a & c

P4-8y Troubleshooting (a) A liquid-phase isomerization AB 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 reac- tion 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%. Suggest reasons for the discrepancy and suggest something that would give closer agreement between the pre- dicted and measured conversions. Back your suggestions with calcula. tions. P.S. It was raining that day, (b) The first-order gas.phase isonierization reaction A B with k = 5 min! is to be carried out in a tubular reactor. For a feed of pure A of 5 dmYminthe expected conversion in a PFR is 63.2%. However, when the reactor was put in operation, the conversion was only 58.6%. We should note that the straight tubular reactor would not fit in the available space. One engineer suggested that the reactor be cut in half and the two reac- fors he put side by side with equal feed to each. However, the chief engi- neer overrode this suggestion saying the tubular reactor had to be one piece so he bent the reactor in a U shape. The bend was not a good one. Brainstorm and make a list of things that could cause this off-design specification. Choose the most logical explanation/modeland carry out a calculation to show quantitatively that with your model the conversion is 58.6%. (An Ans: 57% of the total) (c) The liquid-phase reaction AB was carried out in a CSTR. For an entering concentration of 2 nvol/dmr'. the conversion was 40%. For the same reactor volume and entering con- ditions as the CSTR. the expected PFR conversion is 48.6%. However, the PFR conversion was amazingly 50% exactly. Brainstorm reasons for the disparity. Quantitatively show how these conversions cane about fie, the expected conversion and the actual conversion)