Ethylene oxide is produced through the direct oxidation of ethylene using a silver oxide catalyst between 250-300°C and 4-5 atmospheres of pressure. Ethylene and air are mixed and passed over the catalyst, and the highly exothermic reaction produces ethylene oxide with a 60-70% yield. The effluent gases are washed and the absorbed ethylene oxide is separated through fractional distillation, producing a 95-98% pure product. Major engineering challenges include controlling the air-to-ethylene ratio and preventing the competitive oxidation reaction to carbon dioxide and water.

1. ETHYLENE
OXIDE BY
DIRECT
OXIDATION OF
ETHYLENE
By
Sameer Raza (102112038)
G.Venkatesh (102112025)

2. CONSUMPTION PATTERNS
Used as a permanent antifreeze for
automobile radiators.
Production of:
Ethylene glycol polyesters
Non-Ionic detergents
Ethanol amines

3. Methods of Production
Direct oxidation of
ethylene
Chlorohydrination of
ethylene

4. Chemical Reaction

5. Catalyst and operation
conditions
Catalyst: Silver Oxide
Operating Conditions:
250-300
o
C
Pressure: 4-5 atms

6. Quantitative Requirements
 Basis: 1 ton of ethylene oxide (99% purity, 70%
yield)
 Ethylene 0.92 ton
 Air 9.0 tons
 Silver 0.3 kg in fixed bed
0.7 kg in fluidised bed
 Ethylene dichloride suppressor 10-15 kg
 Electricity 1500 kWh
 Steam 0.1ton
 Water 180 tons

7. Flow Sheet

8. Process Description
 Ethylene oxide of 95-98% purity and air are
compressed separately, mixed together
giving 3-10% C2H4 volume concentration
and passed over a catalyst of silver oxide
on a porous inert carrier such as alumina.
A side reaction suppressing agent such as
ethylene dichloride is added to the feed
to reduce the competitive oxidation
reaction to CO2 + H2O.

9.  The reaction is highly exothermic and is
best carried out in a fixed bed tubular
reactor in which heat transfer salt or
Dowtherm is pumped around the tube
within the shell to maintain a 250-300oC
temperature. Heat is recovered in a
waste-heat steam boiler. A short
residence time of 1 sec in plug flow is the
design with an ultimate yield of 60-70%.

10. ° The effluent gasses from the reactor are
water washed under pressure. The absorbed
ethylene oxide is sent to a packed bed
desorber-fractionator tower and taken
overhead. It still contains a large amount of
water vapour plus some impurities. This
stream is compressed to 4-5 atm and
fractionated twice to remove the light ends,
water and high boiling polymers.

11. Major Engineering Problems
 Volume ratio of air
–ethylene.
 Air versus oxygen.
 Hydration of
ethylene oxide to
glycol.
 Fluidized bed
versus fixed bed.
 Use of reactors in
series.

12. References
 Dryden’s outlines of
chemical
technology.
 http://nptel.ac.in/c
ourses/103103029/1
7
 http://www.essenti
alchemicalindustry.
org/chemicals/epo
xyethane.html