Chemical reactors - reaction

[atsum]

PER - chemical reaction

Q: A reactor is needed to convert A to R in a liquid reaction. The stoichiomentry is simply A→R and the rate data is given in the table below (P5.21, Levenspiel 1999).

For the reactant concentration to drop from CA0 = 1.3 mol/L to CAf =0.3 mol/L, determine,

a) the time required with a batch reactor. (ans: 10.21 min).

b) the volume required for a flow reactor to achieve the same conversion as in (a) and at
a feeding rate of A 1000 mol/h in (1) a PFR, and (2) a CSTR. (ans: PFR V= 130.8 L;
CSTR V = 25.6 L).

c) the volumes of two flow reactors in series with the exit concentration of A from the 1st
reactor xA1= 0.231 (i.e. CA1= 1 mol/L) for (1) 1st PFR +2nd CSTR, and (2) 1st CSTR
+2nd PFR. For both cases, sketch the area for each reactor in the 1/rA-xA plot. (ans: 1,
V1= 38.7 L,V2 17.9 L; 2, V1= 77.0 L, V2 = 85.4 L).

Hints: Plot 1/rA vs. xA, calculate the area under the line, either by measuring the graphical
area or by integration of the trend line equation (which should be a 5th order polynomial).

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This time, I cannot solve question (C).

I can only calculate the part of CSTR.

For the PER in case (1):

(1000/60)(5.0244) (5.0244 is the area that from xA=0 to 0.230769, 1000/60 is the flow rate from part (B))
=83.74L

My answer is wrong, but I don't know what's wrong with my calculation

 

[danago]

Are you sure about your data? I have the same textbook, and mine says 0.045 and 0.042 for the last two values of r

 

[atsum]

Oh, thank you for reminding me. because I don't have the textbook.
But, I still cannot find out the answer after using the right value.
Is it wrong for me to plot a graph?

 

[danago]

I don't think there is anything wrong with fitting the data to a line and then integrating from 0.3 to 1.3 (which is one method that the hint does suggest), however i think it would be easier to just integrate numerically with approximating sums. Keep in mind that different methods will give different answers (my solution manual says 12.75 minutes).

 

[LudusRex]

.

A: Chemical reactors are essential for carrying out chemical reactions in a controlled and efficient manner. In this case, the reaction being investigated is the conversion of A to R in a liquid reaction. The stoichiometry of the reaction is simply A→R, and the rate data has been provided in a table. Based on this information, the following questions have been posed:

a) The time required for the reactant concentration to drop from CA0 = 1.3 mol/L to CAf =0.3 mol/L in a batch reactor is 10.21 minutes. This can be calculated by using the batch reactor design equation and solving for time.

b) In order to achieve the same conversion as in part (a) and with a feeding rate of A 1000 mol/h, the required volumes for a flow reactor are: PFR V= 130.8 L and CSTR V = 25.6 L. These can be calculated using the design equations for a PFR and CSTR.

c) In order to achieve an exit concentration of A from the first reactor of xA1= 0.231 (i.e. CA1= 1 mol/L), two flow reactors in series are needed. For the first case (1st PFR + 2nd CSTR), the required volumes are: V1= 38.7 L and V2= 17.9 L. For the second case (1st CSTR + 2nd PFR), the required volumes are: V1= 77.0 L and V2= 85.4 L. These can be calculated by plotting 1/rA vs. xA and calculating the area under the line, either graphically or through integration.

It is important to check your calculations and make sure you are using the correct equations and data. If your answers are different from the provided solutions, you may have made a mistake in your calculations. Additionally, make sure you are using the correct units and converting as necessary. If you are still unsure, it may be helpful to consult with a colleague or reference materials for clarification.