MICRO –ALGAE AS A SOURCE OF BIO DIESEL: CHALLENGES AND FUTURE PROSPECTS

K.Sudhakar

Assistant professor, Energy Department, MANIT, Bhopal-462007, MP,India Dr. S. Suresh Assistant Professor, Department of Chemical Engg., MANIT, Bhopal-462007, MP, India Dr. (Mrs) M. Premalatha Associate Professor, CEESAT, NIT Trichi, TN, India Presented at All India Seminar On Energy Management Through Renewable Sources and Efficient technologies Institution of Engineers, Madhya Pradesh State Centre, Bhopal, 08-09 th Jan, 2011

‘Climate change poses a great challenge to our development prospects…....we need global response, a a local response’

national response

and -------

Hon. Dr. Manmohan Singh

Concerns for Global warming Current Assessment IPCC Assessment

First Report - 1990 Second Report - 1995 Third Report - 2001 Fourth Report - 2007 Average global temperature increase 1906-2005 – 0.74

o C Expected Temperature rise up to the Year 2100 2.4 to 6.4 o C Expected Sea Level rise 18 to 59 cm

Major and Minor Greenhouse Gases and Global Warming Potential

Major greenhouse gas concentrations of CO2, NOx, CFCs, Methane have increased 20-30% since pre industrial era

o o o The Energy generating plants atmospheric CO 2 concentrations.

contributes mostly to increasing CO 2 concentration increased from 280 ppm to 390 ppm in the present Average global temperature increase by 1.5-5 degree.

Coping with Global Warming

S C I E N T I F I C

Greenhouse Gases CAUSE Mitigation Strategy Renewable sources Energy Efficiency Clean Coal Technology CCS Earth Interactions Air interaction Global Warming EFFECT Climate Change Impacts -Adaptation Crop Productivity Frequent Disasters Water Scarcity Vector borne diseases

P R E D I C T I V E

The World’s Energy Resources Are Limited!

Why Micro-algae?

– High Growth rate – Minimal requirement – High efficiency resource Photosynthetic – Up to 70% of biomass is usable oils algae – does not compete for land and space with other agricultural crops – can survive in water of high salt content

Algae Growing Methods :

 What is needed  Sunlight   CO 2 Nutrients  Storage of Energy   Lipids and oils Carbohydrates Other Dependent parameters: Temperature , pH (Physical factors) Pathogen ,predation, competition (Biotic factors)

Algae Species and Typical oil content Micro algae

Botryococcus braunii Chlorella sp Crpthecodinium cohnii Cylindrotheca sp Dunalielia primolecta Isochryais sp Monallanthus salina Nannochloris sp Nannochloropsis sp Neochloris oleoabundans Nitzschina sp Schiochytrium sp Tetraseknus sueica

Oil content (% dry weight)

25-75 28-32 20 16-37 23 25-33 >20 20-35 31-68 35-54 45-47 50-77 15-23

Algae Open Pond

Algae Photo bioreactor

Algae cultivation

Open Pond & Photo Bioreactor Parameter

Construction

Open pond

Simple Cost Water losses Typical biomass concentration Temperature control Species control Contamination Light utilization C02 losses to atmosphere Typical Growth rate(g/m2 day) Area requirement Depth/diameter of water Surface: volume ratio Cheaper to construct, operate High Low, 0.1-0.2 g/L Difficult Difficult High risk Poor High Low:10-25 Large 0.3m

~6

Closed photo bioreactor

More complicated varies by design More expensive construction, operation Low High: 2-8 g/L Easily controlled Simple Low risk Very high Almost none Variable:1-500 Small 0.1m

60-400

Overview of micro-algae technology for carbon sequestration and bio-diesel production

Algal Biotechnology Converts Flue Gases & Sunlight into Biofuels through Photosynthesis “Used” Algae have Multiple Potential Uses

Power Plant / Energy Source

Sunlight

Photo bioreactor Cleaned Gases Flue Gases

NOx + CO 2 from combustion flue gas emissions Algal Biotechnology

Co-Firing Esterification Fermentation Green Power Biodiesel Ethanol Protein Meal

Closed Cycle Biomass Carbon Management Fuel Carbon (100%) Open Cycle Carbon Clean Gases Fuel Carbon (60%) Algae Biomass as Fuel Source (40% Fuel Carbon) Closed Cycle Carbon Management

Algae growth and harvesting process

INITIAL PLAN OF WORK

• Laboratory Phase: Techniques presently in use will be tested & optimized in laboratory, and most feasible techniques will be identified for the available conditions • Testing Phase: Techniques identified in the lab will be scaled up to the semi-pilot scales, exposed to environmental conditions present and Improvements will be made as required • Utilisation Phase: to produce Bio-Diesel The process identified will be used

Open pond for algae cultivation Spectrophotometer Magnetic Stirrer pH Measurement device

Laminar Flow chamber Algae Strains Algae Strains Gas chromatography

Limits to productivity of Microalgae

•

Physical factors such as light (quality and quantity), temperature, nutrient, pH, O CO 2 2 and

•

Biotic factors including pathogens, predation and competition by other algae, and

•

Operational factors such as: shear produced by mixing, dilution rate, depth and harvest frequency

Physical factors

• Climate

– Cold weather reduces algae oil production – Optimum temperature: 25-29 0 C

• Nutrients

– Nitrogen & phosphorus: 0.8% and 0.6% of volume of pond

• Light

– High pressure sodium & Metal halide lamp

• CO

2 – Optimum supply of CO 2 during day time

Algae harvesting • Microfiltration • Centrifugation • Flocculation • Sonochemical • Solvent Extraction and others.

Table. Theoretical estimation of biodiesel from algae Yield/day (g dry weight/day) 40% oil content (g/day) Oil content can go up if growth conditions optimize 60 24 Density = 0.9g/mL Assumed 1:1 ratio between oil content and diesel

Small scale production of biodiesel • Combine 4 g NaOH (Lye) with 250 ml CH 3 OH (Methanol) to form CH 3 O (Methoxide).

• Mix until NaOH is completely dissolved in CH 3 OH (approx.1 min).

• Combine CH 3 O with warm (60˚C) oil.

• Thoroughly agitate (roughly 5-10 min) • Allow resulting mixture to settle into layers (roughly 8 hours until fully settled)

Algae Biodiesel Carbon Credits

1L of diesel = 2.67 Kg of CO 2 Ref: http://www.epa.gov/otaq/climate/420f05001.htm

1L of Biodiesel = 0.58 Kg of CO 2 Ref: http://www.epa.gov/otaq/climate/420f05001.htm

1L of Biodiesel will save 2.09 Kg of CO 2 Biodiesel reduces net emissions of CO 2 by 78.45% Ref:NREL/SR-580-24089 UC Category 1503 100 Mega L of Biodiesel will save 209 Kt of CO 2

Summary

• Micro-algae biodiesel is a newly-emerging field • Algae is a very efficient means of producing biodiesel and oil production from algae farms is feasible and scalable • By coupling algae production with a CO 2 pollution control process, the economic viability of micro algal based biodiesel is significantly improved • Genetic Engineering and advancement in the design of bioreactor can improve the productivity of micro algae • Further research necessary for economic production of biodiesel from algae.

A N Y Q U E S T I O N S

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