algae energy.pdf

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Green Energy and Technology


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Ayhan Demirbas M. Fatih Demirbas

Algae Energy

Algae as a New Source of Biodiesel

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Ayhan Demirbas

Professor of Energy Technology

Sirnak University

Sirnak

Turkey

M. Fatih Demirbas

Sila Science and Energy Unlimited Company

University Mah.

24 Akif Saruhan Cad., Mekan Sok.

61080 Trabzon

Turkey

ISSN 1865-3529ISBN 978-1-84996-049-6 e-ISBN 978-1-84996-050-2

DOI 10.1007/978-1-84996-050-2

Springer London Dordrecht Heidelberg New York

British Library Cataloguing in Publication DataA catalogue record for this book is available from the British Library

Library of Congress Control Number: 2010929649

Springer-Verlag London Limited 2010Apart from any fair dealing for the purposes of research or private study, or criticism or review, as per-

mitted under the Copyright, Designs and Patents Act 1988, this publication may only be reproduced,stored or transmitted, in any form or by any means, with the prior permission in writing of the publish-ers, or in the case of reprographic reproduction in accordance with the terms of licenses issued by theCopyright Licensing Agency. Enquiries concerning reproduction outside those terms should be sent tothe publishers.The use of registered names, trademarks, etc., in this publication does not imply, even in the absence of aspecific statement, that such names are exempt from the relevant laws and regulations and therefore freefor general use.The publisher and the authors make no representation, express or implied, with regard to the accuracyof the information contained in this book and cannot accept any legal responsibility or liability for anyerrors or omissions that may be made.

Cover design:WMXDesign, Heidelberg, Germany

Printed on acid-free paper

Springer is part of Springer Science+Business Media (www.springer.com)


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Preface

This book examines the production of algae culture and usage of algal biomass

conversion products. In this book, the modern biomass-based transportation fuels

biodiesel, bio-oil, biomethane, biohydrogen, and high-value-added products from

algae are briefly reviewed. The most significant distinguishing characteristic of algal

oil is its yield and, hence, its biodiesel yield. According to some estimates, the yield

(per acre) of oil from algae is over 200 times the yield from the best-performing

plant/vegetable oils. The lipid and fatty acid contents of microalgae vary in accor-

dance with culture conditions. The availability of algae and the advantages of algal

oil for biodiesel production have been investigated.

Billions of years ago the Earths atmosphere was filled with CO2. Thus there was

no life on Earth. Life on Earth started with Cyanobacteriaand algae. These hum-

ble photosynthetic organisms sucked out the atmospheric CO2 and started releasing

oxygen. As a result, the levels of CO2 started decreasing to such an extent that life

evolved on Earth. Once again these smallest of organisms are poised to save us from

the threat of global warming.

In the context of climatic changes and soaring prices for a barrel of petroleum,

biofuels are now being presented as a renewable energy alternative. Presently, re-

search is being done on microscopic algae, or microalgae, which are particularly

rich in oils and whose yield per hectare is considerably higher than that of sun-flower or rapeseed. Algae will become the most important biofuel source in the near

future. Microalgae appear to be the only source of renewable biodiesel that is capa-

ble of meeting the global demand for transport fuels. Microalgae are theoretically

a very promising source of biodiesel.

Algae are the fastest-growing plants in the world. Industrial reactors for algal

culture are open ponds, photobioreactors, and closed systems. Algae are very im-

portant as a biomass source and will some day be competitive as a source for bio-

fuel. Different species of algae may be better suited for different types of fuel. Algae

can be grown almost anywhere, even on sewage or salt water, and does not requirefertile land or food crops, and processing requires less energy than the algae pro-

vides. Algae can be a replacement for oil-based fuels, one that is more effective

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vi Preface

and has no disadvantages. Algae are among the fastest-growing plants in the world,

and about 50% of their weight is oil. This lipid oil can be used to make biodiesel

for cars, trucks, and airplanes. Microalgae have much faster growth rates than ter-

restrial crops. the per unit area yield of oil from algae is estimated to be between

20,000 and 80,000 L per acre per year; this is 7 to 31 times greater than the next

best crop, palm oil. Most current research on oil extraction is focused on microalgae

to produce biodiesel from algal oil. Algal oil is processed into biodiesel as easily

as oil derived from land-based crops. Algae biomass can play an important role in

solving the problem of food or biofuels in the near future.

Microalgae contain oils, or lipids, that can be converted into biodiesel. The idea

of using microalgae to produce fuel is not new, but it has received renewed attention

recently in the search for sustainable energy. Biodiesel is typically produced from

plant oils, but there are widely voiced concerns about the sustainability of this prac-

tice. Biodiesel produced from microalgae is being investigated as an alternative to

using conventional crops such as rapeseed; microalgae typically produce more oil,

consume less space, and could be grown on land unsuitable for agriculture.

Using microalgae as a source of biofuels could mean that enormous cultures of

algae are grown for commercial production, which would require large quantities of

fertilizers. While microalgae are estimated to be capable of producing 10 to 20 times

more biodiesel than rapeseed, they need 55 to 111 times more nitrogen fertilizer

8 to 16 tons/ha/year.

This book on algae energy attempts to address the needs of energy researchers,

chemical engineers, chemical engineering students, energy resource specialists, en-

gineers, agriculturists, crop cultivators, and others interested in practical tools forpursuing their interests in relation to bioenergy. Each chapter in the book starts with

basic explanations suitable for general readers and ends with in-depth scientific de-

tails suitable for expert readers. General readers include people interested in learn-

ing about solutions to current fuel and environmental crises. Expert readers include

chemists, chemical engineers, fuel engineers, agricultural engineers, farming spe-

cialists, biologists, fuel processors, policymakers, environmentalists, environmental

engineers, automobile engineers, college students, research faculty, etc. The book

may even be adopted as a textbook for college courses that deal with renewable

energy or sustainability.

Trabzon, TURKEY (September 2009) Ayhan Demirbas

Muhammet Demirbas


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Contents

1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

1.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

1.2 Energy Demand and Availability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

1.2.1 Fossil Energy Sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

1.2.2 Renewable Energy Sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

1.3 Present Energy Situation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

1.3.1 Energy Production and Future Energy Scenarios . . . . . . . . . . 12

1.3.2 Future Energy Scenarios . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

2 Green Energy Facilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

2.2 Biomass Feedstocks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

2.3 Green Energy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

2.4 Importance of Biomass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

2.5 Production of Fuels and Chemicals from Biomass . . . . . . . . . . . . . . . 36

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

3 Biofuels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 493.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

3.2 Importance of Biofuels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

3.3 Bioethanol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

3.4 Biodiesel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

3.5 Bio-oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

3.6 Biogas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

3.7 FischerTropsh Liquids from Biorenewable Feedstocks . . . . . . . . . . . 64

3.8 Biohydrogen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69

3.9 Other Liquid Biofuels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 703.9.1 Glycerol-based Fuel Oxygenates for Biodiesel

and Diesel Fuel Blends . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70

3.9.2 P-series Fuels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

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3.9.3 Dimethyl Ether . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

3.9.4 Other Bio-oxygenated Liquid Fuels . . . . . . . . . . . . . . . . . . . . . 72

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72

4 Algae Technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75

4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 754.1.1 Definition of Algal Terms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76

4.2 Production Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77

4.2.1 Harvesting Microalgae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79

4.2.2 Photobioreactors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80

4.2.3 Open-pond Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83

4.2.4 Closed and Hybrid Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . 87

4.3 Production Costs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93

5 Energy from Algae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97

5.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97

5.1.1 Historical Perspective . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99

5.2 Biofuels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99

5.2.1 Biodiesel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102

5.2.2 Bioalcohol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104

5.2.3 Costs, Prices, and Economic Impacts of Biofuels . . . . . . . . . . 106

5.2.4 Environmental Impacts of Biofuels . . . . . . . . . . . . . . . . . . . . . 110

5.2.5 Combustion Efficiencies of Biofuels . . . . . . . . . . . . . . . . . . . . 113

5.2.6 Bio-oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117

5.2.7 Biomethane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119

5.2.8 Production of Bio-oil and Hydrogen by Pyrolysis . . . . . . . . . 120

5.2.9 Anaerobic Biohydrogen Production . . . . . . . . . . . . . . . . . . . . . 125

5.3 Liquefaction of Algal Cells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127

5.3.1 Liquefaction of Algal Cells by Hexane Extraction . . . . . . . . . 129

5.4 High-value-added Products from Algae . . . . . . . . . . . . . . . . . . . . . . . . 131

5.4.1 Small Molecules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131

5.4.2 Polymers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132

5.4.3 High-value Oils. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133

6 Biodiesel from Algae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139

6.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139

6.2 Biodiesel from Algal Oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140

6.2.1 Production of Biodiesel from Algal Oils . . . . . . . . . . . . . . . . . 144

6.3 Potential of Microalgal Biodiesel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147

6.4 Acceptability of Microalgal Biodiesel . . . . . . . . . . . . . . . . . . . . . . . . . 150

6.5 Economics of Biodiesel Production . . . . . . . . . . . . . . . . . . . . . . . . . . . 1516.6 Improving Economics of Microalgal Biodiesel . . . . . . . . . . . . . . . . . . 153

6.7 Advantages and Disadvantages of Biodiesel from Algal Oil . . . . . . . 153

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154


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Contents ix

7 Biorefineries. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159

7.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159

7.2 Definitions of Biorefinery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162

7.2.1 Main Technical and Nontechnical Gaps

and Barriers to Biorefineries . . . . . . . . . . . . . . . . . . . . . . . . . . . 164

7.3 Historical Perspective . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164

7.4 Petroleum Refinery and Biorefinery . . . . . . . . . . . . . . . . . . . . . . . . . . . 168

7.5 Refining of Upgraded Products . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174

7.6 Opportunities for Refining Pyrolysis Products . . . . . . . . . . . . . . . . . . . 178

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180

8 Future Developments. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183

8.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183

8.1.1 World Theoretical Limit of Biomass Supply . . . . . . . . . . . . . . 184

8.1.2 High-yield Energy Crops . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1858.1.3 Food Versus Fuel Delineation . . . . . . . . . . . . . . . . . . . . . . . . . . 186

8.1.4 Thermodynamic Efficiency (Exergy Analysis) . . . . . . . . . . . . 187

8.1.5 Biofuel Upgradation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187

8.1.6 Carbon Credits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188

8.2 Social and Political Issues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189

8.2.1 The Promise of Algae: Energy Security . . . . . . . . . . . . . . . . . . 190

8.3 Environmental Impacts of Biomass Production . . . . . . . . . . . . . . . . . . 191

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193

Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195

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