Gas Hydrates in Energy Recovery, Transportation & Storage
K.C. Hester, A. Gupta, L.J. Rovetto, H. Ohno, S. Wierzchowski J. Boxall, S. Davies, J. Nicholas, P. Rensing, T. Strobel, D. Greaves, J. Lachance, M. Walsh L. Dieker, C. Timm, G. Green, A. Hughson, A. Papineau, B. Sikora S.F. Dec, K.T. Miller, E.D. Sloan, Jr. (Director), C.A. Koh (Co-director), Energy Seminar, Stanford University, April 18, 07 Center Center for for Research Research on on Hydrates Hydrates & & Other Other Solids, Solids, Colorado Colorado School School of of Mines Mines
Outline What are hydrates? Why are they important? Controlling hydrate formation/decomposition Highlights of CHR research • Ocean Raman studies of natural seafloor hydrates • Hydrate decomposition for energy recovery • Hydrogen storage in clathrate hydrates • Hydrates in flow assurance • Molecular tools for hydrate formation/decomposition studies
Future directions Center Center for for Research Research on on Hydrates Hydrates & & Other Other Solids, Solids, Colorado Colorado School School of of Mines Mines
What are Clathrate Hydrates? Hot Stuff!
Crystalline solids • Like ice Made of water cages Traps “guest” molecules • e.g. methane, carbon dioxide
Concentrate large volumes of gas • ~170 m3 of gas (STP)/m3 hydrate Center Center for for Research Research on on Hydrates Hydrates & & Other Other Solids, Solids, Colorado Colorado School School of of Mines Mines
Clathrate Hydrate Structures 51262
6/cell
51264
8/cell
Center Center for for Research Research on on Hydrates Hydrates & & Other Other Solids, Solids, Colorado Colorado School School of of Mines Mines
Why Are Hydrates Important?
Center Center for for Research Research on on Hydrates Hydrates & & Other Other Solids, Solids, Colorado Colorado School School of of Mines Mines
Potential Future Energy Resource Current Estimates 1015-1017 m3 Hydrated Gas
Mallik2002 Gas: 468SCM in 125 hrs
GAS
Center Center for for Research Research on on Hydrates Hydrates & & Other Other Solids, Solids, Colorado Colorado School School of of Mines Mines
Economic & Safety Risks of Hydrate Formation in Pipelines
Center Center for for Research Research on on Hydrates Hydrates & & Other Other Solids, Solids, Colorado Colorado School School of of Mines Mines
Safety Models Could Prevent Accidents Pupstream
friction
∆P
Pdownstream
Newton’s Laws of Motion describe the position, velocity & acceleration of the plug
Hydrate Accident
Approach to Control Clathrate Hydrates CSMHyK-OLGA Multiphase Flow Model & Flowloop Data
Sensitivity analysis of kinetic parameters & fluids
Diffraction, Raman, NMR Molecular Simulations, Mechanisms of growth, inhibition, decomposition
Prediction Models for Energy Recovery, Transportation, and Storage Hydrate agglomeration
MMF, PSA, DSC Rheology
Hydrate phases as a function of time
Raman, NMR, Diffraction, DSC, X-ray CT, Visual
Center Center for for Research Research on on Hydrates Hydrates & & Other Other Solids, Solids, Colorado Colorado School School of of Mines Mines
Highlights of CHR Research
Center Center for for Research Research on on Hydrates Hydrates & & Other Other Solids, Solids, Colorado Colorado School School of of Mines Mines
In situ ocean hydrate measurements
Center Center for for Research Research on on Hydrates Hydrates & & Other Other Solids, Solids, Colorado Colorado School School of of Mines Mines
Ocean Raman Studies of Natural Seafloor Hydrates Keith C. Hester (Ph.D. thesis)
MBARI ROV Tiburon Precision Underwater Positioner
LRS in housing Raman probe
Barkley Canyon Expedition August 10-19, 2006 K.C. Hester, E.D. Sloan (CSM) P.G. Brewer, E.T. Peltzer, P. Walz, R.M. Dunk (MBARI)
(Chapman, (Chapman, 2004) 2004)
Natural hydrate mounds
In Situ Raman Measurement
51262
In situ Ocean Raman spectra of sI methane hydrate 512 methane CH Stretching region
H2O OH Stretch
Coexistence of sI/sII measured in situ SO42-
C2H6, sII
CH4, sI/sII L
CH4, sI/sII S
Intensity (A.U.)
C2H6, sI
C3H8 i-C4H10 *
White hydrate
Raman Shift (cm-1)
*
*
Hydrate cored recovered for laboratory measurements Both pressurized and non-pressurized Lab tools • Raman and NMR • X-ray diffraction
Center Center for for Research Research on on Hydrates Hydrates & & Other Other Solids, Solids, Colorado Colorado School School of of Mines Mines
sII, sH Confirmed by XRD
Yellow hydrate Center Center for for Research Research on on Hydrates Hydrates & & Other Other Solids, Solids, Colorado Colorado School School of of Mines Mines
Experiments & Simulations of Hydrate Decomposition for Energy Recovery
Density (kg/m3)
Arvind Gupta (Ph.D. thesis) Collaboration with LBNL Center Center for for Research Research on on Hydrates Hydrates & & Other Other Solids, Solids, Colorado Colorado School School of of Mines Mines
0.30 0.50 0.70 0.90 1.10
Density (g/cm3)
1.30
Hydrate Plug Decomposition Studies Using CT X-ray Measurements
Coolant
Tedge
Touter Tinner Tcenter
Center Center for for Research Research on on Hydrates Hydrates & & Other Other Solids, Solids, Colorado Colorado School School of of Mines Mines
Density Profile Variation of the Hydrate Plug 1000 Zone 2
Zone 1
Zone 3
(Transition zone)
3
Average Density (kg/m )
800
600
400
200 Expt_ Avg. Density
0 0.0
0.5
1.0
1.5 2.0 2.5 Radial Position (cm)
3.0
3.5
Center Center for for Research Research on on Hydrates Hydrates & & Other Other Solids, Solids, Colorado Colorado School School of of Mines Mines
H2 Storage in Clathrate Hydrates Florusse et al. Science (2004): Binary THF-H2 hydrate (CSM & TU Delft) 1000
Pressure reduction 2 orders of magnitude
Pressure (MPa)
Pure H2
100
H2/THF Hydrates Stable H2/THF
10
Pure THF
Hydrates Melt 1 270
275
280
285
290
Temperature (K)
Center Center for for Research Research on on Hydrates Hydrates & & Other Other Solids, Solids, Colorado Colorado School School of of Mines Mines
295
300
Capillary Tube holds~400 MPa
High P Raman Studies of H2 Hydrates Trends in H-H vibron peaks (Tim Strobel, PhD student)
Free H2, 200 MPa 295 K
Dissolved H2, 200 MPa 295 K
Clathrate, 200 MPa 250 K Raman Shift cm-1 Center Center for for Research Research on on Hydrates Hydrates & & Other Other Solids, Solids, Colorado Colorado School School of of Mines Mines
Single H2 Occupancy Confirmed in Binary THF sII Hydrate Hester et al. J. Phys. Chem. (2006) Strobel et al. J. Phys. Chem. B (2006)
1a THF-d8 sII hydrate
12
Normalized Intensity
F rac tio n al O cc u p a n c y o f H 2 in 5 12 C ag e
1 H2 / 5 cage
1.0
0.8
0.6 Crushed THF Hydrate 45 microns Crushed THF Hydrate 250 microns Udachin (1994) Best Fit Langmuir Isotherm
0.4
1b D2 + THF-d8 sII hydrate
0.2
0.0 0
100
200 300 Hydrogen Fugacity (MPa)
400
500
D-spacing (Å) DCenter Center for for Research Research on on Hydrates Hydrates & & Other Other Solids, Solids, Colorado Colorado School School of of Mines Mines
H2 can stabilize sII binary hydrate with cyclohexanone Strobel et al., 2007
Center Center for for Research Research on on Hydrates Hydrates & & Other Other Solids, Solids, Colorado Colorado School School of of Mines Mines
H2 Occupancy in Binary & Pure H2 Hydrates: 1 H2 in sII 512 Cage & 1-4 H2 in 51264 Cage
Binary CHONE/H2 hydrate 10.0
Pure H2 hydrate
Rwp (%)
Neutron Intensity
9.0 8.0 7.0 6.0 5.0 0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
Fractional Occupancy of D2
1.0
2.0
3.0
4.0
5.0
D-spacing (Å)
Strobel et al., 2007
Lokshin et al., 2004
Hester et al., J. Phys.Chem. B, 2006 Strobel et al., J. Phys. Chem. B, 2006 Center Center for for Research Research on on Hydrates Hydrates & & Other Other Solids, Solids, Colorado Colorado School School of of Mines Mines
Hydrates in Flow Assurance
Center Center for for Research Research on on Hydrates Hydrates & & Other Other Solids, Solids, Colorado Colorado School School of of Mines Mines
On the Cusp of a Hydrate Change
Avoidance Avoid Hydrate T&P • Thermodynamics • Time Independent • Within 1.4oF; 10%(P)
Avoid T&P • Insulation • Inhibitor Injection
Management Prevent Blockages • Kinetics • Time Dependent • No Agglomeration
Examples • • • •
Anti-Agglomerants Slurry Flow Plug Remediation Electrical Heating
Center Center for for Research Research on on Hydrates Hydrates & & Other Other Solids, Solids, Colorado Colorado School School of of Mines Mines
Conceptual Model of Hydrate Formation in Oil-Dominated System water entrainment
water drops form hydrate shells, ptle size unchanged (D.Turner)
plug
agglomeration
gas oil water hydrate shells
time capillary attraction
Agglomeration Prevention = Plug Prevention
Center Center for for Research Research on on Hydrates Hydrates & & Other Other Solids, Solids, Colorado Colorado School School of of Mines Mines
Model Development to Predict Hydrate Blockages FBRM/PVM – Particle Size Analysis & Agglomeration
MMF – Adhesion Forces Film Growth & Film Strength
CSMHyK/OLGA 2000 Simulator Hydrate Growth in Multiphase Pipeline Flow
Flow Loops (Texaco, ExxonMobil, TU)
HP-DSC Agglomeration
Rheometers
Center Center for for Research Research on on Hydrates Hydrates & & Other Other Solids, Solids, Colorado Colorado School School of of Mines Mines
Hydrate Agglomerate Morphology Determined with Simultaneous PSD FBRM
0 10 20 30 40 50 60
60
40 30 20
15:00
10
PVM
fD 13:00
80 60
(J.Boxall)
Chord
40 20 Leng th [um ]
0
Center Center for for Research Research on on Hydrates Hydrates & & Other Other Solids, Solids, Colorado Colorado School School of of Mines Mines
12:00
eo
0
T im
D. Greaves
14:00
ay
C ho rd C ou nt
50
DSC Tests of the Effect of Hydrates on Emulsion Stability Primary hydrate particle Hydrate shell
sII Hydrate Melting
Water Droplet
Water core
Emulsion
Hydrate Formation
Emulsion after hydrate dissociation
J. Lachance
(Redrawn from Palermo et al. 2005)
Center Center for for Research Research on on Hydrates Hydrates & & Other Other Solids, Solids, Colorado Colorado School School of of Mines Mines
Molecular Tools to Study Hydrate Formation & Decomposition
Center Center for for Research Research on on Hydrates Hydrates & & Other Other Solids, Solids, Colorado Colorado School School of of Mines Mines
Time-Resolved NMR 13C MAS NMR of CH –C H Hydrate 4 2 6 51262 cages decompose faster than 512 cages C2 gas phase C2 large cage
C1 C1 small large cage cage
C1 gas phase
Time (s)
Dec et al., J. Phys. Chem. B, 2007 Center Center for for Research Research on on Hydrates Hydrates & & Other Other Solids, Solids, Colorado Colorado School School of of Mines Mines
Molecular-level Studies of Hydrate Formation & Decomposition H
O
H
I
O
H
Neutron source
H
O Q
H2O (l) + CnH2n+2 (g) @ 50-350 bar, 4-25 oC
H
Neutron Diffraction pattern
H
EPSR analysis
Hydration structure during hydrate formation & decomposition Buchanan, Soper, Koh et al., J.Chem. Phys. (2005) Thompson, Soper, Koh et al., J. Chem. Phys. (2006) Center Center for for Research Research on on Hydrates Hydrates & & Other Other Solids, Solids, Colorado Colorado School School of of Mines Mines
lij
Hydration Shell Expands on sI & sII Hydrate Formation Hydrate
Liquid
~1-2 Å expansion
sI sII
Increased order
Center Center for for Research Research on on Hydrates Hydrates & & Other Other Solids, Solids, Colorado Colorado School School of of Mines Mines
Hydrate Decomposition Over 21 hours To Remove Bragg Peaks 4500 4000
Roberts 1940 Deaton&Frost 1946 Kobayashi 1949
Pressure (psi)
3500 3000
McLeod&Campbell 1961 Marshall&Kobayashi 1964 Jhaveri&Robinson 1965
2500 2000 1500
Methane Hydrate
Gallow ay 1970
Decomposition (21 hrs) Formation
Falabella 1975 Verma 1974 de Roo 1983
12 hrs
9 hrs
Thakoe&Holder 1987 1000
Methane + Water
500 0 -10
-5
0
5
10
15
20
25
Tem perature (oC)
Investigating the well-documented ‘memory effect phenomenon’
Center Center for for Research Research on on Hydrates Hydrates & & Other Other Solids, Solids, Colorado Colorado School School of of Mines Mines
“Memory effect” causes more rapid nucleation What causes the “memory effect”? • Residual amorphous structure, residual crystallites, or dissolved gas Decreasing Metastability On Hydrate Reformation
Center Center for for Research Research on on Hydrates Hydrates & & Other Other Solids, Solids, Colorado Colorado School School of of Mines Mines
No Change in Water Structure & Hydration Shell Before Formation & After Melting Before formation (points), after melting (solid lines) 5.0
7
HW-HW
4.5
6 4.0
C-HW
3.5
5
OW-HW
3.0
g(r)
g(r)
4
3
2.5 2.0 1.5
2
C-OW
1.0
OW-OW 1
0.5 0.0
0 0
2
4
6
r [Å]
8
10
0
2
4
6
8
r [Å]
‘Residual’ crystallites rather than amorphous structure attributed to the ‘memory effect’ phenomenon. Center Center for for Research Research on on Hydrates Hydrates & & Other Other Solids, Solids, Colorado Colorado School School of of Mines Mines
10
Future Directions: New Paradigms in Gas Hydrate Technology Improve Understanding & Control of Kinetics in: Gas recovery from hydrate deposits • assess dissociation techniques Assessing submarine hydrate dissolution rates • impact of dissociation to the environment Energy storage materials • develop synthesis & stability technologies Maintaining flow in pipelines • determine when & where a plug occurs Center Center for for Research Research on on Hydrates Hydrates & & Other Other Solids, Solids, Colorado Colorado School School of of Mines Mines
Acknowledgements Funding: National Science Foundation American Chemical Society Department of Energy – Basic Energy Sciences National Undersea Research Program Minerals Management Services CSM Hydrate Consortium: BP, Chevron, CononcoPhillips, ExxonMobil, Halliburton, Petrobras, Schlumberger, Shell DeepStar Consortium Collaborators: MBARI (P. Brewer, E. Peltzer) LBNL (G. Moridas, T. Kneafsey) RAL-ISIS, U.K. (A.K. Soper); ANL-IPNS (A.Schultz) CVX (J.L. Creek); NTNU, Norway (J. Sjoblum); IFP, France (T. Palermo) CSM (Matthew Liberatore, John Dorgan) Center Center for for Research Research on on Hydrates Hydrates & & Other Other Solids, Solids, Colorado Colorado School School of of Mines Mines