Vapour-Liquid and Solid-Vapour-Liquid Equilibria of the System (CO2 + H2) at

Temperatures Between (218 and 303) K and at Pressures up to 15 MPa

David Vega-Maza University of Aberdeen

Martin Trusler Niall R McGlashan

Imperial College London

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2

Scope

Impact of Phase behaviour

Apparatus

VLE results

SVLE results

Conclusions

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Scope

Post-combustion capture.

Oxy-combustion capture

Pre-combustion capture Natural gas reforming Coal gasification Integrated Gasification Combined Cycle

Ca looping

Chemical looping

Adsorption

• Physical Absorbents • Membranes • Cryogenic Separation

SEPARATION

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Scope

Pre-combustion CO2 capture offers an attractive route

to decarbonising coal-fired electricity production

Low-temperature physical separation of the CO2 may

offer significant cost savings compared with traditional

amine-based absorption processes

Costain’s Next Generation Capture Technology (NGCT)

concept embodies these ideas in a practical process

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Scope

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Impact of Phase behaviour

NGCT process modelling requires precise VLE data for

CO2-rich synthesis gas at low temperatures and high

pressures

Also require SVLE data to determine the lower

operating temperature locus to avoid solids formation

VLE of CO2 + H2 + impurities moderately well known

but much of the data are old and there are some

significant gaps – hence this new study

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Apparatus

Static apparatus with on-line sampling and GC analysis

Ranges: 193 ≤ T/K ≤ 473 and 0.5 ≤ p/MPa ≤ 20

Absolute calibration with pure gases by means of internal

GSV with sample loops under temperature and pressure

control

Process safety considered carefully

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Apparatus

Static apparatus with on-line sampling and GC analysis

Ranges: 193 ≤ T/K ≤ 473 and 0.5 ≤ p/MPa ≤ 20

Absolute calibration with pure gases by means of internal

GSV with sample loops under temperature and pressure

control

Process safety considered carefully

9

Apparatus

10

Apparatus

11

Apparatus

193 K < T < 473 K

p < 20 MPa

V = 0.14 dm3

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VLE results

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p-x-y diagram on H2 + CO2 system at -55 ⁰C, where x represents the molar composition of H2 in the liquid phase and y represents the molar composition of H2 in the vapour phase. Symbols: y -this work-; x –this work-; Tsang et al. [1] ; Spano et al. [2] 1. C.Y. Tsang, W.B. Streett. Chem. Eng. Sci. 36 (1981) 993-1000 2. J.O. Spano, C.K. Heck, P.L. Barrick. J. Chem. Eng. Data 13 (2)

(1968) 168-171

p-x diagram on H2 + CO2 system at -55 ⁰C, where x represents the molar composition of H2 in the liquid. Symbols: x –this work-; – – Tsang et al. [1] ; – – Spano et al. [2] 1. C.Y. Tsang, W.B. Streett. Chem. Eng. Sci. 36 (1981) 993-1000 2. J.O. Spano, C.K. Heck, P.L. Barrick. J. Chem. Eng. Data 13 (2)

(1968) 168-171

0

40

80

120

160

0 0.2 0.4 0.6 0.8 1

p/ b

ar

x or y

0

40

80

120

160

0 0.01 0.02 0.03 0.04

p/ b

ar

x

VLE results

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VLE results

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SVLE results

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SVLE results

SVLE locus determined from p-T behaviour during

cooling ramps

Allowance for sub-cooling prior to freezing

SVLE locus modelled with EoS for pure solid CO2 +

GERG-2008 EoS for (CO2 + H2) in the gas phase, evaluated

at the experimental temperature and vapour-phase

composition

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Conclusions

VLE and SVLE data measured for (CO2 + H2)

VLE results in good agreement with the available

Elementary modelling completed; GERG-2008 mixture

model planned for CO2 with impurities

Further measurement on (CO2 + CO), (CO2 + CH4) and

(CO2 + H2 + 100 ppm H2S)

Acknowledgement We are pleased to acknowledge financial support for this work provided by Costain Energy & Process and the Energy Technology Institute

VLE and SVLE of the System (CO2 + H2) at Temperatures Between (218 and 303) K and

at Pressures up to 15 MPa

Thank You David Vega-Maza University of Aberdeen

Martin Trusler Niall R McGlashan

Imperial College London

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