Experiment Investigation of SiO2 Containing Amino Groups as a Kinetic Promoter for CO2 Hydrates

To diminish the greenhouse effect by reducing CO2 emission into the air based on a capture and sequestration method through hydrates, the thermodynamic and kinetic effects of additives on CO2 hydrate formation under 1.5 MPa in the presence of 5, 6, 8, 10, and 20 wt % RNS-A (reactive SiO2 containing amino groups) were studied, and the stirrer speed was set to 800 rpm. This paper calculated the gas consumption and explained the possible mechanisms of RNS-A on CO2 hydrates. The results showed that RNS-A was a kinetic additive instead of a thermodynamic one. It was found that 5-10 wt % RNS-A all shortened the induction time of hydrates, but only 5 and 6 wt % RNS-A increased the gas consumption of CO2 hydrates. Although we observed the shortest induction time at a 10 wt % RNS-A system, the lowest gas consumption indicated its weak CO2 capture and storage ability. In addition, when the concentration was 6 wt %, RNS-A had the highest gas consumption and its reaction time was relatively short. Considering the induction time and gas consumption, 6 wt % RNS-A was the optimal RNS-A concentration for CO2 capture and sequestration, which was the most suitable for practical applications.