CONTEMPRORARY ISSUES
1.
Identify systems with chemical conversions in your environment. Classify the reactor
types as one of the ideal reactors. Comment on the deviations from the ideal
behavior in the systems you chose.
2.
Identify the most recent reactor technology in your nearest chemical plant. Why did
they choose that?
3.
Familiarize yourself with internal combustion engines. Describe the features of a
Diesel engine cylinder as a chemical reactor. Is it isothermal, adiabatic, constant
volume, constant pressure?
4.
What is the contribution of the internal combustion engines on the CO 2 emissions
and global warming?
5.
What is the contribution of the internal combustion engines to NOx emissions?
6.
Browse through the literature on chaos theory. Do you find any analogies between
multiple steady states and chaotic behavior?
END OF CHAPTER PROBLEMS
1.
Using the batch reactor design equation and the general energy balance, address the
following:
a.
For a constant pressure first order gas phase adiabatic reaction, derive the
mathematical expression between temperature and conversion.
b.
Derive the equivalent expression if the volume is constant.
c.
Compare the equations you derived in parts a and b and comment on whether
you achieve higher conversions in constant volume or constant pressure
reactors.
2.
The automobile engine can be considered as a batch reactor. In Diesel engines,
combustion takes place at constant pressure, while in Otto (gasoline) engines it takes
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place at constant volume. Based on your answers to problem 1, comment on which
type of reactor is favorable, given that the objective in these reactors is to convert
heat to work.
3.
A bimolecular liquid phase reaction with the stoichiometry A+B→R+S is taking place
in a batch reactor. Derive the expressions to determine the time progress of
concentration for each of the following cases:
a.
[A]0=[B]0
b.
[A]0=2[B]0
c.
[A]0=[B]0=1/2 [R]0
d.
If the concentration versus time data were available, how would you determine
the rate constant k? Explain.
4.
The corresponding equations if the bimolecular reaction of question 3 were taking
place in the gas phase in a
a.
Constant volume batch reactor.
b.
Constant pressure batch reactor.
c.
Rework problems 3 and 4 for a CSTR and PFR operating at steady state.
d.
How would you determine the optimum temperature profile for minimum
reaction time and minimum energy use in a batch reactor?
5.
Draw the heat generation and removal curves for the CO oxidation reaction. The
reaction is taking place over 1wt% Pt/Al2O3 catalyst. CO is fed to the reactor mixed
with stoichiometric amount of oxygen. The feed gases enter the reactor at 300 K and
at a flow rate of 200 cc/min. 100 mg of catalyst is used. Solve this problem for the
following situations:
a.
The feed contains only the pure reactants.
b.
50 % of the feed gases are the reactant gases at reaction stoichiometry and the
rest is N2.
c.
50 % of the feed gases are the reactant gases at reaction stoichiometry and the
rest is He.
Now redo parts a-c if the heat capacity of the catalyst and the reactor are nonnegligible. The reactor is made of quartz and weighs about 10 g.
You may assume that the activation energy of the reaction is 150 kJ/mol.
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6.
Discuss the role of the diluent in establishing the stability of an adiabatic reactor. Pay
special attention to differentiate between the diluent gas and the catalyst diluent in
solid state.
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