Dayananda Sagar College of Engineering
Department of Chemical Engineering
Presented by :- PIYUSH KUMAR
Seminar on :- Algae-Biofuel
16-Mar-16DSCE CHEMICAL ENGG. 1
Why algae fuel?
Comparison of Oil yields
Other uses of algae
16-Mar-16DSCE CHEMICAL ENGG. 2
Algae (Latin: seaweed) are prokaryotic or eukaryotic photosynthetic microorganisms
that can grow rapidly and live in harsh conditions due to their unicellular or simple
Autotrophic: Organisms that produce complex organic compounds from simple
inorganic molecules using energy from light (photosynthesis)
Algae are dated back to approximately 3 billion years in the Precambrian age (4600 Ma
to 542 Ma; 88% of geological time).
The first plants on earth evolved from shallow freshwater algae.
16-Mar-16DSCE CHEMICAL ENGG. 3
Biofuels – the green alternative :
Derived form biological materials through biomass conversion
Production requires more effort and resources
Can significantly reduce greenhouse gas emissions
1. Release CO2 when burning
2. Biofuel production consumes it back.
Types: • Ethanol
• Bio gasoline
• Bio butanol
• Jet fuel
16-Mar-16DSCE CHEMICAL ENGG. 4
Evolution of Biofuel Production :-
16-Mar-16DSCE CHEMICAL ENGG. 5
Why Algae Fuel ?
Can be grown on marginal lands useless for ordinary crops .
High yield per acre – have a harvesting cycle of 1–10 days .
Can be grown with minimal impact on fresh water resources .
Can be grown using flue gas from power plants as a CO2 source .
Can convert a much higher fraction of biomass to oil than conventional crops, e.g. 60%
versus 2-3% for soybean.
No competition with food supply.
16-Mar-16DSCE CHEMICAL ENGG. 6
Comparison of Oil Yields :-
Yields ( Gallons of oil per acre per year )
Oil Palm 635
Micro Algae 5000-15000
16-Mar-16DSCE CHEMICAL ENGG. 7
16-Mar-16DSCE CHEMICAL ENGG. 8
Algae Cultivation :-
Algae Cultivation systems
Currently, two main systems for algae cultivation widely adopted are :-
• Open ponds (raceways)
• Photobioreactors (PBR)
Open ponds Photobioreactors
16-Mar-16DSCE CHEMICAL ENGG. 9
Open pond :-
Algae is cultivated in ponds which are exposed to open air.
Mostly uses environmental carbon dioxide.
Open ponds are the most widely used system for large- scale outdoor microalgae
low cost method but needs plenty amount of water.
Subject to contamination from predator strains
Subject to evaporative water loss
Subject to a difficult control of temperature (day/night, seasonal)
Lead to solutions with little biomass concentration
Require larger amount of nutrients (N, P)
16-Mar-16DSCE CHEMICAL ENGG. 10
Made up of Plastic or borosilicate glass tubes that are exposed to sunlight.
Allow single species culture
Allow easier and accurate provision of nutrients (N, P)
Lead to more concentrated solutions
Need larger amounts of energy for mixing and to maintain temperature
With flue gases (having an higher CO2 concentration than the atmosphere)
Provides carefully controlled artificial environment and specific conditions to algae.
Biomass could be derived from nutrient- rich wastewater and flue gas carbon dioxide in a
16-Mar-16DSCE CHEMICAL ENGG. 11
The harvesting process occurs through a number of steps
•Use of chemical binding agents and air flotation (established solution for sewage
systems) in order to collect biomass. Eg FeCl3
• Process used after flocculation, to reduce the amount of water (de-watering)
• Mechanical process well established in industry, it enhances the concentration
and may destroy the cell wall, leading to a difficult extraction of oils. As a
result, appropriate strains would need to be developed
Flocculation, filtration about 3% concentration in water
Centrifugation about 20%
Further concentration of the biomass is required for the oil extraction through conventional
16-Mar-16DSCE CHEMICAL ENGG. 12
Harvested algae contain 97%-99% water.
Removal of most of the water is necessary for long term storage of the algae feedstock
and is required for many downstream processes.
To keep algae from prolonged microbial growth, the moisture level of the harvested
algae should be kept below 7%.
Drying is an energy intensive process and can account for up to 30% of the total
Natural drying (solar and wind) is the most economical way; however, its weather
dependent nature could easily put the operation at risk of spoilage.
It also requires a large space.
16-Mar-16DSCE CHEMICAL ENGG. 13
Pressing oil from the algae:-
Dry the algae and press the oil from it , can retrieve up to 70% of the oil
simplest and cheapest method
Chemical Oil Extraction :-
Use Hexane solvent to remove the oil .
Super Critical Oil Extraction :-
Most efficient method , uses CO2 at critical pressure and temperature
causing rapid diffusion of the oil , very expensive process.
16-Mar-16DSCE CHEMICAL ENGG. 14
Other uses of algae :-
Microalgae are used as human nutrition, animal feed, aquaculture etc.
Algal biomass contains 20%-40% protein, 30%-50% lipid, 20% carbohydrate, and 10%
Depending on the conversion processes, a range of products can be obtained from algal
16-Mar-16DSCE CHEMICAL ENGG. 15
Conclusion Algae Biofuel is a very promising candidate to replace fossil fuels
Algae’s cultivation does not require that it compete with food crops
Ability for algae to be cultivated on non-arable land, using saltwater, greatly reduces its
impact on the environment
Algae is easy to grow. Can produce a high yield of oil.
Further research necessary to unlock full potential of algae
Help to solve dependence on fossil fuels can be better for the Earth.
16-Mar-16DSCE CHEMICAL ENGG. 16
Research Papers • Ben, A., Amotz , Large Scale Open Algae Ponds, The National Institute of
Oceanography Nature Beta Technologies Ltd. Nikken Sohonsha Co, Japan Seambiotic Ltd.
ISRAEL • Eleazer ,P. R. , Lisa, M. C. , Mark, A. White , Andres F. C., 2012,
Comparison of algae cultivation methods for bioenergy production using a combined life
cycle assessment and life cycle costing approach, Bioresource Technology 126 (2012) 298–
306 • Jorquera, O., Kiperstok, A., Sales, E.A., Embiruçu, M., Ghirardi, M.L., 2010.
Comparative energy life-cycle analyses of microalgal biomass production in open ponds and
photobioreactors. Bioresource Technology 101, 1406–1413.
16-Mar-16DSCE CHEMICAL ENGG. 17