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CO2 to Bioplastics: Beneficial Re-use of Carbon Emissions from
Coal-Fired Power Plants Using Microalgae
Mark CrockerUniversity of [email protected]
1
Project Overview(DE-FE0029632)
Funding: DOE: $999,742Cost share: $258,720Total project: $1,258,462
Performance dates:6/1/2017 – 5/31/2020
Project Participants:- University of Kentucky- Colorado State U. - Algix LLC- Duke Energy
Project Objectives:
• A dual PBR/pond cultivation system will be evaluated with respect to capital and operational costs, productivity, and culture health, and compared to pond-only cultivation systems
• A high-value biomass utilization strategy will be developed to simultaneously produce a lipid feedstock for the production of fuels, a carbohydrate feedstock for conversion to chemicals and/or bio-ethanol, and a protein-rich meal for the production of algal-based bioplastics
• Techno-economic analyses will be performed to calculate the cost of CO2 capture and recycle using this approach, and a life cycle assessment will evaluate the potential for reducing greenhouse gas emissions.
2
3
Background:
Highlights from DE-FE0026396:A Microalgae-based Platform for the Beneficial
Reuse of CO2 Emissions from Power Plants
Media
Drying
Dewatering
Coal Power Plant
Biomass Fractionation
Lipids,Protein +
carbohydrate
CO2 Lean Gas
Recovered Nutrients (N,P,K)
Recovered Media
Recovered Water
Algae Cultivation
Technology Background: Process Schematic
Liquid fuels,Bioplastics
Nutrients(N, P, K)
Scrubbed flue gas,10 psig
12 – 40 ⁰C,pH 6 - 8
4
East Bend Station Demonstration Facility
Capacity: 650 megawattsLocation: Boone County, KYCommercial Date: 1981 650 MW Scrubbed Unit (SCR, FGD, ESP)
MAIN GOALS• Define kinetics of process
– Monitor dissolved CO2 and O2 to determine photosynthetic rate
– Help size large system and next generation design• Gain understanding of real capital and operating costs
– Minimize energy consumption• Measure biomass composition to track heavy metals
and other flue gas constituents5
CO2 % NOxppm
SO2 ppm
Average 8.9 53.4 28.0
Minimum 7.2 14.5 6.5
Max. 9.6 97.2 84.3
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“Cyclic Flow” Photobioreactor (1100 L) Installed at East Bend(2nd Generation PBR)
Summer 2014 May 2015
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System Biology: Effect of Flue Gas Constituents on Algae Growth
Experimental Design:• Three gas treatments: Air/Control
(400 ppm CO2), 9% CO2, and simulated flue gas (9% CO2, 55 ppm NO, 25 ppm SO2).
• Four replicate cultures for each treatment
• Flow rates were maintained between 2.3-2.5 ml/min for each replicate for all treatments.
• Cultures were acclimated to the gases for two batch cycles before starting experiment (transferred before reaching stationary phase)
Results: • There was no statistical difference in
productivity between simulated flue gas and CO2-grown cultures.
Treatment
Air CO2 Flue Gas
Productivity (g L-1 Day-1) 0.018 0.268 0.266
Specific growth (µ) 0.22 0.389 0.307
Dry weight of S. acutus during log phase growth when maintained in urea media. (Mean ± SD)
Productivity and specific growth rates during log phase growth when maintained in urea media
Air
9% CO2Sim. flue gas
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System Biology: Bicarbonate Addition as a Means of Sustaining Algae Cultures
Dry weight of Scenedesmus acutus. Arrow indicates where flue gas was shut off. (Mean ± SD)
Fv/Fm (photosynthetic efficiency) for each treatment after flue gas was shut off. (Mean ±SD). Fv/Fm for the air treatment was significantly lower than for the other treatments
NaHCO3 addition (5 mM) shown to be effective for preserving culture health in absence of flue gas
Sim. flue gas shut off
9
System Biology: Analysis of East Bend PBR Algae Culture
% C
ompo
sitio
n
6.14
6.
16
6.17
6.
22
6.24
6.
27
6.2a
6.
2b
7.06
7.
11
7.18
7.
19
7.21
a 7.
21b
7.25
a 7.
25b
7.27
a 7.
27b
7.29
a 7.
29b
8.01
8.
04a
8.04
b 8.
08a
8.08
b 8.
09
8.11
8.
15
817
100
75
Sp Chlorococcum sp.
Desmodesmus pannonicus
Diplosphaera sp.
50 Graesiella vacuolata
Parachlorella beijerinckii
Scenedesmaceae
Scenedesmus
Scenedesmus littoralis
25
0
Date
• Community sequencing analysis of the PBR in summer 2016 showed contamination by Chlorococcum sp. in mid to late July, followed by a contamination event that was dominated by Graesiella vacuolataand Parachlorella beijerinckii
• Towards the end of the culturing campaign at East Bend, excessive temperatures caused the Scenedesmus culture to crash. However, this provided an opportunity for an invasive species of algae to flourish, identified as Coelastrella saipanesis.
• Although a green alga, when stressed the cells turn red due to the production of a potentially valuable pigment (most likely β-carotene).
East Bend Algae ProductivitySummer 2015
10
Algae productivity = 0.165 ± 0.057 g/(L.day), equivalent to ca. 35 g/(m2.day)
0
2
4
6
8
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12
14
16
18
0.00
0.05
0.10
0.15
0.20
0.255-
May
8-M
ay11
-May
14-M
ay17
-May
20-M
ay23
-May
26-M
ay29
-May
1-Ju
n4-
Jun
7-Ju
n10
-Jun
13-J
un16
-Jun
19-J
un22
-Jun
25-J
un28
-Jun
1-Ju
l4-
Jul
7-Ju
l10
-Jul
13-J
ul16
-Jul
19-J
ul22
-Jul
25-J
ul28
-Jul
31-J
ul3-
Aug
6-Au
g9-
Aug
12-A
ug15
-Aug
18-A
ug
Tota
l PAR
, µm
ol/m
2/da
y x E
9
Cultu
re P
rodu
ctiv
ity, g
/lite
r/da
yFlue Gas Bottled CO2 PAR
Plant outage
Plant outage
M.H. Wilson, D.T. Mohler, J.G. Groppo, T. Grubbs, S. Kesner, E.M. Frazar, A. Shea, C. Crofcheck, M. Crocker, Appl. Petrochem. Res., 2016, 6, 279-293.
11
Av. CO2 capture efficiency during daylight hours = 44%
0
20
40
60
80
100
120
0
2
4
6
8
10
12
14
16
18
20
7/7/2016 7/7/2016 7/8/2016 7/8/2016 7/9/2016 7/9/2016 7/10/2016 7/10/2016 7/11/2016 7/11/2016
ppm
NO
x an
d SO
x
% C
O2
and
O2
CO2 out
O2 out
NOx
SOx
O2 production correlates with CO2 consumption Complete SOx removal from flue gas; ca. 50% NOx removal
Typical PBR Outlet Gas Composition
12
y = 0.9243x - 0.0041R² = 0.6829
-0.20
-0.10
0.00
0.10
0.20
0.30
0.40
0.50
-0.10 0.00 0.10 0.20 0.30 0.40 0.50
∆n C
O2
(mol
s) co
nsum
ed
∆n O2 (mols) produced
• Data plot confirms close to linear relationship between CO2 uptake and O2production, confirming that the latter is a good indicator of CO2 consumption
• Observed O2/CO2 ratio of slightly greater than 1 (1.08 in this case) is consistent with literature
CO2 consumed vs. O2produced (5 s data). Graph indicates a direct linear correlation between CO2 consumed and O2produced with a slope of 0.92 and intercept of 0.0041. The quality of the R2 value was impaired by the inclusion of data corresponding to an unhealthy culture on 7/23/16.
CO2 Consumption vs. O2 Production
13
• Optimal O2 production is more temperature dependent than previously thought• Highest O2 production trend occurs at process temperatures and PAR values of 35-38.5 oC and
1200-2000 µmol/(m2s), respectively
Engineering Analysis: East Bend Station Data (1200 L PBR)O2 Production vs. Process Temperature, PAR & pH
Carbon Mass Balance (East Bend PBR, summer 2016)
14
0
50
100
150
200
250
300
350
400
7/18-7/21 7/21-7/25 7/25-7/27
mas
s C (g
)
Target Dry Mass C (g) Dry Mass C (g)
Error bars represent the st. dev. for triplicate dry mass measurements (orange columns) and the error associated with the CO2 gas analyzer (blue columns)
• Overall, reasonable agreement is obtained between measured carbon accumulation (“dry mass”) and calculated carbon uptake in PBR (“target dry mass”)
• The discrepancy in numbers for the 7/21-7/25 growth period can be attributed to significant biofilm formation within the reactor, as observed during that time.
𝑚𝑚𝑐𝑐𝑑𝑑𝑑𝑑𝑑𝑑𝑚𝑚𝑚𝑚𝑚𝑚𝑚𝑚 = (𝜌𝜌2 − 𝜌𝜌1)𝑉𝑉𝑅𝑅𝑤𝑤𝑐𝑐𝑚𝑚𝐶𝐶𝑡𝑡𝑡𝑡𝑡𝑡𝑡𝑡𝑡𝑡𝑡𝑡 = 𝑚𝑚𝐶𝐶𝑡𝑡𝑡𝑡𝑔𝑔 + 𝑚𝑚𝐶𝐶𝑢𝑢𝑑𝑑𝑢𝑢𝑚𝑚 𝑐𝑐𝑐𝑐𝑐𝑐𝑚𝑚𝑢𝑢𝑚𝑚𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐 − 𝑚𝑚𝐶𝐶𝑚𝑚𝑐𝑐𝑠𝑠𝑐𝑐
Analysis of Waste Heat Integration with PBR
15
y = -0.00024x + 0.00003R² = 0.25402
-0.01
-0.005
0
0.005
0.01
-5 -4 -3 -2 -1 0 1 2 3 4 5
𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠 =𝑈𝑈𝑈𝑈
𝑚𝑚𝑅𝑅𝐶𝐶𝑠𝑠𝑅𝑅𝑈𝑈𝐷𝐷𝑡𝑡𝑡𝑡𝑡𝑡 = 23.8
𝑊𝑊𝑚𝑚2𝐾𝐾
Experimental Determination of U (Overall Heat Transfer Coefficient) using Data from 2015 Growing Season
0
10
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30
40
50
60
70
0 2 4 6 8 10 12Ove
rall
Redu
ctio
n in
CO
2Ca
ptur
e
(%)
Tamb (°C)
Reduction in Overall CO2 Capture vs. Ambient Temperature
Assumptions: 30% CO2 capture from a 1 MW coal-fired power plant
Heat source = boiler water (910,000 L/min, T = 32-45 ⁰C)
Increased CO2 emissions arise from pumping boiler water to PBR heat exchanger and increased cycling of PBR culture through heat exchanger
16
• Extent of solids capture is limited if only cationic flocculant is used (regardless of flocculant mol. wt.)
• Anionic flocculants by themselves are not effective
• However, 95% solids capture is possible by addition of 1 ppm of anionic flocculant to algae pre-flocculated with 5 ppm cationic flocculant
Effect of anionic flocculant dosage and molecular weight on solids capture of harvested algae pretreated with 5 ppm cationic flocculant
Effect of cationic flocculant dosage and molecular weight on solids capture of harvested algae (0.456 g/L)
70
75
80
85
90
95
100
4 6 8 10 12 14
Solio
ds C
aptu
re, %
ppm
Cationic flocculant only
3-5M MW
5-7M MW
7-9M MW
9-11M MW
80828486889092949698
100
0 2 4 6 8 10 12
Solio
ds C
aptu
re, %
ppm
Cationic + anionic flocculant
8-12M MW
12-14M MW
18-24M MW
With 5 ppm cationic,5-7 M MW flocculant
Biomass Harvesting:Optimization of Flocculation Procedure
(Residence Time = 10 Min)
Heavy Metals Analysis
17
0.0054
0.0035 0.00310.0010
0.0100
0.00560.0050 0.0051
0.00390.0050
0.000 0.000 0.000
0.0000.002
0.0000 0.0000 0.00000.0018
0.0500
0.000
0.010
0.020
0.030
0.040
0.050
0.060
mg/
L
As
Cd
Hg
Se
Analysis of solids Analysis of nutrient broth in PBR
• “Metals from Nutrients” represents weighted calculation based on metals in dry nutrients and their respective target concentrations in algae media
• SDWA MCL’s represent the Maximum Contaminant Levels (MCL’s) for drinking water as regulated by the Safe Drinking Water Act of 1974
• 2015 averages are average of five samples of dry algae grown on flue gas at East Bend Station in 2015
• Weighted Dry Nutrients numbers represent the sum of all metals present in dry nutrients, weighted to reflect the nutrient mixture as it is added to the PBR
0.95
3.69
0.72
0.11 0.00
0.83
2.42
9.92
1.390.44
0.10
1.92
0.04 0.00 0.00 0.00 0.00 0.00
0.89 0.94
0.00 0.00 0.00 0.00
0.0
2.0
4.0
6.0
8.0
10.0
12.0
mg/
kg
As
Cd
Hg
Se
• Very low heavy metal concentrations detected in harvested algae – levels are consistent with heavy metals incorporation from supplied nutrients
18
Schematic of a section of the algae system consisting of 52 PBR modules, 4 settling tanks (ST), holding tanks (HT), and UV sterilizers (UV).
A schematic of the algae system (260 PBR modules; 260 individual feed tanks, feed pumps, and compressors; 20 individual settling tanks, holding tanks, and UV sterilizers)
• A life cycle assessment (LCA) was developed for an algae system based on UK’s cyclic flow PBR, mitigating 30% of the CO2 emitted by a 1 MW coal-fired power plant.
• Operation of the algae system included cumulative process requirements and energy consumption associated with algae cultivation, harvesting, dewatering, nutrient recycling, and water treatment.
Life Cycle Assessment
19
-6.1E+04
7.6E+031.8E+031.2E+032.9E+03
6.3E+033.5E+031.4E+03
8.7E+03
1.9E+03
-2.6E+04
-70000
-60000
-50000
-40000
-30000
-20000
-10000
0
10000
20000
Target CO2 capture
PET acquisition
PVC acquisition
PBR tank construction
Settling and holding tanks construction
Comm
erical fertilizers
N2O
emission from
fertilizer
Water treatm
ent (sterilization)
Compressor
Pump requirem
ent (PBR system)
Net CO
2 emission (PBR system
)
MTC
O2
• CO2 emission associated with the gas compressor was 8.7 x 103 metric tons, due to the large amount of flue gas (4422 m3/h) being compressed at full capacity for 12 h per day.
• PBR feed pumps emitted a lesser amount of CO2 (1.9 x 103 metric tons) on account of the cyclic flow operation mode.
• The PBR system was able to capture 43% (2.6 x 104 metric tons) of the target CO2 emission (6.1 x 104
metric tons).• The LCA results demonstrate that a
PBR algae system can be considered as a CO2 capture technology.
POWER PLANTCapacity 1 MWCO2 emission 22.76 ton/day
CO2 capture 30 %
CO2 emission mitigated 6.83 ton/dayOperation 300 day/yearALGAEStrain Scenedesmus acutusGrowth rate 0.15 g/L/dayCulture density at harvest 0.8 g/L (dry weight)Algae required for 30% CO2 capture 3.88 ton/day
Life Cycle Assessment:Results
SUMMARY
Techno-economic Analysis
20
Heat rate(kg CO2/mw-hr)
Capacity(Megawatt)
kg CO2/yr
CO2 conversion /algae production
CAPEXPBR
DewateringInfrastructure
Etc.
OPEXEnergy
MaintenanceDewatering
NutrientsEtc.
X carb X protein X lipid
Utilization $/ (kg* year) (+)
Operating DaysSpeciesSunlight
(PAR/m^2)
kg algae/yr
$/ (kg* year) (-) EconomicFeasibility
UncertaintiesCO2 credit?
Local Economic Impact?
981
300
1 MW
212 kton/yr
Scenedesmus sp.1.78 ton CO2/ton algae 3,968,090 kg/yr
$ 1,703,935 / yr $1,769,317 /yr
$875 /ton
US Scenario (best case):• 30% CO2 capture• Algae productivity = 35 g/m2.day• 300 operating days/yr• 30 yr amortization• Cost of capital not included
Base case: 1 MW coal-fired power plant Estimated min. algae production cost = $875/ton(biomass dewatered to 10-15 wt% solids)
21
Techno-economic Analysis (cont.)
$0$500
$1,000$1,500$2,000$2,500$3,000$3,500$4,000$4,500$5,000
0 10 20 30 40 50 60 70 80 90
$ /
ton
biom
ass
g/ (m^2* Day)
$/ TON ALGAE
US 2017 PRC 2017
Decreased capital cost
• Cost estimates (2017) are consistent with projections from prior analysis (2013), showing considerable progress toward economic viability
• Asymptote relates to operating costs
Operating costs;note asymptote
Bioplastics ($400-1200?/ton)Animal Feed / Aquaculture ($400-700/ton)
Liquid Fuels (⁓$300/ton)
Human and Animal Feed Supplements
($800-$1200/ton)
NutraceuticalsCosmetics
Food Products
FDARegulated
Applications
Algal Biomass Utilization
22
Product/extract Selling price Wt% in algaeβ-carotene $300-3000/kg 14%Astaxanthin $2500-7150/kg 3%DHA (>70% Pure) ~$12,540/kg 7.8%EPA (>70% Pure) ~$12,540/kg 4%
EPA
DHA
Astaxanthin
β-carotene
Increasing value
Increasing market
size
Lipid Extraction and Characterization
23
• Wet Scenedesmus, typically ~15 wt% solids
• Ultrasound, microwave irradiation and bead beating all proved ineffective for cell lysing
• Acidification to pH 1-2 using aq. HCl/MeOH results in cell lysing and simultaneous lipid (trans)esterification*
• Yield of esterifiable lipids = 6.3 (+/- 0.1) wt%, close to value reported previously for dry Scenedesmus**
• Lipids from this strain of Scenedesmusacutus are highly unsaturated: ALA (α-linolenic acid) accounts for almost 50% of total lipids
* L.M.L. Laurens, M. Quinn, S. Van Wychen, D.W. Templeton, E.J. Wolfrum, Anal. Bioanal. Chem., 403 (2012) 167-178. **E. Santillan-Jimenez, R. Pace, S. Marques, T. Morgan, C. McKelphin, J. Mobley, M. Crocker, Fuel 180 (2016) 668-678.
0
5
10
15
20
25
30
35
40
45
50
Con
tent
(w
t%)
24
75 wt% algal FAMEs in dodecane, WHSV = 1 h-1, Temp. = 375 °C
0
10
20
30
40
50
60
70
80
90
100
0 10 20 30 40
Mas
s (%
)
Time (h)
FAMEs and other Esters
Alcohols
Diesel-like (C10-C20) hydrocarbons
Heavier (C21-C28) hydrocarbons
Fatty Acids 90
91
92
93
94
95
96
97
98
99
100
Inco
nden
sabl
e G
asC
ompo
siti
on (
%)
n-Butane Propane Ethane Methane Hydrogen
• >90% liquid products are diesel-like hydrocarbons at all reaction times• Methane yield decreases after induction period, indicating poisoning of cracking sites
Upgrading of Extracted Algal FAMES to Hydrocarbons
20% Ni – 5% Cu/Al2O3 catalyst
E. Santillan-Jimenez, R. Loe, M. Garrett, T. Morgan, M. Crocker, Catal. Today, 2017, http://dx.doi.org/10.1016/j.cattod.2017.03.025.
Composition of Whole and Defatted Algae
25
Sample Ash (wt%) Protein (wt%) Volatiles (GC/MS)
Whole 11.1 44.2 16 peaks at 140 °C; 196 peaks at 200 °C
Defatted 15.6 50.7 12 peaks at 140 °C; 121 peaks at 200 °C
Increase in protein and ash content consistent with removal of lipids
Fewer compounds were released upon heating to 200 °C for the defatted algae, suggesting that lipid extraction may have improved thermal stability
Defatted algal biomass has improved odor properties
Defatted algae used for production of maleic anhydride compatibilized EVA (ethylene vinyl acetate) composite, containing 30 wt% algae
EVA composite test parts
Summary (DE-FE0026396)
• Very low heavy metal concentrations detected in harvested algae – levels are consistent with heavy metals incorporation from supplied nutrients
• An improved protocol for algae harvesting was developed, based on the use of cationic + anionic flocculants
• LCA showed that the cyclic flow PBR qualifies as a net CO2 capture technology
• TEA indicates a best case scenario production cost of $875/ton for Scenedesmus acutus biomass
• A procedure was developed for lipid extraction from wet Scenedesmusbiomass
• Extracted lipids were upgraded to diesel-range hydrocarbons
• Defatted biomass possessed improved odor properties for bioplastic applications
26
DE-FE0029632: Technical Approach/Project Scope
27
Key Issues to be Resolved
28
1) Can algal biomass production costs be lowered by the use of a combined PBR + pond cultivation system?→ Combine the low capex of ponds with the high productivity of
PBRs→ Comparison of pond, PBR, and PBR/pond systems (TEA and LCA)
2) In the case of algae-based bioplastic production, which processing scheme offers the greatest potential for revenue generation and large-scale application? → Whole biomass vs. wet lipid extraction vs. combined algal
processing (CAP)
3) From a TEA and LCA perspective, which cultivation system and processing scheme(s) offer the greatest potential?
Advantages and Challenges
Ability to generate a valuable product, thereby off-setting costs of CO2 capture (potential for new industry)
No need to concentrate CO2 stream Potential to polish NOx and SOx emissions
Areal productivity such that very large algae farms required for significant CO2 capture
CO2 capture efficiency modest for conventional systems (<50%) Challenging economics: cost of algae cultivation is high (currently
>$1,000/MT), hence require high value applications for produced algae biomass
Market size generally inversely related to application value (hence risk of market saturation)
29
Technical Approach/Project Scope
Year 1: • Task 1: Project Management• Task 2: LCA and TEA
- develop engineering process model for ponds, PBR and PBR/pond hybrid system• Task 3: Algae Cultivation
- pond and PBR installation - pond operation: comparison of pond and PBR/pond hybrid system productivity- monitor hydrolysate quality and composition for pond and PBR/pond cultures
• Task 4: Biomass Processing- wet lipid extraction with carbohydrate recovery - combined algal processing evaluation- bioplastic compounding 30
PowerPlant
Photobioreactor
Dewatering #2
Dewatering #1
Pond
BiomassFractionation
Protein Bioplastics
Flue Gas (CO2)
Inoculum
Solar radiation;nutrients; make-up water
CO2lean gas
Recovered media (nutrients + H2O)
Fermentablecarbohydrates
Lipids
CO2lean gas
UV steril izer
31
Technical Approach/Project Scope (cont.)
Year 2: • Task 5: LCA and TEA II
- initial TEA- initial LCA
• Task 6: Algae Cultivation II: Demonstration - site preparation - PBR and pond operation - monitor culture health and identify potential contaminants
Task 7: Biomass Processing II: Valorization and Scale-up- market analysis – sugars and lipids - bioplastic material characterization and film/fiber demonstration
Year 3: • Task 8: LCA and TEA III: Refinement of Sustainability Modeling
- PBR temperature and growth modeling- resource assessment- data incorporation- technology gap analysis
Project Partners
• UK CAER (Prof. Mark Crocker): - Project management- Operation of PBR/pond systems, data collection and analysis- Biomass fractionation (CAP and wet lipid extraction processes)
• UK Horticulture (Prof. Seth Debolt):- Analysis of extractable sugars from Scenedesmus cultures- Genetic monitoring of species abundance in Scenedesmus cultures
• Colorado State University (Prof. Jason Quinn):- Engineering model development- TEA- LCA
• Algix LLC (Ashton Zeller): - Biomass characterization- Bioplastic compounding- Characterization of molded test specimens
32
Project Timeline
33
Tasks and Milestones Start End Cost Q 1 Q 2 Q 3 Q 4 Q 1 Q 2 Q 3 Q 4 Q 1 Q 2 Q 3 Q41.0 Project Management 6/1/2017 5/31/2020 $119,8451.1 Stakeholder Meetings1.2 Reporting 6/1/2017 5/31/2020Milestone 1: Project kick-off meeting2.0 LCA/TEA I 9/1/2017 2/28/2018 $76,1662.1 Engineering Process Modeling 9/1/2017 2/28/2018Milestone 2.1: Engineering system model completed 3.0 Algae Cultivation I: Lab/Pilot Scale Investigation 6/1/2017 5/31/2018 $192,9283.1 Pond Installation 6/1/2017 8/31/20173.2 PBR + Pond Operation 9/1/2017 2/28/20183.3 Monitor Hydrolystate Quality and Composition 12/1/2017 5/31/2018Milestone 3.1: Pond and PBR/pond systems operational4.0 Biomass Processing I: Biorefinery Concept Development 6/1/2017 5/31/2018 $109,4534.1 Optimization of Wet Lipid Extraction 6/1/2017 11/30/20174.2 Combined Algal Processing Evaluation 12/1/2017 5/31/20184.3 Bioplastic Compounding 12/1/2017 5/31/2018Milestone 4.2: > 50% sugars & >80% lipids recovered 5.0 LCA/TEA II 6/1/2018 5/31/2019 $149,3415.1 Initial Techno-economic Analysis 6/1/2018 11/30/20185.2 Initial Life Cycle Assessment 12/1/2018 5/31/2019Milestone 5.2: Initial LCA showing net CO 2 capture6.0 Algae Cultivation II: Demonstration 6/1/2018 5/31/2019 $211,7796.1 Site Preparation 6/1/2018 8/31/20186.2 PBR and Pond Operation 9/1/2018 2/28/20196.3 Monitor Culture Health and Identify Contaminants 12/1/2018 5/31/2019Milestone 6.1: Ponds and PBR/ponds installed at East Bend7.0 Biomass Processing II: Valorization and Scale Up 6/1/2018 5/31/2019 $133,2447.1 Market Analysis (sugars & lipids) 6/1/2018 11/30/20187.2 Bio-Plastic Material Characterization 12/1/2018 5/31/2019Milestone 7.2: Bioplastic fiber vs film comparison8.0 LCA/TEA III 6/1/2019 5/31/2020 $264,0378.1 PBR Temperature and Growth Modeling 6/1/2019 11/30/20198.2 Resource Assessment 12/1/2019 5/31/20208.3 Data Incorporation 9/1/2019 2/28/20208.4 Technology Gap Analysis 3/1/2020 5/31/2020Milestone 8.3: CO 2 capture cost & revenue stream quantifiedMilestone 8.4: Technology gap analysis complete
6/1/17-5/31/18 6/1/18-5/31/19 6/1/19-5/31/20Budget period 1 Budget period 2 Budget period 3
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Key Milestones – Year 1
Task Description Planned completion date
Status
Task 1: Project Management Kickoff meeting 6/30/2017Completed:
8/8/2017Task 3: Algae Cultivation Ponds installed at UK CAER 8/31/2017
Completed: 9/7/2017
Task 2: LCA and TEA Engineering process model developed
5/31/2018 No change
Task 4: Biomass Processing >80% lipids & >50% fermentable sugars recovered from algae
5/31/2018 No change
Success Criteria
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Decision Point Date Success Criteria
Algae productivity 5/31/2018 PBR/pond cultivation system demonstrated to show superior productivity to pond-only system
Fractionation of algal biomass
5/31/2019 (i) 10 lb of algae produced for utilization studies (ii) >80% lipids and >50% fermentable sugars recovered from algae
Validation of bioplastic properties
5/31/2019 At least one bioplastic formulated with defatted algae identified to be commercially viable based on material properties
Algae productivity 5/31/2019 >15 g/m2 algae production demonstrated for hybrid cultivation system using coal-derived flue gas
Life cycle assessment 5/31/2019 Life cycle assessment shows net positive greenhouse gas emission reduction
Techno-economic analysis 5/31/2020 Economic viability of proposed process demonstrated
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Technical Risks and Mitigation Strategies
Description of Risk Probability Impact Risk Management Mitigation and Response
StrategiesPond crashes due to contamination by rotifers or algal viruses
Moderate High Ponds to be sterilized after culture crash; continuous operation of PBR will allow for immediate pond re-seeding
Culture contamination due to invasive species in pond
High Moderate By maintaining high Scenedesmusculture density (by means of PBR “overseeding” strategy), major contamination will be minimized
Inclement weather (heat wave)
Low High Switch to warm weather algae strain
Algae meal from CAP unsuitable for bioplastics
Moderate Moderate Use algae meal obtained from wet lipid extraction
LCA shows process to be net CO2 positive
Low High Use results to inform process development (avoid processing steps with high CO2 emissions)
Task 2: Sustainability Modeling
System Modeling
Experimental Systems
Sustainability Modeling
PBR Fluid Dynamics
Coal Flue Gas Integration
Downstream Characterization
Multi-Pathway Assessment Multiple Scales
TEA LCA
Gas Exchange
Technology Integration
Resource Assessment
Growth Modeling: Methodology (CSU)• Correlate growth to moles of photons incident on culture• Adjust for:
– Culture concentration– Temperature– Light inhibition
• Temperature modeled dynamically as well
𝑑𝑑𝐶𝐶𝑥𝑥𝑑𝑑𝑑𝑑
=𝜑𝜑𝐿𝐿 � 𝜑𝜑𝑇𝑇 � 𝜑𝜑𝐶𝐶 � 𝑃𝑃 � ∅𝑝𝑝𝑝𝑝𝑝𝑡𝑡𝑝𝑝𝑝𝑝
𝑉𝑉− ⁄𝐷𝐷 𝑉𝑉 𝜌𝜌𝐶𝐶𝑝𝑝𝑉𝑉
𝑑𝑑𝑇𝑇𝑑𝑑𝑡𝑡
= ∑𝑄𝑄𝑝𝑝
• 𝜌𝜌: Culture density assumed similar to water (~1000 [kg/m3])• 𝜑𝜑𝐿𝐿 � 𝜑𝜑𝑇𝑇 � 𝜑𝜑𝐶𝐶 Light intensity, temperature, and concentration modifiers, [dimensionless]• 𝑃𝑃 : Rate of light incident in [uE/m2s]• ∅𝑝𝑝𝑝𝑝𝑝𝑡𝑡𝑝𝑝𝑝𝑝 : Biomass to photon correlation, g Biomass / mole photon• 𝑉𝑉 : Culture volume [ m3 ] • 𝐷𝐷 : Biomass loss rate, a function of temperature, light intensity, and mass of biomass in system, g/s• 𝑑𝑑𝐶𝐶𝑥𝑥
𝑑𝑑𝑡𝑡: Time derivative of biomass concentration, [g m-3 s-1]
• 𝑑𝑑𝑇𝑇𝑑𝑑𝑡𝑡
: Time derivative of system temperature (assumed homogeneous in space) [K / s]• ∑𝑄𝑄𝑝𝑝 : Sum of thermodynamic fluxes, [W/m2 * area] [Watts]• 𝐶𝐶𝑝𝑝 : Specific heat of the culture, assumed similar to water
Growth Modeling: Results in Progress
0
200
400
600
800
1000
1200
24-Jul 3-Aug 13-Aug 23-Aug 2-Sep 12-Sep
Biom
ass C
once
ntra
tion,
g
m-3
Harvest date
Experimental
Modeled
• Preliminary fitting gives mixed results • Much more to be done in terms of model refinement and data fitting
System Info:• 2 rows of tubes @ 36 tubes per row (72 tubes)• 1140 L total system volume
Improvements:• New PBR features several Chinese-made components:
o Pipe-cleaning pigs (A) are now mass produced.o PVC stubs (B1) used to mount the PET tubes now utilize
rubber O-rings (B2) instead of the previously used rubber bands, creating a more leak resistant connection.
• Improved gas delivery system with more consistent bubble column.
A.
B.
B1.
B2.
Task 3: Construction of Updated Cyclic Flow Photobioreactor
B1.
B2.
Task 3: Installation of Ponds
Ponds and cyclic flow PBR installed at UK CAER (10/6/2017)
• 4 x 1100 Liter raceway ponds were installed and commissioned in first week of September 2017, along with 200 Liter seed pond
• Total growing capacity now > 8,000 Liters:
• 2 x 1200 L cyclic flow• 4 x 1100 L ponds• 1 x 200 L seed pond• 2 x 150 L seed reactor• 1 x 800 L Varicon
biofence PBR
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Installation of Ponds: Algae Lab Systems (ALS) Water Quality Monitoring
Clockwise from top left: ALS Spark box, software interface, wireless calibration of probes, ALS and Commercial Algae Professionals working on system installation
• Latest technology integrated with growth systems to continuously monitor temperature, pH, dissolved oxygen, and optical density
• ALS Spark boxes are modular, swappable, and commute wirelessly to a central hub to facilitate data visualization and export
• Representatives from Commercial Algae Professionals and Algae Lab Systems were on site to help with the installation and to train CAER research staff
Growth Comparison Study
Operating Conditions• Open Pond System seeded from seed pond and operated traditionally in semi-batch mode, with
harvesting and dilution from 0.8 g/l to 0.2 g/l • PBR + Pond system will be harvested at 0.8 g/l to 0.1 g/l with an additional ‘over seed’ of 0.1 g/l from PBR• PBR system will then be harvested to match the other systems at 0.2 g/l• Similar data sets will be maintained for all systems
Task 4: Optimization of Algae Fractionation Process
• Lipids are isolated from wet algae biomass via in situ transesterification/esterification• 5 wt% HCl in methanol is used as pretreatment solvent (pH 1-2)• Lipids recovered via hexane washing, solids via filtration• Aqueous phase contains mainly dissolved sugars (with some protein)
• Yields of residual solid biomass and dissolved matter in aqueous phase can be tuned to a large degree
• Additional experiments will include variation of acid concentrations and complete analysis of products
Lipids Solid from aq. phaseResidual solid biomass
Summary of Progress to Date
• Work commenced on building model for algae growth in cyclic flow PBR
• 1100 L cyclic flow PBR installed at UK CAER, together with 4 x 1100 L ponds and monitoring equipment
• Culturing study initiated in mid-September
• DoE underway, with goal of optimizing wet lipid extraction process
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Next Steps
• Work to continue on development of engineering process model
• Continuation of productivity study for as long as weather allows (with start-up again at CAER in April)
• Completion of biomass fraction study, including analysis of fractions (fermentable sugar and lipid yields)
• NB. Productivity study to be transferred to East Bend in June 2018 (EB maintenance shutdown scheduled for March-May)
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Acknowledgements
• Department of Energy / National Energy Technology Laboratory
• University of Kentucky: Michael Wilson, Dr. Jack Groppo, Stephanie Kesner, Daniel Mohler, Robert Pace, Thomas Grubbs
• Colorado State University:Dr. Jason Quinn, Sam Compton
• Algix:Dr. Ashton Zeller, Ryan Hunt
• Duke Energy:Doug Durst
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