Journées "Hydrates" 09 13 septembre 2019 - IFREMER 29280 PLOUZANE Pôle Numérique 305 Avenue Alexis de Rochon
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Journées Hydrates, Brest, 09‐13 septembre 2019
Journées “Hydrates”
09‐13 septembre 2019
IFREMER
Pôle Numérique
305 Avenue Alexis de Rochon
29280 PLOUZANE
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Journées Hydrates, Brest, 09‐13 septembre 2019
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Journées Hydrates, Brest, 09‐13 septembre 2019
WELCOME
We are pleased to welcome you for the 2nd meeting of the French research consortium
GdR2026 Hydrates at the University of Bordeaux. This event brings together leading
experimental, theoretical, and computational scientists from among the unusually broad
community of researchers interested in the various research areas of gas hydrates going
from chemical and energy engineering to geosciences and astrophysics through physical‐
chemistry and thermodynamics. The issues addressed during this meeting concern major
aspects of “hydrate sciences” such as hydrate/substrates interactions, thermodynamics,
formation kinetics, cage occupancy and as well as formation at extreme conditions.
The workshop is divided into two parts. The first part is dedicated to meetings of french
research consortiums working on a common project (ANR, EU, etc.) in closed session. The
second part is the general meeting, gathering about 60 participants. Its scientific program
contains about 31 presentations, including invited talks, oral contributions and poster
presentations.
Organizing committee
Livio Ruffine ‐ IFREMER, Brest
Hélène Ondréas ‐ IFREMER, Brest
Marie‐Odile Lamirault‐Gall ‐ IFREMER, Brest
Alison Chalm‐ IFREMER, Brest
Elisabeth Savoye ‐ IFREMER, Brest
Olivia Fandino‐Torres – IFREMER, Brest
Arnaud Desmedt, ISM CNRS ‐ Univ. Bordeaux
Karine Ndiaye, ISM CNRS ‐ Univ. Bordeaux
Audrey Bourgeois, ISM CNRS ‐ Univ. Bordeaux
Daniel Broseta – LFC‐R UMR 5150 CNRS, Total, Univ. Pau
Scientific Committee
Baptiste Bouillot ‐ LGF, UMR 5703 CNRS, Mines Saint‐Etienne
Daniel Broseta – LFC‐R UMR 5150 CNRS, Total, Univ. Pau
André Burnol – BRGM, Orléans
Bertrand Chazallon ‐ PhLAM UMR8523 CNRS Univ. Lille
Christophe Coquelet ‐ CTP, Mines ParisTech
Anthony Delahaye ‐ Division des Génie des Procédés et Froid, IRSTEA, Antony
Arnaud Desmedt ‐ ISM UMR5255 CNRS, Univ. Bordeaux
Christophe Dicharry ‐ LFC‐R UMR5150 CNRS, Total, Univ. Pau
Jean‐Michel Herri ‐ LGF, UMR 5703 CNRS, Mines Saint‐Etienne
Sylvain Picaud ‐ UTINAM UMR6213 CNRS, Univ. Franche‐Comté
Livio Ruffine ‐ IFREMER, Brest
Anne Sinquin ‐ IFPEN
Anh‐Minh Tang ‐ Laboratoire Navier UMR8205 CNRS, Ponts Paristech
Gabriel Tobie ‐ LPG UMR6112 CNRS, Univ. Nantes
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Journées Hydrates, Brest, 09‐13 septembre 2019
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Journées Hydrates, Brest, 09‐13 septembre 2019
CONTENT
WELCOME ........................................................................................................................... 3
DETAILED PROGRAM .......................................................................................................... 7
Lundi 9 septembre 2019 .................................................................................................................................................7
Mardi 10 septembre 2019 ..............................................................................................................................................9
Mercredi 11 septembre 2019 .................................................................................................................................... 11
Jeudi 12 septembre 2019............................................................................................................................................. 12
Vendredi 13 septembre 2019 .................................................................................................................................... 12
LIST OF PARTICIPANTS ...................................................................................................... 13
LIST OF ABSTRACTS ........................................................................................................... 15
Gas‐hydrate Pockmarks in deep water Nigeria: formation, evolution and related hazards 17
Guest Trapping and Selectivity within mixed Clathrate Hydrates: a Grand Canonical Monte
Carlo Study coupled with thermodynamic modelling ........................................................ 18
How different formation pathways impact the structure and separation efficiency in CO2‐
N2 gas mixtures using TBAB Semi‐clathrate Hydrates ........................................................ 19
Cascades of hydrate filaments promoted by a porous substrate, activated charcoal ........ 24
Mechanical homogenization of gas hydrate bearing soils ................................................. 27
Clathrate hydrate on planet Mars: at present time and in the past ................................... 31
Clathrate hydrates in the icy worlds of the Solar system ................................................... 32
Stability of mixed CH4‐CO2‐N2 hydrates and mass transfer during gas exchange ............... 33
Investigation of the exchange kinetic between methane and carbon dioxide in gas
hydrates: application to CO2 capture from flue gas analogs .............................................. 37
Gestion de la vapeur dans les boucles de refroidissement secondaire à hydrates de gaz .. 38
Flow loop experiments to study gas hydrate formation in gas‐water‐oil systems ............. 39
Modification of formation kinetics and of gas selectivity in “artificial” sedimentary gas
hydrates thanks to silica nano/micro‐beads. .................................................................... 40
Elastic parameters of hydrate‐bearing sands using DEM ................................................... 42
LIST OF POSTERS ............................................................................................................... 45
Quantitative study of CO2‐CH4 and N2‐CH4 mixed clathrate hydrates using gas
chromatography, Raman and IR reflectance spectroscopy: Application to icy moons ....... 47
NOTES ............................................................................................................................... 55
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Journées Hydrates, Brest, 09‐13 septembre 2019
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Journées Hydrates, Brest, 09‐13 septembre 2019
DETAILED PROGRAM
Lundi 9 septembre 2019
09:00 – 12:00 Réunions de projets
12:00 – 13:30 : Pause déjeuner
13:30 – 13:45 Accueil des participants et introduction
13:45 – 14:30 Plénière : N. Sultan “Gas hydrates pockmarks in deep water Nigeria:
formation, evolution and related hazards”
14:30 – 15h50 : Session 1 : Etudes fondamentales des hydrates de gaz : de l’échelle
moléculaire aux propriétés macroscopiques
14:30 Rodriguez et al.: How different formation pathways impact the structure and
separation efficiency in CO2‐N2 gas mixtures using TBAB Semi‐clathrate
Hydrates
14:50 Petuya et al.: Structural stability of CO clathrate hydrates using DFT
calculations
15:10 Chabab et al.: Thermodynamic study of the phase equilibria in the gas‐water‐
(NaCl) systems using electrolyte CPA EoS
15:30 – 16:00 : Pause café
16:00 – 17h20 : Session 2 : Etudes fondamentales des hydrates de gaz : de l’échelle
moléculaire aux propriétés macroscopiques
16:00 Patt et al.: Guest Trapping and Selectivity within mixed Clathrate Hydrates: a
Grand Canonical Monte Carlo Study coupled with thermodynamic modelling
16:20 Atig et al.: Contactless measurement of the mechanical properties of
methane hydrate at pore scales
16:40 Venet et al.: Cascades of hydrate filaments promoted by a porous substrate,
activated charcoal
17:00 Le et al.: Grain ‐scale morphology and distribution of methane hydrates
formed in sand sediment under excess gas conditions
7Journées Hydrates, Brest, 09‐13 septembre 2019
17:20 – 19h30 : Session 3 : Posters, échanges et buffet
Le Menn et al.: Quantitative study of CO2‐CH4 and N2‐CH4 mixed clathrate hydrates
using gas chromatography, Raman and IR reflectance spectroscopy: Application to icy
moons
Lemaire et al.: Influence of alkaline feldspars‐surrogates on the formation kinetic and
the selectivity of CO2‐N2 mixed hydrates: investigation by neutron scattering and
Raman spectroscopy
Espert et al.: Using quantum mechanics modeling for investigating the structural
properties of strong acid hydrates
Bazinet et al.: Study of Methane Hydrate Formation in Fontainebleau Sand Using X‐Ray
Computed Tomography: Methodological development
8Journées Hydrates, Brest, 09‐13 septembre 2019
Mardi 10 septembre 2019
08:30 – 09:00 : Accueil café
09:00 – 09:45 Plénière : P. Le Mélinaire « Desalination using clathrate hydrate »
09:45 – 12h15 : Session 4 : Hydrates naturels : Géosciences et Planétologie
09:45 Garziglia et al.: Insights into the characterization of gas hydrate‐bearing
sediments from in situ geotechnical and acoustic measurements
10:05 Alavoine et al.: Mechanical homogenization of gas hydrate bearing soils
10:25 Burnol et al.: GARAH: a GeoERA project addressing knowledge gaps to allow
gas hydrate assessment of the European continental margin
10:45 – 11:15 : Pause café
11:15 Lemaire et al.: Influence of alkaline feldspars‐surrogates on the formation
kinetic and the selectivity of CO2‐N2 mixed hydrates under astrophysical and
geophysical conditions
11:35 Schmidt et al.: Clathrate hydrate on planet Mars: at present time and in the
past
11:55 Tobie et al.: Clathrate hydrates in the icy worlds of the Solar system
12:15 – 14:00 : Pause déjeuner
14:00 – 14:45 : Plénière : P. Glennat « Hydrates & Production pétrolière »
14:45 – 17h00 : Session 5 : Procédés innovants
14:45 Legoix et al.: Stability of mixed CH4‐CO2‐N2 hydrates and mass transfer
during gas exchange
15:05 Martinez‐Escandell et al.: High‐performance of gas hydrates confined in
nanoporous solid for CH4 and CO2 storage
15:25 Le et al.: Investigation of the exchange kinetic between methane and carbon
dioxide in gas hydrates: application to CO2 capture from flue gas analogs
15:45 – 16:00 : Pause café
9Journées Hydrates, Brest, 09‐13 septembre 2019
16:00 Pons et al.: Gestion de la vapeur dans les boucles de refroidissement
secondaire à hydrates de gaz
16:20 Almeida et al.: Flow loop experiments to study gas hydrate formation in gas‐
water‐oil systems
16:40 Bouillot et al.: « TITRE A VENIR »
17:00 – 17:45 : Table ronde autour des problématiques industrielles
*******
19:00 – 23h00
Visite et Dîner de conférence
OCEANOPOLIS
Port de Plaisance du Moulin Blanc, Brest
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Mercredi 11 septembre 2019
08:30 – 09:00 : Accueil café
09:00 – 09:45 Plénière : H. Lu « TITRE A VENIR »
09:45 – 10h35 : Session 6 : Géosciences et Hydrates naturels
09:45 Métais et al.: Modification of formation kinetics and of gas selectivity in
“artificial” sedimentary gas hydrates thanks to silica nano/micro‐beads
10:05 Benmesbah et al.: Etude cinétique et thermodynamique des hydrates de gaz
en milieu poreux : applications aux hydrates sédimentaires et aux procédés de
stockage du froid
10:25 – 11:00 : Pause café
11:00 Theocharis et al.: Elastic parameters of hydrate‐bearing sands using DEM
11:20 Riboulot et al.: Freshwater lake to salt‐water sea causing widespread hydrate
dissociation in the Black Sea
11:40 – 12:00 Mot de clôture
12:00 : Fin des Journées Hydrates
12:30 – 16:00 Comité de Pilotage du GdR
11Journées Hydrates, Brest, 09‐13 septembre 2019
Jeudi 12 septembre 2019
09:00 – 12:00 : Accueil des élèves d’établissements secondaires du Finistère (Classes de
3ème et 1ère) : Ateliers scientifiques de découverte des géosciences
marines
12:00 – 14:00 : Pause déjeuner
14:00 – 17:00 : Accueil des élèves d’établissements secondaires du Finistère (Classes ULIS) :
Ateliers scientifiques de découverte des géosciences marines
Vendredi 13 septembre 2019
09:00 – 12:00 : Accueil des élèves d’établissements primaires (Classes de CM1 / CM2)
du Finistère : Ateliers scientifiques de découverte des géosciences
marines
12:00 : Fin des Journées « Scolaires »
12Journées Hydrates, Brest, 09‐13 septembre 2019
LIST OF PARTICIPANTS
ABADIE Emilie, Total E&P CSTJF – Pau, France (emilie.abadie@total.com)
ALAVOINE Axelle, École Nationale des Ponts et Chaussées – Marne‐la‐Vallée, France
(axelle.alavoine@enpc.fr)
ALMEIDA Vinicius, École des Mines de Saint‐Etienne – Saint‐Etienne, France (vinicius.de‐
almeida@emse.fr)
ATIG Dyhia, Univ. de Pau et des Pays de l'Adour – Pau, France (dyhia.atig@univ‐pau.fr)
BAZINET Laurène, Ifremer Brest – Plouzané, France (laurene.bazinet@yahoo.fr)
BENMESBAH Fatima Doria, Ifremer/IRSTEA–Plouzané, France (fatima.benmesbah@irstea.fr)
BOUILLOT Baptiste, École des Mines de Saint‐Etienne – Saint‐Etienne, France
(bouillot@emse.fr)
BOURGEOIS Lydie, ISM, Univ. de Bordeaux – Talence, France (lydie.bourgeois@u‐
bordeaux.fr)
BROSETA Daniel, LFC‐R, Univ. de Pau et des Pays de l'Adour – Pau, France
(daniel.broseta@univ‐pau.fr)
BURNOL André, BRGM – Orléans, France (a.burnol@brgm.fr)
CHABAB Salaheddine, Ecole des Mines de Paritech, Paris – France
(salaheddine.chabab@mines‐paritech.fr)
CHABOT Baptiste, École Nationale des Ponts et Chaussées – Marne‐la‐Vallée, France
(baptiste.chabot@enpc.fr)
CHAZALLON Bertrand, PhLAM, Univ. de Lille – Lille, France (bertrand.chazallon@univ‐lille.fr)
DE LAURE Emmanuel, École Nationale des Ponts et Chaussées – Marne‐la‐Vallée, France
(emmanuel.delaure@enpc.fr)
DELAHAYE Anthony, Irstea – Antony, France (anthony.delahaye@irstea.fr)
DESMEDT Arnaud, ISM, CNRS, Univ. Bordeaux – Talence, France (arnaud.desmedt@u‐
bordeaux.fr)
DICHARRY Christophe, LFCR, Univ. de Pau et des Pays de l'Adour – Pau, France
(christophe.dicharry@univ‐pau.fr)
DONVAL Jean‐Pierre, Ifremer Brest – Plouzané, France (jpdonval@ifremer.fr)
DUPRE Stéphanie, Ifremer Brest – Plouzané, France (stephanie.dupre@ifremer.fr)
ESPERT Sophie, DIPC, Univ. Politècnica de València – San Sebastian, Spain
(sophie.espert@etu.u‐bordeaux.fr)
ESTUBLIER Audrey , IFPEN – Paris, France (audrey.estublier@ifpen.fr)
FANDINO‐TORRES Olivia, Ifremer Brest – Plouzané, France (olivia.fandino.torres@fremer.fr)
GARZIGLIA Sébastien, Ifremer Brest – Plouzané, France (sebastien.garziglial@ifremer)
GELI Louis, Ifremer Brest – Plouzané, France (louis.geli@ifremer.fr)
GLENAT Philippe, Total E&P CSTJF – Pau, France France (philippe.glenat@total.com)
GUIMPIER Charlène, ISM, UMR 5255 CNRS, Univ. de Bordeaux – Talence, France
(charlene.guimpier@gmail.com)
LE MELINAIRE Pascal,……., (pln@b‐gh.com)
LE MENN Erwan, CNRS, Univ. de Nantes, France (erwan.lemenn@univ‐nantes.fr)
LE Quang‐Du, Univ. de Lille – Lille, France (quang‐du.le@outlook.fr)
LE Thi‐Xiu, École Nationale des Ponts et Chaussées – Marne‐la‐Vallée, France (thi‐
xiu.le@enpc.fr)
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LEGOIX, Ludovic, ISM, Univ. de Bordeaux & Univ. de Lille – Talence, France
(ludovic.legoix@univ‐lille.fr)
LEMAIRE Marine, École des Ponts ParisTech – Marne‐la‐Vallée, France
(marine.lemaire@enpc.fr)
LEMAIRE Morgane, ISM, Univ. de Bordeaux & Univ. de Lille – Talence, France
(morgane.lemaire@univ‐lille.fr)
LESAGE Elodie, Université Paris Sud – Orsay, France (frederic.schmidt@u‐psud.fr)
LU Hailong, , Université de Peking, – Pekin, Chine (hlu@pku.edu.cn)
MARTIN‐GONDRE Ludovic, Institut UTINAM / Groupe Space – Besançon France
(ludovic.martin@univ‐fcompte.fr)
MÉTAIS Cyrielle, ISM – Talence, France (cyrielle.metais@u‐bordeaux.fr)
ONDREAS Hélène, Ifremer Brest – Plouzané, France (helene.ondreas@ifremer.fr)
PATT Antoine, Laboratoire Interdisciplinaire Carnot de Bourgogne, Univ. Bourgogne
Franche‐Comté – Dijon, France (antoine.patt@u‐bourgogne.fr)
PICAUD Sylvain, Institut UTINAM, Univ. Franche Comte – Besançon, France
(sylvain.picaud@univ‐fcomte.fr)
PONS Michel, LIMSI, CNRS – Orsay, France (michel.pons@limsi.fr)
RIBOULOT Vincent, Ifremer Brest – Plouzané, France (riboulot@ifremer.fr)
RINNERT Emmanuel, Ifremer Brest – Plouzané, France (emmanuel.rinnert@ifremer.fr)
RODRIGUEZ MACHINE Carla Thais, Univ. de Lille, France (carla‐thais.rodriguez‐
machine@univ‐lille.fr)
ROUXEL Olivier, Ifremer Brest – Plouzané, France (orouxel@ifremer.fr)
RUFFINE Livio, Ifremer Brest – Plouzané, France (livio.ruffine@ifremer.fr)
SCALABRIN Carla, Ifremer Brest – Plouzané, France (carla.scalabrin@ifremer.fr)
SCHMIDT Frédéric, Université Paris Sud – Orsay, France – (frederic.schmidt@u‐psud.fr)
SILVESTRE‐ALBERO Joaquim, DIC, Univ. Alicante, Espagne (joaquim.silvestre@ua.es)
SIMON Jean‐Marc, ICB, Univ. de Bourgogne – Dijon, France (jmsimon@u‐bourgogne.fr)
SINQUIN Anne, IFPEN – Paris, France (anne.sinquin@ifpen.fr)
TALEB Farah, Ifremer Brest – Plouzané, France (farah‐taleb@hotmail.com)
TANG Anh Minh, École des Ponts ParisTech – Marne‐la‐Vallée, France (anh‐
minh.tang@enpc.fr)
THEOCHARIS Alexandros, École Nationale des Ponts et Chaussées – Marne‐la‐Vallée,
France (alexandros.theocharis@enpc.fr)
TOBIE Gabriel, Univ. de Nantes, France (Gabriel.Tobie@univ‐nantes.fr)
TOFFIN Laurent, Ifremer Brest – Plouzané, France (laurent.toffin@ifremer.fr)
TRINQUIER Anne, Ifremer Brest – Plouzané, France (anne.trinquier@ifremer.fr)
VENET Saphir, Université de Pau, France (saphir.venet@univ‐pau.fr)
14Journées Hydrates, Brest, 09‐13 septembre 2019
LIST OF ABSTRACTS
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Gas‐hydrate Pockmarks in deep water Nigeria: formation, evolution and
related hazards
Nabil Sultan*
*Ifremer, REM/GM/LAD, centre de Bretagne – nabil.sultan@ifremer.fr
The PREOWEI field is located in the Gulf of Guinea on the west coast of central Africa, south
of Nigeria and seaward of the modern Niger Delta. The PREOWEI field is characterized by the
presence of numerous circular to sub‐circular features of different shapes and sizes ranging
from a small ring depression surrounding an irregular floor to more typical pockmarks with
uniform depression. Acquired geophysical, geotechnical and sedimentological data show the
presence of a common internal architecture of the pockmark structures with inner
sediments rich in free gas and gas hydrates at shallow depths below the seafloor.
The aim of this talk is to summarize key findings undertaken during the last decade based on
different scientific ocean expeditions (NERIS 1&2, ERIG3D and Guineco‐MeBo). One of the
main finding concerns the importance of the hydrate dissolution and the evolution of the
hydrate‐pockmarks in the PREOWEI field (Figure 1). Moreover and due to the temperature
and pressure conditions of the PREOWEI site and the evidence of gas infiltration to the
shallow subsurface, free gas and gas hydrates are considered as a major hazard source.
Recent activities based on advanced numerical analyses have revealed the importance of
such hazard analysis for engineering subsea structure developments.
Figure 1. Sketch (a to f) of different steps in pockmark evolution during hydrate formation and dissolution.
17Journées Hydrates, Brest, 09‐13 septembre 2019
Guest Trapping and Selectivity within mixed Clathrate Hydrates: a Grand
Canonical Monte Carlo Study coupled with thermodynamic modelling
A. Patt1,2, J. M. Simon1, S. Picaud2, J. M. Salazar1
1 Laboratoire Interdisciplinaire Carnot de Bourgogne UMR 6303, 9 Av. Alain Savary, F‐
21078 Dijon, France
2 Institut UTINAM UMR 6213, 41 bis Av. de l’Observatoire, 25010
Besançon, France
Naturally occurring clathrate hydrates are at the heart of important environmental
concerns and are also subjects and/or means of study for astrophysicists (O. Mousis et al.;
Faraday Discuss. 147 (2010) 509). In situ conditions generally imply the presence of gas
mixtures in the hydrate forming system. The question of the competition between the
different molecular species in the process of clathration is then raised. Namely, the
selectivity is of interest to determine the most stable hydrates formed for given
compositions of gas mixtures. Among the clathrate hydrates of interest for extraterrestrial
environments are the N2, CO, and mixed N2‐CO hydrates (O. Mousis et al.; Astrophys. J.
691 (2009) 1780). They are involved in the models of the formation of planetesimals and
planetary atmospheres. A better understanding of the trapping capabilities of those
hydrates can help providing constraints on the chemical abundances of astrophysical
environments.
To that end, Grand Canonical Monte Carlo (GCMC) simulations constitute a useful and
effective tool to study those properties. In continuity with the adsorption analogy used to
model the equilibria of clathrate hydrates in the van der Waals – Platteeuw theory, GCMC
simulations can give the quantity of trapped, or adsorbed‐like, molecules in a clathrate
hydrate as a function of the chemical potential or applied pressure.
In the case of the mixed hydrate, we report a significant selectivity towards CO, in
agreement with experimental work (C. Pétuya, Ph.D. thesis, 2017), especially at low
temperatures. A two‐site adsorption behavior is evidenced for structure II hydrates
considered in this work: the small cages being more likely filled than the large ones.
Additionally, we show that the Ideal Adsorbed Solution Theory (IAST) gives results which
are in excellent agreement with those of our binary GCMC simulations (A. Patt et al.; J.
Phys. Chem. C 122 (2018) 18432). The influence of the gas phase composition on the
molecular selectivity is highlighted from both GCMC and IAST calculations, for which we
obtained qualitative agreements with experiments. After focusing on N2 and CO hydrates,
the study has been extended to other hydrates such as CO2, CH4, C2H6, and the
corresponding mixtures.
18Journées Hydrates, Brest, 09‐13 septembre 2019
How different formation pathways impact the structure and separation
efficiency in CO2‐N2 gas mixtures using TBAB Semi‐clathrate Hydrates
C.T. Rodriguez1, Q‐D. Le1, C. Focsa1, C. Pirim1, B. Chazallon1
1
Univ. Lille, CNRS, UMR 8523 – PhLAM ‐ Physique des Lasers Atomes et Molécules, CERLA –
Centre d’Etudes et de Recherche Lasers et Applications, F‐59000, Lille, France
Since several years a great effort has been devoted to reduce carbon dioxide (CO2) emissions
from anthropogenic activities (e.g. thermal power plants and steel making industries).
However, the also increasing energy demand worldwide makes the utilization of natural
gases and fossil fuel resources still essential for the process. These emissions are composed
mainly of CO2+N2 gas mixtures (with a CO2 concentration varying between 5 and 40%)
(D’alessandro, D. M.; Smit, B.; Long. J. R.; Angew. Chem. Int. (2010) 6058‐6082), causing a
negative impact in the composition of the atmosphere with the dramatic increase of
greenhouse gas concentrations. One way to overcome this problem at the short to mid‐term
is to apply CO2 Capture and Storage technology (CCS), for which continuous research efforts
are being deployed for the optimization of the process. In this context, the Hydrate‐Based
Separation Process (HSBP) represents a promising alternative to the existing technologies,
for which a number of drawbacks have been pointed out from the energetic and
environmental point of view. Specifically, in the hydrate technology, thermodynamic
promoters can be added to water in order to mitigate the operative conditions suitable for
an optimized process. Ionic salts (tetra‐n‐butyl ammonium bromide (TBAB)) dissolved in
water induce hydrates formation at specific p, T conditions and can remove CO2 from a gas
stream by guest‐gas encapsulation (Hashimoto, H.; Yamaguchi, T.; Ozeki, H.; Muromachi, S.;
Sci. Rep. (2017) 1‐10). Literature on TBAB semi‐clathrates has mostly focused on the study of
low concentrations of salt samples while studies for high concentrations (e.g. 35%) are
lacking. In order to diminish this major gap in the literature, this research examines the CO2
capture in a sample formed from (10%CO2+90%N2)‐35%TBAB‐H2O at a pressure of 3.7MPa in
a high‐pressure optical reactor with two distinct temperature protocols typically used in
hydrate processes. The objective is to investigate the influence of the formation protocol on
the structure and separation efficiency of the gas mixture at several temperatures on
approaching the dissociation temperature. Protocol 1 represents a multi‐cycling fast cooling
whereas protocol 2 represents a step‐by‐step slow cooling. The samples are analyzed by
micro‐Raman spectroscopy and optical macroscopy. A new experimental dissociation
temperature is found for our gas mixture at T=287.8K ± 0.3K. In terms of structure, the
encapsulation of the guest‐gases leads to a structural transition as previously observed
(Chazallon, B.; Ziskind, M.; Carpentier, Y.; Focsa, C.; J. Phys. Chem. 118 (2014) 13440‐13452).
Raman analysis reveals the influence of the structure on the selectivity by the measure of
the separation factor (S.F). Structure type A is shown to perform better for the separation
than structure type B or the polymorphic phase. Further, Protocol 2 shows a better
performance than protocol 1. Finally, S.F changes while approaching dissociation along with
an evolution of structure for the hydrate.
Ackowledgement: the authors thank the Région Hauts‐de‐France, the Ministère de
19Journées Hydrates, Brest, 09‐13 septembre 2019
l’Enseignement Supérieur et de la Recherche and the European Fund for Regional Economic
Development for their financial support (CPER CLIMIBIO).
20Journées Hydrates, Brest, 09‐13 septembre 2019
Structural stability of CO clathrate hydrates using DFT calculations
Claire Petuya1,2, Ludovic Martin‐Gondre3, Cyrielle Métais1,3,4 and Arnaud Desmedt1
1 Institut des Sciences Moléculaires (ISM) – Univ. Bordeaux, Talence, France
2 NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California
91109, USA
3 Institut UTINAM – Univ. Bourgogne Franche‐Compté, Besançon, France
4 Institut Laure Langevin (ILL), Grenoble, France
Contact : ludovic.martin@univ‐fcompte.fr
Carbon monoxide (CO) hydrate might be considered an important component of the carbon
cycle in the solar system since CO gas is one of the peredominant forms of carbon. Intriguing
fundamental properties have also been reported: the CO hydrate initially forms in the sl
structure (kinetically favored) and transforms into the sll structure (thermodynamically
stable) (Zhu, J., Du, S., Yu, X., Zhang, J., Xu, H., Vogel, S.C., Germann, T.C., Francisco, J.S.,
Izumi, F., Momma, K., Kawamura, Y., Jin? C. and Zhao, Y., Nat. Commun. 5, (2014) 4128).
Understanding and predicting the gas hydrate structural stability then become essential. The
aim of this work is thereby, to study the structural and energetic properties of the CO
hydrate using density functional theory (DFT) calculations. Performed on a complete unit cell
(sl and sll), DFT derived energy calculations lead indeed to the sll structure most
thermodynamically stable. In addition, increasing the CO content in the large cages has a
stabilizing effect on the sll structure, while it destabilizes the sl structure in agreement with
recent experimental results as shown in Fig. 1 (Petuya, C., Martin‐Gondre, L., Aurel, P.,
Damay, F. and Desmedt, A., J. Chem; Phys. 150 2019) 184705).
Figure 1: Calculated binding energy as a function of the large cage
occupancy
21Journées Hydrates, Brest, 09‐13 septembre 2019
Thermodynamic study of the phase equilibria in the gas‐water‐ (NaCl)
systems using electrolyte CPA EoS
S. Chabab1, A. Valtz1, A. Chapoy1, 2, C. Coquelet1
1 Mines ParisTech, PSL University, Centre of Thermodynamics of Processes, 35 rue Saint
Honoré, 77305 Fontainebleau Cedex, France
2 Institute of Petroleum Engineering, Heriot‐Watt University, Hydrates, Flow
Assurance & Phase Equilibria Research Group, Edinburgh EH14 4AS, Scotland,UK
Carbon dioxide emissions, which is the main greenhouse gas (in terms of quantity)
produced by human activity, are constantly increasing, mainly due to the exploitation and
use of fossil fuels. One of the possible solutions, that is of great interest to industrial actors
in the gas sector, is to capture, transport and store carbon dioxide in deep geological
formations (salt caverns, saline aquifers, etc.). In these underground geological
environments, the gas (CO2) is in contact with saline water, and depending on
pressure and temperature conditions, CO2 hydrates can be formed (especially in the case
of CO2 storage as hydrate in deep oceans). The flue gases from oxy‐fuel combustion are
mainly composed of CO2, O2 and steam. As part of the ANR FLUIDSTORY project, one
possibility is to store these CO2‐rich emissions in salt caverns and use them later for
methanation. During the transport or extraction of the CO2+O2 mixture from the
cavities, the rapid pressure drops can lead to condensation of water and then the
formation of hydrates, which in turns can leads to the clogging of pipelines.
The knowledge of phase equilibria as well as the hydrate stability zone of the CO2‐ O2‐
H2O and CO2‐H2O‐salt systems is of great importance. To achieve this, it is essential to
develop a thermodynamic model that is sufficiently accurate under the operating
conditions of transport and storage. This requires the availability of reliable experimental
data for this type of system. In this work, measurements of gas hydrate dissociation for
CO2 in the presence of NaCl and for the CO2/O2 mixture were carried out with an
experimental setup based on the isochoric method.
Fig. 1 : The e‐PR‐CPA model in terms of Helmholtz
energy.
A new electrolyte thermodynamic model (e‐PR‐CPA), which takes into account all
molecular and electrolyte interactions (Fig. 1), has been developed. This model has been
successfully applied to predict the solubility of CO2 and other gases (CH4, O2, H2, etc.) in
brine solution as well as the water content in a wide range of pressure, temperature and
salinity. The van der Waals and Platteeuw (vdWP) theory was combined with the e‐PR‐
CPA model to predict the hydrate forming conditions in the presence of electrolytes. The
developed model (e‐PR‐CPA + vdWP) captures very well the effect of electrolytes (NaCl) on
the CH4 (for validation) and CO2 hydrate stability zone. The model predictions are in good
agreement with the experimental measured and literature data.
22Journées Hydrates, Brest, 09‐13 septembre 2019
Contactless measurement of the mechanical properties of methane hydrate
at pore scales
D. Atig1, D. Broseta, J‐M. Pereira2, R. Brown3
1
CNRS/ TOTAL/ UNIV PAU & PAYS ADOUR E2S UPPA, Laboratoire des fluides complexes et de
leurs reservoirs, UMR5150, 64000 Pau, France.
2
Laboratoire Navier, UMR 8205, Ecole des Ponts Paris‐Tech, IFSTTAR, CNRS, UPE, Champs‐
sur‐Marne, France.
3
CNRS/ TOTAL/ UNIV PAU & PAYS ADOUR E2S UPPA, Institut des sciences analytiques et de
physico‐chimie pour l’environnement et les materiaux, UMR5254, 64000 Pau, France.
Gas hydrates are ubiquitous on earth, notably at the edge of the continental margins and on
the seafloor, where they contribute to the stability of marine sediments by their cohesion
and their adhesion to mineral surfaces. Nowadays there is a great motivation to study the
mechanical behavior of gas hydrates, due to their interests in many energy and
environmental applications. So far, the behavior of gas hydrate bearing sediments depends
largely on the distribution of gas hydrate within the pore space. However, the behavior of
gas hydrate is little or not studied at pore scale. In the literature, three common “pore
habits” are distinguished, considering the existence only of water and hydrate, but not free
gas: pore filing, load bearing and cementing. Recently, studies confirmed the presence and
the abundance of a new pore habit, referred to as “mineral coating”: a few micron‐thin
polycrystalline hydrate shell, not directly covering the sediment particles, but riding on an
equally thin layer of intervening water, sandwiched between the substrate and the gas.
In this study, using optical microscopy, the formation and growth of these shells are
investigated across a water/methane meniscus in glass‐micron capillaries used as model
pores, at 15 MPa of methane pressure. Then by developing a new contactless tensile test in
combination with image processing, mechanical properties of these hydrate shells are
determined. At low enough temperature, the hydrate first grows as a crust over the
meniscus and continues advancing slowly on the gas side as a ‘halo’ riding over a water film
on the glass. The halo comes to rest and adheres to the glass after an annealing period,
effectively completing a hydrate shell (the crust and the halo) that isolates the water from
the gas. During annealing at constant temperature, image processing shows homogeneous
crystal growth of the hydrate shell. Tensile tests are carried out by generating thermally
induced depression in the water compartment at constant methane pressure. Methane
hydrate presents an elastoplastic behavior before brittle fracture. Tensile strength and
elastic modulus are estimated as a function of annealing time (from 4 to 7 hours) and
annealing supercooling (40.3 to 21.8°C). Both are higher at low temperatures, whereas
annealing time seems not to affect the elastic modulus, but the hydrate is more resistant at
short annealing time. Our data contribute to fitting the 5 orders of magnitude gap between
molecular simulations and current experiment at mm to cm scale.
23Journées Hydrates, Brest, 09‐13 septembre 2019
Cascades of hydrate filaments promoted by a porous substrate, activated
charcoal
S. Venet1, R. Brown2, D. Broseta1
1
Laboratoire des fluids complexes et de leurs reservoirs (LFCR), UMR CNRS 5150, Université
de Pau et des Pays de l’Adour, Av. de l’Université, B.P. 1155, 64013 Pau Cedex, France
2
Institut des sciences analytiques et de physico‐chimie pour l’environnement et les matériaux
(IPREM), UMR CNRS 5254, Université de Pau et des Pays de l’Adour, Hélioparc, 2 AV. P.
Angot; 64053 Pau Cedex, France
An unusual gas hydrate morphology, referred to here as “hydrate filaments” or
“hydrate fibres”, is observed in the presence of activated charcoal beads (diam. ca. 400 µm)
under the right conditions of pressure and temperature and bead saturation. This
morphology ensures rapid and uninterrupted hydrate growth, unlike the usual, self‐
frustrating growth of conventional polycrystalline hydrate films at water/guest interfaces.
We use transmission optical microscopy to investigate the growth mechanisms, using
cyclopentane (CP) as the hydrate‐former, because, although its formation requires prior
freezing of water into ice, the hydrate is stable at ambient pressure below a temperature of
7 °C
In order to understand the phenomena involved in this novel growth process, which
has potential applications for water treatment and desalination, we use a single charcoal
bead placed in a square borosilicate capillary used as an optical cell. The temperature is well
controlled over a wide range, from ‐30 °C to room temperature. The capillary is initially filled
with liquid water and CP, and the bead is
most often positioned initially at the
interface (meniscus) between these two
phases, either by introducing from the
CP side or from the water side.
Growth of filaments is most
effective when the bead is pre‐saturated
with CP. Filaments radiate widely from
the bead (several times the bead
diameter). In some experiments, the
guided flow of bubbles indicates the
filaments are hollow.
Possible mechanisms for
continuous hydrate growth will be
discussed, particularly the problem how
growth of continuous hydrate filaments
out of the porous substrate, sidesteps a
self‐extinguishing crust, e.g. is the process similar to hydrate halos reported by Touil et al.1?
[1] Touil, A.; Broseta, D.; Hobeika, N.; Figure 2: Growth of hydrates in the form of filaments
grown from an activated charcoal bead observed under
Brown. R.; Langmuir 33 (2017) 41. optical microscopy (scale bar 500µm). The bead,
initially loaded with CP, lies in water near a CP/water
inteface, now covered with a polycristalline, self-
inhibiting crust of hydrate.
24Journées Hydrates, Brest, 09‐13 septembre 2019
Grain‐scale morphology and distribution of methane hydrates formed in sand
sediment under excess gas conditions
T.X. Le1, M. Bornert1, R. Brown2, P. Aimedieu1, D. Broseta2, B. Chabot1, A. King3, A.M. Tang1
1
Laboratoire Navier (UMR8205 IFSTTAR‐ENPC‐CNRS), Université Paris Est, Marne‐la‐vallée,
France
2
L'Université de Pau et des Pays de l'Adour, France ; 3 Synchrotron SOLEIL, France
Physical/Mechanical properties of sediments containing methane hydrates (MH) depend
considerably on hydrate morphologies and distribution within the porous space. Studies on
MH morphologies and pore distribution in sediments are thus of importance for
interpretations of geophysical data and reservoir‐scale simulation in the scope of methane
gas production. X‐ray computed tomography (XRCT), synchrotron radiation X‐Ray computed
tomography (SXRCT) and optical microscopy have been used to investigate pore‐scale
morphologies and pore distribution of hydrates in sediments. However, it is really
challenging due to not only the need of special experimental setups (high pressure and low
temperature should be maintained) but also poor XRCT image contrast between methane
hydrate and water. In this study, MH growth and morphologies in sandy sediments under
excess gas conditions were investigated by using SXRCT combined with Optical Microscopy.
Both pure and saline waters were used. Mechanisms of MH nucleation/growth are brought
to light thanks to high temporal resolution of SXRCT and Optical Microscopy. Furthermore,
observed MH morphologies and pore repartition compared to existing models (cements,
load bearing and pore‐filling) are discussed. Water moves from menisci to form MH around
nearby sand surfaces. MH morphologies in sample are not only heterogeneous at the pore
scale but also at the sample scale due to water migration. Different types of MH
morphologies (example shown in Figure 1) could exist in the sample.
Figure 3. Images showing different morphologies of MH: (a) crystals; (b) layer (Image
dimensions: 0.63 mm x 0.63 mm)
25Journées Hydrates, Brest, 09‐13 septembre 2019
Insights into the characterization of gas hydrate‐bearing sediments from in
situ geotechnical and acoustic measurements
Garziglia, S., Taleb, F., Sultan, N
IFREMER, REM‐GM, CS 10070, 29280 Plouzané, France
Characterizing the structure and mechanical behaviour of sediments containing gas hydrates
is critical in assessing the potential for slope instabilities as a result either of hydrocarbon
exploitation activities or environmental changes. Concerns over the metastable nature of
gas hydrates have led to a series of investigations aiming at capturing trends in geotechnical
properties as a function of the hydrate content together with the characteristics of the host
matrix under varying stress and thermal conditions. Most efforts in this direction have relied
on the use of synthetic samples under laboratory‐controlled conditions. Some of the trends
that emerged have been confirmed through the analysis of natural samples collected with
pressure corers. The cost of such sampling systems along with the difficulties to preserve
hydrate in their stability conditions has sustained interest in in situ testing methods.
Piezocone sounding is one of the method that has long been considered as particularly well‐
suited as it can provide, at the same time, continuous profiles of three independent
measurements. With the resolution of 2 cm, such profiles are efficient means of picturing
the structure of the subsurface and quantifying the associated changes in mechanical
properties. To complete the characterization of the medium at a similar fine scale, hydrate
contents can be derived from acoustic soundings. Other methods such as dissipation tests
can be carried out with piezometer instruments to determine the permeability properties of
the medium. The aim of this presentation is to synthesize the insight gained by using these
different in situ methods in two distinct areas located offshore Nigeria and in the Black Sea.
Those insights first relate to the characterization of the influence of the quantity and
morphology of hydrates on the properties of their host fine‐grained sediments. They also
proved useful in understanding the processes controlling the large scale distribution of
hydrates in sediments in high gas flux systems.
26Journées Hydrates, Brest, 09‐13 septembre 2019
Mechanical homogenization of gas hydrate bearing soils
A. Alavoine1, P. Dangla1, J.‐M. Pereira1
1
Université Paris‐Est, Laboratoire Navier, UMR 8205 (ENPC‐IFSTTAR‐CNRS), Marne‐la‐Vallée,
France
The research regarding the geomechanics of natural gas hydrate reservoirs in oceanic
sediments of permafrost regions has increased these last two decades. The growing interest
in the potential energy resource that such deposits represent has raised environmental
concerns. Indeed, the dissociation of gas hydrates in soil layers of the seafloor can lead to
instabilities and landslides for example (Kayen, R.; Lee, H.; Marine Geotechnology 10 (1991)
125‐141).
The complexity of the microstructure of soils containing gas hydrates makes it difficult to
model through simple macroscopic mechanical laws. One must take into account
characteristics like hydrate volume fraction, morphology and location in porous media.
Numerical homogenisation techniques allow us to study the apparent behaviour of
heterogeneous microstructures. We use a Fast Fourier Transform based (FFT) method
(Gélébart, L.;Mondon‐Cancel, R.; Comput. Mater. Sci. 77 (2013) 430‐439) to homogenise the
mechanical response of different types of microstructures. Nonlinear mechanical laws like
elastoplasticity can be used for the phases composing the material. Real microstructures can
be homogenised since the technique is based on a space discretisation into pixels.
Furthermore, this numerical solution can be used in multi‐scale approaches or to develop
constitutive laws
27Journées Hydrates, Brest, 09‐13 septembre 2019
GARAH: a GeoERA project addressing knowledge gaps to allow gas hydrate
assessment of the European continental margin
A. Burnol1, I. Thinon1, H. Aochi1, S. Stephant1, Ricardo León2
1
BRGM, 3 avenue Claude Guillemin, 45060, Orléans, France
2
Geological survey of Spain (IGME), Rios Rosas 23, 28003 Madrid, Spain
The main variables controlling the gas hydrate stability zone (GHSZ) are: gas‐composition;
geothermal gradient; pressure (bathymetry); and seafloor temperature. The lack of a
complete available dataset (geological and oceanographic data) in the European continental
margin zone limits our knowledge about key factors controlling the base of GHSZ.
The GeoERA GARAH project (2018‐2021) aims to address gaps in knowledge, and build the
pan‐European gas‐hydrate data infra‐structure necessary to allow assessment of the
European continental margin. This includes objectives to: 1) Develop a harmonized database
of European gas‐hydrate data; 2) Identify specific areas of interest or having critical
knowledge gaps which would benefit from further research; 3) Provide recommendations on
how future data should be collected and stored to be fully interoperable. These objectives
will provide critical information for assessments relating to geohazards and risks,
assessments of the abundance of sediment‐hosted gas‐hydrates, and evaluations of the role
that CO2‐rich hydrates might play for a geological storage of CO2 in deep‐sea sediments
(deep offshore option).
In some areas like the Bay of Biscay and west Galician margins, there is a low density of data.
This year, BRGM contribution was to upload new data concerning this area: thickness of
post‐rift sedimentary layer; Major faults from a bibliographic synthesis; the location of the
theoretical base of the GHSZ supposing a mixed CO2 hydrate with 3.6 mol% N2 in CO2
(Burnol, A; Gas Hydrates 2: Geoscience Issues and Potential Industrial Applications, John
Wiley & Sons, Inc.(2008) 267‐284).
In the next steps of the project, a multi‐risk approach will be taken using this database to
study the potential link between destabilization of gas hydrate and other geohazards like
natural seismicity. GARAH project will thus play a crucial role in advancing our knowledge
about, and modelling of, gas‐hydrate stability along European margins.
Acknowledgment
GARAH project. GeoERA ‐ GeoE.171.002
28Journées Hydrates, Brest, 09‐13 septembre 2019
Influence of alkaline feldspars‐surrogates on the formation kinetic and the
selectivity of CO2‐N2 mixed hydrates under astrophysical and geophysical
conditions
Morgane LEMAIRE1,2, Marc DUSSAUZE2, Claire PETUYA3, Vivian NASSIF4, Claire PIRIM1,
Bertrand CHAZALLON1, Arnaud DESMEDT2
1
Univ. Lille, CNRS, UMR 8523 ‐ PhLAM‐ Physique des Lasers Atomes et Molécules, F‐59000
Lille, France
2
Univ. Bordeaux, CNRS UMR 5255 ISM‐ Institut des Sciences Moléculaires, 33405 Talence,
France
3
JPL NASA PASADENA, 4800 Oak Grove Dr, 91109, Pasadena, U.S
4
Institut Laue Langevin / Institut NEEL CNRS/UGA UPR2940, 38042 Grenoble, France
Clathrate hydrates can be found in a variety of natural environments: marine hydrate‐
bearing sediments, polar ice cores, atmospheric aerosols1,2. Furthermore, they possess a
large potential for useful technical and industrial applications in energy and environmental
fields, such as the prevention of hydrate plugging in oil and gas pipelines, the exploitation of
natural gas hydrates in deep ocean’s sediments or permafrost regions, the storage and
transportation of natural gas in solid hydrate form, and CO2 capture and storage3,4,5,6. In this
work, special interest is given to the natural sediment influence on the CO2/N2 mixed
hydrate.
Aluminosilicates (sodium, calcium and potassium feldspar) are minerals that could be found
on Earth as well as on planets7, moons8 or meteorites8 with Si‐Al substitution and charged
with alkaline. This replacement allows them to have both larger reaction and hydrophobic
surface, promoting CO2‐hydrate dissociation.2 Our recent study, using the high‐resolution
neutron two‐axis powder diffractometer (D1B‐ILL) showed that alkaline surrogates act like
inhibitor of the gas hydrate kinetics of formation. Indeed, the alkaline‐silicate surrogate
could interact with the carbon dioxide and the ice to form carbonates, preventing the
hydrate formation. In order to subsequently investigate their influence on gas hydrate
properties, the selectivity analysis has been carried out on the 50%CO2‐N2 mixed gas hydrate
by means of confocal Raman microspectrometry. It is shown that the presence of alkaline
ions influenced this parameter by decreasing CO2 selectivity. Thus, the chemical composition
of the surrogates, in particular the alkaline, plays a key role in the gas hydrates formation.
The second objective of this work was to understand the influence of these surrogates on
the gas hydrates formation under astrophysical conditions – not well known to the best of
our knowledge. Indeed, most experimental investigations of gas hydrates are performed by
using gas hydrates formed under high pressure and high temperature (with respect to
astrophysical conditions.9,10 In this work, water‐gas deposition experiments have been
performed at astrophysical conditions (i.e. low temperatures and mbar pressure) to form N2‐
hydrate and CO2‐hydrate. In‐situ micro‐Raman spectroscopy, appropriated technique to
investigate gas hydrate11, are used to explore various conditions of formation. It is revealed
that the suitable condition for the hydrate formation appears to be a multi‐layered process.
29Journées Hydrates, Brest, 09‐13 septembre 2019
Such a result is particularly relevant with respect to the dwarfs planets and some moons,
that might enable the formation of a multi‐layered ice in contact with gases.12,13
Acknowledgements: This work is supported by ANR‐15‐CE29‐0016 MI2C. The Institut Laue Langevin is thanked for provision of beam
times. Jennifer Noble (PhLAM – Univ. Lille) is thanked for fruitful and helpful discussions.
(1) Moridis G. J. et al, SPE Reservoir Eval. Eng. 2009, 12 (5), 745−771. (2) Broseta D., et al., Wiley‐ISTE:London, 2017 (3) Seo Y. et al, J.
Chem. Eng. Data 2008, 53, 2833–2837. (4) Kvamme,B. et al, J. Nat. Gas Sci. Eng. 2015. (5) Linga P. et al, Environ. Sci. Technol. 2008, 42,
315–320. (6) Eslamimanesh A. et al, Chem. Eng. Sci. 2012, 81, 319–328. (7) Deer W.A. et al, Geological Society¸2004, London. (8) Castillo‐
Rogez J. et al., Meteorit. Planet. Sci.¸2018, 9, 1820‐1843. (9) Hallbrucker A., J. Chem. Soc. Faraday Trans., 1994, 90(2), 293‐295.//(10) Lunine
J.L., Stevenson D.J., Astrophys. J., 1985, 58, 493‐531 (11) Chazallon B., et al., In : Broseta D., et al., Wiley‐ISTE:London, 2017 (12) Mitri G.,
Showman A.P., Icarus, 2008, 193(2), 387‐396.//(13) Travis B.J., Schubert G., Icarus, 2015, 250, 32‐42.
30Journées Hydrates, Brest, 09‐13 septembre 2019
Clathrate hydrate on planet Mars: at present time and in the past
F. Schmidt1, G. Cruz‐Mermy1, E. Lesage1
1
GEOPS, Université Paris‐Sud, CNRS, France
Clathrate hydrate has been proposed to be present in various geological context in the
Martian history. We propose here to review the condition and the implication of such phase.
At present time: methane has been detected by various techniques in the atmosphere of
Mars, but observations are really puzzling because they suggest a very short (few weeks)
lifetime, in comparison with the known chemistry expectation (tens of years). Methane has
been proposed to as a phase to trap CH4 but also to release it rapidly. Abnormal
preservation of methane clathrate has been proposed to solve this open question. Also,
clathrate may be present in the polar cap of Mars because of the co‐existence of both water
and CO2 ices.
In the past: Most volcanic sulfur released to the early Mars atmosphere could have been
trapped in the upper cryosphere under the form of CO2‐SO2 clathrates. Huge amounts of
sulfur, up to the equivalent of a ~1 bar atmosphere of SO2, would have been stored in the
Noachian (~4Gy) upper cryosphere, then massively released to the atmosphere during the
Hesperian (~3.5 Gy) due to rapidly decreasing CO2 atmospheric pressure. It could have
resulted in the formation of the large sulfate deposits observed mainly in Hesperian terrains,
whereas no or little sulfates are found at the Noachian. We point out the fact that CO2‐SO2
clathrates formed through a progressive enrichment of a preexisting reservoir of CO2
clathrates and discuss processes potentially involved in the slow formation of a SO2‐rich
upper cryosphere. We show that episodes of sudden destabilization at the Hesperian may
generate 1000 ppmv of SO2 in the atmosphere and contribute to maintaining the surface
temperature above the water freezing point.
31Journées Hydrates, Brest, 09‐13 septembre 2019
Clathrate hydrates in the icy worlds of the Solar system
G. Tobie1, E. Le Menn1, L. Bezacier1, Bollengier O.1, Choblet G.1, C. Fauguerolles1, O.
Grasset1, Harel, L. 1, Le Mouélic S.1, Marais, H.1, Massé, M.1, Morizet Y.1, Nna Mvondo, D.1,
Oancea, A.1, Robidel, R.1
1
Laboratoire de Planétologie et Géodynamique, UMR‐CNRS 6112, Université de Nantes,
France
Beyond Mars, most of the solid bodies of the solar system contains water ice in large
quantities, potentially up to 50% of their mass. Space exploration of the Outer solar system
has revealed that several icy bodies harbor liquid water underneath their cold icy surface,
where large quantities of gas compounds may be stored in the form of clathrate hydrate
(Tobie et al. ApJ 752:125 (2012)) The most spectacular discovery of these two last decades
was the observation by the Cassini spacecraft of water vapour and icy grains erupting from
the south pole of Saturn’s moon Enceladus. After ten years of exploration of Saturn’s system
by the Cassini‐Huygens mission, it was understood that this eruption was directly connected
to a subsurface ocean, only a few kilometers beneath the surface (Choblet et al. Nature
Astro. 1 (2017) 841‐947, Postberg et al. Nature 558 (2019) 564‐568). By flying through the
watery plume, Cassini samples for the first time materials coming from an extraterrestrial
water reservoir. Evidence of water vapor erupting from Europa’s surface has been also
reported (e.g. Roth et al. Science 343 (2014) 171‐174), indicating that oceanic materials may
be sampled on this moon also by a future exploration mission.
These different discoveries indicate that active chemical exchanges are still operating on
some of these moons and that gas clathrate hydrate may play a crucial role. In this context,
during these last ten years, the LPG developed a joint approach combining observation,
experimentation and numerical modeling to understand the implications of gas clathrate
hydrate for the long‐term evolution and present‐day activity of icy moons. This includes
high‐pressure experiments (up to 5 GPa) to determine the phase diagram of clathrate
hydrates (mostly CO2 (Bollengier et al. GCA 19 (2013) 322‐339) and CH4 (Bezacier et al. PEPI
229 (2014) 144‐152) in the interior conditions of large icy worlds, acquisition of reference IR
spectra of gas clathrate hydrate at low pressure and low temperature conditions ((Oancea et
al. Icarus 221(2012) 900‐910), Nna Mvondo et al. Icarus (in revision)) in order to anticipate
their detection at the surface of icy moons, numerical modeling on the interior structure to
determine the stability range of clathrate hydrate and their possible transport to the surface
(Tobie et al. ApJ 752:125 (2012), Choblet et al. Icarus 285 (2017) 252‐262)). This presentation
will provide an overview of the work that has been performed these last years by our group
to address the role of clathrate hydrate on the thermo‐chemical evolution of icy moons.
32Journées Hydrates, Brest, 09‐13 septembre 2019
Stability of mixed CH4‐CO2‐N2 hydrates and mass transfer during gas exchange
L.N. Legoix1,2,*, L. Ruffine2, C. Deusner1 and M. Haeckel1
1
GEOMAR, Helmholtz Centre for Ocean Research Kiel, Wischhofst. 1‐3, D‐24148 Kiel,
Germany
2
IFREMER, Institut Français de Recherche pour l’Exploitation de la Mer, Géosciencers
Marines, 29280 Plouzané, France
*Actual affiliation : Université de Lille, PhLAM‐Physique des Lasers Atomes et Molécules, F‐
59000 Lille, France
The CCS processes (i.e., Carbon Capture and Storage) are gaining interest to decrease the
atmospheric emissions of CO2. Clathrate hydrates are components suggested to separate
CO2 from flue gas (i.e., contains mainly N2 and CO2) produced by industries, with the help or
not of a hydrate promoter (Kang, S.‐P. and Lee, H.; Environ. Sci. Technol. 34 (2000) 20).
Concerning the sequestration, the deep‐sea sediments are considered to be a possible
alternative to other geological methods to sequester CO2 in the hydrate form (Ohgaki, K. et
al.; J. Chem. Eng. Jpn 26 (1993) 5). However, the presence of N2 with CO2 could enhance the
process of carbon sequestration, that opens the possibility to sequester directly a flue gas
without using a separation process (Park, D.‐Y. et al.; Proc. Natl. Aca. Sci 103 (2006) 34).
In this work (Legoig, L.N.; Diss. CAU Kiel (2019)), several laboratories experiments were done
to give insights on CO2 sequestration in nature as a hydrate deposit. The phase equilibria
data of CO2‐CH4 hydrates with a liquid CO2 phase shows that it is possible to store CO2 at
higher temperature when CH4 is present. Then, the mechanisms of CH4 replacement by CO2
were studied. Finally, a series of high‐pressure experiments to study the behavior of a fluid
downstream a well for the sequestration of a flue gas were done. The shrinking core kinetics,
based on the diffusion of guest molecules in hydrates, makes the gas exchange slow.
However, CO2 is still preferentially retained compared to N2, and CH4 were produced during
both gas injections and depressurizations steps.
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