Enhanced Selectivity of the Separation of CO₂from N₂during Crystallization of Semi-Clathrates from Quaternary Ammonium Solutions

Abstract

Re´sume´-Ame´lioration de la se´lectivite´du captage du CO 2 dans les semi-clathrates hydrates en utilisant les ammoniums quaternaires comme promoteurs thermodynamiques -La re´duction des e´missions de CO 2 est tre`s probablement l'un des enjeux importants de ce sie`cle. La capture puis le stockage ge´ologique de ce gaz, a`partir de sources industrielles ponctuelles et massives, est une voie d'importance. L'une des voies technologiques consiste a`utiliser les clathrates hydrates, ou semi-clathrates hydrates, qui ne´cessitent de pressuriser le gaz en amont du proce´de´. Sous pression, l'eau et les gaz forment un solide qui encapsule pre´fe´rentiellement le CO 2 , puis le gaz peut-eˆtre ensuite re´cupe´re´sous pression apre`s la dissociation du solide. L'abaissement de la pression ope´ratoire est un objectif en soi afin de faire baisser les couˆts ope´ratoires. Cet abaissement peut eˆtre obtenu par l'utilisation de promoteurs thermodynamiques, dont les sels d'ammonium quaternaires constituent une famille inte´ressante puisqu'ils forment des solides naturellement anti-agglome´rants, et plus facilement manipulables. Dans ce travail, nous pre´sentons de nouveaux re´sultats expe´rimentaux sur les e´quilibres des semi-clathrates de (CO 2 , N 2 ) en pre´sence de Tetra-n-Butyl Ammonium Bromide (TBAB). Nous donnons des mesures expe´rimentales de pression et tempe´rature en fonction de la concentration en TBAB. La pression ope´ratoire peut eˆtre abaisse´e jusqu'a`la pression atmosphe´rique. Nous donnons aussi une information supple´mentaire portant sur la composition de l'hydrate. Nous observons que la se´lectivite´du CO 2 dans les semi-clathrates hydrates est bien meilleure que pour les clathrates hydrates traditionnels, sans promoteur thermodynamique.Abstract -Enhanced Selectivity of the Separation of CO 2 from N 2 during Crystallization of SemiClathrates from Quaternary Ammonium Solutions -CO 2 mitigation is crucial environmental problem and a societal challenge for this century. CO 2 capture and sequestration is a route to solve a part of the problem, especially for the industries in which the gases to be treated are well localized. CO 2 capture by using hydrate is a process in which the cost of the separation is due to compression of gases to reach the gas hydrate formation conditions. Under pressure, the water and gas form a solid that encapsulates preferentially CO 2 . The gas hydrate formation requires high pressures and low

Cyclopentane hydrates – A candidate for desalination?

“…Depending on size and nature of the guest molecules, water molecules can form different kind of cages that combine to form a crystal lattice according to three well-known 0 500 1000 1500 2000 2500 1975 1977 1979 1981 1983 1985 1987 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 2012 2014 2016 2018 Publications Year structures: I, II, and H. Since water is usually present in the oil and gas flowlines, gas hydrates are well known to plug pipelines [14]. Besides, several potential applications of clathrate hydrates have been investigated, such as gas storage [15][16][17][18], carbon dioxide capture [19,20], gas transportation [15,21], gas separation [22,23], air-conditioning [24][25][26], and of course seawater desalination [11,13,27,28].…”

“…Note that CP act as a hydrate promoter for other applications, such as carbon capture, as described in detail by Herri et al [22], or Zheng et al [47]. It is a co-guest used to milder hydrate formation conditions when combined to other molecules such as N 2 [40,[48][49][50], C 3 H 8 [51], CO 2 [48,49,[52][53][54], CH 4 [40,49,55,56], or H 2 S [56].…”

Experimental measurement and thermodynamic modeling of cyclopentane hydrates with NaCl, KCl, CaCl2, or NaCl‐KCl present

“…Indeed, their formation is a common nuisance in the oil and gas industry . Nevertheless, there are many new and potentially profitable applications such as natural gas storage, hydrogen storage, carbon dioxide capture, gas separation, and air‐conditioning, and cold thermal energy …”

Designing the structure and relevant properties of semiclathrate hydrates by partly asymmetric alkylammonium salts

“…[15][16][17][18][19] Therefore, CO 2 capture and gas separation techniques based on semiclathrate hydrates from various industrial gas sources have been proposed. [20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35] Alkylammonium salts such as tetra-n-butylammonium (denoted as N 4444 or TBA) bromide (denoted as N 4444 Br or TBAB) are the most widely used ionic guest substances, which can form highly stable semiclathrate hydrates. As investigated in the field of ionic liquids and metal-organic frameworks, there are numerous species of alkylammonium compounds.…”