Chandra Theegala

Report
Dr. Chandra Theegala
Department of Biological and
Agricultural Engineering
Louisiana State University
ARE WE THERE YET ON ALGAL
BIOFUELS: WHAT REMAINS TO BE
DONE?
Chandra Theegala*, Adam Dassey, Beatrice Terigar, Javed
Iqbal, Ronald Malone
*Chandra S. Theegala, Ph.D.
Associate Professor
Biological and Agricultural Engineering
LSU AgCenter & LSU
Baton Rouge, LA
Overview of Presentation
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Biodiesel facts and need for biodiesel lipids
Potential of algae as a biodiesel feedstock
Primary challenges and my research solutions
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Cost-effective cell harvesting & dewatering*
High infrastructure cost*
Need for intensification of aerial productivity*
Benign and cost-effective lipid extraction #
Contaminant mitigation and species dominance (PhD work)
Questions & Answers (slide number will help)
* Critical today
# Excluded due to time limitations
3
Biodiesel Facts and Need for Lipids
 US diesel needs: ~ 60 billion gal/year
 Total
US transportation fuel needs ~ 200 billion gal/year
 Biodiesel production (2011-12) ~ 1.1 billion gallons/year
 Biodiesel production limited by feedstock availability
 Biodiesel – Advanced/non-starch fuel. RFS2: 21 billion gallons
 Bottomline: Need new and non-food/feed sources of oil
 Microalgae has potential to produce 2,000 - 3,000 (or more)
gallons/acre/year (compared to ~70-80 gal/acre/year from soybean)
 Several limitations exist for microalgal biofuels
Reality Snapshot/In a Nutshell:
US Navy Contract to Solazyme: ~$425/gal
(20,000 gal, heterotrophic direction)
4
Biodiesel Economics
~ Approx. Production Figures
Description
 Oil (1 gallon, 7.5 lb)
 Methanol (0.11 gal x 1.5)
 Catalysts + Chemicals
 Natural gas + Electricity
 Labor + Maintenance
 Interest/Depreciation
Final Cost:
Unit Cost
$0.53/lb
$1.45/gal
Cost/gallon
$3.97
$0.24
$0.10
$10/mmbtu; $0.10/Kwh $0.03
$0.10
$0.15
-----------------------$4.59
= Oil cost + $0.60
Govt. Incentives/Subsidy (-)
Distributor/retailer profit (+),
Transportation (+)
5
Oil Productivities of Various Crops
Crop
Oil Yield
[gal / acre]
Total Cropping Area Required
for Meeting 100%
Transportation Fuels Needs
Corn
Soybean
18
48
1,692%
652%
Canola
Jatropha
Coconut
127
202
288
244%
144%
108%
Oil palm
Microalgae (Estimate)
30% lipids
70% lipids
636
48%
6,275
14,633
5%
2.2%
Source: Modified from Chisti, 2007.
6
Sustainability – Practicality??
Crop
Oil Yield
[gal / acre]
Acreage Needed for Average
Family (~1200 gallon per year)
Soybean
Canola
Jatropha
48
127
202
25 acres
9.5 acres
6 acres
Coconut
Oil palm
Microalgae
Chisti’s Estimate
30% lipids
70% lipids
My Estimate
288
636
4.2 acres
2 acres
6,275
14,633
2,000
0.2 acres
0.08 acres
0.6 acres
7
Microalgal Facts
 Several species have up to 40-60 % lipids contents.
 Several species can grow at extremely fast growth rates.
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(think of 1 foot plant going 7 to 10 feet by end of the day)
High biomass productivity & high lipids contents are mutually
exclusive
High lipid strains are slow growing and highly susceptible to
contamination
Several thousands of recognized species of microalgae.
But less than a handful can be mass produced outdoors (Weeds
& predation).
Production from microalgae is not straight forward (several
challenges exist).
Low solar energy conversion efficiencies (~2-3%). So surface
area and open ponds are important (PBRs????, for biofuels? ) 8
Primary Limitations for Microalgal Biofuels
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High harvesting costs (Think – Removing color in water!)
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High infrastructure costs
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Need for intensification (70 gal/acre works, but 2000 does not?)
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Need for benign and cost-effective lipid extraction #
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Species dominance & contaminant control in open cultures (PhD)
# Not covered due to time limitations
9
Cost Effective Harvesting & Dewatering
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Very challenging task. Think – Removing color in water!
100 mg-dry/L (0.01%) to 20% solids. 2000 times for <$2-3/g-oil
Need 50-100 harvest cycles per year. Why?
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Low culture density (100-150 mg/L) is key for fast growth
Specific growth rates plummet with increasing density
Each cycle - Huge volume to process (660,000 gal). Yield ~22 gal
(assuming 150 mg/L density and 20% lipids, 2 ft. depth).
This is a money loser!
Economics will not improve with more harvest cycles
(1 cycle loss will project to bigger loss on 100 cycles)
Centrifuges – effective but costly
 Microscopic & unicelluar~5 microns
 Marginal density differences (SP ~1)
 2000-3000+ g forces
 > $25/gal oil
10
LSU BAE - Microalgal Research Team (Spring 2012)
Covering all bases!!
Adam, PhD*Harvesting
Mostafa
Jacob
Beatrice, PhD*
Lipid
Intensification/
Light Optimization
PhD – Species Dominance/
Contaminant Control
Javed, PhD –
Lipid Extraction
Nick, MS*- Species
Screening
11
Dissolved Air Flotation Prototype
12
Electro-flocculation
•100 times concentration from 0.01% to 1%
•But not a complete solution
•Cost of aluminum (coagulant) released – high
•Cheaper metal electrodes - promising
13
Proprietary 3-stage Harvesting System
(Disclosure and Possible Patent)
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Cheapest way from 0.01% to 20%
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Operating at ultra-lean modes
Major synergistic benefits
Target price < $2-3/gallon (Final runs this week ! ?)
14
High Infrastructure Cost
 Pond
and raceway construction costs are higher
 Ocean based culture systems to lower construction costs
 Indirect approach to address high infrastructure costs
Intensify lipid yield from 2,000 to 8,000–15,000/gal/acre/year
 Will this effectively lower the burden of high infrastructure costs?
Source: Sapphire Energy
Source: Algenol
Source: Popular Mechanics.com
15
Lipid Intensification, Light Optimization, Improved
Pond Designs
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Full sunlight is PAR ~ 2,000 µmol/m2/s. Is this really needed?
Are the current raceways and ponds ideal for high aerial
productivity?
DOE’s FOA 0000811, Target for 2018: 2,500 gal/acre/year
We have a developed novel techniques that shows major promise
Already proven at 2 levels (indoor 2 L bench-scale, outdoor 25 L
prototype scale)
Awaiting final field-scale test results this summer.
Anticipating lipid yields of 8,000-15,000 gal/acre/year
Operational costs? If proven successful, this will be a major
breakthrough for algal biofuels.
The Contamination Problem & Species Dominance
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Facts
Several thousands of microalgal species
But only a handful can be mass cultivated.
High lipid and weaker strains – gets replaced in outdoor
ponds
Spirulina – high alkalinity
Contamination Problem
1) Replacement by faster growing algal species
2) Predation by higher organisms.
Ideal Plug Flow
CONTAMINANT SLUG (Non-multiplying)
TIME
CONTINUOUS
% WASHOUT IN ONE HRT = 100 %
18
Series of CSTRS Mimics Plug Flow
Contaminant
10 cells
Algae
Contaminant may grow
But never displaces the main species
Higher Density
1000 cells
19
108 Cells
Hydraulically Integrated Serial Turbidostat Algal
Reactor (HISTAR) : My PhD work.
Co-Advisors: Dr. Ronald Malone & Dr. Kelly Rusch
media
Inoculum
media
water
Turbidostat
Series of CFSTRs
 Pure inoculum
 Outdoor- amplifier
 Biomass increases with CSTR
 Open to atmosphere
20
Computer Automated 3,000 gallon - HISTAR
System
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Contaminant Washout Demonstrated
 Purposefully added
300 million rotifers
 System did not
collapse
 Algal species and
predators got flushed
out
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Are We There Yet?
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Microalgae has lots of potential. 30x soybean yield (200x?) - Yes
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Cost-effective harvesting – No (not yet)
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Reduce frequency of harvesting from 50-100 harvest cycles/year
Get more oils per each harvest
Economics should be favorable at 1 harvest cycle
Bottomline: Lower harvesting/dewatering cost to < $1-2/gallon-oil
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Intensification of lipids to 5,000 gal/acre/year – No (not yet)
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Species and contamination control - Yes
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Methods exist for species and contaminant control
DOE-ASP report (20 years research) - Grow native species
Control is preferable for maximizing yield & lowering harvest frequency
Are We There Yet?
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Lipid Extraction - Yes
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Bio-refinery Model – Not There, But Can Happen
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Effective methods do exist
But need more benign techniques (non-hexane based, biodiesel solvent)
Other value added products – critical for industry (say proteins,
nutraceuticals, animal feeds, etc.
Genetic/Novel Research – Futuristic (this is all we need!)
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Can drastically change the bioenergy scenario
High lipids in proven and strainable Spirulina! Will be a winner!!
No more bioenergy solutions needed
Questions?
Chandra Theegala
Associate Professor
Bio & Ag Engineering
LSU AgCenter/LSU
Email: [email protected]
Phone: (225) 578 1060
Dr. Chandra Theegala
Department of Biological and
Agricultural Engineering
Louisiana State University

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