Question

A liquid-phase isomerization is carried out in a 1000-gal CSTR that has a single impeller located halfway down the reactor. The liquid enters at the top of the reactor and exits at the bottom. The reaction is second order. Experimental data taken in a batch reactor predicted the CSTR conversion should be 50%. However, the conversion measured in the actual CSTR was 57%.
A) Suggest reasons for the discrepancy and suggest something, e.g., a model, that would give closer agreement between the predicted and measured conversions. Back your suggestions with calculations. P.S. It was raining very hard that day.

Answer 1

Answer:

The conversion achieved for the first CSTR impeller is 0.382

Discrepancy = 0.188

Explanation:

The impeller divides the CSTR into 2 equal reactors of volume 500gal

Using V = FaoX/ (-ra)

500gal = Fao×Xa/[(KCao^2( 1 -X1)^2]

500gal = CaoVoX1/ KCao^2(1-X1)

500gal= 500gal × X1'/(1 - X1)^2

(1 -X1)^2 = X1

X1^2 - 3X1 + 1 = 0

X1= 0.382

Conversion achieved in the first CSTR is 0.382

Actual measured CSTR = 57% =57/100=0.57

Discrepancy in the conversions= 0.57 -0.383 =0.188