AquaCCUS – A Cost-Efficient Gas Separation and CO2 Capture Solution

Gas separation and emission reduction in offshore environments is challenging due to limited platform space, marine conditions, safety considerations, and limited access to renewable power. A cost-effective solution is presented using an aqueous gas separation system, termed AquaCCUS, in two offshore case studies: 1) CO2 Capture from Combined Cycle Gas Turbines (CCGT) with optional Carbonated Water (CW) Injection (in 2 examples, Brazil and Norway), and 2) Separation of CO2 in Reservoir Production, improving the value of acid/sour reserves. The Value Chain is demonstrated using data from the Brazilian offshore Santos Basin Tupi field and from the fields on the Norwegian Continental Shelf (NCS). AquaCCUS consist of a whole CCUS value chain and uses a patented Pi-CO2 capture system ac the core technology to capture CO2 in water, an simple and elegant solution that has been vetted in a decade of prior work with research institutes in 6 countries. and more than 15 companies in diverse industry sectors. This prior work has vetted and de-risked the technology with independent reviews, thermodynamic models, industry-specific designs, technical economic assessments (TEAs), prototype optimization, and lab pilot demonstrations, reported by Boyd et al. 2018; O’Neil 2019; Guo et al. 2022,2025 [7,21,14,15]. Two models simulate flow and efficiencies: a proprietary Mass-Transfer model and The Aspen HYSYS® models, both validated against empirical and experimental data. The results provide operating conditions, component specifications, and total costs for the Case Studies. AquaCCUS/Pi-CO2 capture is unique in using the hydrostatic pressure gradient formed by a tall column of water (subsurface onshore or offshore) to preferentially dissolve and separate acid and non-acid gases. In a non-complex design, the separation column (a multistage cascading absorber) is simply suspended in water, from an offshore platform, or if on-land, in a sealed water-filled subsurface shaft, deep lake, or fjord. For non-pressurized sources, the system integrates a novel method of hydro-compression that significantly reduces power demands and total costs. The captured CO2 can be brought to the surface, dewatered and compressed for pipeline transport, or uniquely, can be kept in a dissolved state and directly injected as carbonated water (CW) for permanent storage, with or without EOR. The use of water as a solvent offers significant advantages in offshore capture. Advances in CO2/Water Alternating Gas (WAG) Enhanced Oil Recovery (EOR) in Brazilian Pre-Salt oil fields was the original motivation for evaluating the AquaCCUS offshore value chain. Similarly, most of the platforms on the NCS use water injection and WAG.to enhance recovery. The results for Case 1 (capture from CCGTs in offshore production) suggest that combining existing platform water injection systems with AquaCCUS capture from gas turbines is a cost-effective solution that significantly reduces emissions, risks, and potential ecosystem impacts. Case 2 explores using AquaCCUS to separate CO2 (or H2S) from oil/gas reserves in natural gas production in the Tupi field, (in replacement of membrane capture). In this case, the source gas is already pressurized in the reservoir, offering even lower costs, while also lowering offshore risks and impacts. Both cases demonstrate high value in offshore capture and identify a Field Pilot as the next step in development. The Case Studies demonstrate the value of an AquaCCUS system in reducing costs and risks in offshore gas separation and emission reduction.