Separation Processes Questions and Answers - Kremser Group Method

1. If the :
Component distillate rate for LK (di) = 60
Component distillate rate for HK (dj) = 10
Bottom flow rate for LK (bi) = 30
Bottom flow rate for HK (bj) = 10
Mean relative volatility is 2
What is the minimum number of stages required?
a) 1
b) 2
c) 3
d) 4

Answer: d
Explanation:Only 4 stages are required here.

2. If the :
Component distillate rate for LK (di) = 90
Component distillate rate for HK (dj) = 20
Bottom flow rate for LK (bi) = 30
Bottom flow rate for HK (bj) = 10
Mean relative volatility is 2
What is the minimum number of stages required?
a) 1
b) 2
c) 3
d) 4

Answer: d
Explanation: Only 4 stages are required here.

3. If the :
Component distillate rate for LK (di) = 50
Component distillate rate for HK (dj) = 10
Bottom flow rate for LK (bi) = 20
Bottom flow rate for HK (bj) = 10
Mean relative volatility is 2
What is the minimum number of stages required?
a) 1
b) 2
c) 3
d) 4

Answer: c
Explanation: Only 3 stages are required here.

4. Many separators are cascades where two contacting phases flow __________
a) Co-currently
b) Counter-currently
c) Same direction
d) In any direction

Answer:b
Explanation: Most of the cascades have contacting liquids flowing counter-currently.

5. Why the approximate calculations of composition of input and output field are called group methods?
a) Because they are found only in groups
b) Because only input-output group is there
c) Because they deal only with input-output calculation and don’t consider what exactly happens
d) It’s just a name

Answer: c
Explanation:The approximate calculations of composition of input and output field are called group methods because they deal only with input-output calculation and don’t consider what exactly happens.

6. If KD = 2, amount of solvent (V)= 100kg and amount of feed liquid is 300, what is the extraction factor?
a) 0.67
b) 1
c) 2
d) 3

Answer: a
Explanation: Since E= KDV/L, 2*100/300=0.67.

7. If KD = 2, amount of solvent (V)= 200kg and amount of feed liquid is 300, what is the extraction factor?
a) 0.67
b) 1.3
c) 2.4
d) 3

Answer: b
Explanation: Since E= KDV/L, 2*200/300=1.33.

8. If KD = 0.5, amount of solvent (V)= 100kg and amount of feed liquid is 300, what is the extraction factor?
a) 0.67
b) 1
c) 0.167
d) 3

Answer: c
Explanation: Since E= KDV/L, 0.5*100/300=0.167.

9. If KD = 2, amount of solvent (V)= 100kg and amount of feed liquid is 100, what is the extraction factor?
a) 0.67
b) 1
c) 2
d) 3

Answer: c
Explanation:Since E= KDV/L, 2*100/100=2.

10. If KD = 0.5, amount of solvent (V)= 500kg and amount of feed liquid is 300, what is the extraction factor?
a) 0.67
b) 1.33
c) 2
d) 0.833

Answer: d
Explanation:Since E= KDV/L, 0.5*500/300=0.833.