RB: Reactive Recycle Example

Reactive Recycle Example

Ethylene oxide is produced by burning ehtylene

2C2H4 + O2 -> 2C2H4O

an undesired side reaction is the complete combustion of ethylene

C2H4 + 3O2 -> 2CO2 + 2H2O

The feed to the reactor (not the process!) contains 3 moles of ethylene per mole of oxygen. The single-pass conversion of ethylene is 20% and for every 100 moles of ethylene consumed in the reactor 90 moles of ethylene oxide are produced. A complex separation system is used so that ethylene and oxygen may be recycled to the reactor, while carbon dioxide and water are discarded and ethylene oxide is packaged and sold.

Assume a 100 mol/hr feed rate of ethylene to the reactor.


How many Unknowns are there?
How many different (reactive) Atomic Species are there?
How many Process Specifications are we given?
How many Physical Constraints are there?
The total number of Degrees of Freedom is