The Green Path to Ethylene Conclusion

Shravanthi Galiveti
Department of Chemistry
The Green Path to Ethylene
3 Production
Sucrose, starchy and ligno-cellulosic biomass, can be used to produce bioethanol. Sucrose biomass such as sugarcane, sugar beets and sweet sorghum, can be converted
to ethanol via fermentation by yeast. Starchy biomass, such as corn and wheat must first be hydrolyzed before fermentation. Ligno-cellulosic biomass, e.g. wood, straw
and grass, follow a more complicated process of hydrolysis and fermentation.3
1
Introduction
Ethylene is one of the most
important feedstocks for the
chemical industry – 75% of
petrochemical products are derived
from ethylene, as well as the largest
produced by volume – 142 million tons of
ethylene was produced in 2011, and this
figure is growing.1,2 However it’s derived
from finite fossil fuels and produces the
most greenhouse gas (GHG) emissions, so
a greener alternative is needed.2
Currently around 99% of ethylene is produced through hydrocarbon
cracking. Ethylene used to be made from ethanol until 1940, when the
steam cracking of petrochemical feed stocks offered a cheaper
alternative.
Bio-ethylene can be produced through catalytic, gas - solid
phase, dehydration of ethanol.4 The process can achieve a
high selectivity with yields between 94-99% and uses
activated phosphoric acid, oxides, molecular sieves, or
other miscellaneous acids as catalysts. Alumina based
catalysts are most common in today’s industrial reactors.1
The global market for biopolymer production is
expanding, with ethylene used in the production of
around half of all plastics, many new bio-ethylene plants
have been commissioned.3
The recent boom in shale gas production will lower the
price and availability of ethane; this is likely to have
negative effects on the bio-ethylene industry.5
Dehydration
6 Conclusion
Catalyst
4
What is it?
Benefits
Bio-ethylene is a chemically identical
version of ethylene that is derived from
bioethanol, which in turn comes from
biomass sources. Bioethanol is a widely
used fuel in the transport industry, with
about 100 billion liters produced yearly.3
 No new technology needed for conversion of
bio-ethylene to derivates.
 Average life cycle GHG emissions can be up to
40% lower and 60% more fossil fuel energy is
saved.
 Sucrose derived ethanol process byproducts
generate electricity that can be exported.
 Renewable energy source – less dependence
on finite fossil fuels.
 Economic benefit - lowers import of fossil
fuels and stimulates local employment.
 Large biomass reserves, with global
production expected to produce between 1.5
– 4.5 x1011 GJ by 2050.
 Bio-polymers can be sold for a premium price
of approximately 15-30%.3
Ethylene Derivatives
Others
8%
Ethylene
Benzene
7%
EDC
13%
Ethylene
Oxide
13%
References
1.
2.
Y. Yu, and M. Zhang, Ind. Eng. Chem. Res, 2013, 52, 9505-14
C. Eckert, W. Xu, W. Xiong, S. Lynch, J. Ungerer, L. Tao, R. Gill, P. Maness, J. Yu, Biotechnol Biofuels, 2014, doi:
10.1186/1754-6834-7-33.
Industry
The USA is the world’s
largest producer of bio-ethylene,
contributing 63% of global production
and Brazil is second, with 24%. The largest
bio-ethylene plants are capable of producing
around 200kt of bio-ethylene per year.
Pre-treated ethanol is fed into the reactor.
• Temperatures are in the region of 300− 500 °C
• Pressure of 0.1− 0.2 MPa
• Main byproduct - diethyl ether - generated at <573K
The crude ethylene is then purified in a series of towers.1
2
Polyethene
59%
5
Barriers
⤫ Future biomass availability is uncertain.
Depends upon food requirements, and
industry demand from the chemical,
energy and transportation sectors.
⤫ Biomass from food feedstocks such as corn
and sugarcane, reduces food supply, thus
adversely affecting prices. Especially
damaging in developing countries.
⤫ EU import duty on ethanol - upto $310
per ton, unfavourable to import for use as
a feedstock.
⤫ Bio-ethylene production is more expensive
than the global average petrochemical
production costs by 10-130%.
⤫ Conversion of pristine land to biomass
products can release a significant amount
of GHG emissions.3
3.
4.
5.
Mean Ethylene
Production Cost3
2570
2060
1650
Climate change is a serious threat to our world. Bio-ethylene
is a step in the right direction to lowering the environmental
impact of the ethylene and wider chemical industries.
Furthermore, the gap between finite fossil
fuels and bio-based fuels is likely to narrow in the
long run as oil reserves are depleted and
technology advances. Ligno-cellulosic biomass
shows the greatest potential, as it requires
less land, 100% of the material can be
converted, and has little effect on food
supply.3 In the future bio-ethylene
will be an increasingly important
part of the chemical industry.
.
1190 1220 1100
EU-sugar beets
China-sweet sorghum
India-sugarcane
USA-corn
Brazil-sugarcane
Global-petrochemical
IEA-ETSAP and IRENA, Production of Bio-Ethylene: Technology Brief, IRENA Report, 2013
G. Chen, M. K. Patel, Chem Rev, 2012, 112, 2082-99
Market outlook: Shale gas impacts bio-based chemicals, http://www.icis.com/Articles/2013/06/07/9676331/marketoutlook-shale-gas-impacts-bio-based-chemicals.html, (accessed April 2013).
`