Table Of ContentGreen Energy and Technology
Maria Turco
Angelo Ausiello
Luca Micoli
Treatment of
Biogas for Feeding
High Temperature
Fuel Cells
Removal of Harmful Compounds by
Adsorption Processes
Green Energy and Technology
More information about this series at http://www.springer.com/series/8059
Maria Turco · Angelo Ausiello
Luca Micoli
Treatment of Biogas
for Feeding High
Temperature Fuel Cells
Removal of Harmful Compounds
by Adsorption Processes
1 3
Maria Turco Luca Micoli
Department of Chemical Engineering, Department of Chemical Engineering,
Materials and Industrial Production Materials and Industrial Production
University of Naples Federico II University of Naples Federico II
Naples Naples
Italy Italy
Angelo Ausiello
Department of Chemical Engineering,
Materials and Industrial Production
University of Naples Federico II
Naples
Italy
ISSN 1865-3529 ISSN 1865-3537 (electronic)
Green Energy and Technology
ISBN 978-3-319-03214-6 ISBN 978-3-319-03215-3 (eBook)
DOI 10.1007/978-3-319-03215-3
Library of Congress Control Number: 2016931600
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To Prof. Umberto Costantino
and Prof. Giulio Alberti
Preface
Professor Maria Turco is Associated Professor at the Faculty of Engineering
of University “Federico II” of Napoli, where she teaches courses in “Industrial
Chemistry,” “Traditional and Innovative Fuels and Fuel Cells,” and “Catalysis”.
Professor Maria Turco carried out research activity, mainly in the field of the tech-
nologies for the production of energy with low environmental impact, such as
catalytic processes for removal of gaseous pollutants and processes for hydrogen
production. A large part of her recent activity is devoted to the study of fuel cells
for mobile or stationary applications.
Dr. Luca Micoli is a Ph.D. Chemical Engineer and researcher at the Department
of Chemical, Materials and Production Engineering of University “Federico II” of
Naples. His research activities are focused on fuel cells for different applications,
such as portable and stationary power generation, and on methodologies for the
clean-up stage.
Dr. Angelo Ausiello is a Ph.D. student in Chemical Engineering at the
University of Naples “Federico II”. His research activities include the develop-
ment of energy production systems based on fuel cells fueled by biogas produced
from the anaerobic digestion of different kinds of biomass.
The interest in fuel cells (FCs) technology is growing continuously, since they
have high potential of applications for many reasons such as emission-free energy
supply, high efficiency, wide range of power generation from a few watts to some
megawatts, and the possibility to be fed with different fuels including biogas.
These and many other advantages have encouraged academic and industrial
researchers worldwide to improve performances and the cost-effectiveness of fuel
cells. Nowadays, the considerable level of technological readiness that has been
reached finally allows to expect that fuel cells will penetrate into a large market.
The authors of this book are of the opinion that the FC technology has great
potential and that it can play a key role in adapting the worldwide energy supply
systems toward efficiencies and emission levels allowing a long-term stable and
sustainable development for the world economy and environment.
vii
viii Preface
Nevertheless, the authors consider that efforts on improving performances FCs
are not enough to enter the market successfully, because the quality and the purity
of the fuels, in particular biogas, need specific attention due to the presence of
impurities or undesirable compounds in the fuels that can damage the components
of a fuel cell (electrodes and electrolyte) and reduce the overall efficiency.
In the field of stationary power production high temperature fuel cells (MCFC
and SOFC) are emerging as a promising alternative to combustion heat engines for
the production of electrical power and cogeneration, and the possibility of feed-
ing biogas as alternative fuel increases the interest for the evident environmental
advantages. The use of biogas as fuel for FCs is an important task in the devel-
opment of technologies for production of energy from renewable sources and is
largely treated in the literature. At the same time gas purification processes based
on adsorption on microporus materials are widely studied in the literature. This
book reviews in a comprehensive way the main aspects regarding the purification
procedures of biogas for fuelling MCFCs or SOFCs.
In Chap. 1 different processes of biogas production (fermentation, digestion,
etc.) are described evidencing the dependence of the gas composition and con-
tent of noxious compounds on the specific process and on the source of biomass.
Attention is focused on the different types of compounds that can be harmful for
high temperature fuel cells and their reformer systems such as sulfur compounds
inorganic and organic) and siloxanes.
Chapter 2 summarizes the operating principles of the fuel cells in order to pro-
vide an understanding of the basic operations.
Chapter 3 is an overview of the main challenges that such new technology
meets shifting from a well-established niche market to the civilian one in a com-
mercialization process.
In Chap. 4 the technologies proposed in the literature for removal of noxious
substances are reviewed with particular attention to adsorption processes. The
adsorbent materials that appear the most probable candidates for this applica-
tion (based on zeolites and activated carbons) are described with emphasis on the
methodologies aimed to improve the adsorption properties. The regeneration of
the materials is also taken into account.
In Chaps. 5–7 the effects of sulfur compounds and siloxanes on performances
of MCFC and SOFC are described. The mechanisms of interaction of these com-
pounds with the components of FCs (electrodes and electrolyte) are also treated.
Contents
1 Processes of Biogas Production: Anaerobic Digestion
and Thermal Gasification ..................................... 1
1.1 Introduction ............................................ 1
1.2 Anaerobic Digestion ...................................... 2
1.2.1 Anaerobic Digestion Steps .......................... 3
1.2.2 Substrates for Anaerobic Digestion ................... 7
1.3 Improvement of Biogas Production Techniques ................ 10
1.3.1 Pretreatment of Biomass ........................... 10
1.4 Co-digestion ............................................ 12
1.5 Reactors ............................................... 13
1.6 Thermal Gasification ..................................... 14
1.6.1 Operating Variables ............................... 15
1.6.2 Gasifying Agent .................................. 16
1.6.3 Updraft Gasification ............................... 16
1.6.4 Downdraft Gasification ............................ 20
References .................................................. 21
2 Fuel Cells Operating and Structural Features
of MCFCs and SOFCs ....................................... 31
2.1 Introduction ............................................ 31
2.1.1 Fuel Cells ....................................... 32
2.1.2 Comparison with Batteries .......................... 33
2.1.3 Comparison with Heat Engine ....................... 34
2.2 Sectors of Applications .................................... 35
2.3 History of Fuel Cells ..................................... 36
2.4 Fuel Cells Fundamentals .................................. 38
2.4.1 Fuel Cell Operations ............................... 41
2.5 Characteristics and Features ................................ 44
2.5.1 High Efficiency ................................... 44
2.5.2 Reduced Harmful Emissions ........................ 45
2.5.3 Modularity ...................................... 46
ix
x Contents
2.5.4 Prompt Load Following ............................ 46
2.5.5 Static Nature ..................................... 47
2.5.6 Range of Applications and Fuel Flexibility ............. 47
2.5.7 High Cost ....................................... 48
2.5.8 Low Durability ................................... 48
2.5.9 Hydrogen Infrastructure ............................ 48
2.5.10 Water Balance .................................... 49
2.5.11 Parasitic Load .................................... 50
2.5.12 Codes, Standards, Safety, and Public Awareness ......... 50
2.5.13 Types .......................................... 51
2.6 Fuel Cells Types ......................................... 52
2.6.1 Proton Exchange Membrane Fuel Cell (PEMFC) ........ 52
2.6.2 Alkaline Fuel Cell (AFC) ........................... 53
2.6.3 Phosphoric Acid Fuel Cells (PAFC) ................... 54
2.6.4 Direct Methanol Fuel Cells (DMFC) .................. 54
2.6.5 Molten Carbonate Fuel Cell (MCFC) ................. 55
2.6.6 Solid Oxide Fuel Cell (SOFC) ....................... 63
References .................................................. 68
3 Fuel Cells Challenges ........................................ 77
3.1 Introduction ............................................ 77
3.2 The Hydrogen Economy, Hydrogen Fuelling Infrastructure,
and Fuel Cell Technology .................................. 78
3.2.1 Chicken-Egg Issue ................................ 78
3.2.2 Independence of Fuel Cell Technology ................ 79
3.3 Major Barriers for Commercialization of Fuel Cells ............. 80
3.3.1 Costs of Fuel Cell Itself ............................ 81
3.3.2 Key Technical Barriers ............................. 81
3.3.3 Theoretical Solutions of Fuel Cell Scaling-Up Issues ..... 82
3.4 The Market for FC Products ................................ 84
3.5 Contextual Characteristics ................................. 85
3.5.1 Fuel Cell System Cost Reduction ..................... 87
3.6 Fuel Cell Combined Heat and Power Systems .................. 89
References .................................................. 90
4 The Use of Biogas in MCFCs and SOFCs Technology:
Adsorption Processes and Adsorbent Materials for Removal
of Noxious Compounds ....................................... 95
4.1 Introduction ............................................ 95
4.2 Substrates .............................................. 96
4.3 Biogas to Biomethane .................................... 98
4.3.1 Biogas Upgrading ................................. 99
