Reaction rate constant of CO₂–Tetra‐n‐butylammounium bromide semi‐clathrate formation

Abstract

Semi-clathrate growth experiments were performed using a carbon dioxide-water-tetra-n-butyl ammonium bromide system. Experiments were conducted in a semi-batch stirred tank crystallizer at temperatures of 287, 288, and 289 K with a 3-K subcooling at each temperature. Gas consumption, temperature, hydrate former mole fraction, and particle size were measured throughout growth. Significant differences in gas consumption and heat effects were observed with these systems compared with pure clathrate systems. A kinetic growth model was applied to estimate the intrinsic rate constant. Rate constants did not show a clear trend with temperature at the conditions studied. Intrinsic reaction rate constant values ranged from 7.6 Â 10 À6 m/s to 13.8 Â 10 À6 m/s.

Kinetics of carbon dioxide gas hydrates with tetrabutylammonium bromide and functionalized multi-walled carbon nanotubes

“…In these experiments, the gas consumption profile did not change for the first 120 seconds after nucleation. This trend is consistent with results reported by Verrett et al [23].…”

“…In this run, the gas hydrates nucleated at 3294 seconds, designated by the leftmost vertical green dotted line. As discussed in Verrett et al [23], there is a slight time delay at nucleation before gas starts being consumed again. This is because the oversaturated liquid has enough carbon dioxide dissolved to form and grow the hydrates for a short period of time without the need for more gas.…”

“…In another report, it was shown that a 40-45 wt % TBAB solution may be a promising cold storage material for air conditioning systems due to its high phase change temperature and its improved hydrate conversion [22]. Recently, the kinetic behaviour of TBAB and carbon dioxide gas hydrates was thoroughly investigated at temperatures ranging from 13.85 °C to 15.85 °C [23]. Other semi-clathrate forming salts, such as tetrabutylammonium nitrate (TBANO 3 ) and tetrabutylammonium fluoride (TBAF) have also been studied and proven feasible for use in hydrate based gas separation applications [24][25][26].…”

Modeling of hydrate-based CO2 capture with nucleation stage and induction time prediction capability

“…Several studies have investigated the CO hydration reaction rate during gas hydrate formation (Bergeron and Servio, 2008;Chun and Lee, 1996;Malegaonkar et al, 1997;Ou et al, 2016;Verrett and Servio, 2016). A sensitivity analysis of the competing reactions using the rates constants and was carried out to investigate the species distribution and steps/phases k 2 k 3 lifetime and induction time.…”

Investigation of kinetics of tetrabutylammonium chloride (TBAC) + CH4 semiclathrate hydrate formation

“…In 2014, Zhang et al 14 studied the formation kinetics of (TBAB + CO 2 ) SCHs at mass fraction ¼ (0.05 and 0.10), and the results revealed that the moles of formed SCHs and the formation rates both increased with the increase of subcooling degree. In 2016, Verrent et al 37 investigated the hydrate growth of (TBAB + CO 2 ) at 0.40 salt mass fraction. However, as compared to TBAB, TBAC was reported to give a higher pressure reduction for N 2 /CO 2 hydrate formation and a similar pressure reduction for CH 4 hydrate formation.…”