Synthetically produced ethanol is an important industrial commodity used for various purposes, including as a solvent (especially for substances intended for human contact or consumption); in coatings, inks, and personal care products; for sterilization; and as a fuel. Industrial ethanol is a petrochemical synthesized by the hydrolysis of ethylene: C2H4 (g) + H2O (v) <=>C2H5OH (v)
Some of the product is converted to diethyl ether in the undesired side reaction:
2 C2H5OH (v)<=> (C2H5 )2O (v) + H2O (v)
The combined feed to the reactor contains 53.7 mole% C2H4, 36.7% H2O, and the balance nitrogen, and enters the reactor at 310oC. The reactor operates isothermally at 310oC. An ethylene conversion of 5% is achieved, and the yield of ethanol (moles ethanol produced/moles ethylene consumed) is 0.900. Hint: treat the reactor as an open system.
Data for Diethyl Ether:
ˆ
H of = -271.2 kJ/mol for the liquid
ˆ
Hv = 26.05 kJ/mol (assume independent of T )
Cp[kJ/(molC)] = 0.08945 + 40.33*10-5T(C) -2.244*10-7T2
(a) Calculate the reactor heating or cooling requirement in kJ/mol feed.
(b) Why would the reactor be designed to yield such a low conversion of ethylene? What processing
step (or steps) would probably follow the reactor in a commercial implementation of this process?