Cb. Phillips et R. Datta, PRODUCTION OF ETHYLENE FROM HYDROUS ETHANOL ON H-ZSM-5 UNDER MILD CONDITIONS, Industrial & engineering chemistry research, 36(11), 1997, pp. 4466-4475
Due to the dramatic rise in the use of ethers as fuel oxygenates, an a
lternative process far the production of ethyl tert-butyl ether (ETBE)
based solely on biomass-derived ethanol feedstock is proposed. The fi
rst step in this process is ethanol dehydration an H-ZSM-5 to produce
ethylene. Hydrous ethanol is a particularly attractive feedstock for t
his step since the production of anhydrous ethanol is very energy/cost
intensive. in fact, the presence of water in the ethanol feed enhance
s the steady-state activity. and selectivity of M-ZSM-5 catalysts, Rea
ction kinetic data were collected in a microreactor at temperatures be
tween 413 and 493 K, at ethanol partial pressures of less than 0.7 atm
, and at water feed molar ratios of less than 0.25, A sharp initial de
cline in catalyst activity observed within a few minutes on stream was
attributed to the formation of ''low-temperature coke'' from ethylene
oligomerization. Deactivation occurred at a much slower rate after 10
0 min on stream, allowing near-steady-state data to be collected, Wate
r in the ethanol feed enhanced the steady-state catalytic activity and
ethylene selectivity by moderating the acidity of the catalytic sites
, resulting in less extensive deactivation due to caking.