Assc. Prof. Dr. Truong VinhChemical Engineering Department, Nong Lam University HCM city

3th Forum Ha Noi 20-21 December 2012

Contents

i.i. Introduction to biodiesel and algaeIntroduction to biodiesel and algae..

ii.ii. Introduction to ethanol plantIntroduction to ethanol plant..

iii. Introduction to algal-biodiesel from ethanol plant.

iv.iv. Two-stage growing experiment in fresh waterTwo-stage growing experiment in fresh water..

v. Growing experiment in wastewater without stress treatment.

vi. Photobioreactor development.

vii. Discussion

viii.viii.Proposed growing model for large scale algal Proposed growing model for large scale algal production based on two-stage growing production based on two-stage growing methodologymethodology

ix. Conclusion

INTRODUCTION TO 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 biodiesel ?

INTRODUCTION TO ALGAE Why microalgae ?

Less land used => No food competition problemAlgae+CO2= Energy =>Less gas emission

•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

Crop Used to produce

Greenhouse gas emission (kg CO2/MJ produced)*

Estimated % crop land used

Corn Ethanol 81-85 157-262Sugar cane Ethanol 4-12 46-57Switch grass Ethanol -24 60-108Wood residue Ethanol,

BiodieselN/A 150-250

Soybeans Biodiesel 49 180-240Rapeseed, canola Biodiesel 37 30Algae Biodiesel -183 1-2(Source: Martha Groom, University of Washington; * Emissions produced during the growing, harvesting, refining and burning)

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

Cassava => Fermentation => Ethanol + CO2 + Waste water + Residual

Microalgae => Photobioreactor => biodiesel + glycerine + chlorophyll + Waste

Food color Antioxidant

FertilizerBiodegradableFilm

Ethanol Plant

Growing System

Biodiesel Plant

High NutritionCheap CO2 source

3. Production Process of biodiesel from algae in two-stage growing system

Dried biomass

Dry extraction

Oil separation

Wet biomass

Oil refining

Biodiesel Reaction

Product Separation

Biodiesel Purification

Glycerin Purification

Harvesting

Drying

Wet extraction

MethanolCatalyst

Algae seed production

Algae growth in photo-bioreactor

Treatments

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

3.2 GROWING WITH TREATMENT: results of experiment 2

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 Value UnitN total 438.2 mg/L

P total 40.94 mg/L

K 648 mg/L

Ca 9.02 mg/L

Mg 131.63 mg/L

Na mg/L

Fe 0.432 mg/L

Mn - mg/L

Cu - mg/L

Zn 0.14 mg/L

S 11.46 mg/L

Mo - mg/L

Co - mg/L

BOD5 106 mgO2/L

COD 345 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

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

Cell density, million/mL

20% 25% 30%

Fluores 54 85 7370 82 72

LED 63 85 7165 59 55

ANOVASource of Variation SS df MS F P-value F crit

Sample 123.65 1 123.6492 1.1925 0.3167 5.9874Columns 470.30 2 235.1511 2.2678 0.1847 5.1433Interaction 102.51 2 51.25278 0.4943 0.6328 5.1433Within 622.16 6 103.6933

Total 1318.617 11

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

4. Growing experiment in wastewater without stress treatment: benefit from waste and CO2

Basal mediumPrice, VND/L

medium

Nutrient saving from using waste

NaNO3 24.75 24.75 NaNO3CaCl2 • 2H2O 3.575 MgSO4 • 7H2O 8.25 8.25 MgSO4 • 7H2OK2HPO4 8.25 KH2PO4 28.875 NaCl 0.275 Total 73.975 33 45%

Year of experiment

BOD

(mgO2/L)

before/After

growing

COD

(mgO2/L)

before/After

growing

2009 81/7.9 260/78

2012 106/80 345/100

Contribution of CO2 and nutritent in waste water on cost saving to produce biomassSaving 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

ParametersLCP170-

D70LCP400-

D140LCP400-

D170LCP400-

D210

Tube diameter (D) of solar receiver (mm)

70 140 170 210

Total length of solar receiver (m)

44.0 26.0 17.6 11.5

Length of tube (m) 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

Velocity of culture (m/s) 0.01 7.5 8 8.5

Table 2: Summary of characteristics of different developed PBRS for experiments

5.2 PhotobioreactorsContamination controlSimple construction

LCP400-D17081 liter/m2

LCP400-D14070 liter/m2

Treatment system

5.2 PhotobioreactorsContamination controlSimple construction

LCP2500-D170:2.5 m3

Width x Length = 2.5 m x 15 m81 liter/m2

5.3 GROWING IN PBRS

The growing of algae Chlorella vulgaris in PBR LCP-170Initial number of cell was 106 cell/ml

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

The cost of oil

reduced by 4

times with

stress treatmen

t

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

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 coste)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 stage-Growing => Second stage-Treatment

Strategy: Using sun energy as sustainable resource for algal-

biodiesel 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.

Harvest - Seed culti. Harvest - Seed culti. Harvest - Seed culti.

Solar panel

Plastic houseLED light

Sun drying Sun dryingCultivation-outdoor

Cultivation-indoorPlastic house Plastic house

Plastic house

15m

17m

15m

Harvest - Seed cultivation. Harvest - Seed cultivation Harvest - Seed cultivation

Treatment Treatment Treatment

Treatment Treatment Treatment

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 VinhChemical Engineering DepartmentNona Lam University, Ho Chi Minh city, Vietnamtv@hcmuaf.edu.vn0903862721