Page 401 - Air pollution and greenhouse gases from basic concepts to engineering applications for air emission control

380 12 Carbon Capture and Storage

The average speed in the pipe can be determined using

4 _ m 4 111
U ¼ ¼ ¼ 1:007 m=s
qpd 2 877 p 0:4 2
The corresponding Reynolds number is determined using Eq. (12.63).

4 _ m 4 111 6
Re ¼ ¼ ¼ 4:57 10
lpd 7:73 10 5 p 0:4
6
With e ¼ 4:6 10 5 m, d ¼ 0:4 m and Re ¼ 4:57 10 , the Darcy friction factor
can be determined using Eq. (12.62) as follows:

!
1 e 2:51

f D 2 ¼ 2 log 10 þ 1
3:7d 2
Ref
D
!
4:6 10 5 2:51
¼ 2 log þ
10 1
3:7 0:4 6 2
4:57 10 f D
!
5:492 10 5
¼ 2 log 10 3:108 10 5 þ 1
f 2
D
By iteration, we can get f ¼ 0:0217.
D
Then we can calculate the pressure drop over 100 km distance length using
Eq. (12.61).
2
qU
DP ¼ f D DL
2d
2
877 1:007 3 6
¼ 0:0217 100 10 ¼ 2:41 10 Pa
2 0:4
So the pressure drop is about 2.41 MPa over a distance of 100 km. Due to this kind
of great resistance, intermediate pumping (or booster) stations are required at cer-
tain intervals along the pipeline.
We have to be careful that the CO 2 properties are assumed constant in the above
example in order to simplify the calculation. In reality, they cannot remain constant.
Glilgen et al. [25] experimentally determined the pressure, density, and temperature
relationship of CO 2 in the homogeneous region for pressures up to 13 MPa and
temperatures in the range of 220–360 K. For P < 9 MPa and T > 298 K, CO 2
density varies considerably with P and T.
In the engineering practice, it is critical to ensure enough pressure to maintain
above vapor–liquid equilibrium conditions to avoid liquid slugs and other opera-
tional problems resulted from a two-phase (gas–liquid) flow. A typical operating