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[XBOX999]

Hello, I am first year student.This is my first course in Chemical engineering.I have midtearm ommorow.Can you tell me the way how to solve this problem please.

The production of butadiene (C4H6) by the oxy-dehydrogenation of butenes (C4H8) in the presence of a catalyst occurs according to the following gas phase reactions:
C4H8+0.5 O2 ----> C4H6 +H2O
C4H8 + 6O2------> 4 CO2+4H2O
The feed, consisting of a mixture of butenes, water vapour, air and a small quantity of butadiene, is added to the recycle stream and fed to the reactor. The gases exiting from the reactor are cooled in heat exchangers and condensed water is removed using a decanter. One can assume that all of the water is condensed. The carbon dioxide and nitrogen in the air are then completely eliminated in an oil wash tower.
The butadiene is separated from the butenes using a furfuryl alcohol extraction tower. A small proportion of unreacted butadiene and butenes are recycled.
Below is some additional information about the process:
1. The fresh feed is composed of 10 000 kmol/h water, 3 500 kmol/h air, 645 kmol/h butenes and 58 kmol/h butadiene.
2. The production of butadiene is 628 kmol/h.
3. The mean value of the butadiene/butenes molar ratio obtained by chemical analysis in the recycle stream is 0.027586 and after the mixing point (at the reactor entrance) is 0.064814.
4. The oxygen in the air is completely consumed by the reactions.

Calculate the overall flowrate and the flowrates for each species (see the figure below) using the extent of reaction.
Complete the following table.
the table and the graph is in the attachment

Attached Files

•  the table and the graph.pdf   100.14KB   8 downloads

Edited by XBOX999, 17 March 2010 - 11:56 PM.

[Art Montemayor]

Xbox:

This is now tomorrow and you have already have had to get out of bed and confront your midterm exam. I hope you had better luck in the exam than the responses that you have received in this thread.

More than anything, I hope that you have learned and embraced several important issues from this experience - lessons that you can profit from in your future as a Chemical Engineering Student (if you succeed in remaining as a competing Ch E. student in your university).

• The first lesson is to recognize when you are in deep trouble, and immediately resort to asking for or seeking help from your professors or other sources.
• The next lesson is to not allow yourself the luxury of getting into trouble in the first place: simply pay attention in each class theory session and take bountiful notes. Study these notes and work all the example problems that you can on a DAILY BASIS.
• Make sure that you meet all homework and assignment deadlines and that you do all of your work in a detailed, documented method (preferably in spreadsheets) and that you get feedback from your supervisor or professor.
• Stay aware of what is going on in your course of study by reading and studying all your textbooks AHEAD of the day the subject matter is being lectured. DO NOT ALLOW YOURSELF TO GET BEHIND IN YOUR SUBJECT MATTER OR ASSIGNMENTS (as you have recently done with this problem).

If you have hopes and desires of graduating as a Chemical Engineer, do not allow yourself the situation of having to prepare for a major exam with only a few days to prepare for it - much less ONLY ONE DAY, as is the case here. If you continue on this path you will never graduate as an engineer.


Good Luck.