Use of the thermodynamic promoter TBAB in synergy with kinetic promoters to improve the separation of CO2 + CH4 gas mixture by clathrate hydrate formation
Abstract
Gas separation by clathrate hydrate formation (GSHF) process is a new technique that could
be used to upgrade biogas. In this process the CO2 is supposed to be captured into the solid
phase while vapor will the enriched in CH4. The efficiency of such all process can be
improved by using thermodynamic promoters in synergy with kinetic promoters. In this work, we performed a CO2 + CH4 gas separation study using the thermodynamic promoter tetrabutylammonium bromide (TBAB) and three kinetic promoters: sodium dodecyl sulfate (SDS), cetyl trimethyl ammonium bromide (CTAB), and dodecyl trimethyl ammonium bromide (DTAB). Experiments were realized using an instrumented high pressure reactor coupled to a gas chromatography analyzer instrument that allowed to monitor in real-time the gas composition evolution during gas hydrate formation. An experimental protocol exploiting the memory effect of hydrate crystallization was applied. The synergy of TBAB with the kinetic promoters SDS, CTAB, and DTAB was evaluated in terms of induction time, crystal growth rate and CO2 capture rate.