Presentation given by Luis Pereira (on behalf of Antonin Chapoy) from Heriot-Watt University on "Impacts of impurities on thermophysical properties and dehydration requirements of CO2-rich systems in CCS" in the Effects of Impurities Technical Session at the UKCCSRC Biannual Meeting - CCS in the Bigger Picture - held in Cambridge on 2-3 April 2014

1. 1
Impact of impurities on thermophysical
properties and dehydration requirements
of CO2-rich systems in CCS
L. Pereira, M. Kapateh, A. Chapoy
Centre for Gas Hydrate Research, Institute of Petroleum Engineering, Heriot-Watt
University, Edinburgh EH14 4AS, UK
UKCCSRC Biannual, 2-3 April, Cambridge

2. Outline
• Introduction / Background
• VLE / Phase Equilibria
• Hydrate / dehydration
• Viscosity / density
• Frost Points
• Conclusions / Future Work
2 UKCCSRC Biannual, 2-3 April, Cambridge

3. Background
• 3 years project in collaboration with ENSMP started in 2012
• Main objective: developing a reliable thermodynamic package for
CCS fluids
• CO2 originating from capture processes is generally not pure and
can contain impurities such as:
– H2O, CH4, N2, H2, NyOx, H2S, SO2…
• The main aim of the proposed project is to investigate the phase
behaviour and properties of CO2-rich stream containing impurities
• Phase behaviour of saline water and CO2-rich streams
• Impurities in this project:
– H2O, CH4, C2H6,C3H8, N2, H2, O2, Ar, CO, NyOx, H2S, SO2…
3 UKCCSRC Biannual, 2-3 April, Cambridge

4. Research Topics
• Phase Equilibria (VLE, Phase Envelope)
• Hydrates
– Saturated (free brine) or dehydration
• Solubility, water content, pH
• Phase behaviour with glycols
• Transport properties
– Density, viscosity, speed of sound
• Frost/ dry Ice
• Interfacial Properties
• Mercury content
4 UKCCSRC Biannual, 2-3 April, Cambridge

5. Type of Fluids investigated
• From binary to multicomponent systems
5
Comp. MIX 1 MIX 2 MIX 3 MIX 4 MIX 5 MIX 6
CO2 95.64 89.83 69.99 49.93 95.97 69.99
Methane 0.6261 0 20.02 39.99 0 7.901
Ethane 0 0 6.612 3.510 0 7.015
Propane 0 0 2.58 1.530 0 4.968
n-Butane 0 0 0.3998 0.501 0 2.067
i-Butane 0 0 0.3997 0.499 0 2.049
n-Pentane 0 0 0 0.513 0 0
Nitrogen 1.41 5.05 0 3.524 2.028 6.009
Hydrogen 0.8175 0 0 0 0.605 0
Oxygen 0.08 3.07 0 0 0.783 0
Argon 1.21 2.05 0 0 0.611 0
CO 0.2127 0 0 0 0 0
Total 100 100 100 100 100 100
UKCCSRC Biannual, 2-3 April, Cambridge

6. Phase Equilibria – Vapour Liquid Equilibria
• Between CO2 and contaminant and between
contaminants
• Data needed for EoS model ----> Engineering
calculations
• Saturation pressure of “typical” CCS stream for
validation
6 UKCCSRC Biannual, 2-3 April, Cambridge

7. Why Measure VLE?
• Lack of data for components expected in CCS
stream -- > especially for toxic gases
7
CO2 CO N2 O2 Ar H2 NO CH4 C2H6 C3H8 NO2 SO2 H2S N2O
CO2
CO
N2
O2
Ar
H2
NO
CH4
C2H6
C3H8
NO2
SO2
H2S
UKCCSRC Biannual, 2-3 April, Cambridge

8. What we have covered so far
8
CO2 CO N2 O2 Ar H2 NO CH4 C2H6 C3H8 NO2 SO2 H2S N2O
CO2 NEW NEW NEW NEW NEW NEW
[19-
36]
[37 -
49]
[47,50-
61]
CD
[62-
64]+CD
NEW [141]
CO
[65-
70]+CD
CR [67]
[82-
83]
NEW
[79-
82]
[84-
85]
[84-88] ND NEW [89] NEW
N2
[90-
93]
[90]
[94-
97]
NEW DWA ND
[99-
109]
[100-
102]
NEW
O2 [90] ND ND CRYO CD
[107-
108]
ND
[106-
109]
ND
[104-
105]
Ar CRYO NEW CRYO [140] NEW ND NEW ND NEW
H2 ND
[110-
119]
[111-
112,
120]
[121-
123]
ND NEW ND ND
NO [124] ND ND [29] NEW ND ND
CH4 DWA ND [99]
[126-
131]
NEW
C2H6 DWA ND NEW
[132-
134]
NEW
C3H8 ND [125]
[136-
139]
NEW
NO2 CR ND ND
SO2 ND ND
H2S ND
N2O
UKCCSRC Biannual, 2-3 April, Cambridge

9. VLE Apparatus
9
Specifications
– Ti Rig – 200 ml
– Maximum working
pressure: 200 bar
– -30 °C < T < 120 °C
Accuracy
T : ± 0.1 °C
P: ± 0.05 bar
Phase samplings: ROLSI™
Schematic illustration of the cell
used for
VLE studies
Magnetic Motor
Temperature Probe
PressureTransducer
Capillary Sampler
2-wayvalve
Cooling Jacket
Cooling Fluid in/out
Equilibrium Cell
Window
UKCCSRC Biannual, 2-3 April, Cambridge

10. 0
1
2
3
4
5
6
7
0 0.2 0.4 0.6 0.8 1
P/MPa
x1, y1
Typical Experimental / Modelling Results
10
kij =0
Tuned kij
Vapour – Liquid Equilibria in the H2S + CO2 Binary System
0°C
-15°C
UKCCSRC Biannual, 2-3 April, Cambridge

11. Validation: Phase Envelope
11
Exp. and predicted Phase Envelope (Blue and Red Lines: PR-EoS with tuned kij;
Dotted lines: PR-EoS with kij=0).
UKCCSRC Biannual, 2-3 April, Cambridge

12. • Knowledge of the maximum allowable water content in CO2-
rich fluids is critical for a safe transport of CO2 to storage sites
– Hydrates, corrosion
• Limited data are available on the phase behavior of CO2 in
presence of hydrates
– GPA RR80 and RR99 (also published in SPE)
– Unfortunately the reliability of these studies has been recently
questioned in a few papers (ex BRE: Hendrick et al., 2010)
– Gap in data at low temperature (T<-20°C, Statoil: de Koeijer, 2010)
– Effect of contaminants not evaluated
12
Dehydration Requirement
UKCCSRC Biannual, 2-3 April, Cambridge

13. Dehydration – Lab Apparatus
13
-33.0 C
NITROGEN CYLINDER
CHILLED MIRROR HYGROMETER
T PROBE
P TRANSDUCER
FLOW METER
HEATED LINE
EdgeTech DewMaster :
- Can measure dew/frost
point from -75 to 100 °C
and up to 20 bar
- Resolution 0.1 °C
- Accuracy ±0.2 °C
UKCCSRC Biannual, 2-3 April, Cambridge

14. Apparatus: Schematic TDLAS Set-up
14 UKCCSRC Biannual, 2-3 April, Cambridge

15. Dehydration Requirement
• Typical Results for a saturated system (free water)
15
Exp. and predicted hydrate (sI) dissociation conditions for MIX 2
UKCCSRC Biannual, 2-3 April, Cambridge

16. Typical Experimental / Modelling Results
16
Water Content in pure CO2 and MIX 2 at 150 bar
UKCCSRC Biannual, 2-3 April, Cambridge
0
500
1000
1500
2000
2500
-50 -40 -30 -20 -10 0 10 20
yw/ppm
T/ °C
CO2 (Chilled Mirror)
CO2 (TDLAS)
MIX 2
10% impurities (no H2S or
SO2) ~ 20% reduction in
water content (to pure CO2)

17. Density / Viscosity – Exp. Equipment
17
A schematic view of the viscosity and density experiments setup
High temperature and
pressure oscillating U-tube
densitometer:
Anton Paar DMA-HPM
Cell:
Working Pressure:
Up to 20,000 psia (1400 bar)
Working Temperature:
-10 °C to 200 °C
Material:
U-shaped Hastelloy C-276 tube
Temperature Variation: ±0.01 °C
Oven:
BINDER GmbH
Working Temperature:
-70 °C to 200 °C
mPDS 2000V3
evaluation unit
UKCCSRC Biannual, 2-3 April, Cambridge

18. Viscosity Results
18
0
50
100
150
200
250
300
350
0 25 50 75 100 125 150
Viscosity,η/µPa.s
P / MPa
0
5
10
15
20
25
30
35
0 2 4 6 8 10
Viscosity,η/µPa.s
P / MPa
MIX 2 Viscosity – Modelling using modified CO2 1-fluid CSP model
(), T = 243.15 K (), T = 253.15 K (), T = 273.15 K (), T = 283.15 K
(), T = 298.15 K (), T = 323.15 K (), T = 373.15 K (), T = 423.15 K
UKCCSRC Biannual, 2-3 April, Cambridge

19. Density Results
19
MIX 2 Density – Modelling using modified EoS with CO2 volume correction
(), T = 273.26 K (), T = 283.31 K (), T = 298.39 K (), T = 323.48 K (), T = 373.54 K
(), T = 423.43 K
UKCCSRC Biannual, 2-3 April, Cambridge
0
250
500
750
1000
1250
0 25 50 75 100 125 150
Density,ρ/kg.m-3
P / MPa
0
10
20
30
40
50
60
70
80
90
100
110
1 2 3 4
Density,ρ/kg.m-3
P / MPa

20. Density
20
Density difference between pure CO2 and MIX 2 in the supercritical region (50°C)
-200
-150
-100
-50
0
0 25 50 75 100 125 150
ρ/kg.m-3
P / MPa
>35% reduction in density
UKCCSRC Biannual, 2-3 April, Cambridge

21. Frost Point/ Dry ice
• VSE of CO2-mixtures important issue
– safety assessment of CO2 pipelines
– possibility of solid or ‘dry ice’ discharge during an
accidental release or rapid decompression
• Removal of CO2
– A technique has been suggested based on frosting CO2 at
low temperature and separating the CO2 solid from natural
gas
• No data were found for systems of interest in CCS.
21 UKCCSRC Biannual, 2-3 April, Cambridge

22. Frost Point/ Dry ice - Equipment
22 UKCCSRC Biannual, 2-3 April, Cambridge
Cross-sectional view of the SETARAM BT 2.15
BT 2.15 Calorimeter
Internal Block

23. Frost Point/ Dry ice - Results
23 UKCCSRC Biannual, 2-3 April, Cambridge
Predicted (PR-EoS) and experimental phase diagram of CO2
1
10
100
1000
-80 -60 -40 -20 0
P/bar
T/ °C
Vapour
Liquid
Solid
Ttr=-56.76 ± 0.1°C
Ptr=5.12 ± 0.005 bar
Span and Wagner
Tt=-56.558 °C and
Pt= 5.1795 bar

24. Frost Point/ Dry ice - Results
24 UKCCSRC Biannual, 2-3 April, Cambridge
0
20
40
60
80
100
120
140
160
180
200
-75 -55 -35 -15 5 25
P/bar
T / °C
Calorimeter measurements
Isochoric measurements
Bubble points
Experimental and predicted frost points of MIX 2

25. Other Properties
• CO2 solubility in brine and water in CO2
– Effect of impurities, water chemistry
– Halite formation
– IFT
• CO2 – Glycols/aqueous glycol solution phase
equilibria, i.e. Optimisation of glycol
dehydration
• Calorific properties (heat capacity)
• Mercury
25

26. Conclusions
• Filling the knowledge gaps
• Practical implementations of results (parameters,
tuned EoS)/models in a modelling package
26

27. Conclusions
• New/unique range of experimental data
– VLE for toxic gases
– Hydrates in low water content (dehydration)
– Transport Properties....
– Frost Point
• Phase II of the project starting in October
2014
27

28. Acknowledgements
28

29. 2929
Thank you
for your attention
Questions?