In situ monitoring of additives during CO₂ gas hydrate formation

Research activities on the reduction of carbon dioxide emissions via effective carbon capture and storage (CCS) techniques are steadily increasing with the concept of storing CO₂ as hydrates among the most prominently discussed strategies. The present study utilizes mid-infrared (MIR) fiber-optic evanescent field sensing techniques as a promising in situ monitoring tool for investigation of molecular changes occurring during CO₂ hydrate formation. The identification and evaluation of characteristic IR absorption features associated with additive molecules (here, THF and SDS) and their changes during hydrate formation were pronounced via studies in D₂O next to H₂O as the hydrate-forming matrix. By correlating IR-spectroscopic data with continuously recorded pressure and temperature traces, hypotheses on the involvement and promoting effect of such additives during carbon dioxide gas hydrate formation were experimentally consolidated.