RICH – MAC TECHNOLOGY ROUNDTABLE
AIDIC BWG ITALIAN ASSOCIATION OF CHEMICAL ENGINEERING
BIOTECH WORKING GROUP
Aurelio VIGLIA AIDIC BWG
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RICH – MAC TECHNOLOGY ROUNDTABLE
PRESENTING
BIOENERGY VECTORS
To The Rich – Mac Technology Round Table
Milan, Italy October 5, 2005 Presented by Aurelio Viglia
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SUMMARY
The increasing cost of fossil fuels and the associated
environment degradation are addressing the Public Opinion and Governments to have a better
consideration of all integrative energy sources, mainly
the renewable ones.
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SUMMARY (2)
In this frame, the main focus of the following presentation is on the biologically producible energy: - Hydrogen by microorganisms utilisation
- Biodiesel from algae cultivation
- Ethanol from biomass, both from agriculture and organic waste - Biomethane from organic waste
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HYDROGEN
• 1990, Japan launches an huge R&D program for hydrogen production based on microalgal biomass fermentation; • 1995, USA and Japan enlarge R&D’s field on H2 production through photosynthetic and chemoautotrophic bacteria; • In the most recent years, the researchers have discovered the possibility to produce hydrogen by anaerobes and methylotrophic too.
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MICROBIAL HYDROGEN PRODUCTIVITY
Photosynthetic Rodospirillum rubrum produces 4, 7 and 6 mol of H2 from acetate, succinate, and malate, respectively • Anaerobic Clostridia are H2 producers and immobilised C. butyricum produces 2 mol H2/mol glucose at 50% efficiency. H2 FIRST CONCLUSION • After more than 20 years research, it is possible to affirm that the fate of H2 biotechnology is presumed to be dictated by the stock of fossil fuels and state of pollution in future.
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H2 by Microbial Fuel Cell: 2005 Situation
• Using a new electrically-assisted microbial fuel cell (MFC) that does not require oxygen, an USA company developed the first process that enables bacteria to coax four times H2 directly out of biomass than can generated typically by fermentation alone; • In the new MFC, when the bacteria eat biomass, they transfer electrons to an anode. Bacteria also release protons, hydrogen atoms stripped of their electrons, which go into solution. The electrons on the anode migrate via a wire to the cathode, the other electrode in the FC, where they are electrochemically assisted (BEAMR) to combine with the protons and produce H2.
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H2 SECOND CONCLUSION
• New MFC demonstrate, for the first time, that there is a real potential to capture hydrogen for fuel from renewable sources for clean transportation.
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BIODIESEL AND ALGAE CULTIVATION (1)
• 1960’s, Research starts on Microalgae Cultivation to convert sunlight energy into biomass as feeding for biomethane production; bio-methane is the fuel for SMS Electrical Power Stations; • Early 1980’s, DOE grants the <
> with the aim to produce algal oils for biodiesel production; • 2005, Australia focus its attention on Botrycoccus braunii (Bb), a green alga able to produce high quantities of various kinds of hydrocarbons.
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BIODIESEL AND ALGAE CULTIVATION (2)
• Bb synthesize hydrocarbons up to 75% of its dry weight; • For this reason Australian Government granted a project to ascertain the feasibility of some Bb strains as possible alternative sources of hydrocarbons; • The aim of the research was to:
– Determine the environment tolerance of Bb – Demonstration of the successful culture method of Bb – Examine the link between oil content of Bb and environmental factors.
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BIODIESEL AND ALGAE CULTIVATION
Peking University announces to have set-up a new pyrolysis process to produce directly bio-oil from algal biomass; Oil yield is 18 – 24 % of biomass weight (dry basis) and depends on the various kinds of algae utilised.
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BIO – ETHANOL AS POWER ALCOHOL (1)
Bio-ethanol (BETOH) is, at present, the most used and considered renewable liquid fuel able to integrate or replace the crude; Some figures are necessary to better understand the role of biomass from agriculture activities because it is the raw material for BETOH production.
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BIO – ETHANOL AS POWER ALCOHOL (2)
Vegetable kingdom annually produces about 200 billions tons of dry organic materials converting solar energy via photosynthesis.
From the practical point of view, to avoid desertification, energy stored in organic material can be used if the vegetative environment is preserved or restored using the cyclic process of agriculture.
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BIOMASS FOR BETOH
The most important biomasses to produce BTEOH are starchy and lignocellulosic ones.
LIGNOCELLULOSE This material is wood derived both as primary culture and /or agriculture by-products. In order to extract fermentable sugars from lignocellulose, it is necessary to pre-treat, as first, the raw material by physical and/or chemical treatments followed by enzymes hydrolysis of the alone cellulose.
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BIOMASS FOR BETOH (2)
From cellulose than it is possible to obtain a sugary juice ready for feeding alcoholic fermentation and to produce BETOH.
At present, lignocellulosic materials are under a very strong R&D activity mainly in order to have:
• • • • a minor chemicals addition; a valorisation of lignin to improve the process economics; a cheaper cost of all enzymes involved in the pre-treatment process a cheaper cost of woody materials
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BETOH FIRST CONCLUSION
Lignocellulosic material will play an important role for BETOH production in a medium term after solving the above mentioned improvements
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STARCHY MATERIALS
All cereals , mainly corn, soft wheat and sweet sorghum are intensively utilised to produce BETOH worldwide;
Starch from these grains is easy hydrolysed by enzymes to obtain a glucose syrup subsequently converted by fermentation into Bio-Ethanol; Europe, USA, Brazil and China have available very advanced fermentation processes; recently China setup the so called FAST FERMENTATION during more or less 5-6 hours.
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GENERAL GEOPOLITICAL CONSIDERATION
European Union (EU), at present produces more than 1.6 million tons of BETOH a year; Brazil, USA, EU25, Asia, Mexico and Canada produce 10; 8; 1.6; 1.6; 1.3; 1.0; 1.0 BETOH tons (anhydrous) a year respectively; As raw material, Brazil utilise sugar cane while USA corn; Only on 2005, USA already realized ten complete new plants for anhydrous BETOH production with a potentiality of 100.000 tons/year/plant
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ECONOMICS CONSIDERATIONS (1)
On this aspect there are two main current opinions: FIRST OPINION When the crude price vas around 20 US $/barrel, in the States the production cost of BETOH per gallon was 1.20 $ : 0.66 as net cost and 0.54$ as Government support. Now, at the present, crude price is over 60$/barrel and, on the basis of figures above mentioned, the anhydrous BETOH production cost should be more convenient than the crude itself and without any Government’s subsidy.
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ECONOMICS CONSIDERATIONS (2)
SECOND OPINION Farming and industrial analysis in terms of enthalpy and exenergy balance indicates that the main energy cost for fuel BETOH production are due to farming.
A breakdown of the agricultural energy costs indicates that the energy used for the production of fertilisers is the main component in the farming balance.
BETOH could be considered an energy sources only if the energy costs in agricultural production of the biomass are significantly reduced.
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ECONOMICS CONSIDERATIONS (3)
But even with a reduction of about 35% in the subsidiary energy, the net energy gain is lower than the energy costs (half in terms of enthalpy and one third in terms of exenergy). Some exenergy analysis performed in parallel with the enthalpy analysis gives results that are less optimistic. One Ha of land produces about 7 tons of corn grains, equivalent to 2,730 l of BETOH, i.e., 60 GJ of enthalpy (1,55 Toe) or 20 GJ of exenergy. The market value of BETOH based on $40/barrel of crude is about $250, less than half a farmer earns by selling the corn as food.
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BIOMETHANE
Bio-methane or, more recently, BIOGAS is probably the oldest form of renewable energy produced from biomass. At the basis of biogas production there is an anaerobic fermentation performed by some bacteria having more or less three billion years. The increasing role of anaerobic fermentation is due to the fact that, generally, it is applied successfully to treat different kind of organic wastes, solid, semisolid an liquid helping to solve contemporaneously the pollution problems associated to these wastes.
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BIOMETHANE (2)
Biogas production can be now considered as an high value by-product of different anaerobic bio-treatments of organic pollution with economic benefits for energy balance of industry, wastewater treatment platforms, Municipal solid wastes, animal farming, etc. Biogas normally is utilised as fuel to feed co-generation apparatus supplying electrical energy and hot water.
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