. 2C2H4 + O2 2C2H4O

An undesired competing reaction is the combustion of ethylene:

C2H4 + 3O2 2CO2 + 2H2O

The feed to the reactor (not the fresh feed to 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 emerge in the reactor products. A multiple-unit process is used to separate the products: ethylene and oxygen are recycled to the reactor, ethylene oxide is sold as a product, and carbon dioxide and water are discarded.

(a) Assume a quantity of the reactor feed stream as a basis of calculation, draw and label the owchart,

perform a degree-of-freedom analysis, and write the equations you would use to calculate (i) the molar ow rates of ethylene and oxygen in the fresh feed, (ii) the production rate of ethylene oxide, and (iii) the overall conversion of ethylene. Do no calculations.

(b) Calculate the quantities specied in Part (a), either manually or with an equation-solving program.

(c) Calculate the molar ow rates of ethylene and oxygen in the fresh feed needed to produce 1 ton per hour of ethylene oxide. the fresh feed to the reactor.

(a) Assume a methanol production rate of 100 kmol/h. Perform the DOF for the overall system and all

subsystems to prove that there is insufcient information to solve for all unknowns.

(b) Briey explain in your own words the reasons for including (i) the recycle stream and (ii) the purge stream in the process design.