HW2 - Department of Chemical Biochemical Engineering...

Department of Chemical & Biochemical Engineering
Rutgers, The State University of New Jersey
98 Brett Road
Piscataway, NJ 08854
54
14:155:201
Chemical Engineering Analysis I
Homework Assignment 2
(due 9/18/08)
1. Draw and label the streams described below and derive expressions for the indicated quantities in terms of labeled
variables. The following example is given as an illustration.
Example. A continuous stream contains 60.0 mole% benzene and the balance toluene. Write expressions for the
molar and mass flow rates of benzene
˙
n
B
(mol C
6
H
6
/s) and
˙
m
B
(kg C
6
H
6
/s), in terms of the total molar flow rate of
the stream,
˙
n (mol/s).
Solution:
˙
n
B
= ( 0.600 mol C
6
H
6
/mol)
˙
n (mol/s) = 0.600
˙
n (mol C
6
H
6
/s)
˙
m
B
= 0.600
˙
n (mol C
6
H
6
/s)( 78.1 g C
6
H
6
/mol) = 46.9
˙
n g C
6
H
6
/s
(a) The feed to a batch process contains equimolar quantities of nitrogen and methane. Write an expression for the
kilograms of nitrogen in terms of the total moles n (mol) of this mixture.