Kinetics of(TBAF+CO2)semi-clathrate hydrate formation in the presence and absence of SDS

In this communication, the impacts of adding SDS （sodium dodecyl sulfate）, TBAF （tetra-n-butylammonlum tluorloe） ano the mixture of SDS ＋ TBAF on the main kinetic parameters of CO2 hydrate formation （induction time, the quantity and rate of gas uptake, and storage capacity） were investigated. The tests were performed under stirring conditions at T = 5 ℃ and P = 3.8 MPa in a 169 cm3 batch reactor. The results show that adding SDS with a concentration of 400 ppm, TBAF with a concentration of l-5 wt%, and the mixture of SDS ＋ TBAF, would increase the storage capacity of CO2 hydrate and the quantity of gas uptake, and decrease the induction time of hydrate formation process. The addition of 5 wt% of TBAF and 400 ppm of SDS would increase the CO2 hydrate storage capacity by 86.1% and 81.6%, respectively, compared to pure water. Investigation of the impact of SDS, TBAF and their mixture on the rate of gas uptake indicates that the mixture of SDS ＋ TBAF does not have a significant effect on the rate of gas uptake during hydrate formation process.

Semi-clathrate hydrate based carbon dioxide capture and separation techniques

CO_(2)is considered as the main contributor to global warming,and hydrate enclathration is an efficient way for carbon capture and separation(CCS).Semi-clathrate hydrate(SCH)is a type of clathrate hydrate capable of encaging CO_(2)molecules under mild temperature and pressure conditions.SCH has numerous unique advantages,including high thermal stability,selective absorption of gas molecules with proper size and recyclable,making it a promising candidate for CCS.While SCH based CCS technology is in the developing stage and great efforts have to be conducted to improve the performance that is determined by their thermodynamical and structural properties.This review summarizes and compares the thermodynamic and structural properties of SCH and quaternary salt hydrates with gas mixtures to be captured and separated.Based on the description of the physical properties of SCH and hydrate of quaternary salts with gas mixture,the CO_(2)capture and separation from fuel gas,flue gas and biogas with SCH are reviewed.The review focuses on the use of tetra-nbutyl ammonium halide and tetra-n-butyl phosphonium halide,which are the current application hotspots.This review aims to provide guidance for the future applications of SCH.