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Assignment 11. The reaction AB is carried in a plug flow reactor
(PFR). The
concentration of reactant A along the reactor is given by the
following expression:
Find an algebraic expression of the concentration of reactant A
at steady state for any given differential volume in the PFR
using:
Forward finite differences
Backward finite differences
Central finite differences
rz
CDz
uCt
CA
AAA +
+
=
2
2)(
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Assignment 1
2. Calculate the bubble point temperature and
equilibrium composition associated with a liquid
mixture of 10 mol% n-pentane and 90mol% n-
hexane at 1 atm.
Vapor pressure of n-pentane PA* (in mm Hg)
and n-hexane PA* (in mm Hg) can be
calculated from Antoine Equation (T is in C):
23263.106485221.6log *
+=
TPA
TPB +
=
366.22453.117187776.6log *
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3. The zeta-potential of particles in a suspension
is an indication of the sign and the density of the
surface charge of the particles. The iso-electric
point refers to the pH where the zeta-potential
is zero. Use the data given in the Table to
determine the iso-electric points of silica in the
presence of 10-4 M Pb(NO3)2. Use quadratic
polynomial for interpolation using Lagrange
method.
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pH Zeta-potential (mV) pH Zeta-potential (mV)
1.74 -5.3 6 -33.2
2.72 -10.8 6.53 -15.7
3.72 -21.8 6.7 -10
4.09 -32 7.29 13.7
4.32 -35.8 8.06 32.2
4.70 -36.9 10.02 24
5 -36.7 11.12 6.9
5.55 -37.7 12.15 -30
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4.Paraxylene, Styrene and benzene are to be
separated with the array of distillation columns
shown in the figure (operating at steady state):
Calculate the molar flow rates
D1,D2,B1 and B2.
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The fanning friction factor can be used to
calculate the friction loss for isothermal liquid
flow in uniform circular pipes by the formula:
DLvfF Ff
2
2=
5. A heat exchanger is required that will be
able to handle 2.5 liter/s of water through a
smooth pipe with an equivalent lenght of
L=100 m. The maximum total pressure drop is
to be P=103kPa at a temperature of 25C. Calculate the diameter D
of the pipe required
for this application, having into account the
following:
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The friction factor can be used to predict the
pressure drop due to frictions loss from:
Where pf is the pressure drop in Pa and isthe density in
kg/m3
If the flow is in the laminar region the fanning
factor can be calculated as:
Ff Fp =
Re/16=Ff
Where Ff is the friction loss in J/kg, fF is the
fanning friction factor (dimensionless), L is the
length of the pipe in m, v is the fluid velocity in
m/s and D is the pipe diameter in m.
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For turbulent flow in a somooth tube, the
Nikuradse correlation can be used for
calculating the fanning factor:
Use two different method sfor solving the
problem.
( ) 4.0Relog41 = FF
ff
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The friction factor f for turbulent flow of an
incompressible fluid in a pipe is given by the
nonlinear Colebrook Equation:
Assignment 1
+
= f
Df Re
51.27.3
/ln86.01
Where and D are the roughness and insidediameter of the pipe and
Re is the reynolds number.
Calculate the friction factor for flow of a fluid in a
pipe with /D=10-4 y Re=105.
Use the successive substitutution, newton and a
third method and compare them.
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Assignment 16. The heat capacity of gaseous propane is presented
in the following table:
Determine the mean heat capacity for the following
intervals:
50 K to 1500 K
50 K to 273.15 K
273.15 K to 1000 K
1000 K to 1500 K
Temperature (K) Heat Capacity
(kJ/kg-mol.K)
Temperature (K) Heat Capacity
(kJ/kg-mol.K)
50 34.06 700 142.67
100 41.30 800 154.77
150 48.79 900 163.35
200 56.07 1000 174.60
273.15 68.74 1100 182.67
300 73.93 1200 189.74
400 94.01 1300 195.85
500 112.59 1400 201.21
600 128.70 1500 205.89
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Assignment 17. A polymer-surfactant system is used to produce
nanoparticles
encapsulating active ingredients for controlled release. The
effect of surfactant concentration on the encapsulation
process are presented in the following table:
Use these results to determine the optimum concentration of
surfactant that maximizes the effective drug loading (Drug
loading x Encapsulation efficiency)
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Assignment 1
Investigate about the Runge phenomenon
