Thermodynamic Property Models for Transport and Storage of CO2 - Roland Span, Ruhr-Universitat Bochum, Germany. Presented at CO2 Properties and EoS for Pipeline Engineering, 11th November 2014

1. RUHR-UNIVERSITÄT BOCHUM
Thermodynamic Property Models for
Transport and Storage of CO2
Roland Span
UKCCS Research Centre Meeting, York 2014

2. Options for CCS
Category
Pre-Combustion Process
(IGCC / NGRCC)
Fuel
Lignite
Hard Coal
O2 Supply
Cryogenic
OTM / ITM
CO2 Separation
Physical Absorpt.
Chemical Absorpt.
H2 Membrane
CO2 Membrane
Integrated Process
(Oxy-Fuel)
Cryogenic
OTM / ITM
Condensation
Chemical Looping
Post-Combustion Process
(exhaust gas cleaning)
Chemical Absorpt.
Chilled Ammonia
Solid Adsorbents
Conditioning
Natural Gas
Lignite
Hard Coal
Natural Gas
Lignite
Hard Coal
Natural Gas
Membrane Reactor
Compression, Transport and Storage of CO2
Span | UKCCS Research Centre Meeting | York 2014 2

3. Multi-Disciplinary Property Research
Category
Pre-Combustion Process
(IGCC / NGRCC)
Fuel
Lignite
Hard Coal
O2 Supply
Cryogenic
OTM / ITM
CO2 Separation
Physical Absorpt.
Chemical Absorpt.
H2 Membrane
Property models typical for chemical engineering
CO2 Membrane
Integrated Process
(Oxy-Fuel)
Cryogenic
OTM / ITM
Condensation
Chemical Looping
Post-Combustion Process
(exhaust gas cleaning)
Chemical Absorpt.
Chilled Ammonia
Solid Adsorbents
Natural Gas
Lignite
Hard Coal
Natural Gas
Lignite
Hard Coal
Natural Gas
Membrane Reactor
Conditioning Compression, Transport and Storage of CO2
Span | UKCCS Research Centre Meeting | York 2014 3

4. Multi-Disciplinary Property Research
Category
Pre-Combustion Process
(IGCC / NGRCC)
Fuel
Lignite
Hard Coal
O2 Supply
Cryogenic
OTM / ITM
CO2 Separation
Physical Absorpt.
Chemical Absorpt.
H2 Membrane
CO2 Membrane
Integrated Process
(Oxy-Fuel)
Cryogenic
OTM / ITM
Condensation
Chemical Looping
Post-Combustion Process
(exhaust gas cleaning)
Chemical Absorpt.
Chilled Ammonia
Property models typical for geology / geo sciences
Solid Adsorbents
Natural Gas
Lignite
Hard Coal
Natural Gas
Lignite
Hard Coal
Natural Gas
Membrane Reactor
Conditioning Compression, Transport and Storage of CO2
Span | UKCCS Research Centre Meeting | York 2014 4

5. Multi-Disciplinary Property Research
Category
Pre-Combustion Process
(IGCC / NGRCC)
Fuel
Lignite
Hard Coal
O2 Supply
Cryogenic
OTM / ITM
CO2 Separation
Physical Absorpt.
Chemical Absorpt.
H2 Membrane
Property models typical for energy technologies
CO2 Membrane
Integrated Process
(Oxy-Fuel)
Cryogenic
OTM / ITM
Condensation
Chemical Looping
Post-Combustion Process
(exhaust gas cleaning)
Chemical Absorpt.
Chilled Ammonia
Solid Adsorbents
Natural Gas
Lignite
Hard Coal
Natural Gas
Lignite
Hard Coal
Natural Gas
Membrane Reactor
Conditioning Compression, Transport and Storage of CO2
Span | UKCCS Research Centre Meeting | York 2014 5

6. Multi-Disciplinary Property Research
Category
Pre-Combustion Process
(IGCC / NGRCC)
Fuel
Lignite
Hard Coal
O2 Supply
Cryogenic
OTM / ITM
CO2 Separation
Physical Absorpt.
Chemical Absorpt.
H2 Membrane
CO2 Membrane
Integrated Process
(Oxy-Fuel)
Cryogenic
OTM / ITM
Condensation
Chemical Looping
Post-Combustion Process
(exhaust gas cleaning)
Oxyflame – DFG Collaborative Research Centre
RUB with RWTH Aachen and TU Darmstadt
Chemical Absorpt.
Chilled Ammonia
Solid Adsorbents
Natural Gas
Lignite
Hard Coal
Natural Gas
Lignite
Hard Coal
Natural Gas
Membrane Reactor
Conditioning Compression, Transport and Storage of CO2
Span | UKCCS Research Centre Meeting | York 2014 6

7. Multi-Disciplinary Property Research
Category
Pre-Combustion Process
(IGCC / NGRCC)
Fuel
Lignite
Hard Coal
O2 Supply
Cryogenic
OTM / ITM
CO2 Separation
Physical Absorpt.
Chemical Absorpt.
H2 Membrane
CO2 Membrane
Integrated Process
(Oxy-Fuel)
Cryogenic
Develop a model / a set OTM of models / ITM
which …
• describes homogeneous states with high
(reference) accuracy
• consistently describes VLE / LLE equilibria
• consistently describes equilibria with solid phases
(ice, dry ice, hydrates)
Condensation
Chemical Looping
Post-Combustion Process
(exhaust gas cleaning)
Chemical Absorpt.
Chilled Ammonia
Solid Adsorbents
Natural Gas
Lignite
Hard Coal
Natural Gas
Lignite
Hard Coal
Natural Gas
Membrane Reactor
Conditioning Compression, Transport and Storage of CO2
Span | UKCCS Research Centre Meeting | York 2014 7

8. Thermodynamic Properties of Pure CO2
Span and Wagner (2003),
fundamental EOS with 12 fitted coefficients (high technical quality)
Span and Wagner (1996),
fundamental EOS with 42 fitted coefficients (reference quality)
Span | UKCCS Research Centre Meeting | York 2014 8

9. The GERG-2008 Model by Kunz and Wagner
 Helmholtz-model for mixtures (fundamental equation of state!)
 Introduced independently by Lemmon & Tillner-Roth in mid 90’s
N N N 
1
N
0 r r
       
      
x x T x x x x F
  , ,  , ln   ,   ,
i oi i i oi i j ij ij
m m m m
i i i j i
    
1 1 1 1
Span | UKCCS Research Centre Meeting | York 2014 9

10. The GERG-2008 Model by Kunz and Wagner
 Helmholtz-model for mixtures (fundamental equation of state!)
 Introduced independently by Lemmon & Tillner-Roth in mid 90’s
 Pure fluid equations of state (EOS)
N N N 
1
N
0 r r
       
      
x x T x x x x F
  , ,  , ln   ,   ,
i oi i i oi i j ij ij
m m m m
i i i j i
    
1 1 1 1
Span | UKCCS Research Centre Meeting | York 2014 10

11. The GERG-2008 Model by Kunz and Wagner
 Helmholtz-model for mixtures (fundamental equation of state!)
 Introduced independently by Lemmon & Tillner-Roth in mid 90’s
 Pure fluid equations of state (EOS)
 Mixing rules for reduced input parameters m and m
N N N 
1
N
0 r r
       
      
x x T x x x x F
  , ,  , ln   ,   ,
i oi i i oi i j ij ij
i i i j i
    
 Two options:
m m m m
1 1 1 1
• Mixing rules with four adjustable, binary specific parameters
T x x
r
( )
with ( )
N N

i j

T x x T T
x
x
  
 
m r , , 2 , ,
T x x
N N
  
x x
1 1 1 1
with
 x x
i j
x x

  
    
m i j , ij , ij
2 1 3 1 3
    
x x  
( ) ( ) 8
      
r r 1 1 , , ,
• Combination rules
 0.5
i j T ij T ij c i c j
  

i j T ij i j
1 1 ,
3
i j ij i j c i c j

Span | UKCCS Research Centre Meeting | York 2014 11

12. The GERG-2008 Model by Kunz and Wagner
 Helmholtz-model for mixtures (fundamental equation of state!)
 Introduced independently by Lemmon & Tillner-Roth in mid 90’s
 Pure fluid equations of state (EOS)
 Mixing rules for reduced input parameters m and m
N N N 
1
N
0 r r
       
      
x x T x x x x F
  , ,  , ln   ,   ,
i oi i i oi i j ij ij
i i i j i
    
1 1 1 1
 Binary excess functions
K K K

Pol ij Pol ij Exp ij
 d t  d t
    
   
 (  ,  ) n  k  k n  k  k
exp
     
ij k k k k k k
m m m m m m m m
k k K
 Two options:
m m m m
2
   
, , ,
1 1
  
Pol ij
,
• Binary specific excess function – Fij = 1, parameter in ij fitted
• Generalized excess function – Fij fitted, parameter in ij generalized
Span | UKCCS Research Centre Meeting | York 2014 12

13. The GERG-2008 Model by Kunz and Wagner
 Helmholtz-model for mixtures (fundamental equation of state!)
 Introduced independently by Lemmon & Tillner-Roth in mid 90’s
 Pure fluid equations of state (EOS)
 Mixing rules for reduced input parameters m and m
N N N 
1
N
0 r r
       
      
x x T x x x x F
  , ,  , ln   ,   ,
i oi i i oi i j ij ij
m m m m
i i i j i
    
1 1 1 1
 Four levels of accuracy, depending on available experimental
data and relevance of the binary subsystem
• Only combination rules for Tr, r
• Mixing rules with four adjustable parameters for Tr, r
• Adjusted mixing rules & generalized excess function
• Adjusted mixing rules & binary specific excess function
UNIQUE!
Span | UKCCS Research Centre Meeting | York 2014 13

14. The GERG-2008 Model by Kunz and Wagner
 Helmholtz-model for mixtures (fundamental equation of state!)
 Introduced independently by Lemmon & Tillner-Roth in mid 90’s
 Pure fluid equations of state (EOS)
 Mixing rules for reduced input parameters m and m
N N N 
1
N
0 r r
       
      
x x T x x x x F
  , ,  , ln   ,   ,
i oi i i oi i j ij ij
m m m m
i i i j i
    
1 1 1 1
Methane (CH4) n-Pentane (n-C5H12) Hydrogen (H2)
Nitrogen (N2) Isopentan (i-C5H12) Carbon monoxide (CO)
Carbon dioxide (CO2) n-Hexane (n-C6H14) Hydrogen sulphide (H2S)
Ethane (C2H6) n-Heptane (n-C7H16) Water (H2O)
Propane (C3H8) n-Octane (n-C8H18) Oxygen (O2)
n-Butane (n-C4H10) n-Nonane (n-C9H20) Argon (Ar)
Isobutane (i-C4H10) n-Decane (n-C10H22) Helium (He)
Span | UKCCS Research Centre Meeting | York 2014 14

15. EOS-CG – Improving GERG-2008 for CO2-Rich Mixtures
CO
Ar
O 2
N 2
CO 2
Binary specific excess function
Adjusted reducing functions for r
Lorentz-Berthelot combining rules for r
 5 mixtures: new excess functions
 5 mixtures: new reducing parameters
 r
ij
and Tr
and Tr
Span | UKCCS Research Centre Meeting | York 2014 15

16. Property Models for CO2-Rich Mixtures – EOS-CG
 Example CO2 – Ar: Phase boundaries
 Improvements compared to GERG-2008 at high pressure
Span | UKCCS Research Centre Meeting | York 2014 16

17. Property Models for CO2-Rich Mixtures – EOS-CG
 Example H2O – CO2: Phase Boundaries
Span | UKCCS Research Centre Meeting | York 2014 17

18. Property Models for CO2-Rich Mixtures – EOS-CG
 Example H2O – CO2: Densities
Span | UKCCS Research Centre Meeting | York 2014 18

19. Property Models for CO2-Rich Mixtures – EOS-CG
 Numerically stable (phase-equilibrium) algorithms available
Span | UKCCS Research Centre Meeting | York 2014 19

20. Much Room for Improvement: IMPACTS
Sulphur Trioxide
Sulphur Dioxide
Nitrogen Dioxide
Nitrogen Oxide
Hydrogen Sulfide
Methane
Hydrogen
Carbon Monoxide
Argon
Oxygen
Nitrogen
NIST & WSU
Monoethanolamine Probably covered quite well by existing Helmholtz models
Diethanolamine Helmholtz models available, but accuracy unclear
Hydrogen Chloride Current work at RUB
Binary systems for experimental work within IMPACTS
EOS
Chlorine
Hydrogen Chloride
Diethanolamine
Monoethanolamine
Methanol
Ammonia
Water
Carbon Dioxide
Water
Nitrogen
Oxygen
Argon
Carbon Monoxide
Hydrogen
Methane
Hydrogen Sulfide
Nitrogen Oxide
Nitrogen Dioxide
Sulphur Dioxide
Sulphur Trioxide
Ammonia
Methanol
Chlorine
Major
Minor Components Components
Span | UKCCS Research Centre Meeting | York 2014 20

21. Low-Temperature Phase Equilibria for CO2
• CO2 in pipelines is liquid
• Pressure loss (leaks or flooding of
evacuated pipeline segments)
results in liquid / vapor system
• Further expansion leads to
formation of a dry ice / vapor
system at about 195 K
• For a description of the process
(enthalpy) flash calculation with
solid phase
• Similar effects for low tempera-ture
transport / capture
 Consistent fundamental equation
for dry ice required!
Span | UKCCS Research Centre Meeting | York 2014 21

22. Phase Equilibria with Solid Phases – Dry Ice
 Fundamental equations for solid CO2 (dry ice) developed
 Jäger and Span (2010, 2012): Gibbs enthalpy as a function of
pressure and temperature
 Approach by Tillner-Roth (1998) adapted
 Fitted only to data for solid CO2
T T p
c T p
( , )
0
p
g p T h Ts c T p T T T v p T p
( , )    ( , )d  d  ( , )d
0 0  p
0
  T
T T p
0 0 0
 Trusler (2011): Helmholtz energy as a function of molare volume
and temperature
 Fitted also phase equilibrium with adjacent fluid-phase
Span | UKCCS Research Centre Meeting | York 2014 22

23. Phase Equilibria with Solid Phases – Dry Ice
 Intersection with Gibbs enthalpies from EOS for fluid states yields
consistent SVE / SLE data (sublimation / melting pressure)
 Allows for flash calculations into the melting / sublimation region
Intersection with
Span and Wagner (1996)
Intersection with
Ely (1987)
 The property model used for the fluid phases has a significant
impact!
Span | UKCCS Research Centre Meeting | York 2014 23

24. Phase Equilibria in the System CO2 / H2O
Fluid region:
H2O: Wagner and Pruss (2002)
CO2: Span and Wagner (1996)
Mixing rules: Gernert and Span (2013)
Solid H2O: Feistel and Wagner (2006)
Solid CO2: Trusler (2011) / Jäger and Span (2010, 2012)
Hydrates: Jäger, Vinš, Hrubý, and Span, R. (2013)
Span | UKCCS Research Centre Meeting | York 2014 24

25. Phase Equilibria with Solid Phases – Hydrates
• The model of Ballard und Sloan (2002) was chosen and
slightly modified:
 
      , , , , ln 1 , H
w J w i i J J
T p f g T p RT v C T p f  
 
    
 
i J
Span | UKCCS Research Centre Meeting | York 2014 25

26. Phase Equilibria with Solid Phases – Hydrates
• The model of Ballard und Sloan (2002) was chosen and
slightly modified:
 
      , , , , ln 1 , H
w J w i i J J
T p f g T p RT v C T p f  
 
    
 
i J
• Adjustable parameters of the model:
1 2  , ,0 ,0 , w w g h    ,
Pressure dependence Reference state
of the molar volume
Potential-parameters
consistency to reference
state of fluid model
fitted but almost
unchanged fitted to (T,p)-data generated from
experimental data & fluid model
Span | UKCCS Research Centre Meeting | York 2014 26

27. Phase Equilibria with Solid Phases – Hydrates
Intersection with EOS-CG yields
equilibrium temperatures with
deviations < 1 K to exp. data
LcH
VH
VIw
HIc
VLc
VLw
 Accurate description of CO2 / H2O hydrate formation
 Consistent to accurate VLE / LLE / homogeneous phase model
Span | UKCCS Research Centre Meeting | York 2014 27

28. Allowable Water Content in CO2
Span | UKCCS Research Centre Meeting | York 2014 28

29. Allowable Water Content in CO2
Span | UKCCS Research Centre Meeting | York 2014 29

30. TREND – Software Made Available
• TREND 1.1 was made available early in 2014
• Launch of TREND 2.0 is expected by the end of 2014
Preview
TREND 2.0
Span | UKCCS Research Centre Meeting | York 2014 30

31. Other Hydrates
• Hydrate models (consistent to accurate multiparam. mixture
models for fluid phase) will soon be published for water with
- Nitrogen
- Oxygen
- Argon
- Carbon monoxide
- Methane
- Ethane
- Propane
• A corresponding model for mixed hydrates is still pending
Span | UKCCS Research Centre Meeting | York 2014 31

32. Avoiding Inconsistencies – Injection of CO2
• Engineers working on pipelining of CO2 use GERG-2008 / EOS-CG
• Reservoir engineers use cubic EOS (+ hydrate / electrolyte models)
• Severe inconsistencies, e.g., for injection of CO2 (-rich mixtures)
Pipeline engineer delivers
500 to/h  577 m3/h at 19.6 MPa
Reservoir engineer receives
577 m3/h at 18.1 MPa  440 to/h
Span | UKCCS Research Centre Meeting | York 2014 32

33. Avoiding Inconsistencies
• CO2 in geological storage
 Mixtures with brines instead of water
• CO2 capture from natural gas / two phase gas pipelines
 Mixed hydrates
 Mixtures with hydrate inhibitors
• CO2 scrubbing from flue gas / natural gas
 Systems containing scrubbing agents
• CO2 ….
In the long run the main challenge will
be to ensure that property models used
in adjacent process steps are consistent
to accurate models applied for CO2 transport
Span | UKCCS Research Centre Meeting | York 2014 33

34. Thank you for your attention!
The author is grateful to all organizations that
contributed funding to the presented work, namely to
- E.ON for awarding an E.ON Research Award
- E.ON Ruhrgas for the contract "Calculation of Complex
Phase Equilibria"
- the federal government of Nordrhein Westfalen in
conjunction with EFRE for funding under contract
315-43-02/2-005-WFBO-011Z
- the European Commission for the contract
"Seventh Framework Program, Nr. 308809, IMPACTS“
- the DFG for the framework of the collaborative research
centre ”Oxyflame“
Span | UKCCS Research Centre Meeting | York 2014 34

35. The „Killer Application“
• If a CO2 pipeline leaks, the
mantle cools down drastically, the
material becomes brittle
• The crack propagates in both
directions
• The pressure loss propagates
with about speed of sound
• If the crack propagates faster
than speed of sound, small
cracks result in a disaster
 The issue is a safety issue,
accurate properties required for
homogeneous, VLE, VLSE states
• Accurate properties are certainly
more important for other
applications, but who cares …
cold CO2 escapes
liquid CO2 in the pipeline
Pipeline wall
SINTEF
Span | UKCCS Research Centre Meeting | York 2014 35

36. International Cooperation
Focus on CO2-rich mixtures
• Measurement of thermodynamic properties (pvT, w)
• Measurement of phase equilibria (VLE, LLE, VLSE)
• Measurement of transport properties (viscosity)
• Accurate property models for CO2-rich mixtures
• Description of phase equilibria including solid phases
• Improvement of phase equilibrium algorithms
• Test of new property models for various applications
Span | UKCCS Research Centre Meeting | York 2014 36