Methodology and application of algae as biofuel

METHADOLOGY AND APPLICATION OF ALGAE AS BIOFUEL 2013-2014

CHAPTER - 1

INTRODUCTION

The global economy is massively dependent on fossil fuels and the every growing nation is

becoming increasingly dependent upon foreign sources of crude oil.. The rising energy demand

in many rapidly developing countries around the world is beginning to create intense competition

for the world’s dwindling petroleum reserves. Furthermore, the combustion of petroleum-based

fuels has created serious concerns about climate change from the greenhouse gas (GHG)

emissions which is responsible for the global warming. In recent times all the growing nation

have new standards for vehicle fuel economy, as well as made provisions that promote the use

of renewable fuels, energy efficiency, and new energy technology research and development.

For these reasons since a couple of years there is a lot of researches in progress for

ALTERNATIVE FUEL like BIOFUEL

DEPARTMENT OF MECHANICAL ENGINEERING-RRCE Page 1


BIOFUEL

The first generation of bio fuels is ethanol made out of crops. This kind of fuels has, like

fossil fuels, also many disadvantages. First of all it needs agricultural space for its cultivation.

This means that it is in competition with the arable land for human nutrition. The consequences

of this competition are the scarcity of food and the increasing of the world food prices. One of

the goals of producing and using crop bio fuels was the reducing of greenhouse gas emissions

due to burning fossil fuels. The idea behind is that the released CO2 due to burning bio fuels is

rebounding by crop growth through the mechanism of photosynthesis. But the hole gaining

process of ethanol from crops consumes a lot of energy (mostly from fossil fuels). First of all the

industrial cultivation and harvesting needs machines operating by fossil fuels. Then the

transformation from plants to ethanol is also energy intensive

The second generation of biofuels was made out of residues from crops, animals, timber and

food. This application reduces the disadvantage competition with human food. But the crop

residues are an essential source of nutrients for plants. Burning these crop residues means

decreasing of organic matter in agricultural soils and using more mineral fertilizer like

ammonium which is made under high energy use.

Now the third generation of biofuels is developing. In a very short abstraction it is biofuel

made directly by algae i.e. microalgae (microorganisms).



WHAT ARE ALGAE?

Algae range from small, single-celled organisms to multi-cellular organisms, some with fairly

complex and differentiated form. Algae are usually found in damp places or bodies of water and

thus are common in terrestrial as well as aquatic environments. Like plants, algae require

primarily three components to grow: sunlight, carbon-dioxide and water. Photosynthesis is an

important bio-chemical process in which plants, algae, and some bacteria convert the energy of

sunlight to chemical energy.

The existing large-scale natural sources are of algae are bogs, marshes and swamps - salt

marshes and salt lakes. Micro-algae contain lipids and fatty acids as membrane components,

storage products, metabolites and sources of energy. Algae contain anything between 2% and

40% of lipids/oils by weight.

ADVANTAGES OF ALGAL FEED STOCKS

There are several aspects of algal bio fuel production that have combined to capture the interest

of researchers and entrepreneurs around the world:

• Algal productivity can offer high biomass yields per acre of cultivation.



• Algae cultivation strategies can minimize or avoid competition with arable land and nutrients

used for conventional agriculture.

• Algae can utilize waste water, produced water, and saline water, thereby reducing competition

for limited freshwater supplies.

• Algae can recycle carbon from CO2-rich flue emissions from stationary sources, including

power plants and other industrial emitters.

• Algal biomass is compatible with the integrated biorefinery vision of producing a variety of

fuels and valuable co-products.

CHAPTER - 2

METHADOLOGY OF ALGAE FUEL

The commercial-scale production of algae requires careful consideration of many issues that can

be broadly categorized into four main areas: selecting algae species that produce high oil levels



and grow well in specified environments, water source and issues algae growth methods, and

nutrient and growth inputs.





1. SELECTING ALGAE SPECIES

Research into algae for the mass-production of oil focuses mainly on microalgae (organisms

capable of photosynthesis that are less than 0.4 mm in diameter, including the

diatoms and cyanobacteria) as opposed to macroalgae, such as seaweed. The preference for

microalgae has come about due largely to their less complex structure, fast growth rates, and

high oil-content (for some species). However, some research is being done into using seaweeds

for biofuels, probably due to the high availability of this resource.

Genetically modified strains of algae are being developed for algae biofuels, especially high

lipid-content algae. Certain companies have developed algae strains with unique characteristics .

ADVANTAGES OF MICROALGAE:

(1) Microalgae are capable of all year round production, therefore, oil productivity of microalgae

cultures exceeds the yield of the best oilseed crops, e.g. biodiesel yield of 12,000 l ha_1 for

microalgae (open pond production) compared with 1190 l ha_1 for rapeseed .

(2) They grow in aqueous media, but need less water than terrestrial crops therefore reducing the

load on freshwater sources .

(3)Microalgae can be cultivated in brackish water and therefore may not incur land-use change,

minimizing associated environmental impacts . while not compromising the production of food,

fodder and other products derived from crops.

(4) Microalgae have a rapid growth potential and many species have oil content in the range of

20–50% dry weight of biomass, the exponential growth rates can double their biomass in periods

as short as 3.5 h .

(5) With respect to air quality maintenance and improvement, microalgae biomass production

can effect bio fixation of waste CO2 (1 kg of dry algal biomass utilize about 1.83 kg of CO2) .

(6) Nutrients for microalgae cultivation(especially nitrogen and phosphorus) can be obtained

from wastewater, therefore, apart from providing growth medium, there is dual potential for

treatment of organic effluent from the agri-food industry ;

(7) Algae cultivation does not require herbicides or pesticides application .



(8) They can also produce valuable co-products such as proteins and residual biomass after oil

extraction, which may be used as feed or fertilize , or fermented to produce ethanol or methane ;

(9) The biochemical composition of the algal biomass can be modulated by varying growth

conditions , therefore, the oil yield may be significantly enhanced , and

(10) Microalgae are capable of photobiological production of ‘biohydrogen’. The outlined

combination of potential biofuel production, CO2 fixation, biohydrogen production,and bio-

treatment of wastewater underscore the potential applications of microalgae.

2. GROWTH INPUTS

LIGHT

Algae generally require light to grow. If the primary light source is natural sunlight, it

may be advisable to secure solar rights, for the project site. Many companies are developing

systems and technologies using artificial light sources. OriginOi l has developed a Helix

BioReactorTM that features a rotating vertical shaft with low-energy lights arranged in a helix

pattern.

HIGH TEMPERATURE AND PRESSURE

An alternative approach employs a continuous process that subjects harvested wet algae to high

temperatures and pressures—350 °C (662 °F) (662 °F) and 3,000 pounds per square inch

(21,000 kPa).

NUTRIENTS

Nutrients like nitrogen (N), phosphorus (P), and potassium (K), are important for plant growth

and are essential parts of fertilizer. Silica and iron, as well as several trace elements, may also be

considered important marine nutrients as the lack of one can limit the growth of, or productivity

in, an area.

CARBON DIOXIDE

Bubbling CO2 through algal cultivation systems can greatly increase productivity and yield (up

to a saturation point). Typically, about 1.8 tonnes of CO2 will be utilized per tones of algal



biomass (dry) produced, though this varies with algae species.. Each tones of microalgae absorbs

two tonnes of CO2.

NITROGEN

Nitrogen is a valuable substrate that can be utilized in algal growth. Various sources of nitrogen

can be used as a nutrient for algae, with varying capacities. Nitrate was found to be the preferred

source of nitrogen, in regards to amount of biomass grown. Urea is a readily available source that

shows comparable results, making it an economical substitute for nitrogen source in large scale

culturing of algae.Despite the clear increase in growth in comparison to a nitrogen-less medium,

it has been shown that alterations in nitrogen levels affect lipid content within the algal cells.

WASTEWATER

A possible nutrient source is waste water from the treatment of sewage, agricultural, or flood

plain run-off, all currently major pollutants and health risks. However, this waste water cannot

feed algae directly and must first be processed by bacteria, through anaerobic digestion..

The utilization of wastewater and ocean water instead of freshwater is strongly advocated due to

the continuing depletion of freshwater resources. However, heavy metals, trace metals, and other

contaminants in wastewater can decrease the ability of cells to produce lipids biosynthetically

and also impact various other workings in the machinery of cells. The same is true for ocean

water, but the contaminants are found in different concentrations.

3. CULTIVATION

PRINCIPLE

Algae grows naturally in fresh, brackish, or salt water, depending on the algae species. Under

natural growth conditions algae absorb sunlight, and assimilate carbon dioxide from the air and

nutrients from the aquatic habitats. Therefore, as far as possible, artificial production should

attempt to replicate and enhance the optimum natural growth conditions.

Three distinct algae production mechanisms including photoautotrophic, heterotrophic and

mixotrophic production, all of which follow the natural growth processes.



PHOTOAUTOTROPHIC PRODUCTION

Currently, photoautotrophic production is the only method which is technically and economically

feasible for large-scale production of algae biomass for non-energy production .

Two systems that have been deployed are based on open pond and closed photobioreactor

technologies . The technical viability of each system is influenced by intrinsic properties of the

selected algae strain used, as well as climatic conditions and the costs of land and water .

OPEN POND PRODUCTION SYSTEMS

These systems can be categorised into natural Algae cultivation in open pond production systems

has been used waters (lakes, lagoons, and ponds) and artificial ponds or containers.

Raceway ponds are the most commonly used artificial system .They are typically made of a

closed loop, oval shaped recirculation channels (Fig. 1), generally between 0.2 and 0.5mdeep,

with mixing and circulation required to stabilize algae growth and productivity.



Raceway ponds are usually built in concrete, but compacted earth lined ponds with white plastic

have also been used. In a continuous production cycle, algae broth and nutrients are introduced

in front of the paddlewheel and circulated through the loop to the harvest extraction point. The

paddlewheel is in continuous operation top revent sedimentation. The microalgae’s CO2

requirement is usually satisfied from the surface air, but submerged aerators may be installed to

enhance CO2 absorption.

Compared to closed photo bioreactors , open pond is the cheaper method of large-scale algal

biomass production. Open pond production does not necessarily compete for land with existing

agricultural crops, since they can be implemented in areas with marginal crop production

potential. They also have lower energy input requirement and regular maintenance and cleaning

are easier and therefore may have the potential to return large net energy production

Fig. . Plan view of a raceway pond. Algae broth is introduced after the paddlewheel, and completes a cycle while

being mechanically aerated with CO2. It is harvested before the paddlewheel to start the cycle again (adapted from

Chisti ).

CLOSED PHOTOBIOREACTOR SYSTEMS

Microalgae production based on closed photobioreactor technologies designed to overcome

some of the major problems associated with the described open pond production systems. For

example,pollution and contamination risks with open pond systems, for the most part, preclude

their use for the preparation of high-value products for use in the pharmaceutical and cosmetics

industry. Closed systems include the tubular, flat plate, and column photobioreactor. These

systems are more appropriate for sensitive strains as the closed configuration makes the control

of potential contamination easier. Owing to the higher cell mass productivities attained



harvesting costs can also be significantly reduced. However, the costs of closed systems are

substantially higher than open pond systems.

Photobioreactor consist of an array of straight glass or plastic tubes as shown in Fig. The tubular

array captures sunlight and can be aligned horizontally, vertically, inclined or as a helix and the

tubes are generally 0.1 m or less indiameter

Fig.. Basic design of a horizontal tubular photobioreactor (adapted from Becker Two main sections: airlift system

and solar receiver; the airlift systems allow for the transfer of O2 out of the systems and transfer of CO2 into the

system as well as providing a means to harvest the biomass. The solar receiver provides a platform for the algae to

grow by giving a high surface area to volume ratio.

Algae cultures are re-circulated either with a mechanical pump or airlift system, the latter

allowing CO2 and O2to be exchanged between the liquid medium and aeration gas as well as

providing a mechanism for mixing. Agitation and mixing are very important to encourage gas

exchange in the tubes. The reactors are made of transparent materials for maximum solar energy

capture, and a thin layer of dense culture flows across the flat plate which allows radiation

absorbance in the first few millimeters thickness. Closed photobioreactor have received major

research attention in recent years.

HYBRID PRODUCTION SYSTEMS



The hybrid two-stage cultivation is a method that combines distinct growth stages in photo

bioreactors and in open ponds.

HETEROTROPHIC PRODUCTION

In this process microalgae are grown on organic carbon substrates such as glucose in stirred tank

bioreactors or fermenters and independent of photosynthesis

MIXOTROPHIC PRODUCTION

Many algal organisms are capable of using either metabolism process (autotrophic or

heterotrophic) for growth, meaning that they are able to photosynthesise as well as ingest prey or

organic materials .

4. HARVESTING ALGAE AND DEWATERING

Generally, microalgae harvesting is a two stage process, involving:



(1) BULK HARVESTING—aimed at separation of biomass from the bulk suspension.

This will depend on the initial biomass concentration and technologies employed, including

flocculation, flotation or gravity sedimentation.

(2)THICKENING - the aim is to concentrate the slurry through techniques such as

centrifugation, filtration and ultrasonic aggregation, hence, is generally a more energy intensive

step than bulk harvesting.

Method Description Materials Advantages Disadvantages References

Centrifugation

Mechanical method that removes water by centrifugal force

Centrifuge

High recovery rate, high rate of solids, no contamination by chemicals

High energy requirement, damage to cells by shearing

Filtration

Algae passes through membrane that retains the solids while the media passes through

Filter, suction pump

High recovery rate, lower energy requirement, no contamination by chemicals

Redilution (dewatering) may be required, fouling of filter membrane may occur

Flocculation

Aggregation of cells is caused by removing the electrostatic barrier that separates them

Flocculant, such as NaOH, chitosan, aluminum chloride

Less damaging than centrifugation, low energy requirements, efficient

Contamination of harvested algae with chemicals, hard to flocculate saltwater algae

Flotation

Algae is floated to the surface using bubbling, and skimmed off the surface, often in combination with flocculation

Flocculant, gas impeller, collection bowl

No damage to cells, simple, low energy

May not work well for dense cultures

Ultrasonic separation

Sound waves cause the cells to agglomerate

Ultrasonic wave generator,

Removal of most water, no damage to cells,

High energy input, high cost, cells not as



resonator chamber, pump

no fouling of system

concentrated as other harvesting methods

Electrolytic methods

Electrodes cause coagulation of cells so that they fall out of suspension

Electrodes

Low energy input, no contamination, media can be recycled

Electrodes may foul

Flocculation

Since microalgae cells carry a negative charge that prevents natural aggregation of cells in

suspension, addition of flocculants such as multivalent cations and cationic polymers neutralizes

or reduces the negative charge. It may also physically link one or more particles through a

process called bridging, to facilitate the Multivalent metal salts like ferricchloride (FeCl3),

aluminium sulphate (Al2(SO4)3) and ferric sulphate (Fe2(SO4)3) are suitable flocculants.

Ultrasound

Gentle, acoustically induced aggregation followed by enhanced sedimentation can also be used

to harvest microalgae biomass..The main advantages of ultrasonic harvesting are that it can be

operated continuously without inducing shear stress on the biomass, which could destroy

potentially valuable metabolites, and it is a non-fouling technique.



Figure Schematic of an ultra filtration unit

Harvesting by flotation

Flotation methods are based on the trapping of algae cells usingdispersed micro-air bubbles and

therefore, unlike flocculation, does not require any addition of chemicals

Gravity and centrifugal sedimentation

Gravity and centrifugation sedimentation methods are basedon Stoke’s Law i.e. settling

characteristics of suspended solids is determined by density and radius of algae cells

(Stoke’sradius) and sedimentation velocity

Biomass filtration

A conventional filtration process is most appropriate for harvesting of relatively large (>70 mm)

microalgae .It cannot be used to harvest algae species approaching bacterial dimensions (<30

mm) .

Dehydration processes

The harvested biomass slurry (typical 5–15% dry solid content)is perishable and must be

processed rapidly after harvest; dehydration or drying is commonly used to extend the viability

depending on the final product required. Methods that have been used include sun drying low-



pressure, shelf drying, spray drying, drum drying, fluidized bed drying, freeze drying], and

Refractance Window TM technology drying .

5. EXTRACTION

After the cells are harvested, lipids must be extracted from the cells. In order to accomplish this,

cell walls must be disrupted without extracting other components. Like harvesting, there are

mechanical, chemical, and physical methods. Methods of extraction are listed in Table .

Method Description Comments

HomogenizationAlgae is expelled through small valves which disrupt the cell walls

Often used as a pretreatment for further extraction, no chemical contamination

Bead MillingAlgae is placed in a chamber with small beads that are agitated and disrupt cells

No chemical contamination

Bligh and Dyer

After determining the water content, sample is homogenized with 2:1 methanol:chloroform, and washed with chloroform and water. Two phases are formed, and the lipid phase is collected.

Not accurate with samples of greater than 2% lipid, originally designed for extraction of phospholipids of fish.

FolchAlgae is mixed with 2:1 chloroform:methanol, allowed to settle into phases. The lipid phase is washed and collected, and then allowed to dry.

Originally designed for extracting lipids from brain tissue. Considered the standard for lipid extraction

Soxhlet A weighed sample is placed in a soxhlet Can be a long process



apparatus, and solvent is added. The lipids are slowly extracted and then dried.

Supercritical

A supercritical fluid is created by adding high pressure and temperature until it has properties of both. It has the density of a liquid and the compressibility of a gas. Algae is placed in an extraction vessel, and the supercritical fluid passes through the vessel and then vents to the atmosphere.

Carbon dioxide is of special interest. Temperature may be used to select for specific lipids because of its effect on solubility.

SonicationBubbles are created by ultrasound, and when they burst, they disrupt cell walls.

No chemical contamination

Subcritical waterWater is heated to boiling, and pressure is applied, creating a solvent.

Mostly used with higher plants

MicrowavesMicrowaves are used to generate energy in polar solvents and remove water in order to disrupt cell walls.

Rapid method

Table. Methods used to extract lipids from microalgae

The soxhlet method uses solvents, as diagrammed in Figure. Unfortunately, most solvent

methods of extraction may contaminate the finished product with unwanted chemicals. The

benefit of mechanical methods is that they leave no unwanted residue.

Figure. A diagram of a soxhlet apparatus.

6. CONVERSION OF ALGAE OIL INTO BIOFUEL



Algae can be converted into various types of fuel, depending on the technique and the part of the

cells used. The lipid, or oily part of the algae biomass can be extracted and converted into

biodiesel through a process similar to that used for any other vegetable oil, or converted in a

refinery into "drop-in" replacements for petroleum-based fuels. Alternatively or following lipid

extraction, the carbohydrate content of algae can be fermented into bioethanol or biobutanol New

technologies like the Mcgyan® Process offer flexible feedstock options that could work well if

an algae biofuels facility was not able to produce enough oil to fully supply a plant.

THERMOCHEMICAL CONVERSION.

Thermochemical conversion covers the thermal decomposition of organic components in

biomass to yield fuel products, and is achievable by different processes such as direct

combustion, gasification, thermochemical liquefaction, and pyrolysis.

GASIFICATION

Gasification involves the partial oxidation of biomass into a combustible gas mixture at high

temperatures (800–1000 8C) .The key advantage of gasification as abiomass-to-energy pathway

is that it can produce a syngas from awide variety of potential feedstocks



Thermochemical liquefaction is a process that can be employedto convert wet algal

biomass material into liquid fuel .

Pyrolysis is the conversion of biomass to bio-oil, syngas andcharcoal at medium to high

temperatures (350–700 8C) in theabsence of air

In a direct combustion process, biomass is burnt in the presenceof air to convert the stored

chemical energy in biomass into hot

gases

The biological process of energy conversion of biomass intoother fuels includes anaerobic

digestion, alcoholic fermentationand photobiological hydrogen production.



Anaerobic digestion (AD) is the conversion of organic wastesinto a biogas, which consists

of primarily methane (CH4) andcarbon dioxide, with traces of other gases such as

hydrogensulphide.

Alcoholic fermentation is the conversion of biomass materialswhich contain sugars, starch

or cellulose into ethanol.

Hydrogen (H2) is a naturally occurring molecule, which is aclean and efficient energy carrier

[163]. Microalgae possess thenecessary genetic, metabolic and enzymatic characteristics

tophotoproduce H2 gas .

Biodiesel is a derivative of oil crops and biomass which can beused directly in conventional

diesel engines .It is a mixture of

monoalkyl esters of long chain fatty acids (FAME) derived from arenewable lipid feedstock such

as algal oil

The last step in the process to creating a viable fuel is to convert the TAG to fatty acid methyl

esters (FAME), the lipids that constitute fuel. The process of converting TAG to FAME is

known as transesterification. In this reaction, a simple alcohol such as methanol is added to

lipids. A catalyst, such as NaOH, can be used. The reaction takes place in a vessel while being

stirred, creating FAME and a glycerol byproduct. If supercritical alcohol is used in the reaction a

catalyst may not be necessary, and also may be used to bypass the extraction method. The

supercritical alcohol method is accomplished by adding methanol to dried algae and heating for



40 minutes at 90º C to cause a supercritical reaction. Mixing helps the separation process.

Finally in producing viable Fuel is to remove the glycerol byproduct, along with any other

contaminant that may be present via gravitational settling or centrifugation.

Algae biofuels plants will generally produce a new type of fuel that has not yet been

commercialized, and the plant backers will need to clear significant hurdles to achieve success.

It is in recognition of these challenges that the federal government policy supports advanced

biofuels that conform to existing specifications and serve as a substitution for petroleum-based

fuels. Typically the ASTM International, a private organization, is the primary deliberative body

defining fuel specifications



CHAPTER - 3

APPLICATION OF ALGAE AS BIOFUEL

BIODIESEL

Biodiesel is a diesel fuel derived from animal or plant lipids (oils and fats). Studies have shown

that some species of algae can produce 60% or more of their dry weight in the form of oilbecause

the cells grow in aqueous suspension, where they have more efficient access to water, CO2 and

dissolved nutrients, microalgae are capable of producing large amounts of biomass and usable oil

in either high rate algal ponds or photobioreactors. This oil can then be turned

into biodiesel which could be sold for use in automobiles.

The U.S. Department of Energy's Aquatic Species Program, 1978–1996, focused on biodiesel

from microalgae. The final report suggested that biodiesel could be the only viable method by

which to produce enough fuel to replace current world diesel usage.

BIOBUTANOL

\Butanol can be made from algae or diatoms using only a solar powered biorefinery. This fuel

has an energy density 10% less than gasoline, and greater than that of eitherethanol or methanol

BIOGASOLIN

Biogasoline is gasoline produced from biomass. Like traditionally produced gasoline, it contains

between 6 (hexane) and 12 (dodecane) carbon atoms per molecule and can be used in internal-

combustion engines.\

METHANE

Methane the main constituent of natural gas can be produced from algae in various methods,

namely Gasification, Pyrolysis and Anaerobic Digestion microalgae cultivation operations, it has

been proposed to recover the energy contained in waste biomass via anaerobic digestion to

methane for generating electricity



ETHANOL

The Algenol system which is being commercialized by BioFields in Puerto Libertad, Sonora,

Mexico utilizes seawater and industrial exhaust to produce ethanol. Porphyridium cruentum also

have shown to be potentially suitable for ethanol production due to its capacity for accumulating

large amount of carbohydrates

HYDROCRACKING TO TRADITIONAL TRANSPORT FUELS

Algae can be used to produce 'green diesel' (also known as renewable diesel, hydro-treated

vegetable oil or hydrogen-derived renewable diesel) through a hydrocracking refinery process

that breaks molecules down into shorter hydrocarbon chains used in diesel engines. It has the

same chemical properties as petroleum-based dieselmeaning that it does not require new engines,

pipelines or infrastructure to distribute and use. It has yet to be produced at a cost that is

competitive with petroleum.

JET FUEL

Rising jet fuel prices are putting severe pressure on airline companies creating an incentive for

algal jet fuel research. The International Air Transport Association, for example, supports

research, development and deployment of algal fuels. IATA's goal is for its members to be using

10% alternative fuels by 2017Trials have been carried with aviation biofuel by Air New

Zealand, Lufthansa, and Virgin Airlines



CHAPTER - 4

CONCLUSION

This seminar underlines the existing technical viability for the development of biofuels from

microalgae as a renewable energy resource and for mitigation of GHG related impacts of

petroleum derived fuels. The achievable high yields for both lipids and biomass, combined with

some useful co-products if purposefully exploited, could enhance algae’s economic viability as a

source for biofuels. Phototrophic production is the most effective in terms of net energy balance.

However, productivity values vary immensely and are significantly lower when compared with

heterotrophic production.

The use of waste CO2 from power plants to enhance production has been shown to be

technically feasible, and hence, may be deployed to reduce production costs and for GHG

emission control. Harvesting of algal biomass accounts for the highest proportion of energy input

during production. Lipids are the most readily extractible biofuel feedstock from algae, but

potential storage is hindered by the presence of polyunsaturated fatty acids(PUFAs) causing

oxidation reactions and high moisture content of algal feedstock. This seminar also suggests that

both thermochemical liquefaction and pyrolysis appear to be the most technically feasible

methods for conversion of algal biomass-to-biofuels, after the extraction of oils from algae..

Overall, with the current demand for renewable fuels, especially for use in the transportation

sector, there is a need to develop a range of sustainable biofuels resources as the combined mix

will be a significant step towards the replacement of fossil fuels. Continued development of

technologies to optimise the microalgae production, oil extraction and biomass processing has

the capacity to make significant contributions towards this goal.



CHAPTER-5

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Methodology and application of algae as biofuel