Introduction to Carbon Capture - Introduction to Carbon Capture and Sequestration - page 161

4.2 Parasitic energy
1. In the graph below the minimum work for separating CO 2 is given
as a function of the mole fraction of CO 2 . Identify the correspond-
ing processes of CO 2 separation given by the letters A-D.

20

A

15

10

B

C

5

D

0

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

Mole fraction of CO 2

2. The energy penalty of separating CO 2 at a temperature T is
given by the red curve. Now when we decrease the temperature,
the blue curve gives the energy penalty at this temperature.
Which one is correct?

6.5%

a.

6.5%

b.

6.0%

6.0%

13% CO 2

5.5%

13% CO 2

5.5%

5.0%

5.0%

4.5%

4.5%

4.0% 4.0%

3.5% 3.5%

3.0%

3.0%

80% 84% 88% 92% 96% 100%

80% 84% 88% 92% 96% 100%

Percent of CO 2 captured

Percent of CO 2 captured

c.

6.5%

6.0%

13% CO 2

5.5%

5.0%

4.5%

4.0%

3.5%

3.0%

80% 84% 88% 92% 96% 100%

Percent of CO 2 captured