Effects of Tween 80 on clathrate and semiclathrate CO2 hydrate formation kinetics for carbon capture from CO2-rich gas mixtures

Abstract

In this study, Tween 80 was chosen as a kinetic promoter to study the effect of non-ionic surfactant on CO2 hydrate formation kinetics. The experiments were carried out in a thermostatic reactor using CO2-rich gas mixtures with Tween 80 (0–3000 ppm) in both clathrate hydrates and tetra-n-butyl ammonium bromide (TBAB) semiclathrate hydrates. Analysis of variance (ANOVA) was used to analyze the difference among experimental results, and a decision box was proposed to evaluate the performance of systems studied. The apparent improvement in the induction time, gas uptake yield, and gas separation performance were observed in 1000-ppm or 2000-ppm Tween 80 in semiclathrate hydrates. Increased pressure further improved the kinetic promotion effect of Tween 80. However, a higher concentration of 3000-ppm Tween 80 was found to result in an inhibition effect on CO2 uptake yield in semiclathrate hydrates, although the induction time remained short. Compared with common anionic and cationic surfactants, 2000-ppm Tween 80 showed the best CO2 separation performance from gas mixtures in semiclathrate hydrates. No inhibition effect was observed in clathrate hydrates with studied concentrations of Tween 80.

Keywords

• Semiclathrate hydrates
• Carbon capture
• Formation kinetics
• Tetra-n-butyl ammonium bromide
• Tween 80