Eliminating active CO2 concentration in Carbon Capture and Storage (CCUS): Molten carbonate decarbonization through an insulation/diffusion membrane

Abstract

Present industrial decarbonization technologies require an active CO₂-concentration system, often based on lime reaction or amine binding reactions, which is energy intensive and carries a high CO₂-footprint. Here instead, an effective process without active CO₂ concentration is demonstrated in a new process-termed IC2CNT (Insulation-diffusion facilitated CO₂ to Carbon Nanomaterial Technology) decarbonization process. Molten carbonates such as Li₂CO₃ (mp 723 ​°C) are highly insoluble to industrial feed gas principal components (N₂, O₂, and H₂O). However, CO₂ can readily dissolve and react in molten carbonates. We have recently characterized high CO₂ diffusion rates through porous aluminosilicate and calcium-magnesium silicate thermal insulations. Here, the CO₂ in ambient feed gas passes through these membranes into molten Li₂CO₃. The membrane also concurrently insulates the feed gas from the hot molten carbonate chamber, obviating the need to heat the (non-CO₂) majority of the feed gas to high temperature. In this insulation facilitated decarbonization process CO₂ is split by electrolysis in the molten carbonate producing sequestered, high-purity carbon nanomaterials (such as CNTs) and O₂.