Intensified Carbon Dioxide Hydrate Formation Kinetics in a Simulated Subsea Sediment: Application in Carbon Capture and Sequestration

Abstract

To achieve the United Nations Climate Change Conference (COP-26) targets of net zero carbon emissions, hydrate-based carbon dioxide (CO 2 ) capture and sequestration (CCS) can be considered one of the potential sustainable technologies. However, the sluggish kinetics of CO 2 hydrate formation in the saline subsea environment and the nonecofriendly nature of the existing additives (kinetic promoters) are the major challenges. Therefore, to intensify the kinetics, the performance of the biocompatible hydrophobic amino acid Lleucine for CO 2 hydrate formation/dissociation was evaluated using the simulated subsea sediment of silica sand. Experiments were performed in saline (3.0 wt % NaCl) and nonsaline environments with L-leucine (0.1−1.0 wt %) at 3.2 ± 0.2 MPa pressure and 274.5 ± 0.2 K temperature. With the addition of 0.5 wt % L-leucine to freshwater, water-to-hydrate conversion of 73.01 ± 4.96% (44.08 ± 2.95% gas-to-hydrate conversion) was achieved with a rate of gas uptake of 4.25 ± 0.39 mmol/min, which is ∼10 times higher compared to the baseline (no promoter). Though salinity significantly reduced the hydrate formation kinetics, the addition of 1.0 wt % L-leucine intensified the rate of CO 2 uptake to 2.32 ± 0.319 mmol/min from 0.55 ± 0.033 mmol/min in saline water baseline. The enhanced kinetics reported in this work highlights the potential of engaging L-leucine in the hydrate-based CCS approach.

Coupling Amino Acid with THF for the Synergistic Promotion of CO2 Hydrate Micro Kinetics: Implication for Hydrate-Based CO2 Sequestration

“…Cai et al 38 showed that L-Met possessed an excellent promotion effect on the formation of CO 2 hydrate, with CO 2 gas uptake reaching up to 0.145 mol CO 2 /mol H 2 O in 1000 min at the concentration of 0.1 wt %. Gautam et al 39 found that adding 0.5 wt %L-leucine to freshwater resulted in CO 2 gas uptake of 0.10 mol CO 2 /mol H 2 O, which was four times higher than the system without a promoter. In addition, L-isoleucine and L-tryptophan have also been proved to be kinetic promoters for improving CO 2 hydrate kinetics.…”

“…Cai et al showed that l -Met possessed an excellent promotion effect on the formation of CO 2 hydrate, with CO 2 gas uptake reaching up to 0.145 mol CO 2 /mol H 2 O in 1000 min at the concentration of 0.1 wt %. Gautam et al found that adding 0.5 wt % l -leucine to freshwater resulted in CO 2 gas uptake of 0.10 mol CO 2 /mol H 2 O, which was four times higher than the system without a promoter. In addition, l -isoleucine and l -tryptophan have also been proved to be kinetic promoters for improving CO 2 hydrate kinetics. − Thus, in our study, we mainly focus on how low-dose THF (less than 1.0 mol %) can improve the kinetics of CO 2 hydrate formation and aim to examine if there is a synergistic effect when low-dose THF is coupled with a type of amino acid, l -Met, as a KHP for CO 2 hydrate.…”

Review on Cooperative Effect of Compound Additives on CO2 Hydrate Formation: Recent Advances and Future Directions

“…112−116 However, current research has shown that only some amino acids (e.g., L-methionine, L-tryptophan, and L-leucine) can considerably improve the formation kinetics of the CO 2 hydrate. 117,118 Presently, why only some hydrophobic amino acids can effectively promote the formation of the CO 2 hydrate remains unclear.…”

“…Notably, among the different amino acids, only the L-methionine, L-tryptophan, and Lleucine can promote the CO 2 hydrate formation. 117,118 Although the reason for this phenomenon remains unclear, the promotion mechanism must be elucidated because it is conducive to finding more effective promoters. Table 7 summarizes the experimental conditions of these studies.…”

Elucidating the Impact of Thermodynamic Hydrate Inhibitors and Kinetic Hydrate Inhibitors on a Complex System of Natural Gas Hydrates: Application in Flow Assurance

“…The moles/rate calculations during hydrate formation were similar to our previous studies. 29,31 The gas uptake or mole of gas consumed during the hydrate growth phase was calculated using eq 1 and presented as a mole of gas consumed per mole of water in all the figures below.…”