Exam II - Winter 1995

(30 pts)

1) The irreversible gas phase solid catalyzed reaction

A + B -> C + D

is carried out isothermally in a differential packed bed reactor. The following data were recorded.
Run-r'APAPBPCPD
mol/kg cat-minatmatmatmatm
151100
251.250.52020
350.876250
451.25.500
550.85750
6255100
72545100
8253.8810010
9253.775000
105010142

(a)Determine a rate law consistent with the experimental data.
(b)Suggest a mechanism and rate limiting step consistent with your rate law.
(c)Linearize your data and evaluate the rate law parameters (Note: you don't have to plot all the data, just a few representative points)

(30 pts)

2) The elementary reversible gas phase reaction A <->2B is to be carried out adiabatically. Pure A is fed at a rate of 2 mol/min, a temperature of 100šC, and a concentration of 0.01 mol/dm3.

(a)What is the adiabatic equilibrium temperature and conversion.
(b)What is the CSTR volume necessary to achieve 80% of the adiabatic equilibrium conversion?
Graphs of k(T) and KC are shown below.TkKC Xe
CpA = 5.0 cal/(mol - šC)šCmin-1mol/dm3 --
CpB = 2.5 cal/(mol - šC)1000.0860.050.75
CpC = 5.0 cal/(mol - šC)2000.270.018
HR(100šC)=-3500 cal/mol A3000.620.0096
4001.050.0060.36

(25 pts)

3) The elementary reaction

2A -> 2B

is carried out in a moving bed reactor in which the catalyst decays by sintering. What catalyst weight is necessary to achieve 50% conversion for a catalyst loading rate of 5 kg/min? Pure A is fed to the reactor at a concentration of 0.2 mol/dm3 and a molar flow rate of 5.0 mol/min.

Specific Reaction Ratek=1.0 dm6 /(mol-kg cat-min)
Catalyst decay constantkd=0.04 min-1

(15 pts)

3) The elementary reaction

A -> B

is irreversible and carried out adiabatically in a CSTR. The R(T) and G(T) (kcal/mol) are shown in the attached figure.

(a)What is the heat of reaction for this reaction?
(b)What is the heat capacity of species A?
(c)What is the entering temperature at which ignition will occur?

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