Techno‐economic Assessment of Mi l Bi P d i S Microalgae Biomass Production S ystems: Current Status & Future Opportunities Sudhagar Mani Assistant Professor Faculty of Engineering Assistant Professor , Faculty of Engineering University of Georgia, Athens Email: smani@engr.ug a.edu Bioenergy Engineering 2009 Conference October 11‐14 Bellevue WA October 11 14, Bellevue, WA
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Techno economic Assessment of Mi lMicroalgae Biomass … Cost... · Micro‐algae Production Cost 32000 30000 35000) Raceway Pond 20000 17000 25000 ... Paddle wheel speed 30 cm/sec.
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Techno‐economic Assessment of Mi l Bi P d i SMicroalgae Biomass Production Systems:
Current Status & Future Opportunities
Sudhagar ManiAssistant Professor Faculty of EngineeringAssistant Professor, Faculty of Engineering
H – Tubular systemHelical Tubular systemHelical Tubular system
V – Column system
Alpha shaped system Flat plate system
Open Pond SystemOpen Pond System
Race way Pond – Earthrise Farms Race way Tanks
Open vs. Closed Photo‐bioreactors
Features Open System (Raceway pond)
Closed system (PBR)( y p )
Area‐to‐volume ratio Large (4‐10 times) Small
Growth efficiency Low (0 01‐0 2 g L‐1d‐1) High(0 1‐7 g L‐1 d‐1)Growth efficiency Low (0.01 0.2 g L d ) High(0.1 7 g L d )
Harvesting efficiency Low High
Light util. efficiency Poor‐fair Fair‐excellent
Gas (mass) transfer Poor High( ) g
Water loss Possible Restricted
Capital Investment Small (10‐20 times) High
Sources: Eriksen, 2008; Carvalho et al., 2006; Ugwu et al., 2008
Micro‐algae Production Cost32000
30000
35000
)
Raceway Pond
1700020000
25000
Cost ($
/t)
7320
17000
800010000
15000
oduction
470266011601000 921 600 430 398 272
0
5000
Alga Pr
ObjectivesSystematic techno‐economic evaluation of algae
cultivation & harvesting systemsC d t iti it l i th i d l tConduct sensitivity analysis on the economic model to
improve and progress towards advanced systems
So, what's New?
Annual target based dedicated microalgae productionAnnual‐target based dedicated microalgae production facility – Capital cost vs Operating cost
Individual cost estimation each unit operations
Production cost vs Influencing factorsProduction cost vs Influencing factors
System Boundary – Economic Analysis
GROWTH Primary Harvest
Secondary harvest
Algae 20% solid
RacewayMicro‐strainer
V B l FilCentrifugeRaceway
PondsVacuum Belt Filter
DAFBelt Press Algae
with 20%
Photo‐BioReactors(PBR)
Centrifuge
Belt Press
20% solid content ( )
Basis of Comparison: 1000 dry tons/year for 300 daysBasis of Comparison: 1000 dry tons/year for 300 days operational plant
Methodology
Spreadsheet based model analyzing different options for each stage
Order of magnitude estimation ( 20 to +30 accuracy) fromOrder of magnitude estimation (‐20 to +30 accuracy) ‐ from already published data (Peters, Timmerhaus, West 2003)
Cost of A’s capacity = Cost of B’s capacity * (A’s capacity/B’s capacity)^scale factor
Cost updated to the present value using Chemical Engineering Cost IndexCost Index
Capital cost – Equipment cost, installation, piping, electric lines, land cost, taxes, interests & insurances
Power, Labor, Equipment maintenance & Material requirements accounted for operating cost
d i ( ) d i $Production cost (Cap. + Op. costs) are reported in 2009 US $
Photo‐BioReactor (PBR)
GROWTH No First Harvest Second Harvest
Capital cost comparison for•Controlled & high Growth
•Maximizing photosynthetic
Capital cost comparison forflat plate, bag and tubularsystemefficiency
•Contamination controlOperating cost for tubularsystem only Tubular PB
Raceway pond Operation : Steady‐state continuous mode, 25% volRaceway pond Operation : Steady state continuous mode, 25% volDaily Harvest Flow: 4658 cu. m @ 194 cu.m/hEach harvest unit operates 24 X 7 for 300 days/year.
DISSOLVED AIR FLOATATION CENTRIFUGE
45 cu.m/h
6% SFLOATATION
MICRO
CENTRIFUGE194 cu.m/h
194 cu.m/h 20% S
6% S
RACEWAY POND
STORAGE POND
MICROSTRAINER
VACUUM BELTBELT PRESS0.4%
solids
4% S
VACUUM BELT FILTER
solids
6% S 20% S
Dissolved Air Floatation (DAF) System
Micro‐Strainer
Belt Press/Filter System
Open Pond Algae Cost Comparisons
operating cost/tonne Annual Capital cost/tonne Total Cost/tonne
1,120 1,221
1,067 1,054 1,210
1,058 1230
$/tonn
e
Pond + microstrainer
Pond + belt filter + Cfg
Pond + DAF + Cfg (3)
Pond + microstrainer
Pond + belt filter + belt
Pond + DAF + belt press(6)
Photo bioreactor +
+ Cfg (1) (2) +belt press (4)
press (5) Centrifuge
Scenarios
Algae Drying Energy
Source: NREL
HDD System
Future Challenges & Opportunities
• Genetic Engineering approach on algae species to improve algaeproductivity and species that can withstand stress conditions• Better understanding on Lipid and carbohydrate biosynthesispathways•Identification and isolation of new algae species that can capable ofIdentification and isolation of new algae species that can capable ofgrow faster and accumulate lipids• Improved photo‐bioreactor designs for large scale applicationsD l f h i id h i• Development of new harvesting systems or even avoid harvesting
• Attached algae growth system show some promises as they cancompletely avoid both primary and secondary harvesting options• Use of low cost nutrient and CO2 sources can reduce algaeproduction cost, but will not solve the entire problem• Combination of PBR & Raceway pond systems are becomingCombination of PBR & Raceway pond systems are becomingattractive for large scale algal production system
Conclusions1. Microalgae biomass can play a significant role in the Renewableg p y g
Energy Portfolio2. Photo‐bioreactors are also attractive to grow algae ($1230/t) under
stress conditions for lipid accumulation and at higher productivitystress conditions for lipid accumulation and at higher productivity(3g/l). However more research is required on designing low cost andefficient photo‐bioreactor systems.
d i f i l i d ($ / ) l k3. Production of microalgae using raceway ponds ($1050/t) looksattractive. However, significant research progress has to be made toadvance this technology to become commercially and economicallygy y yviable
4. Currently, DAF+Belt press or DAF+Centrifuge systems are attractiveeconomically for open pond systemseconomically for open pond systems
5. Newer harvesting technologies are evolving, however they need tosatisfy current economic constraints.
6 I i l d i i h h G i E i i6. Increasing algae productivity through Genetic Engineeringapproaches and improving lipid biosynthesis would further reducethe cost of algae significantly.
Acknowledgement
Research TeamMr. Thiru Viswanathan – Graduate StudentDr S Chinnasamy Research ScientistDr. S. Chinnasamy, Research ScientistDr. KC Das, Associate Professor
Financial Support:Financial Support:Department of Energy (DOE)TIP3 Program – State of Georgia
References
Max S. Peters, Klaus D. Timmerhaus, Ronald. E. West, Plant Design Economics forCh i l E i Fifth Editi M G Hill NY 2003Chemical Engineers‐ Fifth Edition, McGraw‐Hill , NY, 2003.
Perry et al., Chemical Engineering Handbook Fifth Edition, McGraw‐Hill, NY, 2007.
Benneman and Oswald, System and Economic analysis of Microalgae ponds forconversion of carbon dioxide to biomass 1996; PETC Final Report.