3th Forum Ha Noi 20-21 December 2012
Assc. Prof. Dr. Truong Vinh
Chemical Engineering Department, Nong Lam University HCM city
Contents
i.
ii.
iii.
iv.
v.
Introduction to biodiesel and algae.
Introduction to ethanol plant.
Introduction to algal-biodiesel from ethanol plant.
Two-stage growing experiment in fresh water.
Growing experiment in wastewater without stress
treatment.
vi. Photobioreactor development.
vii. Discussion
viii.Proposed growing model for large scale algal
production based on two-stage growing
methodology
ix. Conclusion
INTRODUCTION TO BIODIESEL
Why biodiesel ?
1. The resources of fossil fuel is expected to be
reduced in the next decades.
2. Consumption of diesel is 6 times of petrol.
Combustion of fossil diesel produces CO2 causing
global warming: 240ppm to 345ppm during the 20th
century.
3. Need to replace fossil fuel by other sources of
energy: wind, solar, biodiesel.
4. Biodiesel is one of the renewable energy resources
(wind, solar can not be used directly for transport).
5. Direct use of biodiesel in diesel engine is cleaner
than fossil diesel: less emission of greenhouse gas
such as CO, CO2, SO2, NOx.
Why microalgae ?
INTRODUCTION TO ALGAE
 Less land used => No food competition problem
 Algae+CO2= Energy =>Less gas emission
Crop
Corn
Sugar cane
Switch grass
Wood residue
Soybeans
Rapeseed, canola
Algae
Used to
produce
Ethanol
Ethanol
Ethanol
Ethanol,
Biodiesel
Biodiesel
Biodiesel
Biodiesel
Greenhouse gas emission
(kg CO2/MJ produced)*
81-85
4-12
-24
N/A
Estimated % crop
land used
157-262
46-57
60-108
150-250
49
37
-183
180-240
30
1-2
(Source: Martha Groom, University of Washington; * Emissions produced during the growing, harvesting, refining and burning)
•Oil crops, waste cooking oil and animal fat : a potential renewable, carbon
neutral fuels, available technology, food competition problem
•Microalgae: high productivity, less competition with feed crop, less CO2
emission => renewable resources of energy that has the potential to
completely displace fossil diesel
1. INTRODUCTION TO ETHANOL PLANT
1. Name of company: Green Field Join Stock Company
2. Location: Quang Nam Province, Vietnam
3. Specification of the ethanol plant:
 Ethanol production: 100,000 ton/year
 Waste water release: 4000 m3/day
 Cooling water release: this river water used to
cool the ethanol distillation equipment with the
rate of 8000 m3/day at temperature of 60oC.
 CO2 resource: fermentation of cassava produced
20,000 ton CO2/year
2. INTRODUCTION TO algal-biodiesel from
ethanol plant
Ethanol Plant
Cheap CO2
source
High Nutrition
Cassava => Fermentation => Ethanol + CO2 + Waste water + Residual
Microalgae => Photobioreactor => biodiesel + glycerine + chlorophyll + Waste
Growing System
Biodegradable
Film
Food color
Antioxidant
Biodiesel Plant
Fertilizer
3. Production Process of biodiesel from algae in
two-stage growing system
Dry extraction
Oil separation
Harvesting
Drying
Second stage of
growing
Dried biomass
Wet biomass
Wet extraction
Treatments
Biodiesel Reaction
Product
Separation
Biodiesel
Purification
Methanol
Catalyst
Glycerin
Purification
First stage of growing
Oil refining
Algae growth in photobioreactor
Algae seed production
3.1 GROWING WITHOUT TREATMENT
Composition
Percentage
Protein
60.1
Lipid
14.55
Carbonhydrates
0.36
Chlorophylls
0.0013
Carotenoids
0.0059
Total
75.02
Composition of algae grown without treatment
is suitable for Functional Food
3.1 GROWING WITH TREATMENT
Methodology:
Experiment 1:
• Growing in Basal medium for 7 days
• Transfering to new medium contained 15,
30, 45, and 60 % Basal nutrient. The control
sample was the 100% Basal medium
• Continueing to grow for 7 days and harvest
Experiment 2:
Best result from experiment 1 was used with
modification of Basal medium and variation
of initial cell density
3.2 GROWING WITH TREATMENT:
results of experiment 1
Effect of stress nutrient treatment on biomass and oil productivity after
7 days
.500
2.500
.472
.450
Oil content, g/L
.350
.300
2.000
.364
.316
.290
.278
.276
.272
1.500
.250
.206
.200
1.000
.150
.100
.500
.050
.000
.000
15% nutrient
30% nutrient
45% nutrient
Crude oil, g/L
Refined lipid, g/L
60% nutrient
Biomass, g/L
Control
Biomass, g/L
.400
.403
.394
3.2 GROWING WITH TREATMENT:
results of experiment 2
Effect of initial cell density on the biomass and oil content at 30%
nutrient stress treatment
70.000
60.130
60.000
0.246
50.000
0.250
0.232
0.218 50.350
0.200
40.000
0.156
0.149
30.150
30.000
34.560
0.150
27.870
0.100
20.000
0.050
10.000
0
.000
3
8(0)
8(1)
0
0
0.000
8(2)
15
25
Initial cell density, million/L
8(0): Basal , 8(1): Modified 1 , 8(2): Modified 2
% dầu
g dầu/L
Lipid Productivity, g/L
53.522
Crude oil content, %
0.300
0.280
3.2 GROWING WITH TREATMENT:
Conclusion
• Nutrient stress treatment decreased the biomass but
improved the oil content compared to the control.
• At the treatment 30% of Basal nutrient (in equivalent to
deprivation of 70% of nutrient), oil content was highest with
crude oil of 0.47 g/L and refined oil of 0.36 g/L.
• At the treatment 30% of Basal medium, with additional of
MgSO4 (Modified 1) and initial cell density of 8 106/mL, the
oil content was 60%.
4. Growing experiment in wastewater
without stress treatment
Nutrient in waste water of ethanol plant
Item
N total
P total
K
Ca
Mg
Na
Fe
Mn
Cu
Zn
S
Mo
Co
BOD5
COD
Value
438.2
40.94
648
9.02
131.63
Unit
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
0.432
0.14
11.46
106
345
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mgO2/L
mgO2/L
4. Growing experiment in wastewater
without stress treatment
Experimental design: the waste water was dilute
with variation of the ratio between waste water and
fresh water/cooling water from 20% to 100% (v/v)
as in shown the following table:
Treatment
20w
40W
60w
80w
100w
Waste
water
20
40
60
80
100
Fresh water
80
60
40
20
0
Growth condition: container 1.5 liter, fluorescent light with light
intensity of 110 μmol/m2s using 4 fluorescent lamps of 40W
4. Growing experiment in wastewater
without stress treatment: results
Cell density, x106/mL
250
200
100 w
150
80 w
60 w
100
40 w
20 w
50
0
0
5
10
15
Growing time, day
20
4. Growing experiment in wastewater without
stress treatment: oil content and biomass
• The algae could not survive in the media that
contained higher 60% of waste water.
• At 20% of waste water, the algae grew well and
better than in normal Basal medium. The cell
density was 230 million/mL after 14 days of
growing. The productivity of algae grown in 20%
waste was 3.5g/L with crude oil content of 57%
4. Growing experiment in wastewater without
stress treatment: Using LED light
Experimental design:
• The waste water /cooling water of 20% , 25% and
30% (v/v) was used as nutrients for algal growing
• Two sources of light were compared: fluorescent
light (4 lamps of 40W) and LED light (4 lamps of 21 W)
• Algae were grown in 1.5 liter bottles.
4. Growing experiment in wastewater without
stress treatment: Using LED light
Results: No significant different between cell density of algae
grown under fluorescent and LED light after 8 days (P>0.05)
Waste
content
Fluores
LED
ANOVA
Source of Variation
Sample
Columns
Interaction
Within
Total
Cell density, million/mL
20%
25%
30%
54
85
73
70
82
72
63
85
71
65
59
55
SS
123.65
470.30
102.51
622.16
df
1
2
2
6
1318.617
11
MS
123.6492
235.1511
51.25278
103.6933
F
P-value F crit
1.1925 0.3167 5.9874
2.2678 0.1847 5.1433
0.4943 0.6328 5.1433
4. Growing experiment in wastewater without
stress treatment: Using LED light
Results: the algae growed best at 25% of waste water for both light sources
=> using LED light saved half of energy
90
Cell density, x106/mL
80
70
60
50
Fluoresence
40
LED light
30
20
10
0
20% waste 25% waste 30% waste
4. Growing experiment in wastewater without
stress treatment: benefit from waste and CO2
Nutrient saving
Price, VND/L from using
waste
medium
24.75 24.75
NaNO3
3.575
Basal medium
NaNO3
CaCl2 • 2H2O
MgSO4 •
7H2O
8.25
K2HPO4
8.25
KH2PO4
28.875
NaCl
0.275
Total
73.975
8.25 MgSO4 • 7H2O
33
Year of
BOD
experiment (mgO2/L)
before/
After
growing
COD
(mgO2/L)
before/
After
growing
2009
81/7.9
260/78
2012
106/80
345/100
45%
Contribution of CO2 and nutritent in waste water on cost saving to produce biomass
Saving from CO2
Saving from nutrient of waste water
39.9
1.5
5. PHOTOBIOREACTOR DEVELOPMENT
Purpose:
 Cheap price: plastic material for tube
 Contamination control: closed system
 Low operation cost: minimal pump energy
5.1 Photobioreactor parameters
Table 2: Summary of characteristics of different developed PBRS for experiments
LCP170D70
LCP400D140
LCP400D170
LCP400D210
70
140
170
210
44.0
26.0
17.6
11.5
2.0
3.5
3.0
3.0
Total area occupied (m2)
4.0
5.7
4.9
3.6
Volume of culture (liter)
168
400
400
400
Air lift column height (m)
0.45
0.7
0.7
0.7
Tank height from tube (m)
1
1.4
1.4
1.4
0.01
7.5
8
8.5
Parameters
Tube diameter (D) of solar
receiver (mm)
Total length of solar
receiver (m)
Length of tube (m)
Velocity of culture (m/s)
5.2 Photobioreactors
Contamination control
Simple construction
LCP400-D170
81 liter/m2
LCP400-D140
70 liter/m2
Treatment system
5.2 Photobioreactors
Contamination control
Simple construction
LCP2500-D170:
2.5 m3
Width x Length = 2.5 m x 15 m
81 liter/m2
5.3 GROWING IN PBRS
The growing of algae Chlorella vulgaris in PBR LCP-170
Initial number of cell was 106 cell/ml
60
Cell density, 106/mL
50
40
30
20
10
0
0
100
200
300
400
Growing time, (h)
500
600
Figure 4: Algae density and OD of Chlorella vulgaris as function of growing time
5.4 DISCUSSION
Comparison of biomass cost produced from PBRs of
different tube sizes of experimental systems with and
without treatment
D, mm
210
170
140
70
Biomass, g/L
0.336
0.35
0.41
0.67
Crude Oil, mg/L
36.6
70.9
80
80.4
CD, x106 cell/mL
27
47.5
38
125
Specific volume, L/m2
89.3
81.1
70.0
40.4
Capacity, g oil/m2
3.27
5.75
5.60
3.25
VND/g oil (without treatment)
423
425
447
1153
VND/g oil (with treatment)
107.6
The cost of
oil
reduced by
4 times
with stress
treatment
a)Microalgae is renewable resource of energy
that has the potential to displace fossil diesel
b)Technology should be improved to reduce cost
by improving of algae strain, growing
methodology.
c)Wet extraction or solar drying should be
considered to reduce the production cost
d)Growing in waste water using CO2 of ethanol
plant provided high productivity and reduced
production cost
e)Growth methodology in PBR should be
combined with stress treatment (two stage
growing) to optimize the biodiesel production
from microalgae.
Methodology: Two-stage growing technology: First stageGrowing => Second stage-Treatment
Strategy: Using sun energy as sustainable resource for algalbiodiesel production : Combination between direct sun light
and solar panels as electrical source for LED light in order to
stabilize the light source during the year.
Solar panel
First stage
LED light
Sun drying
Plastic house
Plastic house
Cultivationoutdoor
Cultivationindoor
Sun drying
Plastic house
17m
Plastic house
Harvest - Seed culti.
Harvest - Seed culti.
15m
15m
Harvest - Seed culti.
Second stage
Treatment
Treatment
Harvest - Seed cultivation.
Treatment
Treatment
Harvest - Seed cultivation
Treatment
Treatment
Harvest - Seed cultivation
 Initial results of project EEP-3-V-053 indicated that waste water of
ethanol can be used as nutrient for algal growth to produce biodiesel
with a contribution to cost saving of 1.5%.
 Using the available CO2 source produced from ethanol plant
decreased the production cost by 40%.
 Autotrophic growth of algae for biodiesel is sustainable because it
uses sun as energy.
 However, sun energy is not stable for algal growing due to the
weather change during the year
 Therefore, solar panel is propose to stablise the light source
 LED light is expected to use to reduce the investment of the solar
panels.
 Two – stage growing method can be used to enhance the oil content.
 Energy used in extraction of oil from algae is reduced significantly by
either wet extraction method or sun drying/solar drying.
 The improvement of other technologies such as plastic material for
tubes of PBR, efficiency of LED light, solar panel, etc, is important
Contact adress:
Truong Vinh
Chemical Engineering Department
Nona Lam University, Ho Chi Minh city, Vietnam
tv@hcmuaf.edu.vn
0903862721