# Chapter 3 Example

## Oxidation of Naphthalene to Phtahalic Anhydride

Taking A as the basis of calculation, A + 9/2 B → C + 2D + 2E

We are going to rework the class problem for the case of 3.5% naphthalene and 96.7% air and for a pressure of 10 atm and a temperature of 500K. A feed under these conditions naphthalene is the limiting reactant.

1. Stoichiomentric Table - Batch System

 Species Symbol In Change Out Naphthalene A NA0 -NA0X NA = NA0(1-X) Oxygen B NB0 = NA0 -9/2NA0X NB = NA0( - 9/2X) Phthalic Anhydride C NC = 0 +NA0X NC = NA0X Carbon Dioxide D ND = 0 +2NA0X ND = 2NA0X Water E NE = 0 +2NA0X NE = 2NA0X Nitrogen I NI = NA0 --- NI = NA0 Total NT0 NT = NT0 + NA0X = [1 + 2 + 2 - 9/2 - 1] = -1/2
Stoichiometric Table - Flow System
 Species Symbol In Change Out Naphthalene A FA0 -FA0X FA = FA0(1-X) Oxygen B FB0 = FA0 -9/2FA0X FB = FA0( - 9/2X) Phthalic Anhydride C FC = 0 +FA0X FC = FA0X Carbon Dioxide D FD = 0 +2FA0X FD = 2FA0X Water E FE = 0 +2FA0X FE = 2FA0X Nitrogen I FI = FA0 --- FI = FA0 Total FT0 FT = FT0 + FA0X

2. Determine each of the following soley as a function of the conversion of naphthalene, X for a constant-pressureisothermal flow reactor.
1. Find the concentration of O2
Gas Phase Flow System:

Constant pressure and isothermal: P = Po; T = To

2. Find the volumentric flowrate

Constant pressure and isothermal: P = Po; T = To

3. Find the reaction rate
Rate Law:     -rA = kAC2ACB

For a constant volume isothermal batch reactor,
1. The concentration of O2
For Batch: V = V0, CB = NB/V = NB/V0

2. The total pressure, P.

3. The rate law
Rate Law:     -rA = kAC2ACB

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