Growing Chlorella for Algae-Oil Biofuels
and Aquaculture Feeds
Aquaculture Sustainability Conference
Yantai, China
Kevin Fitzsimmons and George Lin
Chlorella for Biofuel and Aquaculture Feed
Chlorella cell
Chlorella raceway in Arizona
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Chlorella for Biofuel and Aquaculture Feed
• Lipids (oil
droplets) form
in several types
of algae, but
greens, can be
harvested and
easily
transformed to
biodiesel.
Chlorella for Biofuel and
Aquaculture Feed
• Several species of Chlorella with
varied production
characteristics
• Some species and strains can
produce 60,000 – 100,000 liters
per hectare of algae biomass
• 40% of this biomass can be oil
• Oil (long chain fatty acids) can
be easily converted to diesel
fuel
Chlorella from a raceway culture in Arizona
Chlorella strains and species in cold storage
4
Photobioreactor Design
Scale Up
Investigations:
Flow Velocity
Sparging Rate
Mixing Rate
Initial Density
Light Levels
Nutrients
CO2
Photobioreactor Design
Heigth/Depth
ratios
Flow Velocity
Bubble Size
Mixing Rate
Initial Density
Light Levels
Photobioreactor Designs
ARID Integrated Algae-Oil Biorefinery
Bioreactor
with
Chlorella
in Beijing
Chlorella raceways in Arizona
Raceways
in
Jeddah,
Saudi
Arabia
with
Chlorella
Algae tanks at ERLab, Tucson
Raceways in Puerto
Peñasco, Mexico
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Chlorella for Biofuel and Aquaculture Feed
Chlorella culture in greenhouse bioreactor, Beijing
Chlorella for Biofuel and Aquaculture Feed
• Bioreactor and
raceway
production
Chlorella for Biofuel and Aquaculture Feed
• Production
problems
• Contamination
with nontarget algae
• Introduction
of grazers
• Self shading or
limiting
nutrients
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Chlorella for Biofuel and Aquaculture Feed
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Chlorella for Biofuel and Aquaculture Feed
15
Chlorella for Biofuel and Aquaculture Feed
• Problems with harvest
• Batch harvest or
continuous
• Screen
• Flocculation
• Electrostatic
• Centrifugation
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Harvesting
Chlorella for Biofuel and Aquaculture Feed
• Rotating screen filters
• Water passes through,
how much algae can
be caught in:
60 µm screen?
20 µm screen?
5 µm screen?
ARID Integrated Algae-Oil Biorefinery
18
Chlorella for Biofuel and Aquaculture Feed
• Separation of oil from
algae cells
•
•
•
•
Mechanical press
Hexane extraction
Supercritical CO2
Sonication
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Oils found in Greenhouse culture of Chlorella
• Found in many algal
species
• Essential part of the
nutritional
requirement of
almost all organisms
Super Critical CO2 Pressure Pulse Cracking of Algae Cells
Advantages of ScCO2
Green technology - alternate to use of harmful solvents
Synergy - CO2 vapor can be used to feed the algae
Efficiency - Anticipated efficiencies as high as 95% for algae oil extraction
Proven - for other technologies, ex. Caffeine extraction
Improvement - Downstream process is anticipated to be enhanced
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Critical Factors to Develop scCO2 Algae Oil Extraction Process
CO2
Vent to Algae
PBR
1080 kg/day
8 % Moisture
690 kg/day
Cracked Dried
Raw Algae
From Storage
PIC
PIT
PT
EX-101
Extractor
PT
EX-102
Extractor
DPT
E-104
Separator
Heat Exchanger
PT
EX-103
Extractor
PT
T-105
Separator
E-107
Refrigerated
Condenser
700 kg/day
Make Up
CO2
T-106
CO2
Accumulator
P-105
Crude
Algae Oil
Pump
Mass
Flow
Meter
Extracted
Algae Mass
810 kg/day
1 % Water
280 kg/day Total
200 kg/day Alg Oil
SC CO2
14,400 kg/day
E-108
CO2
Preheater
P-106
Extraction Pump
Pump
Suction
Pre-Chiller
Basis – 1 dry ton/ day algae
Make up – 700 kg/day, Available for algae pond – 700 kg/day
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By-product uses
• Aquaculture feeds
• Cells are still high in protein, carbohydrates,
micronutrients and phytochemicals
• Larval shrimp, fish, molluscs, crabs, worms
• Ornamental fishes
• Natural color in salmon
• Sources of beta-carotene, astaxanthin,
canthaxanthin, and other carotenoids