ALGAE TO ETHANOL: Using algae fermentation to produce ethanol 4 th AFRICAN BIOFUEL CONFERENCE March...
54
ALGAE TO ETHANOL: Using algae fermentation to produce ethanol 4 th AFRICAN BIOFUEL CONFERENCE March 2009
-
Upload
isiah-whiston -
Category
Documents
-
view
218 -
download
0
Transcript of ALGAE TO ETHANOL: Using algae fermentation to produce ethanol 4 th AFRICAN BIOFUEL CONFERENCE March...
ALGAE TO ETHANOL: Using algae fermentation to
produce ethanol
4th AFRICAN BIOFUEL CONFERENCE
March 2009
Algae!
Why Algae?
• Fast growers relative to other plants and animals– can double their weight every day
• High carbohydrate/low lignin content• Gallons of oil per acre per year
– corn 18
– soybeans 48
– sunflower 102
– rapeseed 127
– oil palm 635
– micro algae 5 000 - 15 000
Process Selection Objectives…
• Must be simple• The process itself must be “bullet proof”• Must have low maintenance• A labourer must be able to look after algae production• A semi-skilled labourer must be able to run conversion• Must have low operating costs
– little or no nutrient cost
– little or no energy cost
Why ethanol and not oil for biodiesel?
Why Algae to Ethanol…
• Wild algae– have to be fast growers to survive in nature
– generally contain <10% oil (lipid)
– generally contain high carbohydrate >50%
– can be grown in open raceways without fear of contamination
• Equipment– raceways are low cost installations ($75 000/ha)
– raceways consume very little power (10 kW/ha)
– starch to ethanol conversion plant is relatively expensive and energy intensive (distillation)
Why Algae to Ethanol…
• High oil producing algae – are slower growers than wild algae – double every 2-3 days
– can be selected for maximum oil content – 50% not unusual
– need to be grown in protected environment – typically PBR’s
– most algae oil can be used for biodiesel production
• Photobioreactors (PBR’s)– allow tight control of growing environment
– optimise light usage
– are capital intensive
– are generally power intensive (300 kW/ha?)
General Processing Steps
Algae to Ethanol
Processing Steps
Algae
oxygensunlight
CO2
Processing Steps
Algae
Concentration
dlute slurry
liquid
oxygensunlight
CO2
Processing Steps
Algae
Concentration
dlute slurry
liquid
Hydrolysis
acidconcentrated slurry
heat
oxygensunlight
CO2
Processing Steps
Algae
Concentration
liquid
Hydrolysis
concentrated slurry
Fermentation
alkali
heat cooling
dlute slurry
acid
oxygensunlight
CO2
yeast
Processing Steps
Algae
Concentration
liquid
Hydrolysis
concentrated slurry
Fermentation
alkali
heat cooling
Distillation
“beer”
ethanol
dlute slurry
acid
oxygensunlight
CO2
yeast
Processing Steps
Algae
Concentration
liquid
Hydrolysis
concentrated slurry
Fermentation
alkali
heat cooling
Distillation
“beer”
Digestion
stillageethanol
dlute slurry
acid
oxygensunlight
CO2
yeast
Processing Steps
Algae
Concentration
liquid
Hydrolysis
concentrated slurry
Fermentation
alkali
heat cooling
Distillation
“beer”
Digestion
stillage
liquid digestate
ethanol
solid digestate
dlute slurry
acid
oxygensunlight
CO2
biogas
yeast
Processing Steps
Algae
Concentration
liquid
Hydrolysis
concentrated slurry
Fermentation
alkali
heat cooling
Distillation
“beer”
Digestion
stillage
liquid digestate
ethanol
solid digestate
dlute slurry
acid
oxygensunlight
CO2
CO2
biogas
yeast
Processing Steps
Algae
Concentration
liquid
Hydrolysis
concentrated slurry
Fermentation
alkali
heat cooling
Distillation
“beer”
Digestion
stillage
liquid digestate
ethanol
solid digestate
biogas
dlute slurry
acid
oxygensunlight
CO2
CO2
CO2
CO2
yeast
Processing Steps
Algae
Concentration
liquid
Hydrolysis
concentrated slurry
Fermentation
alkali
heat cooling
Distillation
“beer”
Digestion
stillage
liquid digestate
ethanol
solid digestate
biogas
dlute slurry
acid
oxygensunlight
CO2
CO2
CO2
CO2
CHPCO2 ~
yeast
Pilot Plant
Pilot Plant
• Components– 20m2 raceway with 0.55 kW paddle drive
– solar panels to supply heat to the digester
Pilot Plant
PilotPlant
Pilot Plant
Pilot Plant
• Components– 20m2 raceway with 0.55 kW paddle drive
– solar panels to supply heat to the digester
– digester
Pilot Plant
Pilot Plant
• Components– 20m2 raceway with 0.55 kW paddle drive
– solar panels to supply heat to the digester
– digester
– “compost tea” maker
Pilot Plant
Pilot Plant
• Components– 20m2 raceway with 0.55 kW paddle drive
– solar panels to supply heat to the digester
– digester
– “compost tea” maker
– DAF container to make “white water”
Pilot Plant
Pilot Plant
Pilot Plant
Pilot Plant
• Components– 20m2 raceway with 0.55 kW paddle drive
– solar panels to supply heat to the digester
– digester
– “compost tea” maker
– DAF container to make “white water”
– stainless steel pressure cooker
Pilot Plant
Pilot Plant
• Components– 20m2 raceway with 0.55 kW paddle drive
– solar panels to supply heat to the digester
– digester
– “compost tea” maker
– DAF container to make “white water”
– stainless steel pressure cooker
– plastic fermenter
Pilot Plant
Pilot Plant
• Components– 20m2 raceway with 0.55 kW paddle drive
– solar panels to supply heat to the digester
– digester
– “compost tea” maker
– DAF container to make “white water”
– stainless steel pressure cooker
– plastic fermenter
– electrically operated stainless steel batch still
Pilot Plant
Pilot Plant
• Components– 20m2 raceway with 0.55 kW paddle drive
– solar panels to supply heat to the digester
– digester
– “compost tea” maker
– DAF container to make “white water”
– stainless steel pressure cooker
– plastic fermenter
– electrically operated stainless steel batch still
– various tanks, pumps, drums and buckets
Pilot Plant
Pilot Plant Results
• Main Production Results
– algae density 4 gram/litre
– growth 140 g/m2/day
– oil recovery negligible
– ethanol production 50 - 70 ml ethanol/m2/day
Moving Toward Commercialisation
Production Plant Projection
Item Units 500 l/day 5000 l/day
Pond area ha 1.0
Installed power kW 30
Capital cost $ 600k
Variable cost $/litre 0.05
Fixed costs $/year 17.5k
Selling price $/litre 0.50
Sales $ 85k
Gross profit $ 59k
Production Plant Projection
Item Units 500 l/day 5000 l/day
Pond area ha 1.0 10
Installed power kW 30 150
Capital cost $ 600k 2.75m
Variable cost $/litre 0.05 0.1
Fixed costs $/year 17.5k 35k
Selling price $/litre 0.50 0.50
Sales $ 85k 850k
Gross profit $ 59k 645k
Commercial Production
• Physical requirements– relatively level site
Commercial Size Site
Commercial Size Site
Commercial Size Site
Commercial Production
• Physical requirements– relatively level site
– water
– power to drive paddles
• Potential deployment for “emerging farmers”– can be deployed to tribal areas
– relatively low cost for ponds ~ R75/m2
– centralized conversion plant: • can use a tanker for moving algae nutrient and concentrate to and
from algae ponds to centralized plant• better economy of scale for larger plant• better process and inventory control
Challenges to Commercialization
• Oil price stability• High capital cost• Limited markets at small volumes• Theft of product• Challenges to tribal area deployment
– Power for paddles: solar?
– Theft and vandalism – cables, tanks and pumps are vulnerable
Summary
• Production of algae to produce ethanol is economically viable• Wild algae production does not require a lot of attention• Can be rolled out for emerging farmers• Conversion plant operation requires semi-skilled expertise
Growing algae in the snow!
Growing algae in the snow!
Growing algae in the snow!
