Transcript Microsoft Powerpoint 97 Slideshow Bioethanol of 1st and

Bioethanol Production
of 1st and 2nd Generation
3rd REBEL Partner Meeting, 27 May 2010
Sara Helmberger
Upper Austrian University of Applied Sciences Research and Development Ltd, Campus Wels
Content
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Introduction
World-leading bioethanol producing countries
Bioethanol production of 1st and 2nd generation
Various possible feedstocks
Production and processing technologies
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Introduction
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Fossil fuels are responsible for 73 % of the CO2 production in the atmosphere
Extreme contribution to global warming
Interest in development of methods, reducing green house gases
Bioethanol as alternative to petroleum-derived transportation fuels
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Definition Bioethanol
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Ethyl alcohol, grain alcohol, CH3-CH2-OH or EtOH
= Liquid biofuel
Advantages,
compared to gasoline:
- higher octane number
- broader flammability limits
- higher flame speeds
- higher heats of vaporization
- higher compression ratio
- shorter burn time
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Disadvantages,
compared to gasoline:
- lower energy density
- its corrosiveness
- low flame luminosity
- lower vapor pressure
- miscibility with water
Possible feedstocks: plant oils, sugar beets, cereals, organic waste,
processed biomass
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World-leading
bioethanol producing countries
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World-wide production of fuel ethanol more than tripled from 2000 until now
About 60% of global bioethanol production are obtained from sugar cane
and 40% from other crops (e.g. maize)
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North American
Ethanol production
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The United States are with over 41 % the world´s leader in ethanol production
Feedstocks: maize
wheat, barley, sorghum
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South American
Ethanol prodution
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South America contributes with roughly 35 % to world´s ethanol production, with
Brazil being the leader country
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Feedstock: sugar cane
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~ 20 % exported to US, EU, others
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European
Ethanol production
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Europe contributes with 9 % to world´s ethanol production
-> Comparable to the US ethanol market of roughly ten years ago
Plants in France, Spain, Sweden, UK, Austria (Pischelsdorf, Lower Austria)
In 2000, the EU introduced a Biofuel Directive
Commission of the European Communities (2007) -> binding minimal target
of 10 % biofuels by 2020
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Feedstock: wheat, sugar beet, waste from the wine industry
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European
Ethanol production
Bioethanol Plant in Pischelsdorf, Lower Austria
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Production technology
Feedstocks
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Bioethanol production
of 1st generation
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Major feedstocks for world´s ethanol production:
Sugar-containing feedstock: Sugar cane
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Starchy feedstock: Maize
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Bioethanol production
of 1st generation
Starchy materials (e.g. maize)
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US: 2 types of maize processing facilities:
- Wet milling (since 1980s)
- Dry grind (newer technology)
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Starch = a polysaccharide carbohydrate,
with a large number of sugar-molecules
Break down of the chains of this carbohydrate to obtain the single (individual) sugars
-> Hydrolysis technique
Fermentation with microorganisms (e.g. yeasts)
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Bioethanol production
of 1st generation
Sugar-containing feedstocks
(e.g. sugar cane, beet molasses, sweet sorghum)
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provide the single sugars (e.g. sucrose, glucose and fructose), which can be readily
fermented by microorganisms (yeast) -> no hydrolysis is necessary
Brazil: sugar cane
- harvest
- pressing
- Fermentation of sugar juice by microorganisms (yeast)
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Europe: Beet molasses
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Developing countries (e.g. Africa): Sweet sorghum
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Bioethanol production
of 2nd generation
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Feedstocks: Alternative or lignocellulosic materials
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= non food crops:
- waste and remnant biomass
- stalks of wheat and corn
- wood
- grass
- straw
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These most abundant reproducible feedstocks on Earth are of
- high yields
- low costs
- good suitability for low quality land
- low environmental impacts
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Bioethanol production
of 2nd generation
Lignocellulosic biomass
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3 basic polymers:
- Cellulose
- Hemicelluloses
- Lignin
Processing of lignocellulosic material to bioethanol
1. Pre-treatment
3. Fermentation
2. Hydrolysis
4. Product separation
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Bioethanol production
of 2nd generation
Pre-treatment
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Size-reduction
Removal of structural and compositional impediments
-> Lignocellulosic biomass is made more accessible for subsequent hydrolysis
Pre-treatment possiblities:
- mechanical
- chemical
- biological pre-treatment
- “Steam Explosion”
Steam Explosion:
- Biomass is extruded at high temperature and pressure
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Bioethanol production
of 2nd generation
Pre-treatment: Steam Explosion
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Bioethanol production
of 2nd generation
Hydrolysis
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= Saccharification of lignocellulosic biomass
Cellulose and Hemicellulose have to be broken down into single (individual) sugar
molecules
Catalyst:
- dilute acid
- concentrated acid
- enzymes (so-called cellulases)
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Enzymatic hydrolysis
- Cellulases are produced from both fungi and bacteria
- Hydrolysis at mild conditions (50°C and pH 5.0)
- Effective cellulose and hemicellulose breakdown
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Bioethanol production
of 2nd generation
Fermentation
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The hydrolysate (mixed sugar-solution) is then fermented by microorganisms
(e.g. yeast)
The sugar-solution contains not only one kind of sugar, but several different kinds
-> Microorganisms are required, that can convert all sugars to high yields of EtOH
Most effective producer of bioethanol: Saccharomyces cerevisiae
- can ferment only one kind of sugar
- metabolic engineered strain or
adapted strain of yeast is required
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Bioethanol production
of 2nd generation
Product separation, Distillation
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Distillation
- Bioethanol is separated from water
- Ethanol is concentrated to about 95.6 %
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Value-added co-products (e.g. lactic acid)
- processing into plastics or other products
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Lignin
- usage in various value-added applications
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Bioethanol
usage
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Thank you for your attention !
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