Résumé | The performance of two antifreeze proteins (AFPs), type I and III (AFP I and III), as kinetic natural gas hydrate inhibitors in saline solutions was evaluated using a high pressure micro differential scanning calorimeter and a high pressure apparatus consisting of two crystallizers. Although AFP I and III were found to prolong crystallization time and reduce initial gas hydrate growth in saline solutions, the growth rate increased when hydrate started to form in the gas phase. Circular dichroism experiments suggested that the saline solution did not perturb AFP I and III structures. However, in the presence of saline, the inhibitory activity of AFP I to prolong induction time decreased while AFP III was more active. As a consequence, we propose that a decrease in hydrophobic forces and the neutralization of ion charges could explain AFP adsorption to the surface of hydrate crystals. Once the hydrate formed, melting was delayed, and consequently hydrate decomposition took longer in the presence of AFPs. We suggest conditions whereby the properties of AFPs could be harnessed for petrochemical recovery and transport. © 2014 American Chemical Society. |
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