Enhanced Hydrate-Based Geological CO₂ Capture and Sequestration as a Mitigation Strategy to Address Climate Change

• Main Authors: Jyoti Shanker Pandey, Yousef Jouljamal Daas, Adam Paul Karcz, Nicolas von Solms
• Format: Article
• Language: English
• Published: MDPI AG 2020-10-01
• Series: Energies
• Subjects: climate change; CO2 capture and sequestration; amino acids; formation kinetics; permafrost and marine sands
• Online Access: https://www.mdpi.com/1996-1073/13/21/5661

Geological sequestration of CO₂-rich gas as a CO₂ capture and storage technique has a lower technical and cost barrier compared to industrial scale-up. In this study, we have proposed CO₂ capture and storage via hydrate in geological formation within the hydrate stability zone as a novel technique to contribute to global warming mitigation strategies, including carbon capture, utilization, and storage (CCUS) and to prevent vast methane release into the atmosphere caused by hydrate melting. We have attempted to enhance total gas uptake and CO₂ capture efficiency in hydrate in the presence of kinetic promoters while using diluted CO₂ gas (CO₂-N₂ mixture). Experiments are performed using unfrozen sands within hydrate stability zone condition and in the presence of low dosage surfactant and amino acids. Hydrate formation parameters, including sub-cooling temperature, induction time, total gas uptake, and split fraction, are calculated during the single-step formation and dissociation process. The effect of sands with varying particle sizes (160–630 µm, 1400–5000 µm), low dosage promoter (500–3000 ppm) and CO₂ concentration in feed gas (20–30 mol%) on formation kinetic parameters was investigated. Enhanced formation kinetics are observed in the presence of surfactant (1000–3000 ppm) and hydrophobic amino acids (3000 ppm) at 120 bar and 1 ℃ experimental conditions. We report induction time in the range of 7–170 min and CO₂ split fraction (0.60–0.90) in hydrate for 120 bar initial injection pressure. CO₂ split fraction can be enhanced by reducing sand particle size or increasing the CO₂ mol% in incoming feed gas at given injection pressure. This study also reports that formation kinetics in a porous medium are influenced by hydrate morphology. Hydrate morphology influences gas and water migration within sediments and controls pore space or particle surface correlation with the formation kinetics within coarse sediments. This investigation demonstrates the potential application of bio-friendly amino acids as promoters to enhance CO₂ capture and storage within hydrate. Sufficient contact time at gas-liquid interface and higher CO₂ separation efficiency is recorded in the presence of amino acids. The findings of this study could be useful in exploring the promoter-driven pore habitat of CO₂-rich hydrates in sediments to address climate change.