CO₂ Hydrate Formation Promoted by a Natural Amino Acid l‐Methionine for Possible Application to CO₂ Capture and Storage

Abstract

We demonstrate that l‐methionine, a natural amino acid, can be used to dramatically enhance CO2 uptake kinetics in the formation of CO2 hydrate without the use of energy‐intensive mixing technologies or environmentally harmful chemicals. To the best of our knowledge, l‐methionine is the most effective promoter to enhance CO2 hydrate formation (at a concentration of 0.2 wt %, the gravimetric capacity reached up to 356 mg g−1 in 1000 min, and t90 (the time to achieve 90 % of this capacity) was only 15 min). We also present a tentative explanation for the promotion mechanism of l‐methionine in the formation of CO2 hydrate from the point of view of structure–property relationship that will help search for more effective promoters. Our results may offer the possibility of practical application of hydrate‐based CO2 capture and storage technology.

Screening of Amino Acids and Surfactant as Hydrate Promoter for CO2 Capture from Flue Gas

“…Roosta et al [28] have demonstrated that the inhibition effect of uncharged amino acid tends to increase with the increasing length of side chains; therefore, L-methionine is expected to be better CO 2 hydrate promoter compared to L-valine due to lower hydrophobicity of the side chain. Cai et al [45] have tested CO 2 hydrate kinetics in the presence of L-methionine and found CO 2 hydrate formation kinetics and hydrate storage capacity to be dramatically improved. The effect of different concentrations on the formation rate and storage capacity was studied, and it was found that 0.2 wt% of L-methionine gave the optimal performance.…”

Clathrate Hydrates of Greenhouse Gases in the Presence of Natural Amino Acids: Storage, Transportation and Separation Applications

“…Further, Cai et al . reported 0.141 mol/molH 2 O (or 346 mg/g) CO 2 gas consumption in l-met (0.5 wt%) system 22 . The gas uptake values obtained in the present study are comparable to these results.…”

“…In practice, the hydrate dissociation is measured with slower temperature ramp, i.e., 0.5 to 1.0 K/h, to determine phase stability points. Faster temperature ramping, however, leads to measurable deviations from computed phase boundary curve 22 . The primary goal of this study is to probe gas hydrate formation ability in the presence AAs, and not on the dissociation behavior.…”

“…Recently the amino acids are being used to promote the hydrate formation rate, particularly under low concentrations 22 – 24 . The exact nature for its increased gas uptake ratio is still obscure.…”

“…In another study Cai et al . 22 , reported some amino acids, such as l-methionine, l-norvaline and l-norleucine have a large CO 2 gas storage potential in the form of hydrates and with faster gas uptake, even under non-stirred configuration. We also examined hydrate formation in CO 2 – H 2 O system, under similar experimental conditions, using some amino acids such as l-methionine, l-cystine and l-valine and found that the gas storage is high, whereas, it is less for l-phenylalanine and l-theornine containing systems 23 .…”