Absorption - Introduction to Carbon Capture and Sequestration - page 226

Section 9
Review

5.1. Reading self-test

1. Which statement about effi ciency of an absorber is correct?
a. If we use an infi nite number of plates, the thermodynamic
losses are close to zero
b. Countercurrent fl ow is less effi cient compared to concurrent
fl ow in an absorber
c. Plates are essential in an absorber to increase the contact
area between the liquid and gas

2. Which statement about the equilibrium line is not correct?
a. The smaller the slope, the better the solvent
b. Only at low concentration is the equilibrium line a straight line
c. If the system does not reach perfect equilibrium, the actual
concentration in the solvent is lower compared to the equi-
librium concentration

3. Henry's law is typically used at low partial pressures. Why?
a. At high pressure, the gas does not behave like an ideal gas
b. At high pressure, the number of dissolved gas molecules can
become so large that the molecules will infl uence each other
c. At high pressure, the molecules cannot escape from the liq-
uid phase
d. At high pressure, the liquid is not ideal
e. Answers A and B
f. Answers A, B, C and D

4. Which statement about the operating line is not correct?
a. The slope of the operating line increases if we increase the
amount of absorbent in the process
b. All operating lines have in common the point (x reg

CO 2 , y exh

CO 2 )
c. The operating line gives the relation between the concentra-
tion of the fl uid and the gas leaving plate P