Download Chandra Theegala

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
Canola
18
48
127
1,692%
652%
244%
Jatropha
Coconut
Oil palm
Microalgae (Estimate)
30% lipids
70% lipids
202
288
636
144%
108%
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
Coconut
48
127
202
288
25 acres
9.5 acres
6 acres
4.2 acres
Oil palm
Microalgae
Chisti’s Estimate
30% lipids
70% lipids
My Estimate
636
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
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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 ! ?)
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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
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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
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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