final costs of the process. Achieved key performance indicators (KPIs) are capital and operating expenses (CAPEX and OPEX) of 161 $ and 153$ per ton CO 2 converted, respectively. In terms of Global Warming Potential (GWP), the proposed process emits approximately 0.34 kg of CO 2 per kg of converted CO 2 when considering only utility-related emissions, thus supporting the goal of emission reduction. • Kinetic model for hexylene carbonate production using high performance [bmim][I]. • Experimental and process evaluation of reactor pressure and size on energy and costs. • First work rigorously addressing CAPEX and OPEX in a sequential CCU process. • Costs distribution for OPEX and CAPEX, highlighting also IL impact.