microalgae to biodiesel

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    Prof. Roberto Rana

    University of Foggia

    Faculty of Economics

    University of Foggia - Faculty ofEconomicsErasmus Intensive Programme EPROBIO

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    Why to use algae to produce biofuels?

    Over this last decades the frequent oil crises

    and environmental impact of fossil fuels, hasdived many industrialized countries tocarrying out research to discover analternative sources of fuels able to ensure a

    new energy sources supply that reduceemissions of CO2, nitrogen monoxides andsulphur into the atmosphere.

    So, has been introduced biofuels mainlyderived from sugar cane, corn, as bio-

    ethanol or biodiesel, obtained fromrapeseed, soybean, etc. However someresearchers believe that bio-energy will notbe able to satisfy future world fuels

    requirements, since intense energy crop

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    Why to use algae to produce biofuels? Algae are the fastest growing

    microorganisms (some unicellular algaedouble their weight in 12-24 hours, whilecells are able to separate in less than 4hours),

    Algae are most abundant biomassproducers in earths biosphere. Some algaehave a high yield (biomass production) (50-70 t/hectares per year).

    Most algae are unicellular and thereforecontain a very high amount of starches orlipids (up to 50% dw).

    Compared to plants, algae require less

    space to grow, have more tolerant

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    RHODOPHYTA

    Chondrus crispus

    Gelidium spp

    PHAEOPHYTA

    Fucus spp

    Laminaria spp

    Ascophyllum nodosum

    CLOROPHYTAUlva lactuca

    MACROALGAE

    Classification of Algae

    Worldwide are described 30 000 species of microalgae (< 10% of estimated).The classes (29) are distinguished by the structure of flagellate cells (e.g.,

    scales, angle of flagellar insertion, microtubular roots, and striated roots), thenuclear division process (mitosis), the cytoplasmic division process

    (cytokinesis), and the cell covering.

    Spirulina spp flos-aquae

    Diatomee

    (Bacillariophyta)

    MICROALGAE

    Cianoficae Clorophycophyta

    Green algae

    Chrysophycophyta

    (golden algae)

    Dinophyta

    (dinpflagellates)

    Neochlorisoleoabundans,

    Scenedesmus

    dimorphus,

    Botryococcus brunii

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    Macroalgae or seaweeds

    The worlds mostsuccessful seaweedcultivation industriesare in Asia. Howeverthis continent is reallow in technology

    Japan is one ofthe big producer

    and consumer ofseaweeds in the

    world.

    Cultivating seaweed in

    Portugal, England andIreland is traditional.People use fertilizer for

    their seaweed.

    China is thebiggest producer

    and consumer ofseaweed

    The shallow coral

    lagoons off the

    coast of EastAfrica andZanzibar are

    host to multipleseaweed farms.

    Seaweeds cultivation are old. Seaweed has

    been part of the Chinese diet for over 2000years and probably much longer. The macro-algae have a high biomass yield from 7-30t/hectares.

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    Macroalgae growing systems

    There are many

    technologies tocultivate seaweed.For instancetraditionalseaweed farminguses lines, ropes,nets or rafts,floating suspendedin the sea.

    Young seaweed orpart of seaweed

    are attacked to thesubstrate and thanare left to grow for6 to 8 weeks,depending on the

    species andlocation.

    Generally seaweeds species grow

    very fast and can be croppedwithin a few months.

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    A new cultivationsystems of seaweed

    Because most ofmacro algae live onthe sea bed isdifficult to cultivate

    in offshoreinstallations andhave highproduction. These

    technology, indeed,are subjected to theaction of waves andtides. To resolve

    these problemsA concave mirror placed in the sea

    surface converges the radiation at depths

    where macroalgae grow

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    Paths of the various energy products fromseaweedSyngas is the name given to a

    gas mixture that contains

    varying amounts of carbon

    monoxide and hydrogen. Thegas is obtained by a process

    that occurs at high

    temperature and in absence of

    oxygen

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    MICROALGAE

    The microalgae areunicellular

    organisms, in generalphotosynthetic, with

    a few microns size(

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    MICROALGAEMicroalgae generally have a protein,

    carbohydrates and fats content vary widelydepending on the species. For instance

    the average amount of lipid ranges from 1-

    40% dry weight. Fats composition and

    quantity depend on the environmental

    factors of the algae broth (temperature,

    salinity, light intensity, etc.). So, when algal

    cells grow in situations of nutrientdeficiency (such as nitrogen, silicon, etc.)

    or in a broth rich in sodium chloride, can

    increase fats content more than 70%.

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    Microalgae

    Biodiesel

    Hydrogen

    Bio-ethanol Biogas

    Foodsuppleme

    nts

    Food

    industry

    Feed

    industry

    FinalChemicals

    Commercial use of microalgae

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    BIODIESEL FROM MICROALGAE

    Microalgae, have the highest biomassproduction (50-70 t/ha) and oil content

    (about 20-30 m3/ha) among all plants,

    significantly higher than those of corn,soybeans, palm oil, etc..

    According to some authors, the annual

    yields are much higher, up to values

    280t/ha.

    Comparison between yield of most common

    oleaginous crops and microalgae

    Land surface

    occupied by soy

    productionnecessary to supply

    USA diesel

    consumptionLand surface

    occupied by corn

    production

    necessary to supply

    USA dieselconsumption

    Land surface

    occupied by algae

    schemes necessary

    to supply USAdiesel consumption

    ~ 250 billion liters of diesel is the nation presently consumes

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    BIODIESEL FROM MICROALGAE

    Although the idea of growing algae to obtain biofuels started to

    the end of the 1940s, the first applied studies were

    undertaken only twenty years later, when some American

    researchers proposed to use these organisms to obtain biogas

    by fermentation, to be burned in electric power plants.

    During the first energy crisis (1973) the American Congress

    set up the NREL (National Renewable Energy Laboratory),linked to the DOE (Department Of Energy). This laboratory

    carried out a programme, call Aquatic Species Program

    (ASP), to grow unicellular microalgae in a ponds connected to

    electric power plants.

    but thisprogramme wasstoped in 1996

    because

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    BIODIESEL FROM MICROALGAE

    Initially DOE researchers was aimed at the possibility to

    obtain biogas from the fermentation of microalgae and to

    store CO2. The success of this experiment and the

    discovery of large quantities of oil contained in

    microalgae led researchers to use these organisms to

    produce biodiesel.

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    1Open ponds

    2Photobioreactors

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    Open cultivation systems

    Open pond or racewaypondA raceway pond is a shallow

    artificial pond used in the

    cultivation of algae. The pond,

    with a surface from 100-1000-

    10000 m2

    and a dept from 15-30cm, is divided by several baffles

    forming one channel in the

    shape of an oval, like an

    automotive raceway circuit. From

    above, many ponds look like a

    maze (labyrinth). Each basin

    contains a paddlewheel to make

    the water flow continuously

    around the circuit and prevents

    the deposition of microalgae on

    the bottom of the pond.

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    Open cultivation systems

    Open pond or racewaypond

    To cultivate microalgae requires an appropriate culture

    medium (broth), consisting of an aqueous solution rich in

    inorganic salts such as sodium chloride, potassium

    carbonate, calcium chloride, potassium nitrate, calciumphosphate, etc.. and appropriate environmental conditions

    (light, temperature, concentration of CO2, etc.).

    Some installations are made by several pondswhere you can use a thermal power plantemissions (CO2, and oxides of nitrogen) and/or

    sewage(wastewater with high concentration ofnitro en and hos horus to feed al ae.

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    Open cultivation systems

    To prevent predation by other species, the salt

    concentration of the broth is keep high

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    In order to cultivate microalgae species thatprefer lower salt concentrations, achieving

    a higher cell density and prevent the

    contamination of culture medium, were

    tested the photobioreactors.These facilities are closed systems in which

    the algae are not direct contact with the

    external environment and receive solar

    radiation direct