Page 207 - Chemical and process design handbook

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CARBON DIOXIDE

Carbon dioxide (CO , melting point: –56.6°C at 76 psi – 527 kPa, density:
2
1.9769 gL at 0°C) is a colorless, odorless gas. Solid carbon dioxide sub-
limes at –79°C (critical pressure: 1073 psi, 7397 kPa, critical temperature:
31°C). High concentrations of the gas do cause stupefaction and suffoca-
tion because of the displacement of ample oxygen for breathing. Carbon
dioxide is soluble in water (approximately 1 volume carbon dioxide in 1
volume water at 15°C), soluble in alcohol, and is rapidly absorbed by most
alkaline solutions.
Carbon dioxide is made by steam-reforming hydrocarbons (Fig. 1), and
much of the time natural gas is the feedstock.
CH + 2H O → 4H + CO
4 2 2 2

Carbon dioxide
free gas

Permangate scrubber Compression

Flue gas scrubber Flue gas scrubber Absorber Reactivator
and cooling

Natural gas
Dehydrator

Liquid Solid
carbon carbon
dioxide dioxide
FIGURE 1 Manufacture of carbon dioxide.

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