Residence Time Distribution

Question 1

What is the definiation of residence Time ditribution (RTD)

Answer 1

it the time spent by a fluid elemnet in the vessel

Question 2

What does the RDT enables us?

Answer 2

it enables traceability, develop control stragtegies

Question 3

what are the two types of flow patterns?

Answer 3

plug flow and mixed flow

Question 4

Why do we like this flow patterns?

Answer 4

1. one or the other often is optimum no matter what we are designing for
2. these two patterns are simple to treat

Question 5

How do we account for the real equipment which deviates from these ideals flow pattern?

Answer 5

by using the interrelated factots such as RTD, state of affregation and earliness and latness of mixing

Question 6

What are the reason for the deviation from the two ideal flow patterns?

Answer 6

1. Channeling of flui
2. Recycling of fluid
3. by creation of stagnent region sin the vessel

Question 7

Definition of exit age distribution E?

Answer 7

it reflexs the time of the fluid passing through the vessel, since fluid could tak different routes through the reactor

Question 8

what is the unit of E

Answer 8

1/t

Question 9

How can we present E in such a way that the curve is unity? (Know how to write the equation)

Answer 9

By normalizing the distribution

Question 10

What is the one restriction of the E curve?

Answer 10

that the fluid only enters and only leaves the vessel one time

Question 11

what is the meaning of that restriction on the E curve

Answer 11

that there should be no flow or diffusion or upflow eddies at the entrance or at the vessel exit

Question 12

How is the restriction condition called?

Answer 12

closed vesel boundary condition

Question 13

what is a open vessel boundary?

Answer 13

where elements of fluid can cross the vessel boundary more than one time

Question 14

What does the open vessel represent?

Answer 14

the fraction of exit stream of age between t and t+ dt

Question 15

What is the formel for the fraction?

Answer 15

E dt [-]

Question 16

what does the term “age” means?

Answer 16

for an element of th exit stream refers to the time spent by that elemnt in th vessel

Question 17

How does the exit age distribution curve E looks like?

Answer 17

Do you know how to draw it?

Question 18

What is the formel for the fraction younger than age t(1)

Answer 18

Do you know it?

Question 19

What is the formel for the fraction older than age t(1)

Answer 19

Do you know it?

Question 20

After the normalization process, what is the value of the AUC?

Answer 20

one

Question 21

on what does the value on the x-aches depends on?

Answer 21

on the amount of concentration used

the tracer

Question 22

what are the different ways to study the flow pattern in vessels?

Answer 22

pulse, step, periodic and random input

Question 23

How do you fine E curve from the C(puls) curve?

Answer 23

by simply change the concentration scale such that the area under the curve is unity

Question 24

what are the useful information obtainable from the puls trace experiment? (know how to draw the curve)

Answer 24

1. instantaneously introduce M units of tracer into the fluid entering the vessel
   Record the leaving traces
   Evalute the area under the curve
   Evalution the mean