524
stability of the catalyst [162]. A list of catalysts that display nearly 100% ethanol
conversion with ~99% selectivity for ethylene is presented in Table 3.
Commercial plants, which are in operation for the production of ethylene from
bioethanol are America Halcon Scientific Design Inc., USA (with Synthol catalyst,
Al 2 O 3 -MgO/SiO 2 ); British Petroleum (Hummingbird process, heteropoly acid catalyst); Axens (Atol process); Chematur; Braskem, Brazil; and Dow Chemical [162,
164–166]. Though the processes could be operated with very high efficiency, cost
of ethylene from bioethanol is higher in comparison with ethylene from steam
cracking (SC) process due to higher cost of bioethanol and very high energy efficiency realized in mega-scale ethylene plants based on SC.
4.3 Conversion of Bioethanol-Derived Ethylene to C 3 ,
C 4 Olefins
As illustrated by Hulea [165], well-established olefins conversion processes like
dimerization, metathesis, oligomerization, isomerization, cracking and aromatization could be applied for the conversion of bio-based ethylene to value-added products (Fig. 15).
Both homogeneous and heterogeneous catalysts have been studied extensively
[167, 168] for the dimerization of ethylene to 1-butene, an important co-monomer
in the manufacture of commodity polyolefins, like linear low-density polyethylene
(LLDPE). Commercial process for the manufacture of 1-butene, the AlphaButol
technology developed by Axens and SABIC, is based on highly selective (93%)
Table 3 Selected catalysts for dehydration of ethanol to ethylene (Adopted from Fan et al. [162])
Catalysts
Ethylene
selectivity, %
Ethanol
conversion, %
Reaction
temp., °C
LHSV
a
/
WHSV
b
/
GHSV
c , h
−1
Lifespan,
stability
TiO 2 /γ-Al 2 O 3
99.4
100
360–500
26–234
a
400 h, stable
0.5% La-2%
P-HZSM-5
99.9
100
240–280
2
b
Very stable
Nano-CAT
99.7
100
240
1
b
630 h, very
stable
Ag 3 PW 12 O 40
99.2
100
220
6000
c
Stable in 9%
humidity
TPA-MCM-41
99.9
98
300
2.9
b
Very stable
STA-MCM-41
99.9
99
250
2.9
b
Stable
TRC-92
99.0
70
280
2.9
b
Very stable
SynDol (Halcon)
(SD, USA)
96.8
99
450
26–234
a
Very stable
a
Liquid hourly space velocity (LHSV)
b
Weight hourly space velocity (WHSV)
c
Gas hourly space velocity (GHSV)
R. Vinayagamoorthi et al.
stability of the catalyst [162]. A list of catalysts that display nearly 100% ethanol
conversion with ~99% selectivity for ethylene is presented in Table 3.
Commercial plants, which are in operation for the production of ethylene from
bioethanol are America Halcon Scientific Design Inc., USA (with Synthol catalyst,
Al 2 O 3 -MgO/SiO 2 ); British Petroleum (Hummingbird process, heteropoly acid catalyst); Axens (Atol process); Chematur; Braskem, Brazil; and Dow Chemical [162,
164–166]. Though the processes could be operated with very high efficiency, cost
of ethylene from bioethanol is higher in comparison with ethylene from steam
cracking (SC) process due to higher cost of bioethanol and very high energy efficiency realized in mega-scale ethylene plants based on SC.
4.3 Conversion of Bioethanol-Derived Ethylene to C 3 ,
C 4 Olefins
As illustrated by Hulea [165], well-established olefins conversion processes like
dimerization, metathesis, oligomerization, isomerization, cracking and aromatization could be applied for the conversion of bio-based ethylene to value-added products (Fig. 15).
Both homogeneous and heterogeneous catalysts have been studied extensively
[167, 168] for the dimerization of ethylene to 1-butene, an important co-monomer
in the manufacture of commodity polyolefins, like linear low-density polyethylene
(LLDPE). Commercial process for the manufacture of 1-butene, the AlphaButol
technology developed by Axens and SABIC, is based on highly selective (93%)
Table 3 Selected catalysts for dehydration of ethanol to ethylene (Adopted from Fan et al. [162])
Catalysts
Ethylene
selectivity, %
Ethanol
conversion, %
Reaction
temp., °C
LHSV
a
/
WHSV
b
/
GHSV
c , h
−1
Lifespan,
stability
TiO 2 /γ-Al 2 O 3
99.4
100
360–500
26–234
a
400 h, stable
0.5% La-2%
P-HZSM-5
99.9
100
240–280
2
b
Very stable
Nano-CAT
99.7
100
240
1
b
630 h, very
stable
Ag 3 PW 12 O 40
99.2
100
220
6000
c
Stable in 9%
humidity
TPA-MCM-41
99.9
98
300
2.9
b
Very stable
STA-MCM-41
99.9
99
250
2.9
b
Stable
TRC-92
99.0
70
280
2.9
b
Very stable
SynDol (Halcon)
(SD, USA)
96.8
99
450
26–234
a
Very stable
a
Liquid hourly space velocity (LHSV)
b
Weight hourly space velocity (WHSV)
c
Gas hourly space velocity (GHSV)
R. Vinayagamoorthi et al.