Chemical and Biomolecular Engineering 301
Final Exam 12/02/05
Return to AL B216 by 5PM on 12/14/05

Open text, notes and computer.
Four hour total time limit, but you may take a break in the middle.
During the break, you are encouraged to contact the instructor
if you have any questions about the problems, but you may not
study material in the course.  Sending e-mail to shdavis@rice.edu 
and/or kyzy@rice.edu
should be the most efficient way to contact us.














In each part of each of the following problems, you should:
a) Carefully specify the system for which you intend to write balances,
b) Specify whether the system is steady state or dynamic,
c) Specify whether the system is open or closed,
d) Specify the basis (if necessary) you will use in the solution.
e) For problems solved with the Matlab modules, use the function showe to display the flows and other properties of all streams in each unit analyzed.
f) Show how a degree of freedom analysis can be used to determine whether problems 1 to 3 have the same number of unknowns as specifications and how mass and energy balances play a roll in determining your final answers.


1) 25 Points
Properties of several types of coal are given in Table 4.15 of Reklaitis.  Properties of three are shown in the following table:

Coal Source
Type
Moisture
Ash
C
H
N
S
O
Montana
Sub-bituminous
19.84
9.16
68.39
4.64
0.99
0.79
16.03
Illinois
Bituminous
12.10
10.84
68.92
5.01
1.01
6.66
7.57
Penna.
Anthracite
1.25
8.32
83.67
3.56
0.55
1.05
2.85

All compositions shown in this table are given as mass per cent on a dry basis.  In addition the moisture is lbm of moisture per 100 lbm of dry coal.

The higher heating value of each coal may be estimated using the formula given in Reklaitis:

HHV = 14658C +56878H +2940S -658ash -5153(O + N)
Where the HHV is in Btu/lbm,
 And all compositions are in weight fractions on a dry basis.


a)  For each ton (2000 lbm) of each coal (including the moisture in it) burned, determine the pounds of SO2 produced.
b) Estimate the amount of heat released by burning one ton of each wet coal with air to produce CO2,(g) H2O(l), SO2(g), O2(g) and N2(g) and ash, if all reaction products exit at 25¡C.   Gvie your answer in Btu per ton.

2) 25 points
Work problem 7.43 in your text.

3) 25 points
Work problem 8.52 in the text.   Use data in the chbe301 data bank for both compounds in this problem.  Does your answer to part (a) agree with the text's answer?

4) 25 points
Work problem 11.27 in the text.  You should also find the time required for the concentration in the fluid in the tank  to reach 99% of the value in the inlet stream.   In this problem, you must work all parts by hand without using Maple or any other computer program.


Pledge