A quantity of 10,000 kmol of a chemical B is produced industrially in a manufact
ID: 952248 • Letter: A
Question
A quantity of 10,000 kmol of a chemical B is produced industrially in a manufacturing campaign running for quarter of a year (total operating time 1800 h) in an isothermal batch reactor, according to the liquid phase 1st order isomerisation A rightarrow B with reaction rate constant k_1 = 0.1439 h^-1 which takes place in a solution with initial concentration of reactant A equal to C_A0 = 1 kmol m^-3. At the end of each batch reaction run, it takes 2 h to empty, clean, maintain and refill the reactor. The conversion in each batch is X_A = 90 %. Calculate the reaction time for each batch. Determine the reactor volume required. Solve the above problem when A rightarrow B is a second order reaction with reaction rate constant k_2= 0.5 m^3 h^-1 kmol m^-3, X_Ao = 90% Calculate the reaction time for each batch. Determine the reactor volume required.Explanation / Answer
for first order reaction -ln(1-XA)= Kt
where XA = conversion =0.9 and t= time and K= rate constant=0.1439/hr
-ln(1-0.9)= 0.1439*t
t=16 hrs
time requires for emptying, operation and maintenance= 2hr
Total time =16+2= 18hr
number of hrs= 1800 hr
Number of batches= 1800/18= 100 batches
Moles of reactant to be added per batch= 10,000/100= 100 kmol
CAO= 1kmol/m3
Volume= 100/1=100m3
b) for the second case of second order
XA/(1-XA)= Kt
0.9/0.1= 0.5*t
9/0.5= t
t= 18 hrs
Shut down and maintenance time =2 hrs
total time per batch= 18+2=20 hrs
Number of batches=1800/20= 90
Batch capacity = 10000/90= 111.11 Kmol
Volume = 111.1/1= 111.1 m3