Carbon Dioxide

Dr. Reid B. Grigg

New Mexico Petroleum Recovery Research CenterNew Mexico Institute of Mining and Technology

Socorro, New Mexico

CO2 has been receiving a lot of publicity as of late, mostly bad PR.

Let’s get to know this compound better.

CO2 is a vital compound for natural processes, but can create havoc with nature as well.

The following will be covered briefly:

Properties/Phase Behavior

Solubility/Extraction

Swelling

Density

Viscosity

CO2 Sequestration Volume Estimates

Properties of Carbon Dioxide

Molecular Weight = 44.01 g/molCritical Pressure = 1071 psia (7.38 MPa)Critical Temperature = 87.9 F (31.1 C)Critical Density = 0.469 g/cc

P-T Phase Diagram for Carbon Dioxide (Wikipedia)

Critical point

P-T Phase Diagram for Carbon Dioxide (Wikipedia)

Critical point

Where we live

P-T Phase Diagram for Carbon Dioxide (Wikipedia)

Critical point

Where we live

World of geologicSequestration

D-P Phase Diagram for Carbon Dioxide (Wikipedia)

Critical point

P-T Phase Diagram for Carbon Dioxide (Wikipedia)

Critical point

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Pres

sure

[psi

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0.10.20.30.40.50.60.70.80.85phase change

Gas

Liquid

Supercritical

Critical point

Constant density [g/cm3] indicated

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0.10.20.30.40.50.60.70.80.85phase change

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Liquid

Supercritical

Critical point

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sure

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0.10.20.30.40.50.60.70.80.85phase change

Gas

Liquid

Supercritical

Critical point

Constant density [g/cm3] indicated

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30 50 70 90 110 130 150 170 190Temperature [F]

Pres

sure

[psi

a] .

0.10.20.30.40.50.60.70.80.85phase change

Gas

Liquid

Supercritical

Critical point

Constant density [g/cm3] indicated

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Temperature [F]

Pres

sure

[psi

a] .

0.10.20.30.40.50.60.70.80.85phase change

Gas

Liquid

Supercritical

Critical point

Constant density [g/cm3] indicated

800

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70 75 80 85 90 95 100

Temperature [F]

Pres

sure

[psi

a] .

0.10.20.30.40.50.60.70.80.85phase change

Gas

Liquid

Supercritical

Critical point

Constant density [g/cm3] indicated

CO2 density versus pressure at temperatures from 40-140 F

Effects of density/volume/phase changes

Injection Production Facilities

Pipelines Compressors Booster pumps Etc

Three phases in CO2/oil micromodel tests.

Properties/Phase Behavior

Solubility/Extraction

Swelling

Density

Viscosity CO2 Sequestration Volume

Estimates

Equilibrium Constant

Ki = yi

-------- xi

For a two phase vapor/liquid systemyi = mole fraction of component i in the vapor phasexi = mole fraction of component i in the liquid phase

Water-CO2 Density

Properties/Phase Behavior

Solubility/Extraction

Swelling

Density

Viscosity CO2 Sequestration Volume

Estimates

Oil-CO2 Density

Properties/Phase Behavior

Solubility/Extraction

Swelling

Density

Viscosity CO2 Sequestration Volume

Estimates

Oil-CO2 Density

Oil-CO2 Density

Oil-CO2 Density

Oil-CO2 Density

Water-CO2 Density

Properties/Phase Behavior

Solubility/Extraction

Swelling

Density

Viscosity CO2 Sequestration Volume

Estimates

Properties/Phase Behavior

Solubility/Extraction

Swelling

Density

Viscosity CO2 Sequestration Volume

Estimates

Volume Estimates• 88 Permian Basin reservoirs have a

total pore volume of about 10 x109 m3 (61 billion barrels).

• Using a conservative displacement efficiency and CO2 retention, 12% of the pore volume (1.2 x 109 m3) estimated for potential CO2 storage or ~ 1 x 109 tonnes).

• ~1 x 109 tonnes possible storage.

CH2 +(1.5)O2 = CO2 + H2OOil (~44/14 = 3.14)

CH4 +(2)O2 = CO2 + (2)H2OMethane (44/16 = 2.75)

CH +(1.25)O2 = CO2 + (0.5)H2OCoal (~44/13 = 3.38)

Production of CO2 from Hydrocarbons (Mole Wt. CO2/Mole Wt. Hydrocarbon)

For example if the worldwide oil production is 12 x 106 m3/d

(15 x 106 m3/d [5.5 x 109 m3/yr] reservoir volume assuming a FVF of 1.25)

Assume density of hydrocarbon = 800 kg/m3

(specific gravity of 0.8)

Crude production ~ 4.4 x 109 tonnes/yr)

CO2 production ~ 13.8 x 109 tonnes/yr(thus 1 billon tonnes storage is ~ one month of world

production)

Conclusions Being a Supercritical fluid in and of itself is not necessarily significant.

Many of the properties of CO2 are dependent on temperature and pressure. The most significant property is the density of CO2.

Understand the different properties of CO2

and then you can predict what will happen under your system conditions.

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CO2 methane ethane

Gas

SC

F of

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@ S

TP/B

BL

H2O

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Temperature [C]

Pres

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0.10.20.30.40.50.60.70.80.85phase change

GAS

Liquid

Super-Critical

Temperature

- T -(oC)

Density- ρ -(kg/m3)

Liquid Specific Heat Capacity- cp -(kJ/kg K)

Temperature- T -(C)

Gas Specific heat capacity- cp -(kJ/kgK)

-50 1156 1.84

-40 1118 1.88 -73 0.735

-30 1077 1.97 -48 0.763

-20 1032 2.05 -23 0.791

-10 983 2.18 2 0.819

0 927 2.47 27 0.846

10 860 3.14 84 0.871

20 773 5.0

30 598 36.4

Carbon Dioxide specific heat capacity for liquid and gas. (Joule-Thomson effect).