Presentation given by George Romanos of the National Center for Scientific Research “Demokritos” (NCSRD), Greece, on "CO2QUEST - Fluid Properties and phase behaviour of CO2 with impurities" at the EC FP7 Projects: Leading the way in CCS implementation event, London, 14-15 April 2014

1. CO2QUEST-Fluid Properties and phase
behaviour of CO2 with impurities
Dimitrios Tsangaris, Ioannis G. Economou and Nikolaos I. Diamantonis
National Center for Scientific Research “Demokritos”,
Institute of Advanced Materials, Physicochemical Processes,
Nanotechnology and Microsystems,
Aghia Paraskevi Attikis, Greece
and
Texas A&M University at Qatar,
Chemical Engineering Program,
Doha, Qatar

2. Pipeline transport of CO2 in CCS
• CO2 at supercritical conditions (Tc = 31oC,
Pc = 73.8 bar).
• Bi-phase flow to be avoided (high density,
low viscosity, high cost).
• The part of transport of CO2 in the CCS
process is frequently overlooked.
• Not enough knowledge on the design of CO2
transport pipeline systems, especially in
densely populated areas.
Koornneef, J. et al., J
Hazard Mater 177,
12, (2010)
Barrie, J. et al.,
Greenhouse Gas
Control Technologies
7, 2004: Canada

3. Pipeline Transportation of CO2
Pipeline rupture → Depressurization of supercritical CO2 → Dispersion
and phase transitions
Behavior will depend on the mixture composition emitted by industry.
Source: Project Proposal of “Quantitative failure consequence hazard assessment for next generation
CO2 pipelines: The missing link”, CO2PIPEHAZ, EU FP7 funded project

4. Typical CO2 stream composition
The flow stream in the pipeline comes from fuel combustion and
contains the following components:
CO2, N2, O2, H2O and traces of SO2 and NO
Source: Report from DUT for CO2PIPEHAZ, EU FP7 funded project
Captured CO2 stream is produced after separation process on the flue gas

5. Generalized
cubic EoS
3 * * 2 * *2 * *2 * * *2 *3
* *
2
(1 ) ( ) 0
,
z B uB z A B uB uB z A B B B
aP bP
A B
RT RT
ω ω ω− − − + + − − − − − =
= =
Cubic equations of state
EoS
RK
u=1, w=0
SRK
u=1, w=0
PR
u=2, w=-1
PR/G
u=2, w=-1
Diamantonis N.I., Boulougouris G.C., Mansoor E., Tsangaris D.M.,
and Economou I.G., Ind. Eng. Chem. Res. 52, 3933 – 3942 (2013).

6. Peng-Robinson EoS
Peng-Robinson EoS vdW mixing rules
Repulsion Attraction
Peng, D.-Y.; Robinson, D. B., A New Two-Constant Equation of State.
Ind. Eng. Chem. Fund. 1976, 15, 59-64.

7. Temperature dependent functions investigated in this work
Peng and Robinson: Gasem et al.:
Peng, D.-Y.; Robinson, D. B., A New Two-Constant Equation of State. Ind. Eng. Chem.
Fund. 1976, 15, 59-64.
Gasem, K. A. M.; Gao, W.; Pan, Z.; Robinson Jr, R. L., A modified temperature dependence
for the Peng–Robinson equation of state. Fluid Phase Equilibr. 2001, 181, 113-125.
Better for pure CO2 !

8. SAFT and PC-SAFT basics
Chapman, Gubbins,
Jackson, Radosz, Ind. Eng.
Chem. Res. 29, 1709
(1990)
Gross, Sadowski, Ind. Eng.
Chem. Res. 40, 1244
(2001)
Karakatsani, Spyriouni,
Economou, AIChE J., 51,
2328 (2005)

9. PHASE EQUILIBRIA

10. Optimization of parameters for binary systems
Optimized kij values for
binary systems of
CO2 with
O2, N2, H2S, SO2,
Ar, CH4,
were calculated.
Diamantonis N.I., Boulougouris G.C., Mansoor E., Tsangaris D.M., and
Economou I.G., Ind. Eng. Chem. Res. 52, 3933 – 3942 (2013).
On average PC-SAFT performs more accurately than
the cubic EoS investigated, with PR following slightly
behind.
CO2 – CH4
CO2 – H2S

11. CO2 – H2O phase equilibria
Diamantonis, N.I.; Economou, I.G., Mol. Phys. 2012,110, 1205-1212.
H2O solubility in CO2 CO2 solubility in H2O
Solid lines: PC-SAFT
Dashed lines: PC-SAFT + polar
(tPC-PSAFT)

12. Ternary and multicomponent mixtures
Flash calculations for a 12-component mixture
forming from the addition of CO2 to a synthetic oil.
Expt. Data for the CO2-N2-O2: Muirbrook and Prausnitz, 1965
Expt. Data for the 12-component: Turek et al. 1984
kij values for binary systems with alkanes: Knapp et al, 1982
kij values for binary systems with gases: This work.
K-factors at 273 K for the individual
components in the ternary CO2 – N2
– O2 mixture.

13. DERIVATIVE PROPERTIES

14. Derivative properties brief background
• Isobaric heat capacity, Cp
• Speed of sound, w
• Joule-Thomson coefficient
Derivative properties are essential for many processes
design
i.e. Pipeline rupture → Constant H → J-T coefficient drives design
All expressions are derived analytically within SAFT/PC-SAFT
framework
P
p
T
H
C 





∂
∂
=
Tv
p P
C
C
w 





∂
∂
=
ρ
HP
T






∂
∂
=µ

15. Derivative thermodynamic properties of pure CO2
Joule-Thomson coefficient
of pure CO2
Speed of sound of pure
CO2
Residual isochoric heat capacity of pure CO2 for subcritical and
supercritical regimes
Diamantonis, N. I.; Economou, I. G.,
Energy and Fuels 2011,25, 3334-3343

16. Accuracy of prediction of derivative properties
• The deviation is less
than 10% AAD.
• J-T coefficient (μ) gives
the highest deviation of
all the properties.
• The associating model
for H2S does not improve
the predictions of
derivative properties.
Diamantonis, N. I.; Economou, I. G.,
Energy and Fuels 2011,25, 3334-3343

17. Speed of sound for CO2 – CH4 mixture
Expt. Data: Alsiyabi, I.; Chapoy, A.; and Tohidi, B., Effects of impurities on
speed of sound and isothermal compressibility of CO2-rich systems, 3rd
International Forum on the Transportation of CO2 by Pipeline, Gateshead, UK,
20-21 June 2012
Solid lines: PR, long dashed: SAFT,
short dashed: PC-SAFT
SAFT and PC-SAFT can
follow the trend of the
experiments, but it’s not
the case for PR.
SAFT shows lower error
than PC-SAFT in low
pressure and low
temperature, but PC-SAFT
performs better overall.

18. Effect of composition on J-T inversion curve
of CO2 – CH4
AAD% < 10% for the
equimolar mixture and the
pure CO2
compared with data from:
J. Vrabec, A. Kumar and H.
Hasse, Fluid Phase
Equilibr., 258, 34-40 (2007)

19. TRANSPORT PROPERTIES -
VISCOSITY

20. Pure components Mixing rules
Chung’s theory for dilute gas limit
Repulsive and attractive term of pressure from Eos
are required to calculate the dense-state correction
a1, a2, b1, b2, c2 are pure component parameters
that are regressed for each EoS used
(parameters already regressed for the pure
components of interest for the EoS PC-SAFT and
tPC-PSAFT)
S.E. Quiñones-Cisneros, C.K. Zéberg-Mikkelsen and E.H.
Stenby, Fluid Phase Equilibr. 169, 249-276 (2000)
Friction Theory (FT) overview

21. Viscosity for CO2-CH4 and CO2-N2 with PC-SAFT and tPC-PSAFT
Expt. Data: J. Kestin and J. Yata, J. Chem.
Phys. 49, 4780-4791 (1968).
Expt. Data: Kestin, J.; Kobayashi, Y.; Wood, R. T., The
viscosity of four binary, gaseous mixtures at 20° and
30°C. Physica 32, 1065-1089 (1966)

22. Ternary systems
Expt. Data: Gururaja, G. J.; Tirunarayanan, M. A.; Ramachandran,
A., Dynamic viscosity of gas mixtures. J. Chem. Eng. Data 12, 562-
567 (1967)
Calculations were extended to ternary systems with available experimental data.
The combination of PC-SAFT with Friction Theory exhibits very good behavior for
CO2-O2-N2 at ~1bar, with an AAD of 0.53%
Errors continue to be of the same magnitude than the binary CO2-CH4. At P=1bar,
the AAD% is 5.51%
Expt. Data: J. Kestin and S.T. Ro, Berich. Bunsen.
Gesell. 78, 20-24 (1974)

23. Conclusions
• Equations of state (EoS) can be used to predict accurately
phase equilibria and derivative thermodynamic properties of
CO2 mixtures.
• They can be also used for the prediction of transport properties
of pure components and mixtures.
• Temperature independent binary interaction parameters can
improve the model accuracy.
• Higher order EoS are more accurate than cubic EoS for the
case where no binary parameters are used; otherwise, they are
comparable.
• EoS can be reliably used for process design.

24. Acknowledgments
Financial support from the 7th European Commission
Framework Program for Research and Technological
Development for the project “Quantitative failure
consequence hazard assessment for next generation CO2
pipelines”, no: 241346 (2009 – 2013).
Abu Dhabi Company for On-shore Oil Operations
(ADCO) via the project “Thermodynamic Model
Development for the ADCO CO2 EOR”
The Petroleum Institute for a visiting Ph.D. scholarship
to NID.