Liquid A-->B in 1000-gal CSTR with a single impeller halfway down the reactor. E

Question

Liquid A-->B in 1000-gal CSTR with a single impeller halfway down the reactor. Experimental data taken in a batch reactor predicted the CSTR conversion should be 50%. However, the conversion measured in the actual CSTR was 57% How/why is this possible? How could you explain this with a calculation?

Explanation / Answer

P4-88 troubleshooting (a) A liquid-phase isomerization A---> B 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 hatch reactor predicted the CSTR conversjon should be 50%. However, the conversion measured in the actual CSTR was 57%. Suggest reasons for the discrepancy and suggest something that wouid give closer agreement between the predicted and measured conversions. Back your suggestions with calculatioos. p.S. It was raining that day. (b) The first-order gas-phase isornerization reaction k A----> B with k = 5 min-1 is to be carried out in a tubular reactor. For a feed of pure A of 5 drn^3/min. the 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 reactors he put side by side with equal feed to each. However. the chief engineer 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. Chaose the most logical explanation/model, and 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 A---->B was carried out in a CSTR. For an entering concentration of 2 rnol/dm3. the conversion was 40%. For the qame reactor volume and entering conditions as the CSTR, the expected PFR conversion is 48.6%. However. the PFR conversion was amazingly 50% exactly. Bninqtonn reasons for the disparity. Quantitatively show how these conversions came about (i.e., the expected conversion and the actual conversion). (d) The pas-phase reaction A + B ----> C+D is carried out in a packed bed reactor. When the panicle size was decreased hy 15%. the conversion remained unchanged. When the particle size was decreased by 20%. the conveaion drcreaced. When the original particle size was increaced by 15%, the conversion also decreased. In all cases the temperature, the total catalyst weight. and all other conditions remained unchanged. What's going on here?

Related Questions

Navigate

• Browse (All)
• Browse L
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.