Dual Function Materials for Direct Air Capture of CO2

Direct air capture (DAC) technologies are being developed for carbon dioxide removal (CDR) at scale to mitigate the climate impact of CO2. Current estimates for DAC suggest that it can cost between $300 - $1,500/tonne of CO2 captured. Besides CDR technologies using long-term CO2 storage, reactive DAC technologies can capture and directly convert the captured CO2 into value-added products. The proposed project is aimed at optimizing an existing dual function material (DFM) and the associated modular process design for directly capturing CO2 from air and converting into renewable natural gas (RNG) using renewable H2 to significantly lower the overall cost of DAC by selling RNG. To achieve this goal, we are proposing to further develop and optimize the support structure for the DFM that was developed during the SBIR Phases I and II work for directly capturing CO2 from air and converting the captured CO2 into RNG. The DFM consists of structured supports which incorporate an adsorbent and a methanation catalyst for selective chemisorption of CO2, followed by sorbent regeneration through reversible desorption and catalytic conversion of the captured CO2 into methane using renewable H2. The material has shown high CO2 capacity (>6 wt%) under direct air capture of CO2 conditions and high CO2 conversion (>80%) in SBIR Phase II tests. In Phase IIA, we propose to further optimize the DFM support using structured carbons to achieve three main objectives: (1) improve CO2 conversion by using an electrically resistive material to achieve high heating rates, (2) reduce the energy requirement during the methanation step by reducing the support mass, (3) reduce DFM system manufacturing costs by using cheaper materials and fewer processing steps. We have designed the reactive DAC process in Phase II and evaluated the economic potential of this process. Preliminary techno-economic analysis shows that the DAC-DFM process is a promising technology with the potential to achieve a breakeven net cost of $0/tonne CO2 captured with an RNG selling price of $20/MMBTU not counting for any credits or incentives. The methane produced can be classified as RNG and should be eligible for tax credits/incentives, like low carbon fuel standards (LCFS) in California. This credit from the sales of RNG, in turn, would help lower the cost of DAC and allow deployment of the technology to further reduce the CAPEX and OPEX of the proposed DAC process. In SBIR Phase IIA of the proposed project, we will (1) further develop and optimize the DFM support structure by using novel structured carbon materials, (2) perform parametric testing using a bench-scale system to map the operating window of the DAC-DFM process and determine the long-term performance of the process and materials to make it ready for commercial deployment, (3) update and refine the process model and technical economic assessment (TEA) performed in SBIR Phase II to evaluate the commercial potential of the DAC-DFM process, and (4) develop a technology maturation and commercialization plan to determine key cost improvements, define key market sectors, and address the barriers to bring this technology to market.