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!

QUESTIONS?

rex@process.co.zawww.process.co.za