Hydrate formation rate and separation effect on the capture of CO2 from binary mixture via forming hydrate with 5 wt% tetra-n-butyl ammonium bromide （TBAB） solution were studied. The results showed that the inductio...Hydrate formation rate and separation effect on the capture of CO2 from binary mixture via forming hydrate with 5 wt% tetra-n-butyl ammonium bromide （TBAB） solution were studied. The results showed that the induction time was 5 min, and the hydrate formation process finished in 1 h at 4.5 ℃ and 4.01 MPa. The hydrate formation rate constant reached the maximum of 1.84× 10^-7 molZ/（s.J） with the feed pressure of 7.30 MPa. The CO2 recovery was about 45 % in the feed pressure range from 4.30 to 7.30 MPa. Under the feed pressure of 4.30 MPa, the maximum separation factor and CO2 concentration in hydrate phase were 7.3 and 38.2 mol%, respectively. The results demonstrated that TBAB accelerated hydrate formation and enriched CO2 in hydrate phase under the gentle condition.展开更多
Semiclathrate hydrates of tetra-n-butyl ammonium bromide （TBAB） offer potential solution for gas storage, transportation, separation of flue gases and CO2 sequestration. Models for phase equilibria for these systems...Semiclathrate hydrates of tetra-n-butyl ammonium bromide （TBAB） offer potential solution for gas storage, transportation, separation of flue gases and CO2 sequestration. Models for phase equilibria for these systems have not yet been developed in open literatures and thus require urgent attention. In this work, the first attempt has been made to model phase equilibria of semiclathrate hydrates of CH4, CO2 and N2 in aqueous solution of TBAB. A thermodynamic model for gas hydrate system as proposed by Chen and Guo has been extended for semiclathrate hydrates of gases in aqueous solution of TBAB. A correlation for the activity of water relating to the system temperature, concentration of TBAB in the system and the nature of guest gas molecule has been proposed. The model results have been validated against available experimental data on phase equilibria of semiclathrate hydrate systems of aqueous TBAB with different gases as guest molecule. The extended Chen and Guo＇s model is found to be suitable to explain the promotion effect of TBAB for the studied gaseous system such as, methane, carbon dioxide and nitrogen as a guest molecule. Additionally, a correlation for the increase in equilibrium formation temperature （hydrate promotion temperature, ATp） of semiclathrate hydrate system with respect to pure gas hydrate system has been developed and applied to semiclathrate hydrate of TBAB with several gases as guest molecules. The developed correlation is found to predict the promotion effect satisfactorily for the system studied.展开更多
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 e...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.展开更多
An efficient and greener protocol for the synthesis of poly functionalized pyridines using tetra-n-butyl ammonium fluoride （TBAF） in water is established. Remarkable advantages of the present synthetic strategy over...An efficient and greener protocol for the synthesis of poly functionalized pyridines using tetra-n-butyl ammonium fluoride （TBAF） in water is established. Remarkable advantages of the present synthetic strategy over the others are shorter reaction times, higher isolated yields, reuse of catalytic system, simple work-up procedure and more especially its applicability to heteryl and aliphatic aldehydes.展开更多
文摘Hydrate formation rate and separation effect on the capture of CO2 from binary mixture via forming hydrate with 5 wt% tetra-n-butyl ammonium bromide （TBAB） solution were studied. The results showed that the induction time was 5 min, and the hydrate formation process finished in 1 h at 4.5 ℃ and 4.01 MPa. The hydrate formation rate constant reached the maximum of 1.84× 10^-7 molZ/（s.J） with the feed pressure of 7.30 MPa. The CO2 recovery was about 45 % in the feed pressure range from 4.30 to 7.30 MPa. Under the feed pressure of 4.30 MPa, the maximum separation factor and CO2 concentration in hydrate phase were 7.3 and 38.2 mol%, respectively. The results demonstrated that TBAB accelerated hydrate formation and enriched CO2 in hydrate phase under the gentle condition.
基金supported by the the Industrial Consultancy and Sponsored Research (ICSR),Indian Institute of Technology Madras,Chennai (Project Number OEC/10 11/530/NFSC/JITE)the National Institute of Ocean Technology (NIOT),Chennai,India (Project Number OEC/10-11/105/NIOT/JITE)
文摘Semiclathrate hydrates of tetra-n-butyl ammonium bromide （TBAB） offer potential solution for gas storage, transportation, separation of flue gases and CO2 sequestration. Models for phase equilibria for these systems have not yet been developed in open literatures and thus require urgent attention. In this work, the first attempt has been made to model phase equilibria of semiclathrate hydrates of CH4, CO2 and N2 in aqueous solution of TBAB. A thermodynamic model for gas hydrate system as proposed by Chen and Guo has been extended for semiclathrate hydrates of gases in aqueous solution of TBAB. A correlation for the activity of water relating to the system temperature, concentration of TBAB in the system and the nature of guest gas molecule has been proposed. The model results have been validated against available experimental data on phase equilibria of semiclathrate hydrate systems of aqueous TBAB with different gases as guest molecule. The extended Chen and Guo＇s model is found to be suitable to explain the promotion effect of TBAB for the studied gaseous system such as, methane, carbon dioxide and nitrogen as a guest molecule. Additionally, a correlation for the increase in equilibrium formation temperature （hydrate promotion temperature, ATp） of semiclathrate hydrate system with respect to pure gas hydrate system has been developed and applied to semiclathrate hydrate of TBAB with several gases as guest molecules. The developed correlation is found to predict the promotion effect satisfactorily for the system studied.
基金funded by the financial support from the China Geological Survey(No.DD20230063)the Guangdong Major Project of Basic and Applied Basic Research(No.2020B0301030003).
文摘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.
文摘An efficient and greener protocol for the synthesis of poly functionalized pyridines using tetra-n-butyl ammonium fluoride （TBAF） in water is established. Remarkable advantages of the present synthetic strategy over the others are shorter reaction times, higher isolated yields, reuse of catalytic system, simple work-up procedure and more especially its applicability to heteryl and aliphatic aldehydes.
