Posted on 5/13/2008
250 Exam location
Just a reminder - the final exam is in Room 1610 Engineering Hall. It is one of the big lecture halls on the first floor. See you at 2:45!
Posted on 5/9/2008
CBE 250 final exam questions
I'll be available in my office MONDAY from 8:30 to 10 AM and Tuesday from 11-12:30 for any last minute questions. Feel free also to email me or post questions to the forum. Just a reminder that Liz will be holding office hours on Sunday and on Monday afternoon.
Posted on 5/6/2008
Comments on 250 project
1. Watch your units on calculating the capital cost of the conventional process - the styrene flow rate to enter into the formula is in lb/yr. There are 2200 lb in one metric ton. MTA means metric tons per annum (latin for "each year").
2. Don't spend too much time on the conventional process! You should be able to quickly get a rough estimate of raw material costs and energy costs (from overall energy balance, considering the enthalpy of reaction) and the capital costs (from the equation given in the project update).
3. You need to identify what you will do with each stream leaving your process (other than the styrene) - it could go to waste, to combustion, to another process as a raw material, etc. You can give yourself 'credit' for its use as a fuel or raw material. If you are dumping something to wastewater, a reasonable estimate of the cost of processing the wastewater is $0.40 per kg of organic treated. (Organic would be methanol, toluene, styrene, etc.).
4. If you find that recycling is causing you problems in completing material balances, especially in dealing with trace quantities of materials, (e.g., what if you are recycling toluene and it has a little bit of ethylbenzene in it), just ignore the trace quantities in your material balances and make a note of it in your report that a more accurate analysis is needed in the future. Something 1% or less we'll agree is "trace". If its just a bit more than that, let's discuss.
5. Energy integration should be done after you are happy with the basic flowsheet. It's ok if you don't get to this step, but you should calculate where you will need heat sources and sinks, and the quantities, temperature, and values of each. You can credit yourself with any excess Q that leaves the plant (for example, if you combust something and make high pressure stream, give yourself a credit for the energy content of the steam that you "sell".) It would be good to identify opportunities for matching heat sources and sinks. If you are able to get to actually doing the heat integration, even better.
6. Don't prepare a formal presentation, but on Thursday you should be prepared to give (a) raw material cost estimates ($yr), (b) energy costs ($/yr), (c) capital cost estimate ($) for the new process, as well as a recommendation about whether you think its better than the conventional process. You should also be prepared to sketch out your flow diagram on the board and explain why you think your process is the best.
7. We will hold discussion as usual on Wednesday afternoon.
Posted on 5/5/2008
Exam 3 and May 6 class
The solution to Exam 3 is now posted.
We will continue to work on the group project in class tomorrow. I will meet with each group to be sure you are on track. Please come prepared with your questions. Attendance and participation is a significant component of your project grade.
Finally, I will have to cancel office hours tomorrow PM because I need to go to a meeting with the Board of Regents.
Posted on 4/24/2008
Practice Exams and Project
I have posted 3 practice exams to help you prepare for Exam 3, which is coming up on May 1. I have also posted the project assignment (in the homework folder).
Posted on 3/7/2008
Office Hours
Office hours are Monday 2-4 PM (room 3105) and Tuesday 1-3 PM (room 3635). Drop by with your questions, comments, or concerns. Discussion is held Wednesday 1:20-3:15 in Room 2239. You may come and go as you please, work on your homework assignment, ask questions, and/or just socialize.
Posted on 2/9/2008
Tutoring Help at Wendt
There will be an undergraduate tutor, Courtney Barnes, available tomorrow night, and every Sunday night, for CBE 250, from 6:30-9 PM on the 4th floor of Wendt Library. She'd love to see you! There will also be another tutor, probably on Wednesday nights. Details forthcoming.
