algal biodiesel stephanie dresen cbe 555 – fall 2014

Algal Biodiesel

Stephanie DresenCBE 555 – Fall 2014

Algal Biodiesel

• Background/Conventional Biofuels• Intro to Algal Biofuels• Genetic Modification of Algae Species• Mass Cultivation for Biodiesel Production• Algae Harvesting • Algae Lipid Extraction • Biorefining

Why does it matter?

• High Demand vs. Limited Supply • Energy Security and Independence • Environmental Concerns • Biofuels as a Possible Solution

1938 1981 1998 2005

Grinnell Glacier, Montana

Conventional Biofuel: Ethanol

• First Generation Ethanol (Corn Ethanol)• Derived from corn starch• 34% Green House Gas emission decrease• Over a century ago (1908), Henry Ford's

Model T was the first flexible-fuel vehicle, running on gas, ethanol or both

Other Potential Biofuels

• Cellulosic Ethanol• Biodiesel• Bio-hydrogen• Bio-hydrocarbons• Biobutanol• Methane• Jet Fuel• And on and on…

Available Biofuel Feedstocks (USA)

• Traditional Cereal Crops– corn, sorghum, wheat, rice

• Sugar-Producing Plants– sugarcane, sweet sorghum, sugar beet

• Dedicated Bioenergy Crops– switchgrass, miscanthus, reed canary grass, giant reed, poplar,

willow, eucalyptus• Oil (Lipid)-Producing Plants and Algae

– soybean, sunflower, rapeseed, peanut, palm oil tree, jatropha, algae• Forest

– Dedicated forest, low-quality forest biomass, thinnings

Algal Biofuels

“Some algal strains are capable of doubling their mass several times per day. In some cases, more than half of that mass consists of lipids or triacylglycerides—the same material found in vegetable oils. These bio-oils can be used to produce such advanced biofuels as biodiesel, green diesel, green gasoline, and green jet fuel.” – U.S. Department of Energy

Why Algae?

• Easy to grow: sunlight + water + CO2 (basically)• Useful byproducts: fertilizer & feedstock• Can be grown indoors with added nutrients• Production Output Potential– 100,000 gallons of algae oil per acre per year* – “it will take 140 billion gallons of algae biodiesel

to replace petroleum-based products each year”– much less land needed than current methods

Microalgal metabolic pathways that can be leveraged for biofuel production.

Radakovits R et al. Eukaryotic Cell 2010;9:486-501

Algal Biodiesel Production Process Flow

Algal Genetic Modification

• Genetic Engineering of Microalgae• Genetic Engineering of the Lipid Metabolism• Direct Biological Synthesis of Biofuels• Secretion of Triacylglycerol, Alkanes, Free Fatty Acids,

and Wax Esters• Genetic Modification of Carbohydrate Metabolism• Microalgal Hydrogen Production• Improved Growth Capacity Through Increased Stress

Tolerance or Increased Photosynthetic Efficiency

MASS CULTIVATION

Open Pond

Vertical Tank/Closed Loop

Closed Tank Bioreactor

Flat Plate-Type Photobioreactors

HARVESTING

Centrifugation

• Forces algae to bottom of tube and water can be decanted off the top

• Somewhat efficient, but…– Cells can be damaged while being pelleted– Unselective, all particles are collected – Expensive to run motors needed

• This method is being studied to address larger capacities, more efficient recovery at substantially lower speeds, and avoidance of pelleting

Microsreening/Filtration

• Filter screen coupled with a suction pump• Able to collect cells with very low density, good

for microalgae• Filter clogs quickly, leading to limited small

volumes at a time• New technologies to address this include using

a blade to rotate the algae to keep it suspended and a reverse-flow vacuum with pressure operating from above

Flocculation

• Addition of chemicals to force algae to clump• Processes to later remove chemicals are

currently costly and inefficient • Autoflocculation by interrupting the CO2

supply to an algal system is currently being researched

Common Algal Flocculants

• Alum – KAl(SO4)2·12H2O or AM(SO4)2·12H2O where A is a monovalent cation and and M is a trivalent metal ion

• Ferric Chloride – FeCl3 • Chitosan – deacylted chitin (crustacean shells)

Flotation

• Algae is made to float on surface and removed• Commonly used with flocculation• Froth Flotation– Adjust pH and bubble air through a column to

suspend algae in a froth above liquid– Currently, too expensive for commercial use

• Dissolved Air Flotation– Uses air compressor to create an algae/air mixture– Alum is then used to flocculate this mixture

LIPID EXTRACTION

Oil Press

Hexane Solvent Method

• Oils dissolve in the hexane and the remaining pulp is filtered out

• Hexane and oils are separated via distillation• Often used after Oil Press to remove

remaining oil from algae; able to remove 95%• Relatively inexpensive, however hexane is

flammable and chronic exposure has proven dangerous to humans

Supercritical Fluids Method

• Can extract up to 100% of oil from algae• CO2 is heated/pressurized to a supercritical

state, existing as both a liquid and a gas• This acts as a solvent dissolving the oil • When the mixture is moved to a lower

pressure, the oil separates out from CO2

• The additional equipment and work make this method very costly

BIOREFINING

Transesterification

Purification

• Biodiesel/Glycerol Separation: aided by centrifuge, remove biodiesel (top)

• Water-washing: Removes contaminants such as soap, residual methanol, free glycerin, and catalyst

• Drying: heated under vacuum to remove water

• Final Product – Biodiesel*

Algal Biodiesel

Pros• Abundant• Renewable• Carbon-Neutral• More energy/acre than

other biofuels• Scalable• Can be grown on land

unsuitable for agriculture• Wastewater and waste CO2

can be used as inputs

Cons• Open ponds are risky, and

other options are expensive• As for a transportation fuel,

there hasn’t been much (if any) testing using algal biodiesel in cars

• High up front capital and cost/gallon is high

• Considerable amount of water needed

The Future of Algae Biofuels

• In 2009, Exon planned to invest $600 million with a goal to develop algae fuels within 10 years

• In 2013, Exon announced it would be forced to restructure this algae research as at least another 18 years of research are needed

• In 2013, the Pentagon announced it would go ahead and spend $510 million to construct advanced biofuel plants

• Navy intends to buy $170 million gallons of renewable fuel/year to meet half of it’s fuel needs with renewable fuels by 2020

The Future of Algal Biofuels

• Like all biofuels, Algal Biodiesel has its pros and cons

• Like many biofuels, its production is currently too inefficient and expensive to compete with gasoline

• The future is uncertain, but as long as research continues, it is hopeful

References• Slide 1: Voegele, Erin. Biomass Magazine. (2014). [Picture]. DOE Opens Funding Opportunity for Algae Biofuel

Development. Retrieved from: http://biomassmagazine.com/articles/11009/doe-opens-funding-opportunity-for-algae-biofuel-development.

• Slide 3: Pan, X. (2014). Biorefining Overview (2) & Chemistry of Natural Products. [PowerPoint Slides]. Retrieved from: https://uwmad.courses.wisconsin.edu/d2l/le/content/2550594/Home.

• Slide 4: Pan, X. (2014). Overview of Fuel Ethanol. [PowerPoint Slides]. Retrieved from: https://uwmad.courses.wisconsin.edu/d2l/le/content/2550594/viewContent/15860708/View. Renewable Fuels Association. (2014). Ethanol Facts: Environment. Retrieved from: http://www.ethanolrfa.org/pages/ethanol-facts-environment.

Wenger’s Feed Mill Inc. (2014). [Corn Field Banner Picture]. Services: How can we help your business? Retrieved from: http://www.wengerfeeds.com/services.html.

• Slide 5: Shapley, Patricia. University of Illinois. (2012). [Picture]. Biodiesel. Retrieved from: http://butane.chem.uiuc.edu/pshapley/GenChem2/B11/3.html.

• Slide 6: Pan, X. (2014). Biomass Production. [Power Point Slides]. Retrieved from: https://uwmad.courses.wisconsin.edu/d2l/le/content/2550594/viewContent/15811251/View.

• Slide 7: U.S. Department of Energy. (n.d). Algal Biofuels. Biomass Program – Energy Efficiency and Renewable Energy. Retrieved from: http://www1.eere.energy.gov/bioenergy/pdfs/algalbiofuels.pdf.

• Slide 8: Newman, Stefani. (2014). How Algae Biodiesel Works. How Stuff Works. Retrieved from: http://science.howstuffworks.com/environmental/green-science/algae-biodiesel1.htm.

• Slide 9: Radakovits, Randor; et. al. American Society for Microbiology. (2010). [Figure 1 Picture]. Genetic Engineering of Algae for Enhanced Biofuel Production. Eukaryotic Cell, 9(4),486-501. Retrieved from: http://ec.asm.org/content/9/4/486.full.

References• Slide 10: Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Science. (n.d.).

[Process Flow Picture]. Retrieved from: http://www.qibebt.cas.cn/xwzx/tpxw/201206/t20120620_3602993.html.

• Slide 11: Radakovits, Randor; et. al. (2010). Genetic Engineering of Algae for Enhanced Biofuel Production. Eukaryotic Cell, 9(4), 486-501. Retrieved from: http://ec.asm.org/content/9/4/486.full.

• Slide 13: Hsu, Tiffany. Los Angeles Times. (2009). [Picture]. Interest in Algae’s Oil Prospects is Growing. Retrieved from: http://large.stanford.edu/publications/coal/references/hsu/. Newman, Stefani. (2014). How Algae Biodiesel Works. How Stuff Works. Retrieved from: http://science.howstuffworks.com/environmental/green-science/algae-biodiesel3.htm.

• Slide 14: Gramling, Carolyn. EARTH. (2009). [Vertical Photobioreactors Picture]. As Green As It Gets: Algae Biofuels. Retrieved from: http://www.earthmagazine.org/article/green-it-gets-algae-biofuels. Newman, Stefani. (2014). How Algae Biodiesel Works. How Stuff Works. Retrieved from: http://science.howstuffworks.com/environmental/green-science/algae-biodiesel3.htm.

• Slide 15: NanoVoltaics, Inc. (2009). Photo-Bioreactors. Retrieved from: http://www.nanovoltaics.com/content/photo-bioreactors.

• Slide 16: NanoVoltaics, Inc. (2009). Photo-Bioreactors. Retrieved from: http://www.nanovoltaics.com/content/photo-bioreactors.

• Slide 18: Oilgae. (n.d.). Algae Harvesting – Centrifugation. Retrieved from: http://www.oilgae.com/algae/har/cen/cen.html.

• Slide 19: Oilgae. (n.d.). Algae Harvesting – Filtration. Retrieved from: http://www.oilgae.com/algae/har/fil/fil.html.

References• Slide 20: Oilgae. (n.d.). Algae Harvesting – Flocculation. Retrieved from:

http://www.oilgae.com/algae/har/flc/flc.html. Anderton, William. Brigham Young University. (n.d.). [Flocculation Picture]. Harvesting Algae. Retrieved from: http://www.et.byu.edu/~wanderto/homealgaeproject/Harvesting%20Algae.html.

• Slide 21: Oilgae. (n.d.). Algae Harvesting – Flotation. Retrieved from: http://www.oilgae.com/algae/har/flo/flo.html.

• Slide 22: Oilgae. (n.d.). Algae Harvesting – Flotation. Retrieved from: http://www.oilgae.com/algae/har/flo/flo.html.

• Slide 24: Newman, Stefani. (2014). How Algae Biodiesel Works. How Stuff Works. Retrieved from: http://science.howstuffworks.com/environmental/green-science/algae-biodiesel2.htm. Anyang Gemco Energy Machinery Co.,Ltd. (n.d.). [Press Picture]. Oil Extraction Press. Retrieved from: http://www.oilpressmachine.com/6YL-80-oil-press.html.

• Slide 25: Oilgae. (n.d.). Extraction of Algal Oils by Chemical Methods. Retrieved from: http://www.oilgae.com/algae/oil/extract/che/che.html.

• Slide 26: Newman, Stefani. (2014). How Algae Biodiesel Works. How Stuff Works. Retrieved from: http://science.howstuffworks.com/environmental/green-science/algae-biodiesel2.htm.

• Slide 28: Pan, X. (2014). Biodiesel. [Power Point Slides]. Retrieved from: https://uwmad.courses.wisconsin.edu/d2l/le/content/2550594/viewContent/16019892/View?ou=2550594. Feltes, M.M.C. et. al. (2011). [Transesterfication Picture]. An Overview of Enzyme-Catalyzed Reactions and Alternative Feedstock for Biodiesel Production. In Alternative Fuel (Chapter 2). Retrieved from: http://www.intechopen.com/books/alternative-fuel/an-overview-of-enzyme-catalyzed-reactions-and-alternative-feedstock-for-biodiesel-production.

References• Slide 29: Pan, X. (2014). Biodiesel. [Power Point Slides]. Retrieved from:

https://uwmad.courses.wisconsin.edu/d2l/le/content/2550594/viewContent/16019892/View?ou=2550594.

• Slide 30: Siegel, RP. TriplePundit, LLC. (2012). Algae-Based Biofuels: Pros and Cons. Retrieved from: http://www.triplepundit.com/2012/04/algae-based-biofuel-pros-cons/.

• Slide 31: Harper, Evan. (2013). As Pentagon Invests in Green Fuel, Critics Focus on the Cost. The Los Angeles Times. Retrieved from: http://www.latimes.com/nation/la-na-green-military-20131118-story.html#page=2.

• Slide 32: Inhabitat, LLC. (2014). [PhotoBioReactor Picture]. PhotoBioReactor Sculpture by BIOS. Retrieved from: http://inhabitat.com/new-submission-30/attachment/12518/.

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