In situ monitoring of additives during CO2 gas hydrate formation

Abstract

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.