Documentation:CHBE Exam Wiki/Midterm Exam 2 2016W/MT2 Question 3

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Final Exam 2016W
Midterm Exam 1 2016W
Midterm Exam 2 2016W
Problem Sets
Module 1 - Process Basics
Module 2 - Reactors
Module 3 - Separations 1
Module 4 - Separations 2
Module 5 - Non-reactive Energy Balances
Module 6 - Reactive Energy Balances


Catalytic converters are used in cars to oxidize emission compounds in order to make them less toxic. A similar process may be used in a chemical plant to clean up emissions. A waste gas contains 0.5 mol% C3H8 (propane), 8.5 mol% CO2, 4 mol% O2, 10 mol% H2O and the remainder inert nitrogen (N2). In order to try to remove the propane, it undergoes complete combustion with a catalyst and can be modeled as a reversible reaction. This reaction is undertaken at 1 atm.

Question 3a [5 points]

Is there excess oxygen, if so, what is the % excess of oxygen?




Question 3b [15 points]

Write out a formula for the equilibrium constant (Ke) in terms of the pressure (P), reaction extent (E) and molar feed (n°C3H8, n°CO2, n°O2, n°H2O, n°N2) of each compound. Simplify the expression algebraically as much as possible. Note that you should not need to perform any calculations for this.




Question 3c [15 points]

A conversion of 95% of propane from the combustion reaction is achieved. Following this, the remaining propane is removed using an adsorption bed at the same pressure containing 1 tonne activated carbon. Laboratory experiments were undertaken to model the adsorption of propane and gave the results found below, given this how many kilograms of propane can this bed remove?



where




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